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  1. What's West Nile Virus?

    Science.gov (United States)

    ... for Educators Search English Español What's West Nile Virus? KidsHealth / For Kids / What's West Nile Virus? Print en español ¿Qué es el Virus del Nilo Occidental? What exactly is the West ...

  2. Enzootic transmission of yellow fever virus, Venezuela.

    Science.gov (United States)

    Auguste, Albert J; Lemey, Philippe; Bergren, Nicholas A; Giambalvo, Dileyvic; Moncada, Maria; Morón, Dulce; Hernandez, Rosa; Navarro, Juan-Carlos; Weaver, Scott C

    2015-01-01

    Phylogenetic analysis of yellow fever virus (YFV) strains isolated from Venezuela strongly supports YFV maintenance in situ in Venezuela, with evidence of regionally independent evolution within the country. However, there is considerable YFV movement from Brazil to Venezuela and between Trinidad and Venezuela.

  3. West Nile Virus Neuroinvasive Disease

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2009-07-01

    Full Text Available Epidemiological features of West Nile Virus (WNV disease among children (<18 years of age reported to the Centers for Disease Control and Prevention from 1999 through 2007 were analyzed and compared with those of adult WNV neuroinvasive disease (WNND, in a study at CDC&P, Fort Collins, CO.

  4. 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.

  5. 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 year),...

  6. 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 - 2017. In this Table, provisional cases of selected notifiable diseases (≥1,000 cases reported during the preceding year),...

  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 - 2016. In this Table, provisional* cases of selected† notifiable diseases (≥1,000 cases reported during the preceding...

  8. 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.

  9. West Nile virus: Immunity and pathogenesis

    NARCIS (Netherlands)

    S.M. Lim (Stephanie); P. Koraka (Penelope); A.D.M.E. Osterhaus (Albert); B.E.E. Martina (Byron)

    2011-01-01

    textabstractWest Nile virus (WNV) is a neurotropic, arthropod-borne flavivirus that is maintained in an enzootic cycle between mosquitoes and birds, but can also infect and cause disease in horses and humans. WNV is endemic in parts of Africa, Europe, the Middle East, and Asia, and since 1999 has

  10. Vaccines in Development against West Nile Virus

    Directory of Open Access Journals (Sweden)

    Frederic Tangy

    2013-09-01

    Full Text Available West Nile encephalitis emerged in 1999 in the United States, then rapidly spread through the North American continent causing severe disease in human and horses. Since then, outbreaks appeared in Europe, and in 2012, the United States experienced a new severe outbreak reporting a total of 5,387 cases of West Nile virus (WNV disease in humans, including 243 deaths. So far, no human vaccine is available to control new WNV outbreaks and to avoid worldwide spreading. In this review, we discuss the state-of-the-art of West Nile vaccine development and the potential of a novel safe and effective approach based on recombinant live attenuated measles virus (MV vaccine. MV vaccine is a live attenuated negative-stranded RNA virus proven as one of the safest, most stable and effective human vaccines. We previously described a vector derived from the Schwarz MV vaccine strain that stably expresses antigens from emerging arboviruses, such as dengue, West Nile or chikungunya viruses, and is strongly immunogenic in animal models, even in the presence of MV pre-existing immunity. A single administration of a recombinant MV vaccine expressing the secreted form of WNV envelope glycoprotein elicited protective immunity in mice and non-human primates as early as two weeks after immunization, indicating its potential as a human vaccine.

  11. 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.

  12. Asian genotype of Chikungunya virus circulating in Venezuela during 2014.

    Science.gov (United States)

    Camacho, Daría; Reyes, Jesús; Negredo, Ana; Hernández, Lourdes; Sánchez-Seco, María; Comach, Guillermo

    2017-10-01

    Chikungunya virus emerged on Saint-Martin Island in the Caribbean in late 2013. Since then in July of 2104 Venezuela reported autochthonous cases. This study reports the first phylogenetic characterization of CHIKV autochthonous cases in Venezuela, 2014. The phylogenetic analysis showed that the CHIKV circulating in Venezuela (Aragua state) belong to the Asian genotype (Caribbean clade) and it is related to viruses that circulated in the same year in the Caribbean. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Phylogenetic analysis of West Nile virus, Nuevo Leon State, Mexico.

