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Sample records for anti-west nile virus

  1. What's West Nile Virus?

    Science.gov (United States)

    ... Help White House Lunch Recipes What's West Nile Virus? KidsHealth > For Kids > What's West Nile Virus? Print A A A Text Size en español ¿Qué es el Virus del Nilo Occidental? What exactly is the West ...

  2. FAQ: General Questions about West Nile Virus

    Science.gov (United States)

    ... Public Service Videos General Questions About West Nile Virus Recommend on Facebook Tweet Share Compartir On this ... West Nile virus cases? What is West Nile virus? West Nile virus is an arthropod-borne virus ( ...

  3. West Nile Virus Cases, 2006-present

    Data.gov (United States)

    U.S. Department of Health & Human Services — This dataset contains positive cases of West Nile virus found in humans by county of residence, 2006-present. Humans usually become infected with West Nile virus by...

  4. Mental Status after West Nile Virus Infection

    OpenAIRE

    Haaland, Kathleen Y.; Sadek, Joseph; Pergam, Steven; Echevarria, Leonor A.; Davis, Larry E.; Goade, Diane; Harnar, Joanne; Nofchissey, Robert A.; Sewel, C. Mack; Ettestad, Paul

    2006-01-01

    Mental status after acute West Nile virus infection has not been examined objectively. We compared Telephone Interview for Cognitive Status scores of 116 patients with West Nile fever or West Nile neuroinvasive disease. Mental status was poorer and cognitive complaints more frequent with West Nile neuroinvasive disease (p = 0.005).

  5. West Nile virus: a growing concern?

    OpenAIRE

    Gould, L. Hannah; Fikrig, Erol

    2004-01-01

    West Nile virus was first detected in North America in 1999 and has subsequently spread throughout the United States and Canada and into Mexico and the Caribbean. This review describes the epidemiology and ecology of West Nile virus in North America and the prospects for effective treatments and vaccines.

  6. West Nile virus: North American experience

    Science.gov (United States)

    Hofmeister, Erik K.

    2011-01-01

    West Nile virus, a mosquito-vectored flavivirus of the Japanese encephalitis serogroup, was first detected in North America following an epizootic in the New York City area in 1999. In the intervening 11 years since the arrival of the virus in North America, it has crossed the contiguous USA, entered the Canadian provinces bordering the USA, and has been reported in the Caribbean islands, Mexico, Central America and, more recently, South America. West Nile virus has been reported in over 300 species of birds in the USA and has caused the deaths of thousands of birds, local population declines of some avian species, the clinical illness and deaths of thousands of domestic horses, and the clinical disease in over 30 000 Americans and the deaths of over 1000. Prior to the emergence of West Nile virus in North America, St. Louis encephalitis virus and Dengue virus were the only other known mosquito-transmitted flaviviruses in North America capable of causing human disease. This review will discuss the North American experience with mosquito-borne flavivirus prior to the arrival of West Nile virus, the entry and spread of West Nile virus in North America, effects on wild bird populations, genetic changes in the virus, and the current state of West Nile virus transmission.

  7. NNDSS - Table II. West Nile virus disease

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. West Nile virus disease - 2015.In this Table, provisional cases of selected notifiable diseases (≥1,000 cases reported during the preceding...

  8. West Nile Virus (WNV seroprevalence in a blood donors group of Milan

    Directory of Open Access Journals (Sweden)

    Giovanna Lunghi

    2012-09-01

    Full Text Available A seroprevalence study for anti West Nile virus was carried out among 864 healthy blood donors living in the metropolitan area of Milan by using a commercially available ELISA method. In addition, the performance of a novel ELISA assay for WNV antibodies was assessed. The sero-prevalence rate of WNV antibodies was 0.57% thus showing that WNV is likely circulating also in this up to now unknown area. The overall sensitivity and specificity of the novel ELISA were 99.9% and 45.4%, respectively, well comparable with that of the chosen reference immunoenzimatic method.

  9. West Nile Virus Drug Discovery

    Directory of Open Access Journals (Sweden)

    Siew Pheng Lim

    2013-12-01

    Full Text Available The outbreak of West Nile virus (WNV in 1999 in the USA, and its continued spread throughout the Americas, parts of Europe, the Middle East and Africa, underscored the need for WNV antiviral development. Here, we review the current status of WNV drug discovery. A number of approaches have been used to search for inhibitors of WNV, including viral infection-based screening, enzyme-based screening, structure-based virtual screening, structure-based rationale design, and antibody-based therapy. These efforts have yielded inhibitors of viral or cellular factors that are critical for viral replication. For small molecule inhibitors, no promising preclinical candidate has been developed; most of the inhibitors could not even be advanced to the stage of hit-to-lead optimization due to their poor drug-like properties. However, several inhibitors developed for related members of the family Flaviviridae, such as dengue virus and hepatitis C virus, exhibited cross-inhibition of WNV, suggesting the possibility to re-purpose these antivirals for WNV treatment. Most promisingly, therapeutic antibodies have shown excellent efficacy in mouse model; one of such antibodies has been advanced into clinical trial. The knowledge accumulated during the past fifteen years has provided better rationale for the ongoing WNV and other flavivirus antiviral development.

  10. Why We Need West Nile Virus Testing

    Centers for Disease Control (CDC) Podcasts

    2016-09-27

    Dr. Rodrigo Hasbun, a professor of infectious diseases at McGovern Medical School at UT Health, discusses the need for West Nile virus testing in Texas.  Created: 9/27/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 9/27/2016.

  11. NNDSS - Table II. West Nile virus disease

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. West Nile virus disease - 2016. In this Table, provisional* cases of selected†notifiable diseases (≥1,000 cases reported during the preceding...

  12. Skin manifestations of West Nile virus infection.

    Science.gov (United States)

    Del Giudice, P; Schuffenecker, I; Zeller, H; Grelier, M; Vandenbos, F; Dellamonica, P; Counillon, E

    2005-01-01

    West Nile virus (WNV) infection is a potentially lethal arbovirus infection. Many notable outbreaks have occurred during the last few years throughout the world, including Europe and the USA. The severity of the disease is mainly related to the neurological complications. A maculopapular exanthema is reported as a clinical sign of the disease. Recently an outbreak of WNV infection occurred in southern France. Three patients out of 6 had a similar skin roseola-like eruption. The cluster of 3 cases of similar febrile roseola of unexplained cause during the same week led to the diagnosis of the first WNV human outbreak in France for 40 years. PMID:16286745

  13. [West Nile virus: a reality in Mexico].

    Science.gov (United States)

    Téllez, Ildefonso; Calderón, Oscar; Franco-Paredes, Carlos; del Río, Carlos

    2006-01-01

    West Nile virus (WNV) is a RNA virus of the Flaviridae, genus flavivirus family. It is a neuropathogenic virus causing disease in birds, horses and humans. WNVis transmitted by the vector mosquito Culex sp. The virus life 's cycle includes mosquitoes as vectors and birds as natural hosts. Humans are accidental hosts. Since the introduction of the Epidemiological Surveillance Program at the Ministry ofHealth. we have documented 90 positive test results among birds out of 1,223 cases studied in Mexico as of September IS. 2005. The incubation period in humans after a mosquito bite ranges from 3 to 14 days. Disease is characterized by early onset fever, general malaise, decreased appetite, nausea, vomiting, headaches, myalgias, enlarged lymph nodes andrash. Neurological manifestations include encephalitis andflaccid paralysis, which are present in less than 1% of subjects infected with WNV. Older patients display more adverse outcomes including death. The diagnosis is made by the determination of specific IgM and JgG antibodies in serum and/or cerebrospinal fluid. There is no antiviral treatment to date against WNV but interferon ?2b, and WNVspec4ic-immunoglobulin have been used Prevention is therefore the key to control the infection.

  14. NNDSS - Table II. Varicella to West Nile virus disease

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Varicella to West Nile virus disease - 2014. In this Table, all conditions with a 5-year average annual national total of more than or equals...

  15. Recent progress in West Nile virus diagnosis and vaccination

    Directory of Open Access Journals (Sweden)

    De Filette Marina

    2012-03-01

    Full Text Available Abstract West Nile virus (WNV is a positive-stranded RNA virus belonging to the Flaviviridae family, a large family with 3 main genera (flavivirus, hepacivirus and pestivirus. Among these viruses, there are several globally relevant human pathogens including the mosquito-borne dengue virus (DENV, yellow fever virus (YFV, Japanese encephalitis virus (JEV and West Nile virus (WNV, as well as tick-borne viruses such as tick-borne encephalitis virus (TBEV. Since the mid-1990s, outbreaks of WN fever and encephalitis have occurred throughout the world and WNV is now endemic in Africa, Asia, Australia, the Middle East, Europe and the Unites States. This review describes the molecular virology, epidemiology, pathogenesis, and highlights recent progress regarding diagnosis and vaccination against WNV infections.

  16. Up-to-date knowledge of West Nile virus infection

    Directory of Open Access Journals (Sweden)

    Hrnjaković-Cvjetković Ivana

    2009-01-01

    Full Text Available Virus West Nile virus is a single-stranded RNA virus of the family Flaviviridae, genus Flavivirus. Epidemiology West Nile virus is maintained in the cycle involving culicine mosquitoes and birds .Humans typically acquire West Nile infection through a bite from infected adult mosquito. Person to person transmission can occur through organ transplantation, blood and blood product transfusions, transplacentally and via brest milk. Human cases of West Nile infections were recorded in Africa, Israel, Russia, India, Pakistan. In Romania in 1996 West Nile fever occurred with hundreds of neurologic cases and 17 fatalities. First human cases in the United States were in New York City where 59 persons were infected and had fever, meningitis, encephalitis and flaccid paralysis. Clinical manifestation Most human cases are asymptomatic. The majority of symptomatic patients have a self limited febrile illness. Fatigue, nausea, vomiting, eye pain, headache, myalgias, artralgias, lymphadenopathy and rash are common complaints. Less than 1% of all infected persons develop more severe neurologic illness including meningitis, encefalitis and flaccid paralysis. Laboratory diagnosis Diagnosis of West Nile virus infection is based on serologic testing, isolation of virus from patient samples and detection of viral antigen or viral genom. ELISA test and indirect immunofluorescenceassay are used for detecting IgM and IgG antibodies in serum and cerebrospinal fluid. Treatment In vitro studies have suggested that ribavirin and interferon alfa -2b may be useful in the treatment of West Nile virus disease. Prevention The most important measures are mosquito control program and personal protective measures. .

  17. The Buzz-z-z on West Nile Virus

    Centers for Disease Control (CDC) Podcasts

    2012-01-12

    In this podcast for kids, the Kidtastics talk about West Nile Virus and how to protect yourself from it.  Created: 1/12/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 1/12/2012.

  18. Purpura fulminans associated with acute West Nile virus encephalitis.

    Science.gov (United States)

    Shah, Sheevam; Fite, Laura Paul; Lane, Natalie; Parekh, Palak

    2016-02-01

    Purpura fulminans is a progressive thrombotic disorder that presents with widespread purpura due to deficiency or dysfunction of protein C or protein S. Lesions present as well-demarcated erythematous macules that progress to irregular areas of hemorrhagic necrosis.West Nile virus is a member of the Flaviviridae family transmitted to humans through the bite of various mosquito species. It manifests as West Nile fever in 25% of those infected and less commonly as neuroinvasive disease. An African American man in his fortiespresented with altered mental status and was noted to have evidence of disseminated intravascular coagulation according to his lab data. He then developed dusky skin discoloration and systemic flaccid bullae with desquamation. Biopsy was consistent with purpura fulminans and the patient eventually developed symmetric peripheral gangrene, requiring amputations of all four extremities. Infectious work up revealed positive testing for IgM and IgG antibodies in serum and cerebrospinal fluid leading to the diagnosis of acute West Nile Virus encephalitis. We present this case to describe the rarely reported association of purpura fulminans with West Nile Virus infection.

  19. Chronic West Nile virus infection in kea (Nestor notabilis).

    Science.gov (United States)

    Bakonyi, Tamás; Gajdon, Gyula K; Schwing, Raoul; Vogl, Wolfgang; Häbich, Annett-Carolin; Thaller, Denise; Weissenböck, Herbert; Rudolf, Ivo; Hubálek, Zdenek; Nowotny, Norbert

    2016-02-01

    Six kea (Nestor notabilis) in human care, naturally infected with West Nile virus (WNV) lineage 2 in Vienna, Austria, in 2008, developed mild to fatal neurological signs. WNV RNA persisted and the virus evolved in the birds' brains, as demonstrated by (phylo)genetic analyses of the complete viral genomes detected in kea euthanized between 2009 and 2014. WNV antibodies persisted in the birds, too. Chronic WNV infection in the brain might contribute to the circulation of the virus through oral transmission to predatory birds.

  20. Risk assessment on severe hazards to China caused by West Nile virus

    Institute of Scientific and Technical Information of China (English)

    CHEN Jiming; SUN Yingxue; WANG Zhiliang; SHEN Chaojian; XIE Zhonglun; WANG Ximing

    2004-01-01

    Recent West Nile virus epidemics in USA draw worldwide concerns. Here the basic biological and epidemiologicai features of the virus are analyzed along with the special immunity of humans and animals, the immigration of birds and the natural environments in China. The risk of severe hazards to China caused by West Nile virus is assessed not high thereafter.

  1. Potential for New York mosquitoes to transmit West Nile virus.

    Science.gov (United States)

    Turell, M J; O'Guinn, M; Oliver, J

    2000-03-01

    We evaluated the potential for several North American mosquito species to transmit the newly introduced West Nile (WN) virus. Mosquitoes collected in the New York City Metropolitan Area during the recent (1999) WN outbreak were allowed to feed on chickens infected with WN virus isolated from a crow that had died during this outbreak. These mosquitoes were tested approximately 2 weeks later to determine infection, dissemination, and transmission rates. Culex pipiens mosquitoes were highly susceptible to infection, and nearly all individuals with a disseminated infection did transmit WN virus by bite. In contrast, Aedes vexans were only moderately susceptible to oral infection; however, those individuals inoculated with WN virus did transmit virus by bite.

  2. Localization of West Nile Virus in monkey brain: double staining antigens immunohistochemically of neurons, neuroglia cells and West Nile Virus

    OpenAIRE

    He, Xianli; Ren, Junping; Xu, Fangling; Ferguson, Monique R; Li, Guangyu

    2009-01-01

    West Nile virus (WNV) can cause encephalitis or meningitis that affects brain tissue, which can also lead to permanent neurological damage that can be fatal. To our knowledge, no consistent double immunohistochemical staining of neurons, neuroglia cells, and WNV has yet been reported. To establish a method for performing double-label immunohistochemical detection of neurons, neuroglia cells and WNV, examining the pathological characteristics of WNV-infected neurons, neuroglia cells, and inves...

  3. Noncoding subgenomic flavivirus RNA: multiple functions in West Nile virus pathogenesis and modulation of host responses

    NARCIS (Netherlands)

    Roby, J.A.; Pijlman, G.P.; Wilusz, J.; Khromykh, A.A.

    2014-01-01

    Flaviviruses are a large group of positive strand RNA viruses transmitted by arthropods that include many human pathogens such as West Nile virus (WNV), Japanese encephalitis virus (JEV), yellow fever virus, dengue virus, and tick-borne encephalitis virus. All members in this genus tested so far are

  4. West Nile virus in livestock and wildlife

    Science.gov (United States)

    McLean, R.G.; Ubico, S.R.; Bourne, D.; Komar, N.

    2002-01-01

    WN virus is one of the most ubiquitous arboviruses occurring over a broad geographical range and in a wide diversity of vertebrate host and vector species. The virus appears to be maintained in endemic foci on the African continent and is transported annually to temperate climates to the north in Europe and to the south in South Africa. Reports of clinical disease due to natural WN virus infection in wild or domestic animals were much less common than reports of infection (virus isolation or antibody detection). Until recently, records of morbidity and mortality in wild birds were confined to a small number of cases and infections causing encephalitis, sometimes fatal, in horses were reported infrequently. In the period 1996-2001, there was an increase in outbreaks of illness due to WN virus in animals as well as humans. Within the traditional range of WN virus, encephalitis was reported in horses in Italy in 1998 and in France in 2000. The first report of disease and deaths caused by WN virus infection in domestic birds was reported in Israel in 1997-1999, involving hundreds of young geese. In 1999 WN virus reached North America and caused an outbreak of encephalitis in humans in the New York area at the same time as a number of cases of equine encephalitis and deaths in American crows and a variety of other bird species, both North American natives and exotics. Multi-state surveillance for WN virus has been in place since April 2000 and has resulted in the detection of WN virus in thousands of dead birds from an increasing number of species in North America, and also in several species of mammals. The surveillance system that has developed in North America because of the utility of testing dead birds for the rapid detection of WN virus presence has been a unique integration of public health and wildlife health agencies. It has been suggested that the recent upsurge in clinical WN virus infection in wild and domestic animals as well as in humans may be related to

  5. West Nile virus in livestock and wildlife.

    Science.gov (United States)

    McLean, R G; Ubico, S R; Bourne, D; Komar, N

    2002-01-01

    WN virus is one of the most ubiquitous arboviruses occurring over a broad geographical range and in a wide diversity of vertebrate host and vector species. The virus appears to be maintained in endemic foci on the African continent and is transported annually to temperate climates to the north in Europe and to the south in South Africa. Reports of clinical disease due to natural WN virus infection in wild or domestic animals were much less common than reports of infection (virus isolation or antibody detection). Until recently, records of morbidity and mortality in wild birds were confined to a small number of cases and infections causing encephalitis, sometimes fatal, in horses were reported infrequently. In the period 1996-2001, there was an increase in outbreaks of illness due to WN virus in animals as well as humans. Within the traditional range of WN virus, encephalitis was reported in horses in Italy in 1998 and in France in 2000. The first report of disease and deaths caused by WN virus infection in domestic birds was reported in Israel in 1997-1999, involving hundreds of young geese. In 1999 WN virus reached North America and caused an outbreak of encephalitis in humans in the New York area at the same time as a number of cases of equine encephalitis and deaths in American crows and a variety of other bird species, both North American natives and exotics. Multi-state surveillance for WN virus has been in place since April 2000 and has resulted in the detection of WN virus in thousands of dead birds from an increasing number of species in North America, and also in several species of mammals. The surveillance system that has developed in North America because of the utility of testing dead birds for the rapid detection of WN virus presence has been a unique integration of public health and wildlife health agencies. It has been suggested that the recent upsurge in clinical WN virus infection in wild and domestic animals as well as in humans may be related to

  6. Clinical Manifestations and Outcomes of West Nile Virus Infection

    Directory of Open Access Journals (Sweden)

    James J. Sejvar

    2014-02-01

    Full Text Available Since the emergence of West Nile virus (WNV in North America in 1999, understanding of the clinical features, spectrum of illness and eventual functional outcomes of human illness has increased tremendously. Most human infections with WNV remain clinically silent. Among those persons developing symptomatic illness, most develop a self-limited febrile illness. More severe illness with WNV (West Nile neuroinvasive disease, WNND is manifested as meningitis, encephalitis or an acute anterior (polio myelitis. These manifestations are generally more prevalent in older persons or those with immunosuppression. In the future, a more thorough understanding of the long-term physical, cognitive and functional outcomes of persons recovering from WNV illness will be important in understanding the overall illness burden.

  7. West Nile Virus: What You Need to Know Now - August 2012

    Centers for Disease Control (CDC) Podcasts

    2012-08-21

    This podcast lists the states where most of the 2012 West Nile viruses have been reported and explains how people can protect themselves from West Nile virus.  Created: 8/21/2012 by .   Date Released: 8/21/2012.

  8. Clinical West Nile virus infection in 2 horses in western Canada.

    Science.gov (United States)

    Abutarbush, Sameeh M; O'Connor, Brendan P; Clark, Chris; Sampieri, Francesca; Naylor, Jonathan M

    2004-04-01

    Two horses had a history of ataxia and weakness or recumbency. One recovered and was diagnosed with West Nile virus (WNV) infection by serologic testing. The other was euthanized; it had meningoencephalomyelitis, WNV was detected by polymerase chain reaction. West Nile virus infection is an emerging disease. Year 2002 is the first year in which cases have been seen in Saskatchewan.

  9. Overview of West Nile Virus Transmission and Epidemiology.

    Science.gov (United States)

    Troupin, Andrea; Colpitts, Tonya M

    2016-01-01

    West Nile virus (WNV) is a mosquito-borne flavivirus that can cause mild-to-severe disease in humans and horses. WNV was first documented in Uganda in 1937 and passed through the majority of Africa, West Asia, and Europe before arriving in the USA (with infections in New York City in 1999). After the spread of the virus on the US east coast, it traveled westward, northward, and southward through the USA and into Central and South America. WNV can cause fever, rashes, nausea, vomiting, and potentially neuroinvasive disease or death. The virus is sustained through a mosquito-bird-mosquito cycle and there are many species that are competent vectors. Unfortunately, there are no vaccines and the only treatment is supportive care. This chapter highlights the epidemiology and transmission of WNV and provides insight into some of the challenges of controlling WNV disease.

  10. Experimental Infection of Cats and Dogs with West Nile Virus

    OpenAIRE

    Austgen, Laura E.; Bowen, Richard A.; Bunning, Michel L.; Davis, Brent S.; Mitchell, Carl J.; Chang, Gwong-Jen J.

    2004-01-01

    Domestic dogs and cats were infected by mosquito bite and evaluated as hosts for West Nile virus (WNV). Viremia of low magnitude and short duration developed in four dogs but they did not display signs of disease. Four cats became viremic, with peak titers ranging from 103.0 to 104.0 PFU/mL. Three of the cats showed mild, non-neurologic signs of disease. WNV was not isolated from saliva of either dogs or cats during the period of viremia. An additional group of four cats were exposed to WNV o...

  11. Genetically delivered antibody protects against West Nile virus

    OpenAIRE

    Pereboev, Alexander; Borisevich, Viktoriya; Tsuladze, George; Shakhmatov, Mikhail; Hudman, Deborah; Kazachinskaia, Elena; Razumov, Ivan; Svyatchenko, Viktor; Loktev, Valery; Yamshchikov, Vladimir

    2007-01-01

    Gene-based delivery of recombinant antibody genes is a promising therapeutic strategy offering numerous advantages including sustained antibody levels, better safety profile and lower production cost. Here we describe generation of a recombinant antibody Fc-9E2 comprising a fusion protein between human Fc of IgG1 and a single-chain Fv derived from a hybridoma 9E2 secreting a mAb neutralizing West Nile virus (WNV). Fc-9E2 was shown to retain parental mAb's specificity and WNV-neutralizing capa...

  12. Potential North American vectors of West Nile virus.

    Science.gov (United States)

    Turell, M J; Sardelis, M R; Dohm, D J; O'Guinn, M L

    2001-12-01

    The outbreak of disease in the New York area in 1999 due to West Nile (WN) virus was the first evidence of the occurrence of this virus in the Americas. To determine potential vectors, more than 15 mosquito species (including Culex pipiens, Cx. nigripalpus, Cx. quinquefasciatus, Cx. salinarius, Aedes albopictus, Ae. vexans, Ochlerotatus japonicus, Oc. sollicitans, Oc. taeniorhynchus, and Oc. triseriatus) from the eastern United States were evaluated for their ability to serve as vectors for the virus isolated from birds collected during the 1999 outbreak in New York. Mosquitoes were allowed to feed on one- to four-day old chickens that had been inoculated with WN virus 1-3 days previously. The mosquitoes were incubated for 12-15 days at 26 degrees C and then allowed to refeed on susceptible chickens and assayed to determine transmission and infection rates. Several container-breeding species (e.g., Ae. albopictus, Oc. atropalpus, and Oc. japonicus) were highly efficient laboratory vectors of WN virus. The Culex species were intermediate in their susceptibility. However, if a disseminated infection developed, all species were able to transmit WN virus by bite. Factors such as population density, feeding preference, longevity, and season of activity also need to be considered in determining the role these species could play in the transmission of WN virus.

  13. European Surveillance for West Nile Virus in Mosquito Populations

    Directory of Open Access Journals (Sweden)

    Nicholas Johnson

    2013-10-01

    Full Text Available A wide range of arthropod-borne viruses threaten both human and animal health either through their presence in Europe or through risk of introduction. Prominent among these is West Nile virus (WNV, primarily an avian virus, which has caused multiple outbreaks associated with human and equine mortality. Endemic outbreaks of West Nile fever have been reported in Italy, Greece, France, Romania, Hungary, Russia and Spain, with further spread expected. Most outbreaks in Western Europe have been due to infection with WNV Lineage 1. In Eastern Europe WNV Lineage 2 has been responsible for human and bird mortality, particularly in Greece, which has experienced extensive outbreaks over three consecutive years. Italy has experienced co-circulation with both virus lineages. The ability to manage this threat in a cost-effective way is dependent on early detection. Targeted surveillance for pathogens within mosquito populations offers the ability to detect viruses prior to their emergence in livestock, equine species or human populations. In addition, it can establish a baseline of mosquito-borne virus activity and allow monitoring of change to this over time. Early detection offers the opportunity to raise disease awareness, initiate vector control and preventative vaccination, now available for horses, and encourage personal protection against mosquito bites. This would have major benefits through financial savings and reduction in equid morbidity/mortality. However, effective surveillance that predicts virus outbreaks is challenged by a range of factors including limited resources, variation in mosquito capture rates (too few or too many, difficulties in mosquito identification, often reliant on specialist entomologists, and the sensitive, rapid detection of viruses in mosquito pools. Surveillance for WNV and other arboviruses within mosquito populations varies between European countries in the extent and focus of the surveillance. This study reviews the

  14. West Nile virus and USUTU--a threat to Poland.

    Science.gov (United States)

    Moniuszko-Malinowska, Anna; Czupryna, Piotr; Dunaj, Justyna; Zajkowska, Joanna; Siemieniako, Agnieszka; Pancewicz, Sławomir

    2016-01-01

    In recent years emergence of new infectious diseases and the growing spread of pathogens to new areas is observed. Most of these pathogens are zoonotic viruses and their transmission route is from animals to humans and vice versa. These so called emerging and re-emerging pathogens that were present previously only in Africa and Asia are becoming a threat to European countries. These include, e.g. West Nile virus and USUTU virus. The aim of the study is to present the clinical course of infections caused by WVN and USUTU, diagnostic and therapeutic possibilities and, above all, the current epidemiological situation of these infections in the world. We also tried to answer the question whether, there is a risk of infection with these viruses in Poland. After analyzing the available literature we venture a conclusion that in Poland there is a risk of WNV and USUTU infection. Global warming, change of socio-economic conditions, travelling greatly affect the spread of these viruses. In addition there are confirmed human cases of these diseases in countries neighboring Poland, as well as presence of both viruses and the presence of vectors (Culex pipiens sl and Culex torrentium (Diptera: Culicidae)) in our country. All these facts indicate that there is a necessity of epidemiological studies and consideration of these pathogens in the differential diagnosis of febrile illness and neuroinfection. PMID:27344466

  15. Reported Neuroinvasive Cases of West Nile Virus by State, 2002-2014

    Data.gov (United States)

    U.S. Environmental Protection Agency — This map shows the average annual incidence of neuroinvasive West Nile virus disease in each state, which is calculated as the average number of new cases per...

  16. Reported Neuroinvasive Cases of West Nile Virus by State, 2002–2014

    Data.gov (United States)

    U.S. Environmental Protection Agency — This map shows the average annual incidence of neuroinvasive West Nile virus disease in each state, which is calculated as the average number of new cases per...

  17. The Role of Innate Immunity in Conditioning Mosquito Susceptibility to West Nile Virus

    Directory of Open Access Journals (Sweden)

    Abhishek N. Prasad

    2013-12-01

    Full Text Available Arthropod-borne viruses (arboviruses represent an emerging threat to human and livestock health globally. In particular, those transmitted by mosquitoes present the greatest challenges to disease control efforts. An understanding of the molecular basis for mosquito innate immunity to arbovirus infection is therefore critical to investigations regarding arbovirus evolution, virus-vector ecology, and mosquito vector competence. In this review, we discuss the current state of understanding regarding mosquito innate immunity to West Nile virus. We draw from the literature with respect to other virus-vector pairings to attempt to draw inferences to gaps in our knowledge about West Nile virus and relevant vectors.

  18. Use of Testing for West Nile Virus and Other Arboviruses.

    Science.gov (United States)

    Vanichanan, Jakapat; Salazar, Lucrecia; Wootton, Susan H; Aguilera, Elizabeth; Garcia, Melissa N; Murray, Kristy O; Hasbun, Rodrigo

    2016-09-01

    In the United States, the most commonly diagnosed arboviral disease is West Nile virus (WNV) infection. Diagnosis is made by detecting WNV IgG or viral genomic sequences in serum or cerebrospinal fluid. To determine frequency of this testing in WNV-endemic areas, we examined the proportion of tests ordered for patients with meningitis and encephalitis at 9 hospitals in Houston, Texas, USA. We identified 751 patients (567 adults, 184 children), among whom 390 (52%) experienced illness onset during WNV season (June-October). WNV testing was ordered for 281 (37%) of the 751; results indicated acute infection for 32 (11%). Characteristics associated with WNV testing were acute focal neurologic deficits; older age; magnetic resonance imaging; empirically prescribed antiviral therapy; worse clinical outcomes: and concomitant testing for mycobacterial, fungal, or other viral infections. Testing for WNV is underutilized, and testing of patients with more severe disease raises the possibility of diagnostic bias in epidemiologic studies. PMID:27537988

  19. Use of Testing for West Nile Virus and Other Arboviruses

    Science.gov (United States)

    Vanichanan, Jakapat; Salazar, Lucrecia; Wootton, Susan H.; Aguilera, Elizabeth; Garcia, Melissa N.; Murray, Kristy O.

    2016-01-01

    In the United States, the most commonly diagnosed arboviral disease is West Nile virus (WNV) infection. Diagnosis is made by detecting WNV IgG or viral genomic sequences in serum or cerebrospinal fluid. To determine frequency of this testing in WNV-endemic areas, we examined the proportion of tests ordered for patients with meningitis and encephalitis at 9 hospitals in Houston, Texas, USA. We identified 751 patients (567 adults, 184 children), among whom 390 (52%) experienced illness onset during WNV season (June–October). WNV testing was ordered for 281 (37%) of the 751; results indicated acute infection for 32 (11%). Characteristics associated with WNV testing were acute focal neurologic deficits; older age; magnetic resonance imaging; empirically prescribed antiviral therapy; worse clinical outcomes: and concomitant testing for mycobacterial, fungal, or other viral infections. Testing for WNV is underutilized, and testing of patients with more severe disease raises the possibility of diagnostic bias in epidemiologic studies. PMID:27537988

  20. Avian hosts of West Nile virus in Arizona.

    Science.gov (United States)

    Komar, Nicholas; Panella, Nicholas A; Young, Ginger R; Brault, Aaron C; Levy, Craig E

    2013-09-01

    West Nile virus (WNV) causes sporadic outbreaks of human encephalitis in Phoenix, Arizona. To identify amplifying hosts of WNV in the Phoenix area, we blood-sampled resident birds and measured antibody prevalence following an outbreak in the East Valley of metropolitan Phoenix during summer, 2010. House sparrow (Passer domesticus), house finch (Haemorhous mexicanus), great-tailed grackle (Quiscalus mexicanus), and mourning dove (Zenaida macroura) accounted for most WNV infections among locally resident birds. These species roost communally after early summer breeding. In September 2010, Culex vector-avian host contact was 3-fold greater at communal bird roosts compared with control sites, as determined by densities of resting mosquitoes with previous vertebrate contact (i.e., blood-engorged or gravid mosquitoes). Because of the low competence of mourning doves, these were considered weak amplifiers but potentially effective free-ranging sentinels. Highly competent sparrows, finches, and grackles were predicted to be key amplifying hosts for WNV in suburban Phoenix. PMID:23857022

  1. Experimental Infections of Wild Birds with West Nile Virus

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    Elisa Pérez-Ramírez

    2014-02-01

    Full Text Available Avian models of West Nile virus (WNV disease have become pivotal in the study of infection pathogenesis and transmission, despite the intrinsic constraints that represents this type of experimental research that needs to be conducted in biosecurity level 3 (BSL3 facilities. This review summarizes the main achievements of WNV experimental research carried out in wild birds, highlighting advantages and limitations of this model. Viral and host factors that determine the infection outcome are analyzed in detail, as well as recent discoveries about avian immunity, viral transmission, and persistence achieved through experimental research. Studies of laboratory infections in the natural host will help to understand variations in susceptibility and reservoir competence among bird species, as well as in the epidemiological patterns found in different affected areas.

  2. Frequency of West Nile Virus Infection in Iranian Blood Donors.

    Science.gov (United States)

    Aghaie, Afsaneh; Aaskov, John; Chinikar, Sadegh; Niedrig, Matthias; Banazadeh, Soudabeh; Mohammadpour, Hashem Khorsand

    2016-09-01

    West Nile virus (WNV) can be transmitted by blood transfusions and organ transplants. This study was a retrospective study which was performed in Blood Transfusion Center to evaluate the WNV infection in blood donors in Iran. A total of 540 blood samples were taken from volunteer healthy donors who referred for blood donation to Chabahar Blood Center. The presence of WNV was studied by detecting immunoglobulin G (IgG) WNV by enzyme linked immune sorbent assay (ELISA). Demonstration of elevated WNV IgG confirmed by immunoflouorescence assay (IFA) Euroimmun kit. Out of the 540 samples 17.96 % (97 cases) were seropositive by ELISA and 1.48 % (8 cases) was seropositive by IFA. This means that 8.24 % of ELISA seropositive samples were confirmed by IFA. Special attention should be paid to criteria of donor selection, albeit positive results may be due to a previous infection in these donors. PMID:27429528

  3. Diversification of West Nile virus in a subtropical region

    Directory of Open Access Journals (Sweden)

    Mores Christopher N

    2009-07-01

    Full Text Available Abstract Background West Nile virus (WNV has spread across North, Central, and South America since its introduction in 1999. At the start of this spread, Florida was considered a potentially important area with regards to transmission due to its geographic, climatological, and demographic conditions. Curiously, the anticipated high levels of transmission or disease outbreaks have not been observed. As other studies have predicted that the lack of intense WNV transmission is not due to vector incompetence, we sought to evaluate the role of viral strain diversity in WNV transmission in Florida. Therefore, a phylogentic analysis was carried out on several isolates collected from three distinct locations in Florida. Results Contrasting with a positive control collected in Indian River County, Florida during 2003 that contains the original NY99 genotype with valanine at amino acid 159 of the envelope region, all of the isolates collected in 2005 contain the WN02 genotype composed of a substation with alanine at that position indicating the window of introduction of the WN02 genotype occurred between 2003 and 2005. From the eight isolates collected in Duval, Indian River, and Manatee Counties; there is also a silent nucleotide substitution that differentiates the isolates collected on the Atlantic side of the state compared to the isolate collected on the Gulf side, which groups closer to isolates from other locations near the Gulf. Conclusion As a whole, the Florida isolates contained numerous variable nucleotide and amino acid sites from the reference sequences, as well as each other; indicating greater nucleotide diversity within the Florida 2005 isolates than within other regions. Finally, a series of three amino acid substitutions surrounding a set of histidines located in the envelope coding region that hypothesized to play a role in conformational changes was found in the isolate collected in Indian River County, perhaps changing the

  4. Host sphingomyelin increases West Nile virus infection in vivo.

    Science.gov (United States)

    Martín-Acebes, Miguel A; Gabandé-Rodríguez, Enrique; García-Cabrero, Ana M; Sánchez, Marina P; Ledesma, María Dolores; Sobrino, Francisco; Saiz, Juan-Carlos

    2016-03-01

    Flaviviruses, such as the dengue virus and the West Nile virus (WNV), are arthropod-borne viruses that represent a global health problem. The flavivirus lifecycle is intimately connected to cellular lipids. Among the lipids co-opted by flaviviruses, we have focused on SM, an important component of cellular membranes particularly enriched in the nervous system. After infection with the neurotropic WNV, mice deficient in acid sphingomyelinase (ASM), which accumulate high levels of SM in their tissues, displayed exacerbated infection. In addition, WNV multiplication was enhanced in cells from human patients with Niemann-Pick type A, a disease caused by a deficiency of ASM activity resulting in SM accumulation. Furthermore, the addition of SM to cultured cells also increased WNV infection, whereas treatment with pharmacological inhibitors of SM synthesis reduced WNV infection. Confocal microscopy analyses confirmed the association of SM with viral replication sites within infected cells. Our results unveil that SM metabolism regulates flavivirus infection in vivo and propose SM as a suitable target for antiviral design against WNV. PMID:26764042

  5. Functional Analysis of West Nile Virus Proteins in Human Cells.

    Science.gov (United States)

    Kaufusi, Pakieli H; Tseng, Alanna; Nerurkar, Vivek R

    2016-01-01

    West Nile Virus (WNV) lineage 2 strains have been responsible for large outbreaks of neuroinvasive disease in the United States and Europe between 1999 and 2012. Different strains in this lineage have previously been shown to produce either severe or mild neuroinvasive disease in mice. Phylogenetic and amino acid comparisons between highly or less virulent lineage 2 strains have demonstrated that the nonstructural (NS) gene(s) were most variable. However, the roles of some of the NS proteins in virus life cycle are unknown. The aim of this chapter is to describe simple computational and experimental approaches that can be used to: (1) explore the possible roles of the NS proteins in virus life cycle and (2) test whether the subtle amino acid changes in WNV NS gene products contributed to the evolution of more virulent strains. The computational approaches include methods based on: (1) sequence similarity, (2) sequence motifs, and (3) protein membrane topology predictions. Highlighted experimental procedures include: (1) isolation of viral RNA from WNV-infected cells, (2) cDNA synthesis and PCR amplification of WNV genes, (3) cloning into GFP expression vector, (4) bacterial transformation, (5) plasmid isolation and purification, (6) transfection using activated dendrimers (Polyfect), and (7) immunofluorescence staining of transfected mammalian cells. PMID:27188549

  6. West Nile Virus in Resident Birds from Yucatan, Mexico.

    Science.gov (United States)

    Chaves, Andrea; Sotomayor-Bonilla, Jesus; Monge, Otto; Ramírez, Abigaíl; Galindo, Francisco; Sarmiento-Silva, Rosa Elena; Gutiérrez-Espeleta, Gustavo A; Suzán, Gerardo

    2016-01-01

    West Nile virus (WNV) in the Americas is thought to be transported at large spatial scales by migratory birds and locally spread and amplified by resident birds. Local processes, including interspecific interactions and dominance of passerine species recognized as competent reservoirs, may boost infection and maintain endemic cycles. Change in species composition has been recognized as an important driver for infection dynamics. Due to migration and changes in species diversity and composition in wintering grounds, changes in infection prevalence are expected. To these changes, we used PCR to estimate the prevalence of WNV in wild resident birds during the dry and rainy seasons of 2012 in Yucatan, Mexico. Serum samples were obtained from 104 wild birds, belonging to six orders and 35 species. We detected WNV in 14 resident birds, representing 11 species and three orders. Prevalences by order was Passeriformes (27%), Columbiformes (6%), and Piciformes (33%). Resident birds positive to WNV from Yucatan may be indicative of local virus circulation and evidence of past virus transmission activity. PMID:26540336

  7. Host sphingomyelin increases West Nile virus infection in vivo.

    Science.gov (United States)

    Martín-Acebes, Miguel A; Gabandé-Rodríguez, Enrique; García-Cabrero, Ana M; Sánchez, Marina P; Ledesma, María Dolores; Sobrino, Francisco; Saiz, Juan-Carlos

    2016-03-01

    Flaviviruses, such as the dengue virus and the West Nile virus (WNV), are arthropod-borne viruses that represent a global health problem. The flavivirus lifecycle is intimately connected to cellular lipids. Among the lipids co-opted by flaviviruses, we have focused on SM, an important component of cellular membranes particularly enriched in the nervous system. After infection with the neurotropic WNV, mice deficient in acid sphingomyelinase (ASM), which accumulate high levels of SM in their tissues, displayed exacerbated infection. In addition, WNV multiplication was enhanced in cells from human patients with Niemann-Pick type A, a disease caused by a deficiency of ASM activity resulting in SM accumulation. Furthermore, the addition of SM to cultured cells also increased WNV infection, whereas treatment with pharmacological inhibitors of SM synthesis reduced WNV infection. Confocal microscopy analyses confirmed the association of SM with viral replication sites within infected cells. Our results unveil that SM metabolism regulates flavivirus infection in vivo and propose SM as a suitable target for antiviral design against WNV.

  8. West Nile Virus in Resident Birds from Yucatan, Mexico.

    Science.gov (United States)

    Chaves, Andrea; Sotomayor-Bonilla, Jesus; Monge, Otto; Ramírez, Abigaíl; Galindo, Francisco; Sarmiento-Silva, Rosa Elena; Gutiérrez-Espeleta, Gustavo A; Suzán, Gerardo

    2016-01-01

    West Nile virus (WNV) in the Americas is thought to be transported at large spatial scales by migratory birds and locally spread and amplified by resident birds. Local processes, including interspecific interactions and dominance of passerine species recognized as competent reservoirs, may boost infection and maintain endemic cycles. Change in species composition has been recognized as an important driver for infection dynamics. Due to migration and changes in species diversity and composition in wintering grounds, changes in infection prevalence are expected. To these changes, we used PCR to estimate the prevalence of WNV in wild resident birds during the dry and rainy seasons of 2012 in Yucatan, Mexico. Serum samples were obtained from 104 wild birds, belonging to six orders and 35 species. We detected WNV in 14 resident birds, representing 11 species and three orders. Prevalences by order was Passeriformes (27%), Columbiformes (6%), and Piciformes (33%). Resident birds positive to WNV from Yucatan may be indicative of local virus circulation and evidence of past virus transmission activity.

  9. Evaluating the Use of Commercial West Nile Virus Antigens as Positive Controls in the Rapid Analyte Measurement Platform West Nile Virus Assay.

    Science.gov (United States)

    Burkhalter, Kristen L; Savage, Harry M

    2015-12-01

    We evaluated the utility of 2 types of commercially available antigens as positive controls in the Rapid Analyte Measurement Platform (RAMP®) West Nile virus (WNV) assay. Purified recombinant WNV envelope antigens and whole killed virus antigens produced positive RAMP results and either type would be useful as a positive control. Killed virus antigens provide operational and economic advantages and we recommend their use over purified recombinant antigens. We also offer practical applications for RAMP positive controls and recommendations for preparing them. PMID:26675461

  10. Evaluating the Use of Commercial West Nile Virus Antigens as Positive Controls in the Rapid Analyte Measurement Platform West Nile Virus Assay.

    Science.gov (United States)

    Burkhalter, Kristen L; Savage, Harry M

    2015-12-01

    We evaluated the utility of 2 types of commercially available antigens as positive controls in the Rapid Analyte Measurement Platform (RAMP®) West Nile virus (WNV) assay. Purified recombinant WNV envelope antigens and whole killed virus antigens produced positive RAMP results and either type would be useful as a positive control. Killed virus antigens provide operational and economic advantages and we recommend their use over purified recombinant antigens. We also offer practical applications for RAMP positive controls and recommendations for preparing them.

  11. Molecularly engineered live-attenuated chimeric West Nile/dengue virus vaccines protect rhesus monkeys from West Nile virus

    International Nuclear Information System (INIS)

    Two molecularly engineered, live-attenuated West Nile virus (WN) vaccine candidates were highly attenuated and protective in rhesus monkeys. The vaccine candidates are chimeric viruses (designated WN/DEN4) bearing the membrane precursor and envelope protein genes of WN on a backbone of dengue 4 virus (DEN4) with or without a deletion of 30 nucleotides (Δ30) in the 3' noncoding region of DEN4. Viremia in WN/DEN4- infected monkeys was reduced 100-fold compared to that in WN- or DEN4-infected monkeys. WN/DEN4-3'Δ30 did not cause detectable viremia, indicating that it is even more attenuated for monkeys. These findings indicate that chimerization itself and the presence of the Δ30 mutation independently contribute to the attenuation phenotype for nonhuman primates. Despite their high level of attenuation in monkeys, the chimeras induced a moderate-to-high titer of neutralizing antibodies and prevented viremia in monkeys challenged with WN. The more attenuated vaccine candidate, WN/DEN4-3'Δ30, will be evaluated first in our initial clinical studies

  12. Crystal Structure of West Nile Virus Envelope Glycoprotein Reveals Viral Surface Epitopes

    Energy Technology Data Exchange (ETDEWEB)

    Kanai,R.; Kar, K.; Anthony, K.; Gould, L.; Ledizet, M.; Fikrig, E.; Marasco, W.; Koski, R.; Modis, Y.

    2006-01-01

    West Nile virus, a member of the Flavivirus genus, causes fever that can progress to life-threatening encephalitis. The major envelope glycoprotein, E, of these viruses mediates viral attachment and entry by membrane fusion. We have determined the crystal structure of a soluble fragment of West Nile virus E. The structure adopts the same overall fold as that of the E proteins from dengue and tick-borne encephalitis viruses. The conformation of domain II is different from that in other prefusion E structures, however, and resembles the conformation of domain II in postfusion E structures. The epitopes of neutralizing West Nile virus-specific antibodies map to a region of domain III that is exposed on the viral surface and has been implicated in receptor binding. In contrast, we show that certain recombinant therapeutic antibodies, which cross-neutralize West Nile and dengue viruses, bind a peptide from domain I that is exposed only during the membrane fusion transition. By revealing the details of the molecular landscape of the West Nile virus surface, our structure will assist the design of antiviral vaccines and therapeutics.

  13. Autonomic nervous dysfunction in hamsters infected with West Nile virus.

    Directory of Open Access Journals (Sweden)

    Hong Wang

    Full Text Available Clinical studies and case reports clearly document that West Nile virus (WNV can cause respiratory and gastrointestinal (GI complications. Other functions controlled by the autonomic nervous system may also be directly affected by WNV, such as bladder and cardiac functions. To investigate how WNV can cause autonomic dysfunctions, we focused on the cardiac and GI dysfunctions of rodents infected with WNV. Infected hamsters had distension of the stomach and intestines at day 9 after viral challenge. GI motility was detected by a dye retention assay; phenol red dye was retained more in the stomachs of infected hamsters as compared to sham-infected hamsters. The amplitudes of electromygraphs (EMGs of intestinal muscles were significantly reduced. Myenteric neurons that innervate the intestines, in addition to neurons in the brain stem, were identified to be infected with WNV. These data suggest that infected neurons controlling autonomic function were the cause of GI dysfunction in WNV-infected hamsters. Using radiotelemetry to record electrocardiograms and to measure heart rate variability (HRV, a well-accepted readout for autonomic function, we determined that HRV and autonomic function were suppressed in WNV-infected hamsters. Cardiac histopathology was observed at day 9 only in the right atrium, which was coincident with WNV staining. A subset of WNV infected cells was identified among cells with hyperpolarization-activated cyclic nucleotide-gated potassium channel 4 (HCN4 as a marker for cells in the sinoatrial (SA and atrioventricular (AV nodes. The unique contribution of this study is the discovery that WNV infection of hamsters can lead to autonomic dysfunction as determined by reduced HRV and reduced EMG amplitudes of the GI tract. These data may model autonomic dysfunction of the human West Nile neurological disease.

  14. Differential Virulence and Pathogenesis of West Nile Viruses

    Directory of Open Access Journals (Sweden)

    Emilie Donadieu

    2013-11-01

    Full Text Available West Nile virus (WNV is a neurotropic flavivirus that cycles between mosquitoes and birds but that can also infect humans, horses, and other vertebrate animals. In most humans, WNV infection remains subclinical. However, 20%–40% of those infected may develop WNV disease, with symptoms ranging from fever to meningoencephalitis. A large variety of WNV strains have been described worldwide. Based on their genetic differences, they have been classified into eight lineages; the pathogenic strains belong to lineages 1 and 2. Ten years ago, Beasley et al. (2002 found that dramatic differences exist in the virulence and neuroinvasion properties of lineage 1 and lineage 2 WNV strains. Further insights on how WNV interacts with its hosts have recently been gained; the virus acts either at the periphery or on the central nervous system (CNS, and these observed differences could help explain the differential virulence and neurovirulence of WNV strains. This review aims to summarize the current state of knowledge on factors that trigger WNV dissemination and CNS invasion as well as on the inflammatory response and CNS damage induced by WNV. Moreover, we will discuss how WNV strains differentially interact with the innate immune system and CNS cells, thus influencing WNV pathogenesis.

  15. The natural history of West Nile virus infection presenting with West Nile virus meningoencephalitis in a man with a prolonged illness: a case report

    Directory of Open Access Journals (Sweden)

    Wood James B

    2011-05-01

    Full Text Available Abstract Introduction Estimates indicate that West Nile virus infects approximately one and a half million people in the United States of America. Up to 1% may develop West Nile virus neuroinvasive disease, in which infected patients develop any combination of meningitis, encephalitis, or acute paralysis. Case presentation A 56-year-old African-American man presented to our hospital with headache, restlessness, fever, myalgias, decreased appetite, and progressive confusion. A cerebrospinal fluid examination showed mild leukocytosis and an elevated protein level. Testing for routine infections was negative. Brain T2-weighted magnetic resonance imaging scans showed marked enlargement of caudate nuclei and increased intensity within the basal ganglia and thalami. A West Nile virus titer was positive, and serial brain magnetic resonance imaging scans showed resolving abnormalities that paralleled his neurological examination. Conclusion This report is unusual as it portrays the natural history and long-term consequences of West Nile virus meningoencephalitis diagnosed on the basis of serial brain images.

  16. Purification and crystallization of dengue and West Nile virus NS2B–NS3 complexes

    International Nuclear Information System (INIS)

    Crystals of dengue serotype 2 and West Nile virus NS2B–NS3 protease complexes have been obtained and the crystals of both diffract to useful resolution. Sample homogeneity was essential for obtaining X-ray-quality crystals of the dengue protease. Controlled proteolysis produced a crystallizable fragment of the apo West Nile virus NS2B–NS3 and crystals were also obtained in the presence of a peptidic inhibitor. Both dengue and West Nile virus infections are an increasing risk to humans, not only in tropical and subtropical areas, but also in North America and parts of Europe. These viral infections are generally transmitted by mosquitoes, but may also be tick-borne. Infection usually results in mild flu-like symptoms, but can also cause encephalitis and fatalities. Approximately 2799 severe West Nile virus cases were reported this year in the United States, resulting in 102 fatalities. With this alarming increase in the number of West Nile virus infections in western countries and the fact that dengue virus already affects millions of people per year in tropical and subtropical climates, there is a real need for effective medicines. A possible therapeutic target to combat these viruses is the protease, which is essential for virus replication. In order to provide structural information to help to guide a lead identification and optimization program, crystallizations of the NS2B–NS3 protease complexes from both dengue and West Nile viruses have been initiated. Crystals that diffract to high resolution, suitable for three-dimensional structure determinations, have been obtained

  17. Purification and crystallization of dengue and West Nile virus NS2B–NS3 complexes

    Energy Technology Data Exchange (ETDEWEB)

    D’Arcy, Allan, E-mail: allan.darcy@novartis.com; Chaillet, Maxime; Schiering, Nikolaus; Villard, Frederic [Novartis Institutes of Biomedical Research, Protease Platform, Klybeckstrasse 144, CH 4002 Basel (Switzerland); Lim, Siew Pheng [Novartis Institutes of Tropical Diseases (Singapore); Lefeuvre, Peggy [Novartis Institutes of Biomedical Research, Protease Platform, Klybeckstrasse 144, CH 4002 Basel (Switzerland); Erbel, Paul [Novartis Institutes of Biomedical Research, Protease Platform, Klybeckstrasse 144, CH 4002 Basel (Switzerland); Novartis Institutes of Tropical Diseases (Singapore)

    2006-02-01

    Crystals of dengue serotype 2 and West Nile virus NS2B–NS3 protease complexes have been obtained and the crystals of both diffract to useful resolution. Sample homogeneity was essential for obtaining X-ray-quality crystals of the dengue protease. Controlled proteolysis produced a crystallizable fragment of the apo West Nile virus NS2B–NS3 and crystals were also obtained in the presence of a peptidic inhibitor. Both dengue and West Nile virus infections are an increasing risk to humans, not only in tropical and subtropical areas, but also in North America and parts of Europe. These viral infections are generally transmitted by mosquitoes, but may also be tick-borne. Infection usually results in mild flu-like symptoms, but can also cause encephalitis and fatalities. Approximately 2799 severe West Nile virus cases were reported this year in the United States, resulting in 102 fatalities. With this alarming increase in the number of West Nile virus infections in western countries and the fact that dengue virus already affects millions of people per year in tropical and subtropical climates, there is a real need for effective medicines. A possible therapeutic target to combat these viruses is the protease, which is essential for virus replication. In order to provide structural information to help to guide a lead identification and optimization program, crystallizations of the NS2B–NS3 protease complexes from both dengue and West Nile viruses have been initiated. Crystals that diffract to high resolution, suitable for three-dimensional structure determinations, have been obtained.

  18. West Nile virus isolated from a Virginia opossum (Didelphis virginiana) in northwestern Missouri, USA, 2012.

    Science.gov (United States)

    Bosco-Lauth, Angela; Harmon, Jessica R; Lash, R Ryan; Weiss, Sonja; Langevin, Stanley; Savage, Harry M; Godsey, Marvin S; Burkhalter, Kristen; Root, J Jeffrey; Gidlewski, Thomas; Nicholson, William L; Brault, Aaron C; Komar, Nicholas

    2014-10-01

    We describe the isolation of West Nile virus (WNV; Flaviviridae, Flavivirus) from blood of a Virginia opossum (Didelphis virginiana) collected in northwestern Missouri, USA in August 2012. Sequencing determined that the virus was related to lineage 1a WNV02 strains. We discuss the role of wildlife in WNV disease epidemiology. PMID:25098303

  19. Vector competence of the stable fly (Diptera: Muscidae)for West Nile virus.

    Science.gov (United States)

    Stable flies, which are notorious pests of cattle and other livestock, were suspected of transmitting West Nile virus (WNV) among American white pelicans at the Medicine Lake Wildlife Refuge in northeastern Montana in 2006-2007. However the ability of stable flies to transmit the virus was unknown. ...

  20. West Nile virus associations in wild mammals: a synthesis.

    Science.gov (United States)

    Jeffrey Root, J

    2013-04-01

    Exposures to West Nile virus (WNV) have been documented in a variety of wild mammals in both the New and Old Worlds. This review tabulates at least 100 mammal species with evidence of WNV exposure. Many of these exposures were detected in free-ranging mammals, while several were noted in captive individuals. In addition to exposures, this review discusses experimental infections in terms of the potential for reservoir competence of select wild mammal species. Overall, few experimental infections have been conducted on wild mammals. As such, the role of most wild mammals as potential amplifying hosts for WNV is, to date, uncertain. In most instances, experimental infections of wild mammals with WNV have resulted in no or low-level viremia. Some recent studies have indicated that certain species of tree squirrels (Sciurus spp.), eastern chipmunks (Tamias striatus), and eastern cottontail rabbits (Sylvilagus floridanus) develop viremia sufficient for infecting some mosquito species. Certain mammalian species, such as tree squirrels, mesopredators, and deer have been suggested as useful species for WNV surveillance. In this review article, the information pertaining to wild mammal associations with WNV is synthesized. PMID:23212739

  1. Economic conditions predict prevalence of West Nile virus.

    Directory of Open Access Journals (Sweden)

    Ryan J Harrigan

    Full Text Available Understanding the conditions underlying the proliferation of infectious diseases is crucial for mitigating future outbreaks. Since its arrival in North America in 1999, West Nile virus (WNV has led to population-wide declines of bird species, morbidity and mortality of humans, and expenditures of millions of dollars on treatment and control. To understand the environmental conditions that best explain and predict WNV prevalence, we employed recently developed spatial modeling techniques in a recognized WNV hotspot, Orange County, California. Our models explained 85-95% of the variation of WNV prevalence in mosquito vectors, and WNV presence in secondary human hosts. Prevalence in both vectors and humans was best explained by economic variables, specifically per capita income, and by anthropogenic characteristics of the environment, particularly human population and neglected swimming pool density. While previous studies have shown associations between anthropogenic change and pathogen presence, results show that poorer economic conditions may act as a direct surrogate for environmental characteristics related to WNV prevalence. Low-income areas may be associated with higher prevalence for a number of reasons, including variations in property upkeep, microhabitat conditions conducive to viral amplification in both vectors and hosts, host community composition, and human behavioral responses related to differences in education or political participation. Results emphasize the importance and utility of including economic variables in mapping spatial risk assessments of disease.

  2. MATHEMATICAL ANALYSIS OF WEST NILE VIRUS MODEL WITH DISCRETE DELAYS

    Institute of Scientific and Technical Information of China (English)

    Salisu M. GARBA; Mohammad A. SAFI

    2013-01-01

    The paper presents the basic model for the transmission dynamics of West Nile virus (WNV). The model, which consists of seven mutually-exclusive compartments representing the birds and vector dynamics, has a locally-asymptotically stable disease-free equilibrium whenever the associated reproduction number (R0) is less than unity. As reveal in [3, 20], the analyses of the model show the existence of the phenomenon of backward bifurcation (where the stable disease-free equilibrium of the model co-exists with a stable endemic equilibrium when the reproduction number of the disease is less than unity). It is shown, that the backward bifurcation phenomenon can be removed by substituting the associated standard incidence function with a mass action incidence. Analysis of the reproduction number of the model shows that, the disease will persist, whenever R0 >1, and increase in the length of incubation period can help reduce WNV burden in the community if a certain threshold quantities, denoted by ∆b and ∆v are negative. On the other hand, increasing the length of the incubation period increases disease burden if∆b>0 and ∆v >0. Furthermore, it is shown that adding time delay to the corresponding autonomous model with standard incidence (considered in [2]) does not alter the qualitative dynamics of the autonomous system (with respect to the elimination or persistence of the disease).

  3. Does reservoir host mortality enhance transmission of West Nile virus?

    Directory of Open Access Journals (Sweden)

    Foppa Ivo M

    2007-05-01

    Full Text Available Abstract Background Since its 1999 emergence in New York City, West Nile virus (WNV has become the most important and widespread cause of mosquito-transmitted disease in North America. Its sweeping spread from the Atlantic to the Pacific coast was accompanied by widespread mortality among wild birds, especially corvids. Only sporadic avian mortality had previously been associated with this infection in the Old World. Here, we examine the possibility that reservoir host mortality may intensify transmission, both by concentrating vector mosquitoes on remaining hosts and by preventing the accumulation of "herd immunity". Results Inspection of the Ross-Macdonald expression of the basic reproductive number (R0 suggests that this quantity may increase with reservoir host mortality. Computer simulation confirms this finding and indicates that the level of virulence is positively associated with the numbers of infectious mosquitoes by the end of the epizootic. The presence of reservoir incompetent hosts in even moderate numbers largely eliminated the transmission-enhancing effect of host mortality. Local host die-off may prevent mosquitoes to "waste" infectious blood meals on immune host and may thus facilitate perpetuation and spread of transmission. Conclusion Under certain conditions, host mortality may enhance transmission of WNV and similarly maintained arboviruses and thus facilitate their emergence and spread. The validity of the assumptions upon which this argument is built need to be empirically examined.

  4. West Nile virus vector Culex modestus established in southern England

    Directory of Open Access Journals (Sweden)

    Golding Nick

    2012-02-01

    Full Text Available Abstract Background The risk posed to the United Kingdom by West Nile virus (WNV has previously been considered low, due to the absence or scarcity of the main Culex sp. bridge vectors. The mosquito Culex modestus is widespread in southern Europe, where it acts as the principle bridge vector of WNV. This species was not previously thought to be present in the United Kingdom. Findings Mosquito larval surveys carried out in 2010 identified substantial populations of Cx. modestus at two sites in marshland in southeast England. Host-seeking-adult traps placed at a third site indicate that the relative seasonal abundance of Cx. modestus peaks in early August. DNA barcoding of these specimens from the United Kingdom and material from southern France confirmed the morphological identification. Conclusions Cx. modestus appears to be established in the North Kent Marshes, possibly as the result of a recent introduction. The addition of this species to the United Kingdom's mosquito fauna may increase the risk posed to the United Kingdom by WNV.

  5. Crystallization and preliminary X-ray diffraction analysis of West Nile virus

    International Nuclear Information System (INIS)

    Crystals of infectious West Nile virus were obtained and diffracted at best to about 25 Å resolution. Preliminary analysis of the diffraction pattern suggested tight hexagonal packing of the intact virus. West Nile virus, a human pathogen, is closely related to other medically important flaviviruses of global impact such as dengue virus. The infectious virus was purified from cell culture using polyethylene glycol (PEG) precipitation and density-gradient centrifugation. Thin amorphously shaped crystals of the lipid-enveloped virus were grown in quartz capillaries equilibrated by vapor diffusion. Crystal diffraction extended at best to a resolution of about 25 Å using synchrotron radiation. A preliminary analysis of the diffraction images indicated that the crystals had unit-cell parameters a ≃ b ≃ 480 Å, γ = 120°, suggesting a tight hexagonal packing of one virus particle per unit cell

  6. First isolation of West Nile virus from a dromedary camel.

    Science.gov (United States)

    Joseph, Sunitha; Wernery, Ulrich; Teng, Jade Ll; Wernery, Renate; Huang, Yi; Patteril, Nissy Ag; Chan, Kwok-Hung; Elizabeth, Shyna K; Fan, Rachel Yy; Lau, Susanna Kp; Kinne, Jörg; Woo, Patrick Cy

    2016-01-01

    Although antibodies against West Nile virus (WNV) have been detected in the sera of dromedaries in the Middle East, North Africa and Spain, no WNV has been isolated or amplified from dromedary or Bactrian camels. In this study, WNV was isolated from Vero cells inoculated with both nasal swab and pooled trachea/lung samples from a dromedary calf in Dubai. Complete-genome sequencing and phylogenetic analysis using the near-whole-genome polyprotein revealed that the virus belonged to lineage 1a. There was no clustering of the present WNV with other WNVs isolated in other parts of the Middle East. Within lineage 1a, the dromedary WNV occupied a unique position, although it was most closely related to other WNVs of cluster 2. Comparative analysis revealed that the putative E protein encoded by the genome possessed the original WNV E protein glycosylation motif NYS at E154-156, which contained the N-linked glycosylation site at N-154 associated with increased WNV pathogenicity and neuroinvasiveness. In the putative NS1 protein, the A70S substitution observed in other cluster 2 WNVs and P250, which has been implicated in neuroinvasiveness, were present. In addition, the foo motif in the putative NS2A protein, which has been implicated in neuroinvasiveness, was detected. Notably, the amino-acid residues at 14 positions in the present dromedary WNV genome differed from those in most of the closely related WNV strains in cluster 2 of lineage 1a, with the majority of these differences observed in the putative E and NS5 proteins. The present study is the first to demonstrate the isolation of WNV from dromedaries. This finding expands the possible reservoirs of WNV and sources of WNV infection. PMID:27273223

  7. Conservation and variability of West Nile virus proteins.

    Directory of Open Access Journals (Sweden)

    Qi Ying Koo

    Full Text Available West Nile virus (WNV has emerged globally as an increasingly important pathogen for humans and domestic animals. Studies of the evolutionary diversity of the virus over its known history will help to elucidate conserved sites, and characterize their correspondence to other pathogens and their relevance to the immune system. We describe a large-scale analysis of the entire WNV proteome, aimed at identifying and characterizing evolutionarily conserved amino acid sequences. This study, which used 2,746 WNV protein sequences collected from the NCBI GenPept database, focused on analysis of peptides of length 9 amino acids or more, which are immunologically relevant as potential T-cell epitopes. Entropy-based analysis of the diversity of WNV sequences, revealed the presence of numerous evolutionarily stable nonamer positions across the proteome (entropy value of < or = 1. The representation (frequency of nonamers variant to the predominant peptide at these stable positions was, generally, low (< or = 10% of the WNV sequences analyzed. Eighty-eight fragments of length 9-29 amino acids, representing approximately 34% of the WNV polyprotein length, were identified to be identical and evolutionarily stable in all analyzed WNV sequences. Of the 88 completely conserved sequences, 67 are also present in other flaviviruses, and several have been associated with the functional and structural properties of viral proteins. Immunoinformatic analysis revealed that the majority (78/88 of conserved sequences are potentially immunogenic, while 44 contained experimentally confirmed human T-cell epitopes. This study identified a comprehensive catalogue of completely conserved WNV sequences, many of which are shared by other flaviviruses, and majority are potential epitopes. The complete conservation of these immunologically relevant sequences through the entire recorded WNV history suggests they will be valuable as components of peptide-specific vaccines or other

  8. First isolation of West Nile virus from a dromedary camel

    Science.gov (United States)

    Joseph, Sunitha; Wernery, Ulrich; Teng, Jade LL; Wernery, Renate; Huang, Yi; Patteril, Nissy AG; Chan, Kwok-Hung; Elizabeth, Shyna K; Fan, Rachel YY; Lau, Susanna KP; Kinne, Jörg; Woo, Patrick CY

    2016-01-01

    Although antibodies against West Nile virus (WNV) have been detected in the sera of dromedaries in the Middle East, North Africa and Spain, no WNV has been isolated or amplified from dromedary or Bactrian camels. In this study, WNV was isolated from Vero cells inoculated with both nasal swab and pooled trachea/lung samples from a dromedary calf in Dubai. Complete-genome sequencing and phylogenetic analysis using the near-whole-genome polyprotein revealed that the virus belonged to lineage 1a. There was no clustering of the present WNV with other WNVs isolated in other parts of the Middle East. Within lineage 1a, the dromedary WNV occupied a unique position, although it was most closely related to other WNVs of cluster 2. Comparative analysis revealed that the putative E protein encoded by the genome possessed the original WNV E protein glycosylation motif NYS at E154–156, which contained the N-linked glycosylation site at N-154 associated with increased WNV pathogenicity and neuroinvasiveness. In the putative NS1 protein, the A70S substitution observed in other cluster 2 WNVs and P250, which has been implicated in neuroinvasiveness, were present. In addition, the foo motif in the putative NS2A protein, which has been implicated in neuroinvasiveness, was detected. Notably, the amino-acid residues at 14 positions in the present dromedary WNV genome differed from those in most of the closely related WNV strains in cluster 2 of lineage 1a, with the majority of these differences observed in the putative E and NS5 proteins. The present study is the first to demonstrate the isolation of WNV from dromedaries. This finding expands the possible reservoirs of WNV and sources of WNV infection. PMID:27273223

  9. Seroprevalence of St. Louis encephalitis virus and West Nile virus (Flavivirus, Flaviviridae) in horses, Uruguay.

    Science.gov (United States)

    Burgueño, Analía; Spinsanti, Lorena; Díaz, Luis Adrián; Rivarola, María Elisa; Arbiza, Juan; Contigiani, Marta; Delfraro, Adriana

    2013-01-01

    St. Louis encephalitis virus (SLEV) and West Nile virus (WNV) belong to the Japanese encephalitis antigenic complex (Flavivirus genus, Flaviviridae family). They show antigenic close relationships and share many similarities in their ecology. Both are responsible for serious human diseases. The aim of this study was to investigate the presence of neutralizing antibodies to these viruses in horses from Uruguay. To do this, 425 horse sera were collected in 2007 and analyzed by plaque reduction neutralization tests. As a result, 205 sera (48.2%) were found positive for SLEV, with titers ranging between 10 and 80. Two sera remained inconclusive, since they showed low titers to WNV and SLEV (10 and 20), not allowing us to demonstrate activity of WNV in our territory. This is the first report of circulation of SLEV in horses in Uruguay.

  10. A nano-view of West Nile virus-induced cellular changes during infection

    Directory of Open Access Journals (Sweden)

    Ng Mah-Lee

    2004-06-01

    Full Text Available Abstract Background Microscopic imaging of viruses and their interactions with and effects on host cells are frequently held back by limitations of the microscope's resolution or the invasive nature of the sample preparation procedures. It is also difficult to have a technique that would allow simultaneous imaging of both surface and sub-surface on the same cell. This has hampered endeavours to elucidate virus-host interactions. Atomic Force Microscopy (AFM, which is commonly used in the physical sciences, is now becoming a good correlative form of microscopy used to complement existing optical, confocal and electron microscopy for biological applications Results In this study, the West Nile (Sarafend virus-infected Vero cell model was used. The atomic force microscope was found to be useful in producing high resolution images of virus-host events with minimal sample processing requirements. The AFM was able to image the budding of the West Nile (Sarafend virus at the infected cell surface. Proliferation of the filopodia and thickening of clusters of actin filaments accompanied West Nile virus replication. Conclusions The study shows that the AFM is useful for virus-host interaction studies. The technique provides morphological information on both the virus and the host cell during the infection stages.

  11. West Nile Virus RNA in Tissues from Donor Associated with Transmission to Organ Transplant Recipients

    Centers for Disease Control (CDC) Podcasts

    2013-11-19

    William Hale reads an abridged version of the Emerging Infectious Diseases’ dispatch, West Nile Virus RNA in Tissues from Donor Associated with Transmission to Organ Transplant Recipients.  Created: 11/19/2013 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 11/21/2013.

  12. Human Monoclonal Antibodies against West Nile Virus Induced by Natural Infection Neutralize at a Postattachment Step

    NARCIS (Netherlands)

    Vogt, Matthew R.; Moesker, Bastiaan; Goudsmit, Jaap; Jongeneelen, Mandy; Austin, S. Kyle; Oliphant, Theodore; Nelson, Steevenson; Pierson, Theodore C.; Wilschut, Jan; Throsby, Mark; Diamond, Michael S.

    2009-01-01

    West Nile virus (WNV) is a neurotropic flavivirus that is now a primary cause of epidemic encephalitis in North America. Studies of mice have demonstrated that the humoral immune response against WNV limits primary infection and protects against a secondary challenge. The most-potent neutralizing mo

  13. Spatially Explicit West Nile Virus Risk Modeling in Santa Clara County, CA

    Science.gov (United States)

    A geographic information systems model designed to identify regions of West Nile virus (WNV) transmission risk was tested and calibrated with data collected in Santa Clara County, California. American Crows that died from WNV infection in 2005, provided spatial and temporal ground truth. When the mo...

  14. Detecting West Nile Virus in Owls and Raptors by an Antigen-capture Assay

    OpenAIRE

    Gancz, Ady Y.; Campbell, Douglas G.; Barker, Ian K; Lindsay, Robbin; Hunter, Bruce

    2004-01-01

    We evaluated a rapid antigen-capture assay (VecTest) for detection of West Nile virus in oropharyngeal and cloacal swabs, collected at necropsy from owls (N = 93) and raptors (N = 27). Sensitivity was 93.5%–95.2% for northern owl species but

  15. Vector competence of selected North American Culex and Coquillettidia mosquitoes for West Nile virus.

    OpenAIRE

    Sardelis, M. R.; Turell, M.J.; Dohm, D. J.; O'Guinn, M. L.

    2001-01-01

    To control West Nile virus (WNV), it is necessary to know which mosquitoes are able to transmit this virus. Therefore, we evaluated the WNV vector potential of several North American mosquito species. Culex restuans and Cx. salinarius, two species from which WNV was isolated in New York in 2000, were efficient laboratory vectors. Cx. quinquefasciatus and Cx. nigripalpus from Florida were competent but only moderately efficient vectors. Coquillettidia perturbans was an inefficient laboratory v...

  16. On the potential roles of ticks and migrating birds in the ecology of West Nile virus

    OpenAIRE

    Hagman, Karl; Barboutis, Christos; Ehrenborg, Christian; Fransson, Thord; Thomas G.T. Jaenson; Lindgren, Per-Eric; Lundkvist, Åke; Nyström, Fredrik; Waldenström, Jonas; Salaneck, Erik

    2014-01-01

    Background: Mosquitoes are the primary vectors of West Nile virus (WNV). Ticks have, however, been suggested to be potential reservoirs of WNV. In order to investigate their role in the spread of the virus, ticks, which had been collected from birds migrating northwards from Africa to Europe, were analyzed for the potential presence of WNV-RNA.Methods: On the Mediterranean islands Capri and Antikythira a total of 14,824 birds were captured and investigated from which 747 ticks were collected....

  17. Detection and sequencing of West Nile virus RNA from human urine and serum samples during the 2014 seasonal period.

    Science.gov (United States)

    Nagy, Anna; Bán, Enikő; Nagy, Orsolya; Ferenczi, Emőke; Farkas, Ágnes; Bányai, Krisztián; Farkas, Szilvia; Takács, Mária

    2016-07-01

    West Nile virus, a widely distributed mosquito-borne flavivirus, is responsible for numerous animal and human infections in Europe, Africa and the Americas. In Hungary, the average number of human infections falls between 10 and 20 cases each year. The severity of clinically manifesting infections varies widely from the milder form of West Nile fever to West Nile neuroinvasive disease (WNND). In routine laboratory diagnosis of human West Nile virus infections, serological methods are mainly applied due to the limited duration of viremia. However, recent studies suggest that detection of West Nile virus RNA in urine samples may be useful as a molecular diagnostic test for these infections. The Hungarian National Reference Laboratory for Viral Zoonoses serologically confirmed eleven acute human infections during the 2014 seasonal period. In three patients with neurological symptoms, viral RNA was detected from both urine and serum specimens, albeit for a longer period and in higher copy numbers with urine. Phylogenetic analysis of the NS3 genomic region of three strains and the complete genome of one selected strain demonstrated that all three patients had lineage-2 West Nile virus infections. Our findings reaffirm the utility of viral RNA detection in urine as a molecular diagnostic procedure for diagnosis of West Nile virus infections. PMID:27038827

  18. Detection and sequencing of West Nile virus RNA from human urine and serum samples during the 2014 seasonal period.

    Science.gov (United States)

    Nagy, Anna; Bán, Enikő; Nagy, Orsolya; Ferenczi, Emőke; Farkas, Ágnes; Bányai, Krisztián; Farkas, Szilvia; Takács, Mária

    2016-07-01

    West Nile virus, a widely distributed mosquito-borne flavivirus, is responsible for numerous animal and human infections in Europe, Africa and the Americas. In Hungary, the average number of human infections falls between 10 and 20 cases each year. The severity of clinically manifesting infections varies widely from the milder form of West Nile fever to West Nile neuroinvasive disease (WNND). In routine laboratory diagnosis of human West Nile virus infections, serological methods are mainly applied due to the limited duration of viremia. However, recent studies suggest that detection of West Nile virus RNA in urine samples may be useful as a molecular diagnostic test for these infections. The Hungarian National Reference Laboratory for Viral Zoonoses serologically confirmed eleven acute human infections during the 2014 seasonal period. In three patients with neurological symptoms, viral RNA was detected from both urine and serum specimens, albeit for a longer period and in higher copy numbers with urine. Phylogenetic analysis of the NS3 genomic region of three strains and the complete genome of one selected strain demonstrated that all three patients had lineage-2 West Nile virus infections. Our findings reaffirm the utility of viral RNA detection in urine as a molecular diagnostic procedure for diagnosis of West Nile virus infections.