    Science.gov (United States)

    Blitvich, Bradley J; Fernández-Salas, Ildefonso; Contreras-Cordero, Juan F; Loroño-Pino, María A; Marlenee, Nicole L; Díaz, Francisco J; González-Rojas, José I; Obregón-Martínez, Nelson; Chiu-García, Jorge A; Black, William C; Beaty, Barry J

    2004-07-01

    West Nile virus RNA was detected in brain tissue from a horse that died in June 2003 in Nuevo Leon State, Mexico. Nucleotide sequencing and phylogenetic analysis of the premembrane and envelope genes showed that the virus was most closely related to West Nile virus isolates collected in Texas in 2002.

  14. Migratory birds and West Nile virus

    Czech Academy of Sciences Publication Activity Database

    Rappole, J. H.; Hubálek, Zdeněk

    2003-01-01

    Roč. 94, s1 (2003), s. 47-58 ISSN 1364-5072. [Conference of Society for Applied Microbiology (U.K.) "Pathogens in the Environment and Changing Ecosystems". Nottingham, 08.07.2002-11.07.2002] Institutional research plan: CEZ:AV0Z6093917 Keywords : West Nile virus * bird migration Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 1.743, year: 2003

  15. Seasonal abundance and molecular identification of West Nile virus ...

    African Journals Online (AJOL)

    Seasonal abundance and molecular identification of West Nile virus vectors, Culex pipens and Culex ... Background: West Nile virus (WNV) infection, is an arbovirus infection with high morbidity and mortality, the vector respon- sible for both human ... Major diseases transmitted are known as Arboviral dis- eases because ...

  16. West Nile virus ecology in a tropical ecosystem in Guatemala.

    Science.gov (United States)

    Morales-Betoulle, Maria E; Komar, Nicholas; Panella, Nicholas A; Alvarez, Danilo; López, María R; Betoulle, Jean-Luc; Sosa, Silvia M; Müller, María L; Kilpatrick, A Marm; Lanciotti, Robert S; Johnson, Barbara W; Powers, Ann M; Cordón-Rosales, Celia

    2013-01-01

    West Nile virus ecology has yet to be rigorously investigated in the Caribbean Basin. We identified a transmission focus in Puerto Barrios, Guatemala, and established systematic monitoring of avian abundance and infection, seroconversions in domestic poultry, and viral infections in mosquitoes. West Nile virus transmission was detected annually between May and October from 2005 to 2008. High temperature and low rainfall enhanced the probability of chicken seroconversions, which occurred in both urban and rural sites. West Nile virus was isolated from Culex quinquefasciatus and to a lesser extent, from Culex mollis/Culex inflictus, but not from the most abundant Culex mosquito, Culex nigripalpus. A calculation that combined avian abundance, seroprevalence, and vertebrate reservoir competence suggested that great-tailed grackle (Quiscalus mexicanus) is the major amplifying host in this ecosystem. West Nile virus transmission reached moderate levels in sentinel chickens during 2007, but less than that observed during outbreaks of human disease attributed to West Nile virus in the United States.

  17. [Zika virus: Another emerging arbovirus in Venezuela?].

    Science.gov (United States)

    Valero Nereida

    2015-09-01

    Current health conditions of Venezuela, together with the tropical proliferation of different types of Aedes (aegypti and albopictus), suggest the arrival to this country of ZIKA virus (ZIKV). The Pan American Health Organization urges Latin American countries to take measures to prevent the ZIKV entry and advises that these measures must be designed to detect the introduction of ZIKV in an area, track its spread and actively monitor the disease. In Venezuela and other Latin-American countries, where endemicity is high for other arboviruses such as dengue arid chikungunya, health authorities should strengthen their surveillance systems to detect early and timely introduction of ZIKV ap.d refine diagnostic methods to confirm the infection rate; however, the high incidence of cases due those viral agents reflects weakened and poorly timed insensitive monitoring systems, as well as, poor vector control measures, arising the questions: will this arbovirus pop in our country, will it set as the other as edemicepidemic and lead to alter their clinical behavior and severity of the disease?

  18. West Nile virus in overwintering mosquitoes, central Europe

    Czech Academy of Sciences Publication Activity Database

    Rudolf, I.; Betášová, L.; Blažejová, H.; Venclíková, Kristýna; Straková, P.; Šebesta, O.; Mendel, J.; Bakonyi, T.; Schaffner, F.; Nowotny, N.; Hubálek, Z.