  19. Interferon-λ restricts West Nile virus neuroinvasion by tightening the blood-brain barrier.

    Science.gov (United States)

    Lazear, Helen M; Daniels, Brian P; Pinto, Amelia K; Huang, Albert C; Vick, Sarah C; Doyle, Sean E; Gale, Michael; Klein, Robyn S; Diamond, Michael S

    2015-04-22

    Although interferon-λ [also known as type III interferon or interleukin-28 (IL-28)/IL-29] restricts infection by several viruses, its inhibitory mechanism has remained uncertain. We used recombinant interferon-λ and mice lacking the interferon-λ receptor (IFNLR1) to evaluate the effect of interferon-λ on infection with West Nile virus, an encephalitic flavivirus. Cell culture studies in mouse keratinocytes and dendritic cells showed no direct antiviral effect of exogenous interferon-λ, even though expression of interferon-stimulated genes was induced. We observed no differences in West Nile virus burden between wild-type and Ifnlr1(-/-) mice in the draining lymph nodes, spleen, or blood. We detected increased West Nile virus infection in the brain and spinal cord of Ifnlr1(-/-) mice, yet this was not associated with a direct antiviral effect in mouse neurons. Instead, we observed an increase in blood-brain barrier permeability in Ifnlr1(-/-) mice. Treatment of mice with pegylated interferon-λ2 resulted in decreased blood-brain barrier permeability, reduced West Nile virus infection in the brain without affecting viremia, and improved survival against lethal virus challenge. An in vitro model of the blood-brain barrier showed that interferon-λ signaling in mouse brain microvascular endothelial cells increased transendothelial electrical resistance, decreased virus movement across the barrier, and modulated tight junction protein localization in a protein synthesis- and signal transducer and activator of transcription 1 (STAT1)-independent manner. Our data establish an indirect antiviral function of interferon-λ in which noncanonical signaling through IFNLR1 tightens the blood-brain barrier and restricts viral neuroinvasion and pathogenesis.

  20. Prevalence of West Nile virus in Mashhad, Iran:A population-based study

    Institute of Scientific and Technical Information of China (English)

    Zahra Meshkat; Sadegh Chinikar; MohammadTaghi Shakeri; Lida Manavifar; Maryam Moradi; Hessam Mirshahabi; Tahmineh Jalali; Sahar Khakifirouz; Nariman Shahhosseini

    2015-01-01

    Objective:To evaluate the prevalence of West Nile virus seropositivity in the general population of Mashhad, Northeast of Iran.Methods:One hundred and eighty two individuals living in the city of Mashhad were studied using cluster sampling method. Both IgM and IgG antibodies against WNV were detected by ELISA method.Results:In this study, the overall IgG seroprevalence of positive West Nile virus was 11%; however, IgM antibody was not found in the participants.Conclusions:Our study suggested that the prevalence rate of West virus is considerable in Mashhad city. It seems necessary for clinicians and health care workers to be aware of WNV infection in the Northeast Iran.

  1. Occurrence of West Nile Virus Antibodies in Wild Birds, Horses, and Humans in Poland

    Directory of Open Access Journals (Sweden)

    Jowita Samanta Niczyporuk

    2015-01-01

    Full Text Available Serum samples of 474 wild birds, 378 horses, and 42 humans with meningitis and lymphocytic meningitis were collected between 2010 and 2014 from different areas of Poland. West Nile virus (WNV antibodies were detected using competition enzyme linked immunosorbent assays: ELISA-1 ID Screen West Nile Competition, IDvet, ELISA-2 ID Screen West Nile IgM Capture, and ELISA-3 Ingezim West Nile Compac. The antibodies were found in 63 (13.29% out of 474 wild bird serum samples and in one (0.26% out of 378 horse serum samples. Fourteen (33.33% out of 42 sera from patients were positive against WNV antigen and one serum was doubtful. Positive samples obtained in birds were next retested with virus microneutralisation test to confirm positive results and cross-reactions with other antigens of the Japanese encephalitis complex. We suspect that positive serological results in humans, birds, and horses indicate that WNV can be somehow closely related with the ecosystem in Poland.

  2. Occurrence of West Nile Virus Antibodies in Wild Birds, Horses, and Humans in Poland

    Science.gov (United States)

    Niczyporuk, Jowita Samanta; Samorek-Salamonowicz, Elżbieta; Lecollinet, Sylvie; Pancewicz, Sławomir Andrzej; Kozdruń, Wojciech; Czekaj, Hanna

    2015-01-01

    Serum samples of 474 wild birds, 378 horses, and 42 humans with meningitis and lymphocytic meningitis were collected between 2010 and 2014 from different areas of Poland. West Nile virus (WNV) antibodies were detected using competition enzyme linked immunosorbent assays: ELISA-1 ID Screen West Nile Competition, IDvet, ELISA-2 ID Screen West Nile IgM Capture, and ELISA-3 Ingezim West Nile Compac. The antibodies were found in 63 (13.29%) out of 474 wild bird serum samples and in one (0.26%) out of 378 horse serum samples. Fourteen (33.33%) out of 42 sera from patients were positive against WNV antigen and one serum was doubtful. Positive samples obtained in birds were next retested with virus microneutralisation test to confirm positive results and cross-reactions with other antigens of the Japanese encephalitis complex. We suspect that positive serological results in humans, birds, and horses indicate that WNV can be somehow closely related with the ecosystem in Poland. PMID:25866767

  3. Evaluating red-cockaded woodpeckers for exposure to West Nile Virus and blood parasites

    Science.gov (United States)

    Dusek, R.J.; Richardson, D.; Egstad, K.F.; Heisey, Dennis M.

    2006-01-01

    A marked decline in the Picoides borealis (Red-cockaded Woodpecker [RCW]) population at Noxubee National Wildlife Refuge, MS, was observed in 2002. Demographic changes - including absence of hatch-year birds, decreases in size of known groups, and loss of known groups-were identified during annual fall surveys and are uncharacteristic of RCW populations. In 2003, a serosurvey of 28 adult RCWs was conducted to investigate the presence of West Nile virus (WNV) exposure in the population, possibly providing insight into whether WNV may have been responsible for this decline. Blood smears were also examined from these birds for blood parasites. We found no evidence of West Nile virus exposure or blood parasites in any of the RCWs sampled. Further monitoring of the RCW population and WNV activity in other species at Noxubee NWR is recommended to further evaluate the potential role of WNV and blood parasites in their decline.

  4. Flaviviruses, an expanding threat in public health: focus on Dengue, West Nile, and Japanese encephalitis virus

    OpenAIRE

    Daep, Carlo Amorin; Muñoz-Jordán, Jorge L.; Eugenin, Eliseo Alberto

    2014-01-01

    The flaviviruses Dengue, West Nile, and Japanese encephalitis represent three major mosquito-borne viruses worldwide. These pathogens impact the lives of millions of individuals and potentially could affect non-endemic areas already colonized by mosquito vectors. Unintentional transport of infected vectors (Aedes and Culex sp), traveling within endemic areas, rapid adaptation of the insects into new geographic locations, climate change, and lack of medical surveillance have greatly contribute...

  5. Antibodies to West Nile Virus in Wild and Farmed Crocodiles in Southeastern Mexico

    OpenAIRE

    Machain-Williams, Carlos; Padilla-Paz, Sergio E.; Weber, Manuel; Cetina-Trejo, Rosa; Juarez-Ordaz, José Alfredo; Loroño-Pino, María Alba; Ulloa, Armando; Wang, Chong; Garcia-Rejon, Julián; Blitvich, Bradley J.

    2013-01-01

    Surveillance for evidence of West Nile virus (WNV) infection in Morelet’s crocodiles (Crocodylus moreletii) was conducted in Campeche State, Mexico, in 2007. Sera from 62 crocodiles (32 free-ranging and 30 captive) were assayed for antibodies to WNV by epitope-blocking enzyme-linked immunosorbent assay. Antibodies to WNV were detected in 13 (41%) wild and nine (30%) captive crocodiles, and the overall antibody prevalence was 35%. Although evidence of WNV infection in captive crocodiles has be...

  6. Spatio-temporal patterns of distribution of West Nile virus vectors in eastern Piedmont Region, Italy

    OpenAIRE

    Bisanzio Donal; Giacobini Mario; Bertolotti Luigi; Mosca Andrea; Balbo Luca; Kitron Uriel; Vazquez-Prokopec Gonzalo M

    2011-01-01

    Abstract Background West Nile Virus (WNV) transmission in Italy was first reported in 1998 as an equine outbreak near the swamps of Padule di Fucecchio, Tuscany. No other cases were identified during the following decade until 2008, when horse and human outbreaks were reported in Emilia Romagna, North Italy. Since then, WNV outbreaks have occurred annually, spreading from their initial northern foci throughout the country. Following the outbreak in 1998 the Italian public health authority def...

  7. Temperature, Viral Genetics, and the Transmission of West Nile Virus by Culex pipiens Mosquitoes

    OpenAIRE

    A Marm Kilpatrick; Meola, Mark A.; Moudy, Robin M.; Kramer, Laura D.

    2008-01-01

    The distribution and intensity of transmission of vector-borne pathogens can be strongly influenced by the competence of vectors. Vector competence, in turn, can be influenced by temperature and viral genetics. West Nile virus (WNV) was introduced into the United States of America in 1999 and subsequently spread throughout much of the Americas. Previously, we have shown that a novel genotype of WNV, WN02, first detected in 2001, spread across the US and was more efficient than the introduced ...

  8. Clinical pathology results from cranes with experimental West Nile Virus infection

    Science.gov (United States)

    Olsen, Glenn H.

    2011-01-01

    Sandhill cranes (Grus canadensis) were vaccinated for and then challenged with West Nile virus. Resulting titers demonstrated protection in the vaccinated-challenged cranes as compared to the unvaccinated-challenged cranes. Clinical pathology results showed challenged cranes, whether vaccinated or not, had a decrease in their hematocrits and an elevation of 2.5-fold in their white blood cell counts as compared to unchallenged control sandhill cranes. No differences were apparent in the differential counts of heterophils and lymphocytes.

  9. Statistical Tools for the Interpretation of Enzootic West Nile virus Transmission Dynamics.

    Science.gov (United States)

    Caillouët, Kevin A; Robertson, Suzanne

    2016-01-01

    Interpretation of enzootic West Nile virus (WNV) surveillance indicators requires little advanced mathematical skill, but greatly enhances the ability of public health officials to prescribe effective WNV management tactics. Stepwise procedures for the calculation of mosquito infection rates (IR) and vector index (VI) are presented alongside statistical tools that require additional computation. A brief review of advantages and important considerations for each statistic's use is provided. PMID:27188561

  10. Identifying the environmental conditions favouring West Nile Virus outbreaks in Europe.

    Directory of Open Access Journals (Sweden)

    Matteo Marcantonio

    Full Text Available West Nile Virus (WNV is a globally important mosquito borne virus, with significant implications for human and animal health. The emergence and spread of new lineages, and increased pathogenicity, is the cause of escalating public health concern. Pinpointing the environmental conditions that favour WNV circulation and transmission to humans is challenging, due both to the complexity of its biological cycle, and the under-diagnosis and reporting of epidemiological data. Here, we used remote sensing and GIS to enable collation of multiple types of environmental data over a continental spatial scale, in order to model annual West Nile Fever (WNF incidence across Europe and neighbouring countries. Multi-model selection and inference were used to gain a consensus from multiple linear mixed models. Climate and landscape were key predictors of WNF outbreaks (specifically, high precipitation in late winter/early spring, high summer temperatures, summer drought, occurrence of irrigated croplands and highly fragmented forests. Identification of the environmental conditions associated with WNF outbreaks is key to enabling public health bodies to properly focus surveillance and mitigation of West Nile virus impact, but more work needs to be done to enable accurate predictions of WNF risk.

  11. Production of immunogenic West Nile virus-like particles using a herpes simplex virus 1 recombinant vector.

    Science.gov (United States)

    Taylor, Travis J; Diaz, Fernando; Colgrove, Robert C; Bernard, Kristen A; DeLuca, Neal A; Whelan, Sean P J; Knipe, David M

    2016-09-01

    West Nile virus (WNV) is a flavivirus that swept rapidly across North America in 1999, declined in prevalence, and then resurged in 2012. To date, no vaccine is available to prevent infection in the human population. Herpes simplex virus (HSV) replication-defective vaccine vectors induce a durable immunity characterized by strong antibody and CD8(+) T cell responses even in HSV-immune animals. In this study, a WNV protein expression cassette was optimized for virus-like particle (VLP) production in transfection studies, and the cassette was recombined into an HSV-1 d106-WNV virus vector, which produced extracellular VLPs, as confirmed by immunoelectron microscopy. Immunization of mice with the d106-WNV recombinant vector elicited a specific anti-WNV IgG response. This study highlights the flavivirus coding sequences needed for efficient assembly of virus-like particles. This information will facilitate generation of additional vaccine vectors against other flaviviruses including the recently emerged Zika virus.

  12. Explosive spread of a neuroinvasive lineage 2 West Nile virus in Central Europe, 2008/2009.

    Science.gov (United States)

    Bakonyi, Tamás; Ferenczi, Emőke; Erdélyi, Károly; Kutasi, Orsolya; Csörgő, Tibor; Seidel, Bernhard; Weissenböck, Herbert; Brugger, Katharina; Bán, Enikő; Nowotny, Norbert

    2013-07-26

    For the first time outside sub-Saharan Africa, a lineage 2 West Nile virus (WNV) emerged in Hungary in 2004. It caused sporadic cases of encephalitis in goshawks (Accipiter gentilis), other predatory birds, and in mammals. As a consequence, a surveillance program was initiated in Hungary and in Austria, which included virological, molecular, serological and epidemiological investigations in human beings, birds, horses, and mosquitoes. The virus strain became endemic to Hungary, however only sporadic cases of infections were observed between 2004 and 2007. Unexpectedly, explosive spread of the virus was noted in 2008, when neuroinvasive West Nile disease (WND) was diagnosed all over Hungary in dead goshawks and other birds of prey (n=25), in horses (n=12), and humans (n=22). At the same time this virus also spread to the eastern part of Austria, where it was detected in dead wild birds (n=8). In 2009, recurrent WND outbreaks were observed in Hungary and Austria, in wild birds, horses, and humans in the same areas. Virus isolates of both years exhibited closest genetic relationship to the lineage 2 WNV strain which emerged in 2004. As we know today, the explosive spread of the lineage 2 WNV in 2008 described here remained not restricted to Hungary and Austria, but this virus dispersed further to the south to various Balkan states and reached northern Greece, where it caused the devastating neuroinvasive WND outbreak in humans in 2010.

  13. Explosive spread of a neuroinvasive lineage 2 West Nile virus in Central Europe, 2008/2009.

    Science.gov (United States)

    Bakonyi, Tamás; Ferenczi, Emőke; Erdélyi, Károly; Kutasi, Orsolya; Csörgő, Tibor; Seidel, Bernhard; Weissenböck, Herbert; Brugger, Katharina; Bán, Enikő; Nowotny, Norbert

    2013-07-26

    For the first time outside sub-Saharan Africa, a lineage 2 West Nile virus (WNV) emerged in Hungary in 2004. It caused sporadic cases of encephalitis in goshawks (Accipiter gentilis), other predatory birds, and in mammals. As a consequence, a surveillance program was initiated in Hungary and in Austria, which included virological, molecular, serological and epidemiological investigations in human beings, birds, horses, and mosquitoes. The virus strain became endemic to Hungary, however only sporadic cases of infections were observed between 2004 and 2007. Unexpectedly, explosive spread of the virus was noted in 2008, when neuroinvasive West Nile disease (WND) was diagnosed all over Hungary in dead goshawks and other birds of prey (n=25), in horses (n=12), and humans (n=22). At the same time this virus also spread to the eastern part of Austria, where it was detected in dead wild birds (n=8). In 2009, recurrent WND outbreaks were observed in Hungary and Austria, in wild birds, horses, and humans in the same areas. Virus isolates of both years exhibited closest genetic relationship to the lineage 2 WNV strain which emerged in 2004. As we know today, the explosive spread of the lineage 2 WNV in 2008 described here remained not restricted to Hungary and Austria, but this virus dispersed further to the south to various Balkan states and reached northern Greece, where it caused the devastating neuroinvasive WND outbreak in humans in 2010. PMID:23570864

  14. Crystallization and preliminary X-ray diffraction analysis of West Nile virus

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Barbel; Plevka, Pavel; Kuhn, Richard J.; Rossmann, Michael G. (Purdue)

    2010-05-25

    West Nile virus, a human pathogen, is closely related to other medically important flaviviruses of global impact such as dengue virus. The infectious virus was purified from cell culture using polyethylene glycol (PEG) precipitation and density-gradient centrifugation. Thin amorphously shaped crystals of the lipid-enveloped virus were grown in quartz capillaries equilibrated by vapor diffusion. Crystal diffraction extended at best to a resolution of about 25 {angstrom} using synchrotron radiation. A preliminary analysis of the diffraction images indicated that the crystals had unit-cell parameters a {approx_equal} b {approx_equal} 480 {angstrom}, {gamma} = 120{sup o}, suggesting a tight hexagonal packing of one virus particle per unit cell.

  15. Vector competence of selected North American Culex and Coquillettidia mosquitoes for West Nile virus.

    Science.gov (United States)

    Sardelis, M R; Turell, M J; Dohm, D J; O'Guinn, M L

    2001-01-01

    To control West Nile virus (WNV), it is necessary to know which mosquitoes are able to transmit this virus. Therefore, we evaluated the WNV vector potential of several North American mosquito species. Culex restuans and Cx. salinarius, two species from which WNV was isolated in New York in 2000, were efficient laboratory vectors. Cx. quinquefasciatus and Cx. nigripalpus from Florida were competent but only moderately efficient vectors. Coquillettidia perturbans was an inefficient laboratory vector. As WNV extends its range, exposure of additional mosquito species may alter its epidemiology.

  16. Seroprevalence screening for the West Nile virus in Malaysia’s Orang Asli population

    OpenAIRE

    Marlina, Suria; Radzi, Siti Fatimah Muhd; Lani, Rafidah; Sieng, Khor Chee; Rahim, Nurul Farhana Abdul; Hassan, Habibi; Li-Yen, Chang; AbuBakar, Sazaly; Zandi, Keivan

    2014-01-01

    Background West Nile virus (WNV) infection is an emerging zoonotic disease caused by an RNA virus of the genus Flavivirus. WNV is preserved in the environment through cyclic transmission, with mosquitoes, particularly Culex species, serving as a vector, birds as an amplifying host and humans and other mammals as dead-end hosts. To date, no studies have been carried out to determine the prevalence of the WNV antibody in Malaysia. The aim of this study was to screen for the seroprevalence of th...

  17. West Nile Virus%西尼罗病毒

    Institute of Scientific and Technical Information of China (English)

    Lyle R. Petersen; Anthony A. Marfin; Duane J. Gubler

    2004-01-01

    西尼罗病毒(West Nile Virus,WNV)1999年首次侵入北美洲,在纽约市地区爆发脑膜脑炎导致7人死亡。在此之前,人们对它还不甚知晓。到2002年,人和兽医监测报告指出,在地理上它已向西扩展到太平洋沿岸。同年,WNV引起了北美史无前例的最大一次虫媒病毒脑炎爆发。

  18. A thiopurine drug inhibits West Nile virus production in cell culture, but not in mice.

    Directory of Open Access Journals (Sweden)

    Pei-Yin Lim

    Full Text Available Many viruses within the Flavivirus genus cause significant disease in humans; however, effective antivirals against these viruses are not currently available. We have previously shown that a thiopurine drug, 6-methylmercaptopurine riboside (6MMPr, inhibits replication of distantly related viruses within the Flaviviridae family in cell culture, including bovine viral diarrhea virus and hepatitis C virus replicon. Here we further examined the potential antiviral effect of 6MMPr on several diverse flaviviruses. In cell culture, 6MMPr inhibited virus production of yellow fever virus, dengue virus-2 (DENV-2 and West Nile virus (WNV in a dose-dependent manner, and DENV-2 was significantly more sensitive to 6MMPr treatment than WNV. We then explored the use of 6MMPr as an antiviral against WNV in an immunocompetent mouse model. Once a day treatment of mice with 0.5 mg 6MMPr was just below the toxic dose in our mouse model, and this dose was used in subsequent studies. Mice were treated with 6MMPr immediately after subcutaneous inoculation with WNV for eight consecutive days. Treatment with 6MMPr exacerbated weight loss in WNV-inoculated mice and did not significantly affect mortality. We hypothesized that 6MMPr has low bioavailability in the central nervous system (CNS and examined the effect of pre-treatment with 6MMPr on viral loads in the periphery and CNS. Pre-treatment with 6MMPr had no significant effect on viremia or viral titers in the periphery, but resulted in significantly higher viral loads in the brain, suggesting that the effect of 6MMPr is tissue-dependent. In conclusion, despite being a potent inhibitor of flaviviruses in cell culture, 6MMPr was not effective against West Nile disease in mice; however, further studies are warranted to reduce the toxicity and/or improve the bioavailability of this potential antiviral drug.

  19. Proteomic Profiling and Neurodegeneration in West-Nile-Virus-Infected Neurons

    Directory of Open Access Journals (Sweden)

    V. Dhingra

    2005-01-01

    Full Text Available West Nile virus, a mosquito-borne flavivirus, is a human, equine, and avian pathogen. High-resolution two-dimensional differential-gel electrophoresis (2D-DIGE was used to characterize protein expression in primary rat neurons and to examine the proteomic profiling to understand the pathogenesis of West-Nile-associated meningoencephalitis. Three pH ranges, 3–10, 4–7, and 5–6, were used to analyze the protein spots. The proteins are labeled with fluorescent dyes Cy3 and Cy5 before being separated on the basis of charge and size respectively on a two-dimensional platform. About 55 proteins showed altered expression levels. These were then subsequently digested and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS analysis using peptide mass fingerprinting and database searching. These cellular proteins could represent distinct roles during infection related to apoptosis. Our findings show that two-dimensional differential gel electrophoresis combined with mass spectrometry is a powerful approach that permits the identification of proteins whose expression was altered due to West Nile virus infection.

  20. Predictive modeling of West Nile virus transmission risk in the Mediterranean Basin: how far from landing?

    Science.gov (United States)

    Chevalier, Véronique; Tran, Annelise; Durand, Benoit

    2014-01-01

    The impact on human and horse health of West Nile fever (WNF) recently and dramatically increased in Europe and neighboring countries. Involving several mosquito and wild bird species, WNF epidemiology is complex. Despite the implementation of surveillance systems in several countries of concern, and due to a lack of knowledge, outbreak occurrence remains unpredictable. Statistical models may help identifying transmission risk factors. When spatialized, they provide tools to identify areas that are suitable for West Nile virus transmission. Mathematical models may be used to improve our understanding of epidemiological process involved, to evaluate the impact of environmental changes or test the efficiency of control measures. We propose a systematic literature review of publications aiming at modeling the processes involved in WNF transmission in the Mediterranean Basin. The relevance of the corresponding models as predictive tools for risk mapping, early warning and for the design of surveillance systems in a changing environment is analyzed. PMID:24362544

  1. Predictive Modeling of West Nile Virus Transmission Risk in the Mediterranean Basin: How Far from Landing?

    Directory of Open Access Journals (Sweden)

    Véronique Chevalier

    2013-12-01

    Full Text Available The impact on human and horse health of West Nile fever (WNF recently and dramatically increased in Europe and neighboring countries. Involving several mosquito and wild bird species, WNF epidemiology is complex. Despite the implementation of surveillance systems in several countries of concern, and due to a lack of knowledge, outbreak occurrence remains unpredictable. Statistical models may help identifying transmission risk factors. When spatialized, they provide tools to identify areas that are suitable for West Nile virus transmission. Mathematical models may be used to improve our understanding of epidemiological process involved, to evaluate the impact of environmental changes or test the efficiency of control measures. We propose a systematic literature review of publications aiming at modeling the processes involved in WNF transmission in the Mediterranean Basin. The relevance of the corresponding models as predictive tools for risk mapping, early warning and for the design of surveillance systems in a changing environment is analyzed.

  2. West Nile virus experimental evolution in vivo and the trade-off hypothesis.

    Directory of Open Access Journals (Sweden)

    Eleanor R Deardorff

    2011-11-01

    Full Text Available In nature, arthropod-borne viruses (arboviruses perpetuate through alternating replication in vertebrate and invertebrate hosts. The trade-off hypothesis proposes that these viruses maintain adequate replicative fitness in two disparate hosts in exchange for superior fitness in one host. Releasing the virus from the constraints of a two-host cycle should thus facilitate adaptation to a single host. This theory has been addressed in a variety of systems, but remains poorly understood. We sought to determine the fitness implications of alternating host replication for West Nile virus (WNV using an in vivo model system. Previously, WNV was serially or alternately passed 20 times in vivo in chicks or mosquitoes and resulting viruses were characterized genetically. In this study, these test viruses were competed in vivo in fitness assays against an unpassed marked reference virus. Fitness was assayed in chicks and in two important WNV vectors, Culex pipiens and Culex quinquefasciatus. Chick-specialized virus displayed clear fitness gains in chicks and in Cx. pipiens but not in Cx. quinquefasciatus. Cx. pipiens-specialized virus experienced reduced fitness in chicks and little change in either mosquito species. These data suggest that when fitness is measured in birds the trade-off hypothesis is supported; but in mosquitoes it is not. Overall, these results suggest that WNV evolution is driven by alternate cycles of genetic expansion in mosquitoes, where purifying selection is weak and genetic diversity generated, and restriction in birds, where purifying selection is strong.

  3. Vector competence of North American mosquitoes (Diptera: Culicidae) for West Nile virus.

    Science.gov (United States)

    Turell, M J; O'Guinn, M L; Dohm, D J; Jones, J W

    2001-03-01

    We evaluated the potential for several North American mosquito species to transmit the newly introduced West Nile (WN) virus. Mosquitoes collected in the New York City metropolitan area during the recent WN virus outbreak, at the Assateague Island Wildlife Refuge, VA, or from established colonies were allowed to feed on chickens infected with WN virus isolated from a crow that died during the 1999 outbreak. These mosquitoes were tested approximately 2 wk later to determine infection, dissemination, and transmission rates. Aedes albopictus (Skuse), Aedes atropalpus (Coquillett), and Aedes japonicus (Theobald) were highly susceptible to infection, and nearly all individuals with a disseminated infection transmitted virus by bite. Culex pipiens L. and Aedes sollicitans (Walker) were moderately susceptible. In contrast, Aedes vexans (Meigen), Aedes aegypti (L.), and Aedes taeniorhynchus (Wiedemann) were relatively refractory to infection, but individual mosquitoes inoculated with WN virus did transmit virus by bite. Infected female Cx. pipiens transmitted WN virus to one of 1,618 F1 progeny, indicating the potential for vertical transmission of this virus. In addition to laboratory vector competence, host-feeding preferences, relative abundance, and season of activity also determine the role that these species could play in transmitting WN virus.

  4. Using high titer West Nile intravenous immunoglobulin from selected Israeli donors for treatment of West Nile virus infection

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    Gottreich Ahuva

    2009-02-01

    Full Text Available Abstract Background West Nile Virus (WNV is endemic in Israel and a significant level of antibodies is present in the population due to natural exposure. Anecdotal cases suggested that the presence of anti-WNV antibodies in intravenous immunoglobulin (IVIG from Israeli donors (IVIG-IL assisted the recovery of patients with severe WNV infection. Methods To enhance the therapeutic efficacy of IVIG-IL against WNV infection, OMRIX Biopharmaceuticals, Israel, have developed a strategy for selection of plasma units from a 10% fraction of Israeli blood donors with anti-WNV antibodies. Positive units were processed into pharmaceutical grade WNV IVIG (WNIG. Following inoculation with WNV, mice received i.p. injections of different doses (0.01–8 mg/mouse of IVIG-IL or WNIG, according to the specific experimental protocol. Results WNIG was about 10 times more potent (per gr of IgG than was regular IVIG-IL when tested by ELISA and neutralization assays. In a mouse lethal WNV infection model, prophylactic treatment with WNIG was at least 5–10-fold more potent as compared to treatment with IVIG-IL. Treatment with WNIG during active encephalitis, three or four days following WNV infection, had a significant protective effect. WNIG was also very effective in protecting immunosuppressed mice. Indeed, treatment of dexamethasone-immunosuppressed mice with 0.2 or 1.0 mg WNIG 4 h after virus infection, led to 100% survival. Conclusion IVIG produced from selected plasma donated in WNV endemic regions can be used to produce WNV IVIG with superior activity for therapeutic and prophylactic measures.

  5. Pathogenicity of West Nile virus and response to vaccination in sandhill cranes (Grus canadensis) using a killed vaccine.

    Science.gov (United States)

    Olsen, G.H.; Miller, K.J.; Docherty, D.E.; Bochsler, V.S.; Sileo, L.

    2009-01-01

    West Nile virus was introduced into the United States in the vicinity of New York, New York, USA in 1999. The virus has since killed large numbers of birds nationwide, especially, but not limited to, crows (Corvus brachyrhinchos). One sandhill crane (Grus canadensis) at the Bridgeport Zoo (Bridgeport, Connecticut, USA) reportedly died from West Nile virus, so sandhill cranes and endangered whooping cranes (Grus americana), both in the wild and in captive breeding colonies at United States Geological Service (USGS) Patuxent Wildlife Research Center (Laurel, Maryland, USA) were considered at risk. A killed vaccine in sandhill cranes was evaluated by vaccinating and then challenging these cranes with live West Nile virus. No sandhill cranes inoculated with the killed vaccine developed significant titers when compared with unvaccinated controls. No sandhill cranes inoculated with the vaccine and challenged with the virus died from West Nile virus infection. In addition, no unvaccinated challenged sandhill cranes died. However, 2 days postchallenge, vaccinated cranes had significantly less viremia (P cell aggregates in both the brain and brain stem areas, and this was not observed in vaccinated challenged cranes or in vaccinated unchallenged cranes.

  6. Large Human Outbreak of West Nile Virus Infection in North-Eastern Italy in 2012

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    Luisa Barzon

    2013-11-01

    Full Text Available Human cases of West Nile virus (WNV disease have been reported in Italy since 2008. So far, most cases have been identified in north-eastern Italy, where, in 2012, the largest outbreak of WNV infection ever recorded in Italy occurred. Most cases of the 2012 outbreak were identified in the Veneto region, where a special surveillance plan for West Nile fever was in place. In this outbreak, 25 cases of West Nile neuroinvasive disease and 17 cases of fever were confirmed. In addition, 14 WNV RNA-positive blood donors were identified by screening of blood and organ donations and two cases of asymptomatic infection were diagnosed by active surveillance of subjects at risk of WNV exposure. Two cases of death due to WNND were reported. Molecular testing demonstrated the presence of WNV lineage 1 in all WNV RNA-positive patients and, in 15 cases, infection by the novel Livenza strain was ascertained. Surveillance in other Italian regions notified one case of neuroinvasive disease in the south of Italy and two cases in Sardinia. Integrated surveillance for WNV infection remains a public health priority in Italy and vector control activities have been strengthened in areas of WNV circulation.

  7. Specific interaction of capsid protein and importin-{alpha}/{beta} influences West Nile virus production

    Energy Technology Data Exchange (ETDEWEB)

    Bhuvanakantham, Raghavan; Chong, Mun-Keat [Flavivirology Laboratory, Department of Microbiology, 5 Science Drive 2, National University of Singapore, Singapore 117597 (Singapore); Ng, Mah-Lee, E-mail: micngml@nus.edu.sg [Flavivirology Laboratory, Department of Microbiology, 5 Science Drive 2, National University of Singapore, Singapore 117597 (Singapore)

    2009-11-06

    West Nile virus (WNV) capsid (C) protein has been shown to enter the nucleus of infected cells. However, the mechanism by which C protein enters the nucleus is unknown. In this study, we have unveiled for the first time that nuclear transport of WNV and Dengue virus C protein is mediated by their direct association with importin-{alpha}. This interplay is mediated by the consensus sequences of bipartite nuclear localization signal located between amino acid residues 85-101 together with amino acid residues 42 and 43 of C protein. Elucidation of biological significance of importin-{alpha}/C protein interaction demonstrated that the binding efficiency of this association influenced the nuclear entry of C protein and virus production. Collectively, this study illustrated the molecular mechanism by which the C protein of arthropod-borne flavivirus enters the nucleus and showed the importance of importin-{alpha}/C protein interaction in the context of flavivirus life-cycle.

  8. Characterization of West Nile viruses isolated form captive American flamingoes (Phoenicopterus ruber) in Medellin, Colombia.

    Science.gov (United States)

    Osorio, Jorge E.; Ciuoderis, Karl A.; Lopera, Juan G.; Piedrahita, Leidy D.; Murphy, Darby; LeVasseur, James; Carrillo, Lina; Ocampo, Martha C.; Hofmeister, Erik

    2012-01-01

    Serum samples from a total of 71 healthy captive birds belonging to 18 species were collected in July of 2008 in Medellin (Colombia) and tested for flaviviruses. Eighteen of 29 samples from American Flamingoes (Phoenicopterus ruber) were positive for West Nile virus (WNV) by reverse transcription-polymerase chain reaction. Selected positive samples were serially passaged and WNV was confirmed by immunofluorescence. Two isolates (524/08, 9835/08) were characterized in vitro and in vivo. Sequence analysis revealed WNV with 16 nucleotide substitutions resulting in six amino acid changes when compared with the NY99 strain. Colombian (COL) viruses were more closely related to Louisiana isolates from 2001. When compared with attenuated strains isolated from Texas, COL isolates differed in their plaque size and temperature sensitivity phenotype. The COL viruses were pathogenic in embryonated chicken eggs and Balb/c mice.

  9. Pathology of fatal lineage 1 and 2 West Nile virus infections in horses in South Africa

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    June H. Williams

    2014-02-01

    Full Text Available Since 2007, West Nile virus (WNV has been reported in South African horses, causing severe neurological signs. All cases were of lineage 2, except for one case that clustered with lineage 1 viruses. In the present study, gross and microscopic lesions of six South African lineage 2-infected horses and the one lineage 1 case are described. Diagnoses were confirmed by real-time reverse-transcriptase polymerase chain reaction (RT-PCR of central nervous system (CNS tissue and one by RT-PCR of a brain virus isolate. The CNS of all cases was negative by RT-PCR or immunohistochemistry (IHC for African horse sickness (AHS, equine encephalosis virus, equine herpes viruses 1 and 4, other zoonotic flaviviruses, alphaviruses, and shunivirus, and either by immunofluorescence or IHC for rabies. Gross visceral lesions were nonspecific but often mimicked those of AHS. The CNS histopathology of WNV lineage 2 cases resembled the nonsuppurative polioencephalomyelitis reported in the Northern Hemisphere lineage 1 and recent Hungarian lineage 2 cases. Occasional meningitis, focal spinal ventral horn poliomalacia, dorsal and lateral horn poliomyelitis, leucomyelitis, asymmetrical ventral motor spinal neuritis and frequent olfactory region involvement were also seen. Lineage 2 cases displayed marked variations in CNS lesion severity, type and distribution, and suggested various viral entry routes into the CNS, based on findings in experimental mice and hamsters. Lineage 1 lesions were comparable to the milder lineage 2 cases. West Nile virus IHC on CNS sections with marked lesions from all cases elicited only two antigen-positive cells in the olfactory cortex of one case. The presence in the CNS of T-lymphocytes, B-lymphocytes, plasma cells and macrophage-monocytes was confirmed by cluster of differentiation (CD 3, CD20, multiple myeloma oncogene 1 (MUM1 and macrophage (MAC 387 IHC.

  10. Experimental West Nile virus infection in Eastern Screech Owls (Megascops asio)

    Science.gov (United States)

    Nemeth, N.M.; Hahn, D.C.; Gould, D.H.; Bowen, R.A.

    2006-01-01

    Eastern Screech Owls (EASOs) were experimentally infected with the pathogenic New York 1999 strain of West Nile virus (WNV) by subcutaneous injection or per os. Two of nine subcutaneously inoculated birds died or were euthanatized on 8 or 9 days postinfection (DPI) after myocardial and skeletal muscle necrosis and mild encephalitis and nephritis, whereas some of the clinically healthy birds that were sacrificed on 14 DPI had myocardial arteritis and renal phlebitis. WNV is a significant pathogen of EASOs, causing pathologic lesions with varying clinical outcomes.

  11. West Nile virus reemergence in Romania: a serologic survey in host species.

    Science.gov (United States)

    Ludu Oslobanu, Elena Luanda; Mihu-Pintilie, Alin; Anită, Dragos; Anita, Adriana; Lecollinet, Sylvie; Savuta, Gheorghe

    2014-05-01

    The presence of West Nile virus (WNV) in humans has been known in Romania since the 1950s; the 1996 epidemics emphasized the reemergence potential of WNV in Romania. Serological surveys made on susceptible species, known as good sentinels or reservoir hosts, e.g., horses, wild and domestic birds were undertaken from 2006-2011. Our results corroborated incidence data in human patients and other recent seroprevalence studies in animals, and should partially clarify the emergence of WNV in the eastern rural territories of Romania. It also highlighted risk zones for endemic WNV infection in Romania. PMID:24745699

  12. Antibodies to West Nile virus in wild and farmed crocodiles in southeastern Mexico.

    Science.gov (United States)

    Machain-Williams, Carlos; Padilla-Paz, Sergio E; Weber, Manuel; Cetina-Trejo, Rosa; Juarez-Ordaz, José Alfredo; Loroño-Pino, María Alba; Ulloa, Armando; Wang, Chong; Garcia-Rejon, Julián; Blitvich, Bradley J

    2013-07-01

    Surveillance for evidence of West Nile virus (WNV) infection in Morelet's crocodiles (Crocodylus moreletii) was conducted in Campeche State, Mexico, in 2007. Sera from 62 crocodiles (32 free-ranging and 30 captive) were assayed for antibodies to WNV by epitope-blocking enzyme-linked immunosorbent assay. Antibodies to WNV were detected in 13 (41%) wild and nine (30%) captive crocodiles, and the overall antibody prevalence was 35%. Although evidence of WNV infection in captive crocodiles has been reported in Mexico, we provide the first evidence of WNV exposure in wild crocodiles in Mexico. PMID:23778623

  13. Detection of West Nile virus genome and specific antibodies in Iranian encephalitis patients

    DEFF Research Database (Denmark)

    Chinikar, S; Javadi, A; Ataei, B;

    2012-01-01

    West Nile virus (WNV) is a mosquito-borne flavivirus which circulates in birds, horses and humans. An estimated 80% of WNV infections are asymptomatic. Fewer than 1% of infected persons develop neuroinvasive disease, which typically presents as encephalitis, meningitis, or acute flaccid paralysis...... with evidence of meningitis being excluded. Patients' CSF and serum were diagnosed by serological and molecular assays. A total of 632 patients with fever and loss of consciousness were tested by CSF analyses. Samples of the remaining patients (39·4%) were referred for WNV investigation. Three (1...

  14. West Nile virus lineage 2 infection in a blood donor from Vienna, Austria, August 2014.

    Science.gov (United States)

    Jungbauer, C; Hourfar, M K; Stiasny, K; Aberle, S W; Cadar, D; Schmidt-Chanasit, J; Mayr, W R

    2015-03-01

    Eastern Austria is neighbouring regions with ongoing West Nile virus (WNV) transmissions. Three human WNV infections had been diagnosed during the past decade in Austria. The Austrian Red Cross Blood Service (ARC-BS) started a first voluntary screening for WNV in blood donors from Eastern Austria by Nucleic Acid Testing (NAT) in June 2014. This is also the most extensive WNV surveillance programme in humans in Austria so far. In August 2014, one autochthonous WNV infection was detected in a blood donor from Vienna. By now, one in 67,800 whole blood donations was found to be positive for WNV RNA.

  15. Development and Characterization of West Nile Virus Replicon Expressing Secreted Gaussia Luciferase

    Institute of Scientific and Technical Information of China (English)

    Chao Shan; Xiaodan Li; Chenglin Deng; Baodi Shang; Linlin Xu; Hanqing Ye; Zhiming Yuan

    2013-01-01

    We developed a Gaussia luciferase (Gluc) reporter replicon of West Nile virus (WNV) and used it to quantify viral translation and RNA replication.The advantage of the Gluc replicon is that Gaussia luciferase is secreted into the culture medium from cells transfected with Gluc replicon RNA,and the medium can be assayed directly for luciferase activity.Using a known Flavivirus inhibitor (NITD008),we demonstrated that the Gluc-WNV replicon could be used for antiviral screening.The Gluc-WNV-Rep will be useful for research in antiviral drug development programs,as well as for studying viral replication and pathogenesis of WNV.

  16. Association between high expression macrophage migration inhibitory factor (MIF) alleles and West Nile virus encephalitis.

    Science.gov (United States)

    Das, Rituparna; Loughran, Kerry; Murchison, Charles; Qian, Feng; Leng, Lin; Song, Yan; Montgomery, Ruth R; Loeb, Mark; Bucala, Richard

    2016-02-01

    Infection with mosquito-borne West Nile virus (WNV) is usually asymptomatic but can lead to severe WNV encephalitis. The innate cytokine, macrophage migration inhibitory factor (MIF), is elevated in patients with WNV encephalitis and promotes viral neuroinvasion and mortality in animal models. In a case-control study, we examined functional polymorphisms in the MIF locus in a cohort of 454 North American patients with neuroinvasive WNV disease and found patients homozygous for high-expression MIF alleles to be >20-fold (p=0.008) more likely to have WNV encephalitis. These data indicate that MIF is an important determinant of severity of WNV neuropathogenesis and may be a therapeutic target.

  17. West Nile Virus and Other Nationally Notifiable Arboviral Diseases - United States, 2014.

    Science.gov (United States)

    Lindsey, Nicole P; Lehman, Jennifer A; Staples, J Erin; Fischer, Marc

    2015-09-01

    Arthropod-borne viruses (arboviruses) are transmitted to humans primarily through the bites of infected mosquitoes and ticks. West Nile virus (WNV) is the leading cause of domestically acquired arboviral disease in the United States (1). However, several other arboviruses also cause sporadic cases and seasonal outbreaks. This report summarizes surveillance data reported to CDC in 2014 for WNV and other nationally notifiable arboviruses, excluding dengue. Forty-two states and the District of Columbia (DC) reported 2,205 cases of WNV disease. Of these, 1,347 (61%) were classified as WNV neuroinvasive disease (e.g., meningitis, encephalitis, or acute flaccid paralysis), for a national incidence of 0.42 cases per 100,000 population. After WNV, the next most commonly reported cause of arboviral disease was La Crosse virus (80 cases), followed by Jamestown Canyon virus (11), St. Louis encephalitis virus (10), Powassan virus (8), and Eastern equine encephalitis virus (8). WNV and other arboviruses cause serious illness in substantial numbers of persons each year. Maintaining surveillance programs is important to help direct prevention activities. PMID:26334477

  18. Transmission of West Nile virus by Culex quinquefasciatus say infected with Culex Flavivirus Izabal.

    Directory of Open Access Journals (Sweden)

    Rebekah J Kent

    Full Text Available BACKGROUND: The natural history and potential impact of mosquito-specific flaviviruses on the transmission efficiency of West Nile virus (WNV is unknown. The objective of this study was to determine whether or not prior infection with Culex flavivirus (CxFV Izabal altered the vector competence of Cx. quinquefasciatus Say for transmission of a co-circulating strain of West Nile virus (WNV from Guatemala. METHODS AND FINDINGS: CxFV-negative Culex quinquefasciatus and those infected with CxFV Izabal by intrathoracic inoculation were administered WNV-infectious blood meals. Infection, dissemination, and transmission of WNV were measured by plaque titration on Vero cells of individual mosquito bodies, legs, or saliva, respectively, two weeks following WNV exposure. Additional groups of Cx. quinquefasciatus were intrathoracically inoculated with WNV alone or WNV+CxFV Izabal simultaneously, and saliva collected nine days post inoculation. Growth of WNV in Aedes albopictus C6/36 cells or Cx. quinquefasciatus was not inhibited by prior infection with CxFV Izabal. There was no significant difference in the vector competence of Cx. quinquefasciatus for WNV between mosquitoes uninfected or infected with CxFV Izabal across multiple WNV blood meal titers and two colonies of Cx. quinquefasciatus (p>0.05. However, significantly more Cx. quinquefasciatus from Honduras that were co-inoculated simultaneously with both viruses transmitted WNV than those inoculated with WNV alone (p = 0.0014. Co-inoculated mosquitoes that transmitted WNV also contained CxFV in their saliva, whereas mosquitoes inoculated with CxFV alone did not contain virus in their saliva. CONCLUSIONS: In the sequential infection experiments, prior infection with CxFV Izabal had no significant impact on WNV replication, infection, dissemination, or transmission by Cx. quinquefasciatus, however WNV transmission was enhanced in the Honduras colony when mosquitoes were inoculated simultaneously with

  19. Noncoding Subgenomic Flavivirus RNA: Multiple Functions in West Nile Virus Pathogenesis and Modulation of Host Responses

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    Justin A. Roby

    2014-01-01

    Full Text Available Flaviviruses are a large group of positive strand RNA viruses transmitted by arthropods that include many human pathogens such as West Nile virus (WNV, Japanese encephalitis virus (JEV, yellow fever virus, dengue virus, and tick-borne encephalitis virus. All members in this genus tested so far are shown to produce a unique subgenomic flavivirus RNA (sfRNA derived from the 3' untranslated region (UTR. sfRNA is a product of incomplete degradation of genomic RNA by the cell 5'–3' exoribonuclease XRN1 which stalls at highly ordered secondary RNA structures at the beginning of the 3'UTR. Generation of sfRNA results in inhibition of XRN1 activity leading to an increase in stability of many cellular mRNAs. Mutant WNV deficient in sfRNA generation was highly attenuated displaying a marked decrease in cytopathicity in cells and pathogenicity in mice. sfRNA has also been shown to inhibit the antiviral activity of IFN-α/β by yet unknown mechanism and of the RNAi pathway by likely serving as a decoy substrate for Dicer. Thus, sfRNA is involved in modulating multiple cellular pathways to facilitate viral pathogenicity; however the overlying mechanism linking all these multiple functions of sfRNA remains to be elucidated.

  20. Impact of Climate and Environmental Factors on West Nile Virus Circulation in Iran

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    Farzaneh Ahmadnejad

    2016-01-01

    Full Text Available Background: Geographic distribution of West Nile virus (WNV is heterogeneous in Iran by a high circulation in the southern-western areas. The objective of our study was to determine environmental and climatic factors associ­ated with the risk of WNV equine seropositivity in Iran.Methods: Serological data were obtained from a serosurvey conducted in equine population in 260 districts in Iran. The climate and environmental parameters included in the models were distance to the nearest wetland area, type of stable, Normalized Difference Vegetation Index (NDVI, annual mean temperature, humidity and precipitation.Results: The important risk factors included annual mean temperature, distance to wetlands, local and seasonal NDVI differences. The effect of local NDVI differences in spring was particularly notable. This was a normalized difference of average NDVI between two areas: a 5 km radius area centered on the stable and the 5–10 km sur­rounding area.Conclusion: The model indicated that local NDVI’s contrast during spring is a major risk factor of the transmission of West-Nile virus in Iran. This so-called oasis effect consistent with the seasonal production of vegetation in spring, and is associated to the attractiveness of the local NDVI environment for WNV vectors and hosts.  

  1. Fever of Unknown Origin in a Patient with Confirmed West Nile Virus Meningoencephalitis

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    Alexander Sabre

    2014-01-01

    Full Text Available West Nile Virus (WNV, an RNA arbovirus and member of the Japanese encephalitis virus antigenic complex, causes a wide range of clinical symptoms, from asymptomatic to encephalitis and meningitis. Nearly all human infections of WNV are due to mosquito bites with birds being the primary amplifying hosts. Advanced age is the most important risk factor for neurological disease leading most often to poor prognosis in those afflicted. We report a case of WNV meningoencephalitis in a 93-year-old Caucasian male who presented with fever of unknown origin (FUO and nuchal rigidity that rapidly decompensated within 24 h to a persistent altered mental state during inpatient stay. The patient’s ELISA antibody titers confirmed pathogenesis of disease by WNV; he given supportive measures and advanced to an excellent recovery. In regard to the approach of FUO, it is important to remain impartial yet insightful to all elements when determining pathogenesis in atypical presentation.

  2. Flaviviruses, an expanding threat in public health: focus on dengue, West Nile, and Japanese encephalitis virus.

    Science.gov (United States)

    Daep, Carlo Amorin; Muñoz-Jordán, Jorge L; Eugenin, Eliseo Alberto

    2014-12-01

    The flaviviruses dengue, West Nile, and Japanese encephalitis represent three major mosquito-borne viruses worldwide. These pathogens impact the lives of millions of individuals and potentially could affect non-endemic areas already colonized by mosquito vectors. Unintentional transport of infected vectors (Aedes and Culex spp.), traveling within endemic areas, rapid adaptation of the insects into new geographic locations, climate change, and lack of medical surveillance have greatly contributed to the increase in flaviviral infections worldwide. The mechanisms by which flaviviruses alter the immune and the central nervous system have only recently been examined despite the alarming number of infections, related deaths, and increasing global distribution. In this review, we will discuss the expansion of the geographic areas affected by flaviviruses, the potential threats to previously unaffected countries, the mechanisms of pathogenesis, and the potential therapeutic interventions to limit the devastating consequences of these viruses. PMID:25287260

  3. Virulence and Evolution of West Nile Virus, Australia, 1960-2012.

    Science.gov (United States)

    Prow, Natalie A; Edmonds, Judith H; Williams, David T; Setoh, Yin X; Bielefeldt-Ohmann, Helle; Suen, Willy W; Hobson-Peters, Jody; van den Hurk, Andrew F; Pyke, Alyssa T; Hall-Mendelin, Sonja; Northill, Judith A; Johansen, Cheryl A; Warrilow, David; Wang, Jianning; Kirkland, Peter D; Doggett, Stephen; Andrade, Christy C; Brault, Aaron C; Khromykh, Alexander A; Hall, Roy A

    2016-08-01

    Worldwide, West Nile virus (WNV) causes encephalitis in humans, horses, and birds. The Kunjin strain of WNV (WNVKUN) is endemic to northern Australia, but infections are usually asymptomatic. In 2011, an unprecedented outbreak of equine encephalitis occurred in southeastern Australia; most of the ≈900 reported cases were attributed to a newly emerged WNVKUN strain. To investigate the origins of this virus, we performed genetic analysis and in vitro and in vivo studies of 13 WNVKUN isolates collected from different regions of Australia during 1960-2012. Although no disease was recorded for 1984, 2000, or 2012, isolates collected during those years (from Victoria, Queensland, and New South Wales, respectively) exhibited levels of virulence in mice similar to that of the 2011 outbreak strain. Thus, virulent strains of WNVKUN have circulated in Australia for >30 years, and the first extensive outbreak of equine disease in Australia probably resulted from a combination of specific ecologic and epidemiologic conditions. PMID:27433830

  4. Vector competence of Culex tarsalis from Orange County, California, for West Nile virus.

    Science.gov (United States)

    Turell, Michael J; O'Guinn, Monica L; Dohm, David J; Webb, James P; Sardelis, Michael R

    2002-01-01

    To evaluate the vector competence of Culex tarsalis Coquillett for West Nile virus (WN), females reared from larvae collected in Huntington Beach, Orange County, CA, were fed on 2-3-day-old chickens previously inoculated with a New York strain (Crow 397-99) of WN. The Cx. tarsalis mosquitoes were efficient laboratory vectors of WN, with estimated transmission rates of 81% and 91% for mosquitoes that ingested 10(6.5) or 10(7.3) plaque-forming units of WN/mL of blood, respectively. Based on efficiency of viral transmission and the role of this species in the transmission of the closely related St. Louis encephalitis virus, Cx. tarsalis should be considered a potentially important vector of WN in the western United States.

  5. Spatially explicit West Nile virus risk modeling in Santa Clara County, California.

    Science.gov (United States)

    Konrad, Sarah K; Miller, Scott N; Reeves, Will K; Tietze, Noor S

    2009-06-01

    A geographic information system model designed to identify regions at risk for West Nile virus (WNV) transmission was calibrated and tested with data collected in Santa Clara County, California. American Crows that died from WNV infection in 2005 provided spatial and temporal ground truth. When the model was run with parameters based on Culex tarsalis infected with the NY99 genotype of the virus, it underestimated WNV occurrence in Santa Clara Co. The parameters were calibrated to fit the field data by reducing the number of degree-days necessary to reach the mosquito's extrinsic incubation period from 109 to 76. The calibration raised model efficiency from 61% to 92% accuracy, and the model performed well the following year in Santa Clara Co.

  6. Fever of Unknown Origin in a Patient with Confirmed West Nile Virus Meningoencephalitis

    Science.gov (United States)

    Sabre, Alexander; Farricielli, Laurie

    2014-01-01

    West Nile Virus (WNV), an RNA arbovirus and member of the Japanese encephalitis virus antigenic complex, causes a wide range of clinical symptoms, from asymptomatic to encephalitis and meningitis. Nearly all human infections of WNV are due to mosquito bites with birds being the primary amplifying hosts. Advanced age is the most important risk factor for neurological disease leading most often to poor prognosis in those afflicted. We report a case of WNV meningoencephalitis in a 93-year-old Caucasian male who presented with fever of unknown origin (FUO) and nuchal rigidity that rapidly decompensated within 24 h to a persistent altered mental state during inpatient stay. The patient's ELISA antibody titers confirmed pathogenesis of disease by WNV; he given supportive measures and advanced to an excellent recovery. In regard to the approach of FUO, it is important to remain impartial yet insightful to all elements when determining pathogenesis in atypical presentation. PMID:25580318

  7. Risk factors for West Nile virus Infection and Disease in Populations and Individuals

    Science.gov (United States)

    Montgomery, Ruth R.; Murray, Kristy O.

    2016-01-01

    Summary West Nile virus (WNV) is a mosquito-borne enveloped positive-strand RNA virus that emerged in North America in 1999 in New York City. Over the past 15 years, WNV has become established throughout the USA and has spread into Canada, Mexico and the Caribbean. CDC reports indicate >41,000 clinical cases, including more than 1,700 fatalities. An estimated 3 million people in the USA may have been infected to date. Infection with WNV is dependent on many factors including climate, mosquito habitats and immunologically-naïve bird populations. In addition, variations within individuals contribute to the risk of severe disease, in particular, advanced age, hypertension, immunosuppression and critical elements of the immune response. Recent advances in technology now allow detailed analysis of complex immune interactions relevant to disease susceptibility. PMID:25637260

  8. On the potential roles of ticks and migrating birds in the ecology of West Nile virus

    Directory of Open Access Journals (Sweden)

    Karl Hagman

    2014-01-01

    Full Text Available Background: Mosquitoes are the primary vectors of West Nile virus (WNV. Ticks have, however, been suggested to be potential reservoirs of WNV. To investigate their role in the spread of the virus, ticks, which had been collected from birds migrating northward from Africa to Europe, were analyzed for the potential presence of WNV RNA. Methods: On the Mediterranean islands of Capri and Antikythira, a total of 14,824 birds were captured and investigated from which 747 ticks were collected. Results and conclusions: Most of the identified ticks (93% were nymphs and larvae of Hyalomma marginatum sensu lato (s.l., most of which were or appear to be Hyalomma rufipes. Of these ticks, 729 were individually screened for WNV RNA. None of the ticks was found to be WNV positive. Thus, there was no evidence that H. marginatum s.l. ticks play a role in the spread of WNV from Africa to Europe.

  9. Genotype-specific variation in West Nile virus dispersal in California.

    Science.gov (United States)

    Duggal, Nisha K; Reisen, William K; Fang, Ying; Newman, Ruchi M; Yang, Xiao; Ebel, Gregory D; Brault, Aaron C

    2015-11-01

    West Nile virus (WNV) is an arbovirus that was first reported in North America in New York in 1999 and, by 2003, had spread more than 4000 km to California. However, variation in viral genetics associated with spread is not well understood. Herein, we report sequences for more than 100 WNV isolates made from mosquito pools that were collected from 2003 to 2011 as part of routine surveillance by the California Mosquito-borne Virus Surveillance System. We performed phylogeographic analyses and demonstrated that 5 independent introductions of WNV (1 WN02 genotype strain and 4 SW03 genotype strains) occurred in California. The SW03 genotype of WNV was constrained to the southwestern U.S. and had a more rapid rate of spread. In addition, geographic constraint of WNV strains within a single region for up to 6 years suggest viral maintenance has been driven by resident, rather than migratory, birds and overwintering in mosquitoes.

  10. West Nile virus and hemoparasites in captive snowy owls (Bubo scandiacus) — management strategies to optimize survival

    OpenAIRE

    Harasym, Carol A.

    2008-01-01

    In August 2005, 2 members of a group of 6 captive snowy owls (Bubo scandiacus) in central Saskatchewan died of West Nile virus infection. One of these owls and 3 of the remaining owls had significant numbers of circulating hemoparasites. Management strategies are suggested to reduce morbidity and mortality.

  11. Winter Activity and Aboveground Hybridization Between the Two Biotypes of the West Nile Virus Vector Culex pipiens

    NARCIS (Netherlands)

    Vogels, C.B.F.; Peppel, van de L.J.J.; Vliet, van A.J.H.; Westenberg, M.; Ibanez-Justicia, A.; Stroo, A.; Buijs, J.A.; Visser, T.M.; Koenraadt, C.J.M.

    2015-01-01

    Culex (Cx.) pipiens mosquitoes are important vectors of West Nile virus (WNV). In Europe, the species Cx. pipiens consists of two biotypes, pipiens and molestus, which are morphologically identical, but differ in behavior. Typical behavior of the molestus biotype is the ability to remain active duri

  12. The capsid-coding region hairpin element (cHP) is a critical determinant of dengue virus and West Nile virus RNA synthesis

    OpenAIRE

    Clyde, Karen; Barrera, Julio; Harris, Eva

    2008-01-01

    Dengue virus (DENV) and West Nile virus (WNV) are members of the Flavivirus genus of positive-strand RNA viruses. RNA sequences and structures, primarily in the untranslated regions, have been shown to modulate flaviviral gene expression and genome replication. Previously, we demonstrated that a structure in the DENV coding region (cHP) enhances translation start codon selection and is required for viral replication. Here we further characterize the role of the cHP in the DENV life cycle. We ...

  13. Fusion loop peptide of the West Nile virus envelope protein is essential for pathogenesis and recognized by a therapeutic cross-reactive human monoclonal antibody

    OpenAIRE

    Sultana, Hameeda; Foellmer, Harald G.; Neelakanta, Girish; Oliphant, Theodore; Engle, Michael; Ledizet, Michel; Krishnan, Manoj; Bonafe, Nathalie; Anthony, Karen G.; Marasco, Wayne A.; Kaplan, Paul; Montgomery, Ruth R.; Diamond, Michael S.; Koski, Raymond A.; Fikrig, Erol

    2009-01-01

    West Nile virus is an emerging pathogen that can cause fatal neurological disease. A recombinant human monoclonal antibody, mAb11, has been described as a candidate for the prevention and treatment of West Nile disease. Using a yeast surface display epitope mapping assay and neutralization escape mutant, we show that mAb11 recognizes the fusion loop, at the distal end of domain II of the West Nile virus envelope protein. Antibody mAb11 cross-reacts with all four dengue viruses and provides pr...

  14. Production of immunogenic West Nile virus-like particles using a herpes simplex virus 1 recombinant vector.

    Science.gov (United States)

    Taylor, Travis J; Diaz, Fernando; Colgrove, Robert C; Bernard, Kristen A; DeLuca, Neal A; Whelan, Sean P J; Knipe, David M

    2016-09-01

    West Nile virus (WNV) is a flavivirus that swept rapidly across North America in 1999, declined in prevalence, and then resurged in 2012. To date, no vaccine is available to prevent infection in the human population. Herpes simplex virus (HSV) replication-defective vaccine vectors induce a durable immunity characterized by strong antibody and CD8(+) T cell responses even in HSV-immune animals. In this study, a WNV protein expression cassette was optimized for virus-like particle (VLP) production in transfection studies, and the cassette was recombined into an HSV-1 d106-WNV virus vector, which produced extracellular VLPs, as confirmed by immunoelectron microscopy. Immunization of mice with the d106-WNV recombinant vector elicited a specific anti-WNV IgG response. This study highlights the flavivirus coding sequences needed for efficient assembly of virus-like particles. This information will facilitate generation of additional vaccine vectors against other flaviviruses including the recently emerged Zika virus. PMID:27336950

  15. West Nile virus genetic diversity is maintained during transmission by Culex pipiens quinquefasciatus mosquitoes.

    Directory of Open Access Journals (Sweden)

    Doug E Brackney

    Full Text Available Due to error-prone replication, RNA viruses exist within hosts as a heterogeneous population of non-identical, but related viral variants. These populations may undergo bottlenecks during transmission that stochastically reduce variability leading to fitness declines. Such bottlenecks have been documented for several single-host RNA viruses, but their role in the population biology of obligate two-host viruses such as arthropod-borne viruses (arboviruses in vivo is unclear, but of central importance in understanding arbovirus persistence and emergence. Therefore, we tracked the composition of West Nile virus (WNV; Flaviviridae, Flavivirus populations during infection of the vector mosquito, Culex pipiens quinquefasciatus to determine whether WNV populations undergo bottlenecks during transmission by this host. Quantitative, qualitative and phylogenetic analyses of WNV sequences in mosquito midguts, hemolymph and saliva failed to document reductions in genetic diversity during mosquito infection. Further, migration analysis of individual viral variants revealed that while there was some evidence of compartmentalization, anatomical barriers do not impose genetic bottlenecks on WNV populations. Together, these data suggest that the complexity of WNV populations are not significantly diminished during the extrinsic incubation period of mosquitoes.

  16. Climate change impacts on West Nile virus transmission in a global context.

    Science.gov (United States)

    Paz, Shlomit

    2015-04-01

    West Nile virus (WNV), the most widely distributed virus of the encephalitic flaviviruses, is a vector-borne pathogen of global importance. The transmission cycle exists in rural and urban areas where the virus infects birds, humans, horses and other mammals. Multiple factors impact the transmission and distribution of WNV, related to the dynamics and interactions between pathogen, vector, vertebrate hosts and environment. Hence, among other drivers, weather conditions have direct and indirect influences on vector competence (the ability to acquire, maintain and transmit the virus), on the vector population dynamic and on the virus replication rate within the mosquito, which are mostly weather dependent. The importance of climatic factors (temperature, precipitation, relative humidity and winds) as drivers in WNV epidemiology is increasing under conditions of climate change. Indeed, recent changes in climatic conditions, particularly increased ambient temperature and fluctuations in rainfall amounts, contributed to the maintenance (endemization process) of WNV in various locations in southern Europe, western Asia, the eastern Mediterranean, the Canadian Prairies, parts of the USA and Australia. As predictions show that the current trends are expected to continue, for better preparedness, any assessment of future transmission of WNV should take into consideration the impacts of climate change. PMID:25688020

  17. Eastern cottontail rabbits (Sylvilagus floridanus) develop West Nile virus viremias sufficient for infecting select mosquito species.

    Science.gov (United States)

    Tiawsirisup, Sonthaya; Platt, Kenneth B; Tucker, Brad J; Rowley, Wayne A

    2005-01-01

    The potential of the eastern cottontail rabbit (CTR; Sylvilagus floridanus) to contribute to an enzootic West Nile virus (WNV) cycle was demonstrated by characterizing the WNV viremia profile of 15 CTRs and demonstrating that mosquitoes could become infected by feeding on these CTRs. Eight CTRs were infected with a titer of 10(5.0) cell-infectious dose 50% endpoints (CID50s) of WNV (NY99-Crow) by needle and seven CTRs by bite of one or more WNV-infected mosquitoes. There were no marked differences between the WNV viremia profiles of CTRs infected by either method. West Nile virus was detected in serums of all CTRs by 24 h p.i. The daily mean titers of all 15 CTRs on days 1-4 p.i. were 10(4.1+/-0.4), 10(4.7+/-0.3), 10(4.1+/-0.6), and 10(3.7+/-0.6) respectively, declining to 10(1.2+/-0.1) CID50s/ml of serum by day 6 p.i. No virus was detected in the blood of any CTR on day 7 p.i. The average duration of WNV titers of >or=10(4.3) and or=10(4.3) and >10(5.0) were 11.5 +/- 5.5 and 21 +/- 6.0%, respectively. These rates increased to 20.5 +/- 6.4% and 25.0 +/- 3.0% when CTR serum titers were >10(5.0) CID50s/mL. Neither Aedes aegypti (L.) nor Aedes albopictus (Skuse) were infected by feeding on CTRs with titers of 10(5.0) CID50s/ml. None of the CTRs infected by mosquito bite or by needle showed any symptoms of WNV disease. PMID:16417430

  18. West Nile virus seroconversion in penguins after vaccination with a killed virus vaccine or a DNA vaccine.

    Science.gov (United States)

    Davis, Michelle R; Langan, Jennifer N; Johnson, Yvette J; Ritchie, Branson W; Van Bonn, William

    2008-12-01

    To investigate the serologic response of penguins to West Nile virus (WNV) vaccines, four species of exclusively indoor-housed penguins, negative for WNV by serology, were evaluated: Humboldt (Spheniscus humboldti), Magellanic (Spheniscus magellanicus), Gentoo (Pygoscelis papua), and Rockhopper (Eudyptes chrysoscome) penguins. Birds were inoculated with either a killed virus vaccine or a plasmid-mediated DNA WNV vaccine, and postinoculation serology was evaluated. Both vaccines induced seroconversion in all four species, and no adverse reactions were noted. Postvaccination serology results varied across species and vaccine types. However, in all four species, the killed virus vaccine resulted in a greater seroconversion rate than the DNA vaccine and in a significantly shorter time period. Additionally, the duration of the seropositive titer was significantly longer in those birds vaccinated with the killed virus vaccine compared with those vaccinated with the DNA vaccine. A subset of unvaccinated penguins serving as negative controls remained negative throughout the duration of the study despite the presence of WNV in the geographic locations of the study, suggesting that indoor housing may minimize exposure to the virus and may be an additional means of preventing WNV infection in penguins. PMID:19110700

  19. Host genetic risk factors for West Nile virus infection and disease progression.

    Directory of Open Access Journals (Sweden)

    Abigail W Bigham

    Full Text Available West Nile virus (WNV, a category B pathogen endemic in parts of Africa, Asia and Europe, emerged in North America in 1999, and spread rapidly across the continental U.S. Outcomes of infection with WNV range from asymptomatic to severe neuroinvasive disease manifested as encephalitis, paralysis, and/or death. Neuroinvasive WNV disease occurs in less than one percent of cases, and although host genetic factors are thought to influence risk for symptomatic disease, the identity of these factors remains largely unknown. We tested 360 common haplotype tagging and/or functional SNPs in 86 genes that encode key regulators of immune function in 753 individuals infected with WNV including: 422 symptomatic WNV cases and 331 cases with asymptomatic infections. After applying a Bonferroni correction for multiple tests and controlling for population stratification, SNPs in IRF3 (OR 0.54, p = 0.035 and MX1, (OR 0.19, p = 0.014 were associated with symptomatic WNV infection and a single SNP in OAS1 (OR 9.79, p = 0.003 was associated with increased risk for West Nile encephalitis and paralysis (WNE/P. Together, these results suggest that genetic variation in the interferon response pathway is associated with both risk for symptomatic WNV infection and WNV disease progression.

  20. Evaluation of vector competence for West Nile virus in Italian Stegomyia albopicta (=Aedes albopictus) mosquitoes.

    Science.gov (United States)

    Fortuna, C; Remoli, M E; Severini, F; Di Luca, M; Toma, L; Fois, F; Bucci, P; Boccolini, D; Romi, R; Ciufolini, M G

    2015-12-01

    West Nile virus (WNV) is a zoonotic arboviral pathogen transmitted by mosquitoes in a cycle that involves wild birds as reservoir hosts. The virus is responsible for outbreaks of viral encephalitis in humans and horses. In Europe, Culex pipiens (Diptera: Culicidae) is considered to be the main vector of WNV, but other species such as Stegomyia albopicta (=Aedes albopictus) (Diptera: Culicidae) may also act as competent vectors of this virus. Since 2008 human cases of WNV disease have been reported in northeast Italy. In 2011, new areas of southern Italy became involved and a first outbreak of WNV lineage 1 occurred on the island of Sardinia. On the assumption that a potential involvement of St. albopicta in WNV transmission cannot be excluded, and in order to evaluate the competence of this species for the virus, an experimental infection of an St. albopicta laboratory colony, established from mosquitoes collected in Sardinia, was carried out. The results were compared with those obtained in a colony of the main vector Cx. pipiens. The study showed St. albopicta collected on Sardinia to be susceptible to WNV infection, which suggests this Italian mosquito species is able to act as a possible secondary vector, particularly in urban areas where the species reaches high levels of seasonal abundance.

  1. Prior exposure to uninfected mosquitoes enhances mortality in naturally-transmitted West Nile virus infection.

    Directory of Open Access Journals (Sweden)

    Bradley S Schneider

    Full Text Available BACKGROUND: The global emergence of West Nile virus (WNV has highlighted the importance of mosquito-borne viruses. These are inoculated in vector saliva into the vertebrate skin and circulatory system. Arthropod-borne (arboviruses such as WNV are transmitted to vertebrates as an infectious mosquito probes the skin for blood, depositing the virus and saliva into the skin and circulation. Growing evidence has demonstrated that arthropod, and recently mosquito, saliva can have a profound effect on pathogen transmission efficiency, pathogenesis, and disease course. A potentially important aspect of natural infections that has been ignored is that in nature vertebrates are typically exposed to the feeding of uninfected mosquitoes prior to the mosquito that transmits WNV. The possibility that pre-exposure to mosquito saliva might modulate WNV infection was explored. PRINCIPAL FINDINGS: Here we report that sensitization to mosquito saliva exacerbates viral infection. Prior exposure of mice to mosquito feeding resulted in increased mortality following WNV infection. This aggravated disease course was associated with enhanced early viral replication, increased interleukin-10 expression, and elevated influx of WNV-susceptible cell types to the inoculation site. This exacerbated disease course was mimicked by passive transfer of mosquito-sensitized serum. SIGNIFICANCE: This is the first report that sensitization to arthropod saliva can exacerbate arthropod-borne infection, contrary to previous studies with parasite and bacteria infections. This research suggests that in addition to the seroreactivity of the host to virus, it is important to take into account the immune response to vector feeding.

  2. Overwintering of Uranotaenia Unguiculata Adult Females in Central Europe: A Possible Way of Persistence of the Putative New Lineage of West Nile Virus?

    Science.gov (United States)

    Rudolf, Ivo; Šebesta, Oldřich; Straková, Petra; Betášová, Lenka; Blažejová, Hana; VEnclíková, Kristýna; Seidel, Bernhard; Tóth, Sandor; Hubálek, Zdeněk; Schaffner, Francis

    2015-12-01

    We report the overwintering of Uranotaenia unguiculata adult females in Central Europe (Czech Republic, Hungary, Austria). This finding suggests a potential mode of winter persistence of putative novel lineage of West Nile virus in the temperate regions of Europe.

  3. West nile virus in American white pelican chicks: transmission, immunity, and survival

    Science.gov (United States)

    Sovada, Marsha A.; Pietz, Pamela J.; Hofmeister, Erik K.; Bartos, Alisa J.

    2013-01-01

    West Nile virus (WNV) causes significant mortality of American White Pelican chicks at northern plains colonies. We tested oropharyngeal/cloacal swabs from moribund chicks for shed WNV. Such shedding could enable chick-to-chick transmission and help explain why WNV spreads rapidly in colonies. WNV was detected on swabs from 11% of chicks in 2006 and 52% of chicks in 2007; however, viral titers were low. Before onset of WNV mortality, we tested blood from maternal antibodies. Among near-fledged chicks, 41% tested positive for anti-WNV antibodies, indicating that they survived infection. Among years and colonies, cumulative incidence of WNV in chicks varied from 28% to 81%, whereas the proportion of chicks surviving WNV (i.e., seropositive) was 64–75%. Our data revealed that WNV kills chicks that likely would fledge in the absence of WNV, that infection of chicks is pervasive, and that significant numbers of chicks survive infection.

  4. Serologic survey of West Nile virus in horses from Central-West, Northeast and Southeast Brazil

    Science.gov (United States)

    Silva, Jaqueline Raymondi; de Medeiros, Larissa Campos; dos Reis, Vinícius Pinho; Chávez, Juliana Helena; Munhoz, Thiago Demarchi; Borges, Gustavo Puia; Soares, Otavio Augusto Brioschi; de Campos, Carlos Henrique Coelho; Machado, Rosângela Zacarias; Baldani, Cristiane Divan; Silva, Maria Luana Cristiny Rodrigues; Faria, Joice Lara Maia; da Silva, Edson Elias; Figueiredo, Luiz Tadeu Moraes

    2013-01-01

    Since the emergence of West Nile virus (WNV) in North America in 1999, there have been several reports of WNV activity in Central and South American countries. To detect WNV in Brazil, we performed a serological survey of horses from different regions of Brazil using recombinant peptides from domain III of WNV. Positive samples were validated with the neutralisation test. Our results showed that of 79 ELISA-positive horses, nine expressed WNV-specific neutralising antibodies. Eight of the infected horses were from the state of Mato Grosso do Sul and one was from the state of Paraíba. Our results provide additional evidence for the emergence of WNV in Brazil and for its circulation in multiple regions of the country. PMID:24037110

  5. Serologic survey of West Nile virus in horses from Central-West, Northeast and Southeast Brazil

    Directory of Open Access Journals (Sweden)

    Jaqueline Raymondi Silva

    2013-11-01

    Full Text Available Since the emergence of West Nile virus (WNV in North America in 1999, there have been several reports of WNV activity in Central and South American countries. To detect WNV in Brazil, we performed a serological survey of horses from different regions of Brazil using recombinant peptides from domain III of WNV. Positive samples were validated with the neutralisation test. Our results showed that of 79 ELISA-positive horses, nine expressed WNV-specific neutralising antibodies. Eight of the infected horses were from the state of Mato Grosso do Sul and one was from the state of Paraíba. Our results provide additional evidence for the emergence of WNV in Brazil and for its circulation in multiple regions of the country.