    2017-01-01

    Roč. 10, 2 October (2017), s. 1-4, č. článku 452. ISSN 1756-3305 Institutional support: RVO:61389013 Keywords : West Nile fever * West Nile virus * Flavivirus Subject RIV: EE - Microbiology, Virology OBOR OECD: Virology Impact factor: 3.080, year: 2016

  19. 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 1,000...

  20. West Nile virus infection of birds, Mexico.

    Science.gov (United States)

    Guerrero-Sánchez, Sergio; Cuevas-Romero, Sandra; Nemeth, Nicole M; Trujillo-Olivera, María Teresa Jesús; Worwa, Gabriella; Dupuis, Alan; Brault, Aaron C; Kramer, Laura D; Komar, Nicholas; Estrada-Franco, José Guillermo

    2011-12-01

    West Nile virus (WNV) has caused disease in humans, equids, and birds at lower frequency in Mexico than in the United States. We hypothesized that the seemingly reduced virulence in Mexico was caused by attenuation of the Tabasco strain from southeastern Mexico, resulting in lower viremia than that caused by the Tecate strain from the more northern location of Baja California. During 2006-2008, we tested this hypothesis in candidate avian amplifying hosts: domestic chickens, rock pigeons, house sparrows, great-tailed grackles, and clay-colored thrushes. Only great-tailed grackles and house sparrows were competent amplifying hosts for both strains, and deaths occurred in each species. Tecate strain viremia levels were higher for thrushes. Both strains produced low-level viremia in pigeons and chickens. Our results suggest that certain avian hosts within Mexico are competent for efficient amplification of both northern and southern WNV strains and that both strains likely contribute to bird deaths.

  1. West Nile virus meningitis in a patient with human immunodeficiency virus type 1 infection

    Directory of Open Access Journals (Sweden)

    D. Pilalas

    2017-09-01

    Full Text Available The emergence of West Nile virus lineage 2 in central Macedonia, Greece, in 2010 resulted in large outbreaks for 5 consecutive years. We report a case of viral meningitis in an individual infected with human immunodeficiency virus type 1, which preceded the recognition of the outbreak and was confirmed retrospectively as West Nile virus neuroinvasive disease.

  2. 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.

  3. West Nile virus in overwintering mosquitoes, central Europe

    Czech Academy of Sciences Publication Activity Database

    Rudolf, Ivo; Betášová, Lenka; Blažejová, Hana; Venclíková, Kristýna; Straková, Petra; Šebesta, Oldřich; Mendel, Jan; Bakonyi, T.; Schaffner, F.; Nowotny, N.; Hubálek, Zdeněk

    2017-01-01

    Roč. 10, č. 452 (2017), č. článku 452. ISSN 1756-3305 R&D Projects: GA ČR(CZ) GA16-20054S EU Projects: European Commission(XE) 261504 - EDENEXT Institutional support: RVO:68081766 Keywords : West Nile fever * West Nile virus * Flavivirus * Hibernation * Overwintering * Culex pipiens * Anopheles maculipennis * Culiseta annulata * Czech Republic Subject RIV: EE - Microbiology, Virology OBOR OECD: Parasitology Impact factor: 3.080, year: 2016

  4. West Nile Virus Encephalitis in a Barbary Macaque (Macaca sylvanus)

    Science.gov (United States)

    Barker, Ian K.; Crawshaw, Graham J.; Bertelsen, Mads F.; Drebot, Michael A.; Andonova, Maya

    2004-01-01

    An aged Barbary ape (Macaca sylvanus) at the Toronto Zoo became infected with naturally acquired West Nile virus (WNV) encephalitis that caused neurologic signs, which, associated with other medical problems, led to euthanasia. The diagnosis was based on immunohistochemical assay of brain lesions, reverse transcriptase–polymerase chain reaction, and virus isolation. PMID:15200866

  5. A Review of Vaccine Approaches for West Nile Virus

    Directory of Open Access Journals (Sweden)

    Konstantin G. Kousoulas

    2013-09-01

    Full Text Available The West Nile virus (WNC first appeared in North America in 1999. The North American lineages of WNV were characterized by the presence of neuroinvasive and neurovirulent strains causing disease and death in humans, birds and horses. The 2012 WNV season in the United States saw a massive spike in the number of neuroinvasive cases and deaths similar to what was seen in the 2002–2003 season, according to the West Nile virus disease cases and deaths reported to the CDC by year and clinical presentation, 1999–2012, by ArboNET (Arboviral Diseases Branch, Centers for Disease Control and Prevention. In addition, the establishment and recent spread of lineage II WNV virus strains into Western Europe and the presence of neurovirulent and neuroinvasive strains among them is a cause of major concern. This review discusses the advances in the development of vaccines and biologicals to combat human and veterinary West Nile disease.