  6. Increased frequency of Tim-3 expressing T cells is associated with symptomatic West Nile virus infection.

    Directory of Open Access Journals (Sweden)

    Marion C Lanteri

    Full Text Available More than a decade after West Nile virus (WNV entered North America, and despite a significant increase in reported cases during the 2012 and 2013 seasons, no treatment or vaccine for humans is available. Although antiviral T cells contribute to the control of WNV, little is known about their regulation during acute infection. We analyzed the expression of Tim-3 and PD-1, two recently identified T cell negative immune checkpoint receptors, over the course of WNV infection. Symptomatic WNV+ donors exhibited higher frequencies of Tim-3+ cells than asymptomatic subjects within naïve/early differentiated CD28+/-CD57-CD4+ and differentiated CD28-CD57-CD8+ T cells. Our study links Tim-3-expression on T cells during acute WNV infection with the development of symptomatic disease, suggesting Tim-3 and its ligands could be targeted therapeutically to alter anti-WNV immunity and improve disease outcome.

  7. Assessment of Arbovirus Surveillance 13 Years after Introduction of West Nile Virus, United States.

    Science.gov (United States)

    Hadler, James L; Patel, Dhara; Nasci, Roger S; Petersen, Lyle R; Hughes, James M; Bradley, Kristy; Etkind, Paul; Kan, Lilly; Engel, Jeffrey

    2015-07-01

    Before 1999, the United States had no appropriated funding for arboviral surveillance, and many states conducted no such surveillance. After emergence of West Nile virus (WNV), federal funding was distributed to state and selected local health departments to build WNV surveillance systems. The Council of State and Territorial Epidemiologists conducted assessments of surveillance capacity of resulting systems in 2004 and in 2012; the assessment in 2012 was conducted after a 61% decrease in federal funding. In 2004, nearly all states and assessed local health departments had well-developed animal, mosquito, and human surveillance systems to monitor WNV activity and anticipate outbreaks. In 2012, many health departments had decreased mosquito surveillance and laboratory testing capacity and had no systematic disease-based surveillance for other arboviruses. Arboviral surveillance in many states might no longer be sufficient to rapidly detect and provide information needed to fully respond to WNV outbreaks and other arboviral threats (e.g., dengue, chikungunya).

  8. Vector competence of three North American strains of Aedes albopictus for West Nile virus.

    Science.gov (United States)

    Sardelis, Michael R; Turell, Michael J; O'Guinn, Monica L; Andre, Richard G; Roberts, Donald R

    2002-12-01

    To evaluate the potential for North American (NA) Aedes albopictus to transmit West Nile virus (WN), mosquito strains derived from 3 NA sources (Frederick County, Maryland, FRED strain; Cheverly, MD, CHEV strain; Chambers and Liberty counties, Texas, TAMU strain) were tested. These strains were tested along with a previously tested strain from a Hawaiian source (OAHU strain). Mosquitoes were fed on 2- to 3-day-old chickens previously inoculated with a New York strain (Crow 397-99) of WN. All of the NA strains were competent laboratory vectors of WN, with transmission rates of 36, 50, 83, and 92% for the FRED, CHEV, OAHU, and TAMU strains, respectively. The extrinsic incubation period for WN in Ae. albopictus held at 26 degrees C was estimated to be 10 days. Based on efficiency of viral transmission, evidence of natural infection, bionomics, and distribution, Ae. albopictus could be an important bridge vector of WN in the southeastern USA.

  9. Emergency department management of mosquito-borne illness: malaria, dengue, and West Nile virus.

    Science.gov (United States)

    Caraballo, Hector; King, Kevin

    2014-05-01

    Up to 700 million people are infected and more than a million die each year from mosquito-borne illness. While the vast majority of cases occur in endemic tropical and subtropical regions, international travel and migration patterns have increased their prevalence in North America. This review discusses the diagnosis and treatment of the 3 most common mosquito-borne illnesses seen in the United States: Plasmodium falciparum malaria, dengue, and West Nile virus. With no pathognomonic findings, it is critical that emergency clinicians in nonendemic areas maintain a high index of suspicion, conduct a thorough history/travel history, and interpret indirect findings to initiate prompt and appropriate treatment. This review gathers the best evidence from international public health resources, surveillance studies, guidelines, and academic research to give emergency clinicians tools to combat these potentially lethal infections. PMID:25207355

  10. The use of early summer mosquito surveillance to predict late summer West Nile virus activity

    Science.gov (United States)

    Ginsberg, Howard S.; Rochlin, Ilia; Campbell, Scott R.

    2010-01-01

    Utility of early-season mosquito surveillance to predict West Nile virus activity in late summer was assessed in Suffolk County, NY. Dry ice-baited CDC miniature light traps paired with gravid traps were set weekly. Maximum-likelihood estimates of WNV positivity, minimum infection rates, and % positive pools were generally well correlated. However, positivity in gravid traps was not correlated with positivity in CDC light traps. The best early-season predictors of WNV activity in late summer (estimated using maximum-likelihood estimates of Culex positivity in August and September) were early date of first positive pool, low numbers of mosquitoes in July, and low numbers of mosquito species in July. These results suggest that early-season entomological samples can be used to predict WNV activity later in the summer, when most human cases are acquired. Additional research is needed to establish which surveillance variables are most predictive and to characterize the reliability of the predictions.

  11. Mosquito Surveillance for 15 Years Reveals High Genetic Diversity Among West Nile Viruses in Israel.

    Science.gov (United States)

    Lustig, Yaniv; Hindiyeh, Musa; Orshan, Laor; Weiss, Leah; Koren, Ravit; Katz-Likvornik, Shiri; Zadka, Hila; Glatman-Freedman, Aharona; Mendelson, Ella; Shulman, Lester M

    2016-04-01

    West Nile Virus (WNV) is endemic in Israel and has been the cause of several outbreaks in recent years. In 2000, a countrywide mosquito survey was established to monitor WNV activity and characterize viral genotypes in Israel. We analyzed data from 7135 pools containing 277 186 mosquitoes collected over the past 15 years and, here, report partial sequences of WNV genomes obtained from 102 of the 336 positive mosquito pools. Phylogenetic analysis demonstrated that cluster 4 and the Mediterranean and Eastern European subtypes of cluster 2 within WNV lineage 1 circulated in Israel, as did WNV lineage 2, highlighting a high genetic diversity of WNV genotypes in our region. As a major crossroads for bird migration between Africa and Eurasia and with a long history of human infection, Israel serves as a resource hub for WNV in Africa and Eurasia and provides valuable information on WNV circulation in these regions. PMID:26597260

  12. West Nile Virus Viremia in Eastern Chipmunks (Tamias striatus) Sufficient for Infecting Different Mosquitoes

    OpenAIRE

    Platt, Kenneth B.; Tucker, Bradley J.; Halbur, Patrick G.; Tiawsirisup, Sonthaya; Blitvich, Bradley J; Fabiosa, Flor G.; BARTHOLOMAY, LYRIC C.; Rowley, Wayne A.

    2007-01-01

    In eastern chipmunks (Tamias striatus) inoculated intramuscularly with 101.5 to 105.7 PFU of West Nile virus (WNV), serum titers developed sufficient to infect Aedes triseriatus (Say), Ae. vexans (Meigen), and Culex pipiens (L.). Mean titers (95% confidence interval) of 8 chipmunks were 103.9(3.3–4.5), 106.7(6.4–7.0), and 105.8(4.1–7.5) PFU/mL on days 1–3 postinoculation (p.i.) and 105.8 PFU/mL in 1 chipmunk on day 4 p.i. Mean estimated days that WNV titers were >104.8 and >105.6 were 1.7 (1....

  13. Comparing competitive fitness of West Nile virus strains in avian and mosquito hosts.

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    Gabriella Worwa

    Full Text Available Enzootic transmission of West Nile virus (WNV; Flaviviridae, Flavivirus involves various species of birds and ornithophilic mosquitoes. Single nucleotide substitutions in the WNV genome may impact viral fitness necessary for WNV adaptation and evolution as previously shown for the WN02 genotype. In an effort to study phenotypic change, we developed an in vivo fitness competition model in two biologically relevant hosts for WNV. The House Finch (HOFI; Haemorhous mexicanus and Culex tarsalis mosquitoes represent moderately susceptible hosts for WNV, are highly abundant in Western North America and frequently are infected with WNV in nature. Herein, we inoculated HOFIs and Cx. tarsalis competitively (dually and singly with infectious-clone derived viruses of the founding California isolate COAV997-2003 (COAV997-IC, the founding North American isolate NY99 (NY99-IC, and a 2004 field isolate from California (CA-04, and compared the replicative capacities (fitness of these viruses to a genetically marked virus of COAV997 (COAV997-5nt by measuring RNA copy numbers. COAV997 and COAV997-5nt exhibited neutral fitness in HOFIs and Cx. tarsalis, and the temperature-sensitive phenotype of COAV997 did not affect replication in HOFIs as none of the infected birds became febrile. The NY99 and CA-04 isolates demonstrated elevated fitness in HOFIs compared to COAV997-5nt, whereas all viruses replicated to similar titers and RNA copies in Cx. tarsalis, and the only fitness differences were related to infection rates. Our data demonstrated that competitive replication allows for the sensitive comparison of fitness differences among two genetically closely related viruses using relevant hosts of WNV while eliminating host-to-host differences. In conclusion, our approach may be helpful in understanding the extent of phenotypic change in fitness associated with genetic changes in WNV.

  14. Pathogenesis of West Nile virus lineage 1 and 2 in experimentally infected large falcons.

    Science.gov (United States)

    Ziegler, Ute; Angenvoort, Joke; Fischer, Dominik; Fast, Christine; Eiden, Martin; Rodriguez, Ariel V; Revilla-Fernández, Sandra; Nowotny, Norbert; de la Fuente, Jorge García; Lierz, Michael; Groschup, Martin H

    2013-01-25

    West Nile virus (WNV) is a zoonotic flavivirus that is transmitted by blood-suckling mosquitoes with birds serving as the primary vertebrate reservoir hosts (enzootic cycle). Some bird species like ravens, raptors and jays are highly susceptible and develop deadly encephalitis while others are infected subclinically only. Birds of prey are highly susceptible and show substantial mortality rates following infection. To investigate the WNV pathogenesis in falcons we inoculated twelve large falcons, 6 birds per group, subcutaneously with viruses belonging to two different lineages (lineage 1 strain NY 99 and lineage 2 strain Austria). Three different infection doses were utilized: low (approx. 500 TCID50), intermediate (approx. 4 log10 TCID50) and high (approx. 6 log10 TCID50). Clinical signs were monitored during the course of the experiments lasting 14 and 21 days. All falcons developed viremia for two weeks and shed virus for almost the same period of time. Using quantitative real-time RT-PCR WNV was detected in blood, in cloacal and oropharyngeal swabs and following euthanasia and necropsy of the animals in a variety of neuronal and extraneuronal organs. Antibodies to WNV were first time detected by ELISA and neutralization assay after 6 days post infection (dpi). Pathological findings consistently included splenomegaly, non-suppurative myocarditis, meningoencephalitis and vasculitis. By immunohistochemistry WNV-antigens were demonstrated intralesionally. These results impressively illustrate the devastating and possibly deadly effects of WNV infection in falcons, independent of the genetic lineage and dose of the challenge virus used. Due to the relatively high virus load and long duration of viremia falcons may also be considered competent WNV amplifying hosts, and thus may play a role in the transmission cycle of this zoonotic virus. PMID:22909991

  15. Parasitic Cowbirds have increased immunity to West Nile and other mosquitoborne encephalitis viruses

    Science.gov (United States)

    Reisen, W.K.; Hahn, D.C.

    2006-01-01

    The rapid geographic spread of West Nile Virus [WNV, Flaviviridae, Flavivirus] across the United States has stimulated interest in comparative host infection studies of avian species to delineate competent reservoir hosts critical for viral amplification. Striking taxonomic differences in avian susceptibility have been noted, offering the opportunity to strategically select species on the basis of life history traits to examine aspects of pathogen virulence or host immunity. We hypothesized that avian brood parasites would show increased resistance to pathogens compared to related taxa, because they have been exposed in their evolutionary history to a wide array of infectious organisms from their different parenting species. The Brown-headed Cowbird (Molothrus ater) is a generalist brood parasite that parasitizes 200+ North American species. Elevated exposure to other species? parasites may have created an unusual degree of pathogen resistance. We compared the relative susceptibility of adult cowbirds to three closely-related non-parasitic species, Red-winged blackbirds, Tricolored blackbirds and Brewer?s blackbirds, to invading NY99 strain of WNV that is highly virulent for many passeriform birds. Previously we had experimentally infected these species with two North American mosquitoborne encephalitis viruses, western equine encephalomyelitis virus [WEEV, Togaviridae, Alphavirus] and St. Louis encephalitis virus [SLEV, Flaviviridae, Flavivirus]. Our results showed that cowbirds exhibited significantly lower viremia responses against all three viruses as well as after co-infection with both WEEV and WNV than did the three related, non-parasitic species. These data supported our hypothesis and indicated that cowbirds were more resistant to infection to both native and introduced viruses.

  16. The role of temperature on the spatiotemporal distribution of West Nile virus in the United States

    Science.gov (United States)

    Horton, D. E.; Kilpatrick, A. M.; Ruybal, J.; Diffenbaugh, N. S.

    2012-12-01

    Determining the relationship between climatological factors and vector-borne pathogens remains a critical challenge. The recent arrival of the West Nile virus (WNV) to the Americas, coupled with an extensive climatological and disease observation network, offers the potential to improve our mechanistic understanding of climate's influence on vector-borne disease transmission. Since its introduction to the Americas in the summer of 1999, the West Nile Virus (WNV) has rapidly spread from coastal New York State, across the North American continent, and into Central and South America. To date, 13,385 cases of WNV-induced human neuroinvasive disease have been reported to the U.S. Centers for Disease Control, with approximately 1,267 fatalities attributed to viral infection (as of 31 July 2012). Of those infected, severe symptoms develop in only ~1 in 150 people, suggesting that the total U.S. population infected with WNV is on the order of 2 million. The transmission of WNV is predominantly vector-borne, with three mosquitoes of the Culex genus, pipiens, tarsalis, and quinquefasciatus, largely responsible for the spread of the pathogen between avian and human hosts and across the contiguous United States. In this contribution, we synthesize laboratory and local-scale field studies of the Culex vectors with observed and modeled climatological data in an attempt to determine the mechanistic influence of temperature on the spatiotemporal distribution of WNV incidence across the United States. Our preliminary results suggest that many of the physiological factors that determine the transmission intensity of WNV, including mosquito biting rate, vector competence, infection transition rate, and mosquito mortality rate, demonstrate direct temperature dependencies. Based on these results, we utilize bias-corrected outputs from late-20th and mid-21st century CMIP5 simulations to examine the influence of temperature on the distribution of WNV relative to other factors and to

  17. A GIS-driven integrated real-time surveillance pilot system for national West Nile virus dead bird surveillance in Canada

    Directory of Open Access Journals (Sweden)

    Aramini Jeff

    2006-04-01

    Full Text Available Abstract Background An extensive West Nile virus surveillance program of dead birds, mosquitoes, horses, and human infection has been launched as a result of West Nile virus first being reported in Canada in 2001. Some desktop and web GIS have been applied to West Nile virus dead bird surveillance. There have been urgent needs for a comprehensive GIS services and real-time surveillance. Results A pilot system was developed to integrate real-time surveillance, real-time GIS, and Open GIS technology in order to enhance West Nile virus dead bird surveillance in Canada. Driven and linked by the newly developed real-time web GIS technology, this integrated real-time surveillance system includes conventional real-time web-based surveillance components, integrated real-time GIS components, and integrated Open GIS components. The pilot system identified the major GIS functions and capacities that may be important to public health surveillance. The six web GIS clients provide a wide range of GIS tools for public health surveillance. The pilot system has been serving Canadian national West Nile virus dead bird surveillance since 2005 and is adaptable to serve other disease surveillance. Conclusion This pilot system has streamlined, enriched and enhanced national West Nile virus dead bird surveillance in Canada, improved productivity, and reduced operation cost. Its real-time GIS technology, static map technology, WMS integration, and its integration with non-GIS real-time surveillance system made this pilot system unique in surveillance and public health GIS.

  18. 西尼罗河病毒病的研究进展%Advancement of West Nile Virus Disease Research

    Institute of Scientific and Technical Information of China (English)

    吕喆; 于亚洲; 胡桂学; 赵哲

    2012-01-01

    西尼罗河病毒病是由西尼罗河病毒(west Nilevims,wNv)引起的一种人畜共患传染病,病原是一种虫媒病毒,可导致西尼罗河热和致死性的西尼罗河脑炎。自发现以来,西尼罗河病毒病曾在世界上多个国家暴发,给畜牧业和人类生命安全造成了巨大的危害。我国目前尚无该病的发生,但是防治技术储备是必要的。本文对西尼罗河病毒病的流行病学、病原学、致病机制、临床症状和病理剖检变化、诊断方法和候选疗法进行综述,为西尼罗河病毒病的防控提供资料。%The West Nile virus disease is a zoonoses which caused by West Nile virus (WNV). WNV is an arbovirus and leads to West Nile heat and lethal West Nile encephalitis. Since discovered, the disease had been already trigger the world countries outbreak. The disease gives raise great threat to human lives and the development of animal husbandry. At present, although it never happened in our country, the technical reserve is necessary. This review describes the current state of knowledge on epidemiology, pathogenesis, pathopoiesis mechanism, clinical symptoms and pathological changes, diagnostic methods candidate therapies and prospects to provide related information for prevention and control of West Nile virus disease.

  19. West Nile virus and its theories, a big puzzle in Mexico and Latin America

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    Darwin Elizondo-Quiroga

    2013-01-01

    Full Text Available It has been 13 years since the first outbreak of West Nile Virus (WNV occurred in the Americas. Since then, thousands of human cases have been reported in the United States. In contrast, there has not yet been an outbreak of WNV in any Latin American countries, including Mexico where <20 cases have been reported. We aimed to review publications to gather the main theories related to the fact that not all the countries of the continent reported human cases or that they have reported few cases since the introduction of WNV in the Western Hemisphere. We identified relevant publications using the PubMed database. Furthermore, we present on-line published information from Mexico. We found that researchers have tried to explain this phenomenon using several theories, like pre-existing antibodies against a heterotypical virus that have conferred cross protection in the population. Another explanation is that the strains circulating in Latin America are attenuated or that they came from a different origin of introduction in the continent. Another theory is that a conclusive diagnostic in regions where more than one Flavivirus is circulating results in cross-reaction in serological tests. Probably the sum of factors described by researchers in these theories in order to explain the behavior of the virus has resulted in the low number of reported cases in Latin America.

  20. Plant-made vaccines against West Nile virus are potent, safe, and economically feasible.

    Science.gov (United States)

    Chen, Qiang

    2015-05-01

    The threat of West Nile virus (WNV) epidemics with increasingly severe neuroinvasive infections demands the development and licensing of effective vaccines. To date, vaccine candidates based on inactivated, live-attenuated, or chimeric virus, and viral DNA and WNV protein subunits have been developed. Some have been approved for veterinary use or are under clinical investigation, yet no vaccine has been licensed for human use. Reaching the milestone of a commercialized human vaccine, however, may largely depend on the economics of vaccine production. Analysis suggests that currently only novel low-cost production technologies would allow vaccination to outcompete the cost of surveillance and clinical treatment. Here, we review progress using plants to address the economic challenges of WNV vaccine production. The advantages of plants as hosts for vaccine production in cost, speed and scalability, especially those of viral vector-based transient expression systems, are discussed. The progress in developing WNV subunit vaccines in plants is reviewed within the context of their expression, characterization, downstream processing, and immunogenicity in animal models. The development of vaccines based on enveloped and non-enveloped virus-like particles is also discussed. These advancements suggest that plants may provide a production platform that offers potent, safe and affordable human vaccines against WNV.

  1. Sequence-Specific Fidelity Alterations Associated with West Nile Virus Attenuation in Mosquitoes.

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    Greta A Van Slyke

    2015-06-01

    Full Text Available High rates of error-prone replication result in the rapid accumulation of genetic diversity of RNA viruses. Recent studies suggest that mutation rates are selected for optimal viral fitness and that modest variations in replicase fidelity may be associated with viral attenuation. Arthropod-borne viruses (arboviruses are unique in their requirement for host cycling and may necessitate substantial genetic and phenotypic plasticity. In order to more thoroughly investigate the correlates, mechanisms and consequences of arbovirus fidelity, we selected fidelity variants of West Nile virus (WNV; Flaviviridae, Flavivirus utilizing selection in the presence of a mutagen. We identified two mutations in the WNV RNA-dependent RNA polymerase associated with increased fidelity, V793I and G806R, and a single mutation in the WNV methyltransferase, T248I, associated with decreased fidelity. Both deep-sequencing and in vitro biochemical assays confirmed strain-specific differences in both fidelity and mutational bias. WNV fidelity variants demonstrated host-specific alterations to replicative fitness in vitro, with modest attenuation in mosquito but not vertebrate cell culture. Experimental infections of colonized and field populations of Cx. quinquefaciatus demonstrated that WNV fidelity alterations are associated with a significantly impaired capacity to establish viable infections in mosquitoes. Taken together, these studies (i demonstrate the importance of allosteric interactions in regulating mutation rates, (ii establish that mutational spectra can be both sequence and strain-dependent, and (iii display the profound phenotypic consequences associated with altered replication complex function of flaviviruses.

  2. West Nile virus transmission: results from the integrated surveillance system in Italy, 2008 to 2015

    Science.gov (United States)

    Rizzo, Caterina; Napoli, Christian; Venturi, Giulietta; Pupella, Simonetta; Lombardini, Letizia; Calistri, Paolo; Monaco, Federica; Cagarelli, Roberto; Angelini, Paola; Bellini, Romeo; Tamba, Marco; Piatti, Alessandra; Russo, Francesca; Palù, Giorgio; Chiari, Mario; Lavazza, Antonio; Bella, Antonino

    2016-01-01

    In Italy a national Plan for the surveillance of imported and autochthonous human vector-borne diseases (chikungunya, dengue, Zika virus disease and West Nile virus (WNV) disease) that integrates human and veterinary (animals and vectors) surveillance, is issued and revised annually according with the observed epidemiological changes. Here we describe results of the WNV integrated veterinary and human surveillance systems in Italy from 2008 to 2015. A real time data exchange protocol is in place between the surveillance systems to rapidly identify occurrence of human and animal cases and to define and update the map of affected areas i.e. provinces during the vector activity period from June to October. WNV continues to cause severe illnesses in Italy during every transmission season, albeit cases are sporadic and the epidemiology varies by virus lineage and geographic area. The integration of surveillance activities and a multidisciplinary approach made it possible and have been fundamental in supporting implementation of and/or strengthening preventive measures aimed at reducing the risk of transmission of WNV trough blood, tissues and organ donation and to implementing further measures for vector control. PMID:27684046

  3. Seroconversion for west Nile and St. Louis encephalitis viruses among sentinel horses in Colombia

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    Salim Mattar

    2011-12-01

    Full Text Available We prospectively sampled flavivirus-naïve horses in northern Colombia to detect West Nile virus (WNV and St. Louis encephalitis virus (SLEV seroconversion events, which would indicate the current circulation of these viruses. Overall, 331 (34.1% of the 971 horses screened were positive for past infection with flaviviruses upon initial sampling in July 2006. During the 12-month study from July 2006-June 2007, 33 WNV seroconversions and 14 SLEV seroconversions were detected, most of which occurred in the department of Bolivar. The seroconversion rates of horses in Bolivar for the period of March-June 2007 reached 12.4% for WNV and 6.7% for SLEV. These results comprise the first serologic evidence of SLEV circulation in Colombia. None of the horses sampled developed symptoms of encephalitis within three years of initial sampling. Using seroconversions in sentinel horses, we demonstrated an active circulation of WNV and SLEV in northern Colombia, particularly in the department of Bolivar. The absence of WNV-attributed equine or human disease in Colombia and elsewhere in the Caribbean Basin remains a topic of debate and speculation.

  4. West Nile virus infection causes endocytosis of a specific subset of tight junction membrane proteins.

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    Zaikun Xu

    Full Text Available West Nile virus (WNV is a blood-borne pathogen that causes systemic infections and serious neurological disease in human and animals. The most common route of infection is mosquito bites and therefore, the virus must cross a number of polarized cell layers to gain access to organ tissue and the central nervous system. Resistance to trans-cellular movement of macromolecules between epithelial and endothelial cells is mediated by tight junction complexes. While a number of recent studies have documented that WNV infection negatively impacts the barrier function of tight junctions, the intracellular mechanism by which this occurs is poorly understood. In the present study, we report that endocytosis of a subset of tight junction membrane proteins including claudin-1 and JAM-1 occurs in WNV infected epithelial and endothelial cells. This process, which ultimately results in lysosomal degradation of the proteins, is dependent on the GTPase dynamin and microtubule-based transport. Finally, infection of polarized cells with the related flavivirus, Dengue virus-2, did not result in significant loss of tight junction membrane proteins. These results suggest that neurotropic flaviviruses such as WNV modulate the host cell environment differently than hemorrhagic flaviviruses and thus may have implications for understanding the molecular basis for neuroinvasion.

  5. West Nile virus transmission: results from the integrated surveillance system in Italy, 2008 to 2015.

    Science.gov (United States)

    Rizzo, Caterina; Napoli, Christian; Venturi, Giulietta; Pupella, Simonetta; Lombardini, Letizia; Calistri, Paolo; Monaco, Federica; Cagarelli, Roberto; Angelini, Paola; Bellini, Romeo; Tamba, Marco; Piatti, Alessandra; Russo, Francesca; Palù, Giorgio; Chiari, Mario; Lavazza, Antonio; Bella, Antonino

    2016-09-15

    In Italy a national Plan for the surveillance of imported and autochthonous human vector-borne diseases (chikungunya, dengue, Zika virus disease and West Nile virus (WNV) disease) that integrates human and veterinary (animals and vectors) surveillance, is issued and revised annually according with the observed epidemiological changes. Here we describe results of the WNV integrated veterinary and human surveillance systems in Italy from 2008 to 2015. A real time data exchange protocol is in place between the surveillance systems to rapidly identify occurrence of human and animal cases and to define and update the map of affected areas i.e. provinces during the vector activity period from June to October. WNV continues to cause severe illnesses in Italy during every transmission season, albeit cases are sporadic and the epidemiology varies by virus lineage and geographic area. The integration of surveillance activities and a multidisciplinary approach made it possible and have been fundamental in supporting implementation of and/or strengthening preventive measures aimed at reducing the risk of transmission of WNV trough blood, tissues and organ donation and to implementing further measures for vector control.

  6. Use of Competition ELISA for Monitoring of West Nile Virus Infections in Horses in Germany

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    Martin H. Groschup

    2013-07-01

    Full Text Available West Nile virus (WNV is a mosquito-borne viral pathogen of global importance and is considered to be the most widespread flavivirus in the World. Horses, as dead-end hosts, can be infected by bridge mosquito vectors and undergo either subclinical infections or develop severe neurological diseases. The aim of this study was to detect WNV specific antibodies in horses in Germany as an indicator for an endemic circulation of WNV. Sera from more than 5,000 horses (primarily fallen stock animals were collected in eight different federal states of Germany from 2010 to 2012. Sera were screened by a competitive ELISA and positive reactions were verified by an indirect IgM ELISA and/or by virus neutralization tests (VNT for WNV and Tick-borne encephalitis virus (TBEV in order to exclude cross-reacting antibody reactions. In essence WNV specific antibodies could not be detected in any of the horse sera. Not surprisingly, a small number of sera contained antibodies against TBEV. It is noteworthy that equine sera were often collected from horse carcasses and therefore were of poor quality. Nonetheless, these sera were still suitable for WNV ELISA testing, i.e., they did not produce a high background reaction which is a frequently observed phenomenon. According to these data there is no evidence for indigenous WNV infections in horses in Germany at present.

  7. Neutralizing activities of human immunoglobulin derived from donors in Japan against mosquito-borne flaviviruses, Japanese encephalitis virus, West Nile virus, and dengue virus

    Science.gov (United States)

    Yunoki, Mikihiro; Kurosu, Takeshi; Koketsu, Ritsuko Kubota; Takahashi, Kazuo; Okuno, Yoshinobu; Ikuta, Kazuyoshi

    2016-01-01

    Japanese encephalitis virus (JEV), West Nile virus (WNV), and dengue virus (DenV) are causal agents of Japanese encephalitis, West Nile fever, and dengue fever, respectively. JEV is considered to be indigenized and widespread in Japan, whereas WNV and DenV are not indigenized in Japan. Globulin products seem to reflect the status of the donor population according to antivirus neutralization activity. However, the anti-JEV, -WNV, and -DenV neutralization activities of globulin products derived from donors in Japan have not been clarified. Furthermore, potential candidates for the development of an effective immunotherapeutic drug for encephalitis caused by JEV, WNV, or DenV have also not been identified. Therefore, the aim of this study was to determine the overall status of the donor population in Japan based on globulin products by evaluating anti-JEV, -WNV, and -DenV neutralizing activities of intravenous immunoglobulin. Overall, intravenous immunoglobulin products showed stable neutralizing activity against JEV but showed no or only weak activity against WNV or DenV. These results suggest that the epidemiological level against WNV and DenV in the donor population of Japan is still low, suggesting that these viruses are not yet indigenized. In addition, JEV vaccinations and/or infections in the donor population do not induce a cross-reactive antibody against WNV. PMID:27462140

  8. Neutralizing activities of human immunoglobulin derived from donors in Japan against mosquito-borne flaviviruses, Japanese encephalitis virus, West Nile virus, and dengue virus.

    Science.gov (United States)

    Yunoki, Mikihiro; Kurosu, Takeshi; Koketsu, Ritsuko Kubota; Takahashi, Kazuo; Okuno, Yoshinobu; Ikuta, Kazuyoshi

    2016-01-01

    Japanese encephalitis virus (JEV), West Nile virus (WNV), and dengue virus (DenV) are causal agents of Japanese encephalitis, West Nile fever, and dengue fever, respectively. JEV is considered to be indigenized and widespread in Japan, whereas WNV and DenV are not indigenized in Japan. Globulin products seem to reflect the status of the donor population according to antivirus neutralization activity. However, the anti-JEV, -WNV, and -DenV neutralization activities of globulin products derived from donors in Japan have not been clarified. Furthermore, potential candidates for the development of an effective immunotherapeutic drug for encephalitis caused by JEV, WNV, or DenV have also not been identified. Therefore, the aim of this study was to determine the overall status of the donor population in Japan based on globulin products by evaluating anti-JEV, -WNV, and -DenV neutralizing activities of intravenous immunoglobulin. Overall, intravenous immunoglobulin products showed stable neutralizing activity against JEV but showed no or only weak activity against WNV or DenV. These results suggest that the epidemiological level against WNV and DenV in the donor population of Japan is still low, suggesting that these viruses are not yet indigenized. In addition, JEV vaccinations and/or infections in the donor population do not induce a cross-reactive antibody against WNV. PMID:27462140

  9. Experimental West Nile Virus Infection in Rabbits: An Alternative Model for Studying Induction of Disease and Virus Control

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    Willy W. Suen

    2015-07-01

    Full Text Available The economic impact of non-lethal human and equine West Nile virus (WNV disease is substantial, since it is the most common presentation of the infection. Experimental infection with virulent WNV strains in the mouse and hamster models frequently results in severe neural infection and moderate to high mortality, both of which are not representative features of most human and equine infections. We have established a rabbit model for investigating pathogenesis and immune response of non-lethal WNV infection. Two species of rabbits, New Zealand White (Oryctolagus cuniculus and North American cottontail (Sylvilagus sp., were experimentally infected with virulent WNV and Murray Valley encephalitis virus strains. Infected rabbits exhibited a consistently resistant phenotype, with evidence of low viremia, minimal-absent neural infection, mild-moderate neuropathology, and the lack of mortality, even though productive virus replication occurred in the draining lymph node. The kinetics of anti-WNV neutralizing antibody response was comparable to that commonly seen in infected horses and humans. This may be explained by the early IFNα/β and/or γ response evident in the draining popliteal lymph node. Given this similarity to the human and equine disease, immunocompetent rabbits are, therefore, a valuable animal model for investigating various aspects of non-lethal WNV infections.

  10. Experimental West Nile Virus Infection in Rabbits: An Alternative Model for Studying Induction of Disease and Virus Control.

    Science.gov (United States)

    Suen, Willy W; Uddin, Muhammad J; Wang, Wenqi; Brown, Vienna; Adney, Danielle R; Broad, Nicole; Prow, Natalie A; Bowen, Richard A; Hall, Roy A; Bielefeldt-Ohmann, Helle

    2015-01-01

    The economic impact of non-lethal human and equine West Nile virus (WNV) disease is substantial, since it is the most common presentation of the infection. Experimental infection with virulent WNV strains in the mouse and hamster models frequently results in severe neural infection and moderate to high mortality, both of which are not representative features of most human and equine infections. We have established a rabbit model for investigating pathogenesis and immune response of non-lethal WNV infection. Two species of rabbits, New Zealand White (Oryctolagus cuniculus) and North American cottontail (Sylvilagus sp.), were experimentally infected with virulent WNV and Murray Valley encephalitis virus strains. Infected rabbits exhibited a consistently resistant phenotype, with evidence of low viremia, minimal-absent neural infection, mild-moderate neuropathology, and the lack of mortality, even though productive virus replication occurred in the draining lymph node. The kinetics of anti-WNV neutralizing antibody response was comparable to that commonly seen in infected horses and humans. This may be explained by the early IFNα/β and/or γ response evident in the draining popliteal lymph node. Given this similarity to the human and equine disease, immunocompetent rabbits are, therefore, a valuable animal model for investigating various aspects of non-lethal WNV infections. PMID:26184326

  11. Antecedent avian immunity limits tangential transmission of West Nile virus to humans.

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    Jennifer L Kwan

    Full Text Available BACKGROUND: West Nile virus (WNV is a mosquito-borne flavivirus maintained and amplified among birds and tangentially transmitted to humans and horses which may develop terminal neuroinvasive disease. Outbreaks typically have a three-year pattern of silent introduction, rapid amplification and subsidence, followed by intermittent recrudescence. Our hypothesis that amplification to outbreak levels is contingent upon antecedent seroprevalence within maintenance host populations was tested by tracking WNV transmission in Los Angeles, California from 2003 through 2011. METHODS: Prevalence of antibodies against WNV was monitored weekly in House Finches and House Sparrows. Tangential or spillover transmission was measured by seroconversions in sentinel chickens and by the number of West Nile neuroinvasive disease (WNND cases reported to the Los Angeles County Department of Public Health. RESULTS: Elevated seroprevalence in these avian populations was associated with the subsidence of outbreaks and in the antecedent dampening of amplification during succeeding years. Dilution of seroprevalence by recruitment resulted in the progressive loss of herd immunity following the 2004 outbreak, leading to recrudescence during 2008 and 2011. WNV appeared to be a significant cause of death in these avian species, because the survivorship of antibody positive birds significantly exceeded that of antibody negative birds. Cross-correlation analysis showed that seroprevalence was negatively correlated prior to the onset of human cases and then positively correlated, peaking at 4-6 weeks after the onset of tangential transmission. Antecedent seroprevalence during winter (Jan - Mar was negatively correlated with the number of WNND cases during the succeeding summer (Jul-Sep. CONCLUSIONS: Herd immunity levels within after hatching year avian maintenance host populations <10% during the antecedent late winter and spring period were followed on three occasions by

  12. Survey for West Nile virus antibodies in wild ducks, 2004-06, USA

    Science.gov (United States)

    Hofmeister, Erik K.; Jankowski, Mark D.; Goldberg, Diana R.; Franson, J. Christian

    2016-01-01

    Detection of West Nile virus (WNV) in ducks has been reported in North America in isolated cases of mortality in wild waterbirds and following outbreaks in farmed ducks. Although the virus has been noted as an apparent incidental finding in several species of ducks, little is known about the prevalence of exposure or the outcome of infection with WNV in wild ducks in North America. From 2004–06, we collected sera from 1,406 wild-caught American Wigeon (Anas americana), Mallard (Anas platyrhynchos), and Northern Pintail (Anas acuta) ducks at national wildlife refuges (NWRs) in North Dakota and Wood Ducks (Aix sponsa) at NWRs in South Carolina and Tennessee. We measured the prevalence of previous exposure to WNV in these ducks by measuring WNV antibodies and evaluated variation in exposure among species, age, and year. Additionally, we evaluated the performance of a commercial antibody to wild bird immunoglobulin in duck species that varied in their phylogenetic relatedness to the bird species the antibody was directed against. As determined by a screening immunoassay and a confirmatory plaque reduction neutralization assay, the prevalence of WNV antibody was 10%. In light of experimental studies that show ducks to be relatively resistant to mortality caused by WNV, the antibody prevalence we detected suggests that wild ducks may be less-frequently exposed to WNV than expected for birds inhabiting wetlands where they may acquire infection from mosquitoes.

  13. Oral and parenteral immunization of chickens (Gallus gallus) against West Nile virus with recombinant envelope protein

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    Fassbinder-Orth, C. A.; Hofmeister, E.K.; Weeks-Levy, C.; Karasov, W.H.

    2009-01-01

    West Nile virus (WNV) causes morbidity and mortality in humans, horses, and in more than 315 bird species in North America. Currently approved WNV vaccines are designed for parenteral administration and, as yet, no effective oral WNV vaccines have been developed. WNV envelope (E) protein is a highly antigenic protein that elicits the majority of virus-neutralizing antibodies during a WNV immune response. Leghorn chickens were given three vaccinations (each 2 wk apart) of E protein orally (20 ??g or 100 ??g/dose), of E protein intramuscularly (IM, 20 ??g/dose), or of adjuvant only (control group) followed by a WNV challenge. Viremias were measured post-WNV infection, and three new enzyme-linked immunosorbent assays were developed for quantifying IgM, IgY, and IgA-mediated immune response of birds following WNV infection. WNV viremia levels were significantly lower in the IM group than in both oral groups and the control group. Total WNV E protein-specific IgY production was significantly greater, and WNV nonstructural 1-specific IgY was significantly less, in the IM group compared to all other treatment groups. The results of this study indicate that IM vaccination of chickens with E protein is protective against WNV infection and results in a significantly different antibody production profile as compared to both orally vaccinated and nonvaccinated birds. ?? 2009 American Association of Avian Pathologists.

  14. The Israeli strain IS-98-ST1 of West Nile virus as viral model for West Nile encephalitis in the Old World

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    Lucas Marianne

    2004-11-01

    Full Text Available Abstract West Nile virus (WNV recently became a major public health concern in North America, the Middle East, and Europe. In contrast with the investigations of the North-American isolates, the neurovirulence properties of Middle-Eastern strains of WNV have not been extensively characterized. Israeli WNV strain IS-98-ST1 that has been isolated from a white stork in 1998, was found to be highly neuroinvasive in adult C57BL/6 mice. Strain IS-98-ST1 infects primary neuronal cells from mouse cortex, causing neuronal death. These results demonstrate that Israeli strain IS-98-ST1 provides a suitable viral model for WNV-induced disease associated with recent WNV outbreaks in the Old World.

  15. Recent circulation of West Nile virus and potentially other closely related flaviviruses in Southern France.

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    Vittecoq, Marion; Lecollinet, Sylvie; Jourdain, Elsa; Thomas, Frédéric; Blanchon, Thomas; Arnal, Audrey; Lowenski, Steeve; Gauthier-Clerc, Michel

    2013-08-01

    In recent years, the number of West Nile virus (WNV) cases reported in horses and humans has increased dramatically throughout the Mediterranean basin. Furthermore, the emergence of Usutu virus (USUV) in Austria in 2001, and its subsequent expansion to Hungary, Spain, Italy, Switzerland, the United Kingdom, and Germany, has given added cause for concern regarding the impact of the spread of flaviviruses on human and animal health in western Europe. Despite frequent detection of WNV and USUV cases in neighboring countries, no case of WNV has been detected in France since 2006 and USUV has never been reported. However, recent investigations focused on detecting the circulation of flaviviruses in France are lacking. We investigated the circulation of WNV and USUV viruses in wild birds in southern France on the basis of a serological survey conducted on a sentinel species, the magpie (Pica pica), in the Camargue area from November, 2009, to December, 2010. We detected WNV-neutralizing antibodies at a high titer (160) in a second-year bird showing recent exposure to WNV, although no WNV case has been detected in humans or in horses since 2004 in the Camargue. In addition, we observed low titers (10 or 20) of USUV-specific antibodies in six magpies, two of which were also seropositive for WNV. Such low titers do not give grounds for concluding that these birds had been exposed to USUV; cross-reactions at low titers may occur between antigenically closely related flaviviruses. But these results urge for further investigations into the circulation of flaviviruses in southern France. They also emphasize the necessity of undertaking epidemiological studies on a long-term basis, rather than over short periods following public health crises, to gain insight into viral dynamics within natural reservoirs. PMID:23930977

  16. Spatial and temporal distribution of West Nile virus in horses in Israel (1997-2013--from endemic to epidemics.

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    Karin Aharonson-Raz

    Full Text Available With the rapid global spread of West Nile virus (WNV and the endemic state it has acquired in new geographical areas, we hereby bring a thorough serological investigation of WNV in horses in a longstanding endemic region, such as Israel. This study evaluates the environmental and demographic risk factors for WNV infection in horses and suggests possible factors associated with the transition from endemic to epidemic state. West Nile virus seroprevalence in horses in Israel was determined throughout a period of more than a decade, before (1997 and after (2002 and 2013 the massive West Nile fever outbreak in humans and horses in 2000. An increase in seroprevalence was observed, from 39% (113/290 in 1997 to 66.1% (547/827 in 2002 and 85.5% (153/179 in 2013, with persistent significantly higher seroprevalence in horses situated along the Great Rift Valley (GRV area, the major birds' migration route in Israel. Demographic risk factors included age and breed of the horse. Significantly lower spring precipitation was observed during years with increased human incidence rate that occurred between 1997-2007. Hence, we suggest referring to Israel as two WNV distinct epidemiological regions; an endemic region along the birds' migration route (GRV and the rest of the country which perhaps suffers from cyclic epidemics. In addition, weather conditions, such as periods of spring drought, might be associated with the transition from endemic state to epidemic state of WNV.

  17. [L-Lysine-α-Oxidase in vitro Activity in Experiments on Models of Viruses Sindbis, Forest-Spring Encephalitis, Western Nile, Tyaginya and Dhori].

    Science.gov (United States)

    Smirnova, I P; Larichev, V F; Shneider, Yu A

    2015-01-01

    The antitumor effect of L-lysine-α-oxidase from the culture fluid of Trichoderma harzianum Rifai F-180 was investigated for the first time. The in vitro studies revealed its high activity on a model of the forest-spring encephalitis virus and no activity against the Sindbis, Western Nile, Tyaginya and Dhori viruses. PMID:26415376

  18. Occurrence of avian Plasmodium and West Nile virus in culex species in Wisconsin

    Science.gov (United States)

    Hughes, T.; Irwin, P.; Hofmeister, E.; Paskewitz, S.M.

    2010-01-01

    The occurrence of multiple pathogens in mosquitoes and birds could affect the dynamics of disease transmission. We collected adult Culex pipiens and Cx. restuans (Cx. pipiens/restuans hereafter) from sites in Wisconsin and tested them for West Nile virus (WNV) and for avian malaria (Plasmodium). Gravid Cx. pipiens/restuans were tested for WNV using a commercial immunoassay, the RAMP?? WNV test, and positive results were verified by reverse transcriptasepolymerase chain reaction. There were 2 WNV-positive pools of Cx. pipiens/restuans in 2006 and 1 in 2007. Using a bias-corrected maximum likelihood estimation, the WNV infection rate for Cx. pipiens/restuans was 5.48/1,000 mosquitoes in 2006 and 1.08/1,000 mosquitoes in 2007. Gravid Cx. pipiens or Cx. restuans were tested individually for avian Plasmodium by a restriction enzymebased assay. Twelve mosquitoes were positive for avian Plasmodium (10.0), 2 were positive for Haemoproteus, and 3 were positive for Leucocytozoon. There were 4 mixed infections, with mosquitoes positive for >1 of the hemosporidian parasites. This work documents a high rate of hemosporidian infection in Culex spp. and illustrates the potential for co-infections with other arboviruses in bird-feeding mosquitoes and their avian hosts. In addition, hemosporidian infection rates may be a useful tool for investigating the ecological dynamics of Culex/avian interactions. ?? 2010 by The American Mosquito Control Association, Inc.

  19. Importance of Wetlands Management for West Nile Virus Circulation Risk, Camargue, Southern France

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    Sophie Pradier

    2014-08-01

    Full Text Available To assess environmental and horse-level risk factors associated with West Nile Virus (WNV circulation in Camargue, Southern France, a serosurvey was conducted on non-vaccinated horses (n = 1159 from 134 stables in 2007 and 2008. Fifteen Landsat images were examined to quantify areas with open water and flooded vegetation around sampled horses. Mean percentages of areas of open water and flooded vegetation, as well as variations in these percentages between 3 periods (November to February = NOT, March to July = END and August to October = EPI, were calculated for buffers of 2 km radius around the stables. Results of the final logistic regression showed that the risk of WNV seropositivity in horses decreased with their date of acquisition and age. Results also demonstrated the significant role of environmental variables. Horse serological status was associated with variations of open water areas between the NOT (November to February and END (March to July periods, as well as between END and EPI (August to October. WNV spillover was found more intense in areas where water level decreased strongly from winter to spring and from spring to summer.

  20. Seasonal and habitat effects on dengue and West Nile virus vectors in San Juan, Puerto Rico.

    Science.gov (United States)

    Smith, Joshua; Amador, Manuel; Barrera, Roberto

    2009-03-01

    The presence of West Nile (WNV) and dengue viruses and the lack of recent mosquito surveys in Puerto Rico prompted an investigation on the distribution and abundance of potential arbovirus vectors in the San Juan Metropolitan Area, and their variation with seasons and habitats. We sampled mosquitoes in early and late 2005 in 58 sites from forests, nonforest vegetation, wetlands, and high- and low-density housing areas using ovijars, Centers for Disease Control and Prevention miniature light/CO2 traps, and gravid traps. A total of 28 mosquito species was found. San Juan had potential WNV enzooticvectors (Culex nigripalpus) within and around the city in wetlands and forests, but few were captured in residential areas. A potential WNV bridge vector (Cx. quinquefasciatus) was abundant in urbanized areas, and it was positively correlated with the main dengue vector, Aedes aegypti. High-density housing areas harbored more Ae. aegypti. Container mosquitoes, including Aedes mediovittatus, were more abundant during the climax of the rainy season when most dengue occurs in Puerto Rico. The greatest risk for contracting WNV would be visiting forests and swamps at night. Culex (Culex) and Culex (Melanoconion) mosquito species were more abundant during the transition dry-wet seasons (March-May). PMID:19432067

  1. Acute flaccid paralysis due to West nile virus infection in adults: A paradigm shift entity

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    Boby Varkey Maramattom

    2014-01-01

    Full Text Available Three cases of acute flaccid paralysis (AFP with preceding fever are described. One patient had a quadriparesis with a florid meningoencephalitic picture and the other two had asymmetric flaccid paralysis with fasciculations at the onset of illness. Magnetic resonance imaging in two cases showed prominent hyperintensitities in the spinal cord and brainstem with prominent involvement of the grey horn (polio-myelitis. Cerebrospinal fluid (CSF polymerase chain reaction was positive for West Nile virus (WNV in the index patient. All three cases had a positive WNV immunoglobulin M antibody in serum/CSF and significantly high titer of WNV neutralizing antibody in serum, clearly distinguishing the infection from other Flaviviridae such as Japanese encephalitis. WNV has been recognized in India for many decades; however, AFP has not been adequately described. WNV is a flavivirus that is spread by Culex mosquitoes while they take blood meals from humans and lineage 1 is capable of causing a devastating neuro-invasive disease with fatal consequences or severe morbidity. We describe the first three laboratory confirmed cases of WNV induced AFP from Kerala and briefly enumerate the salient features of this emerging threat.

  2. Evaluation of antibody response to vaccination against West Nile virus in thick billed parrots (Rhynchopsitta pachyrhyncha).

    Science.gov (United States)

    Glavis, Jennifer; Larsen, R Scott; Lamberski, Nadine; Gaffney, Patricia; Gardner, Ian

    2011-09-01

    West Nile virus (WNV) was first documented in North America in New York City in 1999. Several deaths attributable to WNV have been reported in captive thick-billed parrots (Rhynchopsitta pachyrhyncha), an endangered psittacine native to North America. The serologic responses in 12 captive adult thick-billed parrots after a series of three initial WNV vaccine injections with annual boosters over 6 yr was evaluated. In addition, the serologic responses of 11 thick-billed parrot chicks following an initial vaccination series to determine if there were seroconversions were also reported. Most adults (67%) had seroconverted after 5 yr of annual vaccination, with a median titer of 1:80 (range 1:40-1:160) for those that seroconverted. After the first year, birds were likely naturally exposed to WNV, which limited interpretation of titers. None of the chicks seroconverted during the initial three-vaccine series; only two of four chicks (50%) had seroconverted when tested at the 1-yr yearly booster, and at 2 yr, three of four chicks had seroconverted. Although some birds had detectable antibody titers, it is unclear whether this vaccine can reliably provide protection against WNV in thick-billed parrots.

  3. Land use patterns and the risk of West Nile virus transmission in central Illinois.

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    Gardner, Allison M; Lampman, Richard L; Muturi, Ephantus J

    2014-05-01

    Understanding how human land use patterns influence mosquito ecology and the risk of mosquito-borne pathogens is critical for the development of disease management strategies. We examined how different environments influenced mosquito species composition, abundance, and West Nile virus (WNV) infection rates in central Illinois. Using a combination of gravid traps and CDC light traps, adult mosquitoes were collected every other week from June 24 to September 16, 2012, in four major land use categories-row crops, prairies, forest fragments, and residential neighborhoods. The mosquitoes were identified to species morphologically, and pools of pure and mixed Culex mosquitoes (primarily Culex pipiens and Culex restuans) were tested for WNV-RNA by qRT-PCR. Mosquito species diversity was significantly higher in forest habitats compared to residential, agricultural, and prairie land use categories. All the four landscape types were equally important habitats for WNV vectors Cx. pipiens and Cx. restuans, contrary to previous findings that these species principally inhabit the residential areas. WNV-infected mosquito pools were observed in all land use types, and the infection rates overlapped among land use categories. Although our findings support the importance of residential habitats for WNV transmission to humans, they also establish that prairie, row crops, and wood lots are potentially important refuges for enzootic transmission. This is particularly important in urban ecosystems where these land use categories are small, interspersed fragments serving as potential refuge sites during periods of low rainfall. PMID:24746038

  4. Rab8b Regulates Transport of West Nile Virus Particles from Recycling Endosomes.

    Science.gov (United States)

    Kobayashi, Shintaro; Suzuki, Tadaki; Kawaguchi, Akira; Phongphaew, Wallaya; Yoshii, Kentaro; Iwano, Tomohiko; Harada, Akihiro; Kariwa, Hiroaki; Orba, Yasuko; Sawa, Hirofumi

    2016-03-18

    West Nile virus (WNV) particles assemble at and bud into the endoplasmic reticulum (ER) and are secreted from infected cells through the secretory pathway. However, the host factor related to these steps is not fully understood. Rab proteins, belonging to the Ras superfamily, play essential roles in regulating many aspects of vesicular trafficking. In this study, we sought to determine which Rab proteins are involved in intracellular trafficking of nascent WNV particles. RNAi analysis revealed that Rab8b plays a role in WNV particle release. We found that Rab8 and WNV antigen were colocalized in WNV-infected human neuroblastoma cells, and that WNV infection enhanced Rab8 expression in the cells. In addition, the amount of WNV particles in the supernatant of Rab8b-deficient cells was significantly decreased compared with that of wild-type cells. We also demonstrated that WNV particles accumulated in the recycling endosomes in WNV-infected cells. In summary, these results suggest that Rab8b is involved in trafficking of WNV particles from recycling endosomes to the plasma membrane. PMID:26817838

  5. West nile virus infection in the Mesopotamia region, Syria border of Turkey.

    Science.gov (United States)

    Karakoç, Zehra Çağla; Tüzüner, Bora Mete; Ergonul, Onder; Pierro, Anna; Di Fonzo, Eugenio; Koruk, İbrahim; Sambri, Vittorio

    2013-10-01

    We described the serological prevalence of West Nile Virus (WNV) antibodies among the human population in a historical and strategic region of Turkey. A serologic survey was conducted based on suspected cases in April, 2009, in the Mesopotamia region of Turkey, in the villages that were located alongside the Zergan River. All the sera were tested by enzyme-linked immunosorbent assay ELISA (Euroimmune™), and the positive samples were tested by immunofluorescent assay (IFA; Euroimmune™). As confirmation, neutralizing antibodies against WNV were tested by microneutralization assay (MNTA). In total, 307 individuals were included. The MNTA test was found to be positive among 52 individuals out of 307 (17%). In multivariate analysis, age >50 [odds ratio (OR)=5.2, confidence interval (CI) 2.76-9.97, p<0.001) and being in an occupational risk group (OR=2.02, CI 1.02-4.04, p=0.044) were found to be the risk factors for WNV seropositivity with the MNTA test. The physicians in the region should be aware of the risk of WNV infection and should be alerted to detect the clinical cases. PMID:23808974

  6. Experimental infection of cliff swallows (Petrochelidon pyrrhonota) with varying doses of West Nile virus

    Science.gov (United States)

    Oesterle, P.T.; Nemeth, N.M.; VanDalen, Kaci K.; Sullivan, H.; Bentler, K.T.; Young, G.R.; McLean, R.G.; Clark, L.; Smeraski, C.; Hall, J.S.

    2009-01-01

    Cliff swallows (Petrochelidon pyrrhonota) were inoculated with differing doses of West Nile virus (WNV) to evaluate their potential role as reservoir hosts in nature. Swallows often nest in large colonies in habitats and months associated with high mosquito abundance and early WNV transmission in North America. Additionally, cliff swallow diet consists of insects, including mosquitoes, leading to an additional potential route of WNV infection. The average peak viremia titer among infected cliff swallows was 106.3 plaque-forming units (PFU)/mL serum and the reservoir competence index was 0.34. There was no correlation between dose and probability of becoming infected or viremia peak and duration. Oral shedding was detected from 2 to 14 days post-inoculation with an average peak titer of 1044 PFU/swab. These results suggest that cliff swallows are competent reservoir hosts of WNV and therefore, they may play a role in early seasonal amplification and maintenance of WNV. Copyright ?? 2009 by The American Society of Tropical Medicine and Hygiene.

  7. Temperature, viral genetics, and the transmission of West Nile virus by Culex pipiens mosquitoes.

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    A Marm Kilpatrick

    2008-06-01

    Full Text Available The distribution and intensity of transmission of vector-borne pathogens can be strongly influenced by the competence of vectors. Vector competence, in turn, can be influenced by temperature and viral genetics. West Nile virus (WNV was introduced into the United States of America in 1999 and subsequently spread throughout much of the Americas. Previously, we have shown that a novel genotype of WNV, WN02, first detected in 2001, spread across the US and was more efficient than the introduced genotype, NY99, at infecting, disseminating, and being transmitted by Culex mosquitoes. In the current study, we determined the relationship between temperature and time since feeding on the probability of transmitting each genotype of WNV. We found that the advantage of the WN02 genotype increases with the product of time and temperature. Thus, warmer temperatures would have facilitated the invasion of the WN02 genotype. In addition, we found that transmission of WNV accelerated sharply with increasing temperature, T, (best fit by a function of T(4 showing that traditional degree-day models underestimate the impact of temperature on WNV transmission. This laboratory study suggests that both viral evolution and temperature help shape the distribution and intensity of transmission of WNV, and provides a model for predicting the impact of temperature and global warming on WNV transmission.

  8. Alterations in the Aedes aegypti transcriptome during infection with West Nile, dengue and yellow fever viruses.

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    Tonya M Colpitts

    2011-09-01

    Full Text Available West Nile (WNV, dengue (DENV and yellow fever (YFV viruses are (reemerging, mosquito-borne flaviviruses that cause human disease and mortality worldwide. Alterations in mosquito gene expression common and unique to individual flaviviral infections are poorly understood. Here, we present a microarray analysis of the Aedes aegypti transcriptome over time during infection with DENV, WNV or YFV. We identified 203 mosquito genes that were ≥ 5-fold differentially up-regulated (DUR and 202 genes that were ≥ 10-fold differentially down-regulated (DDR during infection with one of the three flaviviruses. Comparative analysis revealed that the expression profile of 20 DUR genes and 15 DDR genes was quite similar between the three flaviviruses on D1 of infection, indicating a potentially conserved transcriptomic signature of flaviviral infection. Bioinformatics analysis revealed changes in expression of genes from diverse cellular processes, including ion binding, transport, metabolic processes and peptidase activity. We also demonstrate that virally-regulated gene expression is tissue-specific. The overexpression of several virally down-regulated genes decreased WNV infection in mosquito cells and Aedes aegypti mosquitoes. Among these, a pupal cuticle protein was shown to bind WNV envelope protein, leading to inhibition of infection in vitro and the prevention of lethal WNV encephalitis in mice. This work provides an extensive list of targets for controlling flaviviral infection in mosquitoes that may also be used to develop broad preventative and therapeutic measures for multiple flaviviruses.

  9. Induction of epitope-specific neutralizing antibodies against West Nile virus.

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    Oliphant, Theodore; Nybakken, Grant E; Austin, S Kyle; Xu, Qing; Bramson, Jonathan; Loeb, Mark; Throsby, Mark; Fremont, Daved H; Pierson, Theodore C; Diamond, Michael S

    2007-11-01

    Previous studies have established that an epitope on the lateral ridge of domain III (DIII-lr) of West Nile virus (WNV) envelope (E) protein is recognized by strongly neutralizing type-specific antibodies. In contrast, an epitope against the fusion loop in domain II (DII-fl) is recognized by flavivirus cross-reactive antibodies with less neutralizing potential. Using gain- and loss-of-function E proteins and wild-type and variant WNV reporter virus particles, we evaluated the expression pattern and activity of antibodies against the DIII-lr and DII-fl epitopes in mouse and human serum after WNV infection. In mice, immunoglobulin M (IgM) antibodies to the DIII-lr epitope were detected at low levels at day 6 after infection. However, compared to IgG responses against other epitopes in DI and DII, which were readily detected at day 8, the development of IgG against DIII-lr epitope was delayed and did not appear consistently until day 15. This late time point is notable since almost all death after WNV infection in mice occurs by day 12. Nonetheless, at later time points, DIII-lr antibodies accumulated and comprised a significant fraction of the DIII-specific IgG response. In sera from infected humans, DIII-lr antibodies were detected at low levels and did not correlate with clinical outcome. In contrast, antibodies to the DII-fl were detected in all human serum samples and encompassed a significant percentage of the anti-E protein response. Our experiments suggest that the highly neutralizing DIII-lr IgG antibodies have little significant role in primary infection and that the antibody response of humans may be skewed toward the induction of cross-reactive, less-neutralizing antibodies.

  10. The Australian Public is Still Vulnerable to Emerging Virulent Strains of West Nile Virus

    Science.gov (United States)

    Prow, Natalie A.; Hewlett, Elise K.; Faddy, Helen M.; Coiacetto, Flaminia; Wang, Wenqi; Cox, Tarnya; Hall, Roy A.; Bielefeldt-Ohmann, Helle

    2014-01-01

    The mosquito-borne West Nile virus (WNV) is responsible for outbreaks of viral encephalitis in humans and horses with particularly virulent strains causing recent outbreaks in Eastern Europe, the Middle East, and North America. In Australia, a strain of WNV, Kunjin (WNVKUN), is endemic in the north and infection with this virus is generally asymptomatic. However, in early 2011, following extensive flooding, an unprecedented outbreak of WNVKUN encephalitis in horses occurred in South-Eastern Australia, resulting in more than 1,000 cases and a mortality of 10–15%. Despite widespread evidence of equine infections, there was only a single mild human case reported during this outbreak. To understand why clinical disease was seen in horses without similar observations in the human population, a serosurvey was conducted using blood donor samples from areas where equine cases were reported to assess level of flavivirus exposure. The seroprevalence to WNVKUN in humans was low before the outbreak (0.7%), and no significant increase was demonstrated after the outbreak period (0.6%). Due to unusual epidemiological features during this outbreak, a serosurvey was also conducted in rabbits, a potential reservoir host. Out of 675 animals, sampled across Australia between April 2011 and November 2012, 86 (12.7%) were seropositive for WNVKUN, with the highest prevalence during February of 2012 (28/145; 19.3%). As this is the first serological survey for WNVKUN in Australian feral rabbits, it remains to be determined whether wild rabbits are able to develop a high enough viremia to actively participate in WNV transmission in Australia. However, they may constitute a sentinel species for arbovirus activity, and this is the focus of on-going studies. Collectively, this study provides little evidence of human exposure to WNVKUN during the 2011 outbreak and indicates that the Australian population remains susceptible to the emergence of virulent strains of WNV. PMID:25279370

  11. The Australian public is still vulnerable to emerging virulent strains of West Nile virus

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    Natalie A. Prow

    2014-09-01

    Full Text Available The mosquito-borne West Nile virus (WNV is responsible for outbreaks of viral encephalitis in humans and horses with particularly virulent strains causing recent outbreaks in Eastern Europe, the Middle East and North America. In Australia, a strain of WNV, Kunjin (WNVKUN, is endemic in the north and infection with this virus is generally asymptomatic. However, in early 2011, following extensive flooding, an unprecedented outbreak of WNVKUN encephalitis in horses occurred in south-eastern Australia, resulting in more than 1,000 cases and a mortality of 10-15%. Despite widespread evidence of equine infections, there was only a single mild human case reported during this outbreak. To understand why clinical disease was seen in horses without similar observations in the human population, a serosurvey was conducted using blood donor samples from areas where equine cases were reported to assess level of flavivirus exposure. The seroprevalence to WNVKUN in humans was low before the outbreak (0.7%, and no significant increase was demonstrated after the outbreak period (0.6%. Due to unusual epidemiological features during this outbreak, a serosurvey was also conducted in rabbits, a potential reservoir host. Out of 675 animals, sampled across Australia between April 2011 and November 2012, 86 (12.7% were seropositive for WNVKUN, with the highest prevalence during February of 2012 (28/145; 19.3%. As this is the first serological survey for WNVKUN in Australian feral rabbits, it remains to be determined whether wild rabbits are able to develop a high enough viraemia to actively participate in WNV transmission in Australia. However, they may constitute a sentinel species for arbovirus activity, and this is the focus of ongoing studies. Collectively this study provides little evidence of human exposure to WNVKUN during the 2011 outbreak and indicates that the Australian population remains susceptible to the emergence of virulent strains of WNV.

  12. Immunodominant West Nile Virus T Cell Epitopes Are Fewer in Number and Fashionably Late.

    Science.gov (United States)

    Kaabinejadian, Saghar; McMurtrey, Curtis P; Kim, Sojung; Jain, Rinki; Bardet, Wilfried; Schafer, Fredda B; Davenport, Jason L; Martin, Aaron D; Diamond, Michael S; Weidanz, Jon A; Hansen, Ted H; Hildebrand, William H

    2016-05-15

    Class I HLA molecules mark infected cells for immune targeting by presenting pathogen-encoded peptides on the cell surface. Characterization of viral peptides unique to infected cells is important for understanding CD8(+) T cell responses and for the development of T cell-based immunotherapies. Having previously reported a series of West Nile virus (WNV) epitopes that are naturally presented by HLA-A*02:01, in this study we generated TCR mimic (TCRm) mAbs to three of these peptide/HLA complexes-the immunodominant SVG9 (E protein), the subdominant SLF9 (NS4B protein), and the immunorecessive YTM9 (NS3 protein)-and used these TCRm mAbs to stain WNV-infected cell lines and primary APCs. TCRm staining of WNV-infected cells demonstrated that the immunorecessive YTM9 appeared several hours earlier and at 5- to 10-fold greater density than the more immunogenic SLF9 and SVG9 ligands, respectively. Moreover, staining following inhibition of the TAP demonstrated that all three viral ligands were presented in a TAP-dependent manner despite originating from different cellular compartments. To our knowledge, this study represents the first use of TCRm mAbs to define the kinetics and magnitude of HLA presentation for a series of epitopes encoded by one virus, and the results depict a pattern whereby individual epitopes differ considerably in abundance and availability. The observations that immunodominant ligands can be found at lower levels and at later time points after infection suggest that a reevaluation of the factors that combine to shape T cell reactivity may be warranted.

  13. Immunodominant West Nile Virus T Cell Epitopes Are Fewer in Number and Fashionably Late.

    Science.gov (United States)

    Kaabinejadian, Saghar; McMurtrey, Curtis P; Kim, Sojung; Jain, Rinki; Bardet, Wilfried; Schafer, Fredda B; Davenport, Jason L; Martin, Aaron D; Diamond, Michael S; Weidanz, Jon A; Hansen, Ted H; Hildebrand, William H

    2016-05-15

    Class I HLA molecules mark infected cells for immune targeting by presenting pathogen-encoded peptides on the cell surface. Characterization of viral peptides unique to infected cells is important for understanding CD8(+) T cell responses and for the development of T cell-based immunotherapies. Having previously reported a series of West Nile virus (WNV) epitopes that are naturally presented by HLA-A*02:01, in this study we generated TCR mimic (TCRm) mAbs to three of these peptide/HLA complexes-the immunodominant SVG9 (E protein), the subdominant SLF9 (NS4B protein), and the immunorecessive YTM9 (NS3 protein)-and used these TCRm mAbs to stain WNV-infected cell lines and primary APCs. TCRm staining of WNV-infected cells demonstrated that the immunorecessive YTM9 appeared several hours earlier and at 5- to 10-fold greater density than the more immunogenic SLF9 and SVG9 ligands, respectively. Moreover, staining following inhibition of the TAP demonstrated that all three viral ligands were presented in a TAP-dependent manner despite originating from different cellular compartments. To our knowledge, this study represents the first use of TCRm mAbs to define the kinetics and magnitude of HLA presentation for a series of epitopes encoded by one virus, and the results depict a pattern whereby individual epitopes differ considerably in abundance and availability. The observations that immunodominant ligands can be found at lower levels and at later time points after infection suggest that a reevaluation of the factors that combine to shape T cell reactivity may be warranted. PMID:27183642

  14. The West Nile virus assembly process evades the conserved antiviral mechanism of the interferon-induced MxA protein

    Energy Technology Data Exchange (ETDEWEB)

    Hoenen, Antje [School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane (Australia); Gillespie, Leah [Department of Microbiology, La Trobe University, Melbourne (Australia); Department of Microbiology and Immunology, University of Melbourne, Melbourne (Australia); Morgan, Garry; Heide, Peter van der [Institute for Molecular Bioscience, University of Queensland, Brisbane (Australia); Khromykh, Alexander [School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane (Australia); Australian Infectious Diseases Research Centre, University of Queensland, Brisbane (Australia); Mackenzie, Jason, E-mail: jason.mackenzie@unimelb.edu.au [Department of Microbiology, La Trobe University, Melbourne (Australia); Department of Microbiology and Immunology, University of Melbourne, Melbourne (Australia)

    2014-01-05

    Flaviviruses have evolved means to evade host innate immune responses. Recent evidence suggests this is due to prevention of interferon production and signaling in flavivirus-infected cells. Here we show that the interferon-induced MxA protein can sequester the West Nile virus strain Kunjin virus (WNV{sub KUN}) capsid protein in cytoplasmic tubular structures in an expression-replication system. This sequestering resulted in reduced titers of secreted WNV{sub KUN} particles. We show by electron microscopy, tomography and 3D modeling that these cytoplasmic tubular structures form organized bundles. Additionally we show that recombinant ER-targeted MxA can restrict production of infectious WNV{sub KUN} under conditions of virus infection. Our results indicate a co-ordinated and compartmentalized WNV{sub KUN} assembly process may prevent recognition of viral components by MxA, particularly the capsid protein. This recognition can be exploited if MxA is targeted to intracellular sites of WNV{sub KUN} assembly. This results in further understanding of the mechanisms of flavivirus evasion from the immune system. - Highlights: • We show that the ISG MxA can recognize the West Nile virus capsid protein. • Interaction between WNV C protein and MxA induces cytoplasmic fibrils. • MxA can be retargeted to the ER to restrict WNV particle release. • WNV assembly process is a strategy to avoid MxA recognition.

  15. [Meningoencephalitis caused by West Nile virus in a renal transplant recipient].

    Science.gov (United States)

    Ertilav, Muhittin; Ozkul, Aykut; Zeytinoğlu, Ayşın; Sen, Sait; Sipahi, Savaş; Töz, Hüseyin; Kitiş, Omer; Eraslan, Cenk

    2014-10-01

    West Nile virus (WNV) infection which is asymptomatic or mild in normal population, it may cause serious clinical conditions leading to death in eldery and immunosupressed patients. The virus is mainly transmitted by mosquito bites, however transfusion, transplantation, transplasental and nosocomial ways have also been reported to be responsible for viral transmission. It is known that WNV may cause life-threatining conditions such as central nervous system (CNS) infections especially in bone marrow and solid organ transplant recipients. In this report, the first case of WNV encephalitis in an immunosuppressed patient with renal transplant in Turkey was presented. A 25-year-old male patient admitted to our hospital with the complaints of generalized myalgia, nausea and vomiting, after the 24. day of renal transplantation from a live donor. Since he developed diffuse tonic clonic seizures during his follow up, he was diagnosed as meningoencephalitis with the results of cranial magnetic resonance imaging (MR) and cerebrospinal fluid (CSF) biochemistry. Bacterial and fungal cultures of blood and CSF yielded negative results. CMV antigenemia test and CMV IgM in blood, and nucleic acid tests for CMV, EBV, HSV-1/2, VZV, HHV-6, enterovirus and parvovirus in CSF were also negative. However, WNV RNA was detected in CSF by an in-house reverse transcriptase (RT) nested PCR method. The sequence analysis (GenBank BLAST) of the virus showed that it had 99% similarity with Lineage-1 WNV strains. To define the transmission way of the virus to the recipient, WNV-RNA was searched in the renal biopsy sample and found negative by RT nested PCR. The clinical condition of the patient was improved with supportive therapy and by the de-escalation of immunosuppressive drugs [Mycophenolate mofetil (MMF; 1 g/day), cyclosporin (1 mg/kg/day)]. However WNV meningoencephalitis recurred one month later. The patient presented with fever, myalgia, confusions, leukocytosis, anemia, and repeating WNV

  16. Synergized resmethrin and corticosterone alter the chicken's response to west nile virus

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, Mark David [Los Alamos National Laboratory; Franson, J Christian [US GEOLOGICAL SURVEY; Mostl, Erich [UNIV OF VIENNA; Porter, Warren P [UNIV OF WISCONSIN; Hofmeister, Erik K [US GEOLOGICAL SURVEY

    2009-01-01

    Debate concerning arbovirus control strategies remains contentious because concern regarding the relative risk of viral infection and environmental toxicant exposure is high but inadequately characterized. Taking this into account, mosquito control agencies employ aerial insecticides only after arbovirus surveillance data indicate high local mosquito-infection-rates. Successfully mitigating the risk of adult-mosquito-control insecticides ('adulticides') to non-target species such as humans, domestic animals, fish, beneficial insects and wildlife, while increasing their efficacy to reduce arbovirus outbreak intensity requires targeted scientific data from animal toxicity studies and environmental monitoring activities. Wild birds are an important reservoir host for WNv and are potentially exposed to insecticides used for mosquito control. However, no risk assessments have evaluated whether insecticides augment or extend the potential transmissibility of West Nile virus (WNv) in birds. In order to augment existing resmethrin risk assessments, we aimed to determine whether synergized resmethrin (SR) may cause chickens to develop an elevated or extended WN viremia and if subacute stress may affect its immunotoxicity. We distributed 40 chickens into four groups then exposed them prior to and during WNv infection with SR (50 {mu}g/l resmethrin + 150 {mu}g/l piperonyl butoxide) and/or 20 mg/I corticosterone (CORT) in their drinking-water. Corticosterone was given for 10 continuous days and SR was given for 3 alternate days starting the 3rd day of CORT exposure, then chickens were subcutaneously inoculated with WNv on the 5th day of CORT treatment. Compared to controls, CORT treatment extended and elevated viremia, enhanced WNv-specific antibody and increased the percentage of birds that shed oral virus, whereas SR treatment extended viremia, depressed WNv-specific IgG, and increased the percentage of CORT-treated birds that shed oral virus. Corticosterone and SR

  17. Protection against West Nile virus infection in mice after inoculation with type I interferon-inducing RNA transcripts.

    Directory of Open Access Journals (Sweden)

    Miguel Rodríguez-Pulido

    Full Text Available West Nile virus (WNV is a neurovirulent single stranded RNA mosquito-borne flavivirus, whose main natural hosts are birds, but it also infects humans and horses. Nowadays, no human vaccine is commercially available and clinical treatment is only supportive. Recently, it has been shown that RNA transcripts, mimicking structural domains in the non-coding regions (NCRs of the foot-and mouth disease virus (FMDV induce a potent IFN response and antiviral activity in transfected cultured cells, and also reduced mice susceptibility to FMDV. By using different transcripts combinations, administration schedules, and infecting routes and doses, we have demonstrated that these FMDV RNA transcripts protect suckling and adult mice against lethal challenge with WNV. The protective activity induced by the transcripts was systemic and dependent on the infection route and dose. These results confirm the antiviral potential of these synthetic RNAs for fighting viruses of different families relevant for human and animal health.

  18. A recombinant West Nile virus envelope protein vaccine candidate produced in Spodoptera frugiperda expresSF+ cells

    OpenAIRE

    Bonafé, Nathalie; Rininger, Joseph A.; Chubet, Richard G.; Foellmer, Harald G.; Fader, Stacey; Anderson, John F.; Bushmich, Sandra L.; Anthony, Karen; Ledizet, Michel; Fikrig, Erol; Koski, Raymond A.; Kaplan, Paul

    2008-01-01

    In this study, a recombinant truncated West Nile virus envelope protein antigen (rWNV-E) was produced in serum-free cultures of the expresSF+ insect cell line via baculovirus infection. This production system was selected based on its use in the production of candidate human and animal vaccine antigens. A defined fermentation and purification process for the rWNV-E antigen was established to control for purity and immunogenicity of each protein batch. The material formulated with aluminum hyd...

  19. Sentinel birds in wild-bird resting sites as potential indicators for West Nile virus infections in Germany.

    Science.gov (United States)

    Ziegler, Ute; Seidowski, Diana; Globig, Anja; Fereidouni, Sasan R; Ulrich, Rainer G; Groschup, Martin H

    2010-06-01

    West Nile virus (WNV) is a mosquito-transmitted flavivirus with wild birds as its natural hosts. Ravens, falcons and jays are highly susceptible for WNV and develop deadly encephalitis, while other bird species undergo only subclinical infections. Migratory birds are efficient vectors for geographic spreading of WNV. Until now, WNV infections have not been diagnosed in Germany, but infections in humans and horses have occurred recently in Austria, Hungary and Italy. To investigate potential WNV introduction by infected wild birds, we have monitored the serological status of ducks in three national sentinel stations. No WNV-positive reactions were found, whereas sera from coots from northern Iran were positive.

  20. West Nile Virus: Using Adapted Primary Literature in Mathematical Biology to Teach Scientific and Mathematical Reasoning in High School

    Science.gov (United States)

    Norris, Stephen P.; Macnab, John S.; Wonham, Marjorie; de Vries, Gerda

    2009-05-01

    This paper promotes the use of adapted primary literature as a curriculum and instruction innovation for use in high school. Adapted primary literature is useful for promoting an understanding of scientific and mathematical reasoning and argument and for introducing modern science into the schools. We describe a prototype adapted from a published article on a mathematical model of the spread of the West Nile virus in North America. The prototype is available as a web-based resource that includes supplemental pedagogical units. Preliminary feedback from use of the prototype in two classrooms is described and a sketch of an ongoing formal evaluation is provided.

  1. Assessing Interventions to Manage West Nile Virus Using Multi-Criteria Decision Analysis with Risk Scenarios.

    Science.gov (United States)

    Hongoh, Valerie; Campagna, Céline; Panic, Mirna; Samuel, Onil; Gosselin, Pierre; Waaub, Jean-Philippe; Ravel, André; Samoura, Karim; Michel, Pascal

    2016-01-01

    The recent emergence of West Nile virus (WNV) in North America highlights vulnerability to climate sensitive diseases and stresses the importance of preventive efforts to reduce their public health impact. Effective prevention involves reducing environmental risk of exposure and increasing adoption of preventive behaviours, both of which depend on knowledge and acceptance of such measures. When making operational decisions about disease prevention and control, public health must take into account a wide range of operational, environmental, social and economic considerations in addition to intervention effectiveness. The current study aimed to identify, assess and rank possible risk reduction measures taking into account a broad set of criteria and perspectives applicable to the management of WNV in Quebec under increasing transmission risk scenarios, some of which may be related to ongoing warming in higher-latitude regions. A participatory approach was used to collect information on categories of concern to relevant stakeholders with respect to WNV prevention and control. Multi-criteria decision analysis was applied to examine stakeholder perspectives and their effect on strategy rankings under increasing transmission risk scenarios. Twenty-three preventive interventions were retained for evaluation using eighteen criteria identified by stakeholders. Combined evaluations revealed that, at an individual-level, inspecting window screen integrity, wearing light colored, long clothing, eliminating peridomestic larval sites and reducing outdoor activities at peak times were top interventions under six WNV transmission scenarios. At a regional-level, the use of larvicides was a preferred strategy in five out of six scenarios, while use of adulticides and dissemination of sterile male mosquitoes were found to be among the least favoured interventions in almost all scenarios. Our findings suggest that continued public health efforts aimed at reinforcing individual

  2. Experimental infection of Carrion crows (Corvus corone) with two European West Nile virus (WNV) strains.

    Science.gov (United States)

    Dridi, Maha; Vangeluwe, Didier; Lecollinet, Sylvie; van den Berg, Thierry; Lambrecht, Bénédicte

    2013-07-26

    West Nile virus (WNV) has become a wide-spread arbovirus in Europe and the Mediterranean Basin countries. This emerging zoonotic disease disseminated 13 years ago in North America where its impact on animal and public health has been considerable. Although American corvids have been the most reliable avian sentinels for WN surveillance in the United States, there is so far no data available about the susceptibility of their Western European counterparts to WNV. Clinical follow-up and serum, oral swabs and feathers viral RNA load monitoring was herein performed on wild-caught Carrion crows (Corvus corone) experimentally inoculated with two WNV strains, Is98 that was isolated from a stork in Israel where it elicited high rates of avian deaths in 1998, and Fr2000 which was only associated to sporadic equine cases in Camargue, France in 2000. Inoculated crows were sensitive to both WNV infections and, as expected from the available epidemiological data, Is98 induced a higher mortality rate (100% vs. 33%) and a quicker fatal outcome, with higher viral RNA loads detected in the serum, oral swabs and feathers than in the Fr2000 group. Therefore, Carrion crows should also be a target species for WNV surveillance in Western Europe, where reporting for abnormal mortalities could be completed by viral detection in the herein described avian matrices. These experimental findings also emphasize the peculiarity of the European situation where a large spectrum of WNV genetic and pathotypic variants have been so far isolated despite limited WN disease reports in wild birds. PMID:23434187

  3. Comparison of the Efficiency and Cost of West Nile Virus Surveillance Methods in California

    Science.gov (United States)

    Healy, Jessica M.; Reisen, William K.; Kramer, Vicki L.; Fischer, Marc; Lindsey, Nicole P.; Nasci, Roger S.; Macedo, Paula A.; White, Gregory; Takahashi, Richard; Khang, La

    2015-01-01

    Abstract Surveillance systems for West Nile virus (WNV) combine several methods to determine the location and timing of viral amplification. The value of each surveillance method must be measured against its efficiency and costs to optimize integrated vector management and suppress WNV transmission to the human population. Here we extend previous comparisons of WNV surveillance methods by equitably comparing the most common methods after standardization on the basis of spatial sampling density and costs, and by estimating optimal levels of sampling effort for mosquito traps and sentinel chicken flocks. In general, testing for evidence of viral RNA in mosquitoes and public-reported dead birds resulted in detection of WNV approximately 2–5 weeks earlier than serological monitoring of sentinel chickens at equal spatial sampling density. For a fixed cost, testing of dead birds reported by the public was found to be the most cost effective of the methods, yielding the highest number of positive results per $1000. Increased spatial density of mosquito trapping was associated with more precise estimates of WNV infection prevalence in mosquitoes. Our findings also suggested that the most common chicken flock size of 10 birds could be reduced to six to seven without substantial reductions in timeliness or sensitivity. We conclude that a surveillance system that uses the testing of dead birds reported by the public complemented by strategically timed mosquito and chicken sampling as agency resources allow would detect viral activity efficiently in terms of effort and costs, so long as susceptible bird species that experience a high mortality rate from infection with WNV, such as corvids, are present in the area. PMID:25700046

  4. Assessing Interventions to Manage West Nile Virus Using Multi-Criteria Decision Analysis with Risk Scenarios

    Science.gov (United States)

    Hongoh, Valerie; Campagna, Céline; Panic, Mirna; Samuel, Onil; Gosselin, Pierre; Waaub, Jean-Philippe; Ravel, André; Samoura, Karim; Michel, Pascal

    2016-01-01

    The recent emergence of West Nile virus (WNV) in North America highlights vulnerability to climate sensitive diseases and stresses the importance of preventive efforts to reduce their public health impact. Effective prevention involves reducing environmental risk of exposure and increasing adoption of preventive behaviours, both of which depend on knowledge and acceptance of such measures. When making operational decisions about disease prevention and control, public health must take into account a wide range of operational, environmental, social and economic considerations in addition to intervention effectiveness. The current study aimed to identify, assess and rank possible risk reduction measures taking into account a broad set of criteria and perspectives applicable to the management of WNV in Quebec under increasing transmission risk scenarios, some of which may be related to ongoing warming in higher-latitude regions. A participatory approach was used to collect information on categories of concern to relevant stakeholders with respect to WNV prevention and control. Multi-criteria decision analysis was applied to examine stakeholder perspectives and their effect on strategy rankings under increasing transmission risk scenarios. Twenty-three preventive interventions were retained for evaluation using eighteen criteria identified by stakeholders. Combined evaluations revealed that, at an individual-level, inspecting window screen integrity, wearing light colored, long clothing, eliminating peridomestic larval sites and reducing outdoor activities at peak times were top interventions under six WNV transmission scenarios. At a regional-level, the use of larvicides was a preferred strategy in five out of six scenarios, while use of adulticides and dissemination of sterile male mosquitoes were found to be among the least favoured interventions in almost all scenarios. Our findings suggest that continued public health efforts aimed at reinforcing individual

  5. Land cover, landscape structure, and West Nile virus circulation in southern France.

    Science.gov (United States)

    Pradier, S; Leblond, A; Durand, B

    2008-04-01

    The transmission of West Nile virus (WNV) is strongly influenced by environmental factors. In France, two endemic areas for WNV have been identified: Camargue and Var. The objective of our study was to test whether landscape characteristics could be associated with the risk of endemic circulation of WNV in these two ecologically different areas. Equine serological data collected during outbreaks in Var (2003) and Camargue (2004) were used. Both areas were marked out in cells of 5 km(2), and data were aggregated for each cell. Sixteen cells, classified as "high" level viral circulation, and 28 cells, classified as "low" level viral circulation were used for the analysis. The Corine Land Cover database (European Environment Agency) was used to evaluate, for each geographic cell, the area covered by 12 land cover classes, as well as the value of 5 landscape metrics (patch richness and density, edge density, the Shannon's diversity index, and interspersion and juxtaposition index (IJI). Multivariate linear generalized regression showed that IJI as well as the surface covered by heterogeneous agricultural areas were significantly higher in high level WNV circulation cells than in low level ones (p = 0.01 and 0.05 respectively). Both variables are indicators of a complex spatial biotope configuration that may favor the co-existence of competent vectors and reservoir hosts: the structure of the landscape thus appeared as a key element in WNV circulation. An internal validation was performed and the model was used to compute a risk map for the French Mediterranean coast. Cells with a probability > 0.8 of having a high level of viral circulation were found near Aix-en-Provence, Beziers, and Perpignan, areas where no serological study has yet been conducted. Equine cases reported in 2006 were all located in the neighborhood of cells having a > 0.8 probability for high WNV circulation status. PMID:18429693

  6. Serological, molecular and entomological surveillance demonstrates widespread circulation of West Nile virus in Turkey.

    Science.gov (United States)

    Ergunay, Koray; Gunay, Filiz; Erisoz Kasap, Ozge; Oter, Kerem; Gargari, Sepandar; Karaoglu, Taner; Tezcan, Seda; Cabalar, Mehmet; Yildirim, Yakup; Emekdas, Gürol; Alten, Bulent; Ozkul, Aykut

    2014-07-01

    West Nile virus (WNV), a mosquito-borne flavivirus with significant impact on human and animal health, has recently demonstrated an expanded zone of activity globally. The aim of this study is to investigate the frequency and distribution of WNV infections in potential vectors and several mammal and avian species in Turkey, where previous data indicate viral circulation. The study was conducted in 15 provinces across Turkey during 2011-2013. In addition, the entomological study was extended to 4 districts of the Turkish Republic of Northern Cyprus. WNV exposure was determined in humans, horses, sheep and ducks from Mersin, Sanliurfa, Van and Kars provinces of Turkey, via the detection of neutralizing antibodies. WNV RNA was sought in human and equine samples from Mersin, Adana and Mugla provinces. Field-collected mosquitoes from 92 sites at 46 locations were characterized morphologically and evaluated for viral RNA. Neutralizing antibodies were identified in 10.5% of the 1180 samples studied and detected in all species evaluated. Viral nucleic acids were observed in 5.9% of 522 samples but only in horses. A total of 2642 mosquito specimens belonging to 15 species were captured, where Ochlerotatus caspius (52.4%), Culex pipiens sensu lato (24.2%) comprise the most frequent species. WNV RNA was detected in 4 mosquito pools (1.9%), that comprise Oc. caspius Cx. pipiens s.l. and DNA barcoding revealed the presence of Cx. quinquefasciatus and Cx. perexiguus mosquitoes in infected Culex pools. All WNV partial sequences were characterized as lineage 1 clade 1a. These findings indicate a widespread WNV activity in Turkey, in Eastern Thrace and Mediterranean-Aegean regions as well as Southeastern and Northeastern Anatolia.

  7. Identification of class I HLA T cell control epitopes for West Nile virus.

    Directory of Open Access Journals (Sweden)

    Saghar Kaabinejadian

    Full Text Available The recent West Nile virus (WNV outbreak in the United States underscores the importance of understanding human immune responses to this pathogen. Via the presentation of viral peptide ligands at the cell surface, class I HLA mediate the T cell recognition and killing of WNV infected cells. At this time, there are two key unknowns in regards to understanding protective T cell immunity: 1 the number of viral ligands presented by the HLA of infected cells, and 2 the distribution of T cell responses to these available HLA/viral complexes. Here, comparative mass spectroscopy was applied to determine the number of WNV peptides presented by the HLA-A*11:01 of infected cells after which T cell responses to these HLA/WNV complexes were assessed. Six viral peptides derived from capsid, NS3, NS4b, and NS5 were presented. When T cells from infected individuals were tested for reactivity to these six viral ligands, polyfunctional T cells were focused on the GTL9 WNV capsid peptide, ligands from NS3, NS4b, and NS5 were less immunogenic, and two ligands were largely inert, demonstrating that class I HLA reduce the WNV polyprotein to a handful of immune targets and that polyfunctional T cells recognize infections by zeroing in on particular HLA/WNV epitopes. Such dominant HLA/peptide epitopes are poised to drive the development of WNV vaccines that elicit protective T cells as well as providing key antigens for immunoassays that establish correlates of viral immunity.

  8. A Hierarchical Approach Embedding Hydrologic and Population Modeling for a West Nile Virus Vector Prediction

    Science.gov (United States)

    Jian, Y.; Silvestri, S.; Marani, M.; Saltarin, A.; Chillemi, G.

    2012-12-01

    We applied a hierarchical state space model to predict the abundance of Cx.pipiens (a West Nile Virus vector) in the Po River Delta Region, Northeastern Italy. The study area has large mosquito abundance, due to a favorable environment and climate as well as dense human population. Mosquito data were collected on a weekly basis at more than 20 sites from May to September in 2010 and 2011. Cx.pipiens was the dominant species in our samples, accounting for about 90% of the more than 300,000 total captures. The hydrological component of the model accounted for evapotranspiration, infiltration and deep percolation to infer, in a 0D context, the local dynamics of soil moisture as a direct exogenous forcing of mosquito dynamics. The population model had a Gompertz structure, which included exogenous meteorological forcings and delayed internal dynamics. The models were coupled within a hierarchical statistical structure to overcome the relatively short length of the samples by exploiting the large number of concurrent observations available. The results indicated that Cx.pipiens abundance had significant density dependence at 1 week lag, which approximately matched its development time from larvae to adult. Among the exogenous controls, temperature, daylight hours, and soil moisture explained most of the dynamics. Longer daylight hours and lower soil moisture values resulted in higher abundance. The negative correlation of soil moisture and mosquito population can be explained with the abundance of water in the region (e.g. due to irrigation) and the preference for eutrophic habitats by Cx.pipien. Variations among sites were explained by land use factors as represented by distance to the nearest rice field and NDVI values: the carrying capacity decreased with increased distance to the nearest rice filed, while the maximum growth rate was positively related with NDVI. The model shows a satisfactory performance in predicting (potentially one week in advance) mosquito

  9. Spatio-temporal patterns of distribution of West Nile virus vectors in eastern Piedmont Region, Italy

    Directory of Open Access Journals (Sweden)

    Bisanzio Donal

    2011-12-01

    Full Text Available Abstract Background West Nile Virus (WNV transmission in Italy was first reported in 1998 as an equine outbreak near the swamps of Padule di Fucecchio, Tuscany. No other cases were identified during the following decade until 2008, when horse and human outbreaks were reported in Emilia Romagna, North Italy. Since then, WNV outbreaks have occurred annually, spreading from their initial northern foci throughout the country. Following the outbreak in 1998 the Italian public health authority defined a surveillance plan to detect WNV circulation in birds, horses and mosquitoes. By applying spatial statistical analysis (spatial point pattern analysis and models (Bayesian GLMM models to a longitudinal dataset on the abundance of the three putative WNV vectors [Ochlerotatus caspius (Pallas 1771, Culex pipiens (Linnaeus 1758 and Culex modestus (Ficalbi 1890] in eastern Piedmont, we quantified their abundance and distribution in space and time and generated prediction maps outlining the areas with the highest vector productivity and potential for WNV introduction and amplification. Results The highest abundance and significant spatial clusters of Oc. caspius and Cx. modestus were in proximity to rice fields, and for Cx. pipiens, in proximity to highly populated urban areas. The GLMM model showed the importance of weather conditions and environmental factors in predicting mosquito abundance. Distance from the preferential breeding sites and elevation were negatively associated with the number of collected mosquitoes. The Normalized Difference Vegetation Index (NDVI was positively correlated with mosquito abundance in rice fields (Oc. caspius and Cx. modestus. Based on the best models, we developed prediction maps for the year 2010 outlining the areas where high abundance of vectors could favour the introduction and amplification of WNV. Conclusions Our findings provide useful information for surveillance activities aiming to identify locations where the

  10. Integrated Human Surveillance Systems of West Nile Virus Infections in Italy: The 2012 Experience

    Directory of Open Access Journals (Sweden)

    Christian Napoli

    2013-12-01

    Full Text Available In Italy, a West Nile virus (WNV surveillance plan was firstly implemented in 2008 and 2009 in two affected regions and, since 2010, according to a national plan, a WNV neuroinvasive disease (WNND surveillance has to be carried out each year during the period 15 June–30 November, in those regions where WNV circulation has been demonstrated among humans, animals or vectors. Moreover, since WNV can be transmitted to humans even by blood transfusions and organ transplants obtained from infected donors, the national surveillance integrates the blood transfusions and organs transplant surveillances too. The paper describes the results of this integrated human surveillance in Italy in 2012. Overall, in 2012, 28 autochthonous confirmed cases of WNND were reported, 14 blood donations were found WNV positive by Nucleic Acid Amplification Test and no solid organ donors tested positive for WNV. Moreover, 17 cases of WNV fever were confirmed in Veneto region. When comparing the number of WNND cases reported to the surveillance system in previous 4 years (43 cases during the period 2008–2011, with those reported in 2012 an important increase was observed in 2012. The geographic distribution of human cases was consistent with the WNV circulation among animals and vectors. Moreover, the implementation of preventive measures for WNV transmission through blood components allowed the detection of blood donors positive for WNV, avoiding the further spread of the disease. Since surveillance strategies and preventive measures are based on the integration among human, animal and vector control activities, the Italian experience could be considered a good example of collaboration among different sectors of public health in a “one health” perspective.

  11. Assessing Interventions to Manage West Nile Virus Using Multi-Criteria Decision Analysis with Risk Scenarios.

    Science.gov (United States)

    Hongoh, Valerie; Campagna, Céline; Panic, Mirna; Samuel, Onil; Gosselin, Pierre; Waaub, Jean-Philippe; Ravel, André; Samoura, Karim; Michel, Pascal

    2016-01-01

    The recent emergence of West Nile virus (WNV) in North America highlights vulnerability to climate sensitive diseases and stresses the importance of preventive efforts to reduce their public health impact. Effective prevention involves reducing environmental risk of exposure and increasing adoption of preventive behaviours, both of which depend on knowledge and acceptance of such measures. When making operational decisions about disease prevention and control, public health must take into account a wide range of operational, environmental, social and economic considerations in addition to intervention effectiveness. The current study aimed to identify, assess and rank possible risk reduction measures taking into account a broad set of criteria and perspectives applicable to the management of WNV in Quebec under increasing transmission risk scenarios, some of which may be related to ongoing warming in higher-latitude regions. A participatory approach was used to collect information on categories of concern to relevant stakeholders with respect to WNV prevention and control. Multi-criteria decision analysis was applied to examine stakeholder perspectives and their effect on strategy rankings under increasing transmission risk scenarios. Twenty-three preventive interventions were retained for evaluation using eighteen criteria identified by stakeholders. Combined evaluations revealed that, at an individual-level, inspecting window screen integrity, wearing light colored, long clothing, eliminating peridomestic larval sites and reducing outdoor activities at peak times were top interventions under six WNV transmission scenarios. At a regional-level, the use of larvicides was a preferred strategy in five out of six scenarios, while use of adulticides and dissemination of sterile male mosquitoes were found to be among the least favoured interventions in almost all scenarios. Our findings suggest that continued public health efforts aimed at reinforcing individual

  12. Immunogenicity and protective efficacy of a recombinant subunit West Nile virus vaccine in rhesus monkeys.

    Science.gov (United States)

    Lieberman, Michael M; Nerurkar, Vivek R; Luo, Haiyan; Cropp, Bruce; Carrion, Ricardo; de la Garza, Melissa; Coller, Beth-Ann; Clements, David; Ogata, Steven; Wong, Teri; Martyak, Tim; Weeks-Levy, Carolyn

    2009-09-01

    The immunogenicity and protective efficacy of a recombinant subunit West Nile virus (WNV) vaccine was evaluated in rhesus macaques (Macaca mulatta). The vaccine consisted of a recombinant envelope (E) protein truncated at the C-terminal end, resulting in a polypeptide containing 80% of the N-terminal amino acids of the native WNV protein (WN-80E), mixed with an adjuvant (GPI-0100). WN-80E was produced in a Drosophila melanogaster expression system with high yield and purified by immunoaffinity chromatography using a monoclonal antibody specific for flavivirus E proteins. Groups of monkeys were vaccinated with formulations containing 1 or 25 microg of WN-80E antigen, and both humoral and cellular immunity were assessed after vaccination. The results demonstrated potent antibody responses to vaccination, as determined by both enzyme-linked immunosorbent assay and virus-neutralizing antibody assays. All vaccinated animals responded favorably, and there was little difference in response between animals immunized with 1 or 25 microg of WN-80E. Cellular immunity was determined by lymphocyte proliferation and cytokine production assays using peripheral blood mononuclear cells from vaccinated animals stimulated in vitro with WN-80E. Cell-mediated immune responses varied from animal to animal within each group. About half of the animals responded with lymphoproliferation, cytokine production, or both. Again, there was little difference in response between animals immunized with a 1- or 25-microg dose of WN-80E in the vaccine formulations. In a separate experiment, groups of monkeys were immunized with the WN-80E/GPI-0100 vaccine or an adjuvant-only control formulation. Animals were then challenged by inoculation of wild-type WNV, and the level of viremia in each animal was monitored daily for 10 days. The results showed that whereas all animals in the control group had detectable viremia for at least 3 days after challenge, all of the vaccinated animals were negative on all

  13. Serological evidence of widespread circulation of West Nile virus and other flaviviruses in equines of the Pantanal, Brazil.

    Science.gov (United States)

    Pauvolid-Corrêa, Alex; Campos, Zilca; Juliano, Raquel; Velez, Jason; Nogueira, Rita Maria Ribeiro; Komar, Nicholas

    2014-02-01

    A recent study reported neutralizing antibodies to West Nile virus (WNV) in horses from four ranches of southern Pantanal. To extend that study, a serosurvey for WNV and 11 Brazilian flaviviruses was conducted with 760 equines, 238 sheep and 61 caimans from 17 local cattle ranches. Among the tested equines, 32 were collected from a ranch where a neurologic disorder outbreak had been recently reported. The sera were initially screened by using a blocking ELISA and then titrated by 90% plaque-reduction neutralization test (PRNT90) for 12 flaviviruses. Employing the criterion of 4-fold greater titer, 78 (10.3%) equines were seropositive for Ilheus virus, 59 (7.8%) for Saint Louis encephalitis virus, 24 (3.2%) for WNV, two (0.3%) for Cacipacore virus and one (0.1%) for Rocio virus. No serological evidence was found linking the neurological disease that affected local equines to WNV. All caimans and sheep were negative by blocking ELISA for flaviviruses. There were no seropositive equines for Bussuquara, Iguape, Yellow fever and all four Dengue virus serotypes. The detection of WNV-seropositive equines in ten ranches and ILHV and SLEV-seropositive equines in fourteen ranches of two different sub-regions of Pantanal is strong evidence of widespread circulation of these flaviviruses in the region.

  14. Estimating the economic impact of a possible equine and human epidemic of West Nile virus infection in Belgium.

    Science.gov (United States)

    Humblet, Marie-France; Vandeputte, Sébastien; Fecher-Bourgeois, Fabienne; Léonard, Philippe; Gosset, Christiane; Balenghien, Thomas; Durand, Benoît; Saegerman, Claude

    2016-08-01

    This study aimed at estimating, in a prospective scenario, the potential economic impact of a possible epidemic of WNV infection in Belgium, based on 2012 values for the equine and human health sectors, in order to increase preparedness and help decision-makers. Modelling of risk areas, based on the habitat suitable for Culex pipiens, the main vector of the virus, allowed us to determine equine and human populations at risk. Characteristics of the different clinical forms of the disease based on past epidemics in Europe allowed morbidity among horses and humans to be estimated. The main costs for the equine sector were vaccination and replacement value of dead or euthanised horses. The choice of the vaccination strategy would have important consequences in terms of cost. Vaccination of the country's whole population of horses, based on a worst-case scenario, would cost more than EUR 30 million; for areas at risk, the cost would be around EUR 16-17 million. Regarding the impact on human health, short-term costs and socio-economic losses were estimated for patients who developed the neuroinvasive form of the disease, as no vaccine is available yet for humans. Hospital charges of around EUR 3,600 for a case of West Nile neuroinvasive disease and EUR 4,500 for a case of acute flaccid paralysis would be the major financial consequence of an epidemic of West Nile virus infection in humans in Belgium. PMID:27526394

  15. An Updated Checklist of the Mosquitoes of Oklahoma Including New State Records and West Nile Virus Vectors, 2003-06.

    Science.gov (United States)

    Noden, Bruce H; Coburn, Lisa; Wright, Russell; Bradley, Kristy

    2015-12-01

    The mosquito fauna of Oklahoma has not been evaluated since 1965 and no report has been published concerning species associated with urban areas in the state. Mosquito collections were conducted as part of the West Nile virus (WNV) surveillance program between April and November from 2003 to 2006, using standard collection methods. A total of 74,756 adults were collected in 26 urban centers in 16 counties of Oklahoma. Altogether, 40 species were recorded during this study period, bringing the total mosquito species recorded in Oklahoma to 62 species in 9 different genera and 18 subgenera. An updated checklist of Oklahoma mosquito fauna is included with a comparison to historical records. New state records include 3 species: Aedes muelleri, Anopheles perplexens, and Culex coronator. In addition to updating the checklist, 12 species of mosquitoes were tested for WNV. Pools of Culex pipiens complex represented the highest proportion testing positive for WNV (134/766, 17.5%), followed by Cx. tarsalis (13/192, 6.8%) and Aedes albopictus (5/215, 2.3%). West Nile virus-positive mosquitoes were detected earliest in June 2005 and latest in November 2004. Infected Cx. pipiens complex testing positive for WNV were more prevalent in the eastern and central areas of Oklahoma, whereas positive Cx. tarsalis were found mainly in the western areas of the state. This distinct geographical difference needs to be monitored and followed up to ensure optimal mosquito control efforts in Oklahoma communities with mosquito control capabilities.

  16. Effects of larval rearing temperature on immature development and West Nile virus vector competence of Culex tarsalis

    Directory of Open Access Journals (Sweden)

    Dodson Brittany L

    2012-09-01

    Full Text Available Abstract Background Temperature is known to induce changes in mosquito physiology, development, ecology, and in some species, vector competence for arboviruses. Since colonized mosquitoes are reared under laboratory conditions that can be significantly different from their field counterparts, laboratory vector competence experiments may not accurately reflect natural vector-virus interactions. Methods We evaluated the effects of larval rearing temperature on immature development parameters and vector competence of two Culex tarsalis strains for West Nile virus (WNV. Results Rearing temperature had a significant effect on mosquito developmental parameters, including shorter time to pupation and emergence and smaller female body size as temperature increased. However, infection, dissemination, and transmission rates for WNV at 5, 7, and 14 days post infectious feeding were not consistently affected. Conclusions These results suggest that varying constant larval rearing temperature does not significantly affect laboratory estimates of vector competence for WNV in Culex tarsalis mosquitoes.

  17. Identification of CD8(+) T Cell Epitopes in the West Nile Virus Polyprotein by Reverse-Immunology Using NetCTL

    DEFF Research Database (Denmark)

    Larsen, Mette Voldby; Lelic, A.; Parsons, R.;

    2010-01-01

    Background: West Nile virus (WNV) is a growing threat to public health and a greater understanding of the immune response raised against WNV is important for the development of prophylactic and therapeutic strategies. Methodology/Principal Findings: In a reverse-immunology approach, we used...

  18. Outdoor Hazards & Preventive Measures: West Nile Virus: A Clinical Commentary for the Camp Health Care Community; Poison Ivy: A Primer for Prevention; Lyme Disease Prevention and Control.

    Science.gov (United States)

    Reynolds, Ellen; Bauer, Holly; Ratner-Connolly, Heidi

    2003-01-01

    Transmitted by mosquitos, West Nile virus may cause serious illness, but the actual likelihood of infection is low. Prevention, implications, and recommendations for camps are discussed. Poison ivy identification, treatment, and complications are presented; a prevention quiz is included. Signs and symptoms of Lyme disease are described, as are…

  19. Serum Neutralization Assay Can Efficiently Replace Plaque Reduction Neutralization Test for Detection and Quantitation of West Nile Virus Antibodies in Human and Animal Serum Samples

    Science.gov (United States)

    Di Gennaro, Annapia; Casaccia, Claudia; Conte, Annamaria; Monaco, Federica; Savini, Giovanni

    2014-01-01

    A serum neutralization assay (SN) was compared with the official plaque reduction neutralization test for the quantitation of West Nile virus antibodies. A total of 1,348 samples from equid sera and 38 from human sera were tested by these two methods. Statistically significant differences were not observed, thus supporting the use of SN for routine purposes. PMID:25100824

  20. The effect of West Nile virus perceptions and knowledge on protective behavior and mosquito breeding in residential yards in Upstate New York

    NARCIS (Netherlands)

    Tuiten, W.; Koenraadt, C.J.M.; McComas, K.; Harrington, L.C.

    2009-01-01

    A knowledge, attitudes, and practices (KAP) questionnaire combined with entomological surveys of residential mosquito-breeding sites were conducted in two Upstate New York neighborhoods. We tested the hypothesis that “correct” West Nile virus (WNV) knowledge and perceptions correspond with the use o

  1. Culex pipiens, an experimental efficient vector of West Nile and Rift Valley fever viruses in the Maghreb region.

    Directory of Open Access Journals (Sweden)

    Fadila Amraoui

    Full Text Available West Nile fever (WNF and Rift Valley fever (RVF are emerging diseases causing epidemics outside their natural range of distribution. West Nile virus (WNV circulates widely and harmlessly in the old world among birds as amplifying hosts, and horses and humans as accidental dead-end hosts. Rift Valley fever virus (RVFV re-emerges periodically in Africa causing massive outbreaks. In the Maghreb, eco-climatic and entomologic conditions are favourable for WNV and RVFV emergence. Both viruses are transmitted by mosquitoes belonging to the Culex pipiens complex. We evaluated the ability of different populations of Cx. pipiens from North Africa to transmit WNV and the avirulent RVFV Clone 13 strain. Mosquitoes collected in Algeria, Morocco, and Tunisia during the summer 2010 were experimentally infected with WNV and RVFV Clone 13 strain at titers of 10(7.8 and 10(8.5 plaque forming units/mL, respectively. Disseminated infection and transmission rates were estimated 14-21 days following the exposure to the infectious blood-meal. We show that 14 days after exposure to WNV, all mosquito st developed a high disseminated infection and were able to excrete infectious saliva. However, only 69.2% of mosquito strains developed a disseminated infection with RVFV Clone 13 strain, and among them, 77.8% were able to deliver virus through saliva. Thus, Cx. pipiens from the Maghreb are efficient experimental vectors to transmit WNV and to a lesser extent, RVFV Clone 13 strain. The epidemiologic importance of our findings should be considered in the light of other parameters related to mosquito ecology and biology.

  2. Anticuerpos frente a virus West nile y otros virus transmitidos por artropodos en la poblacion del Delta del Ebro

    Directory of Open Access Journals (Sweden)

    Lozano Alvaro

    1998-01-01

    Full Text Available FUNDAMENTOS: El virus West Nile (VWN es un Flavivirus que se transmite al hombre a través de distintas especies de mosquitos y produce brotes y casos esporádicos de enfermedad en distintas regiones del Viejo Mundo, incluída la Cuenca Mediterránea. Las zonas húmedas europeas que acogen aves migratorias procedentes de África constituyen áreas de alto riesgo para esta infección, así como para otras infecciones víricas transmitidas por artrópodos. MÉTODOS: Con objeto de investigar la prevalencia de la infección por el VWN y otros virus de transmisión similar en la población humana del Delta del Ebro, se estudiaron 1037 muestras de suero, obtenidas en 10 localidades de la zona, para presencia de anticuerpos frente a VWN y otros 12 virus transmitidos por artrópodos (3 Alfavirus, 8 Flaviviridae y 1 Bunyaviridae mediante titulación por inhibición de la hemaglutinación (IHA. En algunos casos se estudió la presencia de IgM específica por IHA tras fraccionar el suero por centrifugación en gradientes de sacarosa. RESULTADOS: En total, se encontró reactividad significativa frente a alguno de los virus probados en 130 casos (12.5%; 4.1% frente a Alfavirus, 8.0% frente a Flaviviridae y 0.4% frente a Bunyaviridae. El análisis de los títulos de anticuerpos reveló porcentajes significativos de muestras con títulos elevados frente a antígenos de VWN y otros. La distribución de la seroprevalencia fue muy desigual, concentrándose fundamentalmente en 3 localidades del interior del Delta (Ampolla, San Jaime y Montells, donde la prevalencia de anticuerpos frente a Flaviviridae llegó a alcanzar el 30% y se observaron niveles residuales de IgM frente a VWN en algunos sueros. CONCLUSIONES: Estos resultados y los obtenidos previamente en otras regiones de la Península Ibérica sugieren que el VWN circula en la población humana de las zonas de riesgo y produce brotes epidémicos periódicos. Habida cuenta del alto porcentaje de

  3. Effect of environmental temperature on the ability of Culex pipiens (Diptera: Culicidae) to transmit West Nile virus.

    Science.gov (United States)

    Dohm, David J; O'Guinn, Monica L; Turell, Michael J

    2002-01-01

    Environmental temperature can affect the ability of mosquitoes to transmit an arbovirus. However, results of various studies indicate that these effects are not consistent among viruses or mosquito species, and there is no information available on the effect of environmental temperature on the ability of North American mosquito species to transmit West Nile (WN) virus. We evaluated the effect of incubation temperature (18, 20, 26, or 30 degrees C) on the ability of Culex pipiens L. derived from specimens collected during the outbreak in New York in 1999 to transmit a strain of WN virus obtained from a crow that died during this outbreak. Although mosquitoes fed on the same viremic chickens, infection rates were directly related to subsequent incubation temperatures. In mosquitoes held at 30 degrees C, virus was recovered from nearly all mosquitoes tested, disseminated infections were detected as early as 4 d after the infectious blood meal, and >90% of all mosquitoes had a disseminated infection 12 or more days after the infectious blood meal. In contrast, for mosquitoes held at 18 degrees C, disseminated infections were not detected until 25 d after the infectious blood meal, and even after 28 d, <30% contained a disseminated infection. Results for mosquitoes held at 20 and 26 degrees C were intermediate for both infection and dissemination rates. The effect of environmental temperature should to be considered when evaluating the vector competence of these mosquitoes and modeling risk of WN virus transmission in nature.

  4. Mosquito vectors of West Nile virus during an epizootic outbreak in Puerto Rico.

    Science.gov (United States)

    Barrera, R; MacKay, A; Amador, M; Vasquez, J; Smith, J; Díaz, A; Acevedo, V; Cabán, B; Hunsperger, E A; Muñoz-Jordán, J L

    2010-11-01

    The purpose of this investigation was to identify the mosquito (Diptera: Culicidae) vectors of West Nile virus (WNV; family Flaviviridae, genus Flavivirus) during an epizootic WNV outbreak in eastern Puerto Rico in 2007. In June 2006, 12 sentinel chicken pens with five chickens per pen were deployed in six types of habitats: herbaceous wetlands, mangrove forests, deciduous forests, evergreen forests, rural areas, and urban areas. Once WNV seroconversion in chickens was detected in June 2007, we began trapping mosquitoes using Centers for Disease Control and Prevention (CDC) miniature (light/CO2-baited) traps, CMT-20 collapsible mosquito (CO2- and ISCA SkinLure-baited) traps, and CDC gravid (hay infusion-baited) traps. We placed the CDC miniature traps both 2-4 m and >30 m from the chicken pens, the collapsible traps 2-4 m from the pens, and the gravid traps in backyards of houses with sentinel chicken pens and in a wetland adjacent to an urban area. We found numerous blood-engorged mosquitoes in the traps nearest to the sentinel chickens and reasoned that any such mosquitoes with a disseminated WNV infection likely served as vectors for the transmission of WNV to the sentinels. We used reverse transcriptase-polymerase chain reaction and isolation (C636) on pools of heads, thoraxes/ abdomens, and legs of collected blood-engorged mosquitoes to determine whether the mosquitoes carried WNV. We detected WNV-disseminated infections in and obtained WNV isolates from Culex nigripalpus Theo (minimum infection rate [MIR] 1.1-9.7/1,000), Culex bahamensis Dyar and Knab (MIR 1.8-6.0/1,000), and Aedes taeniorhynchus (Wied.) (MIR 0.34-0.36/1,000). WNV was also identified in and isolated from the pool of thoraxes and abdomens of Culex quinquefasciatus Say (4.17/1,000) and identified in one pool of thoraxes and abdomens of Culex habilitator Dyar and Knab (13.39/1,000). Accumulated evidence since 2002 suggests that WNV has not become endemic in Puerto Rico. PMID:21175071

  5. A review of the epidemiological and clinical aspects of West Nile virus

    Directory of Open Access Journals (Sweden)

    Gray TJ

    2014-04-01

    Full Text Available Timothy J Gray,1 Cameron E Webb2,31Department of Infectious Diseases, St Vincent's Hospital, Darlinghurst, NSW, Australia; 2Department of Medical Entomology, Centre for Infectious Diseases and Microbiology and Pathology West - Institute of Clinical Pathology and Medical Research, Westmead, NSW, Australia; 3Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, NSW, AustraliaAbstract: The resurgence of West Nile virus (WNV in North America and Europe in recent years has raised the concerns of local authorities and highlighted that mosquito-borne disease is not restricted to tropical regions of the world. WNV is maintained in enzootic cycles involving, primarily, Culex spp. mosquitoes and avian hosts, with epizootic spread to mammals, including horses and humans. Human infection results in symptomatic illness in approximately one-fifth of cases and neuroinvasive disease in less than 1% of infected persons. The most consistently recognized risk factor for neuroinvasive disease is older age, although diabetes mellitus, alcohol excess, and a history of cancer may also increase risk. Despite the increasing public health concern, the current WNV treatments are inadequate. Current evidence supporting the use of ribavirin, interferon α, and WNV-specific immunoglobulin are reviewed. Nucleic acid detection has been an important diagnostic development, which is particularly important for the protection of the donated blood supply. While effective WNV vaccines are widely available for horses, no human vaccine has been registered. Uncertainty surrounds the magnitude of future risk posed by WNV, and predictive models are limited by the heterogeneity of environmental, vector, and host factors, even in neighboring regions. However, recent history has demonstrated that for regions where suitable mosquito vectors and reservoir hosts are present, there will be a risk of major epidemics. Given the potential for these outbreaks to

  6. Proximity of Residence to Bodies of Water and Risk for West Nile Virus Infection: A Case-Control Study in Houston, Texas

    OpenAIRE

    Nolan, Melissa S.; Ana Zangeneh; Khuwaja, Salma A.; Diana Martinez; Rossmann, Susan N.; Victor Cardenas; Murray, Kristy O.

    2012-01-01

    West Nile virus (WNV), a mosquito-borne virus, has clinically affected hundreds of residents in the Houston metropolitan area since its introduction in 2002. This study aimed to determine if living within close proximity to a water source increases one’s odds of infection with WNV. We identified 356 eligible WNV-positive cases and 356 controls using a population proportionate to size model with US Census Bureau data. We found that living near slow moving water sources was statistically associ...

  7. The geosimulation of West Nile virus propagation: a multi-agent and climate sensitive tool for risk management in public health

    OpenAIRE

    Moulin Bernard; Bouden Mondher; Gosselin Pierre

    2008-01-01

    Abstract Background Since 1999, the expansion of the West Nile virus (WNV) epizooty has led public health authorities to build and operate surveillance systems in North America. These systems are very useful to collect data, but cannot be used to forecast the probable spread of the virus in coming years. Such forecasts, if proven reliable, would permit preventive measures to be put into place at the appropriate level of expected risk and at the appropriate time. It is within this context that...

  8. Comprehensive mapping of common immunodominant epitopes in the West Nile virus nonstructural protein 1 recognized by avian antibody responses.

    Directory of Open Access Journals (Sweden)

    Encheng Sun

    Full Text Available West Nile virus (WNV is a mosquito-borne flavivirus that primarily infects birds but occasionally infects humans and horses. Certain species of birds, including crows, house sparrows, geese, blue jays and ravens, are considered highly susceptible hosts to WNV. The nonstructural protein 1 (NS1 of WNV can elicit protective immune responses, including NS1-reactive antibodies, during infection of animals. The antigenicity of NS1 suggests that NS1-reactive antibodies could provide a basis for serological diagnostic reagents. To further define serological reagents for diagnostic use, the antigenic sites in NS1 that are targeted by host immune responses need to be identified and the potential diagnostic value of individual antigenic sites also needs to be defined. The present study describes comprehensive mapping of common immunodominant linear B-cell epitopes in the WNV NS1 using avian WNV NS1 antisera. We screened antisera from chickens, ducks and geese immunized with purified NS1 for reactivity against 35 partially overlapping peptides covering the entire WNV NS1. This study identified twelve, nine and six peptide epitopes recognized by chicken, duck and goose antibody responses, respectively. Three epitopes (NS1-3, 14 and 24 were recognized by antibodies elicited by immunization in all three avian species tested. We also found that NS1-3 and 24 were WNV-specific epitopes, whereas the NS1-14 epitope was conserved among the Japanese encephalitis virus (JEV serocomplex viruses based on the reactivity of avian WNV NS1 antisera against polypeptides derived from the NS1 sequences of viruses of the JEV serocomplex. Further analysis showed that the three common polypeptide epitopes were not recognized by antibodies in Avian Influenza Virus (AIV, Newcastle Disease Virus (NDV, Duck Plague Virus (DPV and Goose Parvovirus (GPV antisera. The knowledge and reagents generated in this study have potential applications in differential diagnostic approaches and

  9. Community diversity of mosquitoes and their microbes across different habitats endemic for West Nile Virus and other arthropod-borne diseases

    Science.gov (United States)

    Liu, R.; Bennett, S. N.; Thongsripong, P.; Chandler, J. S.

    2013-12-01

    Mosquitoes have long been vectors for disease, and humans, birds, and other vertebrates have served their role as hosts in the transmission cycle of arthropod-borne viruses. In California, there are several mosquito species that act as vectors, transmitting such disease agents as Western equine and St. Louis encephalitis viruses, filarial nematodes, Plasmodium (which causes malaria), and West Nile virus (WNV). Last year (2012-2013), California had over 450 reported cases of West Nile Virus in humans (http://westnile.ca.gov/). To begin to understand mosquitoes and their role in the bay area as vectors of diseases, including West Nile Virus, we trapped mosquitoes from various sites and examined their microbiomes, including bacteria, fungi, viruses, and eukaryotes. Study sites were in Marin, San Mateo, and San Francisco counties, in areas that represented, respectively, rural, suburban, and urban habitats. The mosquitoes were identified through morphological characteristics, and verified molecularly by sequencing of the cytochrome oxidase I (COI) gene extracted from a leg. Most mosquitoes were collected from San Mateo and Mill Valley and were identified as Culiseta incidens. Data from traditional culture-based and next-generation 454 sequencing methods applied to mosquito whole bodies, representing their microbiomes, will be discussed, to determine how mosquito and microbial diversity varies across sites sampled in the San Francisco Bay area.

  10. Local impact of temperature and precipitation on West Nile virus infection in Culex species mosquitoes in northeast Illinois, USA

    Directory of Open Access Journals (Sweden)

    Haramis Linn

    2010-03-01

    Full Text Available Abstract Background Models of the effects of environmental factors on West Nile virus disease risk have yielded conflicting outcomes. The role of precipitation has been especially difficult to discern from existing studies, due in part to habitat and behavior characteristics of specific vector species and because of differences in the temporal and spatial scales of the published studies. We used spatial and statistical modeling techniques to analyze and forecast fine scale spatial (2000 m grid and temporal (weekly patterns of West Nile virus mosquito infection relative to changing weather conditions in the urban landscape of the greater Chicago, Illinois, region for the years from 2004 to 2008. Results Increased air temperature was the strongest temporal predictor of increased infection in Culex pipiens and Culex restuans mosquitoes, with cumulative high temperature differences being a key factor distinguishing years with higher mosquito infection and higher human illness rates from those with lower rates. Drier conditions in the spring followed by wetter conditions just prior to an increase in infection were factors in some but not all years. Overall, 80% of the weekly variation in mosquito infection was explained by prior weather conditions. Spatially, lower precipitation was the most important variable predicting stronger mosquito infection; precipitation and temperature alone could explain the pattern of spatial variability better than could other environmental variables (79% explained in the best model. Variables related to impervious surfaces and elevation differences were of modest importance in the spatial model. Conclusion Finely grained temporal and spatial patterns of precipitation and air temperature have a consistent and significant impact on the timing and location of increased mosquito infection in the northeastern Illinois study area. The use of local weather data at multiple monitoring locations and the integration of mosquito

  11. Mosquito, bird and human surveillance of West Nile and Usutu viruses in Emilia-Romagna Region (Italy in 2010.

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    Mattia Calzolari

    Full Text Available BACKGROUND: In 2008, after the first West Nile virus (WNV detection in the Emilia-Romagna region, a surveillance system, including mosquito- and bird-based surveillance, was established to evaluate the virus presence. Surveillance was improved in following years by extending the monitoring to larger areas and increasing the numbers of mosquitoes and birds tested. METHODOLOGY/PRINCIPAL FINDINGS: A network of mosquito traps, evenly distributed and regularly activated, was set up within the surveyed area. A total of 438,558 mosquitoes, grouped in 3,111 pools and 1,276 birds (1,130 actively sampled and 146 from passive surveillance, were tested by biomolecular analysis. The survey detected WNV in 3 Culex pipiens pools while Usutu virus (USUV was found in 89 Cx. pipiens pools and in 2 Aedes albopictus pools. Two birds were WNV-positive and 12 were USUV-positive. Furthermore, 30 human cases of acute meningoencephalitis, possibly caused by WNV or USUV, were evaluated for both viruses and 1,053 blood bags were tested for WNV, without any positive result. CONCLUSIONS/SIGNIFICANCE: Despite not finding symptomatic human WNV infections during 2010, the persistence of the virus, probably due to overwintering, was confirmed through viral circulation in mosquitoes and birds, as well as for USUV. In 2010, circulation of the two viruses was lower and more delayed than in 2009, but this decrease was not explained by the relative abundance of Cx. pipiens mosquito, which was greater in 2010. The USUV detection in mosquito species confirms the role of Cx. pipiens as the main vector and the possible involvement of Ae. albopictus in the virus cycle. The effects of meteorological conditions on the presence of USUV-positive mosquito pools were considered finding an association with drought conditions and a wide temperature range. The output produced by the surveillance system demonstrated its usefulness and reliability in terms of planning public health policies.

  12. The Integrated System for Public Health Monitoring of West Nile Virus (ISPHM-WNV: a real-time GIS for surveillance and decision-making

    Directory of Open Access Journals (Sweden)

    Lebel Germain

    2005-09-01

    Full Text Available Abstract Background After its first detection in North America in New York in 1999, West Nile virus was detected for the first time in 2002 in the province of Quebec, Canada. This situation forced the Government of Quebec to adopt a public health protection plan against the virus. The plan comprises several fields of intervention including the monitoring of human cases, Corvidae and mosquitoes in order to ensure the early detection of the presence of the virus in a particular area. To help support the monitoring activities, the Integrated System for Public Health Monitoring of West Nile Virus (ISPHM-WNV has been developed. Results The ISPHM-WNV is a real-time geographic information system for public health surveillance of West Nile virus and includes information on Corvidae, mosquitoes, humans, horses, climate, and preventive larvicide interventions. It has been in operation in the province of Quebec, Canada, since May 2003. The ISPHM-WNV facilitates the collection, localization, management and analysis of monitoring data; it also allows for the display of the results of analyses on maps, tables and statistical diagrams. Conclusion The system is very helpful for field workers in all regions of the province, as well as for central authorities. It represents the common authoritative source of data for analysis, exchange and decision-making.

  13. O vírus do Nilo Ocidental West Nile virus

    Directory of Open Access Journals (Sweden)

    Eduardo Furtado Flores

    2009-04-01

    árias brasileiras da área humana e animal temem que a infecção seja introduzida no país, onde provavelmente encontraria condições ecológicas para a sua disseminação e manutenção. Este artigo apresenta uma breve revisão dos principais aspectos epidemiológicos e clínico-patológicos da infecção pelo WNV, com ênfase na infecção de humanos, aves e eqüinos.West Nile virus (WNV is a Flavivirus maintained in nature through alternate cycles of infection in wild birds and haematophagus mosquitoes, mainly Culex sp. Natural infection by WNV has been demonstrated in more than 200 bird species, which present variable susceptibility to infection and disease. Corvids and passeriformes are particularly susceptible and develop high levels of viremia and mortality. Occasionally, the virus may be transmitted to mammals by mosquitoes feeding previously on viremic birds. Human and horses are highly susceptible to WNV infection and often develop fever, which may be followed by neurological infection and fatal meningoencephalitis. Originally identified in Uganda (1937, WNV infection remained for decades restricted to North Africa, East Asia, Middle East and Mediterranean Europe. In these areas, isolated cases of human and horse disease, or small outbreaks were occasionally reported. In 1999, the virus was introduced in New York, USA, where it caused mortality in thousands of wild and captive birds and infected hundreds of people, killing 21. Thereafter, the infection rapidly spread out over the US territory, causing thousands of human infections (more than 27.000 - around 1100 deaths and equine infections (more than 25.000 cases. WNV infection has also been detected in wild and domestic birds, horses and other mammals across Mexico, Central America and the Caribbean, and northern South America, indicating its dissemination southwards. In 2006, WNV was first identified as the agent of fatal neurological disease in three horses in Argentina, where it has been shown to be circulating in

  14. Vector Contact Rates on Eastern Bluebird Nestlings Do Not Indicate West Nile Virus Transmission in Henrico County, Virginia, USA

    Directory of Open Access Journals (Sweden)

    Kevin A. Caillouët

    2013-11-01

    Full Text Available Sensitive indicators of spatial and temporal variation in vector-host contact rates are critical to understanding the transmission and eventual prevention of arboviruses such as West Nile virus (WNV. Monitoring vector contact rates on particularly susceptible and perhaps more exposed avian nestlings may provide an advanced indication of local WNV amplification. To test this hypothesis we monitored WNV infection and vector contact rates among nestlings occupying nest boxes (primarily Eastern bluebirds; Sialia sialis, Turdidae across Henrico County, Virginia, USA, from May to August 2012. Observed host-seeking rates were temporally variable and associated with absolute vector and host abundances. Despite substantial effort to monitor WNV among nestlings and mosquitoes, we did not detect the presence of WNV in these populations. Generally low vector-nestling host contact rates combined with the negative WNV infection data suggest that monitoring transmission parameters among nestling Eastern bluebirds in Henrico County, Virginia, USA may not be a sensitive indicator of WNV activity.

  15. West Nile and st. Louis encephalitis viruses antibodies surveillance in captive and free-ranging birds of prey from Argentina.

    Science.gov (United States)

    Quaglia, Agustin I; Diaz, Luis A; Argibay, Hernan; Contigiani, Marta S; Saggese, Miguel D

    2014-12-01

    We evaluated the prevalence of WNV and SLEV neutralizing antibodies in captive and free-ranging raptors from Argentina by plaque-reduction neutralization test. Eighty plasma samples from 12 species were analyzed. Only one captive adult Crowned Eagle (Harpyhaliaetus coronatus) was WNV seropositive (prevalence: 1.25%; antibody titer of 1:80). Two captive Crowned Eagles were SLEV seropositive (prevalence: 2.50%; antibody titers: 1:80 and 1:40).These findings expand the geographic distribution of WNV and SLEV and confirm their activity in central and northeastern Argentina. West Nile virus activity in Argentina may represent a potential threat to Crowned Eagles and other endangered raptors in this country.

  16. West Nile and st. Louis encephalitis viruses antibodies surveillance in captive and free-ranging birds of prey from Argentina.

    Science.gov (United States)

    Quaglia, Agustin I; Diaz, Luis A; Argibay, Hernan; Contigiani, Marta S; Saggese, Miguel D

    2014-12-01

    We evaluated the prevalence of WNV and SLEV neutralizing antibodies in captive and free-ranging raptors from Argentina by plaque-reduction neutralization test. Eighty plasma samples from 12 species were analyzed. Only one captive adult Crowned Eagle (Harpyhaliaetus coronatus) was WNV seropositive (prevalence: 1.25%; antibody titer of 1:80). Two captive Crowned Eagles were SLEV seropositive (prevalence: 2.50%; antibody titers: 1:80 and 1:40).These findings expand the geographic distribution of WNV and SLEV and confirm their activity in central and northeastern Argentina. West Nile virus activity in Argentina may represent a potential threat to Crowned Eagles and other endangered raptors in this country. PMID:25106849

  17. Progress in West Nile virus research%西尼罗病毒的研究进展

    Institute of Scientific and Technical Information of China (English)

    靳寿华; 张海林

    2009-01-01

    西尼罗病毒(West Nile Virus,WNV)属黄病毒科,为正单链RNA病毒,主要由蚊虫叮咬传播.近几年,随着WNV感染的流行,除蚊虫叮咬以外的传播途径如输血等日益受到重视,WNV感染的实验室诊断不断取得进展,相关疫苗的研制也在进行之中.本文就WNV的分子生物学、流行病学、感染与免疫、实验室诊断及疫苗的研究进展作一综述.

  18. Wetlands Management and risk for West Nile Virus Circulation in Camargue, Southern France

    Science.gov (United States)

    Leblond, Agnes; Pradier, Sophie; Paul, Mathilde; Lecollinet, Sylvie; Sandoz, Alain

    2016-04-01

    West Nile Virus (WNV) is a flavivirus transmitted between mosquitoes (mainly the genus Culex) and wild birds. Horses and humans are incidental hosts and can develop severe neurological disorders. During last decades, the number of WNV cases reported in Europe has increased dramatically. Large outbreaks of increased clinical severity have been reported in parts of Russia, Southern and Eastern Europe. In the Camargue area, WNV outbreaks have been reported in 2000, 2004 and more recently in 2015. We hypothesize that the management of Camargue wetlands could play a key role in the emergence of outbreaks in this area during recent years. WNV transmission requires competent vectors, receptive hosts, and environmental parameters which allow contact between the vectors and the different hosts. The Rhône Delta is known for its landscape of wetlands and its wealth of different bird species. It is also a region where mosquito populations are very abundant. Recent observations have shown that environmental changes, mainly resulting from anthropogenic practices, have had an impact on inter-annual variations in the wetlands and consequently on the abundance of mosquitoes. Water is provided either by rainfall or by a very tight canal network diverted from the river Rhone. Water management is under the control of individual field owners and dependent on its various uses (grazing, rice culture, hunting reserves). This specific management of water resources could play a role in the circulation of WNV in the area. Non-vaccinated horses (n = 1159 from 134 stables) were sampled in 2007 and 2008 in the Camargue area and a serological test was performed to identify a possible contact with the WNV. Environmental variables related to water resources and management were collected through fifteen Landsat images. Areas with open water and flooded vegetation and their variations within a year and between years (2007-08) were quantified for buffers of 2 km radius around the stables. Mean

  19. Predictive Modeling of West Nile Virus Transmission Risk in the Mediterranean Basin: How Far from Landing?

    OpenAIRE

    Véronique Chevalier; Annelise Tran; Benoit Durand

    2013-01-01

    The impact on human and horse health of West Nile fever (WNF) recently and dramatically increased in Europe and neighboring countries. Involving several mosquito and wild bird species, WNF epidemiology is complex. Despite the implementation of surveillance systems in several countries of concern, and due to a lack of knowledge, outbreak occurrence remains unpredictable. Statistical models may help identifying transmission risk factors. When spatialized, they provide tools to identify areas th...

  20. Ecology of West Nile virus across four European countries: review of weather profiles, vector population dynamics and vector control response.

    Science.gov (United States)

    Chaskopoulou, Alexandra; L'Ambert, Gregory; Petric, Dusan; Bellini, Romeo; Zgomba, Marija; Groen, Thomas A; Marrama, Laurence; Bicout, Dominique J

    2016-01-01

    West Nile virus (WNV) represents a serious burden to human and animal health because of its capacity to cause unforeseen and large epidemics. Until 2004, only lineage 1 and 3 WNV strains had been found in Europe. Lineage 2 strains were initially isolated in 2004 (Hungary) and in 2008 (Austria) and for the first time caused a major WNV epidemic in 2010 in Greece with 262 clinical human cases and 35 fatalities. Since then, WNV lineage 2 outbreaks have been reported in several European countries including Italy, Serbia and Greece. Understanding the interaction of ecological factors that affect WNV transmission is crucial for preventing or decreasing the impact of future epidemics. The synchronous co-occurrence of competent mosquito vectors, virus, bird reservoir hosts, and susceptible humans is necessary for the initiation and propagation of an epidemic. Weather is the key abiotic factor influencing the life-cycles of the mosquito vector, the virus, the reservoir hosts and the interactions between them. The purpose of this paper is to review and compare mosquito population dynamics, and weather conditions, in three ecologically different contexts (urban/semi-urban, rural/agricultural, natural) across four European countries (Italy, France, Serbia, Greece) with a history of WNV outbreaks. Local control strategies will be described as well. Improving our understanding of WNV ecology is a prerequisite step for appraising and optimizing vector control strategies in Europe with the ultimate goal to minimize the probability of WNV infection.

  1. Ecology of West Nile virus across four European countries: review of weather profiles, vector population dynamics and vector control response.

    Science.gov (United States)

    Chaskopoulou, Alexandra; L'Ambert, Gregory; Petric, Dusan; Bellini, Romeo; Zgomba, Marija; Groen, Thomas A; Marrama, Laurence; Bicout, Dominique J

    2016-01-01

    West Nile virus (WNV) represents a serious burden to human and animal health because of its capacity to cause unforeseen and large epidemics. Until 2004, only lineage 1 and 3 WNV strains had been found in Europe. Lineage 2 strains were initially isolated in 2004 (Hungary) and in 2008 (Austria) and for the first time caused a major WNV epidemic in 2010 in Greece with 262 clinical human cases and 35 fatalities. Since then, WNV lineage 2 outbreaks have been reported in several European countries including Italy, Serbia and Greece. Understanding the interaction of ecological factors that affect WNV transmission is crucial for preventing or decreasing the impact of future epidemics. The synchronous co-occurrence of competent mosquito vectors, virus, bird reservoir hosts, and susceptible humans is necessary for the initiation and propagation of an epidemic. Weather is the key abiotic factor influencing the life-cycles of the mosquito vector, the virus, the reservoir hosts and the interactions between them. The purpose of this paper is to review and compare mosquito population dynamics, and weather conditions, in three ecologically different contexts (urban/semi-urban, rural/agricultural, natural) across four European countries (Italy, France, Serbia, Greece) with a history of WNV outbreaks. Local control strategies will be described as well. Improving our understanding of WNV ecology is a prerequisite step for appraising and optimizing vector control strategies in Europe with the ultimate goal to minimize the probability of WNV infection. PMID:27590848

  2. Preclinical and Clinical Development of a YFV 17 D-Based Chimeric Vaccine against West Nile Virus

    Directory of Open Access Journals (Sweden)

    Gustavo H. Dayan

    2013-12-01

    Full Text Available Substantial success has been achieved in the development and implementation of West Nile (WN vaccines for horses; however, no human WN vaccines are approved. This review focuses on the construction, pre-clinical and clinical characterization of ChimeriVax-WN02 for humans, a live chimeric vaccine composed of a yellow fever (YF 17D virus in which the prM-E envelope protein genes are replaced with the corresponding genes of the WN NY99 virus. Pre-clinical studies demonstrated that ChimeriVax-WN02 was significantly less neurovirulent than YF 17D in mice and rhesus and cynomolgus monkeys. The vaccine elicited neutralizing antibody titers after inoculation in hamsters and monkeys and protected immunized animals from lethal challenge including intracerebral inoculation of high dose of WN NY99 virus. Safety, viremia and immunogenicity of ChimeriVax-WN02 were assessed in one phase I study and in two phase II clinical trials. No safety signals were detected in the three clinical trials with no remarkable differences in incidence of adverse events (AEs between vaccine and placebo recipients. Viremia was transient and the mean viremia levels were low. The vaccine elicited strong and durable neutralizing antibody and cytotoxic T cell responses. WN epidemiology impedes a classical licensure pathway; therefore, innovative licensure strategies should be explored.

  3. Factors associated with mosquito pool positivity and the characterization of the West Nile viruses found within Louisiana during 2007

    Directory of Open Access Journals (Sweden)

    Roy Alma F

    2010-06-01

    Full Text Available Abstract Background West Nile virus (WNV is an arbovirus of public health importance in the genus Flavivirus, a group of positive sense RNA viruses. The NS3 gene has a high level of substitutions and is phylogenetically informative. Likewise, substitutions in the envelope region have been postulated to enable viruses to subvert immune responses. Analysis of these genes among isolates from positive mosquitoes collected in Louisiana illustrates the variation present in the regions and provides improved insight to a phylogenetic model. Employing a GIS eco-regionalization method, we hypothesized that WNV pool positivity was correlated with regional environmental characteristics. Further, we postulated that the phylogenetic delineations would be associated with variations in regional environmental conditions. Results Type of regional land cover was a significant effect (p Conclusions The phylogenetic analysis shows that there has been no reversion in Louisiana from the 2002 lineage which replaced the originally introduced strain. Our pool positivity model serves as a basis for future testing, and could direct mosquito control and surveillance efforts. Understanding how land cover and regional ecology effects mosquito pool positivity will greatly help focus mosquito abatement efforts. This would especially help in areas where abatement programs are limited due to either funding or man power. Moreover, understanding how regional environments drive phylogenetic variation will lead to a greater understanding of the interactions between ecology and disease prevalence.

  4. The West Nile virus assembly process evades the conserved antiviral mechanism of the interferon-induced MxA protein.

    Science.gov (United States)

    Hoenen, Antje; Gillespie, Leah; Morgan, Garry; van der Heide, Peter; Khromykh, Alexander; Mackenzie, Jason

    2014-01-01

    Flaviviruses have evolved means to evade host innate immune responses. Recent evidence suggests this is due to prevention of interferon production and signaling in flavivirus-infected cells. Here we show that the interferon-induced MxA protein can sequester the West Nile virus strain Kunjin virus (WNVKUN) capsid protein in cytoplasmic tubular structures in an expression-replication system. This sequestering resulted in reduced titers of secreted WNVKUN particles. We show by electron microscopy, tomography and 3D modeling that these cytoplasmic tubular structures form organized bundles. Additionally we show that recombinant ER-targeted MxA can restrict production of infectious WNVKUN under conditions of virus infection. Our results indicate a co-ordinated and compartmentalized WNVKUN assembly process may prevent recognition of viral components by MxA, particularly the capsid protein. This recognition can be exploited if MxA is targeted to intracellular sites of WNVKUN assembly. This results in further understanding of the mechanisms of flavivirus evasion from the immune system.

  5. Fluid spatial dynamics of West Nile virus in the USA: Rapid spread in a permissive host environment

    Science.gov (United States)

    Di Giallonardo , Francesca; Geoghegan, Jemma L.; Docherty, Douglas E.; McLean, Robert G.; Zody, Michael C.; Qu, James; Yang, Xiao; Birren, Bruce W.; Malboeuf, Christine M.; Newman, R.; Ip, Hon S.; Holmes, Edward C.

    2016-01-01

    The introduction of West Nile virus (WNV) into North America in 1999 is a classical example of viral emergence in a new environment, with its subsequent dispersion across the continent having a major impact on local bird populations. Despite the importance of this epizootic, the pattern, dynamics and determinants of WNV spread in its natural hosts remain uncertain. In particular, it is unclear whether the virus encountered major barriers to transmission, or spread in an unconstrained manner, and if specific viral lineages were favored over others indicative of intrinsic differences in fitness. To address these key questions in WNV evolution and ecology we sequenced the complete genomes of approximately 300 avian isolates sampled across the USA between 2001-2012. Phylogenetic analysis revealed a relatively ‘star-like' tree structure, indicative of explosive viral spread in US, although with some replacement of viral genotypes through time. These data are striking in that viral sequences exhibit relatively limited clustering according to geographic region, particularly for those viruses sampled from birds, and no strong phylogenetic association with well sampled avian species. The genome sequence data analysed here also contain relatively little evidence for adaptive evolution, particularly on structural proteins, suggesting that most viral lineages are of similar fitness, and that WNV is well adapted to the ecology of mosquito vectors and diverse avian hosts in the USA. In sum, the molecular evolution of WNV in North America depicts a largely unfettered expansion within a permissive host and geographic population with little evidence of major adaptive barriers.

  6. 78 FR 16505 - Prospective Grant of Exclusive License: Chimeric West Nile/Dengue Viruses

    Science.gov (United States)

    2013-03-15

    ... business in San Diego, California. The patent rights in these inventions have been assigned to the... virus exhibits much more robust viral replication in cell cultures, compared to the slow growing DEN viruses. The chimeric WN/DEN virus can be used as a substitute for wild-type dengue virus in...

  7. Effects of climate on West Nile Virus transmission risk used for public health decision-making in Quebec

    Directory of Open Access Journals (Sweden)

    Gosselin Pierre L

    2007-09-01

    Full Text Available Abstract Background In 2002, major human epidemics of West Nile Virus (WNV were reported in five cities in the North East region of North America. The present analysis examines the climatic conditions that were conducive to the WNV epidemic, in order to provide information to public health managers who eventually must decide on the implementation of a preventive larvicide spraying program in Quebec, Canada. Two sets of variables, the first observed in the summer of 2002 and the second in the preceding winter were analysed to study their potential as explanatory variables for the emergence of the virus at epidemic levels. Results Results show that the climatic conditions observed in the year 2002 have contributed to the emergence of the virus and can be observed once every forty years on average. The analysis has shown that the 2002 events observed in several North East North American cities are characterized by two main variables: the number of degree-days below -5°C in the winter (DD-5 and the number of degree-days greater than 25°C in the summer (DD25. Conclusion In the context of a declining rate of human and aviary infection to WNV, this element contributed to the decision to suspend the use of preventive larvicides in the province of Quebec in 2006 and for the foreseeable future. The second part of this study indicates that it is very important to estimate the risk that extreme values can be observed simultaneously in the summer and in the winter preceding the appearance of the virus. The proposed models provide important information to public health officials, weeks before the appearance of the virus, and can therefore be useful to help prevent human epidemics.

  8. trans-Packaged West Nile virus-like particles: infectious properties in vitro and in infected mosquito vectors.

    Science.gov (United States)

    Scholle, Frank; Girard, Yvette A; Zhao, Qizu; Higgs, Stephen; Mason, Peter W

    2004-11-01

    A trans-packaging system for West Nile virus (WNV) subgenomic replicon RNAs (repRNAs), deleted for the structural coding region, was developed. WNV repRNAs were efficiently encapsidated by the WNV C/prM/E structural proteins expressed in trans from replication-competent, noncytopathic Sindbis virus-derived RNAs. Infectious virus-like particles (VLPs) were produced in titers of up to 10(9) infectious units/ml. WNV VLPs established a single round of infection in a variety of different cell lines without production of progeny virions. The infectious properties of WNV and VLPs were indistinguishable when efficiencies of infection of a number of different cell lines and inhibition of infection by neutralizing antibodies were determined. To investigate the usefulness of VLPs to address biological questions in vivo, Culex pipiens quinquefasciatus mosquitoes were orally and parenterally infected with VLPs, and dissected tissues were analyzed for WNV antigen expression. Antigen-positive cells in midguts of orally infected mosquitoes were detected as early as 2 days postinfection and as late as 8 days. Intrathoracic inoculation of VLPs into mosquitoes demonstrated a dose-dependent pattern of infection of secondary tissues and identified fat body, salivary glands, tracheal cells, and midgut muscle as susceptible WNV VLP infection targets. These results demonstrate that VLPs can serve as a valuable tool for the investigation of tissue tropism during the early stages of infection, where virus spread and the need for biosafety level 3 containment complicate the use of wild-type virus. PMID:15479801

  9. ¿Ha oído hablar del West Nile Virus? - PSA (:30) (The Buzz About West Nile Virus PSA [:30])

    Centers for Disease Control (CDC) Podcasts

    2012-08-21

    Este Anuncio de Servicio Público de 30 segundos explica cómo protegerse del Virus del Nilo Occidental. Creado: 8/21/2012 por los Centros para el Control y la Prevención de Enfermedades (CDC).  Created: 8/21/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 8/21/2012.

  10. A review of the vector management methods to prevent and control outbreaks of West Nile virus infection and the challenge for Europe.

    Science.gov (United States)

    Bellini, Romeo; Zeller, Herve; Van Bortel, Wim

    2014-01-01

    West Nile virus infection is a growing concern in Europe. Vector management is often the primary option to prevent and control outbreaks of the disease. Its implementation is, however, complex and needs to be supported by integrated multidisciplinary surveillance systems and to be organized within the framework of predefined response plans. The impact of the vector control measures depends on multiple factors and the identification of the best combination of vector control methods is therefore not always straightforward. Therefore, this contribution aims at critically reviewing the existing vector control methods to prevent and control outbreaks of West Nile virus infection and to present the challenges for Europe.Most West Nile virus vector control experiences have been recently developed in the US, where ecological conditions are different from the EU and vector control is organized under a different regulatory frame. The extrapolation of information produced in North America to Europe might be limited because of the seemingly different epidemiology in the European region. Therefore, there is an urgent need to analyse the European experiences of the prevention and control of outbreaks of West Nile virus infection and to perform robust cost-benefit analysis that can guide the implementation of the appropriate control measures. Furthermore, to be effective, vector control programs require a strong organisational backbone relying on a previously defined plan, skilled technicians and operators, appropriate equipment, and sufficient financial resources. A decision making guide scheme is proposed which may assist in the process of implementation of vector control measures tailored on specific areas and considering the available information and possible scenarios. PMID:25015004

  11. Risk communication, the West Nile virus epidemic, and bioterrorism: responding to the commnication challenges posed by the intentional or unintentional release of a pathogen in an urban setting

    OpenAIRE

    Covello, Vincent T.; Peters, Richard G.; Wojtecki, Joseph G.; Hyde, Richard C.

    2001-01-01

    The intentional or unintentional introduction of a pathogen in an urban setting presents severe communication chanllenges. Risk communication—a science-based approach for communicating effectively in high-concern situations—provides a set of principles and tools for meeting those challenges. A brief overview of the risk communication theoretical perspective and basic risk communication models is presented here, and the risk communication perspective is applied to the West Nile virus epidemic ...

  12. Protonation of Individual Histidine Residues Is Not Required for the pH-Dependent Entry of West Nile Virus: Evaluation of the “Histidine Switch” Hypothesis▿

    OpenAIRE

    Nelson, Steevenson; Poddar, Subhajit; Lin, Tsai-Yu; Pierson, Theodore C.

    2009-01-01

    Histidine residues have been hypothesized to function as sensors of environmental pH that can trigger the activity of viral fusion proteins. We investigated a requirement for histidine residues in the envelope (E) protein of West Nile virus during pH-dependent entry into cells. Each histidine was individually replaced with a nonionizable amino acid and tested functionally. In each instance, mutants capable of orchestrating pH-dependent infection were identified. These results do not support a...

  13. Quantitative Label-Free Phosphoproteomics Reveals Differentially Regulated Protein Phosphorylation Involved in West Nile Virus-Induced Host Inflammatory Response.

    Science.gov (United States)

    Zhang, Hao; Sun, Jun; Ye, Jing; Ashraf, Usama; Chen, Zheng; Zhu, Bibo; He, Wen; Xu, Qiuping; Wei, Yanming; Chen, Huanchun; Fu, Zhen F; Liu, Rong; Cao, Shengbo

    2015-12-01

    West Nile virus (WNV) can cause neuro-invasive and febrile illness that may be fatal to humans. The production of inflammatory cytokines is key to mediating WNV-induced immunopathology in the central nervous system. Elucidating the host factors utilized by WNV for productive infection would provide valuable insights into the evasion strategies used by this virus. Although attempts have been made to determine these host factors, proteomic data depicting WNV-host protein interactions are limited. We applied liquid chromatography-tandem mass spectrometry for label-free, quantitative phosphoproteomics to systematically investigate the global phosphorylation events induced by WNV infection. Quantifiable changes to 1,657 phosphoproteins were found; of these, 626 were significantly upregulated and 227 were downregulated at 12 h postinfection. The phosphoproteomic data were subjected to gene ontology enrichment analysis, which returned the inflammation-related spliceosome, ErbB, mitogen-activated protein kinase, nuclear factor kappa B, and mechanistic target of rapamycin signaling pathways. We used short interfering RNAs to decrease the levels of glycogen synthase kinase-3 beta, bifunctional polynucleotide phosphatase/kinase, and retinoblastoma 1 and found that the activity of nuclear factor kappa B (p65) is significantly decreased in WNV-infected U251 cells, which in turn led to markedly reduced inflammatory cytokine production. Our results provide a better understanding of the host response to WNV infection and highlight multiple targets for the development of antiviral and anti-inflammatory therapies.