  6. Neuromuscular Manifestations of West Nile Virus Infection

    Directory of Open Access Journals (Sweden)

    A. Arturo eLeis

    2012-03-01

    Full Text Available The most common neuromuscular manifestation of West Nile virus (WNV infection is a poliomyelitis syndrome with asymmetric paralysis variably involving one (monoparesis to four limbs (quadriparesis, with or without brainstem involvement and respiratory failure. This syndrome of acute flaccid paralysis may occur without overt fever or meningoencephalitis. Although involvement of anterior horn cells in the spinal cord and motor neurons in the brainstem are the major sites of pathology responsible for neuromuscular signs, inflammation also may involve skeletal or cardiac muscle (myositis, myocarditis, motor axons (polyradiculitis, peripheral nerve (Guillain-Barré syndrome, brachial plexopathy. In addition, involvement of spinal sympathetic neurons and ganglia provides a plausible explanation for autonomic instability seen in some patients. Many patients also experience prolonged subjective generalized weakness and disabling fatigue. Despite recent evidence that WNV may persist long term in the central nervous system or periphery in animals, the evidence in humans is controversial. WNV persistence would be of great concern in immunosuppressed patients or in those with prolonged or recurrent symptoms. Support for the contention that WNV can lead to autoimmune disease arises from reports of patients presenting with various neuromuscular diseases that presumably involve autoimmune mechanisms (GBS, other demyelinating neu¬ropathies, myasthenia gravis, brachial plexopathies, stiff-person syndrome, and delayed or recurrent symptoms. Although there is no specific treatment or vaccine currently approved in humans, and the standard remains supportive care, drugs that can alter the cascade of immunobiochemical events leading to neuronal death may be potentially useful (high-dose corticosteroids, interferon preparations, and intravenous immune globulin containing WNV-specific antibodies. Human experience with these agents seems promising based on anecdotal

  7. 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.

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

    Czech Academy of Sciences Publication Activity Database

    Bakonyi, T.; Gaydon, G. K.; Schwing, R.; Vogl, W.; Häbich, A.-C.; Thaller, D.; Weissenböck, H.; Rudolf, Ivo; Hubálek, Zdeněk; Nowotny, N.

    2016-01-01

    Roč. 183, February (2016), s. 135-139 ISSN 0378-1135 EU Projects: European Commission(XE) 261504 - EDENEXT; European Commission(XE) 261391 - EUROWESTNILE Institutional support: RVO:68081766 Keywords : West Nile virus * Lineage 2 * Kea * Nestor notabilis * Psittaciformes * Persistent infection * Austria Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 2.628, year: 2016

  9. Modelling West Nile virus transmission risk in Europe

    NARCIS (Netherlands)

    Vogels, Chantal B.F.; Hartemink, Nienke; Koenraadt, Constantianus J.M.

    2017-01-01

    West Nile virus (WNV) is a mosquito-borne flavivirus which has caused repeated outbreaks in humans in southern and central Europe, but thus far not in northern Europe. The main mosquito vector for WNV, Culex pipiens, consists of two behaviourally distinct biotypes, pipiens and molestus, which can

  10. [Birds, mosquitoes and West Nile virus: little risk of West Nile fever in the Netherlands].

    Science.gov (United States)

    Duijster, Janneke W; Stroo, C J Arjan; Braks, Marieta A H

    2016-01-01

    Due to increased incidence of West Nile fever (WNF) in Europe and the rapid spread of West Nile virus (WNV) in the US, it is commonly thought that it will only be a matter of time before WNV reaches the Netherlands. However, assessing whether WNV is really a threat to the Dutch population is challenging, due to the numerous factors affecting transmission of the virus. Some of these factors are known to limit the risk of WNF in the Netherlands. This risk is determined by the interaction between the pathogen (WNV), the vectors (Culex mosquitoes), the reservoirs (birds) and the exposure of humans to infected mosquitoes. In this paper, we discuss the factors influencing introduction, establishment and spread of WNV in the Netherlands. The probability that each of these three phases will occur in the Netherlands is currently relatively small, as is the risk of WNF infection in humans in the Netherlands.