  14. West Nile Virus Temperature Sensitivity and Avian Virulence Are Modulated by NS1-2B Polymorphisms.

    Science.gov (United States)

    Dietrich, Elizabeth A; Langevin, Stanley A; Huang, Claire Y-H; Maharaj, Payal D; Delorey, Mark J; Bowen, Richard A; Kinney, Richard M; Brault, Aaron C

    2016-08-01

    West Nile virus (WNV) replicates in a wide variety of avian species, which serve as reservoir and amplification hosts. WNV strains isolated in North America, such as the prototype strain NY99, elicit a highly pathogenic response in certain avian species, notably American crows (AMCRs; Corvus brachyrhynchos). In contrast, a closely related strain, KN3829, isolated in Kenya, exhibits a low viremic response with limited mortality in AMCRs. Previous work has associated the difference in pathogenicity primarily with a single amino acid mutation at position 249 in the helicase domain of the NS3 protein. The NY99 strain encodes a proline residue at this position, while KN3829 encodes a threonine. Introduction of an NS3-T249P mutation in the KN3829 genetic background significantly increased virulence and mortality; however, peak viremia and mortality were lower than those of NY99. In order to elucidate the viral genetic basis for phenotype variations exclusive of the NS3-249 polymorphism, chimeric NY99/KN3829 viruses were created. We show herein that differences in the NS1-2B region contribute to avian pathogenicity in a manner that is independent of and additive with the NS3-249 mutation. Additionally, NS1-2B residues were found to alter temperature sensitivity when grown in avian cells. PMID:27548738

  15. Short communication. Further evidence of lineage 2 West Nile Virus in Culex pipiens of North-Eastern Italy

    Directory of Open Access Journals (Sweden)

    Gioia Capelli

    2013-09-01

    Full Text Available West Nile Virus lineage 1 (WNV lin1 emerged in North-Eastern Italy in 2008 and, since then, it has been detected in animals, humans and mosquitoes. Three years later, in the same area, a lineage 2 (lin2 strain of WNV was found in birds and vectors. On August the 21st, during the 2012 WNV entomological surveillance plan, a WNV lin2 strain was detected by RT-PCR in a pool of Culex pipiens mosquitoes captured in Veneto region. According to the alignment of the partial sequences of the NS5 and NS3 genes, no differences between this Italian lineage 2 strain and the Nea Santa-Greece-2010 WNV isolate (Gr-10 were observed. Similarly to the Gr-10 strain, the putative NS3 aminoacid sequences of the Italian strain showed proline in position 249 instead of histidine (H249P. Although proline in position 249 has been suggested to increase the virulence of WNV strains, neither human nor veterinary cases associated to this strain have been reported in the region. A prompt mosquito disinfestation was organized to avoid the spread of this potential threatening virus. The simultaneous circulation of both WNV lineage 1 and 2 confirms North-Eastern Italy as a high risk area for WNV emergence and highlights the need for a continuous surveillance.

  16. Conserved amino acids within the N-terminus of the West Nile virus NS4A protein contribute to virus replication, protein stability and membrane proliferation

    International Nuclear Information System (INIS)

    The West Nile virus strain Kunjin virus (WNVKUN) NS4A protein is a multifunctional protein involved in many aspects of the virus life-cycle and is a major component of the WNVKUN replication complex (RC). Previously we identified a conserved region in the C-terminus of NS4A regulating proteolytic processing and RC assembly, and now investigate key conserved residues in the N-terminus of NS4A and their contribution to WNVKUN replication. Mutation of P13 completely ablated replication, whereas, mutation of P48 and D49, near the first transmembrane helix, and G66 within the helix, showed variable defects in replication, virion secretion and membrane proliferation. Intriguingly, the P48 and G66 NS4A mutants resulted in specific proteasome depletion of NS4A that could in part be rescued with a proteasome inhibitor. Our results suggest that the N-terminus of NS4A contributes to correct folding and stability, essential for facilitating the essential roles of NS4A during replication. - Highlights: • Mutation of Proline13 of the WNV NS4A protein is lethal to replication. • 1st TMB helix of NS4A contributes to protein stability and membrane remodelling. • Unstable mutants of NS4A can be rescued with a proteasome inhibitor. • This study (and of others) contributes to a functional mapping of the NS4A protein

  17. Conserved amino acids within the N-terminus of the West Nile virus NS4A protein contribute to virus replication, protein stability and membrane proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Ambrose, R.L.; Mackenzie, J.M., E-mail: jason.mackenzie@unimelb.edu.au

    2015-07-15

    The West Nile virus strain Kunjin virus (WNV{sub KUN}) NS4A protein is a multifunctional protein involved in many aspects of the virus life-cycle and is a major component of the WNV{sub KUN} replication complex (RC). Previously we identified a conserved region in the C-terminus of NS4A regulating proteolytic processing and RC assembly, and now investigate key conserved residues in the N-terminus of NS4A and their contribution to WNV{sub KUN} replication. Mutation of P13 completely ablated replication, whereas, mutation of P48 and D49, near the first transmembrane helix, and G66 within the helix, showed variable defects in replication, virion secretion and membrane proliferation. Intriguingly, the P48 and G66 NS4A mutants resulted in specific proteasome depletion of NS4A that could in part be rescued with a proteasome inhibitor. Our results suggest that the N-terminus of NS4A contributes to correct folding and stability, essential for facilitating the essential roles of NS4A during replication. - Highlights: • Mutation of Proline13 of the WNV NS4A protein is lethal to replication. • 1st TMB helix of NS4A contributes to protein stability and membrane remodelling. • Unstable mutants of NS4A can be rescued with a proteasome inhibitor. • This study (and of others) contributes to a functional mapping of the NS4A protein.

  18. When to Spray: a Time-Scale Calculus Approach to Controlling the Impact of West Nile Virus

    Directory of Open Access Journals (Sweden)

    Robert A. Washington-Allen

    2009-12-01

    Full Text Available West Nile Virus (WNV made its initial appearance in the New York City (NYC metropolitan area in 1999 and was implicated in cases of human encephalitis and the extensive mortality in crows (Corvus sp. and other avian species. Mosquitoes were found to be the primary vectors and NYC's current policy on control strategies involved an eradication program that depends on the synchronicity of the summer mosquito population's increases with the occurrence of cases in humans. The purpose of this paper is to investigate whether this is the most effective control strategy because past mathematical models assumed discrete behavior that is modeled by difference equations for a single summer season was most important to the virus's life cycle. However, both surviving mosquito eggs and surviving migratory birds incubate the virus during the winter, leading to a continuation of infections in the following warmer spring and summer when the birds return and the eggs hatch. Additionally, the virulence of WNV has been observed to fluctuate with changes in temperature toward warmer conditions. Models are required that account for these multi-seasonal dynamics and time-scale calculus is a newly developed method for resolving the behavior of systems that exhibit both discrete and continuous behavior. We found that, although the static states of the new temperature delay model are no different from older models, simulations indicate that the rate of the infection is affected by avian recovery at a lower temperature threshold. Consequently, eradication strategies should consider that controlling mosquitoes during the fall when colder temperatures occur would cause a fast and efficient drop to a disease-free state. This could prove rather more effective than mosquito control in the warmer months.

  19. NMR analysis of the dynamic exchange of the NS2B cofactor between open and closed conformations of the West Nile virus NS2B-NS3 protease.

    Directory of Open Access Journals (Sweden)

    Xun-Cheng Su

    Full Text Available BACKGROUND: The two-component NS2B-NS3 proteases of West Nile and dengue viruses are essential for viral replication and established targets for drug development. In all crystal structures of the proteases to date, the NS2B cofactor is located far from the substrate binding site (open conformation in the absence of inhibitor and lining the substrate binding site (closed conformation in the presence of an inhibitor. METHODS: In this work, nuclear magnetic resonance (NMR spectroscopy of isotope and spin-labeled samples of the West Nile virus protease was used to investigate the occurrence of equilibria between open and closed conformations in solution. FINDINGS: In solution, the closed form of the West Nile virus protease is the predominant conformation irrespective of the presence or absence of inhibitors. Nonetheless, dissociation of the C-terminal part of the NS2B cofactor from the NS3 protease (open conformation occurs in both the presence and the absence of inhibitors. Low-molecular-weight inhibitors can shift the conformational exchange equilibria so that over 90% of the West Nile virus protease molecules assume the closed conformation. The West Nile virus protease differs from the dengue virus protease, where the open conformation is the predominant form in the absence of inhibitors. CONCLUSION: Partial dissociation of NS2B from NS3 has implications for the way in which the NS3 protease can be positioned with respect to the host cell membrane when NS2B is membrane associated via N- and C-terminal segments present in the polyprotein. In the case of the West Nile virus protease, discovery of low-molecular-weight inhibitors that act by breaking the association of the NS2B cofactor with the NS3 protease is impeded by the natural affinity of the cofactor to the NS3 protease. The same strategy can be more successful in the case of the dengue virus NS2B-NS3 protease.

  20. Remote sensing of climatic anomalies and West Nile virus incidence in the northern Great Plains of the United States.

    Science.gov (United States)

    Chuang, Ting-Wu; Wimberly, Michael C

    2012-01-01

    The northern Great Plains (NGP) of the United States has been a hotspot of West Nile virus (WNV) incidence since 2002. Mosquito ecology and the transmission of vector-borne disease are influenced by multiple environmental factors, and climatic variability is an important driver of inter-annual variation in WNV transmission risk. This study applied multiple environmental predictors including land surface temperature (LST), the normalized difference vegetation index (NDVI) and actual evapotranspiration (ETa) derived from Moderate-Resolution Imaging Spectroradiometer (MODIS) products to establish prediction models for WNV risk in the NGP. These environmental metrics are sensitive to seasonal and inter-annual fluctuations in temperature and precipitation, and are hypothesized to influence mosquito population dynamics and WNV transmission. Non-linear generalized additive models (GAMs) were used to evaluate the influences of deviations of cumulative LST, NDVI, and ETa on inter-annual variations of WNV incidence from 2004-2010. The models were sensitive to the timing of spring green up (measured with NDVI), temperature variability in early spring and summer (measured with LST), and moisture availability from late spring through early summer (measured with ETa), highlighting seasonal changes in the influences of climatic fluctuations on WNV transmission. Predictions based on these variables indicated a low WNV risk across the NGP in 2011, which is concordant with the low case reports in this year. Environmental monitoring using remote-sensed data can contribute to surveillance of WNV risk and prediction of future WNV outbreaks in space and time. PMID:23071656

  1. Remote sensing of climatic anomalies and West Nile virus incidence in the northern Great Plains of the United States.

    Directory of Open Access Journals (Sweden)

    Ting-Wu Chuang

    Full Text Available The northern Great Plains (NGP of the United States has been a hotspot of West Nile virus (WNV incidence since 2002. Mosquito ecology and the transmission of vector-borne disease are influenced by multiple environmental factors, and climatic variability is an important driver of inter-annual variation in WNV transmission risk. This study applied multiple environmental predictors including land surface temperature (LST, the normalized difference vegetation index (NDVI and actual evapotranspiration (ETa derived from Moderate-Resolution Imaging Spectroradiometer (MODIS products to establish prediction models for WNV risk in the NGP. These environmental metrics are sensitive to seasonal and inter-annual fluctuations in temperature and precipitation, and are hypothesized to influence mosquito population dynamics and WNV transmission. Non-linear generalized additive models (GAMs were used to evaluate the influences of deviations of cumulative LST, NDVI, and ETa on inter-annual variations of WNV incidence from 2004-2010. The models were sensitive to the timing of spring green up (measured with NDVI, temperature variability in early spring and summer (measured with LST, and moisture availability from late spring through early summer (measured with ETa, highlighting seasonal changes in the influences of climatic fluctuations on WNV transmission. Predictions based on these variables indicated a low WNV risk across the NGP in 2011, which is concordant with the low case reports in this year. Environmental monitoring using remote-sensed data can contribute to surveillance of WNV risk and prediction of future WNV outbreaks in space and time.

  2. Mosquito larval habitat mapping using remote sensing and GIS: Implications of coalbed methane development and West Nile virus

    Energy Technology Data Exchange (ETDEWEB)

    Zou, L.; Miller, S.N.; Schmidtmann, E.T. [University of Wyoming, Laramie, WY (United States). Dept. of Renewable Resources

    2006-09-15

    Potential larval habitats of the mosquito Culex tarsalis (Coquillett), implicated as a primary vector of West Nile virus in Wyoming, were identified using integrated remote sensing and geographic information system (GIS) analyses. The study area is in the Powder River Basin of north central Wyoming, an area that has been undergoing a significant increase in coalbed methane gas extractions since the late 1990s. Large volumes of water are discharged, impounded, and released during the extraction of methane gas, creating aquatic habitats that have the potential to support immature mosquito development. Landsat TM and ETM + data were initially classified into spectrally distinct water and vegetation classes, which were in turn used to identify suitable larval habitat sites. This initial habitat classification was refined using knowledge-based GIS techniques requiring spatial data layers for topography, streams, and soils to reduce the potential for overestimation of habitat. Accuracy assessment was carried out using field data and high-resolution aerial photography commensurate with one of the Landsat images. The classifier can identify likely habitat for ponds larger than 0.8 ha (2 acres) with generally satisfactory results (72.1%) with a lower detection limit of approximate to 0.4 ha (1 acre). Results show a 75% increase in potential larval habitats from 1999 to 2004 in the study area, primarily because of the large increase in small coalbed methane water discharge ponds. These results may facilitate mosquito abatement programs in the Powder River Basin with the potential for application throughout the state and region.

  3. Passive transfer of naturally acquired specific immunity against West Nile Virus to foals in a semi-feral pony herd.

    Science.gov (United States)

    Wilkins, Pamela A; Glaser, Amy L; McDonnell, Sue M

    2006-01-01

    Horses naturally exposed to West Nile Virus (WNV) or vaccinated against WNV develop humoral immunity thought to be protective against development of clinical disease in exposed or infected animals. No reports evaluate the efficacy of passive transfer of naturally acquired specific WNV humoral immunity from dam to foal. The purpose of this study was to investigate passive transfer of naturally acquired immunity to WNV to foals born in a herd of semi-feral ponies, not vaccinated against WNV, in an endemic area, with many dams having seroconverted because of natural exposure. Microwell serum neutralization titers against WNV were determined in all mares and foals. Serum IgG concentration was determined in foals by serial radial immunodiffusion. Differences in IgG concentration between seropositive and seronegative foals were examined by means of the Mann-Whitney U-test. Linear regression was used to evaluate the association between mare and foal titers. Seventeen mare-foal pairs were studied; 1 foal had inadequate IgG concentration. IgG concentration was not different between seronegative and seropositive foals (P = .24). Mare and foal titers were significantly correlated in foals with adequate passive transfer of immunity (Spearman's rho = .84; P 90% of the foal's titer was explained by the mare's titer (R2 = 0.91; P immunity to WNV is present in pony foals with adequate passive transfer of immunity born to seroconverted mares.

  4. Age-Dependent Cell Trafficking Defects in Draining Lymph Nodes Impair Adaptive Immunity and Control of West Nile Virus Infection.

    Directory of Open Access Journals (Sweden)

    Justin M Richner

    2015-07-01

    Full Text Available Impaired immune responses in the elderly lead to reduced vaccine efficacy and increased susceptibility to viral infections. Although several groups have documented age-dependent defects in adaptive immune priming, the deficits that occur prior to antigen encounter remain largely unexplored. Herein, we identify novel mechanisms for compromised adaptive immunity that occurs with aging in the context of infection with West Nile virus (WNV, an encephalitic flavivirus that preferentially causes disease in the elderly. An impaired IgM and IgG response and enhanced vulnerability to WNV infection during aging was linked to delayed germinal center formation in the draining lymph node (DLN. Adoptive transfer studies and two-photon intravital microscopy revealed a decreased trafficking capacity of donor naïve CD4+ T cells from old mice, which manifested as impaired T cell diapedesis at high endothelial venules and reduced cell motility within DLN prior to antigen encounter. Furthermore, leukocyte accumulation in the DLN within the first few days of WNV infection or antigen-adjuvant administration was diminished more generally in old mice and associated with a second aging-related defect in local cytokine and chemokine production. Thus, age-dependent cell-intrinsic and environmental defects in the DLN result in delayed immune cell recruitment and antigen recognition. These deficits compromise priming of early adaptive immune responses and likely contribute to the susceptibility of old animals to acute WNV infection.

  5. Identification of Culex pipiens complex mosquitoes in a hybrid zone of West Nile virus transmission in Fresno County, California.

    Science.gov (United States)

    McAbee, Rory D; Green, Emily N; Holeman, Jodie; Christiansen, Julie; Frye, Niki; Dealey, Katherine; Mulligan, F Steve; Brault, Aaron C; Cornel, Anthony J

    2008-02-01

    Culex pipiens sensu lato mosquitoes were collected from 24 gravid traps (mid-June to mid-October, 2005) in Fresno County, CA. Captured gravid females were allowed to oviposit before sibling species identification by Ace.2 PCR and detection of West Nile virus (WNV) RNA by RT-PCR were performed on the mother and her offspring. Of the 442 Cx. pipiens s.l. female mosquitoes collected, 88 were positive for WNV viral RNA (peaked in August) with no significant differences among complex members or habitat. Vertical transmission was detected in 4 out of 20 families originating from WNV-positive mothers, however, in only a small number of offspring from each family. Out of 101 families that had PCR-based maternal and offspring identifications, the offspring from 15 families produced inexplicable amplicon patterns, suggesting ambiguities in the PCR assay identifications. Male genitalia (DV/D ratio) and Ace.2 PCR identifications revealed numerous discrepancies in our ability to accurately determine the identity of Cx. pipiens complex members in the hybrid zone of Fresno County.

  6. Identification of Genes Critical for Resistance to Infection by West Nile Virus Using RNA-Seq Analysis

    Directory of Open Access Journals (Sweden)

    Mark Gerstein

    2013-07-01

    Full Text Available The West Nile virus (WNV is an emerging infection of biodefense concern and there are no available treatments or vaccines. Here we used a high-throughput method based on a novel gene expression analysis, RNA-Seq, to give a global picture of differential gene expression by primary human macrophages of 10 healthy donors infected in vitro with WNV. From a total of 28 million reads per sample, we identified 1,514 transcripts that were differentially expressed after infection. Both predicted and novel gene changes were detected, as were gene isoforms, and while many of the genes were expressed by all donors, some were unique. Knock-down of genes not previously known to be associated with WNV resistance identified their critical role in control of viral infection. Our study distinguishes both common gene pathways as well as novel cellular responses. Such analyses will be valuable for translational studies of susceptible and resistant individuals—and for targeting therapeutics—in multiple biological settings.

  7. Spatio-temporal cluster analysis of county-based human West Nile virus incidence in the continental United States

    Directory of Open Access Journals (Sweden)

    DeGroote John P

    2009-07-01

    Full Text Available Abstract Background West Nile virus (WNV is a vector-borne illness that can severely affect human health. After introduction on the East Coast in 1999, the virus quickly spread and became established across the continental United States. However, there have been significant variations in levels of human WNV incidence spatially and temporally. In order to quantify these variations, we used Kulldorff's spatial scan statistic and Anselin's Local Moran's I statistic to uncover spatial clustering of human WNV incidence at the county level in the continental United States from 2002–2008. These two methods were applied with varying analysis thresholds in order to evaluate sensitivity of clusters identified. Results The spatial scan and Local Moran's I statistics revealed several consistent, important clusters or hot-spots with significant year-to-year variation. In 2002, before the pathogen had spread throughout the country, there were significant regional clusters in the upper Midwest and in Louisiana and Mississippi. The largest and most consistent area of clustering throughout the study period was in the Northern Great Plains region including large portions of Nebraska, South Dakota, and North Dakota, and significant sections of Colorado, Wyoming, and Montana. In 2006, a very strong cluster centered in southwest Idaho was prominent. Both the spatial scan statistic and the Local Moran's I statistic were sensitive to the choice of input parameters. Conclusion Significant spatial clustering of human WNV incidence has been demonstrated in the continental United States from 2002–2008. The two techniques were not always consistent in the location and size of clusters identified. Although there was significant inter-annual variation, consistent areas of clustering, with the most persistent and evident being in the Northern Great Plains, were demonstrated. Given the wide variety of mosquito species responsible and the environmental conditions they

  8. Epidemiology of West Nile virus: a silent epiornitic in Northern Delaware in 2007 without associated human cases.

    Science.gov (United States)

    Gingrich, Jack B; O'Connor, Linda-Lou; Meredith, William H; Pesek, John D; Shriver, W Gregory

    2010-09-01

    ABSTRACT. We performed a 2-year longitudinal study (2006-2007) of West Nile virus (WNV) infections in wild birds, mosquitoes, and sentinel chickens at 6 WNV-endemic sites in northern Delaware. We determined virus infection rates of Culex pipiens and other mosquito vectors as well as seroprevalence and antibody titers of amplifying hosts. Endemicity status varied widely among the 6 sites based on 3 criteria-mosquito infections, sentinel chicken seropositivity, and wild bird seropositivity. A highly endemic site would display at least 2 of the 3 criteria during each year of the study, while a site with just 1 positive criterion was considered to have low endemicity. Culex pipiens was the principal vector detected at 2 highly endemic sites in 2006 vs. 1 site in 2007. However, in 2006, we also found 2 other WNV-positive vector species as well as an unidentifiable Culex species at 1 highly endemic site, suggesting increased activity at the end of the 1st year of the study. Wild birds were early indicators of WNV at highly endemic sites in mid-July to early August of both 2006-2007. Mosquitoes were positive in mid- to late August, appearing concurrently with seroconverted sentinel chickens, with wild resident birds appearing approximately 4 wk prior to those indicators. Of birds tested with n > or = 9, Northern cardinals had the highest seropositivity rates (47%) followed by Carolina wrens (19%), house sparrows (13%), American robins (13%), tufted titmice (11%), and gray catbirds (9%). The overall seropositive rates in trapped birds increased from 5.0% in 2006 to 20.0% in 2007, while the geometric mean titers of all positive birds increased from 1:34 to 1:47 during the comparable periods. Based on these results, we suggest that an epiornitic in birds occurred in 2007, but that greatly reduced abundance of mosquito vectors caused by an extreme drought largely precluded human infection.

  9. A temporal role of type I interferon signaling in CD8+ T cell maturation during acute West Nile virus infection.

    Directory of Open Access Journals (Sweden)

    Amelia K Pinto

    2011-12-01

    Full Text Available A genetic absence of the common IFN-α/β signaling receptor (IFNAR in mice is associated with enhanced viral replication and altered adaptive immune responses. However, analysis of IFNAR(-/- mice is limited for studying the functions of type I IFN at discrete stages of viral infection. To define the temporal functions of type I IFN signaling in the context of infection by West Nile virus (WNV, we treated mice with MAR1-5A3, a neutralizing, non cell-depleting anti-IFNAR antibody. Inhibition of type I IFN signaling at or before day 2 after infection was associated with markedly enhanced viral burden, whereas treatment at day 4 had substantially less effect on WNV dissemination. While antibody treatment prior to infection resulted in massive expansion of virus-specific CD8(+ T cells, blockade of type I IFN signaling starting at day 4 induced dysfunctional CD8(+ T cells with depressed cytokine responses and expression of phenotypic markers suggesting exhaustion. Thus, only the later maturation phase of anti-WNV CD8(+ T cell development requires type I IFN signaling. WNV infection experiments in BATF3(-/- mice, which lack CD8-α dendritic cells and have impaired priming due to inefficient antigen cross-presentation, revealed a similar effect of blocking IFN signaling on CD8(+ T cell maturation. Collectively, our results suggest that cell non-autonomous type I IFN signaling shapes maturation of antiviral CD8(+ T cell response at a stage distinct from the initial priming event.

  10. The human and animal health impacts of introduction and spread of an exotic strain of West Nile virus in Australia.

    Science.gov (United States)

    Hernández-Jover, Marta; Roche, Sharon; Ward, Michael P

    2013-05-01

    Vector-borne diseases can have substantial impacts on human and animal health, including major epidemics. West Nile virus (WNV) is of particular international importance due to its recent emergence and impact in the Western Hemisphere. Despite the presence of a sub-type of WNV (Kunjin virus, KUN) in Australia, a potential ecological niche could be occupied by an exotic strain of WNV of the North American type. This study assesses the probability an exotic strain of WNV enters Australia via an infected mosquito in an aircraft from the United States (U.S.) landing at Sydney airport, the probability it spreads to susceptible species and the impact of the resulting outbreak on human and animal health. A release, exposure and consequence assessment were conducted using expert opinion and scientific literature to parameterise the inputs for the models (OIE, 2009). Following establishment of WNV in Australia, the spatio-temporal spread of WNV was predicted over a six year period based on the Australian human and equine populations at-risk, the known distribution of other mosquito-borne flaviviruses in Australia, climatic factors, and the spread of WNV in the U.S. following it's incursion in New York City in 1999. The impact of this spread was measured as a multiplier of human and equine demographics using the U.S. incidence and case fatality rates as a reference. For an 8 month period from September to April (considering seasonal impact on mosquito activity during the coldest months in Australia and the U.S.), and assuming WNV is endemic in the U.S., the median probability an infected mosquito is introduced is 0.17, and the median number of infected mosquitoes introduced is predicted to be zero, with a 95th percentile range of one. The overall probability of a WNV outbreak (WNV released into Australia, susceptible hosts exposed and the virus spread) occurring in the human and the horse population during this time period is estimated to be 7.0×10(-6) and 3.9×10

  11. Toxicological Safety Evaluation of DNA Plasmid Vaccines against HIV-1, Ebola, Severe Acute Respiratory Syndrome, or West Nile Virus Is Similar Despite Differing Plasmid Backbones or Gene-Inserts

    OpenAIRE

    Sheets, Rebecca L.; Stein, Judith; Manetz, T. Scott; Andrews, Charla; Bailer, Robert; Rathmann, John; Gomez, Phillip L.

    2006-01-01

    The Vaccine Research Center has developed a number of vaccine candidates for different diseases/infectious agents (HIV-1, Severe Acute Respiratory Syndrome virus, West Nile virus, and Ebola virus, plus a plasmid cytokine adjuvant—IL-2/Ig) based on a DNA plasmid vaccine platform. To support the clinical development of each of these vaccine candidates, preclinical studies were performed to screen for potential toxicities (intrinsic and immunotoxicities). All treatment-related toxicities identif...

  12. Simultaneous detection of West Nile virus and Chikungunya virus by duplex real-time quantitative PCR%双重荧光定量PCR检测西尼罗病毒和基孔肯雅病毒

    Institute of Scientific and Technical Information of China (English)

    余蓓蓓; 卢亦愚; 谢鑫友; 徐昌平; 张钧

    2013-01-01

    目的 建立同时检测西尼罗病毒(WNV)、基孔肯雅病毒(CHIKV)的双重荧光定量PCR法,为临床疑似病例的诊断提供依据.方法 分别针对WNV CAP基因、CHIKV E1基因保守区设计特异性引物和TaqMan探针,建立并优化双重荧光定量PCR反应体系,评价方法的特异性和灵敏度.结果 建立的双重荧光定量PCR可同时检测WNV、CHIKV核酸,标准曲线相关系数(r)分别达0.999、0.998,灵敏度达10 copies/μL,具有良好的特异性.结论 建立了同时检测WNV、CHIKV的双重荧光定量PCR法,但尚需临床进一步验证.%Objective To develop a duplex real-time quantitative PCR assay for simultaneous detection of West Nile virus and Chikungunya virus.Methods Two sets of primers and TaqMan probes were designed based on highly conserved CAP gene region of West Nile virus and E1 gene region of Chikungunya virus,and the reactive condition of duplex real-time PCR was optimized.The sensitivity and specificity of the assay were evaluated.Results The duplex real-time quantitative PCR assay showed excellent specificity in simultaneous detection of West Nile virus and Chikungunya virus.The sensitivities of the assay were 10 copies/μL for both the virus,and the correlation coefficient of the quantitative curve were 0.999 and 0.998 respectively.Conclusion The duplex fluorescent quantitative PCR assay developed in this study is sensitive and specific for simultaneous detection of West Nile virus and Chikungunya virus.The efficiency of the assay for detecting of clinical samples should be further evaluated.

  13. Full-Genome Sequence of a Neuroinvasive West Nile Virus Lineage 2 Strain from a Fatal Horse Infection in South Africa.

    Science.gov (United States)

    Mentoor, Juliet L D; Lubisi, Alison B; Gerdes, Truuska; Human, Stacey; Williams, June H; Venter, Marietjie

    2016-01-01

    We report here the complete genome sequence of a lineage 2 West Nile virus (WNV) strain that resulted in fatal neurological disease in a horse in South Africa. Several recent reports exist of neurological disease associated with lineage 2 WNV in humans and horses in South Africa and Europe; however, there are a lack of sequencing data from recent fatal cases in Southern Africa, where these strains likely originate. A better understanding of the genetic composition of highly neuroinvasive lineage 2 strains may facilitate the identification of putative genetic factors associated with increased virulence. PMID:27469963

  14. Full-Genome Sequence of a Neuroinvasive West Nile Virus Lineage 2 Strain from a Fatal Horse Infection in South Africa

    Science.gov (United States)

    Mentoor, Juliet L. D.; Lubisi, Alison B.; Gerdes, Truuska; Human, Stacey; Williams, June H.

    2016-01-01

    We report here the complete genome sequence of a lineage 2 West Nile virus (WNV) strain that resulted in fatal neurological disease in a horse in South Africa. Several recent reports exist of neurological disease associated with lineage 2 WNV in humans and horses in South Africa and Europe; however, there are a lack of sequencing data from recent fatal cases in Southern Africa, where these strains likely originate. A better understanding of the genetic composition of highly neuroinvasive lineage 2 strains may facilitate the identification of putative genetic factors associated with increased virulence. PMID:27469963

  15. West Nile Virus transmission in winter: the 2013 Great Salt Lake Bald Eagle and Eared Grebes Mortality event

    Science.gov (United States)

    Ip, Hon S.; Van Wettere, Arnaud J.; McFarlan, Leslie; Shearn-Bochsler, Valerie I.; Dickson, Sammie L.; Baker, JoDee; Hatch, Gary; Cavender, Kimberly; Long, Renee Romaine; Bodenstein, Barbara L.

    2014-01-01

    West Nile Virus (WNV) infection has been reported in over 300 species of birds and mammals. Raptors such as eagles, hawks and falcons are remarkably susceptible, but reports of WNV infection in Bald Eagles (Haliaeetus leucocephalus) are rare and reports of WNV infection in grebes (Podicipediformes) even rarer. We report an unusually large wild bird mortality event involving between 15,000-20,000 Eared Grebes (Podiceps nigricollis) and over 40 Bald Eagles around the Great Salt Lake, Utah, in November-December 2013. Mortality in grebes was first reported in early November during a period when the area was unseasonably warm and the grebes were beginning to gather and stage prior to migration. Ten out of ten Eared Grebes collected during this period were WNV RT-PCR and/or isolation positive. This is the first report of WNV infection in Eared Grebes and the associated mortality event is matched in scale only by the combined outbreaks in American White Pelican (Pelecanus erythrorhynchos) colonies in the north central states in 2002-2003. We cannot be sure that all of the grebes were infected by mosquito transmission; some may have become infected through contact with WNV shed orally or cloacally from other infected grebes. Beginning in early December, Bald Eagles in the Great Salt Lake area were observed to display neurological signs such as body tremors, limb paralysis and lethargy. At least 43 Bald Eagles had died by the end of the month. Nine of nine Bald Eagles examined were infected with WNV. To the best of our knowledge, this is the largest single raptor mortality event since WNV became endemic in the USA. Because the majority of the eagles affected were found after onset of below-freezing temperatures, we suggest at least some of the Bald Eagles were infected with WNV via consumption of infected Eared Grebes or horizontal transmission at roost sites.

  16. Ecological Forecasting of West Nile Virus Outbreaks in a High-Risk Area of the North-Central United States

    Science.gov (United States)

    Wimberly, M. C.; Merkord, C. L.; Kightlinger, L.; Vincent, G.; Hildreth, M. B.

    2015-12-01

    West Nile virus (WNV) is the most widespread and important mosquito-borne pathogen in North America. Since its emergence in the western hemisphere in 1999, human WNV disease has continued to exhibit recurrent outbreaks. Perplexingly, the incidence of this tropical disease has been highest in the cold-temperate climates of the Northern Great Plains (NGP). The spatial and temporal distributions of the vector mosquitoes and bird hosts, and consequently the risk of disease in humans, are strongly influenced by temperature, precipitation, vegetation, soils, and land use. We have utilized satellite remote sensing to map these environmental factors through time and develop models of disease risk. Outbreak years in South Dakota were preceded by warm winters, and WNV cases were most likely to occur during the hottest weeks of summer. Hot spots of persistent WNV transmission within the state were associated with rural land cover as well as patterns of physiography and climate. These models are currently being integrated into the South Dakota Mosquito Early Warning system (SDMIS), an automated WNV outbreak detection system that integrates remotely-sensed environmental indicators with vector abundance and infection data from a statewide mosquito surveillance network. The major goal of this effort is to leverage global environmental monitoring datasets to provide up-to-date, locally relevant information that can improve the effectiveness of mosquito control and disease prevention activities. This system was implemented for the first time during the summer of 2015. We will review the outcomes of this implementation, including the underlying influences of temperature on WNV risk, a preliminary statewide WNV risk map, and dynamic risk predictions made during the 2015 WNV season. Lessons learned as well as plans for future years will be discussed.

  17. Modeled response of the West Nile virus vector Culex quinquefasciatus to changing climate using the dynamic mosquito simulation model

    Science.gov (United States)

    Morin, Cory W.; Comrie, Andrew C.

    2010-09-01

    Climate can strongly influence the population dynamics of disease vectors and is consequently a key component of disease ecology. Future climate change and variability may alter the location and seasonality of many disease vectors, possibly increasing the risk of disease transmission to humans. The mosquito species Culex quinquefasciatus is a concern across the southern United States because of its role as a West Nile virus vector and its affinity for urban environments. Using established relationships between atmospheric variables (temperature and precipitation) and mosquito development, we have created the Dynamic Mosquito Simulation Model (DyMSiM) to simulate Cx. quinquefasciatus population dynamics. The model is driven with climate data and validated against mosquito count data from Pasco County, Florida and Coachella Valley, California. Using 1-week and 2-week filters, mosquito trap data are reproduced well by the model ( P mosquito population trends than moist locations in Florida. Florida and California mosquito populations are generally temperature-limited in winter. In California, locations are water-limited through much of the year. Using future climate projection data generated by the National Center for Atmospheric Research CCSM3 general circulation model, we applied temperature and precipitation offsets to the climate data at each location to evaluate mosquito population sensitivity to possible future climate conditions. We found that temperature and precipitation shifts act interdependently to cause remarkable changes in modeled mosquito population dynamics. Impacts include a summer population decline from drying in California due to loss of immature mosquito habitats, and in Florida a decrease in late-season mosquito populations due to drier late summer conditions.

  18. Landscape, demographic and climatic associations with human West Nile virus occurrence regionally in 2012 in the United States of America

    Directory of Open Access Journals (Sweden)

    John P. DeGroote

    2014-11-01

    Full Text Available After several years of low West Nile virus (WNV occurrence in the United States of America (USA, 2012 wit- nessed large outbreaks in several parts of the country. In order to understand the outbreak dynamics, spatial clustering and landscape, demographic and climatic associations with WNV occurrence were investigated at a regional level in the USA. Previous research has demonstrated that there are a handful of prominent WNV mosquito vectors with varying ecological requirements responsible for WNV transmission in the USA. Published range maps of these important vectors were georef- erenced and used to define eight functional ecological regions in the coterminous USA. The number of human WNV cases and human populations by county were attained in order to calculate a WNV rate for each county in 2012. Additionally, a binary value (high/low was calculated for each county based on whether the county WNV rate was above or below the rate for the region it fell in. Global Moran’s I and Anselin Local Moran’s I statistics of spatial association were used per region to examine and visualize clustering of the WNV rate and the high/low rating. Spatial data on landscape, demographic and climatic variables were compiled and derived from a variety of sources and then investigated in relation to human WNV using both Spearman rho correlation coefficients and Poisson regression models. Findings demonstrated significant spatial clustering of WNV and substantial inter-regional differences in relationships between WNV occurrence and landscape, demographic and climatically related variables. The regional associations were consistent with the ecologies of the dominant vectors for those regions. The large outbreak in the Southeast region was preceded by higher than normal winter and spring precipitation followed by dry and hot conditions in the summer.

  19. Ecology of potential West Nile virus vectors in southeastern Louisiana: enzootic transmission in the relative absence of Culex quinquefasciatus

    Science.gov (United States)

    Godsey, Marvin S.; King, Raymond J.; Burkhalter, Kristen; Delorey, Mark; Colton, Leah; Charnetzky, Dawn; Sutherland, Genevieve; Ezenwa, Vanessa O.; Wilson, Lawrence A.; Coffey, Michelle; Milheim, Lesley E.; Taylor, Viki G.; Palmisano, Charles; Wesson, Dawn M.; Guptill, Stephen C.

    2013-01-01

    A study of West Nile virus (WNV) ecology was conducted in St. Tammany Parish, Louisiana, from 2002 to 2004. Mosquitoes were collected weekly throughout the year using Centers for Disease Control and Prevention (CDC) light traps placed at 1.5 and 6 m above the ground and gravid traps. A total of 379,466 mosquitoes was collected. WNV was identified in 32 pools of mosquitoes comprising four species; 23 positive pools were from Culex nigripalpus collected during 2003. Significantly more positive pools were obtained from Cx. nigripalpus collected in traps placed at 6 m than 1.5 m that year, but abundance did not differ by trap height. In contrast, Cx. nigripalpus abundance was significantly greater in traps placed at 6 m in 2002 and 2004. Annual temporal variation in Cx. nigripalpus peak seasonal abundance has important implications for WNV transmission in Louisiana. One WNV-positive pool, from Cx. erraticus, was collected during the winter of 2004, showing year-round transmission. The potential roles of additional mosquito species in WNV transmission in southeastern Louisiana are discussed. Disclaimer: The opinions expressed in this article are the opinions of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention. This article has been peer reviewed and approved for publication consistent with U.S. Geological Survey Fundamental Science Practices (http//pubs.usgs.gov/circ/1367/). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  20. Lo que dicen del virus del Nilo Occidental (The Buzz-z-z on West Nile Virus)

    Centers for Disease Control (CDC) Podcasts

    2012-01-12

    En este podcast para niños, los chicos de Kidtastics hablan sobre el virus del Nilo Occidental y cómo protegerse de él.  Created: 1/12/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 1/30/2012.

  1. Aedes aegypti saliva alters leukocyte recruitment and cytokine signaling by antigen-presenting cells during West Nile virus infection.

    Directory of Open Access Journals (Sweden)

    Bradley S Schneider

    Full Text Available West Nile virus (WNV is transmitted during mosquito bloodfeeding. Consequently, the first vertebrate cells to contact WNV are cells in the skin, followed by those in the draining lymph node. Macrophages and dendritic cells are critical early responders in host defense against WNV infection, not just because of their role in orchestrating the immune response, but also because of their importance as sites of early peripheral viral replication. Antigen-presenting cell (APC signals have a profound effect on host antiviral responses and disease severity. During transmission, WNV is intimately associated with mosquito saliva. Due to the ability of mosquito saliva to affect inflammation and immune responses, and the importance of understanding early events in WNV infection, we investigated whether mosquito saliva alters APC signaling during arbovirus infection, and if alterations in cell recruitment occur when WNV infection is initiated with mosquito saliva. Accordingly, experiments were performed with cultured dendritic cells and macrophages, flow cytometry was used to characterize infiltrating cell types in the skin and lymph nodes during early infection, and real-time RT-PCR was employed to evaluate virus and cytokine levels. Our in vitro results suggest that mosquito saliva significantly decreases the expression of interferon-beta and inducible nitric oxide synthase in macrophages (by as much as 50 and 70%, respectively, whilst transiently enhancing interleukin-10 (IL-10 expression. In vivo results indicate that the predominate effect of mosquito feeding is to significantly reduce the recruitment of T cells, leading the inoculation site of mice exposed to WNV alone to have up to 2.8 fold more t cells as mice infected in the presence of mosquito saliva. These shifts in cell population are associated with significantly elevated IL-10 and WNV (up to 4.0 and 10 fold, respectively in the skin and draining lymph nodes. These results suggest that mosquito

  2. A comparison of West Nile virus surveillance using survival analyses of dead corvid and mosquito pool data in Ontario, 2002-2008.

    Science.gov (United States)

    Thomas-Bachli, Andrea L; Pearl, David L; Berke, Olaf; Parmley, Elizabeth Jane; Barker, Ian K

    2015-12-01

    The aim of this study was to improve understanding of the relative performance of the use of dead wild corvids and mosquito pools infected with West Nile virus (WNv) in surveillance for WNv activity in the environment. To this end, all records on dead corvid submissions and mosquito pools tested in Public Health Units (PHUs) in Ontario, from 2002 to 2008, were explored. Survival analyses were employed using the first-WNv-positive cases detected each year for each PHU, and censored observations for PHUs which did not detect WNv during a given year using each data source (504 observations). Survival analyses were employed to compare the number of surveillance weeks before WNv was detected by either data source, and the influence of temporal, geographic and sociodemographic factors on these data. The outcome measurement for the final accelerated failure time (AFT) model with log-logistic distribution was a time ratio, which represents the ratio of the survival time of one group relative to another. Dead corvid surveillance was faster at detecting WNv than testing mosquito pools during the early years of WNv incursion into Ontario, while mosquito testing found WNv more quickly later in the study period. There was also regional variation in time-to-detection of WNv, by modality, as well as for various types of urban/rural settings. In comparison to mosquito surveillance, West Nile virus was detected more quickly using dead corvid surveillance in sparsely populated regions. These areas may benefit from collection of dead corvids to optimize detection and direct early surveillance efforts. When we compared the time-to-detection of WNv using dead corvids and the onset of human cases in PHUs, we found that dead corvid surveillance was predictive of West Nile activity in health units that reported human cases during the first 3 years of the incursion into Ontario.

  3. Comparison of immune responses of brown-headed cowbird and related blackbirds to West Nile and other mosquito-borne encephalitis viruses

    Science.gov (United States)

    Reisen, W.K.; Hahn, D.C.

    2007-01-01

    The rapid geographic spread of West Nile virus (family Flaviviridae, genus Flavivirus, WNV) across the United States has stimulated interest in comparative host infection studies to delineate competent avian hosts critical for viral amplification. We compared the host competence of four taxonomically related blackbird species (Icteridae) after experimental infection with WNV and with two endemic, mosquito-borne encephalitis viruses, western equine encephalomyelitis virus (family Togaviridae, genus Alphavirus, WEEV), and St, Louis encephalitis virus (family Flaviviridae, genus Flavivirus, SLEV). We predicted differences in disease resistance among the blackbird species based on differences in life history, because they differ in geographic range and life history traits that include mating and breeding systems. Differences were observed among the response of these hosts to all three viruses, Red-winged Blackbirds were more susceptible to SLEV than Brewer's Blackbirds, whereas Brewer's Blackbirds were more susceptible to WEEV than Red-winged Blackbirds. In response to WNV infection, cowbirds showed the lowest mean viremias, cleared their infections faster, and showed lower antibody levels than concurrently infected species. Brown-headed Cowbirds also exhibited significantly lower viremia responses after infection with SLEV and WEEV as well as coinfection with WEEV and WNV than concurrently infected icterids. We concluded that cowbirds may be more resistant to infection to both native and introduced viruses because they experience heightened exposure to a variety of pathogens of parenting birds during the course of their parasitic life style.

  4. Experimental infection of rock pigeons (Columba livia) with three West Nile virus lineage 1 strains isolated in Italy between 2009 and 2012.

    Science.gov (United States)

    Spedicato, M; Carmine, I; Bellacicco, A L; Marruchella, G; Marini, V; Pisciella, M; Di Francesco, G; Lorusso, A; Monaco, F; Savini, G

    2016-04-01

    West Nile virus (WNV) circulation dynamics in the context of the urban environment is not yet elucidated. In this perspective, three groups of eight rock pigeons (Columbia livia) were inoculated with three WNV lineage 1 strains isolated in Italy between 2009 and 2012. The pigeons did not develop any clinical signs consistent with WNV acute infection. All animals seroconverted and shed virus up to 15 days post-infection by the oral or cloacal routes. In all infected groups viraemia lasted for 4 days post-infection. No WNV-specific gross or histological lesions were found in infected birds compared to control birds and immunohistochemistry remained constantly negative from all tissues. The reservoir competence index was also assessed and it ranged between 0·11 and 0·14. This study demonstrates that pigeons are competent reservoir hosts for Italian WNV lineage 1 circulating strains thus potentially posing a risk to the public health system. PMID:26493864

  5. Experimental infection of rock pigeons (Columba livia) with three West Nile virus lineage 1 strains isolated in Italy between 2009 and 2012.

    Science.gov (United States)

    Spedicato, M; Carmine, I; Bellacicco, A L; Marruchella, G; Marini, V; Pisciella, M; Di Francesco, G; Lorusso, A; Monaco, F; Savini, G

    2016-04-01

    West Nile virus (WNV) circulation dynamics in the context of the urban environment is not yet elucidated. In this perspective, three groups of eight rock pigeons (Columbia livia) were inoculated with three WNV lineage 1 strains isolated in Italy between 2009 and 2012. The pigeons did not develop any clinical signs consistent with WNV acute infection. All animals seroconverted and shed virus up to 15 days post-infection by the oral or cloacal routes. In all infected groups viraemia lasted for 4 days post-infection. No WNV-specific gross or histological lesions were found in infected birds compared to control birds and immunohistochemistry remained constantly negative from all tissues. The reservoir competence index was also assessed and it ranged between 0·11 and 0·14. This study demonstrates that pigeons are competent reservoir hosts for Italian WNV lineage 1 circulating strains thus potentially posing a risk to the public health system.

  6. Proximity of residence to bodies of water and risk for west nile virus infection: a case-control study in Houston, Texas.

    Science.gov (United States)

    Nolan, Melissa S; Zangeneh, Ana; Khuwaja, Salma A; Martinez, Diana; Rossmann, Susan N; Cardenas, Victor; Murray, Kristy O

    2012-01-01

    West Nile virus (WNV), a mosquito-borne virus, has clinically affected hundreds of residents in the Houston metropolitan area since its introduction in 2002. This study aimed to determine if living within close proximity to a water source increases one's odds of infection with WNV. We identified 356 eligible WNV-positive cases and 356 controls using a population proportionate to size model with US Census Bureau data. We found that living near slow moving water sources was statistically associated with increased odds for human infection, while living near moderate moving water systems was associated with decreased odds for human infection. Living near bayous lined with vegetation as opposed to concrete also showed increased risk of infection. The habitats of slow moving and vegetation lined water sources appear to favor the mosquito-human transmission cycle. These methods can be used by resource-limited health entities to identify high-risk areas for arboviral disease surveillance and efficient mosquito management initiatives.

  7. Research Advances: DNA Computing Targets West Nile Virus, Other Deadly Diseases, and Tic-Tac-Toe; Marijuana Component May Offer Hope for Alzheimer's Disease Treatment; New Wound Dressing May Lead to Maggot Therapy--Without the Maggots

    Science.gov (United States)

    King, Angela G.

    2007-01-01

    This article presents three reports of research advances. The first report describes a deoxyribonucleic acid (DNA)-based computer that could lead to faster, more accurate tests for diagnosing West Nile Virus and bird flu. Representing the first "medium-scale integrated molecular circuit," it is the most powerful computing device of its type to…

  8. Simultaneous detection and differentiation of dengue virus serotypes 1-4, Japanese encephalitis virus, and West Nile virus by a combined reverse-transcription loop-mediated isothermal amplification assay

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    Yin Jianhua

    2011-07-01

    Full Text Available Abstract Background Rapid identification and differentiation of mosquito-transmitted flaviviruses in acute-phase sera of patients and field-caught vector mosquitoes are important for the prediction and prevention of large-scale epidemics. Results We developed a flexible reverse-transcription loop-mediated isothermal amplification (RT-LAMP unit for the detection and differentiation of dengue virus serotypes 1-4 (DENV1-4, Japanese encephalitis virus (JEV, and West Nile virus (WNV. The unit efficiently amplified the viral genomes specifically at wide ranges of viral template concentrations, and exhibited similar amplification curves as monitored by a real-time PCR engine. The detection limits of the RT-LAMP unit were 100-fold higher than that of RT-PCR in 5 of the six flaviviruses. The results on specificity indicated that the six viruses in the assay had no cross-reactions with each other. By examining 66 viral strains of DENV1-4 and JEV, the unit identified the viruses with 100% accuracy and did not cross-react with influenza viruses and hantaviruses. By screening a panel of specimens containing sera of 168 patients and 279 pools of field-caught blood sucked mosquitoes, results showed that this unit is high feasible in clinical settings and epidemiologic field, and it obtained results 100% correlated with real-time RT-PCR. Conclusions The RT-LAMP unit developed in this study is able to quickly detect and accurately differentiate the six kinds of flaviviruses, which makes it extremely feasible for screening these viruses in acute-phase sera of the patients and in vector mosquitoes without the need of high-precision instruments.

  9. The E glycoprotein plays an essential role in the high pathogenicity of European-Mediterranean IS98 strain of West Nile virus.

    Science.gov (United States)

    Alsaleh, Khaled; Khou, Cécile; Frenkiel, Marie-Pascale; Lecollinet, Sylvie; Vàzquez, Ana; de Arellano, Eva Ramírez; Després, Philippe; Pardigon, Nathalie

    2016-05-01

    West Nile virus (WNV) is the most widespread arbovirus in the world. Several recent outbreaks and epizootics have been reported in Europe and the Mediterranean basin with increased virulence. In contrast to the well-characterized American and Australian strains, little is known about the virulence determinants of the WNV European-Mediterranean strains. To investigate the viral factors involved in the virulence of these strains, we generated chimeras between the highly neuropathogenic Israel 1998 (IS-98-ST1, IS98) strain and the non-pathogenic Malaysian Kunjin virus (KJMP-502). In vivo analyses in a mouse model of WNV pathogenesis shows that chimeric virus where KJMP-502 E glycoprotein was replaced by that of IS98 is neuropathogenic, demonstrating that this protein is a major virulence determinant. Presence of the N-glycosylation site had limited impact on virus virulence and the 5'UTR does not seem to influence pathogenesis. Finally, mice inoculated with KJMP-502 virus were protected against lethal IS98 infection.

  10. Association between HLA class I and class II alleles and the outcome of West Nile virus infection: an exploratory study.

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    Marion C Lanteri

    Full Text Available BACKGROUND: West Nile virus (WNV infection is asymptomatic in most individuals, with a minority developing symptoms ranging from WNV fever to serious neuroinvasive disease. This study investigated the impact of host HLA on the outcome of WNV disease. METHODS: A cohort of 210 non-Hispanic mostly white WNV(+ subjects from Canada and the U.S. were typed for HLA-A, B, C, DP, DQ, and DR. The study subjects were divided into three WNV infection outcome groups: asymptomatic (AS, symptomatic (S, and neuroinvasive disease (ND. Allele frequency distribution was compared pair-wise between the AS, S, and ND groups using χ2 and Fisher's exact tests and P values were corrected for multiple comparisons (Pc. Allele frequencies were compared between the groups and the North American population (NA used as a control group. Logistic regression analysis was used to evaluate the potential synergistic effect of age and HLA allele phenotype on disease outcome. RESULTS: The alleles HLA-A*68, C*08 and DQB*05 were more frequently associated with severe outcomes (ND vs. AS, P(A*68 = 0.013/Pc = 0.26, P(C*08 = 0.0075/Pc = 0.064, and P(DQB1*05 = 0.029/Pc = 0.68, However the apparent DQB1*05 association was driven by age. The alleles HLA-B*40 and C*03 were more frequently associated with asymptomatic outcome (AS vs. S, P(B*40 = 0.021/Pc = 0.58 and AS vs. ND P(C*03 = 0.039/Pc = 0.64 and their frequencies were lower within WNV(+ subjects with neuroinvasive disease than within the North American population (NA vs. S, P(B*40 = 0.029 and NA vs. ND, P(C*03 = 0.032. CONCLUSIONS: Host HLA may be associated with the outcome of WNV disease; HLA-A*68 and C*08 might function as "susceptible" alleles, whereas HLA-B*40 and C*03 might function as "protective" alleles.

  11. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae, in Mexico City

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    Diaz-Perez Alfonso

    2011-05-01

    Full Text Available Abstract Background Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids. Results Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected. Conclusions Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p

  12. Enhancing Remotely Sensed TIR Data for Public Health Applications: Is West Nile Virus Heat-Related?

    Science.gov (United States)

    Weng, Q.; Liu, H.; Jiang, Y.

    2014-12-01

    Public health studies often require thermal infrared (TIR) images at both high temporal and spatial resolution to retrieve LST. However, currently, no single satellite sensors can deliver TIR data at both high temporal and spatial resolution. This technological limitation prevents the wide usage of remote sensing data in epidemiological studies. To solve this issue, we have developed a few image fusion techniques to generate high temporally-resolved image data. We downscaled GOES LST data to 15-minute 1-km resolution to assess community-based heat-related risk in Los Angeles County, California and simulated ASTER datasets by fusing ASTER and MODIS data to derive biophysical variables, including LST, NDVI, and normalized difference water index, to examine the effects of those environmental characteristics on WNV outbreak and dissemination. A spatio-temporal analysis of WNV outbreak and dissemination was conducted by synthesizing the remote sensing variables and mosquito surveillance data, and by focusing on WNV risk areas in July through September due to data sufficiency of mosquito pools. Moderate- and high-risk areas of WNV infections in mosquitoes were identified for five epidemiological weeks. These identified WNV-risk areas were then collocated in GIS with heat hazard, exposure, and vulnerability maps to answer the question of whether WNV is a heat related virus. The results show that elevation and built-up conditions were negatively associated with the WNV propagation, while LST positively correlated with the viral transmission. NDVI was not significantly associated with WNV transmission. San Fernando Valley was found to be the most vulnerable to mosquito infections of WNV. This research provides important insights into how high temporal resolution remote sensing imagery may be used to study time-dependant events in public health, especially in the operational surveillance and control of vector-borne, water-borne, or other epidemic diseases.

  13. Culex pipiens and Stegomyia albopicta (= Aedes albopictus) populations as vectors for lineage 1 and 2 West Nile virus in Europe.

    Science.gov (United States)

    Brustolin, M; Talavera, S; Santamaría, C; Rivas, R; Pujol, N; Aranda, C; Marquès, E; Valle, M; Verdún, M; Pagès, N; Busquets, N

    2016-06-01

    The emerging disease West Nile fever is caused by West Nile virus (WNV), one of the most widespread arboviruses. This study represents the first test of the vectorial competence of European Culex pipiens Linnaeus 1758 and Stegomyia albopicta (= Aedes albopictus) (both: Diptera: Culicidae) populations for lineage 1 and 2 WNV isolated in Europe. Culex pipiens and S. albopicta populations were susceptible to WNV infection, had disseminated infection, and were capable of transmitting both WNV lineages. This is the first WNV competence assay to maintain mosquito specimens under environmental conditions mimicking the field (day/night) conditions associated with the period of maximum expected WNV activity. The importance of environmental conditions is discussed and the issue of how previous experiments conducted in fixed high temperatures may have overestimated WNV vector competence results with respect to natural environmental conditions is analysed. The information presented should be useful to policymakers and public health authorities for establishing effective WNV surveillance and vector control programmes. This would improve preparedness to prevent future outbreaks. PMID:26890285

  14. Vírus do Nilo Ocidental: nova ameaça à segurança transfusional? West Nile virus: a new threat to transfusion safety?

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    Audrey K. Zeinad

    2004-01-01

    Full Text Available O vírus do Nilo Ocidental (West Nile Virus é um RNA vírus, dos mais importantes flavivírus patogênicos em humanos. Devido ao número crescente de casos confirmados de infeção pelo vírus do Nilo Ocidental nos EUA a partir de 1999, com a documentação da sua disseminação da costa leste para a oeste e sul em um período inferior a três anos e pela sua disseminação em quatro continentes, medidas estão sendo implementadas para o controle dessa epidemia. A documentação da transmissão pela transfusão de sangue, órgãos transplantados, aleitamento materno e transmissão vertical e a observação de taxa significante de morbidade e mortalidade (variando de 4% a 29% está alarmando a comunidade médica internacional. Esforços estão sendo realizados na tentativa de obtenção de testes diagnósticos precisos, na busca de uma terapêutica eficaz - uma vez que o meio de controle mais efetivo no momento é o controle de vetores (insetos - e no desenvolvimento de vacinas. Tendo em vista a detecção de casos na América Central e pelas condições climáticas ideais do Brasil, devemos estar atentos quanto aos possíveis riscos dessa epidemia. Esse artigo apresenta o quadro atual mundial de disseminação, modos de transmissão, quadro clínico, diagnóstico e tratamento, e algumas medidas preventivas para o controle do vírus do Nilo Ocidental.The West Nile virus is an RNA virus and is one of the most important pathogenic flaviviruses in humans. Due to the increasing number of confirmed cases in the U.S.A since 1999, with documentation of its dissemination from the East coast to the West and South in less than three years and because of its spread over four continents, measures are being implemented to control this epidemic. The documented transmission through blood transfusion, transplanted organs, breast feeding and vertical transmission and the significant morbidity and mortality rates (4 to 29% is alarming the international medical

  15. Retrospective identification of human cases of West Nile virus infection in Austria (2009 to 2010) by serological differentiation from Usutu and other flavivirus infections.

    Science.gov (United States)

    Stiasny, K; Aberle, S W; Heinz, F X

    2013-01-01

    There is increasing evidence for the spread of West Nile virus (WNV) in southern, eastern and central Europe. In parallel, another flavivirus, the antigenically closely related Usutu virus, was introduced from Africa and first detected in Austria (2001), followed by Spain (2003), Hungary (2005), Italy (2006), Switzerland (2006) and Germany (2007). In Austria, human WNV infections have not previously been documented, although the virus was isolated from birds and detected in mosquitoes in 2008 and 2009. We therefore conducted a retrospective search for human cases of WNV infection using serum and cerebrospinal fluid samples collected from patients with central nervous system (CNS) disease in the summers of 2009, 2010 and 2011. Although all samples were negative for WNV by polymerase chain reaction, quantitative evaluation of standardised antibody assays with purified flavivirus antigens (including Usutu virus, which cross-reacts with WNV even in neutralisation assays) provided serological evidence for three autochthonous WNV infections in Austria: two in 2009 and one in 2010. Our data highlight the importance of raising awareness of WNV infections in Austria and neighbouring countries and suggest including testing for this infection in routine diagnostic practice of CNS diseases.

  16. Distribution and abundance of host-seeking Culex species at three proximate locations with different levels of West Nile virus activity

    Science.gov (United States)

    Rochlin, I.; Ginsberg, H.S.; Campbell, S.R.

    2009-01-01

    Culex species were monitored at three proximate sites with historically different West Nile virus (WNV) activities. The site with human WNV transmission (epidemic) had the lowest abundance of the putative bridge vectors, Culex pipiens and Cx. salinarius. The site with horse cases but not human cases (epizootic) had the highest percent composition of Cx. salinarius, whereas the site with WNV-positive birds only (enzootic) had the highest Cx. pipiens abundance and percent composition. A total of 29 WNV-positive Culex pools were collected at the enzootic site, 17 at the epidemic site, and 14 at the epizootic site. Published models of human risk using Cx. pipiens and Cx. salinarius as the primary bridge vectors did not explain WNV activity at our sites. Other variables, such as additional vector species, environmental components, and socioeconomic factors, need to be examined to explain the observed patterns of WNV epidemic activity.

  17. West Nile Virus

    Science.gov (United States)

    ... to protect themselves from mosquito bites by using mosquito repellent, especially at times when mosquitoes are most active, ... as at dusk and dawn. The CDC recommends mosquito repellents that include one of the following ingredients: DEET ( ...

  18. In Vitro and in Vivo Evaluation of Mutations in the NS Region of Lineage 2 West Nile Virus Associated with Neuroinvasiveness in a Mammalian Model

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    Katalin Szentpáli-Gavallér

    2016-02-01

    Full Text Available West Nile virus (WNV strains may differ significantly in neuroinvasiveness in vertebrate hosts. In contrast to genetic lineage 1 WNVs, molecular determinants of pathogenic lineage 2 strains have not been experimentally confirmed so far. A full-length infectious clone of a neurovirulent WNV lineage 2 strain (578/10; Central Europe was generated and amino acid substitutions that have been shown to attenuate lineage 1 WNVs were introduced into the nonstructural proteins (NS1 (P250L, NS2A (A30P, NS3 (P249H NS4B (P38G, C102S, E249G. The mouse neuroinvasive phenotype of each mutant virus was examined following intraperitoneal inoculation of C57BL/6 mice. Only the NS1-P250L mutation was associated with a significant attenuation of virulence in mice compared to the wild-type. Multiplication kinetics in cell culture revealed significantly lower infectious virus titres for the NS1 mutant compared to the wild-type, as well as significantly lower amounts of positive and negative stranded RNA.

  19. Visual detection of West Nile virus using reverse transcription loop-mediated isothermal amplification combined with a vertical flow visualization strip

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    Zengguo eCao

    2016-04-01

    Full Text Available West Nile virus (WNV causes a severe zoonosis, which can lead to a large number of casualties and considerable economic losses. A rapid and accurate identification methodfor WNV for use in field laboratories is urgently needed. Here, a method utilizing reverse transcription loop-mediated isothermal amplification combined with a vertical flow visualization strip (RT-LAMP-VF was developed to detect the envelope (E gene of WNV. The RT-LAMP-VF assay could detect 102 copies/μl ofan WNV RNA standard using a 40 min amplification reaction followed by a 2 min incubationof the amplification product on the visualization strip, and no cross-reaction with other closely related members of theFlavivirus genus was observed. The assay was further evaluated using cells and mouse brain tissues infected with a recombinant rabies virus expressing the E protein of WNV.The assay produced sensitivities of 101.5TCID50/ml and 101.33 TCID50/ml for detection of the recombinant virus in the cells and brain tissues, respectively. Overall, the RT-LAMP-VF assay developed in this study is rapid, simple and effective, and it is therefore suitable for clinical application in the field.

  20. In Vitro and in Vivo Evaluation of Mutations in the NS Region of Lineage 2 West Nile Virus Associated with Neuroinvasiveness in a Mammalian Model.

    Science.gov (United States)

    Szentpáli-Gavallér, Katalin; Lim, Stephanie M; Dencső, László; Bányai, Krisztián; Koraka, Penelope; Osterhaus, Albert D M E; Martina, Byron E E; Bakonyi, Tamás; Bálint, Ádám

    2016-02-19

    West Nile virus (WNV) strains may differ significantly in neuroinvasiveness in vertebrate hosts. In contrast to genetic lineage 1 WNVs, molecular determinants of pathogenic lineage 2 strains have not been experimentally confirmed so far. A full-length infectious clone of a neurovirulent WNV lineage 2 strain (578/10; Central Europe) was generated and amino acid substitutions that have been shown to attenuate lineage 1 WNVs were introduced into the nonstructural proteins (NS1 (P250L), NS2A (A30P), NS3 (P249H) NS4B (P38G, C102S, E249G)). The mouse neuroinvasive phenotype of each mutant virus was examined following intraperitoneal inoculation of C57BL/6 mice. Only the NS1-P250L mutation was associated with a significant attenuation of virulence in mice compared to the wild-type. Multiplication kinetics in cell culture revealed significantly lower infectious virus titres for the NS1 mutant compared to the wild-type, as well as significantly lower amounts of positive and negative stranded RNA.

  1. Replication potential and different modes of transmission of West Nile virus in an Indian strain of Culex gelidus Theobald (Diptera: Culicidae mosquitoes

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    A.B. Sudeep

    2014-12-01

    Full Text Available Background & objectives: Culex gelidus mosquito, an important vector of Japanese encephalitis virus, has shown to transmit West Nile virus (WNV, Kunjin and Murray Valley encephalitis viruses experimentally. An attempt was, therefore, made to study the replication kinetics and vector competence of an Indian strain of Cx. gelidus to WNV. Methods: Mosquitoes were infected by both intrathoracic inoculation and oral feeding and studied the growth kinetics by determining the virus titre on different days post-infection (PI. Vector competence was studied by determining the presence of WNV in saliva on subsequent days PI. Horizontal transmission was determined by demonstrating infection in infant mice by bite of mosquitoes that were fed on viraemic mice previously. Vertical transmission was studied by screening progeny derived from infected mosquitoes. Trans-stadial transmission was determined by screening adult mosquitoes emerged from parenterally inoculated IV instar larvae. Results: The mosquito replicated WNV to 7log10 TCID50/ml on Day 8 PI and maintained the titre for 14 days. Virus dissemination to legs and salivary glands could be detected, but not to ovaries up to Day 10 PI. The mosquitoes picked up infection from viraemic blood and transmitted successfully to infant mice on subsequent feeding. Trans-stadial transmission also could be demonstrated. However, vertical transmission could not be demonstrated. Interpretation & conclusion: The replication potential, maintenance of WNV for prolonged periods and ability to transmit WNV experimentally makes the mosquito a serious threat to public health especially in the wake of active WNV activity in certain parts of India.

  2. West Nile alternative open reading frame (N-NS4B/WARF4 is produced in infected West Nile Virus (WNV cells and induces humoral response in WNV infected individuals

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    Faggioni Giovanni

    2012-11-01

    Full Text Available Abstract Background West Nile Virus (WNV is a flavivirus that requires an efficient humoral and cellular host response for the control of neuroinvasive infection. We previously reported the existence of six alternative open reading frame proteins in WNV genome, one of which entitled WARF4 is exclusively restricted to the lineage I of the virus. WARF4 is able to elicit antibodies in WNV infected horses; however, there was no direct experimental proof of the existence of this novel protein. The purpose of this study was to demonstrate the in vitro production of WARF4 protein following WNV infection of cultured VERO cells and its immunity in WNV infected individuals. Results We produced a monoclonal antibody against WARF4 protein (MAb 3A12 which detected the novel protein in WNV lineage I-infected, cultured VERO cells while it did not react with WNV lineage II infected cells. MAb 3A12 specificity to WARF4 protein was confirmed by its reactivity to only one peptide among four analyzed that cover the full WARF4 amino acids sequence. In addition, WARF4 protein was expressed in the late phase of WNV lineage I infection. Western blotting and bioinformatics analyses strongly suggest that the protein could be translated by programmed −1 ribosomal frameshifting process. Since WARF4 is embedded in the NS4B gene, we rename this novel protein N-NS4B/WARF4. Furthermore, serological analysis shows that N-NS4B/WARF4 is able to elicit antibodies in WNV infected individuals. Conclusions N-NS4B/WARF4 is the second Alternative Reading Frame (ARF protein that has been demonstrated to be produced following WNV infection and might represent a novel tool for a better characterization of immune response in WNV infected individuals. Further serological as well as functional studies are required to characterize the function of the N-NS4B/WARF4 protein. Since the virus might actually make an extensive use of ARFs, it appears important to investigate the novel six ARF

  3. Advances in Research of West Nile Virus%西尼罗病毒研究进展

    Institute of Scientific and Technical Information of China (English)

    刘卫滨; 梁国栋

    2004-01-01

    西尼罗病毒(West Nile virus,WNV)首先在1937年乌干达的西尼罗地区的Omogo镇的一位发热病人血液中分离到,从而得名。西尼罗病毒属于黄病毒科黄病毒属。黄病毒科病毒共有70余种成员组成,其中黄病毒属大多属于经蚊虫、蜱等媒介传播的虫媒病毒(Arbovirus,Arthropod-borne-

  4. Rapid GIS-based profiling of West Nile virus transmission: defining environmental factors associated with an urbansuburban outbreak in Northeast Ohio, USA

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    A. Desiree LaBeaud

    2008-05-01

    Full Text Available Human West Nile virus (WNV infection was first detected in Cuyahoga county, Ohio, USA, in 2002. During that year’s extensive epidemic/epizootic among non-immune human and bird populations, the county experienced 155 cases of severe human West Nile neurological disease (WNND, incidence = 11.1 cases/100,000, with 11 fatalities. Structured serosurveys indicated that 1.9%, or ~ 26,000 of county residents (population = 1,372,303 were infected that year. In early 2003, in order to better focus monitoring and control efforts, we used a geographical information system (GIS approach and spatial statistical analysis to identify the association of environmental factors and human population structure with the observed local risk for WNV transmission. Within the varied range of urban/suburban/ rural habitats across the 1186 km2 county, exploratory analysis indicated significant clustering of WNND risk in inner-ring suburbs. Subsequent discriminant factor analysis based on inputs of census and land-use/land cover data was found to effectively classify sub-areas of the county having low, medium and high WNV risk. On a 1036 ha quadrat scale of resolution, higher risk of human infection was significantly associated with higher-income areas, increased fractionation of habitat and older housing, while it was negatively associated with areas of agricultural land, wetland or forest. The areal classification of WNV transmission risk has been validated over time through detection of increased local Culex spp. mosquito density (2002-2006, and increased frequency of WNV positive mosquito pools within the medium- and high-risk quadrats. This timely working identification of the transmission scale effectively focused control interventions against newly invasive WNV in a complex North American habitat.

  5. Dual inhibitors of the dengue and West Nile virus NS2B-NS3 proteases: Synthesis, biological evaluation and docking studies of novel peptide-hybrids.

    Science.gov (United States)

    Bastos Lima, Allan; Behnam, Mira A M; El Sherif, Yasmin; Nitsche, Christoph; Vechi, Sergio M; Klein, Christian D

    2015-09-01

    Dengue virus (DENV) and West Nile virus (WNV) are mosquito-borne arboviruses responsible for causing acute systemic diseases and severe health conditions in humans. The discovery of therapies capable to prevent infections or treat infected individuals remains an important challenge, since no vaccine or specific efficient treatment could be developed so far. In this context, we present herein the synthesis, characterization, biological evaluation and docking studies of novel peptide-hybrids based on 2,4-thiazolidinedione scaffolds containing non-polar groups. The most promising compound has an IC50 of 0.75 μM against WNV protease, which represents a seventyfold improvement in activity compared to our previously reported compounds. Experimental results and docking studies are in agreement with the hypothesis that a non-polar group in the scaffold is important to obtain interactions between the inhibitors and a hydrophobic pocket in the substrate recognition region of the DENV and WNV NS2B-NS3 serine proteases. PMID:26233795

  6. Structural and Functional Characterization of Programmed Ribosomal Frameshift Signals in West Nile Virus Strains Reveals High Structural Plasticity Among cis-Acting RNA Elements.

    Science.gov (United States)

    Moomau, Christine; Musalgaonkar, Sharmishtha; Khan, Yousuf A; Jones, John E; Dinman, Jonathan D

    2016-07-22

    West Nile virus (WNV) is a prototypical emerging virus for which no effective therapeutics currently exist. WNV uses programmed -1 ribosomal frameshifting (-1 PRF) to synthesize the NS1' protein, a C terminally extended version of its non-structural protein 1, the expression of which enhances neuro-invasiveness and viral RNA abundance. Here, the NS1' frameshift signals derived from four WNV strains were investigated to better understand -1 PRF in this quasispecies. Sequences previously predicted to promote -1 PRF strongly promote this activity, but frameshifting was significantly more efficient upon inclusion of additional 3' sequence information. The observation of different rates of -1 PRF, and by inference differences in the expression of NS1', may account for the greater degrees of pathogenesis associated with specific WNV strains. Chemical modification and mutational analyses of the longer and shorter forms of the -1 PRF signals suggests dynamic structural rearrangements between tandem stem-loop and mRNA pseudoknot structures in two of the strains. A model is suggested in which this is employed as a molecular switch to fine tune the relative expression of structural to non-structural proteins during different phases of the viral replication cycle. PMID:27226636

  7. Utilizing hunter harvest effort to survey for wildlife disease: a case study of West Nile virus in greater sage-grouse

    Science.gov (United States)

    Dusek, Robert J.; Hagen, Christian A.; Franson, J. Christian; Budeau, David A.; Hofmeister, Erik K.

    2014-01-01

    Greater sage-grouse (Centrocercus urophasianus; sage-grouse) are highly susceptible to infection with West Nile virus (WNV), with substantial mortality reported in wild populations and in experimentally infected birds. Although sage-grouse are hunted throughout much of their range, they have also recently been considered for protection under the Endangered Species Act. We used blood samples collected on filter-paper strips during the 2006–2010 Oregon, USA, annual sage-grouse hunt to survey for specific WNV-neutralizing antibodies that indicate a previous infection with WNV. During this period, hunters submitted 1,880 blood samples from sage-grouse they harvested. Samples obtained were proportional for all 12 Oregon sage-grouse hunting units. Laboratory testing of 1,839 samples by the WNV epitope-blocking enzyme-linked immunosorbent assay (bELISA) followed by plaque reduction neutralization test on bELISA-positive samples yielded 19 (1%) and 1 (0.05%) positive samples, respectively. These data provided early baseline information for future comparisons regarding the prevalence of WNV-specific neutralizing antibodies in sage-grouse in Oregon. This methodology may provide other states where sage-grouse (or other species) populations are hunted and where WNV constitutes a species conservation concern with a viable option to track the relative prevalence of the virus in populations.

  8. Climate Change Influences on the Global Potential Distribution of the Mosquito Culex quinquefasciatus, Vector of West Nile Virus and Lymphatic Filariasis

    Science.gov (United States)

    Elaagip, Arwa H.; Kenawy, Mohamed A.; Ayres, Constância F. J.; Peterson, A. Townsend; Soliman, Doaa E.

    2016-01-01

    Rapid emergence of most vector-borne diseases (VBDs) may be associated with range expansion of vector populations. Culex quinquefasciatus Say 1823 is a potential vector of West Nile virus, Saint Louis encephalitis virus, and lymphatic filariasis. We estimated the potential distribution of Cx. quinquefasciatus under both current and future climate conditions. The present potential distribution of Cx. quinquefasciatus showed high suitability across low-latitude parts of the world, reflecting the current distribution of the species. Suitable conditions were identified also in narrow zones of North Africa and Western Europe. Model transfers to future conditions showed a potential distribution similar to that under present-day conditions, although with higher suitability in southern Australia. Highest stability with changing climate was between 30°S and 30°N. The areas present high agreement among diverse climate models as regards distributional potential in the future, but differed in anticipating potential for distribution in North and Central Africa, southern Asia, central USA, and southeastern Europe. Highest disparity in model predictions across representative concentration pathways (RCPs) was in Saudi Arabia and Europe. The model predictions allow anticipation of changing distributional potential of the species in coming decades. PMID:27695107

  9. Proximity of Residence to Bodies of Water and Risk for West Nile Virus Infection: A Case-Control Study in Houston, Texas

    Directory of Open Access Journals (Sweden)

    Melissa S. Nolan

    2012-01-01

    Full Text Available West Nile virus (WNV, a mosquito-borne virus, has clinically affected hundreds of residents in the Houston metropolitan area since its introduction in 2002. This study aimed to determine if living within close proximity to a water source increases one’s odds of infection with WNV. We identified 356 eligible WNV-positive cases and 356 controls using a population proportionate to size model with US Census Bureau data. We found that living near slow moving water sources was statistically associated with increased odds for human infection, while living near moderate moving water systems was associated with decreased odds for human infection. Living near bayous lined with vegetation as opposed to concrete also showed increased risk of infection. The habitats of slow moving and vegetation lined water sources appear to favor the mosquito-human transmission cycle. These methods can be used by resource-limited health entities to identify high-risk areas for arboviral disease surveillance and efficient mosquito management initiatives.

  10. A Brief Report of West Nile Virus Neuroinvasive Disease in the Summer of 2012 in Hamilton, Ontario

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    Lei Jiao

    2014-01-01

    Full Text Available West Nile neuroinvasive disease is a severe infectious disease that is associated with a high mortality rate, especially in immunocompromised hosts. Physicians who are aware of its clinical presentations may be able to order diagnostic tests more appropriately and avoid inappropriate treatment. In the present series, the cases of seven patients admitted to Hamilton Health Sciences (Hamilton, Ontario in the summer of 2012 with a diagnosis of West Nile neuroinvasive disease were retrospectively reviewed based on available medical records. According to the clinical and laboratory criteria published by the Centers for Disease Control and Prevention, five cases were diagnosed as encephalitis, one case as meningitis and one case as meningomyelitis. Patients were managed supportively. Forty-three percent (three of seven presented with rash, 71% (five of seven did not report headache despite exhibiting neurological symptoms, 43% (three of seven did not have fever on presentation and 37.5% of cerebrospinal fluid samples exhibited a neutrophil predominance. The mortality rate in the present series was 14.3% (one of seven, and 57.1% (four of seven of the patients had residual symptoms on discharge and at follow-up.

  11. Identification and characterization of a virus-specific continuous B-cell epitope on the PrM/M protein of Japanese Encephalitis Virus: potential application in the detection of antibodies to distinguish Japanese Encephalitis Virus infection from West Nile Virus and Dengue Virus infections

    Directory of Open Access Journals (Sweden)

    Liu Wen-Xin

    2010-09-01

    Full Text Available Abstract Background Differential diagnose of Japanese encephalitis virus (JEV infection from other flavivirus especially West Nile virus (WNV and Dengue virus (DV infection was greatly hindered for the serological cross-reactive. Virus specific epitopes could benefit for developing JEV specific antibodies detection methods. To identify the JEV specific epitopes, we fully mapped and characterized the continuous B-cell epitope of the PrM/M protein of JEV. Results To map the epitopes on the PrM/M protein, we designed a set of 20 partially overlapping fragments spanning the whole PrM, fused them with GST, and expressed them in an expression vector. Linear epitope M14 (105VNKKEAWLDSTKATRY120 was detected by enzyme-linked immunosorbent assay (ELISA. By removing amino acid residues individually from the carboxy and amino terminal of peptide M14, we confirmed that the minimal unit of the linear epitope of PrM/M was M14-13 (108KEAWLDSTKAT118. This epitope was highly conserved across different JEV strains. Moreover, this epitope did not cross-react with WNV-positive and DENV-positive sera. Conclusion Epitope M14-13 was a JEV specific lineal B-cell epitpe. The results may provide a useful basis for the development of epitope-based virus specific diagnostic clinical techniques.

  12. Host group formation decreases exposure to vector-borne disease: a field experiment in a 'hotspot' of West Nile virus transmission.

    Science.gov (United States)

    Krebs, Bethany L; Anderson, Tavis K; Goldberg, Tony L; Hamer, Gabriel L; Kitron, Uriel D; Newman, Christina M; Ruiz, Marilyn O; Walker, Edward D; Brawn, Jeffrey D

    2014-12-01

    Animals can decrease their individual risk of predation by forming groups. The encounter-dilution hypothesis extends the potential benefits of gregariousness to biting insects and vector-borne disease by predicting that the per capita number of insect bites should decrease within larger host groups. Although vector-borne diseases are common and can exert strong selective pressures on hosts, there have been few tests of the encounter-dilution effect in natural systems. We conducted an experimental test of the encounter-dilution hypothesis using the American robin (Turdus migratorius), a common host species for the West Nile virus (WNV), a mosquito-borne pathogen. By using sentinel hosts (house sparrows, Passer domesticus) caged in naturally occurring communal roosts in the suburbs of Chicago, we assessed sentinel host risk of WNV exposure inside and outside of roosts. We also estimated per capita host exposure to infected vectors inside roosts and outside of roosts. Sentinel birds caged inside roosts seroconverted to WNV more slowly than those outside of roosts, suggesting that social groups decrease per capita exposure to infected mosquitoes. These results therefore support the encounter-dilution hypothesis in a vector-borne disease system. Our results suggest that disease-related selective pressures on sociality may depend on the mode of disease transmission. PMID:25339722

  13. Susceptibility and antibody response of Vesper Sparrows (Pooecetes gramineus) to West Nile virus: A potential amplification host in sagebrush-grassland habitat

    Science.gov (United States)

    Hofmeister, Erik K.; Dusek, Robert J.; Fassbinder-Orth, Carol; Owen, Benjamin; Franson, J. Christian

    2016-01-01

    West Nile virus (WNV) spread to the US western plains states in 2003, when a significant mortality event attributed to WNV occurred in Greater Sage-grouse ( Centrocercus urophasianus ). The role of avian species inhabiting sagebrush in the amplification of WNV in arid and semiarid regions of the North America is unknown. We conducted an experimental WNV challenge study in Vesper Sparrows ( Pooecetes gramineus ), a species common to sagebrush and grassland habitats found throughout much of North America. We found Vesper Sparrows to be moderately susceptible to WNV, developing viremia considered sufficient to transmit WNV to feeding mosquitoes, but the majority of birds were capable of surviving infection and developing a humoral immune response to the WNV nonstructural 1 and envelope proteins. Despite clearance of viremia, after 6 mo, WNV was detected molecularly in three birds and cultured from one bird. Surviving Vesper Sparrows were resistant to reinfection 6 mo after the initial challenge. Vesper sparrows could play a role in the amplification of WNV in sagebrush habitat and other areas of their range, but rapid clearance of WNV may limit their importance as competent amplification hosts of WNV.

  14. Survival analysis, long-term outcomes, and percentage of recovery up to 8 years post-infection among the Houston West Nile virus cohort.

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    Kristy O Murray

    Full Text Available In 2012, we witnessed a resurgence of West Nile virus (WNV in the United States, with the largest outbreak of human cases reported since 2003. WNV is now endemic and will continue to produce epidemics over time, therefore defining the long-term consequences of WNV infection is critical. Over a period of eight years, we prospectively followed a cohort of 157 WNV-infected subjects in the Houston metropolitan area to observe recovery over time and define the long-term clinical outcomes. We used survival analysis techniques to determine percentage of recovery over time and the effects of demographic and co-morbid conditions on recovery. We found that 40% of study participants continued to experience symptoms related to their WNV infection up to 8 years later. Having a clinical presentation of encephalitis and being over age 50 were significantly associated with prolonged or poor recovery over time. Since the health and economic impact as a result of prolonged recovery, continued morbidity, and related disability is likely substantial in those infected with WNV, future research should be aimed at developing effective vaccines to prevent illness and novel therapeutics to minimize morbidity, mortality, and long-term complications from infection.

  15. Pathogenicity of two recent Western Mediterranean West Nile virus isolates in a wild bird species indigenous to Southern Europe: the red-legged partridge.

    Science.gov (United States)

    Sotelo, Elena; Gutierrez-Guzmán, Ana Valeria; del Amo, Javier; Llorente, Francisco; El-Harrak, Mehdi; Pérez-Ramírez, Elisa; Blanco, Juan Manuel; Höfle, Ursula; Jiménez-Clavero, Miguel Angel

    2011-01-01

    West Nile virus (WNV) is an emerging zoonotic pathogen whose geographic spread and incidence in humans, horses and birds has increased significantly in recent years. WNV has long been considered a mild pathogen causing self-limiting outbreaks. This notion has changed as WNV is causing large epidemics with a high impact on human and animal health. This has been particularly noteworthy since its introduction into North America in 1999. There, native bird species have been shown to be highly susceptible to WNV infection and disease with high mortalities. For this reason, the effect of WNV infection in North American bird species has been thoroughly studied by means of experimental inoculations in controlled trials. To a lesser extent, European wild birds have been shown to be affected clinically by WNV infection. Yet experimental studies on European wild bird species are lacking. The red-legged partridge (Alectoris rufa) is a gallinaceous bird indigenous to the Iberian Peninsula, widely distributed in South Western Europe. It plays a key role in the Mediterranean ecosystem and constitutes an economically important game species. As such it is raised intensively in outdoor facilities. In this work, red-legged partridges were experimentally infected with two recent WNV isolates from the Western Mediterranean area: Morocco/2003 and Spain/2007. All inoculated birds became viremic and showed clinical disease, with mortality rates of 70% and 30%, respectively. These results show that Western Mediterranean WNV variants can be pathogenic for some European bird species, such as the red-legged partridge. PMID:21314967

  16. A dietary risk assessment of the pyrethroid insecticide resmethrin associated with its use for West Nile Virus mosquito vector control in California

    Directory of Open Access Journals (Sweden)

    Wesley C. Carr

    2006-01-01

    Full Text Available An outbreak of human illnesses associated with West Nile Virus (WNV occurred in New York City in 1999. Since then, it has gradually spread westwards, reaching northern California for the first time in 2005. WNV is transmitted by several mosquito species and birds serve as the main reservoir. Several control measures have been used, targeting both the aquatic larvae and the adult mosquitoes. In the latter case, roosting birds in trees are sprayed with pyrethroid insecticides because these are highly toxic to mosquitoes, but have low avian toxicity. A request was made to use a resmethrin-containing insecticide during the month of October 2005 in California. Because resmethrin was not registered for use on growing crops, concerns were raised about potential crop contamination. Therefore, an expedited dietary risk assessment was conducted on resmethrin. Developmental toxicity in the rat (NOELs of 25 or 40 mg/kg/day was used as the acute endpoint and dietary exposure was assessed using the DEEM-FCIDTM computer program. Only crops growing above ground during October were considered. Margins of Safety (MOS were found to be above 100, the level generally considered to be sufficient to protect public health when using an animal NOEL.

  17. Activity Patterns of St. Louis Encephalitis and West Nile Viruses in Free Ranging Birds during a Human Encephalitis Outbreak in Argentina.

    Science.gov (United States)

    Diaz, Luis Adrián; Quaglia, Agustín Ignacio; Konigheim, Brenda Salomé; Boris, Analia Silvana; Aguilar, Juan Javier; Komar, Nicholas; Contigiani, Marta Silvia

    2016-01-01

    St. Louis encephalitis virus (SLEV) (Flavivirus) is a reemerging arbovirus in the southern cone of South America. In 2005, an outbreak of SLEV in central Argentina resulted in 47 human cases with 9 deaths. In Argentina, the ecology of SLEV is poorly understood. Because certain birds are the primary amplifiers in North America, we hypothesized that birds amplify SLEV in Argentina as well. We compared avian SLEV seroprevalence in a variety of ecosystems in and around Córdoba city from 2004 (before the epidemic) and 2005 (during the epidemic). We also explored spatial patterns to better understand the local ecology of SLEV transmission. Because West Nile virus (WNV) was also detected in Argentina in 2005, all analyses were also conducted for WNV. A total of 980 birds were sampled for detection of SLEV and WNV neutralizing antibodies. SLEV seroprevalence in birds increased 11-fold from 2004 to 2005. Our study demonstrated that a high proportion (99.3%) of local birds were susceptible to SLEV infection immediately prior to the 2005 outbreak, indicating that the vertebrate host population was primed to amplify SLEV. SLEV was found distributed in a variety of environments throughout the city of Córdoba. However, the force of viral transmission varied among sites. Fine scale differences in populations of vectors and vertebrate hosts would explain this variation. In summary, we showed that in 2005, both SLEV and to a lesser extent WNV circulated in the avian population. Eared Dove, Picui Ground-Dove and Great Kiskadee are strong candidates to amplify SLEV because of their exposure to the pathogen at the population level, and their widespread abundance. For the same reasons, Rufous Hornero may be an important maintenance host for WNV in central Argentina. Competence studies and vector feeding studies are needed to confirm these relationships. PMID:27564679

  18. Activity Patterns of St. Louis Encephalitis and West Nile Viruses in Free Ranging Birds during a Human Encephalitis Outbreak in Argentina

    Science.gov (United States)

    Quaglia, Agustín Ignacio; Konigheim, Brenda Salomé; Boris, Analia Silvana; Aguilar, Juan Javier; Komar, Nicholas; Contigiani, Marta Silvia

    2016-01-01

    St. Louis encephalitis virus (SLEV) (Flavivirus) is a reemerging arbovirus in the southern cone of South America. In 2005, an outbreak of SLEV in central Argentina resulted in 47 human cases with 9 deaths. In Argentina, the ecology of SLEV is poorly understood. Because certain birds are the primary amplifiers in North America, we hypothesized that birds amplify SLEV in Argentina as well. We compared avian SLEV seroprevalence in a variety of ecosystems in and around Córdoba city from 2004 (before the epidemic) and 2005 (during the epidemic). We also explored spatial patterns to better understand the local ecology of SLEV transmission. Because West Nile virus (WNV) was also detected in Argentina in 2005, all analyses were also conducted for WNV. A total of 980 birds were sampled for detection of SLEV and WNV neutralizing antibodies. SLEV seroprevalence in birds increased 11-fold from 2004 to 2005. Our study demonstrated that a high proportion (99.3%) of local birds were susceptible to SLEV infection immediately prior to the 2005 outbreak, indicating that the vertebrate host population was primed to amplify SLEV. SLEV was found distributed in a variety of environments throughout the city of Córdoba. However, the force of viral transmission varied among sites. Fine scale differences in populations of vectors and vertebrate hosts would explain this variation. In summary, we showed that in 2005, both SLEV and to a lesser extent WNV circulated in the avian population. Eared Dove, Picui Ground-Dove and Great Kiskadee are strong candidates to amplify SLEV because of their exposure to the pathogen at the population level, and their widespread abundance. For the same reasons, Rufous Hornero may be an important maintenance host for WNV in central Argentina. Competence studies and vector feeding studies are needed to confirm these relationships. PMID:27564679

  19. Towards the conservation of endangered avian species: a recombinant West Nile Virus vaccine results in increased humoral and cellular immune responses in Japanese Quail (Coturnix japonica.

    Directory of Open Access Journals (Sweden)

    Jay A Young

    Full Text Available West Nile Virus (WNV arrived in North America in 1999 and is now endemic. Many families of birds, especially corvids, are highly susceptible to WNV and infection often results in fatality. Avian species susceptible to WNV infection also include endangered species, such as the Greater Sage-Grouse (Centrocercus uropbasianuts and the Eastern Loggerhead Shrike (Lanius ludovicianus migrans. The virus has been shown to contribute towards the likelihood of their extinction. Although a clear and present threat, there exists no avian WNV vaccine available to combat this lethal menace. As a first step in establishing an avian model for testing candidate WNV vaccines, avian antibody based reagents were assessed for cross-reactivity with Japanese quail (Coturnix japonica T cell markers CD4 and CD8; the most reactive were found to be the anti-duck CD8 antibody, clone Du-CD8-1, and the anti-chicken/turkey CD4 antibody, clone CT4. These reagents were then used to assess vaccine performance as well as to establish T cell populations in quail, with a novel population of CD4/CD8 double positive T cells being identified in Japanese quail. Concurrently, non-replicating recombinant adenoviruses, expressing either the WNV envelope or NS3 'genes' were constructed and assessed for effectiveness as avian vaccines. Japanese Quail were selected for testing the vaccines, as they provide an avian model that parallels the population diversity of bird species in the wild. Both the level of WNV specific antibodies and the number of T cells in vaccinated birds were increased compared to unvaccinated controls. The results indicate the vaccines to be effective in increasing both humoral and cellular immune responses. These recombinant vaccines therefore may find utility as tools to protect and maintain domestic and wild avian populations. Their implementation may also arrest the progression towards extinction of endangered avian species and reduce the viral reservoir that

  20. Locating suitable habitats for West Nile Virus-infected mosquitoes through association of environmental characteristics with infected mosquito locations: a case study in Shelby County, Tennessee

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    Bialkowska-Jelinska Elzbieta

    2008-03-01

    Full Text Available Abstract Background Since its first detection in 2001, West Nile Virus (WNV poses a significant health risk for residents of Shelby County in Tennessee. This situation forced public health officials to adopt efficient methods for monitoring disease spread and predicting future outbreaks. Analyses that use environmental variables to find suitable habitats for WNV-infected mosquitoes have the potential to support these efforts. Using the Mahalanobis Distance statistic, we identified areas of Shelby County that are ecologically most suitable for sustaining WNV, based on similarity of environmental characteristics to areas where WNV was found. The environmental characteristics in this study were based on Geographic Information Systems (GIS data, such as elevation, slope, land use, vegetation density, temperature, and precipitation. Results Our analyses produced maps of likely habitats of WNV-infected mosquitoes for each week of August 2004, revealing the areas that are ecologically most suitable for sustaining WNV within the core of the Memphis urban area. By comparing neighbourhood social characteristics to the environmental factors that contribute to WNV infection, potential social drivers of WNV transmission were revealed in Shelby County. Results show that human population characteristics and housing conditions such as a high percentage of black population, low income, high rental occupation, old structures, and vacant housing are associated with the focal area of WNV identified for each week of the study period. Conclusion We demonstrated that use of the Mahalanobis Distance statistic as a similarity index to assess environmental characteristics is a potential raster-based approach to identify areas ecologically most suitable for sustaining the virus. This approach was also useful to monitor changes over time for likely locations of infected mosquito habitats. This technique is very helpful for authorities when making decisions related to an

  1. Epidemics of the central nervous system infections caused by West Nile virus in the territory of the South Bačka District, Vojvodina, Serbia

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    Sević Siniša

    2015-01-01

    Full Text Available Background/Aim. West Nile virus (WNV is a neurotropic RNA virus particle which belongs to the Flaviviridae family, genus Flavivirus. It is sustained in arthropods within the transmission cycle between the mosquitoes and birds. Most commonly (80% of cases WNV infections are asymptomatic among people. Less than 1% of patients develop neuroinvasive forms of the disease - meningitis, encephalitis, or acute flaccid paralysis. The aim of the research is to determine most common clinical and laboratory manifestations, to emphazise the presence of comorbidities and outcomes of treatment among patients with WNV infection. Methods. This retrospective study, which was conducted in the period from January 1, 2012 to December 31, 2013, evaluated 32 patients who were diagnosed with WNV infection based on clinical findings, laboratory, and serological tests. To assess statistical significance we used χ2, and t-test. Results. The study involved 22 (69% males and 10 (31% females aged from 31 to 65 years. On admission, there were 16 (50% febrile individuals, 27 (84.4% with positive meningeal signs, 17 (53.2% with pathological neurological signs, and 10 (31.3% with consciousness disorders. WNV infection was confirmed by the method enzyme linked immuno sorbent assay (ELISA in all the patients, while Reverse Transcription Polymerase Chain Reaction (RT-PCR test was positive in 3 (30% of the tested patients. Cardiovascular comorbidities dominated in 7 (21.9% of the cases. Full recovery was accomplished in 87.5 % of the cases. Conclusion. The results of our study show that the absence of meningeal signs and fever on the day 7 of hospital treatment are indicators of good course and prognosis of neuroinvasive forms of WNV infection. Comorbidities do not increase the risk of disease. ELISA test is a sovereign diagnostic method. In most cases, after the administered symptomatic therapy, the complete recovery of patients was achieved. [Projekat Ministarstva nauke Republike

  2. The evolution of virulence of West Nile virus in a mosquito vector: implications for arbovirus adaptation and evolution

    OpenAIRE

    Alexander T. Ciota; Ehrbar, Dylan J.; MATACCHIERO, AMY C.; Van Slyke, Greta A; Kramer, Laura D.

    2013-01-01

    Background Virulence is often coupled with replicative fitness of viruses in vertebrate systems, yet the relationship between virulence and fitness of arthropod-borne viruses (arboviruses) in invertebrates has not been evaluated. Although the interactions between vector-borne pathogens and their invertebrate hosts have been characterized as being largely benign, some costs of arbovirus exposure have been identified for mosquitoes. The extent to which these costs may be strain-specific and the...

  3. Detection of West Nile virus by real-time RT-PCR%实时荧光PCR检测西尼罗病毒方法的建立

    Institute of Scientific and Technical Information of China (English)

    邱璐; 李小林; 蒋静; 王艳; 周小俊

    2012-01-01

    西尼罗病毒可引起人畜共患虫媒病,已经在全球许多国家流行.主要随迁飞的鸟类携带扩散,传入我国的风险很大.本研究在参考多株西尼罗病毒基因序列的基础上,设计引物及探针,建立了实时荧光RT-PCR的方法.特异性试验表明,该方法对同为黄病毒科的日本脑炎病毒(JEV) SA14-14-2株和登革病毒(DEN)Ⅰ型cDNA检测均为阴性;敏感性试验证实,实时RT-PCR检测敏感度要比常规RT-PCR法高100倍.说明本研究建立的实时RT-PCR方法敏感性和特异性均较高,可用于西尼罗病毒感染的早期监测和诊断.%West Nile virus ( WNV) is by far the most widely distributed arbovirus. The WNV infection has been recognized as an emerging infectious disease with possible transmitting risk in our country. The pairs of primers and TaqMan probes were designed and synthesized based on the nucleotide sequences of WNV in GenBank. After optimization, the real-time PCR was established. These primers were applied to detect the nucleic acids of WNV, Japanese B encephalitis virus (JEV) and Dengue viruses (DEN) , and the latter two viruses could not be detected. Compared with conventional RT-PCR, real-time PCR appeared to be approximately 100 times more sensitive in detection of WNV. It suggests that the real-time PCR developed for the detection of WNV shows high degree of specificity and sensitivity, and can be used for WNV inspection and investigation.

  4. Identification of two linear B-cell epitopes from West Nile virus NS1 by screening a phage-displayed random peptide library

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    Qin Yong-Li

    2011-07-01

    Full Text Available Abstract Background The West Nile virus (WNV nonstructural protein 1 (NS1 is an important antigenic protein that elicits protective antibody responses in animals and can be used for the serological diagnosis of WNV infection. Although previous work has demonstrated the vital role of WNV NS1-specific antibody responses, the specific epitopes in the NS1 have not been identified. Results The present study describes the identification of two linear B-cell epitopes in WNV NS1 through screening a phage-displayed random 12-mer peptide library with two monoclonal antibodies (mAbs 3C7 and 4D1 that directed against the NS1. The mAbs 3C7 and 4D1 recognized phages displaying peptides with the consensus motifs LTATTEK and VVDGPETKEC, respectively. Exact sequences of both motifs were found in the NS1 (895LTATTEK901 and 925VVDGPETKEC934. Further identification of the displayed B cell epitopes were conducted using a set of truncated peptides expressed as MBP fusion proteins. The data indicated that 896TATTEK901 and925VVDGPETKEC934 are minimal determinants of the linear B cell epitopes recognized by the mAbs 3C7 and 4D1, respectively. Antibodies present in the serum of WNV-positive horses recognized the minimal linear epitopes in Western blot analysis, indicating that the two peptides are antigenic in horses during infection. Furthermore, we found that the epitope recognized by 3C7 is conserved only among WNV strains, whereas the epitope recognized by 4D1 is a common motif shared among WNV and other members of Japanese encephalitis virus (JEV serocomplex. Conclusions We identified TATTEK and VVDGPETKEC as NS1-specific linear B-cell epitopes recognized by the mAbs 3C7 and 4D1, respectively. The knowledge and reagents generated in this study may have potential applications in differential diagnosis and the development of epitope-based marker vaccines against WNV and other viruses of JEV serocomplex.

  5. Virus del Nilo Occidental: Lo que debe saber - Agosto de 2012 (West Nile Virus: What You Need to Know Now - August 2012)

    Centers for Disease Control (CDC) Podcasts

    2012-08-21

    Este podcast nombra los estados en donde se han notificado la mayoría de casos del virus del Nilo Occidental y explica la manera en que las personas se pueden proteger contra ese virus.  Created: 8/21/2012 by .   Date Released: 8/22/2012.

  6. Efficacy of three vaccines in protecting Western Scrub-Jays (Aphelocoma californica) from experimental infection with West Nile virus: implications for vaccination of Island Scrub-Jays (Aphelocoma insularis).

    Science.gov (United States)

    Wheeler, Sarah S; Langevin, Stanley; Woods, Leslie; Carroll, Brian D; Vickers, Winston; Morrison, Scott A; Chang, Gwong-Jen J; Reisen, William K; Boyce, Walter M

    2011-08-01

    The devastating effect of West Nile virus (WNV) on the avifauna of North America has led zoo managers and conservationists to attempt to protect vulnerable species through vaccination. The Island Scrub-Jay (Aphelocoma insularis) is one such species, being a corvid with a highly restricted insular range. Herein, we used congeneric Western Scrub-Jays (Aphelocoma californica) to test the efficacy of three WNV vaccines in protecting jays from an experimental challenge with WNV: (1) the Fort Dodge West Nile-Innovator(®) DNA equine vaccine, (2) an experimental DNA plasmid vaccine, pCBWN, and (3) the Merial Recombitek(®) equine vaccine. Vaccine efficacy after challenge was compared with naïve and nonvaccinated positive controls and a group of naturally immune jays. Overall, vaccination lowered peak viremia compared with nonvaccinated positive controls, but some WNV-related pathology persisted and the viremia was sufficient to possibly infect susceptible vector mosquitoes. The Fort Dodge West Nile-Innovator DNA equine vaccine and the pCBWN vaccine provided humoral immune priming and limited side effects. Five of the six birds vaccinated with the Merial Recombitek vaccine, including a vaccinated, non-WNV challenged control, developed extensive necrotic lesions in the pectoral muscle at the vaccine inoculation sites, which were attributed to the Merial vaccine. In light of the well-documented devastating effects of high morbidity and mortality associated with WNV infection in corvids, vaccination of Island Scrub-Jays with either the Fort Dodge West Nile-Innovator DNA vaccine or the pCBWN vaccine may increase the numbers of birds that would survive an epizootic should WNV become established on Santa Cruz Island. PMID:21438693

  7. Immunization of mice with recombinant mosquito salivary protein D7 enhances mortality from subsequent West Nile virus infection via mosquito bite.

    Directory of Open Access Journals (Sweden)

    Krystle L Reagan

    Full Text Available BACKGROUND: Mosquito salivary proteins (MSPs modulate the host immune response, leading to enhancement of arboviral infections. Identification of proteins in saliva responsible for immunomodulation and counteracting their effects on host immune response is a potential strategy to protect against arboviral disease. We selected a member of the D7 protein family, which are among the most abundant and immunogenic in mosquito saliva, as a vaccine candidate with the aim of neutralizing effects on the mammalian immune response normally elicited by mosquito saliva components during arbovirus transmission. METHODOLOGY/PRINCIPAL FINDINGS: We identified D7 salivary proteins of Culex tarsalis, a West Nile virus (WNV vector in North America, and expressed 36 kDa recombinant D7 (rD7 protein for use as a vaccine. Vaccinated mice exhibited enhanced interferon-γ and decreased interleukin-10 expression after uninfected mosquito bite; however, we found unexpectedly that rD7 vaccination resulted in enhanced pathogenesis from mosquito-transmitted WNV infection. Passive transfer of vaccinated mice sera to naïve mice also resulted in increased mortality rates from subsequent mosquito-transmitted WNV infection, implicating the humoral immune response to the vaccine in enhancement of viral pathogenesis. Vaccinated mice showed decreases in interferon-γ and increases in splenocytes producing the regulatory cytokine IL-10 after WNV infection by mosquito bite. CONCLUSIONS/SIGNIFICANCE: Vector saliva vaccines have successfully protected against other blood-feeding arthropod-transmitted diseases. Nevertheless, the rD7 salivary protein vaccine was not a good candidate for protection against WNV disease since immunized mice infected via an infected mosquito bite exhibited enhanced mortality. Selection of salivary protein vaccines on the bases of abundance and immunogenicity does not predict efficacy.

  8. A Novel Synthetic TLR-4 Agonist Adjuvant Increases the Protective Response to a Clinical-Stage West Nile Virus Vaccine Antigen in Multiple Formulations.

    Science.gov (United States)

    Van Hoeven, Neal; Joshi, Sharvari Waghmare; Nana, Ghislain Ismael; Bosco-Lauth, Angela; Fox, Christopher; Bowen, Richard A; Clements, David E; Martyak, Timothy; Parks, D Elliot; Baldwin, Susan; Reed, Steven G; Coler, Rhea N

    2016-01-01

    West Nile virus (WNV) is a mosquito-transmitted member of the Flaviviridae family that has emerged in recent years to become a serious public health threat. Given the sporadic nature of WNV epidemics both temporally and geographically, there is an urgent need for a vaccine that can rapidly provide effective immunity. Protection from WNV infection is correlated with antibodies to the viral envelope (E) protein, which encodes receptor binding and fusion functions. Despite many promising E-protein vaccine candidates, there are currently none licensed for use in humans. This study investigates the ability to improve the immunogenicity and protective capacity of a promising clinical-stage WNV recombinant E-protein vaccine (WN-80E) by combining it with a novel synthetic TLR-4 agonist adjuvant. Using the murine model of WNV disease, we find that inclusion of a TLR-4 agonist in either a stable oil-in-water emulsion (SE) or aluminum hydroxide (Alum) formulation provides both dose and dosage sparing functions, whereby protection can be induced after a single immunization containing only 100 ng of WN-80E. Additionally, we find that inclusion of adjuvant with a single immunization reduced viral titers in sera to levels undetectable by viral plaque assay. The enhanced protection provided by adjuvanted immunization correlated with induction of a Th1 T-cell response and the resultant shaping of the IgG response. These findings suggest that inclusion of a next generation adjuvant may greatly enhance the protective capacity of WNV recombinant subunit vaccines, and establish a baseline for future development. PMID:26901122

  9. A Novel Synthetic TLR-4 Agonist Adjuvant Increases the Protective Response to a Clinical-Stage West Nile Virus Vaccine Antigen in Multiple Formulations.

    Directory of Open Access Journals (Sweden)

    Neal Van Hoeven

    Full Text Available West Nile virus (WNV is a mosquito-transmitted member of the Flaviviridae family that has emerged in recent years to become a serious public health threat. Given the sporadic nature of WNV epidemics both temporally and geographically, there is an urgent need for a vaccine that can rapidly provide effective immunity. Protection from WNV infection is correlated with antibodies to the viral envelope (E protein, which encodes receptor binding and fusion functions. Despite many promising E-protein vaccine candidates, there are currently none licensed for use in humans. This study investigates the ability to improve the immunogenicity and protective capacity of a promising clinical-stage WNV recombinant E-protein vaccine (WN-80E by combining it with a novel synthetic TLR-4 agonist adjuvant. Using the murine model of WNV disease, we find that inclusion of a TLR-4 agonist in either a stable oil-in-water emulsion (SE or aluminum hydroxide (Alum formulation provides both dose and dosage sparing functions, whereby protection can be induced after a single immunization containing only 100 ng of WN-80E. Additionally, we find that inclusion of adjuvant with a single immunization reduced viral titers in sera to levels undetectable by viral plaque assay. The enhanced protection provided by adjuvanted immunization correlated with induction of a Th1 T-cell response and the resultant shaping of the IgG response. These findings suggest that inclusion of a next generation adjuvant may greatly enhance the protective capacity of WNV recombinant subunit vaccines, and establish a baseline for future development.

  10. Geographic incidence of human West Nile virus in northern Virginia, USA, in relation to incidence in birds and variations in urban environment.

    Science.gov (United States)

    Liu, Hua; Weng, Qihao; Gaines, David

    2011-09-15

    Previous studies have analyzed the number and location of bird infections with human incidence of West Nile virus (WNV) as well as the effects of environmental and socioeconomic factors on WNV propagation. However, such associations require more quantitative analyses. This study is intended to quantitatively analyze the relationship in eight counties/independent cities in the northern Virginia, based on an integrated analysis of spatially explicit information on precipitation, land cover, infrastructure, and demographic data using Geographical Information Systems, remote sensing, and statistics. Results show that bird infections in years 2002-2003 were closely associated with low to medium level of impervious surface with certain percentage of canopy and precipitation. Environmental and socioeconomic factors such as percentages of impervious surface, canopy, senior population (65 and older), old houses, bird risk areas, and low-income population were important indicators of human WNV risk in 2002. Limited impervious surface with some canopy provides suitable habitats for WNV transmission, where bird-feeding mosquitoes can forage for blood meals from nesting/roosting birds. Certain socioeconomic conditions such as old houses were linked with human infections by providing favorable environmental conditions, i.e., mature trees with abundant canopy and settled storm sewer systems. It should be noted that the current results may be biased toward urban environments, where dead birds were more likely found, and because the sampling efforts for the bird mortality were rather based on local residents' reports than a designed random sampling method. This geospatial study contributes toward better targeting of WNV prevention within the study area. It also provides an example of how geospatial methods and variables may be used in understanding the ecology of human WNV risk for other areas. PMID:21802710

  11. Pathogenicity of two recent Western Mediterranean West Nile virus isolates in a wild bird species indigenous to Southern Europe: the red-legged partridge

    Directory of Open Access Journals (Sweden)

    Sotelo Elena

    2011-01-01

    Full Text Available Abstract West Nile virus (WNV is an emerging zoonotic pathogen whose geographic spread and incidence in humans, horses and birds has increased significantly in recent years. WNV has long been considered a mild pathogen causing self-limiting outbreaks. This notion has changed as WNV is causing large epidemics with a high impact on human and animal health. This has been particularly noteworthy since its introduction into North America in 1999. There, native bird species have been shown to be highly susceptible to WNV infection and disease with high mortalities. For this reason, the effect of WNV infection in North American bird species has been thoroughly studied by means of experimental inoculations in controlled trials. To a lesser extent, European wild birds have been shown to be affected clinically by WNV infection. Yet experimental studies on European wild bird species are lacking. The red-legged partridge (Alectoris rufa is a gallinaceous bird indigenous to the Iberian Peninsula, widely distributed in South Western Europe. It plays a key role in the Mediterranean ecosystem and constitutes an economically important game species. As such it is raised intensively in outdoor facilities. In this work, red-legged partridges were experimentally infected with two recent WNV isolates from the Western Mediterranean area: Morocco/2003 and Spain/2007. All inoculated birds became viremic and showed clinical disease, with mortality rates of 70% and 30%, respectively. These results show that Western Mediterranean WNV variants can be pathogenic for some European bird species, such as the red-legged partridge.

  12. A Novel Synthetic TLR-4 Agonist Adjuvant Increases the Protective Response to a Clinical-Stage West Nile Virus Vaccine Antigen in Multiple Formulations.

    Science.gov (United States)

    Van Hoeven, Neal; Joshi, Sharvari Waghmare; Nana, Ghislain Ismael; Bosco-Lauth, Angela; Fox, Christopher; Bowen, Richard A; Clements, David E; Martyak, Timothy; Parks, D Elliot; Baldwin, Susan; Reed, Steven G; Coler, Rhea N

    2016-01-01

    West Nile virus (WNV) is a mosquito-transmitted member of the Flaviviridae family that has emerged in recent years to become a serious public health threat. Given the sporadic nature of WNV epidemics both temporally and geographically, there is an urgent need for a vaccine that can rapidly provide effective immunity. Protection from WNV infection is correlated with antibodies to the viral envelope (E) protein, which encodes receptor binding and fusion functions. Despite many promising E-protein vaccine candidates, there are currently none licensed for use in humans. This study investigates the ability to improve the immunogenicity and protective capacity of a promising clinical-stage WNV recombinant E-protein vaccine (WN-80E) by combining it with a novel synthetic TLR-4 agonist adjuvant. Using the murine model of WNV disease, we find that inclusion of a TLR-4 agonist in either a stable oil-in-water emulsion (SE) or aluminum hydroxide (Alum) formulation provides both dose and dosage sparing functions, whereby protection can be induced after a single immunization containing only 100 ng of WN-80E. Additionally, we find that inclusion of adjuvant with a single immunization reduced viral titers in sera to levels undetectable by viral plaque assay. The enhanced protection provided by adjuvanted immunization correlated with induction of a Th1 T-cell response and the resultant shaping of the IgG response. These findings suggest that inclusion of a next generation adjuvant may greatly enhance the protective capacity of WNV recombinant subunit vaccines, and establish a baseline for future development.

  13. Donor-derived West Nile virus infection in solid organ transplant recipients: report of four additional cases and review of clinical, diagnostic, and therapeutic features.

    Science.gov (United States)

    Winston, Drew J; Vikram, Holenarasipur R; Rabe, Ingrid B; Dhillon, Gundeep; Mulligan, David; Hong, Johnny C; Busuttil, Ronald W; Nowicki, Marek J; Mone, Thomas; Civen, Rachel; Tecle, Selam A; Trivedi, Kavita K; Hocevar, Susan N

    2014-05-15

    We describe four solid-organ transplant recipients with donor-derived West Nile virus (WNV) infection (encephalitis 3, asymptomatic 1) from a common donor residing in a region of increased WNV activity. All four transplant recipients had molecular evidence of WNV infection in their serum and/or cerebrospinal fluid (CSF) by reverse transcription polymerase chain reaction (RT-PCR) testing. Serum from the organ donor was positive for WNV IgM but negative for WNV RNA, whereas his lymph node and spleen tissues tested positive for WNV by RT-PCR. Combination therapy included intravenous immunoglobulin (4 cases), interferon (3 cases), fresh frozen plasma with WNV IgG (2 cases), and ribavirin (1 case). Two of the four transplant recipients survived.Review of the 20 published cases of organ-derived WNV infection found that this infection is associated with a high incidence of neuroinvasive disease (70%) and severe morbidity and mortality (30%). Median time to onset of symptomatic WNV infection was 13 days after transplantation (range 5-37 days). Initial unexplained fever unresponsive to antibiotic therapy followed by rapid onset of neurologic deficits was the most common clinical presentation. Confirmation of infection was made by testing serum and CSF for both WNV RNA by RT-PCR and WNV IgM by serological assays. Treatment usually included supportive care, reduction of immunosuppression, and frequent intravenous immunoglobulin. The often negative results for WNV by current RT-PCR and serological assays and the absence of clinical signs of acute infection in donors contribute to the sporadic occurrence of donor-derived WNV infection. Potential organ donors should be assessed for unexplained fever and neurological symptoms, particularly if they reside in areas of increased WNV activity.

  14. Use of wild bird surveillance, human case data and GIS spatial analysis for predicting spatial distributions of West Nile virus in Greece.

    Directory of Open Access Journals (Sweden)

    George Valiakos

    Full Text Available West Nile Virus (WNV is the causative agent of a vector-borne, zoonotic disease with a worldwide distribution. Recent expansion and introduction of WNV into new areas, including southern Europe, has been associated with severe disease in humans and equids, and has increased concerns regarding the need to prevent and control future WNV outbreaks. Since 2010, 524 confirmed human cases of the disease have been reported in Greece with greater than 10% mortality. Infected mosquitoes, wild birds, equids, and chickens have been detected and associated with human disease. The aim of our study was to establish a monitoring system with wild birds and reported human cases data using Geographical Information System (GIS. Potential distribution of WNV was modelled by combining wild bird serological surveillance data with environmental factors (e.g. elevation, slope, land use, vegetation density, temperature, precipitation indices, and population density. Local factors including areas of low altitude and proximity to water were important predictors of appearance of both human and wild bird cases (Odds Ratio = 1,001 95%CI = 0,723-1,386. Using GIS analysis, the identified risk factors were applied across Greece identifying the northern part of Greece (Macedonia, Thrace western Greece and a number of Greek islands as being at highest risk of future outbreaks. The results of the analysis were evaluated and confirmed using the 161 reported human cases of the 2012 outbreak predicting correctly (Odds = 130/31 = 4,194 95%CI = 2,841-6,189 and more areas were identified for potential dispersion in the following years. Our approach verified that WNV risk can be modelled in a fast cost-effective way indicating high risk areas where prevention measures should be implemented in order to reduce the disease incidence.

  15. The geosimulation of West Nile virus propagation: a multi-agent and climate sensitive tool for risk management in public health

    Directory of Open Access Journals (Sweden)

    Moulin Bernard

    2008-07-01

    Full Text Available Abstract Background Since 1999, the expansion of the West Nile virus (WNV epizooty has led public health authorities to build and operate surveillance systems in North America. These systems are very useful to collect data, but cannot be used to forecast the probable spread of the virus in coming years. Such forecasts, if proven reliable, would permit preventive measures to be put into place at the appropriate level of expected risk and at the appropriate time. It is within this context that the Multi-Agent GeoSimulation approach has been selected to develop a system that simulates the interactions of populations of mosquitoes and birds over space and time in relation to the spread and transmission of WNV. This simulation takes place in a virtual mapping environment representing a large administrative territory (e.g. province, state and carried out under various climate scenarios in order to simulate the effects of vector control measures such as larviciding at scales of 1/20 000 or smaller. Results After setting some hypotheses, a conceptual model and system architecture were developed to describe the population dynamics and interactions of mosquitoes (genus Culex and American crows, which were chosen as the main actors in the simulation. Based on a mathematical compartment model used to simulate the population dynamics, an operational prototype was developed for the Southern part of Quebec (Canada. The system allows users to modify the parameters of the model, to select various climate and larviciding scenarios, to visualize on a digital map the progression (on a weekly or daily basis of the infection in and around the crows' roosts and to generate graphs showing the evolution of the populations. The basic units for visualisation are municipalities. Conclusion In all likelihood this system might be used to support short term decision-making related to WNV vector control measures, including the use of larvicides, according to climatic scenarios

  16. Prevalence of neutralizing antibodies against West Nile virus (WNV) in monkeys (Ateles geoffroyi and Alouatta pigra) and crocodiles (Crocodylus acutus and C. acutus-C. moreletti hybrids) in Mexico.

    Science.gov (United States)

    Loza-Rubio, E; Rojas-Anaya, E; López-Ramírez, R Del C; Saiz, J C; Escribano-Romero, E

    2016-08-01

    West Nile virus (WNV) is a mosquito-borne neurotropic viral pathogen maintained in an enzootic cycle between mosquitoes (vectors) and birds (natural hosts) with equids, humans, and other vertebrates acting as dead-end hosts. WNV activity in Mexico has been reported in several domestic and wild fauna and in humans, and the virus has been isolated from birds, mosquitoes, and humans. However, no serological studies have been conducted in monkeys, and only two in a limited number of crocodiles (Crocodylus moreletii). Here we present data on the prevalence of neutralizing antibodies against WNV in 53 healthy wild monkeys (49 Ateles geoffroyi and four Alouatta pigra), and 80 semi-captive healthy crocodiles (60 C. acutus and 20 C. acutus-C. moreletti hybrids) sampled during 2012. None of the monkey sera neutralized WNV, whereas 55% of the crocodile sera presented neutralizing antibodies against WNV. These results can contribute to the design of surveillance programmes in Mexico. PMID:27097655

  17. Investigating the spatial risk distribution of West Nile virus disease in birds and humans in southern Ontario from 2002 to 2005

    Directory of Open Access Journals (Sweden)

    Wilson Jeffrey

    2007-05-01

    Full Text Available Abstract Background The West Nile virus (WNv became a veterinary public health concern in southern Ontario in 2001 and has continued to threaten public health. Wild bird mortality has been shown to be an indicator for tracking the geographic distribution of the WNv. The purpose of this study was to investigate the latent risk distribution of WNv disease among dead birds and humans in southern Ontario and to compare the spatial risk patterns for the period 2002–2005. The relationship between the mortality fraction in birds and incidence rate in humans was also investigated. Methods Choropleth maps were created to investigate the spatial variation in bird and human WNv risk for the public health units of southern Ontario. The data were smoothed by empirical Bayesian estimation before being mapped. Isopleth risk maps for both the bird and human data were created to identify high risk areas and to investigate the potential relationship between the WNv mortality fraction in birds and incidence rates in humans. This was carried out by the geostatistical prediction method of kriging. A Poisson regression analysis was used to model regional human WNv case counts as a function of the spatial coordinates in the east and north direction and the regional bird mortality fractions. The presence of disease clustering and the location of disease clusters were investigated by the spatial scan test. Results The isopleth risk maps exhibited high risk areas that were relatively constant from year to year. There was an overlap in the bird and human high risk areas, which occurred in the central-west and south-west areas of southern Ontario. The annual WNv cause-specific mortality fractions in birds for 2002 to 2005 were 31.9, 22.0, 19.2 and 25.2 positive birds per 100 birds tested, respectively. The annual human WNv incidence rates for 2002 to 2005 were 2.21, 0.76, 0.13 and 2.10 human cases per 100,000 population, respectively. The relative risk of human WNv

  18. [Cases of West Nile fever in Novosibirsk region in 2004, and the genotyping of its viral pathogen].

    Science.gov (United States)

    Ternovoĭ, V A; Protopopova, E V; Kononova, Iu V; Ol'khovikova, E A; Spiridonova, E A; Akopov, G D; Shestopalov, A M; Loktev, V B

    2007-01-01

    Three cases of West Nile fever were registered for the first time in Novosibirsk region in 2004. The diagnosis was confirmed by revealing IgG against West Nile virus (three cases) and viral RNA (two cases). Sequence analysis of fragments of E protein gene showed that the virus belonged to Ia genotype. PMID:17338376

  19. West Nile viral infection of equids

    OpenAIRE

    Angenvoort, J.; Brault, A.C.; Bowen, R A; Groschup, M.H

    2013-01-01

    West Nile virus (WNV) is a flavivirus transmitted between certain species of birds and mosquito vectors. Tangential infections of equids and subsequent equine epizootics have occurred historically. Although the attack rate has been estimated to be below 10%, mortality rates can approach 50% in horses that present clinical disease. Symptoms are most commonly presenting in the form of encephalitis with ataxia as well as limb weakness, recumbency and muscle fasciculation. The most effective stra...

  20. 埃及伊蚊传播西尼罗病毒的媒介效能研究%Experimental studies on the potential of Aedes aegypti to transmit West Nile virus in China

    Institute of Scientific and Technical Information of China (English)

    张映梅; 姜淑芳; 郭晓霞; 董言德; 赵彤言

    2011-01-01

    目的 研究我国埃及伊蚊传播西尼罗病毒的潜在能力.方法 人工配制病毒血餐感染埃及伊蚊并进行传播实验,应用反转录聚合酶链反应(RT-PCR)、病毒分离和间接免疫荧光法(IFA)检测蚊虫和来亨鸡体内病毒.结果 动物实验结果表明敏感动物来亨鸡感染西尼罗病毒后,第2天其体内病毒量达到最高,说明进行传播实验后的第2天是检测传播是否成功的最佳时间.感染与传播实验结果表明埃及伊蚊对西尼罗病毒的感染率达到了63.3%,而且通过刺叮敏感动物(来亨鸡)能够传播该病毒,其传播率为30.0%.结论 在未来我国可能的西尼罗热暴发中,埃及伊蚊可能成为其在海南等地的潜在传播媒介.%Objective To evaluate the potential of Aedes aegypti to transmit West Nile virus (WNV) in China.Methods Ae.aegypti was infected orally with WNV and after 12 to 14 days' incubation allowed to transmit the virus through bite wounds.RT-PCR, virus isolation with C6/36 and indirect immunofluorescence assay were implimented to detect WNV in experimentally infected mosquitoes and Leghorn chicken.Results It was found that the WNV loaded in the susceptible host leghorn was the highest in the 2nd day after infection, indicating that it was the best time for the evaluation of the transmission.Ae.aegypti could be infected by WNV with a susceptibility rate of 63.3%, and transmitted the virus to healthy Leghorn chicken by bite wounds with a transmission rate is 30.0%.Conclusion Ae.aegypti is a potential vector of WNV in some areas such as Hainan province, likely to cause outbreaks of West Nile fever in China in future.Actions are to be taken for the control and prevention of the vecor.

  1. West Nile electrification project

    OpenAIRE

    Prototype Carbon Fund of the World Bank

    2007-01-01

    Metadata only record In early 2004, the West Nile Rural Electrification Company Ltd. plans to start up their new efficient diesel generators in the West Nile towns of Arua and Nebbi, to provide reliable power to the population during the day and most of the night. This is the first carbon finance project that has been approved in Uganda, with an Emission Reductions Purchase Agreement signed in March 2003. The company must expand their customer base quickly, because not only their income fr...

  2. West Nile virus-induced cell adhesion molecules on human brain microvascular endothelial cells regulate leukocyte adhesion and modulate permeability of the in vitro blood-brain barrier model.

    Directory of Open Access Journals (Sweden)

    Kelsey Roe

    Full Text Available Characterizing the mechanisms by which West Nile virus (WNV causes blood-brain barrier (BBB disruption, leukocyte infiltration into the brain and neuroinflammation is important to understand the pathogenesis of WNV encephalitis. Here, we examined the role of endothelial cell adhesion molecules (CAMs in mediating the adhesion and transendothelial migration of leukocytes across human brain microvascular endothelial cells (HBMVE. Infection with WNV (NY99 strain significantly induced ICAM-1, VCAM-1, and E-selectin in human endothelial cells and infected mice brain, although the levels of their ligands on leukocytes (VLA-4, LFA-1and MAC-1 did not alter. The permeability of the in vitro BBB model increased dramatically following the transmigration of monocytes and lymphocytes across the models infected with WNV, which was reversed in the presence of a cocktail of blocking antibodies against ICAM-1, VCAM-1, and E-selectin. Further, WNV infection of HBMVE significantly increased leukocyte adhesion to the HBMVE monolayer and transmigration across the infected BBB model. The blockade of these CAMs reduced the adhesion and transmigration of leukocytes across the infected BBB model. Further, comparison of infection with highly neuroinvasive NY99 and non-lethal (Eg101 strain of WNV demonstrated similar level of virus replication and fold-increase of CAMs in HBMVE cells suggesting that the non-neuropathogenic response of Eg101 is not because of its inability to infect HBMVE cells. Collectively, these results suggest that increased expression of specific CAMs is a pathological event associated with WNV infection and may contribute to leukocyte infiltration and BBB disruption in vivo. Our data further implicate that strategies to block CAMs to reduce BBB disruption may limit neuroinflammation and virus-CNS entry via 'Trojan horse' route, and improve WNV disease outcome.

  3. Construction of the recombinant adenovirus expressing E protein of West Nile virus%表达西尼罗病毒E蛋白重组腺病毒的构建及鉴定

    Institute of Scientific and Technical Information of China (English)

    张翠云; 赵晶; 陈韬; 孙恩成; 刘霓红; 杨涛; 徐青元; 王文世; 魏鹏

    2013-01-01

    To construct recombinant adenovirus expressing E protein of West Nile virus (WNV), the WNV E gene was cloned into the shuttle plasmid vector pshuttle-CMV. The resultant recombinant shuttle plasmid was linearized by Pme I and transformed into E.coli BJ5183 to construct the recombinant adenovirus plasmid of pAd-WNV-E by homologous recombination. The recombinant virus of rAd-WNV-E was generated by transfecting the Pac I linearized pAd-WNV-E into Ad-293 cells. The WNV E protein was efficiently expressed from the recombinant virus detected by western blot and immunofiuorescence assay, and the viral titration results showed that the replication ability of rAd-WNV-E was the similar to the wild type recombinant virus. These results provided the basis for further study on the recombinant virus vaccine against WNV.%为构建表达西尼罗病毒(WNV)E蛋白的重组腺病毒,本实验将WNV的E基因克隆至腺病毒穿梭载体pShuttle-CMV中,经Pme Ⅰ酶切线性化后电转化于含有人5型缺陷腺病毒的骨架的BJ5183感受态大肠杆菌中进行同源重组,构建重组质粒pAd-WNV-E;将其经Pac Ⅰ酶切线性化后通过脂质体介导转染于人胚肾细胞Ad-293细胞,制备重组腺病毒rAd-WNV-E;经western blot以及间接免疫荧光鉴定表明WNVE蛋白在Ad-293细胞中获得有效表达.病毒滴度测定试验结果显示,该重组腺病毒与野毒型腺病毒复制能力相近.该重组腺病毒的构建为进一步研制表达WNVE蛋白的重组腺病毒的疫苗奠定了基础.

  4. Discover the Nile River

    Science.gov (United States)

    Project WET Foundation, 2009

    2009-01-01

    Bordering on the Fantastic. As the longest river on earth, the Nile passes through 10 countries. Presented through a wide range of activities and a winning array of games, it's also unsurpassed at taking young minds into exploring the world of water, as well as natural and man made wonders.

  5. Is West Nile virus a potential cause of central nervous system infection in Brazil? Seria o vírus do Oeste do Nilo causa potencial de infecção no sistema nervoso central no Brasil?

    Directory of Open Access Journals (Sweden)

    Cristiane N Soares

    2010-10-01

    Full Text Available Meningitis and encephalitis are complications of West Nile virus (WNV infection. Although WNV is endemic in North America, the virus has recently been reported in Colombia and Argentina. Investigation of WNV in Brazil is important since this virus has never been studied previously in this country. OBJECTIVE: To investigate the presence of WNV infection in viral encephalitis/meningitis cases of unknown etiology in the city of Rio de Janeiro, Brazil. METHOD: Thirty-seven adults with viral meningitis/encephalitis had their serum and CSF tested for WNV antibodies using the ELISA method. RESULTS: Only one case was WNV-positive, but this case was also positive for dengue. The plaque reduction neutralization test distinguished infections, and was negative for WNV. CONCLUSION: WNV can be confused with dengue infection. Their symptoms and neurological picture are similar. We did not find WNV in any patients with encephalitis and meningitis in the city of Rio de Janeiro. Up to now, it has not been detected in BrazilMeningite e encefalite são complicações da infecção pelo vírus do Oeste do Nilo (VON. Embora o VON seja endêmico na América do Norte, recentemente o vírus foi descrito na Colômbia e Argentina. Sua pesquisa no Brasil é importante uma vez que o vírus nunca fora estudado antes em nosso país. OBJETIVO: Investigar a presença do VON em casos de meningite e encefalite viral de etiologia desconhecida, na cidade no Rio de Janeiro, Brasil. MéTODO: Trinta e sete adultos com quadro de meningite/encefalite tiveram seu LCR e soro testados para anticorpos anti-VON, pelo método ELISA. RESULTADOS: Apenas um caso obteve sorologia positiva para VON, mas a sorologia para dengue também fora positiva. O teste da neutralização por redução de placa foi utilizado para distinção entre as infecções, sendo negativo para VON. CONCLUSÃO: A infecção por VON pode ser confundida com a infecção pelo vírus da dengue, seus sintomas e quadro neurol

  6. Experimental infection of Hawai'i 'Amakihi (hemignathus virens) with West Nile virus and competence of a co-occurring vector, culex quinquefasciatus: potential impacts on endemic Hawaiian avifauna.

    Science.gov (United States)

    Lapointe, D.A.; Hofmeister, E.K.; Atkinson, C.T.; Porter, R.E.; Dusek, R.J.

    2009-01-01

    Introduced mosquito-borne avian disease is a major limiting factor in the recovery and restoration of native Hawaiian forest birds. Annual epizootics of avian pox (Avipoxvirus) and avian malaria (Plasmodium relictum) likely led to the extinction of some species and continue to impact populations of susceptible Hawaiian honeycreepers (Drepanidinae). The introduction of a novel pathogen, such as West Nile virus (WNV), could result in further population declines and extinctions. During September and October 2004, we infected Hawai'i' Amakihi (Hemignathus virens) with a North American isolate of WNV by needle inoculation and mosquito bite to observe susceptibility, mortality, and illness in this endemic passerine, and to determine the vector competence of the co-occurring, introduced mosquito Culex quinquefasciatus. All experimentally infected Hawai'i ;Amakihi became viremic, with a mean titer >10(5) plaque-forming units (PFU)/ml, and they experienced clinical signs ranging from anorexia and lethargy to ataxia. The fatality rate among needle-inoculated Hawai'i' Amakihi (n=16) was 31.3%, but mortality in free-ranging birds is likely to increase due to predation, starvation, thermal stress, and concomitant infections of avian malaria and pox. Surviving Hawai'i' Amakihi seem to clear WNV from the peripheral blood by 7-10 days postinfection (DPI), and neutralizing antibodies were detected from 9 to 46 DPI. In transmission trials, Hawaiian Cx. quinquefasciatus proved to be a competent vector and Hawai'i Amakihi an adequate amplification host of WNV, suggesting that epizootic WNV could readily become an additional limiting factor of some native Hawaiian bird populations.

  7. Mutagenesis of D80-82 and G83 Residues in West Nile Virus NS2B: Effects on NS2B-NS3 Activity and Viral Replication

    Institute of Scientific and Technical Information of China (English)

    Fan Jia; Jingjing Fan; Bo Zhang; Zhiming Yuan

    2013-01-01

    Flaviviral NS2B is a required cofactor for NS3 serine protease activity and plays an important role in promoting functional NS2B-NS3 protease configuration and maintaining critical interactions with protease catalysis substrates.The residues D80DDG in West Nile virus (WNV) NS2B are important for protease activity.To investigate the effects of D80DDG in NS2B on protease activity and viral replication,the negatively charged region D80DD and the conserved residue G83 of NS2B were mutated (D80DD/E80EE,D80DD/K80KK,D80DD/A80AA,G83F,G83S,G83D,G83K,and G83A),and NS3 D75A was designated as the negative control.The effects of the mutations on NS2B-NS3 activity,viral translation,and viral RNA replication were analyzed using kinetic analysis of site-directed enzymes and a transient replicon assay.All substitutions resulted in significantly decreased enzyme activity and blocked RNA replication.The negative charge of D80DD is not important for maintaining NS2B function,but side chain changes in G83 have dramatic effects on protease activity and RNA replication.These results demonstrate that NS2B is important for viral replication and that D80DD and G83 substitutions prevent replication; they will be useful for understanding the relationship between NS2B and NS3.

  8. 2'-O methylation of the viral mRNA cap by West Nile virus evades ifit1-dependent and -independent mechanisms of host restriction in vivo.

    Directory of Open Access Journals (Sweden)

    Kristy J Szretter

    Full Text Available Prior studies have shown that 2'-O methyltransferase activity of flaviviruses, coronaviruses, and poxviruses promotes viral evasion of Ifit1, an interferon-stimulated innate immune effector protein. Viruses lacking 2'-O methyltransferase activity exhibited attenuation in primary macrophages that was rescued in cells lacking Ifit1 gene expression. Here, we examined the role of Ifit1 in restricting pathogenesis in vivo of wild type WNV (WNV-WT and a mutant in the NS5 gene (WNV-E218A lacking 2'-O methylation of the 5' viral RNA cap. While deletion of Ifit1 had marginal effects on WNV-WT pathogenesis, WNV-E218A showed increased replication in peripheral tissues of Ifit1⁻/⁻ mice after subcutaneous infection, yet this failed to correlate with enhanced infection in the brain or lethality. In comparison, WNV-E218A was virulent after intracranial infection as judged by increased infection in different regions of the central nervous system (CNS and a greater than 16,000-fold decrease in LD(50 values in Ifit1⁻/⁻ compared to wild type mice. Ex vivo infection experiments revealed cell-type specific differences in the ability of an Ifit1 deficiency to complement the replication defect of WNV-E218A. In particular, WNV-E218A infection was impaired in both wild type and Ifit1⁻/⁻ brain microvascular endothelial cells, which are believed to participate in blood-brain barrier (BBB regulation of virus entry into the CNS. A deficiency of Ifit1 also was associated with increased neuronal death in vivo, which was both cell-intrinsic and mediated by immunopathogenic CD8⁺ T cells. Our results suggest that virulent strains of WNV have largely evaded the antiviral effects of Ifit1, and viral mutants lacking 2'-O methylation are controlled in vivo by Ifit1-dependent and -independent mechanisms in different cell types.

  9. 深圳入境旅客西尼罗病毒血清流行病学调查%Seroepidemiology investigation on west Nile virus among international travelers in Shenzhen

    Institute of Scientific and Technical Information of China (English)

    史蕾; 孙康健; 顾大勇; 徐云庆

    2012-01-01

    Objective: To investigate the infection status of west Nile virus among international travelers in Shenz-hen , discuss the optimized detection technology for this virus and make risk assessment on epidemic of this virus in-troduced by inbound travelers. Methods: Serum samples of travelers were collected from January 2009 to December 2010, and epidemiological information and detection data were analyzed. Sero - epidemiological survey has been de-ployed to the inbound travelers. ELISA test has been used to detect serum specific IgM and IgG on the target group. If the ELISA test result was positive, then a RT - PCR assay was applied for a further diagnosis. Results: A total of 447 serum samples were collected, in which 293 samples were from medical examinations on travelers, and 154 sam-ples were from quarantined travelers. The positive rates of WNV - IgG were 36.4% for medical examined travelers and 31. 8% for quarantined travelers. None of the samples was positive in WNV - IgM and RT - PCR tests. Con-clusion : The total positive rate of WNV - IgG was 38. 9% in the investigated travelers, which implied a rather high herd immunity level among the travelers, and it may cut down the risk of introducing WNV through international travelers.%目的:调查深圳入境旅客西尼罗病毒的感染情况,探讨该病毒合适的检测技术,初步对入境旅客传人该病的风险进行评估.方法:采用基于入境旅客的血清流行病学调查方法(现况调查),以ELISA检测法检测目标人群血清特异性IgM及IgG抗体,检出阳性则进一步以荧光RT-PCR检测病毒核酸以确诊,以此评估入境旅客的感染情况.结果:共收集到口岸截获发热旅客的血清154份,入境体检旅客血清293份.发热旅客WNV-IgG阳性率为31.8%,体检旅客WNV-IgG阳性率为36.5%.对抗体检测阳性血清进行荧光RT- PCR检测,未发现阳性病例.结论:所调查的入境旅客中,西尼罗病毒特异性IgG总体阳性率为38.9%,群体

  10. Natural and nosocomial infection in a patient with West Nile encephalitis and extrapyramidal movement disorders.

    Science.gov (United States)

    Solomon, Tom; Fisher, Ann F; Beasley, David W C; Mandava, Pitchaiah; Granwehr, Bruno P; Langsjoen, Hans; Travassos Da Rosa, Amelia P; Barrett, Alan D T; Tesh, Robert B

    2003-06-01

    Since its first recognition in North America in 1999, West Nile virus (WNV) has spread rapidly across the continent, but in many communities, rapid diagnostic tests for detection of WNV infection are not fully available. We describe a patient with extrapyramidal movement disorders and changes in the basal ganglia noted on magnetic resonance images that are characteristic of other flavivirus encephalitides and may help in the recognition of patients with West Nile encephalitis. Detailed molecular analysis suggested that, although our patient received a blood transfusion infected with WNV, the virus that caused his initial infection and encephalitis was probably acquired naturally from a mosquito.

  11. Sentinel site-enhanced near-real time surveillance documenting West Nile virus circulation in two Culex mosquito species indicating different transmission characteristics, Djibouti City, Djibouti.

    Science.gov (United States)

    Faulde, Michael K; Spiesberger, Michael; Abbas, Babiker

    2012-08-01

    The Horn of Africa represents a region formerly known to be highly susceptible to mosquito-borne infectious diseases. In order to investigate whether autochthonous WNV transmission occurs in the Djibouti City area, in how far, and which of, the endemic Culex mosquito species are involved in WNV circulation activity,and whether sentinel site-enhanced near-real time surveillance (SSE-NRTS) may increase WNV detection sensitivity, mosquito vector monitoring was conducted from January 2010 to June 2012. Six monitoring locations, including two identified sentinel sites, considered most probable for potential anthroponotic and zoonotic virus circulation activity, have been continuously employed. Among the 20431 mosquitoes collected, 19069 (93.4%) were Cx. quinquefasciatus, and 1345 (6.6%) Cx. pipiens ssp. torridus. WNV lineage 2 circulation activity was detected between December 20th, 2010 and January 7th, 2011. Overall, 19 WNV RNA-positive mosquito pools were detected. Generally, urban environment-specific WNV-RNA circulation took place in Cx. pipiens ssp. torridus, whereas periurban and rural area-linked circulation was detected only in Cx. quinquefasciatus. Serological investigation data from 10 volunteers employed at the dislocated zoonotic WNV transmission sentinel site suggest that six persons (60%) had an acute, or recent, WNV infection. Results show that WNV should be considered endemic for Djibouti and sentinel site-enhanced near-real time surveillance is an elegant and highly effective epidemiological tool. In Djibouti, the endemicity level, public health impact and transmission modes of vector-borne diseases in concordance with locally optimized monitoring and control regimen deserve further investigation. PMID:23214223

  12. Common Culex Mosquitoes Don't Transmit Zika Virus

    Science.gov (United States)

    ... 161186.html Common Culex Mosquitoes Don't Transmit Zika Virus: Study These widespread insects do spread West Nile ... t appear to be able to transmit the Zika virus to people, researchers report. The researchers at Kansas ...

  13. NIAID's Role in Addressing West Nile Virus

    Science.gov (United States)

    ... supported by NIAID includes Early-stage research by scientists at Oregon Health and Science University who used hydrogen peroxide treatment as a way to develop inactivated vaccines. This method is being investigated to develop vaccines for a ...

  14. West Nile Virus: Prevention and Control

    Science.gov (United States)

    ... action to protect yourself and your family. Avoid Mosquito Bites Use insect repellents when you go outdoors. Repellents containing DEET, picaridin, ... under your clothing. Take extra care during peak mosquito biting hours. Take extra care to use repellent and protective clothing from dusk to dawn or ...

  15. USGS West Nile Virus Research Strategy

    Science.gov (United States)

    Smith, Gregory; Brand, Christopher; Saito, Emi

    2003-01-01

    This plan integrates science across multiple USGS disciplines, and provides national and international opportunities for USGS collaboration with state and federal agencies, academic institutions, and non-governmental organizations throughout the Americas.

  16. Mosquito and West Nile virus monitoring program

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In 2004, in cooperation with USGS in Fort Collins, a monitoring study was established to assess the level of occurrence and potential effects of WNV on wild raptor...

  17. Quaternary history of the White Nile

    Science.gov (United States)

    williams, martin

    2014-05-01

    The White Nile only joined the Blue Nile ~0.3 Ma ago. It provides much of the low water discharge to the Nile. Without this contribution, in very dry years the Nile would dry up during the winter months. Owing to its very gentle flood gradient of 1: 100,000, the White Nile has an unusually complete alluvial record. High White Nile flood levels dated by OSL are synchronous with sapropel units S8, S7, S6, S5 and S1 in the East Mediterranean, which have astronomical ages of 217, 195, 172, 124 and 8 ka, respectively. Blue Nile palaeochannels that flow into the former White Nile complete the flood record, and coincide with sapropel units S4, S3 and S2, with respective ages of 102, 81 and 55 ka. The two most recent phases of very high White Nile flow were marked by widespread flooding across the lower White Nile valley during the last interglacial and the terminal Pleistocene - the latter coinciding with the abrupt return of the summer monsoon at 14.5 ka and the synchronous onset of humid conditions across the Sahara and East Africa, which ended suddenly at 5 ka, when desiccation set in. This humid phase was not uniformly wet; nor was the late Holocene uniformly dry. High White Nile flood levels have calibrated radiocarbon ages of 14.7-13.1, 9.7-9.0, 7.9-7.6, 6.3 and 3.2-2.8 ka obtained on freshwater gastropod shells. It was during these times that the White Nile valley was occupied successively by Mesolithic, Neolithic and Meroitic societies. West of the lower White Nile shallow ponds fed by local runoff supported an abundant gastropod fauna between 9.9 and 7.6 ka, with peak wetness at 9.0-8.4 ka, coeval with Mesolithic barbed bone harpoon sites east of the lower White Nile. The drier intervals recorded in the White Nile valley appear to coincide with times of polar cooling and more widespread tropical aridity.

  18. Late Pleistocene and Holocene environments in the Nile basin

    Science.gov (United States)

    Williams, Martin A. J.

    2009-10-01

    Owing to the very gently sloping nature of the flood plain in the lower White Nile valley, which is underlain by a former lake-bed, the depositional record in that area is unusually well preserved. In Egypt and along the Blue Nile phases of erosion have destroyed segments of the sedimentary record, but the White Nile sequence is a good proxy for both the main Nile and the Blue Nile. During the last 15 ka, at least, times of high flow in the Blue Nile and main Nile were synchronous with those in the White Nile. Not all the White Nile flood deposits have been preserved but calibrated radiocarbon dates obtained on fossil freshwater and amphibious Pila shells and fish bones indicate that White Nile levels were high around 14.7-13.1 ka, 9.7-9.0 ka, 7.9-7.6 ka, 6.3 ka and 3.2-2.8 ka. The Blue Nile record is more fragmentary and that of the main Nile even more so except for the Holocene Nile delta. Calibrated radiocarbon ages for high Blue Nile flows indicate very high flood levels towards 13.9-13.2 ka, 8.6 ka, 7.7 ka and 6.3 ka. Incision by the Blue Nile and main Nile has caused progressive incision in the White Nile amounting to at least 4 m since the terminal Pleistocene ˜ 15 ka ago and at least 2 m over the past 9 ka. The Blue Nile seems to have cut down at least 10 m since ˜ 15 ka and at least 4 m since 9 ka. The time-transgressive and relatively late inception of plant domestication in the Nile valley may partly reflect this history of incision. Nile incision would propagate upstream into the White Nile valley, draining previously swampy areas along the valley floor, which would then become accessible to cultivation.

  19. Zika Virus Outside Africa

    OpenAIRE

    Hayes, Edward B.

    2009-01-01

    Zika virus (ZIKV) is a flavivirus related to yellow fever, dengue, West Nile, and Japanese encephalitis viruses. In 2007 ZIKV caused an outbreak of relatively mild disease characterized by rash, arthralgia, and conjunctivitis on Yap Island in the southwestern Pacific Ocean. This was the first time that ZIKV was detected outside of Africa and Asia. The history, transmission dynamics, virology, and clinical manifestations of ZIKV disease are discussed, along with the possibility for diagnostic ...

  20. Peste des petits ruminants outbreaks in White Nile State, Sudan.

    Science.gov (United States)

    Ishag, Osama M; Saeed, Intisar K; Ali, Yahia H

    2015-01-01

    Eight outbreaks of peste des petits ruminants in sheep and goats were reported in White Nile State, Sudan, between 2008 and 2009. A mortality rate of 4.2% was reported across the different outbreaks. Clinically the disease was characterised by high fever, ocular and nasal discharge, pneumonia, ulceration of the mucous membranes, diarrhoea and death. The postmortem findings included necrotic lesions in the mouth and gastrointestinal tract, and swollen, oedematous lymph nodes associated with the lungs and intestine. Of the 209 serum samples tested by competitive enzyme-linked immunosorbent assay, 113 (54%) were found positive. Peste des petits ruminants virus was confirmed in tissues, nasal swabs and blood samples by immunocapture enzyme-linked immunosorbent assay, reverse-transcription polymerase chain reaction and isolation of the virus in culture of lamb testicle cells. PMID:26304168

  1. Peste des petits ruminants outbreaks in White Nile State, Sudan

    Directory of Open Access Journals (Sweden)

    Osama M. Ishag

    2015-02-01

    Full Text Available Eight outbreaks of peste des petits ruminants in sheep and goats were reported in White Nile State, Sudan, between 2008 and 2009. A mortality rate of 4.2% was reported across the different outbreaks. Clinically the disease was characterised by high fever, ocular and nasal discharge, pneumonia, ulceration of the mucous membranes, diarrhoea and death. The postmortem findings included necrotic lesions in the mouth and gastrointestinal tract, and swollen, oedematous lymph nodes associated with the lungs and intestine. Of the 209 serum samples tested by competitive enzyme-linked immunosorbent assay, 113 (54% were found positive. Peste des petits ruminants virus was confirmed in tissues, nasal swabs and blood samples by immunocapture enzyme-linked immunosorbent assay, reverse-transcription polymerase chain reaction and isolation of the virus in culture of lamb testicle cells.

  2. Shifting Sediment Sources in the Quaternary Nile

    Science.gov (United States)

    Woodward, Jamie; Macklin, Mark; Fielding, Laura; Millar, Ian; Williams, Martin

    2016-04-01

    Invited Paper The Nile basin contains the longest river channel system in the world and drains about one tenth of the African continent. A dominant characteristic of the modern Nile is the marked spatial and temporal variability in the flux of water and sediment. Because the major headwater basins of the Nile are linked to key elements of the global climate system, the sedimentary records in the basin have attracted good deal of attention from the Quaternary palaeoclimate and palaeohydrology communities. Various approaches (from heavy minerals to strontium isotopes) have been employed to examine present and past patterns of sediment yield in the basin. A good deal of work has been carried out on the long sediment records in the delta and offshore which provide high resolution archives of hydrological changes in the upstream basin as well fluctuations in the input of dust from the desert. The sediment load of the modern desert Nile (downstream of Khartoum) is dominated by sediment inputs from the Blue Nile (61 +/- 5%) and Atbara (35 +/- 4%), whilst the White Nile contribution is meagre (3 +/- 2%) (Padoan et al. 2011). Recent work has shown that these values were very different during humid phases of the Quaternary when stronger Northern Hemisphere summer insolation produced wetter conditions across North Africa. In the early Holocene, for example, the Nile floodplain in Northern Sudan shows a tributary wadi input of 40-50%. This paper will review three decades of work on the sediment delivery dynamics of the Quaternary Nile and explore their palaeoclimatic implications. Padoan, M., Garzanti, E., Harlavan, Y., Villa, I.M. (2011) Tracing Nile sediment sources by Sr and Nd isotope signatures (Uganda, Ethiopia, Sudan). Geochim. Cosmochim. Acta 75 (12), 3627-3644.

  3. Antibodies to H5 subtype avian influenza virus and Japanese encephalitis virus in northern pintails (Anas acuta) sampled in Japan

    Science.gov (United States)

    Blood samples from 105 northern pintails (Anas acuta) captured on Hokkaido, Japan were tested for antibodies to avian influenza virus (AIV), Japanese encephalitis virus (JEV) and West Nile virus (WNV) to assess possible involvement of this species in the transmission and spread of economically impor...

  4. The IFITMs Inhibit Zika Virus Replication

    Directory of Open Access Journals (Sweden)

    George Savidis

    2016-06-01

    Full Text Available Zika virus has emerged as a severe health threat with a rapidly expanding range. The IFITM family of restriction factors inhibits the replication of a broad range of viruses, including the closely related flaviruses West Nile virus and dengue virus. Here, we show that IFITM1 and IFITM3 inhibit Zika virus infection early in the viral life cycle. Moreover, IFITM3 can prevent Zika-virus-induced cell death. These results suggest that strategies to boost the actions and/or levels of the IFITMs might be useful for inhibiting a broad range of emerging viruses.

  5. The IFITMs Inhibit Zika Virus Replication.

    Science.gov (United States)

    Savidis, George; Perreira, Jill M; Portmann, Jocelyn M; Meraner, Paul; Guo, Zhiru; Green, Sharone; Brass, Abraham L

    2016-06-14

    Zika virus has emerged as a severe health threat with a rapidly expanding range. The IFITM family of restriction factors inhibits the replication of a broad range of viruses, including the closely related flaviruses West Nile virus and dengue virus. Here, we show that IFITM1 and IFITM3 inhibit Zika virus infection early in the viral life cycle. Moreover, IFITM3 can prevent Zika-virus-induced cell death. These results suggest that strategies to boost the actions and/or levels of the IFITMs might be useful for inhibiting a broad range of emerging viruses. PMID:27268505

  6. Review of Tour of the Nile [iPad App

    Directory of Open Access Journals (Sweden)

    Helen Strudwick

    2013-07-01

    Full Text Available A review of the iPad app, Tour of the Nile. The app promises 'a virtual journey along the Nile Valley' plus the chance to 'handle' objects through the technology of augmented reality.

  7. Megalocytivirus infection in cultured Nile tilapia Oreochromis niloticus.

    Science.gov (United States)

    Subramaniam, Kuttichantran; Gotesman, Michael; Smith, Charlie E; Steckler, Natalie K; Kelley, Karen L; Groff, Joseph M; Waltzek, Thomas B

    2016-05-26

    Megalocytiviruses, such as infectious spleen and kidney necrosis virus (ISKNV), induce lethal systemic diseases in both ornamental and food fish species. In this study, we investigated an epizootic affecting Nile tilapia Oreochromis niloticus cultured in the US Midwest. Diseased fish displayed lethargy, gill pallor, and distension of the coelomic cavity due to ascites. Histopathological examination revealed a severe systemic abundance of intravascular megalocytes that were especially prominent in the gills, kidney, spleen, liver, and intestinal submucosa. Transmission electron microscopic examination revealed abundant intracytoplasmic polygonal virions consistent with iridovirus infection. Comparison of the full-length major capsid protein nucleotide sequences from a recent outbreak with a remarkably similar case that occurred at the same facility many years earlier revealed that both epizootics were caused by ISKNV. A comparison of this case with previous reports suggests that ISKNV may represent a greater threat to tilapia aquaculture than previously realized. PMID:27225209

  8. OAS1 polymorphisms are associated with susceptibility to West Nile encephalitis in horses.

    Directory of Open Access Journals (Sweden)

    Jonathan J Rios

    Full Text Available West Nile virus, first identified within the United States in 1999, has since spread across the continental states and infected birds, humans and domestic animals, resulting in numerous deaths. Previous studies in mice identified the Oas1b gene, a member of the OAS/RNASEL innate immune system, as a determining factor for resistance to West Nile virus (WNV infection. A recent case-control association study described mutations of human OAS1 associated with clinical susceptibility to WNV infection. Similar studies in horses, a particularly susceptible species, have been lacking, in part, because of the difficulty in collecting populations sufficiently homogenous in their infection and disease states. The equine OAS gene cluster most closely resembles the human cluster, with single copies of OAS1, OAS3 and OAS2 in the same orientation. With naturally occurring susceptible and resistant sub-populations to lethal West Nile encephalitis, we undertook a case-control association study to investigate whether, similar to humans (OAS1 and mice (Oas1b, equine OAS1 plays a role in resistance to severe WNV infection. We identified naturally occurring single nucleotide mutations in equine (Equus caballus OAS1 and RNASEL genes and, using Fisher's Exact test, we provide evidence that mutations in equine OAS1 contribute to host susceptibility. Virtually all of the associated OAS1 polymorphisms were located within the interferon-inducible promoter, suggesting that differences in OAS1 gene expression may determine the host's ability to resist clinical manifestations associated with WNV infection.

  9. N Isotopes in Nile Sediments (ethiopia, Sudan)

    Science.gov (United States)

    Padoan, M.; Villa, I. M.; Garzanti, E.; Galbusera, M.; Quistini, S.; Peruta, L.; El Kammar, A.

    2009-04-01

    The Nile is the most important river of the Eastern Mediterranean. Its water and sediment fluxes have greatly influenced marine circulation throughout the Quaternary, and are widely considered as possible causes for stagnation and formation of sapropel (Krom et al., 1999a; 2002; Talbot et al., 2000; Freydier et al., 2001; Weldeab et al., 2002; Scrivner et al., 2004). Variations in annual flooding and baseflow of the river Nile, controlled by climate changes, had major impact on the rise and demise of Egyptian dynasties (Stanley et al., 2003). In order to better define sedimentary sources of the Nile system and to obtain more robust results, we have analyzed Nd isotopes in sediments of all its major Sudanese and Ethiopian tributaries (Atbara, Gash, Abay, Didesa, Dabus, White Nile, Bahr Ez Zeraf) in several replicate samples. Analyses were carried out on distinct mud and sand fractions (STANLEY, J.D., CLIFF, R.A., WOODWARD, J.C., 2002. Nile River sediment fluctuations over the past 7000 yr and their key role in sapropel development. Geol., 30, n. 1, 71-74. PADOAN M., GALBUSERA M., QUISTINI S., VILLA I.M., AND GARZANTI E., 2007 Isotopic tracers of Nile sediment sources. AGU Fall Meeting, San Francisco December 2007. PIK, R., DENIEL, C., COULON, C., YIRGU, G., MARTY, B., 1999, Isotopic and trace element signatures of Ethiopian flood basalts: Evidence for plume-lithosphere interactions. Geochim. Cosmochim. Acta, 63, 2263-2279. SCRIVNER, A., VANCE, D., ROHLING, E.J., 2004. New neodymium isotope data quantify Nile involvement in Mediterranean anoxic episodes. Geol., 32, n. 7, 565-568. STANLEY, J.D., KROM, M.D., CLIFF, R.A., WOODWARD, J.C., 2003. Short Contribution: Nile flow failure at the End of the Old Kingdom, Egypt: strontium isotopic and petrologic evidence. TALBOT, M.R., WILLIAMS, M.A.J., ADAMSON, D.A., 2000. Strontium isotope evidence for late Pleistocene reestablishment of an integrated Nile drainage network. Geol., 28, n. 4, 343-346. WELDEAB, S., EMEIS, K

  10. The IFITMs Inhibit Zika Virus Replication

    OpenAIRE

    George Savidis; Jill M. Perreira; Jocelyn M. Portmann; Paul Meraner; Zhiru Guo; Sharone Green; Abraham L. Brass

    2016-01-01

    Zika virus has emerged as a severe health threat with a rapidly expanding range. The IFITM family of restriction factors inhibits the replication of a broad range of viruses, including the closely related flaviruses West Nile virus and dengue virus. Here, we show that IFITM1 and IFITM3 inhibit Zika virus infection early in the viral life cycle. Moreover, IFITM3 can prevent Zika-virus-induced cell death. These results suggest that strategies to boost the actions and/or levels of the IFITMs mig...

  11. Animal viral diseases and global change: Bluetongue and West Nile fever as paradigms

    Directory of Open Access Journals (Sweden)

    Miguel Angel eJimenez-Clavero

    2012-06-01

    Full Text Available Environmental changes have an undoubted influence on the appearance, distribution and evolution of infectious diseases, and notably on those transmitted by vectors. Global change refers to environmental changes arising from human activities affecting the fundamental mechanisms operating in the biosphere. This paper discusses the changes observed in recent times with regard to some important arboviral (arthropod-borne viral diseases of animals, and the role global change could have played in these variations. Two of the most important arboviral diseases of animals, bluetongue and West Nile fever/encephalitis, have been selected as models. In both cases, in the last 15 years an important leap forward has been observed, which has lead to considering them emerging diseases in different parts of the world. Bluetongue, affecting domestic ruminants, has recently afflicted livestock in Europe in an unprecedented epizootic, causing enormous economic losses. West Nile fever/encephalitis affects wildlife (birds, domestic animals (equines and humans, thus, beyond the economic consequences of its occurrence, as a zoonotic disease, it poses an important public health threat. West Nile virus has expanded in the last 12 years worldwide, and particularly in the Americas, where it first occurred in 1999, extending throughout the Americas relentlessly since then, causing a severe epidemic of disastrous consequences for public health, wildlife and livestock. In Europe, West Nile virus is known long time ago, but it is since the last years of the XXth century that its incidence has risen substantially. Circumstances such as global warming, changes in land use and water management, increase in travel, trade of animals, and others, can have an important influence in the observed changes in both diseases. The following question is raised: What is the contribution of global changes to the current increase of these diseases in the world?

  12. 广东从化无规定马属动物疫病区野鸟和蚊子分布及其西尼罗病毒感染情况调查%Investigation on Distribution of Wild Birds and Mosquitoes and West Nile Virus Infec-tion Status in the Speciif c Equine Disease-free Zone of Conghua,Guangdong Province

    Institute of Scientific and Technical Information of China (English)

    张海冰; 段晓冬; 沈丹; 郑丽兰; 杨穗娟; 谭诺; 张海明

    2014-01-01

    Objective To investigate the species,number and distribution of wild birds and mosquitoes and West Nile virus(WNV)the specific equine disease-free zone of Conghua,Guangdong.Method The birds were captured on the migration routes with nets,and mosquitoes by Ultraviolet light trapping and nets.The samples were detected with real-time RT-PCR assay for West Nile virus.Result All the 381 birds of 110 species and 3048 mosquitoes of 5 species collected were negative for West Nile virus.Conclusion No WNV-positive birds and mosquitoes were detected in the survey.There were amount of potential vectors of WNV found in the zone.To maintain the disease-free status of the specifi c equine disease-free zone of Conghua,further work was needed to monitor the bird and mosquito activities for long time.%[目的]了解广东从化无规定马属动物疫病区野鸟和蚊子的种类、数量和分布等情况及其西尼罗病毒感染的情况。[方法]对鸟类在沿途设网抓捕取样;蚊虫采用紫外灯诱捕和网捕进行样品采集,随后利用荧光定量RT-PCR方法对西尼罗病毒进行检测。[结果]2012-2013年该地区共捕获鸟类110种381只,隶属于12目37科76属;共捕获蚊虫5种,共计3048只,其中淡色库蚊占50.66%、三带喙库蚊占32.12%、褐尾库蚊占12.99%、中华按蚊占3.61%和白纹伊蚊0.62%;对381份鸟泄殖腔棉拭子和3048份蚊子样品进行了西尼罗病毒的检测,结果均为阴性。[结论]虽然本次调查未发现鸟类及蚊子感染西尼罗病毒,但本地区存在西尼罗病毒引入以及在本地区传播的条件,存在西尼罗病毒病发生风险。因此,为继续维持广东从化无规定马属动物疫病区的无疫状态,有必要对媒介鸟类及蚊虫开展长期的调查和监测。

  13. Production of Genetically Improved Organic Nile Tilapia

    NARCIS (Netherlands)

    Charo, H.; Komen, J.; Bovenhuis, H.; Rezk, M.A.; Ponzoni, R.W.

    2008-01-01

    Demand for organic products for human consumption has been on the increase due to the belief that organic products are safer and healthier to the consumer and the environment. In developing countries, Nile tilapia (Oreochromis niloticus) is usually grown in low-input organically fed ponds with littl

  14. Tracking Nile Delta vulnerability to Holocene change.

    Directory of Open Access Journals (Sweden)

    Nick Marriner

    Full Text Available Understanding deltaic resilience in the face of Holocene climate change and human impacts is an important challenge for the earth sciences in characterizing the full range of present and future wetland responses to global warming. Here, we report an 8000-year mass balance record from the Nile Delta to reconstruct when and how this sedimentary basin has responded to past hydrological shifts. In a global Holocene context, the long-term decrease in Nile Delta accretion rates is consistent with insolation-driven changes in the 'monsoon pacemaker', attested throughout the mid-latitude tropics. Following the early to mid-Holocene growth of the Nile's deltaic plain, sediment losses and pronounced erosion are first recorded after ~4000 years ago, the corollaries of falling sediment supply and an intensification of anthropogenic impacts from the Pharaonic period onwards. Against the backcloth of the Saharan 'depeopling', reduced river flow underpinned by a weakening of monsoonal precipitation appears to have been particularly conducive to the expansion of human activities on the delta by exposing productive floodplain lands for occupation and irrigation agriculture. The reconstruction suggests that the Nile Delta has a particularly long history of vulnerability to extreme events (e.g. floods and storms and sea-level rise, although the present sediment-starved system does not have a direct Holocene analogue. This study highlights the importance of the world's deltas as sensitive archives to investigate Holocene geosystem responses to climate change, risks and hazards, and societal interaction.

  15. Visualising DNA in Classrooms Using Nile Blue

    Science.gov (United States)

    Milne, Christine; Roche, Scott; McKay, David

    2008-01-01

    Giving students the opportunity to extract, manipulate and visualise DNA molecules enhances a constructivist approach to learning about modern techniques in biology and biotechnology Visualisation usually requires agarose gel electrophoresis and staining. In this article, we report on an alternative DNA stain, Nile Blue A, that may be used in the…

  16. Outcomes of West Nile encephalitis patients after 1 year of West Nile encephalitis outbreak in Kerala, India: A follow-up study.

    Science.gov (United States)

    Balakrishnan, Anukumar; Thekkekara, Romy Jose; Tandale, Babasheb V

    2016-11-01

    We reported an acute encephalitis syndrome outbreak in Alappuzha district in Kerala, India during the year 2011. The etiology was confirmed to be West Nile virus lineage 1. Many encephalitis patients from this outbreak exhibited neurological sequelae post recovery. This study was aimed to assess the clinical outcomes of West Nile encephalitis confirmed case-patients after 1 year of acute illness. Forty West Nile virus confirmed encephalitis patients were selected from the 2011 outbreak was included in this study. Out of 40 cases, only 30 survived after 12 months. Among these 30 recovered case-patients, 27 (90%) consented for clinical follow-up and 23 (73.67%) of them consented for assessment of cognitive impairment and deposition of blood sample for antibody testing. The most common symptom observed in these patients was fatigue (25.93%). Other symptoms included dizziness (7.4%), decreased sense of hearing (7.4%) and decreased sense of smell (7.4%). Reduced power in limbs was found in 33.33% of the cases. Most of the patients (23.1%) were dependent on others for normal daily living activities. The patients also had probable risk of poor cognition (29.41%) and dementia (57.14%). None of the patients were positive for WNV specific IgM at 12 months post onset of disease. The study concluded that the long-term sequelae were noticed in WNV positive patients. Prevention effort should be focused on the elderly (≥60 years old) people who have a higher risk of severe sequelae. The state health authorities should create awareness among people in order to prevent the transmission of disease. J. Med. Virol. 88:1856-1861, 2016. © 2016 Wiley Periodicals, Inc.

  17. 20,000 years of Nile River dynamics and environmental changes in the Nile catchment area as inferred from Nile upper continental slope sediments

    Science.gov (United States)

    Revel, Marie; Ducassou, E.; Skonieczny, C.; Colin, C.; Bastian, L.; Bosch, D.; Migeon, S.; Mascle, J.

    2015-12-01

    Multi-proxy analysis of two marine sediment cores (MS27PT and MD04-2726) from the Nile continental slope provides evidence of changes in Nile sediment discharge related to changes in Ethiopian African Monsoon (EAM) precipitation, and allows us to reconstruct changes in Nile River runoff, vegetation and erosion in the Nile headwaters. Sediment element composition and neodymium isotopic composition reveal significant changes in clastic sediment provenance, with sources oscillating between a Saharan aeolian contribution during the Last Glacial Maximum/deglacial transition and during the Late Holocene, and a Blue/Atbara Nile fluvial contribution during the African Humid Period (AHP). This study provides a new understanding of past environmental changes. Between 14.6 and 14.13 ka there was a major input of sediments from the Ethiopian Highlands, consistent with a stronger EAM at that time. Climate in the Nile basin was wetter between 14.8 and 8.4 ka, with a corresponding increase in Blue Nile water and sediment discharge via the main Nile into the Eastern Mediterranean. The gradual climatic transition from the AHP to the present-day dry climate was reflected in a decrease in Blue Nile sediment deposition and flood discharge between 8.4 and 3.7 ka, with aridity at a maximum between 3.7 and 2.6 ka. The onset of drier conditions in the Blue Nile basin seems to have begun before the 8.2 ka cooling event in the North Atlantic. We speculate that the climatic change from the wet AHP to the dry late Holocene may have been a result of a break in the low latitude dynamic equilibrium between climate, vegetation and erosion, which may in turn have affected the climate in higher latitudes. Reduced Nile flow may also have had an impact on Levantine Intermediate Water originating in the Eastern Mediterranean through an increase in intermediate water formation.

  18. Emerging mosquito-borne viruses: transmission and modulation of host defence

    NARCIS (Netherlands)

    Fros, J.J.

    2015-01-01

    Summary Two highly pathogenic arthropod-borne (arbo)viruses, West Nile virus (WNV) and chikungunya virus (CHIKV), recently (re-)emerged in both Europe and the Americas. This resulted in large-scale epidemics of severe encephalitic and arthritogenic human disease, respectively. Both

  19. Identification and characterization of microRNAs and their target genes from Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Huang, Yong; Ma, Xiu Ying; Yang, You Bing; Ren, Hong Tao; Sun, Xi Hong; Wang, Li Rui

    2016-01-01

    MicroRNAs (miRNAs) are a class of small single-stranded, endogenous 21-22 nt non-coding RNAs that regulate their target mRNA levels by causing either inactivation or degradation of the mRNAs. In recent years, miRNA genes have been identified from mammals, insects, worms, plants, and viruses. In this research, bioinformatics approaches were used to predict potential miRNAs and their targets in Nile tilapia from the expressed sequence tag (EST) and genomic survey sequence (GSS) database, respectively, based on the conservation of miRNAs in many animal species. A total of 19 potential miRNAs were detected following a range of strict filtering criteria. To test the validity of the bioinformatics method, seven predicted Nile tilapia miRNA genes were selected for further biological validation, and their mature miRNA transcripts were successfully detected by stem-loop RT-PCR experiments. Using these potential miRNAs, we found 56 potential targets in this species. Most of the target mRNAs appear to be involved in development, metabolism, signal transduction, transcription regulation and stress responses. Overall, our findings will provide an important foundation for further research on miRNAs function in the Nile tilapia. PMID:27305701

  20. Drought in the Nile Basin: characterizing variability, quantifying uncertainty, and studying processes with the Nile Land Data Assimilation System

    Science.gov (United States)

    Alo, C. A.; Zaitchik, B. F.; Habib, S.; Anderson, M. C.; Ozdogan, M.

    2010-12-01

    The Nile Land Data Assimilation System (Nile LDAS) has been developed to support studies of hydrologic variability, land cover patterns, and climate change impacts in the countries that share the Nile basin. Here we present results of retrospective Nile LDAS simulations that examine climatic and hydrologic variability across the basin in recent decades. Use of Nile LDAS in this study allows us to compare patterns of drought as captured by different precipitation datasets—including Tropical Rainfall Measurement Mission (TRMM) precipitation products, the CPC Merged Analysis of Precipitation (CMAP), and multiple meteorological reanalyses—different land surface models—including Noah Land Surface Model, the Common Land Model, and Catchment LSM—and independent satellite observations—including the Gravity Recovery and Climate Experiment (GRACE). Results of Nile LDAS simulations show distinct temporal and spatial patterns of drought across the climatic gradients of the Nile basin. These results also demonstrate that diagnosis of drought patterns is sensitive to choice of meteorological dataset and land surface model. We present an objective classification of drought susceptibility zones based on the results of these Nile LDAS simulations, including assessment of confidence and uncertainty. Lastly, we discuss the possible drivers of hydrological variability at the local to the basin scale. Follow-on studies are in progress to merge, compare, and improve Nile LDAS datasets in order to provide optimal estimates of hydrological states and fluxes in the Nile basin, with the ultimate objective of improving drought analysis and response in an evolving climate.

  1. Zika Virus: the Latest Newcomer

    OpenAIRE

    Saiz, Juan-Carlos; Vázquez-Calvo, Ángela; Blázquez, Ana B.; Merino-Ramos, Teresa; Escribano-Romero, Estela; Martín-Acebes, Miguel A.

    2016-01-01

    Since the beginning of this century, humanity has been facing a new emerging, or re-emerging, virus threat almost every year: West Nile, Influenza A, avian flu, dengue, Chikungunya, SARS, MERS, Ebola, and now Zika, the latest newcomer. Zika virus (ZIKV), a flavivirus transmitted by Aedes mosquitoes, was identified in 1947 in a sentinel monkey in Uganda, and later on in humans in Nigeria. The virus was mainly confined to the African continent until it was detected in south-east Asia the 1980’s...

  2. Zika virus: the latest newcomer

    OpenAIRE

    Juan-Carlos eSaiz; Angela eVazquez-Calvo; Ana Belen Blazquez; Teresa eMerino-Ramos; Estela eEscribano-Romero; Martín-Acebes, Miguel A.

    2016-01-01

    Since the beginning of this century, humanity has been facing a new emerging, or re-emerging, virus threat almost every year: West Nile, Influenza A, avian flu, dengue, Chikungunya, SARS, MERS, Ebola, and now Zika, the latest newcomer. Zika virus (ZIKV), a flavivirus transmitted by Aedes mosquitoes, was identified in 1947 in a sentinel monkey in Uganda, and later on in humans in Nigeria. The virus was mainly confined to the African continent until it was detected in south-east Asia the 1980´s...

  3. Deeper understanding of Flaviviruses including Zika virus by using Apriori Algorithm and Decision Tree

    OpenAIRE

    Yang Youjin; Gu Bokyung; Yoon Taeseon

    2016-01-01

    Zika virus is spreaded by mosquito. There is high probability of Microcephaly. In 1947, the virus was first found from Uganda, but it has broken outall around world, specially North and south America. So, apriori algorithm and decision tree were used to compare polyprotein sequences of zika virus among other flavivirus; Yellow fever, West Nile virus, Dengue virus, Tick borne encephalitis. By this, dissimilarity and similarity about them were found.

  4. Deeper understanding of Flaviviruses including Zika virus by using Apriori Algorithm and Decision Tree

    Directory of Open Access Journals (Sweden)

    Yang Youjin

    2016-01-01

    Full Text Available Zika virus is spreaded by mosquito. There is high probability of Microcephaly. In 1947, the virus was first found from Uganda, but it has broken outall around world, specially North and south America. So, apriori algorithm and decision tree were used to compare polyprotein sequences of zika virus among other flavivirus; Yellow fever, West Nile virus, Dengue virus, Tick borne encephalitis. By this, dissimilarity and similarity about them were found.

  5. Hydroclimatology of the Nile: results from a regional climate model

    Directory of Open Access Journals (Sweden)

    Y. A. Mohamed

    2005-01-01

    Full Text Available This paper presents the result of the regional coupled climatic and hydrologic model of the Nile Basin. For the first time the interaction between the climatic processes and the hydrological processes on the land surface have been fully coupled. The hydrological model is driven by the rainfall and the energy available for evaporation generated in the climate model, and the runoff generated in the catchment is again routed over the wetlands of the Nile to supply moisture for atmospheric feedback. The results obtained are quite satisfactory given the extremely low runoff coefficients in the catchment. The paper presents the validation results over the sub-basins: Blue Nile, White Nile, Atbara river, the Sudd swamps, and the Main Nile for the period 1995 to 2000. Observational datasets were used to evaluate the model results including radiation, precipitation, runoff and evaporation data. The evaporation data were derived from satellite images over a major part of the Upper Nile. Limitations in both the observational data and the model are discussed. It is concluded that the model provides a sound representation of the regional water cycle over the Nile. The sources of atmospheric moisture to the basin, and location of convergence/divergence fields could be accurately illustrated. The model is used to describe the regional water cycle in the Nile basin in terms of atmospheric fluxes, land surface fluxes and land surface-climate feedbacks. The monthly moisture recycling ratio (i.e. locally generated/total precipitation over the Nile varies between 8 and 14%, with an annual mean of 11%, which implies that 89% of the Nile water resources originates from outside the basin physical boundaries. The monthly precipitation efficiency varies between 12 and 53%, and the annual mean is 28%. The mean annual result of the Nile regional water cycle is compared to that of the Amazon and the Mississippi basins.

  6. The Carbon Cycle at the Nile Headwaters

    Science.gov (United States)

    Jones, Michael; Saunders, Matthew

    2014-05-01

    The carbon cycle at the Nile headwaters M B Jones, School of Natural Sciences, Trinity College, University of Dublin, Dublin 2, Ireland M Saunders, Environmental and Biochemical Sciences Group, The James Hutton Institute, Aberdeen, Scotland River systems play an integral role in the global carbon cycle by connecting the terrestrial biosphere, the atmosphere and the oceans. Extensive wetland systems, such as those found in the Amazon region, have been shown to export significant amounts of carbon to river waters as dissolved carbon dioxide (CO2) that can be transported and emitted hundreds of km downstream. The assessment of both regional and global carbon budgets could therefore be improved by quantifying these lateral carbon fluxes, especially from highly productive temporarily or permanently flooded areas where substantial CO2 evasion from inland waters can occur. The Nile is the longest river in the world and the headwaters are located in the extensive Papyrus dominated wetlands in central Africa that are associated with Lake Victoria. From its source the White Nile flows northwards through wetlands in Uganda and Sudan before it joins the Blue Nile. Papyrus wetlands have been shown to be some of the most productive global ecosystems, with recorded rates of aerial net primary productivity of up to 3.09 kg C m-2 yr-1. In addition, where anaerobic conditions occur they also accumulate large amounts of carbon in the form of peat, and under these circumstances they represent a significant carbon sink. However, as water moves through these wetlands and is exchanged with surrounding rivers and lakes significant quantities of dissolved organic and inorganic carbon as well as suspended particulate organic matter are exported, which are either released further downstream by degassing, decomposition or deposition. Information on such losses from these wetland ecosystems is extremely sparse but in order to better constrain ecosystem scale carbon dynamics more accurate

  7. Epidemiology of West Nile Disease in Europe and in the Mediterranean Basin from 2009 to 2013

    Directory of Open Access Journals (Sweden)

    Daria Di Sabatino

    2014-01-01

    Full Text Available West Nile virus (WNV transmission has been confirmed in the last four years in Europe and in the Mediterranean Basin. An increasing concern towards West Nile disease (WND has been observed due to the high number of human and animal cases reported in these areas confirming the importance of this zoonosis. A new epidemiological scenario is currently emerging: although new introductions of the virus from abroad are always possible, confirming the epidemiological role played by migratory birds, the infection endemisation in some European territories today is a reality supported by the constant reoccurrence of the same strains across years in the same geographical areas. Despite the WND reoccurrence in the Old World, the overwintering mechanisms are not well known, and the role of local resident birds or mosquitoes in this context is poorly understood. A recent new epidemiological scenario is the spread of lineage 2 strain across European and Mediterranean countries in regions where lineage 1 strain is still circulating creating favourable conditions for genetic reassortments and emergence of new strains. This paper summarizes the main epidemiological findings on WNV occurrence in Europe and in the Mediterranean Basin from 2009 to 2013, considering potential future spread patterns.

  8. Nile behaviour and Upper Palaeolithic humans in Upper Egypt

    Science.gov (United States)

    Vermeersch, Pierre M.

    2014-05-01

    There is evidence of a decreasing human occupation of the Upper Egyptian Nile valley during the MIS 5 to MIS 3 period. Whereas very large extraction sites of the Middle Stone Age have been recorded, only very few sites of the Upper Palaeolithic have been found. The best explanation of this fact is that during the Late Middle Stone Age and the Upper Palaeolithc there was nearly no need for raw materials because there was only a very restricted population present in Upper Egypt. From about 22 ka BP an important population increase is registered by the presence of numerous Late Palaeolithic sites. During the whole LGM there is abundant presence of humans along the Nile Valley in Upper Egypt. This population was mainly living from fishing. There seems to be an abrupt end of the Palaeolithic occupation after 12.8 ka BP. Until now, no sites were found in the Valley until some rare Epipaleolithic sites occur about 8.0 ka BP. It will be suggested that these population changes are influenced by the river Nile behaviour. The best interpretation of the observations in the Upper Egyptian Nile Valley is the hypothesis that at the same time that Nile flow was reduced because of the dryness in its source area, the impact of aeolian activity was increased over Northeast Africa. The increased aeolian activity by northern winds in the Fayum and Wadi Ryan during the LGM resulted in the accumulation of aeolian sand in the valley. That aeolian sand was transported along the western Nile valley cliffs until it was accumulated when the Nile Valley change it S-N direction, such as at Nag'Hammadi. At other places sand was invading the Nile valley, directly from the Western Desert, creating a damming of the Nile at several places such as Armant and Aswan. As Nile flow was quite reduced, the Nile was unable to erode all the incoming sand and the Nile water with its important clay content was dammed. At several places large lakes were created in the Nile Valley. Those lakes were an ideal

  9. A GEOSPATIAL STUDY OF THE POTENTIAL OF TWO EXOTIC SPECIES OF MOSQUITOES TO IMPACT THE EPIDEMIOLOGY OF WEST NITLE VIRUS IN MARYLAND

    Science.gov (United States)

    Geospatial techniques were used to study the potential impact of two exotic mosquitoes, the Asian tiger mosquito, Aedes albopictus (Skuse) and Ochlerotatus japonicus japonicus (Theobald), on the epidemiology of West Nile virus in Maryland. These two species have established p...

  10. Hydroclimatology of the Nile: results from a regional climate model

    Directory of Open Access Journals (Sweden)

    Y. A. Mohamed

    2005-02-01

    Full Text Available This paper is the result of the first regional coupled climatic and hydrologic model of the Nile. For the first time the interaction between the climatic processes and the hydrological processes on the land surface have been fully coupled. The hydrological model is driven by the rainfall and the energy available for evaporation generated in the climate model, and the runoff generated in the catchment is again routed over the wetlands of the Nile to supply moisture for atmospheric feedback. The results obtained are surprisingly accurate given the extremely low runoff coefficients in the catchment.

    The paper presents model results over the sub-basins: Blue Nile, White Nile, Atbara river and the Main Nile for the period 1995 to 2000, but focuses on the Sudd swamp. Limitations in both the observational data and the model are discussed. It is concluded that the model provides a sound representation of the regional water cycle over the Nile. The model is used to describe the regional water cycle in the Nile basin in terms of atmospheric fluxes, land surface fluxes and land surface-climate feedbacks. The monthly moisture recycling ratio (i.e. locally generated/total precipitation over the Nile varies between 8 and 14%, with an annual mean of 11%, which implies that 89% of the Nile water resources originates from outside the basin physical boundaries. The monthly precipitation efficiency varies between 12 and 53%, and the annual mean is 28%. The mean annual result of the Nile regional water cycle is compared to that of the Amazon and the Mississippi basins.

  11. 21 CFR 866.3940 - West Nile virus serological reagents.

    Science.gov (United States)

    2010-04-01

    ..., from individuals who have signs and symptoms consistent with viral meningitis/encephalitis. The detection aids in the clinical laboratory diagnosis of viral meningitis/encephalitis caused by West...

  12. Alexander the Great and West Nile Virus Encephalitis

    OpenAIRE

    Marr, John S.; Calisher, Charles H.

    2003-01-01

    Alexander the Great died in Babylon in 323 BC. His death at age 32 followed a 2-week febrile illness. Speculated causes of death have included poisoning, assassination, and a number of infectious diseases. One incident, mentioned by Plutarch but not considered by previous investigators, may shed light on the cause of Alexander’s death. The incident, which occurred as he entered Babylon, involved a flock of ravens exhibiting unusual behavior and subsequently dying at his feet. The inexplicable...

  13. Nile Blue derivatives as lysosomotropic photosensitizers

    Science.gov (United States)

    Lin, Chi-Wei; Shulok, Janine R.; Kirley, S. D.; Cincotta, Louis; Foley, James W.

    1991-06-01

    The benzophenoxazines, including several Nile blue analogues, are a unique group of dyes that localize selectively in animal tumors. Chemical modifications of Nile blue A can yield derivatives with high 1O2 quantum yields. These derivatives represent a group of potentially effective photosensitizers for selective phototherapy of malignant tumors. In vitro evaluation of these derivatives has indicated that those with high 1O2 yields are very effective in mediating the photocytotoxicity of tumor cells. This photodynamic effect is most likely mediated through the action of 1O2, since photoirradiation under D2O enhanced and under hypoxic conditions diminished the photocytotoxic action. The subcellular localization of these photosensitizers in bladder tumor cells in culture was examined by light and fluorescence microscopies as well as by histochemical and biochemical studies. The results indicate that these dyes are localized primarily in the lysosome. The cellular uptake and retention of these dyes is energy- and pH-dependent. Agents such as nigericin, which alter the transmembrane pH gradient, reduced uptake and enhanced efflux of the dyes, while agents such as valinomycin, which reduce cellular membrane potential, had no effect on the uptake. These findings are consistent with having ion-trapping as the mechanism for the uptake of these dyes. Photoirradiation of sensitizer-treated cells obliterated lysosomes in a light-dose and drug-dose dependent fashion. Release of the hydrolytic enzymes may be the main cause for subsequent cell death since the cytolytic effect was reduced by a specific inhibitor of lysosomal proteolytic enzyme. A lysosomotropic photosensitization mechanism is therefore proposed for the photocytotoxic action of the Nile blue derivatives. This mechanism may provide an approach to the development of new photosensitizers for the effective and selective destruction of malignant tumors.

  14. Taxonomy Icon Data: Nile crocodile [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Nile crocodile Crocodylus niloticus Chordata/Vertebrata/Reptilia/etc Crocodylus_nil...oticus_L.png Crocodylus_niloticus_NL.png Crocodylus_niloticus_S.png Crocodylus_niloticus_NS.png http://biosc...iencedbc.jp/taxonomy_icon/icon.cgi?i=Crocodylus+niloticus&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Crocodylus+ni...loticus&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Crocodylus+ni...loticus&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Crocodylus+niloticus&t=NS ...

  15. Rising Sea Levels threatens the Nile Delta

    OpenAIRE

    Attia, Shady

    2007-01-01

    Like many other deltas, Egypt is particularly vulnerable to the effects of global warming. A relative rise in sea-level of 1 m would submerge much of the delta region within 30 km of the coast during the next 100 years. Rising sea levels would have significant long-term impacts on physical, biological and socio-economic conditions of the Nile Delta. These include the damage and destruction of buildings near beaches, erosion of beaches, salt-water intrusion, and flooding more than 1,200 km2 o...

  16. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt

    Directory of Open Access Journals (Sweden)

    Ayman Mohamed Megahed

    2015-01-01

    Full Text Available Ten polychlorinated biphenyl (PCB congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD. PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt.

  17. Nile Delta vegetation response to Holocene climate variability

    Science.gov (United States)

    Bernhardt, Christopher E.; Horton, Benjamin P.; Stanley, Jean-Daniel

    2012-01-01

    A 7000 yr palynologic record from Burullus Lagoon, Nile Delta, Egypt, is assessed to investigate changes in terrestrial vegetation in response to Nile flow. Previous studies in this region have shown that sea-level rise in the early to mid-Holocene, and markedly increased human land use during the past several centuries, altered vegetation in and around the lagoon. The pollen record from this study documents changes in delta vegetation that likely reflect variations in Nile flow. We suggest that Cyperaceae pollen is a sensitive marker of precipitation over the Nile headwaters and the resultant Nile flow. Decreases in Cyperaceae pollen, interpreted as a marker for diminished Nile flow, as well as the increase in relative abundance of microscopic charcoal, occurred at ca. 6000–5500, ca. 5000, ca. 4200, and ca. 3000 cal. yr B.P. (calibrated years before present). These correspond to extreme regional and global aridity events associated with a more southerly mean position of the Intertropical Convergence Zone. These changes, also recorded by other proxy studies, indicate that several marked regional drought events affected the Nile Delta region and impacted ancient Egyptian and Middle Eastern civilizations.

  18. Multiplex qRT-PCR for the Detection of Western Equine Encephalomyelitis, St. Louis Encephalitis, and West Nile Viral RNA in Mosquito Pools (Diptera: Culicidae).

    Science.gov (United States)

    Brault, Aaron C; Fang, Ying; Reisen, William K

    2015-05-01

    Following the introduction of West Nile virus into California during the summer of 2003, public health and vector control programs expanded surveillance efforts and were in need of diagnostics capable of rapid, sensitive, and specific detection of arbovirus infections of mosquitoes to inform decision support for intervention. Development of a multiplex TaqMan or real-time semiquantitative reverse transcription polymerase chain reaction (RT-PCR) assay in which three virus specific primer-probe sets were used in the same reaction is described herein for the detection of western equine encephalomyelitis, St. Louis encephalitis and West Nile viral RNA. Laboratory validation and field data from 10 transmission seasons are reported. The comparative sensitivity and specificity of this multiplex assay to singleplex RT-PCR as well as an antigen detection (rapid analyte measurement platform) and standard plaque assays indicate this assay to be rapid and useful in providing mosquito infection data to estimate outbreak risk. PMID:26334826

  19. Purification and crystallization of Kokobera virus helicase

    International Nuclear Information System (INIS)

    Kokobera virus is a mosquito-borne flavivirus belonging, like West Nile virus, to the Japanese encephalitis virus serocomplex. Crystals of the Kokobera virus helicase domain were obtained by the hanging-drop vapour-diffusion method and exhibit a diffraction limit of 2.3 Å. Kokobera virus is a mosquito-borne flavivirus belonging, like West Nile virus, to the Japanese encephalitis virus serocomplex. The flavivirus genus is characterized by a positive-sense single-stranded RNA genome. The unique open reading frame of the viral RNA is transcribed and translated as a single polyprotein which is post-translationally cleaved to yield three structural and seven nonstructural proteins, one of which is the NS3 gene that encodes a C-terminal helicase domain consisting of 431 amino acids. Helicase inhibitors are potential antiviral drugs as the helicase is essential to viral replication. Crystals of the Kokobera virus helicase domain were obtained by the hanging-drop vapour-diffusion method. The crystals belong to space group P3121 (or P3221), with unit-cell parameters a = 88.6, c = 138.6 Å, and exhibit a diffraction limit of 2.3 Å

  20. Purification and crystallization of Kokobera virus helicase

    Energy Technology Data Exchange (ETDEWEB)

    De Colibus, Luigi; Speroni, Silvia [Department of Genetics and Microbiology, University of Pavia, Via Ferrata 1, 27100 Pavia (Italy); Coutard, Bruno [Architecture et Fonction des Macromolécules Biologiques, UMR 6098 CNRS et Université Aix-Marseille I et II, ESIL, Campus de Luminy, 13288 Marseille CEDEX 09 (France); Forrester, Naomi L.; Gould, Ernest [Centre for Ecology and Hydrology (formerly Institute of Virology), Mansfield Road, Oxford OX1 3SR (United Kingdom); Canard, Bruno [Architecture et Fonction des Macromolécules Biologiques, UMR 6098 CNRS et Université Aix-Marseille I et II, ESIL, Campus de Luminy, 13288 Marseille CEDEX 09 (France); Mattevi, Andrea, E-mail: mattevi@ipvgen.unipv.it [Department of Genetics and Microbiology, University of Pavia, Via Ferrata 1, 27100 Pavia (Italy)

    2007-03-01

    Kokobera virus is a mosquito-borne flavivirus belonging, like West Nile virus, to the Japanese encephalitis virus serocomplex. Crystals of the Kokobera virus helicase domain were obtained by the hanging-drop vapour-diffusion method and exhibit a diffraction limit of 2.3 Å. Kokobera virus is a mosquito-borne flavivirus belonging, like West Nile virus, to the Japanese encephalitis virus serocomplex. The flavivirus genus is characterized by a positive-sense single-stranded RNA genome. The unique open reading frame of the viral RNA is transcribed and translated as a single polyprotein which is post-translationally cleaved to yield three structural and seven nonstructural proteins, one of which is the NS3 gene that encodes a C-terminal helicase domain consisting of 431 amino acids. Helicase inhibitors are potential antiviral drugs as the helicase is essential to viral replication. Crystals of the Kokobera virus helicase domain were obtained by the hanging-drop vapour-diffusion method. The crystals belong to space group P3{sub 1}21 (or P3{sub 2}21), with unit-cell parameters a = 88.6, c = 138.6 Å, and exhibit a diffraction limit of 2.3 Å.

  1. Niles Named To Head Virginia Tech's Newest College

    OpenAIRE

    Hincker, Lawrence

    2003-01-01

    Jerry Niles, interim dean of Virginia Tech's College of Human Sciences and Education and the college's former associate dean for innovation, graduate studies, and research, has been named dean of the university's newest college following an in-house search that began in January. Niles will assume the helm of the college, which will merge the College of Human Sciences and Education with the liberal arts departments in the current College of Arts and Sciences. His appointment is effective March...

  2. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt

    OpenAIRE

    Ayman Mohamed Megahed; Hesham Dahshan; Abd-El-Kader, Mahdy A.; Amr Mohamed Mohamed Abd-Elall; Mariam Hassan Elbana; Ehab Nabawy; Mahmoud, Hend A.

    2015-01-01

    Ten polychlorinated biphenyl (PCB) congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD). PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB cong...

  3. Hydrology and forests in the Blue Nile basin

    OpenAIRE

    Gebrehiwot, Solomon Gebreyohannis

    2012-01-01

    Forest cover change is considered a major cause of water scarcity during the dry season in the Blue Nile River Basin of Ethiopia, which is part of the Nile River system. However, this is an over-simplification of the complex reality of forest and flow relationships, especially in the tropics. The objectives of this study were to explore the spatial relationship of land use and flow regime, detect temporal changes in the hydrological regime, determine changes in the forest cover, and summarize...

  4. Biology of Zika virus infection in human skin cells

    OpenAIRE

    Hamel, Rodolphe; Dejarnac, Ophélie; Wichit, Sineewanlaya; Ekchariyawat, Peeraya; Neyret, Aymeric; Luplertlop, Natthanej; Perera-Lecoin, Manuel; Surasombatpattana, Pornapat; Talignani, Loïc; Thomas, Frédéric; Cao-Lormeau, Van-Mai; Choumet, Valérie; Briant, Laurence; Desprès, Philippe; Amara, Ali

    2015-01-01

    Zika virus (ZIKV) is an emerging arbovirus of the Flaviviridae family, which includes dengue, West Nile, yellow fever, and Japanese encephalitis viruses, that causes a mosquito-borne disease transmitted by the Aedes genus, with recent outbreaks in the South Pacific. Here we examine the importance of human skin in the entry of ZIKV and its contribution to the induction of antiviral immune responses. We show that human dermal fibroblasts, epidermal keratinocytes, and immature dendritic cells ar...

  5. Issues and challenges in spatial and temporal water allocation in the Nile Delta

    NARCIS (Netherlands)

    Wolters, Wouter; Smit, Robert; El-Din, Mohamed Nour; Ahmed, Eman Sayed; Froebrich, Jochen; Ritzema, Henk

    2016-01-01

    "Egypt is a gift of the Nile," wrote Herodotus, and indeed, without the Nile there would be no Egypt as the world knows it. Egypt is mainly dependent on the flow in the Nile River (with an agreed share of 55.5 BCM) and it receives about 1.3 BCM rainfall annually (mainly along the north coast). Th

  6. Targeting Host Factors to Treat West Nile and Dengue Viral Infections

    Directory of Open Access Journals (Sweden)

    Manoj N. Krishnan

    2014-02-01

    Full Text Available West Nile (WNV and Dengue (DENV viruses are major arboviral human pathogens belonging to the genus Flavivirus. At the current time, there are no approved prophylactics (e.g., vaccines or specific therapeutics available to prevent or treat human infections by these pathogens. Due to their minimal genome, these viruses require many host molecules for their replication and this offers a therapeutic avenue wherein host factors can be exploited as treatment targets. Since several host factors appear to be shared by many flaviviruses the strategy may result in pan-flaviviral inhibitors and may also attenuate the rapid emergence of drug resistant mutant viruses. The scope of this strategy is greatly enhanced by the recent en masse identification of host factors impacting on WNV and DENV infection. Excellent proof-of-principle experimental demonstrations for host-targeted control of infection and infection-induced pathogenesis have been reported for both WNV and DENV. These include exploiting not only those host factors supporting infection, but also targeting host processes contributing to pathogenesis and innate immune responses. While these early studies validated the host-targeting approach, extensive future investigations spanning a range of aspects are needed for a successful deployment in humans.

  7. Impact of the Sudd wetland on the Nile hydroclimatology

    Science.gov (United States)

    Mohamed, Y. A.; van den Hurk, B. J. J. M.; Savenije, H. H. G.; Bastiaanssen, W. G. M.

    2005-08-01

    Large evaporation occurs over the Sudd wetland, a huge swamp located on the upper Nile. Historically, water resources planners have had the intention to reduce the Sudd evaporation by shortcut channels (e.g., Jonglei canal). The question is: What is the effect of draining the Sudd wetland on the regional water cycle and on the Nile water flow? A regional climate model has been applied to the Nile Basin, with a special modification to include routing of the Nile flood over the Sudd. The impact of the wetland on the Nile hydroclimatology has been studied by comparing two model scenarios: the present climatology and a drained Sudd scenario. The results indicate that draining the entire Sudd has negligible impact on the regional water cycle owing to the relatively small area covered by the wetland. The runoff gain would then be up to ~36 Gm3 yr-1. However, the impact on the microclimate is large. The relative humidity will drop by 30-40% during the dry season, and temperature will rise by 4°-6°C. The impact during the wet season is small.

  8. The radiosensitivity of nile tilapia (Oreochromis niloticus) fingerlings

    International Nuclear Information System (INIS)

    The nile tilapia (Oreochromis niloticus), a very popular fish commercially in the Philippines, was studied to determine its radiosensitivity and to see its potential as a biological indicator in aquatic ecosystems. Nile tilapia was seen to be radiosensitive. The fish were exposed to gamma-irradiation and chromosomal aberrations were induced. The various types of aberrations seen were chromatid gaps, chromosome gaps, chromatid fragments, dicentric rings, fusions, despiralizations and translocations. Among the aberrations observed, dicentric rings, fusions and chromosome gaps were strongly correlated with dosage, with only the dicentric rings increasing steadily with increasing dosage. In the course of the study, the lethal dosage50 for nile tilapia with 18 days was determined and it was observed at 2.0 krad. The modal chromosome number was also established at 2n=44 with a karyotype exhibiting 22 pairs of acrocentric chromosomes with 2 pairs of marker chromosomes present. (Author)

  9. Sediment balances in the Blue Nile River Basin

    Institute of Scientific and Technical Information of China (English)

    Yasir SAALI; Alessandra CROSATO; Yasir AMOHAMED; Seifeldin HABDALLA; Nigel GWRIGHT

    2014-01-01

    Rapid population growth in the upper Blue Nile basin has led to fast land-use changes from natural forest to agricultural land. This resulted in speeding up the soil erosion process in the highlands and increasing sedimentation further downstream in reservoirs and irrigation canals. At present, several dams are planned across the Blue Nile River in Ethiopia and the Grand Ethiopian Renaissance Dam is currently under construction near the border with Sudan. This will be the largest hydroelectric power plant in Africa. The objective of this paper is to quantify the river flows and sediment loads along the Blue Nile River network. The Soil and Water Assessment Tool was used to estimate the water flows from un-gauged sub-basins. To assess model performance, the estimated sediment loads were compared to the measured ones at selected locations. For the gauged sub-basins, water flows and sediment loads were derived from the available flow and sediment data. To fill in knowledge gaps, this study included a field survey in which new data on suspended solids and flow discharge were collected along the Blue Nile and on a number of tributaries. The comparison between the results of this study and previous estimates of the sediment load of the Blue Nile River at El Deim, near the Ethiopian Sudanese border, show that the sediment budgets have the right order of magnitude, although some uncertainties remain. This gives confidence in the results of this study providing the first sediment balance of the entire Blue Nile catchment at the sub-basin scale.

  10. Hydrological characterization of watersheds in the Blue Nile Basin

    OpenAIRE

    S. G. Gebrehiwot; Ilstedt, U.; Gärdenas, A. I.; Bishop, K.

    2010-01-01

    We made a hydrological characterization of 32 watersheds (31–4350 km2) in the Blue Nile Basin, using data from a study of water and land resources in the Blue Nile Basin, Ethiopia published in 1964 by the US Bureau of Reclamation (USBR). The USBR document contains data on flow, climate, topography, geology, soil type, and land use for the period from 1959 to 1963. The aim of the study was to identify which combination of watershed variables best explain the variati...

  11. [Two imported cases of West Nile fever in Denmark].

    Science.gov (United States)

    Knudsen, Troels Bygum; Wilcke, Jon Torgny R; Andersen, Ove

    2003-05-01

    In the light of the current American epidemic, and since West Nile fever (WNF) has never previously been reported in Denmark, we describe two cases imported from Israel and Canada, respectively. WNF was diagnosed in a 46-year-old Danish tourist returning from Israel and a visiting 73-year-old Canadian citizen with Danish ancestry. The former manifested itself clinically as a mild flu-like illness, the latter as serious infection of the central nervous system. Thus, in addition to representing a rare case of West Nile encephalitis, it also constitutes one of the first reported cases of human infection of Canadian origin. PMID:12795078

  12. Bispidine-Amino Acid Conjugates Act as a Novel Scaffold for the Design of Antivirals That Block Japanese Encephalitis Virus Replication

    OpenAIRE

    Haridas, V.; Rajgokul, Kullampalayam Shanmugam; Sadanandan, Sandhya; Agrawal, Tanvi; Sharvani, Vats; M V S Gopalakrishna; M B Bijesh; Kumawat, Kanhaiya Lal; Basu, Anirban; Medigeshi, Guruprasad R.

    2013-01-01

    Background Japanese encephalitis virus (JEV) is a major cause of viral encephalitis in South and South-East Asia. Lack of antivirals and non-availability of affordable vaccines in these endemic areas are a major setback in combating JEV and other closely related viruses such as West Nile virus and dengue virus. Protein secondary structure mimetics are excellent candidates for inhibiting the protein-protein interactions and therefore serve as an attractive tool in drug development. We synthesi...

  13. An Integrated Hydrological and Water Management Study of the Entire Nile River System - Lake Victoria to Nile Delta

    Science.gov (United States)

    Habib, Shahid; Zaitchik, Benjamin; Alo, Clement; Ozdogan, Mutlu; Anderson, Martha; Policelli, Fritz

    2011-01-01

    The Nile basin River system spans 3 million km(exp 2) distributed over ten nations. The eight upstream riparian nations, Ethiopia, Eretria, Uganda, Rwanda, Burundi, Congo, Tanzania and Kenya are the source of approximately 86% of the water inputs to the Nile, while the two downstream riparian countries Sudan and Egypt, presently rely on the river's flow for most of the their needs. Both climate and agriculture contribute to the complicated nature of Nile River management: precipitation in the headwaters regions of Ethiopia and Lake Victoria is variable on a seasonal and inter-annual basis, while demand for irrigation water in the arid downstream region is consistently high. The Nile is, perhaps, one of the most difficult trans-boundary water issue in the world, and this study would be the first initiative to combine NASA satellite observations with the hydrologic models study the overall water balance in a to comprehensive manner. The cornerstone application of NASA's Earth Science Research Results under this project are the NASA Land Data Assimilation System (LDAS) and the USDA Atmosphere-land Exchange Inverse (ALEXI) model. These two complementary research results are methodologically independent methods for using NASA observations to support water resource analysis in data poor regions. Where an LDAS uses multiple sources of satellite data to inform prognostic simulations of hydrological process, ALEXI diagnoses evapotranspiration and water stress on the basis of thermal infrared satellite imagery. Specifically, this work integrates NASA Land Data Assimilation systems into the water management decision support systems that member countries of the Nile Basin Initiative (NBI) and Regional Center for Mapping of Resources for Development (RCMRD, located in Nairobi, Kenya) use in water resource analysis, agricultural planning, and acute drought response to support sustainable development of Nile Basin water resources. The project is motivated by the recognition that

  14. Companion Animals as a Source of Viruses for Human Beings and Food Production Animals.

    Science.gov (United States)

    Reperant, L A; Brown, I H; Haenen, O L; de Jong, M D; Osterhaus, A D M E; Papa, A; Rimstad, E; Valarcher, J-F; Kuiken, T

    2016-07-01

    Companion animals comprise a wide variety of species, including dogs, cats, horses, ferrets, guinea pigs, reptiles, birds and ornamental fish, as well as food production animal species, such as domestic pigs, kept as companion animals. Despite their prominent place in human society, little is known about the role of companion animals as sources of viruses for people and food production animals. Therefore, we reviewed the literature for accounts of infections of companion animals by zoonotic viruses and viruses of food production animals, and prioritized these viruses in terms of human health and economic importance. In total, 138 virus species reportedly capable of infecting companion animals were of concern for human and food production animal health: 59 of these viruses were infectious for human beings, 135 were infectious for food production mammals and birds, and 22 were infectious for food production fishes. Viruses of highest concern for human health included hantaviruses, Tahyna virus, rabies virus, West Nile virus, tick-borne encephalitis virus, Crimean-Congo haemorrhagic fever virus, Aichi virus, European bat lyssavirus, hepatitis E virus, cowpox virus, G5 rotavirus, influenza A virus and lymphocytic choriomeningitis virus. Viruses of highest concern for food production mammals and birds included bluetongue virus, African swine fever virus, foot-and-mouth disease virus, lumpy skin disease virus, Rift Valley fever virus, porcine circovirus, classical swine fever virus, equine herpesvirus 9, peste des petits ruminants virus and equine infectious anaemia virus. Viruses of highest concern for food production fishes included cyprinid herpesvirus 3 (koi herpesvirus), viral haemorrhagic septicaemia virus and infectious pancreatic necrosis virus. Of particular concern as sources of zoonotic or food production animal viruses were domestic carnivores, rodents and food production animals kept as companion animals. The current list of viruses provides an objective

  15. Zika Virus in an American Recreational Traveler.

    Science.gov (United States)

    Summers, Dyan J; Acosta, Rebecca Wolfe; Acosta, Alberto M

    2015-01-01

    We report the case of a 48-year-old American traveler who presented to our clinic with diffuse rash, malaise, fatigue, fever, arthralgia, low back pain, and bilateral exudative conjunctivitis. The patient had an extensive vaccination and travel history: most notable for prior receipt of yellow fever vaccine; extensive travel or residence in areas endemic for dengue, chikungunya, and West Nile virus; and recent travel to French Polynesia. Clinical and laboratory findings were consistent with Zika virus (ZIKV) infection. Our report highlights the need to include ZIKV in the differential diagnosis, especially in febrile patients with a rash returning from endemic areas. PMID:25996909

  16. Flaviviruses in Europe: Complex Circulation Patterns and Their Consequences for the Diagnosis and Control of West Nile Disease

    Directory of Open Access Journals (Sweden)

    Elsa Jourdain

    2013-11-01

    Full Text Available In Europe, many flaviviruses are endemic (West Nile, Usutu, tick-borne encephalitis viruses or occasionally imported (dengue, yellow fever viruses. Due to the temporal and geographical co-circulation of flaviviruses in Europe, flavivirus differentiation by diagnostic tests is crucial in the adaptation of surveillance and control efforts. Serological diagnosis of flavivirus infections is complicated by the antigenic similarities among the Flavivirus genus. Indeed, most flavivirus antibodies are directed against the highly immunogenic envelope protein, which contains both flavivirus cross-reactive and virus-specific epitopes. Serological assay results should thus be interpreted with care and confirmed by comparative neutralization tests using a panel of viruses known to circulate in Europe. However, antibody cross-reactivity could be advantageous in efforts to control emerging flaviviruses because it ensures partial cross-protection. In contrast, it might also facilitate subsequent diseases, through a phenomenon called antibody-dependent enhancement mainly described for dengue virus infections. Here, we review the serological methods commonly used in WNV diagnosis and surveillance in Europe. By examining past and current epidemiological situations in different European countries, we present the challenges involved in interpreting flavivirus serological tests and setting up appropriate surveillance programs; we also address the consequences of flavivirus circulation and vaccination for host immunity.

  17. Viruses in reptiles

    Directory of Open Access Journals (Sweden)

    Ariel Ellen

    2011-09-01

    Full Text Available Abstract The etiology of reptilian viral diseases can be attributed to a wide range of viruses occurring across different genera and families. Thirty to forty years ago, studies of viruses in reptiles focused mainly on the zoonotic potential of arboviruses in reptiles and much effort went into surveys and challenge trials of a range of reptiles with eastern and western equine encephalitis as well as Japanese encephalitis viruses. In the past decade, outbreaks of infection with West Nile virus in human populations and in farmed alligators in the USA has seen the research emphasis placed on the issue of reptiles, particularly crocodiles and alligators, being susceptible to, and reservoirs for, this serious zoonotic disease. Although there are many recognised reptilian viruses, the evidence for those being primary pathogens is relatively limited. Transmission studies establishing pathogenicity and cofactors are likewise scarce, possibly due to the relatively low commercial importance of reptiles, difficulties with the availability of animals and permits for statistically sound experiments, difficulties with housing of reptiles in an experimental setting or the inability to propagate some viruses in cell culture to sufficient titres for transmission studies. Viruses as causes of direct loss of threatened species, such as the chelonid fibropapilloma associated herpesvirus and ranaviruses in farmed and wild tortoises and turtles, have re-focused attention back to the characterisation of the viruses as well as diagnosis and pathogenesis in the host itself. 1. Introduction 2. Methods for working with reptilian viruses 3. Reptilian viruses described by virus families 3.1. Herpesviridae 3.2. Iridoviridae 3.2.1 Ranavirus 3.2.2 Erythrocytic virus 3.2.3 Iridovirus 3.3. Poxviridae 3.4. Adenoviridae 3.5. Papillomaviridae 3.6. Parvoviridae 3.7. Reoviridae 3.8. Retroviridae and inclusion body disease of Boid snakes 3.9. Arboviruses 3.9.1. Flaviviridae 3

  18. Environmental color affects Nile tilapia reproduction

    Directory of Open Access Journals (Sweden)

    Volpato G.L.

    2004-01-01

    Full Text Available We investigated the effects of environmental color on the reproductive behavior of Nile tilapia, Oreochromis niloticus. Two environmental colors were tested by covering the aquarium (60 x 60 x 40 cm with white (12 groups or blue (13 groups cellophane and observing reproductive behavior in groups of 2 males (10.27 ± 0.45 cm and 3 females (10.78 ± 0.45 cm each. After assignment to the respective environmental color (similar luminosity = 100 to 120 Lux, the animals were observed until reproduction (identified by eggs in the female's mouth or up to 10 days after the first nest building. Photoperiod was from 6:00 h to 18:00 h every day. Food was offered in excess once a day and water quality was similar among aquaria. Daily observations were made at 8:00, 11:00, 14:00 and 17:00 h regarding: a latency to the first nest, b number of nests, c gravel weight removed (the male excavates the nest in the bottom of the aquarium, d nest area, and e mouthbrooding incubation (indication of reproduction. The proportion of reproducing fish was significantly higher (6 of 13 in the group exposed to the blue color compared the group exposed to the white color (1 of 12; Goodman's test of proportions. Moreover, males under blue light removed significantly larger masses of gravel (blue = 310.70 ± 343.50 g > white = 130.38 ± 102.70 g; P = 0.01 and constructed wider nests (blue = 207.93 ± 207.80 cm² > white = 97.68 ± 70.64 cm²; P = 0.03 than the control (white. The other parameters did not differ significantly between light conditions. We concluded that reproduction in the presence of blue light was more frequent and intense than in the presence of white light.

  19. Human Streptococcus agalactiae Isolate in Nile Tilapia (Oreochromis niloticus)

    OpenAIRE

    Evans, Joyce J.; Klesius, Phillip H.; Pasnik, David J.; Bohnsack, John F.

    2009-01-01

    Streptococcus agalactiae, the Lancefield group B streptococcus (GBS) long recognized as a mammalian pathogen, is an emerging concern with regard to fish. We show that a GBS serotype Ia multilocus sequence type ST-7 isolate from a clinical case of human neonatal meningitis caused disease and death in Nile tilapia (Oreochromis niloticus).

  20. Heritability of cold tolerance in Nile tilapia, Oreochromis niloticus, juveniles

    NARCIS (Netherlands)

    Charo-Karisa, H.; Rezk, M.A.; Bovenhuis, H.; Komen, J.

    2005-01-01

    The inability of tilapia to tolerate low temperatures is of major economic concern as it reduces their growing season and leads to over winter mortality. In this study, cold tolerance of juvenile Nile tilapia, Oreochromis niloticus, was investigated and heritability estimates obtained. A total of 80

  1. Clinical sentinel surveillance of equine West Nile fever, Spain

    DEFF Research Database (Denmark)

    Saegerman, C.; Alba-Casals, A.; García-Bocanegra, I.;

    2016-01-01

    West Nile fever (WNF) is a viral zoonotic infection caused by a mosquito-borne flavivirus of the Flaviviridae family. According to a comparative study, the passive surveillance of horses by equine veterinarians appeared to be the most cost-effective system in the European context of WNF. Clinical...

  2. Agricultural Model for the Nile Basin Decision Support System

    Science.gov (United States)

    van der Bolt, Frank; Seid, Abdulkarim

    2014-05-01

    To analyze options for increasing food supply in the Nile basin the Nile Agricultural Model (AM) was developed. The AM includes state-of-the-art descriptions of biophysical, hydrological and economic processes and realizes a coherent and consistent integration of hydrology, agronomy and economics. The AM covers both the agro-ecological domain (water, crop productivity) and the economic domain (food supply, demand, and trade) and allows to evaluate the macro-economic and hydrological impacts of scenarios for agricultural development. Starting with the hydrological information from the NileBasin-DSS the AM calculates the available water for agriculture, the crop production and irrigation requirements with the FAO-model AquaCrop. With the global commodity trade model MAGNET scenarios for land development and conversion are evaluated. The AM predicts consequences for trade, food security and development based on soil and water availability, crop allocation, food demand and food policy. The model will be used as a decision support tool to contribute to more productive and sustainable agriculture in individual Nile countries and the whole region.

  3. Breeding for improved production of Nile tilapia (Oreochromis niloticus L.)

    NARCIS (Netherlands)

    Rutten, M.J.M.

    2005-01-01

    The aim of this thesis was to generate knowledge that supports the design of breeding programs for Nile tilapia targeting genetic improvement of body weight and fillet yield to serve the European market. To this end, both the genetic variation and the performance levels of different strains of tilap

  4. The modern Nile sediment system: Processes and products

    Science.gov (United States)

    Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Vezzoli, Giovanni; El Kammar, Ahmed

    2015-12-01

    We trace compositional changes of Nile sediments for 7400 km, from their sources in equatorial rift highlands of Burundi and Rwanda to their sink in the Mediterranean Sea. All chemical and physical controls on sediment petrography, mineralogy and geochemistry, including weathering, grain-size, hydraulic sorting, mechanical breakdown, anthropic impact, mixing and recycling are investigated in detail. The Nile course is controlled along its entire length by the East African-Red Sea Rift. In this anorogenic setting, detritus is derived in various proportions from volcanic fields associated with tectonic extension (Anorogenic Volcanic provenance) and from igneous, metamorphic and sedimentary rocks uplifted on the rift shoulders or exposed on the craton (Continental Block provenance). The entire spectrum of such detrital signatures is displayed in the Nile catchment. Volcaniclastic Atbara sand is generated by focused erosion of the Ethiopian basaltic plateau in semiarid climate, whereas quartzose White Nile sand reflects low erosion rates, extensive weathering and sediment trapping in lakes and swamps at equatorial to subequatorial latitudes. In the main Nile, as in its main tributary the Blue Nile, suspended load is volcaniclastic, whereas feldspatho-quartzose bedload is derived largely from basement sources, with fine to medium-grained eolian sand added along the lower course. Mixing of detrital populations with different provenance and grain size is reflected in diverse violations of settling-equivalence relationships in fluvial and deltaic sediments. Sediment delivery from Sudan has been cut off after closure of the Aswan High Dam and accelerated erosion of deltaic cusps is leading to local formation of placer lags dominated by ultradense Fe-Ti-Cr oxides, but mineralogical changes caused by man's radical modification of fluvial regimes have been minor so far. In beaches of Sinai, Gaza and Israel, the Nile volcaniclastic trace gets progressively diluted by quartzose

  5. Host competence and helicase activity differences exhibited by West Nile viral variants expressing NS3-249 amino acid polymorphisms.

    Directory of Open Access Journals (Sweden)

    Stanley A Langevin

    Full Text Available A single helicase amino acid substitution, NS3-T249P, has been shown to increase viremia magnitude/mortality in American crows (AMCRs following West Nile virus (WNV infection. Lineage/intra-lineage geographic variants exhibit consistent amino acid polymorphisms at this locus; however, the majority of WNV isolates associated with recent outbreaks reported worldwide have a proline at the NS3-249 residue. In order to evaluate the impact of NS3-249 variants on avian and mammalian virulence, multiple amino acid substitutions were engineered into a WNV infectious cDNA (NY99; NS3-249P and the resulting viruses inoculated into AMCRs, house sparrows (HOSPs and mice. Differential viremia profiles were observed between mutant viruses in the two bird species; however, the NS3-249P virus produced the highest mean peak viral loads in both avian models. In contrast, this avian modulating virulence determinant had no effect on LD50 or the neurovirulence phenotype in the murine model. Recombinant helicase proteins demonstrated variable helicase and ATPase activities; however, differences did not correlate with avian or murine viremia phenotypes. These in vitro and in vivo data indicate that avian-specific phenotypes are modulated by critical viral-host protein interactions involving the NS3-249 residue that directly influence transmission efficiency and therefore the magnitude of WNV epizootics in nature.

  6. Causal links between Nile floods and eastern Mediterranean sapropel formation during the past 125 kyr confirmed by OSL and radiocarbon dating of Blue and White Nile sediments

    Science.gov (United States)

    Williams, M. A. J.; Duller, G. A. T.; Williams, F. M.; Woodward, J. C.; Macklin, M. G.; El Tom, O. A. M.; Munro, R. N.; El Hajaz, Y.; Barrows, T. T.

    2015-12-01

    It has long been hypothesised that beds of highly organic mud or sapropels seen in marine sediment cores retrieved from the floor of the eastern Mediterranean accumulated during times of high Nile fluvial discharge. Our recent fieldwork in the valleys of the Blue Nile, the White Nile and the main Nile has for the first time revealed a sequence of extreme flood episodes synchronous with sapropel units S5 (124 kyr), S4 (102 kyr), S3 (81 kyr), S2 (55 kyr) and S1 (13.5-6.5 kyr). There are more weakly defined links with Nile floods and sapropel units S9 (240 kyr), S8 (217 kyr), S7 (195 kyr), S6 (172 kyr), but the dating error terms are too large to allow us to be too definite. During times of extreme floods over the past 125 kyr, wide distributary channels of the Blue Nile flowed across the Gezira alluvial fan in central Sudan and transported a bed load of sand and gravel into the lower White Nile valley. The sands were reworked by wind to form source-bordering dunes, all of which contain heavy minerals of Ethiopian provenance. These source-bordering dunes were active at 115-105 kyr, 60 kyr and 12-7 kyr, all times of extreme Blue Nile floods. The flood and dune sediments were dated using a combination of optically stimulated luminescence (OSL) and radiocarbon analyses. The Quaternary record of Nile floods discussed here shows a precessional signal and reflects episodes of stronger summer monsoon and more northerly seasonal movement of the ITCZ, linked to times of higher insolation in northern tropical latitudes. Progressive aggradation of Holocene Nile channels in northern Sudan has had a profound influence upon human settlement in the last 8 kyr.

  7. Abundance, distribution and population trends of Nile crocodile (Crocodylus niloticus) in Gonarezhou National Park, Zimbabwe

    OpenAIRE

    Zisadza-Gandiwa, P.; Gandiwa, E.; Jakarasi, J.; Westhuizen, van der, H.; Muvengwi, J.

    2013-01-01

    The Nile crocodile (Crocodylus niloticus) is an iconic or keystone species in many aquatic ecosystems. In order to understand the abundance, distribution, and population trends of Nile crocodiles in Gonarezhou National Park (GNP), southeastern Zimbabwe, we carried out 4 annual aerial surveys, using a Super Cub aircraft, along 3 major rivers, namely, Save, Runde and Mwenezi, between 2008 and 2011. Our results show that Runde River was characterised by a significant increase in Nile crocodile a...

  8. Heartland Virus

    Science.gov (United States)

    ... Vector-Borne Diseases (DVBD) NCEZID Share Compartir Heartland virus On this Page What is Heartland virus? How ... Do I Need to Know? What is Heartland virus? Heartland virus belongs to a family of viruses ...

  9. Spread of Zika virus: The key role of mosquito vector control

    OpenAIRE

    Giovanni Benelli

    2016-01-01

    Mosquitoes (Diptera: Culicidae) represent a key threat for millions of humans and animals worldwide, since they act as vectors for important parasites and pathogens, including malaria, filariasis and a wide number of arboviruses. The recent outbreaks of Zika virus infections occurring in South America, Central America, and the Caribbean, represent the most recent four arrivals of important arboviruses in the western hemisphere, over the last 20 years, namely dengue, West Nile virus, and chiku...

  10. Vector Borne Infections in Italy: Results of the Integrated Surveillance System for West Nile Disease in 2013

    Directory of Open Access Journals (Sweden)

    Christian Napoli

    2015-01-01

    Full Text Available The epidemiology of West Nile disease (WND is influenced by multiple ecological factors and, therefore, integrated surveillance systems are needed for early detecting the infection and activating consequent control actions. As different animal species have different importance in the maintenance and in the spread of the infection, a multispecies surveillance approach is required. An integrated and comprehensive surveillance system is in place in Italy aiming at early detecting the virus introduction, monitoring the possible infection spread, and implementing preventive measures for human health. This paper describes the integrated surveillance system for WND in Italy, which incorporates data from veterinary and human side in order to evaluate the burden of infection in animals and humans and provide the public health authorities at regional and national levels with the information needed for a fine tune response.

  11. The Holocene Geoarchaeology of the Desert Nile in Northern Sudan

    Science.gov (United States)

    Woodward, Jamie; Macklin, Mark; Spencer, Neal; Welsby, Derek; Dalton, Matthew; Hay, Sophie; Hardy, Andrew

    2016-04-01

    Invited Paper Forty years ago Colin Renfrew declared that "every archaeological problem starts as a problem in geoarchaeology" (Renfrew, 1976 p. 2). With this assertion in mind, this paper draws upon the findings from field research in two sectors of the Nile Valley of Northern Sudan dedicated to the exploration of human-environment interactions during the middle and late Holocene. This part of the Nile corridor contains a rich cultural record and an exceptionally well preserved Holocene fluvial archive. A distinctive feature of these records is the variety of evidence for interaction between desert and river over a range of spatial and temporal scales. This interaction presented both challenges and opportunities for its ancient inhabitants. This paper will present evidence for large-scale landscape changes driven by shifts in global climate. It will also show how we have integrated the archaeological and geological records in the Northern Dongola Reach and at Amara West - where long-term field projects led by archaeologists from the British Museum have recognised the importance of a sustained commitment to interdisciplinary research to achieve a fully integrated geoarchaeological approach across a range of scales. The former project is a large-scale landscape survey with multiple sites across an 80 km reach of the Nile whilst the latter has a strong focus on a single New Kingdom town site and changes in its environmental setting. By combining multiple archaeological and geological datasets - and pioneering the use of OSL dating and strontium isotope analysis in the Desert Nile - we have developed a new understanding of human responses to Holocene climate and landscape change in this region. Renfrew, C. (1976) Archaeology and the earth sciences. In: D.A. Davidson and M.I. Shackley (eds) Geoarchaeology: Earth Science and the Past, Duckworth, London, 1-5.

  12. The resurgence of lymphatic filariasis in the Nile delta.

    OpenAIRE

    Harb, M.; Faris, R; Gad, A. M.; Hafez, O. N.; Ramzy, R.; Buck, A. A.

    1993-01-01

    A study of 325,000 residents of 314 villages in six governorates of the Nile delta area of Egypt revealed that the prevalence of lymphatic filariasis increased from 20% in 1991, especially in the governorates of Qalyubiya, Monufiya, Dakhaliya, and Giza. The distribution of the communites with endemic filariasis is focal. Clusters of villages with high prevalences are surrounded by others in which the disease is absent, although their environmental, social, and agricultural f...

  13. Spatio-Temporal Identification of Areas Suitable for West Nile Disease in the Mediterranean Basin and Central Europe.

    Directory of Open Access Journals (Sweden)

    Annamaria Conte

    Full Text Available West Nile virus (WNV is a mosquito-transmitted Flavivirus belonging to the Japanese encephalitis antigenic complex of the Flaviviridae family. Its spread in the Mediterranean basin and the Balkans poses a significant risk to human health and forces public health officials to constantly monitor the virus transmission to ensure prompt application of preventive measures. In this context, predictive tools indicating the areas and periods at major risk of WNV transmission are of paramount importance. Spatial analysis approaches, which use environmental and climatic variables to find suitable habitats for WNV spread, can enhance predictive techniques. Using the Mahalanobis Distance statistic, areas ecologically most suitable for sustaining WNV transmission were identified in the Mediterranean basin and Central Europe. About 270 human and equine clinical cases notified in Italy, Greece, Portugal, Morocco, and Tunisia, between 2008 and 2012, have been considered. The environmental variables included in the model were altitude, slope, night time Land Surface Temperature, Normalized Difference Vegetation Index, Enhanced Vegetation Index, and daily temperature range. Seasonality of mosquito population has been modelled and included in the analyses to produce monthly maps of suitable areas for West Nile Disease. Between May and July, the most suitable areas are located in Tunisia, Libya, Egypt, and North Cyprus. Summer/Autumn months, particularly between August and October, characterize the suitability in Italy, France, Spain, the Balkan countries, Morocco, North Tunisia, the Mediterranean coast of Africa, and the Middle East. The persistence of suitable conditions in December is confined to the coastal areas of Morocco, Tunisia, Libya, Egypt, and Israel.

  14. Socioeconomic dynamics of water quality in the Egyptian Nile

    Science.gov (United States)

    Malik, Maheen; Nisar, Zainab; Karakatsanis, Georgios

    2016-04-01

    The Nile River remains the most important source of freshwater for Egypt as it accounts for nearly all of the country's drinking and irrigation water. About 95% of the total population is accounted to live along the Banks of the Nile(1). Therefore, water quality deterioration in addition to general natural scarcity of water in the region(2) is the main driver for carrying out this study. What further aggravates this issue is the water conflict in the Blue Nile region. The study evaluates different water quality parameters and their concentrations in the Egyptian Nile; further assessing the temporal dynamics of water quality in the area with (a) the Environmental Kuznets Curve (EKC)(3) and (b) the Jevons Paradox (JP)(4) in order to identify water quality improvements or degradations using selected socioeconomic variables(5). For this purpose various environmental indicators including BOD, COD, DO, Phosphorus and TDS were plotted against different economic variables including Population, Gross Domestic Product (GDP), Annual Fresh Water Withdrawal and Improved Water Source. Mathematically, this was expressed by 2nd and 3rd degree polynomial regressions generating the EKC and JP respectively. The basic goal of the regression analysis is to model and highlight the dynamic trend of water quality indicators in relation to their established permissible limits, which will allow the identification of optimal future water quality policies. The results clearly indicate that the dependency of water quality indicators on socioeconomic variables differs for every indicator; while COD was above the permissible limits in all the cases despite of its decreasing trend in each case, BOD and phosphate signified increasing concentrations for the future, if they continue to follow the present trend. This could be an indication of rebound effect explained by the Jevons Paradox i.e. water quality deterioration after its improvement, either due to increase of population or intensification

  15. Tracing of the defunct Canopic Nile branch using geoelectrical resistivity data around Itay El-Baroud area, Nile Delta, Egypt

    International Nuclear Information System (INIS)

    Around the Nile Delta Branches, ancient settlements had been created and left their remains to be good witness for the paleoenvironment during the Holocene time. Therefore, tracing of the defunct Canopic branch and its distributaries as well as associated environments are of great importance. Using a Schlumberger electrode configuration, well-distributed 44 vertical electrical resistivity soundings were acquired. The 1D modelling technique was applied to estimate the depth and the apparent resistivity of the interpreted geoelectrical units. Then 2D inversion was applied for the same data set using the ABIC least-squares inversion scheme. The geoelectrical cross-sections and slice maps discriminate the Upper Quaternary sequence into three geoelectrical units. The Holocene Nile mud is represented by two units: the agricultural root zone (unit 1) that is underlain by relatively thick water-saturated mud (unit 2). The Upper Pleistocene sandy aquifer is represented by irregular surface (unit 3). Two generations of defunct channels were traced out. The older channels are characterized by low sinuosity compared with younger channels. This is probably attributed to river activity due to relatively low sea level and much higher Nile discharge. The system of younger channels is characterized by broad meanders, probably as a consequence of sea-level rise and decreased gradient since the Middle Holocene

  16. Water balance modeling of Upper Blue Nile catchments using a top-down approach

    NARCIS (Netherlands)

    Tekleab, S.; Uhlenbrook, S.; Mohamed, Y.; Savenije, H.H.G.; Temesgen, M.; Wenninger, J.

    2011-01-01

    The water balances of twenty catchments in the Upper Blue Nile basin have been analyzed using a top-down modeling approach based on Budyko’s hypotheses. The objective of this study is to obtain better understanding of water balance dynamics of upper Blue Nile catchments on annual and monthly time sc

  17. Edwardsiella ictaluri as the causative agent of mortality in cultured Nile tilapia

    Science.gov (United States)

    Edwardsiella ictaluri was consistently isolated from the spleens, livers, and head kidneys of diseased Nile tilapia Oreochromis niloticus from a farm experiencing mortality events in several culture ponds. We describe the first published outbreak of E. ictaluri–induced Edwardsiellosis in Nile tilapi...

  18. Complete Genome Sequence of Streptococcus agalactiae Strain S25 Isolated from Peritoneal Liquid of Nile Tilapia

    Science.gov (United States)

    Mainardi, Rafaella Menegheti; Lima Júnior, Edson Antônio; Ribeiro Júnior, Jose Carlos; Beloti, Vanerli; Carmo, Anderson Oliveira; Kalapothakis, Evanguedes; Gonçalves, Daniela Dib; Padua, Santiago Benites

    2016-01-01

    Streptococcus agalactiae (Lancefield group B; GBS) is one of the major pathogens in fish production, especially in Nile tilapia (Oreochromis niloticus). The genomic characteristics of GBS isolated from fish must be more explored. Thus, we present here the genome of GBS S25, isolated from Nile tilapia from Brazil. PMID:27491974

  19. Understanding Catchment Processes and Hydrological Modelling in the Abay/Upper Blue Nile Basin, Ethiopia

    NARCIS (Netherlands)

    Gebrekristos, S.T.

    2015-01-01

    The water resources in the Abay/Upper Blue Nile basin are the source of life for the several hundred million people living in the basin and further downstream. It provides more than 60% of the total Nile water. Intensive farming in unfavourable soils and slopes, overgrazing and soil erosion is among

  20. Complete Genome Sequence of Streptococcus agalactiae Strain S25 Isolated from Peritoneal Liquid of Nile Tilapia.

    Science.gov (United States)

    Mainardi, Rafaella Menegheti; Lima Júnior, Edson Antônio; Ribeiro Júnior, Jose Carlos; Beloti, Vanerli; Carmo, Anderson Oliveira; Kalapothakis, Evanguedes; Gonçalves, Daniela Dib; Padua, Santiago Benites; Pereira, Ulisses Pádua

    2016-01-01

    Streptococcus agalactiae (Lancefield group B; GBS) is one of the major pathogens in fish production, especially in Nile tilapia (Oreochromis niloticus). The genomic characteristics of GBS isolated from fish must be more explored. Thus, we present here the genome of GBS S25, isolated from Nile tilapia from Brazil. PMID:27491974

  1. Explaining and forecasting interannual variability in the flow of the Nile River

    Science.gov (United States)

    Siam, M. S.; Eltahir, E. A. B.

    2014-05-01

    The natural interannual variability in the flow of Nile River had a significant impact on the ancient civilizations and cultures that flourished on the banks of the river. This is evident from stories in the Bible and Koran, and from the numerous Nilometers discovered near ancient temples. Here, we analyze extensive data sets collected during the 20th century and define four modes of natural variability in the flow of Nile River, identifying a new significant potential for improving predictability of floods and droughts. Previous studies have identified a significant teleconnection between the Nile flow and the Eastern Pacific Ocean. El Niño-Southern Oscillation (ENSO) explains about 25% of the interannual variability in the Nile flow. Here, we identify, for the first time, a region in the southern Indian Ocean with similarly strong teleconnection to the Nile flow. Sea Surface Temperature (SST) in the region (50-80° E and 25-35° S) explains 28% of the interannual variability in the Nile flow. During those years with anomalous SST conditions in both Oceans, we estimate that indices of the SSTs in the Pacific and Indian Oceans can collectively explain up to 84% of the interannual variability in the flow of Nile. Building on these findings, we use classical Bayesian theorem to develop a new hybrid forecasting algorithm that predicts the Nile flow based on global models predictions of indices of the SST in the Eastern Pacific and Southern Indian Oceans.

  2. Abundance, distribution and population trends of Nile crocodile (Crocodylus niloticus) in Gonarezhou National Park, Zimbabwe

    NARCIS (Netherlands)

    Zisadza-Gandiwa, P.; Gandiwa, E.; Jakarasi, J.; Westhuizen, van der H.; Muvengwi, J.

    2013-01-01

    The Nile crocodile (Crocodylus niloticus) is an iconic or keystone species in many aquatic ecosystems. In order to understand the abundance, distribution, and population trends of Nile crocodiles in Gonarezhou National Park (GNP), southeastern Zimbabwe, we carried out 4 annual aerial surveys, using

  3. An insight into the sialotranscriptome of the West Nile mosquito vector, Culex tarsalis

    Directory of Open Access Journals (Sweden)

    Olson Kenneth E

    2010-01-01

    Full Text Available Abstract Background Saliva of adult female mosquitoes help sugar and blood feeding by providing enzymes and polypeptides that help sugar digestion, control microbial growth and counteract their vertebrate host hemostasis and inflammation. Mosquito saliva also potentiates the transmission of vector borne pathogens, including arboviruses. Culex tarsalis is a bird feeding mosquito vector of West Nile Virus closely related to C. quinquefasciatus, a mosquito relatively recently adapted to feed on humans, and the only mosquito of the genus Culex to have its sialotranscriptome so far described. Results A total of 1,753 clones randomly selected from an adult female C. tarsalis salivary glands (SG cDNA library were sequenced and used to assemble a database that yielded 809 clusters of related sequences, 675 of which were singletons. Primer extension experiments were performed in selected clones to further extend sequence coverage, allowing for the identification of 283 protein sequences, 80 of which code for putative secreted proteins. Conclusion Comparison of the C. tarsalis sialotranscriptome with that of C. quinquefasciatus reveals accelerated evolution of salivary proteins as compared to housekeeping proteins. The average amino acid identity among salivary proteins is 70.1%, while that for housekeeping proteins is 91.2% (P Aedes genus have been identified in C. tarsalis. Interestingly, a protein family so far unique to C. quinquefasciatus, with 30 genes, is also found in C. tarsalis, indicating it was not a specific C. quinquefasciatus acquisition in its evolution to optimize mammal blood feeding.

  4. Larvicidal Activity of Nerium oleander against Larvae West Nile Vector Mosquito Culex pipiens (Diptera: Culicidae)

    Science.gov (United States)

    El-Akhal, Fouad; Guemmouh, Raja; Ez Zoubi, Yassine; El Ouali Lalami, Abdelhakim

    2015-01-01

    Background. Outbreaks of the West Nile virus infection were reported in Morocco in 1996, 2003, and 2010. Culex pipiens was strongly suspected as the vector responsible for transmission. In the North center of Morocco, this species has developed resistance to synthetic insecticides. There is an urgent need to find alternatives to the insecticides as natural biocides. Objective. In this work, the insecticidal activity of the extract of the local plant Nerium oleander, which has never been tested before in the North center of Morocco, was studied on larval stages 3 and 4 of Culex pipiens. Methods. Biological tests were realized according to a methodology inspired from standard World Health Organization protocol. The mortality values were determined after 24 h of exposure and LC50 and LC90 values were calculated. Results. The extract had toxic effects on the larvae of culicid mosquitoes. The ethanolic extract of Nerium oleander applied against the larvae of Culex pipiens has given the lethal concentrations LC50 and LC90 in the order of 57.57 mg/mL and 166.35 mg/mL, respectively. Conclusion. This investigation indicates that N. oleander could serve as a potential larvicidal, effective natural biocide against mosquito larvae, particularly Culex pipiens. PMID:26640701

  5. Larvicidal Activity of Nerium oleander against Larvae West Nile Vector Mosquito Culex pipiens (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Fouad El-Akhal

    2015-01-01

    Full Text Available Background. Outbreaks of the West Nile virus infection were reported in Morocco in 1996, 2003, and 2010. Culex pipiens was strongly suspected as the vector responsible for transmission. In the North center of Morocco, this species has developed resistance to synthetic insecticides. There is an urgent need to find alternatives to the insecticides as natural biocides. Objective. In this work, the insecticidal activity of the extract of the local plant Nerium oleander, which has never been tested before in the North center of Morocco, was studied on larval stages 3 and 4 of Culex pipiens. Methods. Biological tests were realized according to a methodology inspired from standard World Health Organization protocol. The mortality values were determined after 24 h of exposure and LC50 and LC90 values were calculated. Results. The extract had toxic effects on the larvae of culicid mosquitoes. The ethanolic extract of Nerium oleander applied against the larvae of Culex pipiens has given the lethal concentrations LC50 and LC90 in the order of 57.57 mg/mL and 166.35 mg/mL, respectively. Conclusion. This investigation indicates that N. oleander could serve as a potential larvicidal, effective natural biocide against mosquito larvae, particularly Culex pipiens.

  6. Efficacy of Mosquito Traps for Collecting Potential West Nile Mosquito Vectors in a Natural Mediterranean Wetland

    DEFF Research Database (Denmark)

    Roiz, David; Roussel, Marion; Muñoz, Joaquin;

    2012-01-01

    Surveillance, research, and control of mosquito-borne diseases such asWest Nile virus require efficient methods for sampling mosquitoes. We compared the efficacy of BG-Sentinel and Centers for Disease Control and Prevention (CDC)-CO2 traps in terms of the abundances of host-seeking and blood......-fed female mosquitoes and the origin of mosquito bloodmeals. Our results indicate that BG-Sentinel traps that use CO2 and attractants are as effective as CDC-CO2 traps for Culex mosquito species, Ochlerotatus caspius, and they are also highly efficient at capturing Anopheles atroparvus host-seeking and blood......-fed females with or without CO2. The CDC-CO2 trap is the least efficient method for capturing blood-fed females. BG-Sentinel traps with attractants and CO2 were significantly better at capturing mosquitoes that had fed on mammals than the unbaited BG-Sentinel and CDC-CO2 traps in the cases of An. atroparvus...

  7. Water pollution in the Middle Nile Delta, Egypt: An environmental study

    Directory of Open Access Journals (Sweden)

    Samy I. El-Kowrany

    2016-09-01

    Full Text Available Water-borne diseases have been estimated to cause more than two million deaths and four billion cases of diarrhea annually. Water-borne pathogenic organisms include bacteria, protozoa, and viruses. Heavy metal contamination of water is also a potential threat to human health. This study aimed to detect contamination of potable water with protozoal and bacterial pathogens as well as heavy metals in Gharbiya governorate in the middle of the Nile Delta, Egypt. Therefore, this study was conducted on water samples from 3 different localities in Gharbiya governorate throughout the year 2014. Water samples (108 were collected from source, plant and tap water at the four seasons. Parasitological, bacteriological, and toxicological evaluation was carried out for all samples. Parasitological evaluation was done to detect protozoal contamination by conventional diagnostic staining techniques, immunofluorescence assay, and flow cytometry. The study identified the protozoal contaminants in water, and showed that flow cytometry positive results were more than the conventional staining. Also, the study identified bacterial fecal contamination of source water as well as heavy metal pollution in source water. Since the integration of flow cytometry could facilitate detection of Giardia cysts and Cryptosporidium oocysts in water samples, we strongly recommend its use as a routine for the detection of these pathogenic protozoa. Finally, Ongoing evaluation of drinking water is needed as well as formulation and implementation of an integrated plan to limit the contamination by pathogens and heavy metals.

  8. Induction of Epitope-Specific Neutralizing Antibodies against West Nile Virus▿

    Science.gov (United States)

    Oliphant, Theodore; Nybakken, Grant E.; Austin, S. Kyle; Xu, Qing; Bramson, Jonathan; Loeb, Mark; Throsby, Mark; Fremont, Daved H.; Pierson, Theodore C.; Diamond, Michael S.

    2007-01-01

    Previous studies have established that an epitope on the lateral ridge of domain III (DIII-lr) of West Nile virus (WNV) envelope (E) protein is recognized by strongly neutralizing type-specific antibodies. In contrast, an epitope against the fusion loop in domain II (DII-fl) is recognized by flavivirus cross-reactive antibodies with less neutralizing potential. Using gain- and loss-of-function E proteins and wild-type and variant WNV reporter virus particles, we evaluated the expression pattern and activity of antibodies against the DIII-lr and DII-fl epitopes in mouse and human serum after WNV infection. In mice, immunoglobulin M (IgM) antibodies to the DIII-lr epitope were detected at low levels at day 6 after infection. However, compared to IgG responses against other epitopes in DI and DII, which were readily detected at day 8, the development of IgG against DIII-lr epitope was delayed and did not appear consistently until day 15. This late time point is notable since almost all death after WNV infection in mice occurs by day 12. Nonetheless, at later time points, DIII-lr antibodies accumulated and comprised a significant fraction of the DIII-specific IgG response. In sera from infected humans, DIII-lr antibodies were detected at low levels and did not correlate with clinical outcome. In contrast, antibodies to the DII-fl were detected in all human serum samples and encompassed a significant percentage of the anti-E protein response. Our experiments suggest that the highly neutralizing DIII-lr IgG antibodies have little significant role in primary infection and that the antibody response of humans may be skewed toward the induction of cross-reactive, less-neutralizing antibodies. PMID:17715236

  9. Shifting sediment sources in the world's longest river: A strontium isotope record for the Holocene Nile

    Science.gov (United States)

    Woodward, Jamie; Macklin, Mark; Fielding, Laura; Millar, Ian; Spencer, Neal; Welsby, Derek; Williams, Martin

    2015-12-01

    We have reconstructed long-term shifts in catchment sediment sources by analysing, for the first time, the strontium (Sr) and neodymium (Nd) isotope composition of dated floodplain deposits in the Desert Nile. The sediment load of the Nile has been dominated by material from the Ethiopian Highlands for much of the Holocene, but tributary wadis and aeolian sediments in Sudan and Egypt have also made major contributions to valley floor sedimentation. The importance of these sources has shifted dramatically in response to global climate changes. During the African Humid Period, before c. 4.5 ka, when stronger boreal summer insolation produced much higher rainfall across North Africa, the Nile floodplain in northern Sudan shows a tributary wadi input of 40-50%. Thousands of tributary wadis were active at this time along the full length of the Saharan Nile in Egypt and Sudan. As the climate became drier after 4.5 ka, the valley floor shows an abrupt fall in wadi inputs and a stronger Blue Nile/Atbara contribution. In the arid New Kingdom and later periods, in palaeochannel fills on the margins of the valley floor, aeolian sediments replace wadi inputs as the most important secondary contributor to floodplain sedimentation. Our sediment source data do not show a measurable contribution from the White Nile to the floodplain deposits of northern Sudan over the last 8500 years. This can be explained by the distinctive hydrology and sediment delivery dynamics of the upper Nile basin. High strontium isotope ratios observed in delta and offshore records - that were previously ascribed to a stronger White Nile input during the African Humid Period - may have to be at least partly reassessed. Our floodplain Sr records also have major implications for bioarchaeologists who carry out Sr isotope-based investigations of ancient human remains in the Nile Valley because the isotopic signature of Nile floodplain deposits has shifted significantly over time.

  10. Nile behaviour and Late Palaeolithic humans in Upper Egypt during the Late Pleistocene

    Science.gov (United States)

    Vermeersch, Pierre M.; Van Neer, Wim

    2015-12-01

    The reconstruction of the environment and the human population history of the Nile Valley during the Late Pleistocene have received a lot of attention in the literature thus far. There seems to be a consensus that during MIS2 extreme dry conditions prevailed over north-eastern Africa, which was apparently not occupied by humans. The Nile Valley seems to be an exception; numerous field data have been collected suggesting an important population density in Upper Egypt during MIS2. The occupation remains are often stratified in, or at least related to, aeolian and Nile deposits at some elevation above the present-day floodplain. They are rich in lithics and animal bones, mainly fish, illustrating the exploitation of the Nile Valley by the Late Palaeolithic inhabitants. The fluvial processes active during that period have traditionally been interpreted as a continuously rising highly braided river. In this paper we summarize the evidence thus far available for the Late Pleistocene on the population densities in the Nile Valley, and on the models of Nilotic behaviour. In the discussion we include data on the environmental conditions in Eastern Africa, on the aeolian processes in the Western Desert of Egypt derived from satellite images, 14C and OSL dates, in order to formulate a new model that explains the observed high remnants of aeolian and Nilotic deposits and the related Late Palaeolithic sites. This model hypothesizes that, during the Late Pleistocene, and especially the LGM, dunes from the Western Desert invaded the Nile Valley at several places in Upper Egypt. The much reduced activity of the White Nile and the Blue Nile was unable to evacuate incoming aeolian sand and, as a consequence, several dams were created in the Upper Egyptian Nile Valley. Behind such dams the created lakes offered ideal conditions for human subsistence. This model explains the occurrence of Late Palaeolithic hunter-fisher-gatherers in a very arid environment with very low Nile flows

  11. Thermal preference predicts animal personality in Nile tilapia Oreochromis niloticus.

    Science.gov (United States)

    Cerqueira, Marco; Rey, Sonia; Silva, Tome; Featherstone, Zoe; Crumlish, Margaret; MacKenzie, Simon

    2016-09-01

    Environmental temperature gradients provide habitat structure in which fish orientate and individual thermal choice may reflect an essential integrated response to the environment. The use of subtle thermal gradients likely impacts upon specific physiological and behavioural processes reflected as a suite of traits described by animal personality. In this study, we examine the relationship between thermal choice, animal personality and the impact of infection upon this interaction. We predicted that thermal choice in Nile tilapia Oreochromis niloticus reflects distinct personality traits and that under a challenge individuals exhibit differential thermal distribution. Nile tilapia were screened following two different protocols: 1) a suite of individual behavioural tests to screen for personality and 2) thermal choice in a custom-built tank with a thermal gradient (TCH tank) ranging from 21 to 33 °C. A first set of fish were screened for behaviour and then thermal preference, and a second set were tested in the opposite fashion: thermal then behaviour. The final thermal distribution of the fish after 48 h was assessed reflecting final thermal preferendum. Additionally, fish were then challenged using a bacterial Streptococcus iniae model infection to assess the behavioural fever response of proactive and reactive fish. Results showed that individuals with preference for higher temperatures were also classified as proactive with behavioural tests and reactive contemporaries chose significantly lower water temperatures. All groups exhibited behavioural fever recovering personality-specific thermal preferences after 5 days. Our results show that thermal preference can be used as a proxy to assess personality traits in Nile tilapia and it is a central factor to understand the adaptive meaning of animal personality within a population. Importantly, response to infection by expressing behavioural fever overrides personality-related thermal choice. PMID:27219014

  12. Merowe Dam and the inundation of paleochannels of the Nile

    CERN Document Server

    Sparavigna, Amelia Carolina

    2010-01-01

    The course of the Nile in northern Sudan follows a contorted path through bedrocks, creating the Great Bend. Few years ago, the satellite images showed a fertile strip of land with villages, where paleochannels of the river hosted many fields with cultivations and archaeological sites. Now, a huge part of this valley is under the waters of Merowe Dam reservoir. Comparing the images of the region before and after the dam gates were closed, we can see that the reservoir created itself through flooding the paleochannels.

  13. Hydrological characterization of watersheds in the Blue Nile Basin, Ethiopia

    OpenAIRE

    S. G. Gebrehiwot; Ilstedt, U.; Gärdenas, A. I.; Bishop, K.

    2011-01-01

    Thirty-two watersheds (31–4350 km2), in the Blue Nile Basin, Ethiopia, were hydrologically characterized with data from a study of water and land resources by the US Department of Interior, Bureau of Reclamation (USBR) published in 1964. The USBR document contains data on flow, topography, geology, soil type, and land use for the period 1959 to 1963. The aim of the study was to identify watershed variables best explaining the variation in the hydrological regime, with a...

  14. Human Monoclonal Antibodies as Candidate Therapeutics Against Emerging Viruses and HIV-1

    Institute of Scientific and Technical Information of China (English)

    Zhongyu Zhu; Ponraj Prabakaran; Weizao Chen; Christopher C.Broder; Rui Gong; Dimiter S.Dimitrov

    2013-01-01

    More than 40 monoclonal antibodies (mAbs) have been approved for a number of disease indications with only one of these (Synagis)-for a viral disease,and not for therapy but for prevention.However,in the last decade novel potent mAbs have been discovered and characterized with potential as therapeutics against viruses of major importance for public health and biosecurity including Hendra virus (HeV),Nipah virus (NiV),severe acute respiratory syndrome coronavirus (SARS-CoV),Ebola virus (EBOV),West Nile virus (WNV),influenza virus (IFV) and human immunodeficiency virus type 1 (HIV-1).Here,we review such mAbs with an emphasis on antibodies of human origin,and highlight recent results as well as technologies and mechanisms related to their potential as therapeutics.

  15. Natural equilibria and anthropic effects on sediment transport in big river systems: The Nile case

    Science.gov (United States)

    Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Vezzoli, Giovanni; Villa, Igor

    2014-05-01

    The Nile River flows for ~ 6700 km, from Burundi and Rwanda highlands south of the Equator to the Mediterranean Sea at northern subtropical latitudes. It is thus the longest natural laboratory on Earth, a unique setting in which we are carrying out a continuing research project to investigate changes in sediment composition associated with a variety of chemical and physical processes, including weathering in equatorial climate and hydraulic sorting during transport and deposition. Petrographic, mineralogical, chemical, and isotopic fingerprints of sand and mud have been monitored along all Nile branches, from the Kagera and White Nile draining Archean, Paleoproterozoic and Mesoproterozoic basements uplifted along the western branch of the East African rift, to the Blue Nile and Atbara Rivers sourced in Ethiopian volcanic highlands made of Oligocene basalt. Downstream of the Atbara confluence, the Nile receives no significant tributary water and hardly any rainfall across the Sahara. After construction of the Aswan High Dam in 1964, the Nile ceased to be an active conveyor-belt in Egypt, where the mighty river has been tamed to a water canal; transported sediments are thus chiefly reworked from older bed and levee deposits, with minor contributions from widyan sourced in the Red Sea Hills and wind-blown desert sand and dust. Extensive dam construction has determined a dramatic sediment deficit at the mouth, where deltaic cusps are undergoing ravaging erosion. Nile delta sediments are thus recycled under the effect of dominant waves from the northwest, the longest Mediterranean fetch direction. Nile sands, progressively enriched in more stable minerals such as quartz and amphiboles relative to volcanic rock fragments and pyroxene, thus undergo multistep transport by E- and NE-directed longshore currents all along the coast of Egypt and Palestine, and are carried as far as Akko Bay in northern Israel. Nile mud reaches the Iskenderun Gulf in southern Turkey. A full

  16. Intraspecific variation in gill morphology of juvenile Nile perch, Lates niloticus, in Lake Nabugabo, Uganda

    Science.gov (United States)

    Paterson, Jaclyn A.; Chapman, Lauren J.; Schofield, Pamela J.

    2010-01-01

    Several studies have demonstrated intraspecific variation in fish gill size that relates to variation in dissolved oxygen (DO) availability across habitats. In Lake Nabugabo, East Africa, ecological change over the past 12 years has coincided with a shift in the distribution of introduced Nile perch such that a larger proportion of the population now inhabits waters in or near wetland ecotones where DO is lower than in open waters of the lake. In this study, we compared gill size of juvenile Nile perch between wetland and exposed (open-water) habitats of Lake Nabugabo in 2007, as well as between Nile perch collected in 1996 and 2007. For Nile perch of Lake Nabugabo [<20 cm total length (TL)], there was a significant habitat effect on some gill traits. In general, fish from wetland habitats were characterized by a longer total gill filament length and average gill filament length than conspecifics from exposed habitats. Nile perch collected from wetland areas in 2007 had significantly larger gills (total gill filament length) than Nile perch collected in 1996, but there was no difference detected between Nile perch collected from exposed sites in 2007 and conspecifics collected in 1996.

  17. Was Lates Late? A Null Model for the Nile Perch Boom in Lake Victoria

    Science.gov (United States)

    Downing, Andrea S.; Galic, Nika; Goudswaard, Kees P. C.; van Nes, Egbert H.; Scheffer, Marten; Witte, Frans; Mooij, Wolf M.

    2013-01-01

    Nile perch (Lates niloticus) suddenly invaded Lake Victoria between 1979 and 1987, 25 years after its introduction in the Ugandan side of the lake. Nile perch then replaced the native fish diversity and irreversibly altered the ecosystem and its role to lakeshore societies: it is now a prised export product that supports millions of livelihoods. The delay in the Nile perch boom led to a hunt for triggers of the sudden boom and generated several hypotheses regarding its growth at low abundances – all hypotheses having important implications for the management of Nile perch stocks. We use logistic growth as a parsimonious null model to predict when the Nile perch invasion should have been expected, given its growth rate, initial stock size and introduction year. We find the first exponential growth phase can explain the timing of the perch boom at the scale of Lake Victoria, suggesting that complex mechanisms are not necessary to explain the Nile perch invasion or its timing. However, the boom started in Kenya before Uganda, indicating perhaps that Allee effects act at smaller scales than that of the whole Lake. The Nile perch invasion of other lakes indicates that habitat differences may also have an effect on invasion success. Our results suggest there is probably no single management strategy applicable to the whole lake that would lead to both efficient and sustainable exploitation of its resources. PMID:24204684

  18. Nile Red Staining for Oil Determination in Microalgal Cells: A New Insight through Statistical Modelling

    Directory of Open Access Journals (Sweden)

    Ronald Halim

    2015-01-01

    Full Text Available In the wake of global warming and rapid fossil fuel depletion, microalgae emerge as promising feedstocks for sustainable biofuel production. Nile red staining acts as a rapid diagnostic tool to measure the amount of biodiesel-convertible lipid that the cells accumulate. There is a need for the development of a more uniform staining procedure. In its first phase, this study examined the dependence of microalgal Nile red fluorescence (Tetraselmis suecica in terms of its most pertinent staining variables. A quadratic surface model that successfully described the Nile red fluorescence intensity as a composite function of its variables was generated (r2=0.86. Cell concentration was shown to have a significant effect on the fluorescence intensity. Up to a certain threshold, fluorescence intensity was shown to increase with Nile red dye concentration. In its second phase, the study reviewed findings from previous Nile red studies to elucidate some of the fundamental mechanism underlying the diffusion of Nile red dye molecules into the microalgal cells and their subsequent interaction with intracellular lipids. Through the review process, we were able to develop a simple framework that provided a set of guidelines for the standardization of the Nile red staining procedure across different microalgal species.

  19. The Landscape and Archaeology of Jebel Sabaloka and the Sixth Nile Cataract, Sudan

    Directory of Open Access Journals (Sweden)

    Lenka Suková

    2012-12-01

    Full Text Available There are only six cataracts on the Main Nile of which the sixth Nile cataract located ca. 80 km downstream of the confluence of the Blue and White Niles represents the southernmost and smallest of theseries. Despite its close vicinity to Khartoum, this area was the least studied cataract zone along the Middle Nile until 2009 when it became the object of geoarchaeological research by the Czech Institute of Egyptology (Faculty of Arts, Charles University in Prague and the Institute of Geology (Academy of Sciences of the Czech Republic. Four field campaigns have been carried out in Jebel Sabaloka and the Sixth Nile Cataract up to now, of which the first two were focused on landscape archaeology of a “large scale”, i.e. on the recognition of all observable human influencesin the research area of approx. 15×20 km. The main result of the first landscape archaeological reconnaissance consistsin the localisation and first description of ca. 30 major sites spanning from the Middle Palaeolithic up to the recent past. A peculiar archaeological feature of this part of the nile Valley has turned out to be the existence of a dense network of terraced “villages” connected via old paths with the Nile and with the periphery of the mountains. Furthermore, two Christian and Islamic forts have been found at places guarding the crossing of the Nile above the sixth cataract. Last but not least, a large number of prehistoric sites, including an extraordinarily rich settlement dated to the Mesolithic and Neolithic periods, has been described as well. After the first two seasons, the findings of which are summarised in this paper, it can be argued that the last of the six Nile cataracts to be investigated has finally begun to reveal its rich and hitherto unknown archaeological past.

  20. Hydroclimate variability in the Nile River Basin during the past 28,000 years

    Science.gov (United States)

    Castañeda, Isla S.; Schouten, Stefan; Pätzold, Jürgen; Lucassen, Friedrich; Kasemann, Simone; Kuhlmann, Holger; Schefuß, Enno

    2016-03-01

    It has long been known that extreme changes in North African hydroclimate occurred during the late Pleistocene yet many discrepancies exist between sites regarding the timing, duration and abruptness of events such as Heinrich Stadial (HS) 1 and the African Humid Period (AHP). The hydroclimate history of the Nile River is of particular interest due to its lengthy human occupation history yet there are presently few continuous archives from the Nile River corridor, and pre-Holocene studies are rare. Here we present new organic and inorganic geochemical records of Nile Basin hydroclimate from an eastern Mediterranean (EM) Sea sediment core spanning the past 28 ka BP. Our multi-proxy records reflect the fluctuating inputs of Blue Nile versus White Nile material to the EM Sea in response to gradual changes in local insolation and also capture abrupt hydroclimate events driven by remote climate forcings, such as HS1. We find strong evidence for extreme aridity within the Nile Basin evolving in two distinct phases during HS1, from 17.5 to 16 ka BP and from 16 to 14.5 ka BP, whereas peak wet conditions during the AHP are observed from 9 to 7 ka BP. We find that zonal movements of the Congo Air Boundary (CAB), and associated shifts in the dominant moisture source (Atlantic versus Indian Ocean moisture) to the Nile Basin, likely contributed to abrupt hydroclimate variability in northern East Africa during HS1 and the AHP as well as to non-linear behavior of hydroclimate proxies. We note that different proxies show variable gradual and abrupt responses to individual hydroclimate events, and thus might have different inherent sensitivities, which may be a factor contributing to the controversy surrounding the abruptness of past events such as the AHP. During the Late Pleistocene the Nile Basin experienced extreme hydroclimate fluctuations, which presumably impacted Paleolithic cultures residing along the Nile corridor.

  1. Masculinization of Nile tilapia (Oreochromis niloticus) by immersion in androgens

    Science.gov (United States)

    Gale, W.L.; Fitzpatrick, M.S.; Lucero, M.; Contreras-Sanchez, W.M.; Schreck, C. B.

    1999-01-01

    The use of all-male populations increases the efficiency and feasibility of tilapia aquaculture. The objective of this study was to determine the efficacy of a short-term immersion procedure for masculinizing Nile tilapia (Oreochromis niloticus). Two synthetic androgens were evaluated: 17α-methyldihydrotestosterone (MDHT) and 17α-methyltestosterone (MT). Exposure (3 h) on 10 and again on 13 days post-fertilization to MDHT at 500 μg/1 successfully masculinized fry in all experiments, resulting in 100, 94 and 83 ± 2% males in Experiments 1, 2 and 3, respectively. Immersions in MDHT or MT at 100 μg/1 resulted in significantly skewed sex ratios in Experiments 1 and 3 (MT resulted in 73 and 83 ± 3% males; and MDHT resulted in 72 and 91 ± 1% males) but not in Experiment 2. Immersion in MT at 500 μg/1 only caused masculinization in Experiment 3. Although further research and refinement is needed, immersion of Nile tilapia in MDHT may provide a practical alternative to the use of steroid-treated feed. Furthermore, when compared with current techniques for steroid-induced sex inversion of tilapia, short-term immersion reduces the period of time that workers are exposed to anabolic steroids.

  2. Efficiency of aquatic macrophytes to treat Nile tilapia pond effluents

    Directory of Open Access Journals (Sweden)

    Henry-Silva Gustavo Gonzaga

    2006-01-01

    Full Text Available The effluents from fish farming can increase the quantity of suspended solids and promote the enrichment of nitrogen and phosphorus in aquatic ecosystems. In this context, the aim of this work was to evaluate the efficiency of three species of floating aquatic macrophytes (Eichhornia crassipes, Pistia stratiotes and Salvinia molesta to treat effluents from Nile tilapia culture ponds. The effluent originated from a 1,000-m² pond stocked with 2,000 male Nile tilapia Oreochromis niloticus. The treatment systems consisted of 12 experimental tanks, three tanks for each macrophyte species, and three control tanks (without plants. Water samples were collected from the: (i fish pond source water, (ii effluent from fish pond and (iii effluents from the treatment tanks. The following water variables were evaluated: turbidity, total and dissolved nitrogen, ammoniacal-N, nitrate-N, nitrite-N, total phosphorus and dissolved phosphorus. E. crassipes and P. stratiotes were more efficient in total phosphorus removal (82.0% and 83.3%, respectively and total nitrogen removal (46.1% and 43.9%, respectively than the S. molesta (72.1% total phosphorus and 42.7% total nitrogen and the control (50.3% total phosphorus and 22.8% total nitrogen, indicating that the treated effluents may be reused in the aquaculture activity.

  3. The Impact of Wolbachia on Virus Infection in Mosquitoes

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    Karyn N. Johnson

    2015-11-01

    Full Text Available Mosquito-borne viruses such as dengue, West Nile and chikungunya viruses cause significant morbidity and mortality in human populations. Since current methods are not sufficient to control disease occurrence, novel methods to control transmission of arboviruses would be beneficial. Recent studies have shown that virus infection and transmission in insects can be impeded by co-infection with the bacterium Wolbachia pipientis. Wolbachia is a maternally inherited endosymbiont that is commonly found in insects, including a number of mosquito vector species. In Drosophila, Wolbachia mediates antiviral protection against a broad range of RNA viruses. This discovery pointed to a potential strategy to interfere with mosquito transmission of arboviruses by artificially infecting mosquitoes with Wolbachia. This review outlines research on the prevalence of Wolbachia in mosquito vector species and the impact of antiviral effects in both naturally and artificially Wolbachia-infected mosquitoes.

  4. Environmental management of mosquito-borne viruses in Rhode Island

    Science.gov (United States)

    Ginsberg, Howard S.; Gettman, Alan; Becker, Elisabeth; Bandyopadhyay, Ananda S.; LeBrun, Roger A.

    2013-01-01

    West Nile Virus (WNV) and Eastern Equine Encephalitis Virus (EEEV) are both primarily bird viruses, which can be transmitted by several mosquito species. Differences in larval habitats, flight, and biting patterns of the primary vector species result in substantial differences in epidemiology, with WNV more common, primarily occurring in urban areas, and EEEV relatively rare, typically occurring near swamp habitats. The complex transmission ecology of these viruses complicates prediction of disease outbreaks. The Rhode Island Department of Environmental Management (DEM) and Department of Health (DoH) provide prevention assistance to towns and maintain a mosquito surveillance program to identify potential disease risk. Responses to potential outbreaks follow a protocol based on surveillance results, assessment of human risk, and technical consultation.

  5. Pesticide residues in Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) from Southern Lake Victoria, Tanzania

    Energy Technology Data Exchange (ETDEWEB)

    Henry, L. [Chemistry Department, University of Dar es Salaam. PO Box 35061, Dar es Salaam (Tanzania); Kishimba, M.A. [Chemistry Department, University of Dar es Salaam. PO Box 35061, Dar es Salaam (Tanzania)]. E-mail: kishimba@chem.udsm.ac.tz

    2006-03-15

    Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) samples were collected from fish landing stations in nine riparian districts on the Tanzanian side of Lake Victoria and screened for residues of 64 organochlorine, organophosphorus, carbamate, and pyrethroid pesticides. The residue levels in the fish fillet were up to 0.003, 0.03 and 0.2 mg/kg fresh weight (0.7, 3.8 and 42 mg/kg lipid weight) of fenitrothion, DDT and endosulfan, respectively. Mean levels within sites were up to 0.002, 0.02 and 0.1 mg/kg fresh weight (0.5, 0.5 and 16 mg/kg lipid weight), respectively. The detection of higher levels of p,p'-DDT than the degradation products (p,p'-DDD and p,p'-DDE), and higher levels of endosulfan isomers ({alpha} and {beta}) than the sulphate, in fish samples, implied recent exposure of fish to DDT and endosulfan, respectively. Generally, most of the fish samples had residue levels above the average method detection limits (MDLs), but were within the calculated ADI. - Fish from Lake Victoria had relatively low pesticide levels.

  6. Normal haematology and blood biochemistry of wild Nile crocodiles (Crocodylus niloticus in the Okavango Delta, Botswana

    Directory of Open Access Journals (Sweden)

    C.J. Lovely

    2007-06-01

    Full Text Available Wild Nile crocodiles (Crocodylus niloticus of various size classes were captured in the Okavango Delta, Botswana. Blood was collected from the post occipital sinus and used for the determination of a wide range of haematological and biochemical parameters. These values were compared between the sexes and between 3 size classes. The values were also compared with the limited data available from farmed Nile crocodiles, as well as from other wild Nile crocodiles. The Okavango crocodiles were comparatively anaemic, and had comparatively low total protein and blood glucose levels. There was a high prevalence of Hepatozoon pettiti infection, however, there was no significant difference in haematological values between the infected and uninfected crocodiles. The values reported here will be useful in diagnostic investigations in both zoo and farmed Nile crocodiles.

  7. Zika Virus: the Latest Newcomer.

    Science.gov (United States)

    Saiz, Juan-Carlos; Vázquez-Calvo, Ángela; Blázquez, Ana B; Merino-Ramos, Teresa; Escribano-Romero, Estela; Martín-Acebes, Miguel A

    2016-01-01

    Since the beginning of this century, humanity has been facing a new emerging, or re-emerging, virus threat almost every year: West Nile, Influenza A, avian flu, dengue, Chikungunya, SARS, MERS, Ebola, and now Zika, the latest newcomer. Zika virus (ZIKV), a flavivirus transmitted by Aedes mosquitoes, was identified in 1947 in a sentinel monkey in Uganda, and later on in humans in Nigeria. The virus was mainly confined to the African continent until it was detected in south-east Asia the 1980's, then in the Micronesia in 2007 and, more recently in the Americas in 2014, where it has displayed an explosive spread, as advised by the World Health Organization, which resulted in the infection of hundreds of thousands of people. ZIKV infection was characterized by causing a mild disease presented with fever, headache, rash, arthralgia, and conjunctivitis, with exceptional reports of an association with Guillain-Barre syndrome (GBS) and microcephaly. However, since the end of 2015, an increase in the number of GBS associated cases and an astonishing number of microcephaly in fetus and new-borns in Brazil have been related to ZIKV infection, raising serious worldwide public health concerns. Clarifying such worrisome relationships is, thus, a current unavoidable goal. Here, we extensively review what is currently known about ZIKV, from molecular biology, transmission routes, ecology, and epidemiology, to clinical manifestations, pathogenesis, diagnosis, prophylaxis, and public health. PMID:27148186

  8. Zika virus: the latest newcomer

    Directory of Open Access Journals (Sweden)

    Juan-Carlos eSaiz

    2016-04-01

    Full Text Available Since the beginning of this century, humanity has been facing a new emerging, or re-emerging, virus threat almost every year: West Nile, Influenza A, avian flu, dengue, Chikungunya, SARS, MERS, Ebola, and now Zika, the latest newcomer. Zika virus (ZIKV, a flavivirus transmitted by Aedes mosquitoes, was identified in 1947 in a sentinel monkey in Uganda, and later on in humans in Nigeria. The virus was mainly confined to the African continent until it was detected in south-east Asia the 1980´s, then in the Micronesia in 2007 and, more recently in the Americas in 2014, where it has displayed an explosive spread, as advised by the World Health Organization (WHO, which resulted in the infection of hundreds of thousands of people. ZIKV infection was characterized by causing a mild disease presented with fever, headache, rash, arthralgia, and conjunctivitis, with exceptional reports of an association with Guillain-Barre syndrome (GBS and microcephaly. However, since the end of 2015, an increase in the number of GBS associated cases and an astonishing number of microcephaly in foetus and new-borns in Brazil have been related to ZIKV infection, raising serious worldwide public health concerns. Clarifying such worrisome relationships is, thus, a current unavoidable goal. Here, we extensively review what is currently known about ZIKV, from molecular biology, transmission routes, ecology and epidemiology, to clinical manifestations, pathogenesis, diagnosis, prophylaxis and public health.

  9. Zika Virus: the Latest Newcomer

    Science.gov (United States)

    Saiz, Juan-Carlos; Vázquez-Calvo, Ángela; Blázquez, Ana B.; Merino-Ramos, Teresa; Escribano-Romero, Estela; Martín-Acebes, Miguel A.

    2016-01-01

    Since the beginning of this century, humanity has been facing a new emerging, or re-emerging, virus threat almost every year: West Nile, Influenza A, avian flu, dengue, Chikungunya, SARS, MERS, Ebola, and now Zika, the latest newcomer. Zika virus (ZIKV), a flavivirus transmitted by Aedes mosquitoes, was identified in 1947 in a sentinel monkey in Uganda, and later on in humans in Nigeria. The virus was mainly confined to the African continent until it was detected in south-east Asia the 1980’s, then in the Micronesia in 2007 and, more recently in the Americas in 2014, where it has displayed an explosive spread, as advised by the World Health Organization, which resulted in the infection of hundreds of thousands of people. ZIKV infection was characterized by causing a mild disease presented with fever, headache, rash, arthralgia, and conjunctivitis, with exceptional reports of an association with Guillain–Barre syndrome (GBS) and microcephaly. However, since the end of 2015, an increase in the number of GBS associated cases and an astonishing number of microcephaly in fetus and new-borns in Brazil have been related to ZIKV infection, raising serious worldwide public health concerns. Clarifying such worrisome relationships is, thus, a current unavoidable goal. Here, we extensively review what is currently known about ZIKV, from molecular biology, transmission routes, ecology, and epidemiology, to clinical manifestations, pathogenesis, diagnosis, prophylaxis, and public health. PMID:27148186

  10. The Medicinal Chemistry of Dengue Virus.

    Science.gov (United States)

    Behnam, Mira A M; Nitsche, Christoph; Boldescu, Veaceslav; Klein, Christian D

    2016-06-23

    The dengue virus and related flaviviruses are an increasing global health threat. In this perspective, we comment on and review medicinal chemistry efforts aimed at the prevention or treatment of dengue infections. We include target-based approaches aimed at viral or host factors and results from phenotypic screenings in cellular assay systems for viral replication. This perspective is limited to the discussion of results that provide explicit chemistry or structure-activity relationship (SAR), or appear to be of particular interest to the medicinal chemist for other reasons. The discovery and development efforts discussed here may at least partially be extrapolated toward other emerging flaviviral infections, such as West Nile virus. Therefore, this perspective, although not aimed at flaviviruses in general, should also be able to provide an overview of the medicinal chemistry of these closely related infectious agents. PMID:26771861

  11. Emergence and Spreading Potential of Zika Virus

    Science.gov (United States)

    Fajardo, Álvaro; Cristina, Juan; Moreno, Pilar

    2016-01-01

    Zika virus (ZIKV) is an arthropod-borne Flavivirus (family Flaviviridae) closely related to dengue, yellow fever and West Nile viruses. ZIKV remained neglected, confined to enzootic transmission cycles in Africa and Asia, until the first significant outbreak was reported in Micronesia in 2007. Subsequent epidemics of growing incidence occurred in French Polynesia and other South Pacific Islands, and recently, in the Americas. The latter and currently ongoing outbreak of unprecedented incidence revealed the association of ZIKV infection with the occurrence of severe congenital malformations and neurological diseases, leading to a widespread concern about its potential to pose a global public health threat. Serological and molecular data suggest that the genetic and geographic diversification of ZIKV may be greatly underestimated. Here we discuss several ecological and epidemiological aspects, together with the evolutionary processes that may have driven the emergence and abrupt spread of ZIKV in the Americas. PMID:27812357

  12. Selectivity of three aquatic weeds as diet for Nile tilapia (Oreochromis niloticus)

    OpenAIRE

    Agbede, S.A.; Akinyemi, O.; A. E. Falaye; Atsanda, N. N.; Adeyemo, A.O.; Adesina, A. A.

    2001-01-01

    A total of sixty juvenile Oreochromis niloticus (Nile tilapia) were fed three species of aquatic weed, namely Azolla filiculoides (water fern), Elodea sp. and Pistia stratiotes (water lettuce) to determine which of the weeds will be selectively consumed, and preferred of all. A control group of twenty Nile tilapia was fed compounded feed. The selectivity of the weeds was observed based on their utilization as food source, and Azolla filiculoides was found to be highly utilized, followed by El...

  13. Understanding Catchment Processes and Hydrological Modelling in the Abay/Upper Blue Nile Basin, Ethiopia

    OpenAIRE

    Gebrekristos, S.T.

    2015-01-01

    The water resources in the Abay/Upper Blue Nile basin are the source of life for the several hundred million people living in the basin and further downstream. It provides more than 60% of the total Nile water. Intensive farming in unfavourable soils and slopes, overgrazing and soil erosion is among the major problems in the basin. Land degradation as a result of soil erosion decreases soil fertility in the upper catchments and simultaneously increases sedimentation in reservoirs and irrigati...

  14. The biology, ecology, population parameters and the fishery of the Nile tilapia, Oreochromis niloticus (L)

    OpenAIRE

    Balirwa, J.S.

    1994-01-01

    Oreochromis niloticus (the Nile tilapia) and three other ti1apine species: Oreochromis leucostictus, Tilapia zi11ii and T. rendallii were introduced into Lakes Victoria, Kyoga and Nabugabo in 1950s and 1960s. The source and foci of the stockings are given by Welcomme (1966) but the origin of the stocked species was Lake Albert. The Nile tilapia was introduced as a management measure to relieve fishing pressure on the endemic tiapiines and, since it grows to a bigger size, to...

  15. Impacts of global change on the Nile basin: Options for hydropolitical reform in Egypt and Ethiopia

    OpenAIRE

    Martens, Anja Kristina

    2011-01-01

    This paper analyzes drivers of global change and their impacts on the current and future availability and accessibility of water resources in the Nile Basin. Drivers include changes in demography, climate, the socioeconomy, and politics, all of which are likely to increase the demand for freshwater and thus competition over its use across riparian countries. As a result of historic bilateral agreements, Egypt, as the most downstream country, uses the lion's share of the Nile's waters, which m...

  16. MORPHOLOGICAL AND RADIOLOGICAL STUDIES ON THE SKULL OF THE NILE CROCODILE (CROCODYLUS NILOTICUS)

    OpenAIRE

    Nora A. Shaker; Samah H. El-Bably

    2015-01-01

    Background and Aim: Present study provides with more anatomical information on the structure and form of the bones forming the cranium of the Nile crocodile helps in understanding the interpretation of X ray images and surgical affection of the crocodile heads. Materials and Methods: The present study was conducted on six heads of the Nile crocodile (Crocodylus niloticus). The heads were removed from their bodies and prepared by hot water maceration technique. The bones of the skull were s...

  17. Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus)

    OpenAIRE

    Dirk G. Booyse; Fritz W. Huchzermeyer; Soley, John T; Herman B. Groenewald; Lizette C. Bekker; Jan G. Myburgh; Taisen Iguchi; Louis J. Guillette, Jr

    2012-01-01

    Urine samples can be a very useful diagnostic tool for the evaluation of animal health. In this article, a simple technique to collect urine from the Nile crocodile (Crocodylus niloticus) was described, based on a similar unpublished technique developed for the American alligator (Alligator mississippiensis) using a canine urinary catheter. With this technique, it was possible to collect relatively clean urine samples from Nile crocodiles of different sizes using canine urinary catheters or s...

  18. ECHO virus

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001340.htm ECHO virus To use the sharing features on this page, please enable JavaScript. Enteric cytopathic human orphan (ECHO) viruses are a group of viruses that lead to ...

  19. Seroepizootiological-epidemiological investigation and mapping of West Nile infection in the Republic of Serbia

    Directory of Open Access Journals (Sweden)

    Đuričić Bosiljka

    2013-01-01

    Full Text Available The disease caused by the West Nile virus (WNV has been known since 1937 when it was described for the first time in Uganda. After spreading to Europe and the Middle East, the disease has changed its primary location. Today WN infection is a significant health problem in the world. As a result of the current epizootiological and epidemiological situation in Europe studies on the occurrence of WND were introduced in Serbia, also. The investigation on the presence of WNV antibodies was intensified in the period from 2008 to 2012. In this period a total of 3618 serum samples were tested from 18 localities (2736 animal sera from 8 different species and 882 human sera samples. The method applied was gel immunodiffusion and the representative samples were confirmed by the plaque reduction test (PRNT-90. Out of the total number of samples WNV antibodies were present in 3.97% horses, 0.93% dogs, 0.31% poultry and 1.36% man. In one horse serum sample there was a positive reaction with a positive control serum, thus indicating the presence of WNV antigen. The results have confirmed that WNV antibodies are present in 9 out of 18 tested locations in the Republic of Serbia. The percentage of seropositive samples varies from 0.42% in Pozarevac (horses and humans up to 6.45% in Novi Pazar (dogs. Out of the investigated species the highest seropositivity was recorded in horses (3.97%, and lowest in poultry (0.31%. WNV is present and widespread in the Republic of Serbia, thus enabling distribution mapping. [Projekat Ministarstva nauke Republike Srbije, br. TR 21047 i br. TR 37015

  20. Mapping the serological prevalence rate of West Nile fever in equids, Tunisia.

    Science.gov (United States)

    Bargaoui, R; Lecollinet, S; Lancelot, R

    2015-02-01

    West Nile fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in equid sera. However, clinical cases were never reported in equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis. PMID:23906318

  1. Prospective Study of Pregnancy and Newborn Outcomes in Mothers with West Nile Illness during Pregnancy

    Science.gov (United States)

    Pridjian, Gabriella; Sirois, Patricia A.; McRae, Scott; Hinckley, Alison F.; Rasmussen, Sonja A.; Kissinger, Patricia; Buekens, Pierre; Hayes, Edward B.; O’Leary, Dan; Kuhn, Stephanie; Swan, Kenneth F.; Xiong, Xu; Wesson, Dawn M.

    2016-01-01

    Background A previous case report of West Nile virus (WNV) illness during pregnancy suggested that WNV could be a cause of congenital defects. We performed a prospective, longitudinal cohort study of pregnant women with WNV illness to increase our knowledge of the effects of WNV illness during pregnancy. Methods Participants were enrolled in 2005 to 2008 from pregnant women with serologically confirmed WNV illness reported to the Centers for Disease Control and Prevention. Comparison was made to WNV-uninfected women, matched on maternal age and enrollment month. Pregnancy and newborn data were collected; cord blood WNV serology was obtained. Pediatric exams and the Bayley Scales of Infant and Toddler Development-Third Edition (Bayley-III) were performed. Results Twenty-eight WNV-infected mothers and 25 WNV-uninfected mothers participated. Maternal demographics were similar except for a higher rate of planned pregnancies, education, and household income in the WNV-uninfected mothers. There were no differences in pregnancy and delivery characteristics except that infected mothers had a higher incidence of febrile illnesses and used more medications. Birth weight, length, head circumference, and rate of congenital malformations were similar in babies born to WNV-infected and -uninfected mothers. Follow-up physical exams were generally normal. The Bayley-III assessments, available for 17 children born to mothers with WNV illness, showed performance at or above age level across domains. Conclusion The risk for adverse pregnancy and newborn outcomes in women experiencing WNV illness in pregnancy appears to be low, but future studies with larger numbers are needed to rule out a small risk. PMID:27223334

  2. Development of a human live attenuated West Nile infectious DNA vaccine: Suitability of attenuating mutations found in SA14-14-2 for WN vaccine design.

    Science.gov (United States)

    Yamshchikov, Vladimir; Manuvakhova, Marina; Rodriguez, Efrain

    2016-01-01

    Direct attenuation of West Nile (WN) virus strain NY99 for the purpose of vaccine development is not feasible due to its high virulence and pathogenicity. Instead, we created highly attenuated chimeric virus W1806 with the serological identity of NY99. To further attenuate W1806, we investigated effects of mutations found in Japanese encephalitis virus vaccine SA14-14-2. WN viruses carrying all attenuating mutations lost infectivity in mammalian, but not in mosquito cells. No single reversion restored infectivity in mammalian cells, although increased infectivity in mosquito cells was observed. To identify a subset of mutations suitable for further attenuation of W1806, we analyzed effects of E138K and K279M changes on virulence, growth properties, and immunogenicity of derivatized W956, from which chimeric W1806 inherited its biological properties and attenuation profile. Despite strong dominant attenuating effect, introduction of only two mutations was not sufficient for attenuating W1806 to the safety level acceptable for human use.

  3. Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label

    Directory of Open Access Journals (Sweden)

    Nattawut Yotapan

    2014-09-01

    Full Text Available DNA or its analogues with an environment-sensitive fluorescent label are potentially useful as a probe for studying the structure and dynamics of nucleic acids. In this work, pyrrolidinyl peptide nucleic acid (acpcPNA was labeled at its backbone with Nile red, a solvatochromic benzophenoxazine dye, by means of click chemistry. The optical properties of the Nile red-labeled acpcPNA were investigated by UV–vis and fluorescence spectroscopy in the absence and in the presence of DNA. In contrast to the usual quenching observed in Nile red-labeled DNA, the hybridization with DNA resulted in blue shifting and an enhanced fluorescence regardless of the neighboring bases. More pronounced blue shifts and fluorescence enhancements were observed when the DNA target carried a base insertion in close proximity to the Nile red label. The results indicate that the Nile red label is located in a more hydrophobic environment in acpcPNA–DNA duplexes than in the single-stranded acpcPNA. The different fluorescence properties of the acpcPNA hybrids of complementary DNA and DNA carrying a base insertion are suggestive of different interactions between the Nile red label and the duplexes.

  4. Species diversity defends against the invasion of Nile tilapia (Oreochromis niloticus

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    Gu Dang E.

    2014-05-01

    Full Text Available Nile tilapia (Oreochromis niloticus is one of the most widely cultured species globally and has successfully colonized much of the world. Despite numerous studies of this exotic species, how differences in native communities mitigate the consequences of Nile tilapia invasion is unknown. Theory predicts that communities that are more diverse should be more resistant to exotic species, an effect that is referred to as “biotic resistance”, but these effects are spatially dependent and organism-specific. Field surveys and laboratory experiments were conducted to test the theory of “biotic resistance” and ascertain the relationship between native species richness and the invasion of Nile tilapia. In the field, we found that as native species richness increased, the biomass of Nile tilapia was significantly reduced. Consistent with results from the field, our manipulative experiment indicated that the growth of Nile tilapia was negatively related to native species richness. Thus, our study supports the theory of “biotic resistance” and suggests that species biodiversity represents an important defense against the invasion of Nile tilapia.

  5. Mutually beneficial and sustainable management of Ethiopian and Egyptian dams in the Nile Basin

    Science.gov (United States)

    Habteyes, Befekadu G.; Hasseen El-bardisy, Harb A. E.; Amer, Saud A.; Schneider, Verne R.; Ward, Frank A.

    2015-10-01

    Ongoing pressures from population growth, recurrent drought, climate, urbanization and industrialization in the Nile Basin raise the importance of finding viable measures to adapt to these stresses. Four tributaries of the Eastern Nile Basin contribute to supplies: the Blue Nile (56%), White Nile-Albert (14%), Atbara (15%) and Sobat (15%). Despite much peer reviewed work addressing conflicts on the Nile, none to date has quantitatively examined opportunities for discovering benefit sharing measures that could protect negative impacts on downstream water users resulting from new upstream water storage developments. The contribution of this paper is to examine the potential for mutually beneficial and sustainable benefit sharing measures from the development and operation of the Grand Ethiopian Renaissance Dam while protecting baseline flows to the downstream countries including flows into the Egyptian High Aswan Dam. An integrated approach is formulated to bring the hydrology, economics and institutions of the region into a unified framework for policy analysis. A dynamic optimization model is developed and applied to identify the opportunities for Pareto Improving measures to operate these two dams for the four Eastern Nile Basin countries: Ethiopia, South Sudan, Sudan, and Egypt. Results indicate a possibility for one country to be better off (Ethiopia) and no country to be worse off from a managed operation of these two storage facilities. Still, despite the optimism of our results, considerable diplomatic negotiation among the four riparians will be required to turn potential gains into actual welfare improvements.

  6. Interim Guidance for Interpretation of Zika Virus Antibody Test Results.

    Science.gov (United States)

    Rabe, Ingrid B; Staples, J Erin; Villanueva, Julie; Hummel, Kimberly B; Johnson, Jeffrey A; Rose, Laura; Hills, Susan; Wasley, Annemarie; Fischer, Marc; Powers, Ann M

    2016-01-01

    Zika virus is a single-stranded RNA virus in the genus Flavivirus and is closely related to dengue, West Nile, Japanese encephalitis, and yellow fever viruses (1,2). Among flaviviruses, Zika and dengue virus share similar symptoms of infection, transmission cycles, and geographic distribution. Diagnostic testing for Zika virus infection can be accomplished using both molecular and serologic methods. For persons with suspected Zika virus disease, a positive real-time reverse transcription-polymerase chain reaction (rRT-PCR) result confirms Zika virus infection, but a negative rRT-PCR result does not exclude infection (3-7). In these cases, immunoglobulin (Ig) M and neutralizing antibody testing can identify additional recent Zika virus infections (6,7). However, Zika virus antibody test results can be difficult to interpret because of cross-reactivity with other flaviviruses, which can preclude identification of the specific infecting virus, especially when the person previously was infected with or vaccinated against a related flavivirus (8). This is important because the results of Zika and dengue virus testing will guide clinical management. Pregnant women with laboratory evidence of Zika virus infection should be evaluated and managed for possible adverse pregnancy outcomes and be reported to the U.S. Zika Pregnancy Registry or the Puerto Rico Zika Active Pregnancy Surveillance System for clinical follow-up (9,10). All patients with clinically suspected dengue should have proper management to reduce the risk for hemorrhage and shock (11). If serologic testing indicates recent flavivirus infection that could be caused by either Zika or dengue virus, patients should be clinically managed for both infections because they might have been infected with either virus. PMID:27254248

  7. Interim Guidance for Interpretation of Zika Virus Antibody Test Results.

    Science.gov (United States)

    Rabe, Ingrid B; Staples, J Erin; Villanueva, Julie; Hummel, Kimberly B; Johnson, Jeffrey A; Rose, Laura; Hills, Susan; Wasley, Annemarie; Fischer, Marc; Powers, Ann M

    2016-01-01

    Zika virus is a single-stranded RNA virus in the genus Flavivirus and is closely related to dengue, West Nile, Japanese encephalitis, and yellow fever viruses (1,2). Among flaviviruses, Zika and dengue virus share similar symptoms of infection, transmission cycles, and geographic distribution. Diagnostic testing for Zika virus infection can be accomplished using both molecular and serologic methods. For persons with suspected Zika virus disease, a positive real-time reverse transcription-polymerase chain reaction (rRT-PCR) result confirms Zika virus infection, but a negative rRT-PCR result does not exclude infection (3-7). In these cases, immunoglobulin (Ig) M and neutralizing antibody testing can identify additional recent Zika virus infections (6,7). However, Zika virus antibody test results can be difficult to interpret because of cross-reactivity with other flaviviruses, which can preclude identification of the specific infecting virus, especially when the person previously was infected with or vaccinated against a related flavivirus (8). This is important because the results of Zika and dengue virus testing will guide clinical management. Pregnant women with laboratory evidence of Zika virus infection should be evaluated and managed for possible adverse pregnancy outcomes and be reported to the U.S. Zika Pregnancy Registry or the Puerto Rico Zika Active Pregnancy Surveillance System for clinical follow-up (9,10). All patients with clinically suspected dengue should have proper management to reduce the risk for hemorrhage and shock (11). If serologic testing indicates recent flavivirus infection that could be caused by either Zika or dengue virus, patients should be clinically managed for both infections because they might have been infected with either virus.

  8. Gravity Investigation in Area East of River Nile (Khartoum State)

    Institute of Scientific and Technical Information of China (English)

    Eldawi M G; Farwa A G

    2003-01-01

    The purpose of the study is to investigate the subsurface geology of the area. For quantitative interpretation of the resulting Bouguer anomalies, borehole data are explored. This is done along several profiles obtained from software program G. model C version 2. 2 No. 175. This program is based on two -dimensional mass distribution. The interpretation reveals two basinal features filling depressions in the basement complex named as Abu Harira basin and Kabbashi basin. They are structurally related to Khartoum basin. As a result, a geological/structural map of the area in east of the Nile is produced. The basinal features in the study area are considered as parts of the central Sudan (Khartoum basin) that had been subjected to several tectonic events that resulted in the formation of several fracture systems associated with block subsidence and formation of these basins.

  9. Ventilation rates indicate stress-coping styles in Nile tilapia.

    Science.gov (United States)

    Barreto, Rodrigo E; Volpato, Gilson L

    2011-12-01

    Behavioural responses to stress can form distinct profiles in a wide range of animals: proactive and reactive profiles or coping styles. Stress responsiveness can also differentiate between the behavioural profiles. The tendency to regain feed intake following transfer to a novel social-isolation tank (the speed of acclimation) can discriminate between proactive or reactive profiles. Consequently, differential stress responsiveness can be linked to this feeding behaviour trait. This study shows that ventilation rates of Nile tilapia, Oreochromis niloticus (L.), correlate with the rate of feeding resumption, following transfer to a novel social-isolation aquarium. Therefore, ventilation rate (VR) indicates coping styles; consequently, VR is a proxy for the way fish will deal with environmental challenges. PMID:22116283

  10. Blood cues induce antipredator behavior in Nile tilapia conspecifics.

    Directory of Open Access Journals (Sweden)

    Rodrigo Egydio Barreto

    Full Text Available In this study, we show that the fish Nile tilapia displays an antipredator response to chemical cues present in the blood of conspecifics. This is the first report of alarm response induced by blood-borne chemical cues in fish. There is a body of evidence showing that chemical cues from epidermal 'club' cells elicit an alarm reaction in fish. However, the chemical cues of these 'club' cells are restricted to certain species of fish. Thus, as a parsimonious explanation, we assume that an alarm response to blood cues is a generalized response among animals because it occurs in mammals, birds and protostomian animals. Moreover, our results suggest that researchers must use caution when studying chemically induced alarm reactions because it is difficult to separate club cell cues from traces of blood.

  11. Ventilation rates indicate stress-coping styles in Nile tilapia

    Indian Academy of Sciences (India)

    Rodrigo E Barreto; Gilson L Volpato

    2011-12-01

    Behavioural responses to stress can form distinct profiles in a wide range of animals: proactive and reactive profiles or coping styles. Stress responsiveness can also differentiate between the behavioural profiles. The tendency to regain feed intake following transfer to a novel social-isolation tank (the speed of acclimation) can discriminate between proactive or reactive profiles. Consequently, differential stress responsiveness can be linked to this feeding behaviour trait. This study shows that ventilation rates of Nile tilapia, Oreochromis niloticus (L.), correlate with the rate of feeding resumption, following transfer to a novel social-isolation aquarium. Therefore, ventilation rate (VR) indicates coping styles; consequently, VR is a proxy for the way fish will deal with environmental challenges.

  12. Hydrological characterization of watersheds in the Blue Nile Basin

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    S. G. Gebrehiwot

    2010-07-01

    Full Text Available We made a hydrological characterization of 32 watersheds (31–4350 km2 in the Blue Nile Basin, using data from a study of water and land resources in the Blue Nile Basin, Ethiopia published in 1964 by the US Bureau of Reclamation (USBR. The USBR document contains data on flow, climate, topography, geology, soil type, and land use for the period from 1959 to 1963. The aim of the study was to identify which combination of watershed variables best explain the variation in the hydrological regime, with special focus to low flow and, what kind of land use low flow might benefit from. Principal Component Analysis (PCA and Partial Least Square (PLS were used to analyze the relationship between hydrologic variables (total flow, maximum flow, minimum flow, runoff coefficient, and low flow index and 30 potential watershed variables. We found that three groups of watershed variables – climate and topography, geology and soil, and land use had almost equal influence on the variation in the hydrologic variables (R2 values ranging from 0.3 to 0.5. The individual variables which were selected based on statistical significance from all groups of explanatory variables were better in explaining the variation. Low flow was positively correlated most strongly to wetland, wood land, rainfall, luvisols, and alluvial soils. Low flow was negatively correlated to grazing land, bush land, tuffs/basalts, eutric-vertisols and riverine forest. We concluded that low flow benefits from the land use types that preserve soil quality and water storage, such as wetland, savannah and woodland, while it was lower in land use resulting in soil degradation. Therefore it provides support to the theory that some land use such as grassland, can promote higher low flow

  13. Hydrological characterization of watersheds in the Blue Nile Basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    S. G. Gebrehiwot

    2011-01-01

    Full Text Available Thirty-two watersheds (31–4350 km2, in the Blue Nile Basin, Ethiopia, were hydrologically characterized with data from a study of water and land resources by the US Department of Interior, Bureau of Reclamation (USBR published in 1964. The USBR document contains data on flow, topography, geology, soil type, and land use for the period 1959 to 1963. The aim of the study was to identify watershed variables best explaining the variation in the hydrological regime, with a special focus on low flows. Moreover, this study aimed to identify variables that may be susceptible to management policies for developing and securing water resources in dry periods. Principal Component Analysis (PCA and Partial Least Square (PLS were used to analyze the relationship between five hydrologic response variables (total flow, high flow, low flow, runoff coefficient, low flow index and 30 potential explanatory watershed variables. The explanatory watershed variables were classified into three groups: land use, climate and topography as well as geology and soil type. Each of the three groups had almost equal influence on the variation in hydrologic variables (R2 values ranging from 0.3 to 0.4. Specific variables from within each of the three groups of explanatory variables were better in explaining the variation. Low flow and low flow index were positively correlated to land use types woodland, dense wet forest and savannah grassland, whereas grazing land and bush land were negatively correlated. We concluded that extra care for preserving low flow should be taken on tuffs/basalts which comprise 52% of the Blue Nile Basin. Land use management plans should recognize that woodland, dense wet forest and savannah grassland can promote higher low flows, while grazing land diminishes low flows.

  14. Olympic Games Rio 2016 and the uninvited viruses: Potential consequences for Europe and North America

    Directory of Open Access Journals (Sweden)

    Salim Mattar

    2016-05-01

    Full Text Available In the Latin American tropics, we have witnessed the emergence of several pathogenic arboviruses in the last decade. These include Yellow Fever, West Nile virus, St. Louis encephalitis, Venezuelan equine encephalitis, Mayaro, Oropouche, Ilheus, and most recently, Chikungunya and Zika. Guillain-Barre syndrome (GBS, microcephaly and all the encephalitides, have been of concern to public health officials in Latin America since the arrival of emerging arboviruses. ¡Don‘t forget about dengue!

  15. RNA Secondary Structure in the Coding Region of Dengue Virus Type 2 Directs Translation Start Codon Selection and Is Required for Viral Replication

    OpenAIRE

    Clyde, Karen; Harris, Eva

    2006-01-01

    Dengue virus is a positive-strand RNA virus and a member of the genus Flavivirus, which includes West Nile, yellow fever, and tick-borne encephalitis viruses. Flavivirus genomes are translated as a single polyprotein that is subsequently cleaved into 10 proteins, the first of which is the viral capsid (C) protein. Dengue virus type 2 (DENV2) and other mosquito-borne flaviviruses initiate translation of C from a start codon in a suboptimal context and have multiple in-frame AUGs downstream. He...

  16. Dengue Virus Genome Uncoating Requires Ubiquitination

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    Laura A. Byk

    2016-06-01

    Full Text Available The process of genome release or uncoating after viral entry is one of the least-studied steps in the flavivirus life cycle. Flaviviruses are mainly arthropod-borne viruses, including emerging and reemerging pathogens such as dengue, Zika, and West Nile viruses. Currently, dengue virus is one of the most significant human viral pathogens transmitted by mosquitoes and is responsible for about 390 million infections every year around the world. Here, we examined for the first time molecular aspects of dengue virus genome uncoating. We followed the fate of the capsid protein and RNA genome early during infection and found that capsid is degraded after viral internalization by the host ubiquitin-proteasome system. However, proteasome activity and capsid degradation were not necessary to free the genome for initial viral translation. Unexpectedly, genome uncoating was blocked by inhibiting ubiquitination. Using different assays to bypass entry and evaluate the first rounds of viral translation, a narrow window of time during infection that requires ubiquitination but not proteasome activity was identified. In this regard, ubiquitin E1-activating enzyme inhibition was sufficient to stabilize the incoming viral genome in the cytoplasm of infected cells, causing its retention in either endosomes or nucleocapsids. Our data support a model in which dengue virus genome uncoating requires a nondegradative ubiquitination step, providing new insights into this crucial but understudied viral process.

  17. Dengue Virus Genome Uncoating Requires Ubiquitination

    Science.gov (United States)

    Byk, Laura A.; Iglesias, Néstor G.; De Maio, Federico A.; Gebhard, Leopoldo G.; Rossi, Mario

    2016-01-01

    ABSTRACT The process of genome release or uncoating after viral entry is one of the least-studied steps in the flavivirus life cycle. Flaviviruses are mainly arthropod-borne viruses, including emerging and reemerging pathogens such as dengue, Zika, and West Nile viruses. Currently, dengue virus is one of the most significant human viral pathogens transmitted by mosquitoes and is responsible for about 390 million infections every year around the world. Here, we examined for the first time molecular aspects of dengue virus genome uncoating. We followed the fate of the capsid protein and RNA genome early during infection and found that capsid is degraded after viral internalization by the host ubiquitin-proteasome system. However, proteasome activity and capsid degradation were not necessary to free the genome for initial viral translation. Unexpectedly, genome uncoating was blocked by inhibiting ubiquitination. Using different assays to bypass entry and evaluate the first rounds of viral translation, a narrow window of time during infection that requires ubiquitination but not proteasome activity was identified. In this regard, ubiquitin E1-activating enzyme inhibition was sufficient to stabilize the incoming viral genome in the cytoplasm of infected cells, causing its retention in either endosomes or nucleocapsids. Our data support a model in which dengue virus genome uncoating requires a nondegradative ubiquitination step, providing new insights into this crucial but understudied viral process. PMID:27353759

  18. Full-length sequencing and genomic characterization of Bagaza, Kedougou, and Zika viruses.

    Science.gov (United States)

    Kuno, G; Chang, G-J J

    2007-01-01

    Many members of the genus Flavivirus are the agents of important diseases of humans, livestock, and wildlife. Currently, no complete genome sequence is available for the three African viruses, Bagaza, Zika, and Kedougou viruses, each representing a distinct virus subgroup according to the latest virus classification. In this study, we obtained a complete genome sequence of each of those three viruses and characterized the open reading frames (ORFs) with respect to gene sizes, cleavage sites, potential glycosylation sites, distribution of cysteine residues, and unique motifs. The sequences of the three viruses were then scanned across the entire length of the ORF against available sequences of other African flaviviruses and selected reference viruses for genetic relatedness. The data collectively indicated that Kedougou virus was close to dengue viruses but nonetheless distinct, while Bagaza virus shared genetic relatedness with West Nile virus in several genomic regions. In the non-coding regions, it was found that a particular organizational pattern of conserved sequences in the 3' terminal region generally correlated with the current virus grouping.

  19. Zika Virus Infection and Microcephaly: Evidence for a Causal Link

    Directory of Open Access Journals (Sweden)

    Jin-Na Wang

    2016-10-01

    Full Text Available Zika virus (ZIKV is a flavivirus related to the Dengue, yellow fever and West Nile viruses. Since the explosive outbreaks of ZIKV in Latin America in 2015, a sudden increase in the number of microcephaly cases has been observed in infants of women who were pregnant when they contracted the virus. The severity of this condition raises grave concerns, and extensive studies on the possible link between ZIKV infection and microcephaly have been conducted. There is substantial evidence suggesting that there is a causal link between ZIKV and microcephaly, however, future studies are warranted to solidify this association. To summarize the most recent evidence on this issue and provide perspectives for future studies, we reviewed the literature to identify existing evidence of the causal link between ZIKV infection and microcephaly within research related to the epidemics, laboratory diagnosis, and possible mechanisms.

  20. Water balance modelling of the Nile River system to aid in understanding hydrologic interactions

    International Nuclear Information System (INIS)

    The importance of understanding the hydrology of the Nile Basin cannot be overstated. In this massive watershed, the interests of providing Nile countries with an adequate water supply competes with the need to protect unique and irreplaceable ecosystems like Lake Victoria and Lake Tana, the Equatorial lakes, and the Sudd swamp. Researchers worldwide have long studied various aspects of Nile Basin hydrology, from rainfall studies in the Ethiopian highlands to evaporation rates in Lake Nasser. An important aspect of the basin's hydrological cycle that has received less attention, however, has been the relative influence of groundwater in the basin. Groundwater plays an increasingly important role for Nile Basin countries. It is the source of water for irrigation and other uses in many parts of the basin; in some countries it provides large percentages of the urban water supply. Additionally, groundwater use is expected to increase significantly in the next decade, as is its vulnerability to pollution. However, limited information exists on the quantity and movement of groundwater in the Nile countries, particularly in relation to rivers, lakes, and wetlands - the surface waters - of the Nile system. A highly effective strategy for understanding interactions between surface water and groundwater is the use of water balance models. In their simplest form, water balances account for all the inputs and outputs of water in a given system, such as rainfall, evaporation, river flow, recharge to groundwater aquifers, and discharge of groundwater. Water balance models can be conducted on a variety of scales, from small headwater catchments to continental scale systems, such as the entire Nile Basin. The Isotope Hydrology Section is working with Nile countries on a project, funded by the Global Environment Facility (GEF) and implemented by the United Nations Development Programme (UNDP), entitled, 'Mainstreaming Groundwater Considerations into the Integrated Management of the