  11. West Nile virus infection and diplopia: a case report and review of literature

    Directory of Open Access Journals (Sweden)

    Dahal U

    2013-05-01

    Full Text Available Udip Dahal,1 Neville Mobarakai,1 Dikshya Sharma,2 Bandana Pathak11Department of Medicine, Staten Island University Hospital, Staten Island, New York, NY, USA; 2Department of Medicine, Nepalgunj Medical College, Banke, NepalAbstract: West Nile virus is a neurotropic virus transmitted to humans via an infected mosquito bite. The increase in the incidences and fatalities of West Nile virus disease has made West Nile virus an important pathogen. Here we describe a case of a 65-year-old man with fever and diplopia presenting to the emergency department during a fall season and who was later diagnosed with West Nile virus infection. Diplopia is an uncommon manifestation of West Nile virus and recognition of the different modes of presentation, especially the uncommon ones like diplopia, will aid in the diagnosis of this emerging infectious disease.Keywords: West Nile virus, diplopia, ocular manifestations, infectious disease, Flaviviridae

  12. Alexander the Great and West Nile virus encephalitis.

    Science.gov (United States)

    Marr, John S; Calisher, Charles H

    2003-12-01

    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 behavior of ravens is reminiscent of avian illness and death weeks before the first human cases of West Nile virus infection were identified in the United States. We posit that Alexander may have died of West Nile virus encephalitis.

  13. Import of West Nile virus infection in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk; Lukáčová, L.; Halouzka, Jiří; Širůček, P.; Januška, J.; Přecechtělová, J.; Procházka, P.

    2006-01-01

    Roč. 21, č. 4 (2006), s. 323-324 ISSN 0393-2990 R&D Projects: GA ČR GA206/03/0726 EU Projects: European Commission(XE) 10284 - EDEN Institutional research plan: CEZ:AV0Z60930519 Keywords : West Nile virus * CNS infection * Flavivirus Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 1.605, year: 2006

  14. Transmission of Guanarito and Pirital Viruses among Wild Rodents, Venezuela

    Science.gov (United States)

    Milazzo, Mary L.; Cajimat, Maria N.B.; Duno, Gloria; Duno, Freddy; Utrera, Antonio

    2011-01-01

    Samples from rodents captured on a farm in Venezuela in February 1997 were tested for arenavirus, antibody against Guanarito virus (GTOV), and antibody against Pirital virus (PIRV). Thirty-one (48.4%) of 64 short-tailed cane mice (Zygodontomys brevicauda) were infected with GTOV, 1 Alston’s cotton rat (Sigmodon alstoni) was infected with GTOV, and 36 (64.3%) of 56 other Alston’s cotton rats were infected with PIRV. The results of analyses of field and laboratory data suggested that horizontal transmission is the dominant mode of GTOV transmission in Z. brevicauda mice and that vertical transmission is an important mode of PIRV transmission in S. alstoni rats. The results also suggested that bodily secretions and excretions from most GTOV-infected short-tailed cane mice and most PIRV-infected Alston’s cotton rats may transmit the viruses to humans. PMID:22172205

  15. Serologic evidence of West Nile virus and Usutu virus infections in Eurasian coots in the Netherlands

    NARCIS (Netherlands)

    Lim, S.M.; Geervliet, M.; Verhagen, J.H.; Müskens, G.J.D.M.; Majoor, F.A.; Osterhaus, Albert D.M.E.; Martina, Byron E.

    2018-01-01

    West Nile virus (WNV) and Usutu virus (USUV) are arboviruses that are maintained in enzootic transmission cycles between mosquitoes and birds and are occasionally transmitted to mammals. As arboviruses are currently expanding their geographic range and emerging in often unpredictable locations,

  16. Co-circulation of Usutu virus and West Nile virus in a reed bed ecosystem

    Czech Academy of Sciences Publication Activity Database

    Rudolf, Ivo; Bakonyi, T.; Šebesta, Oldřich; Mendel, Jan; Peško, Juraj; Betášová, Lenka; Blažejová, Hana; Venclíková, Kristýna; Straková, Petra; Nowotny, N.; Hubálek, Zdeněk

    2015-01-01

    Roč. 8, č. 520 (2015), s. 520 ISSN 1756-3305 EU Projects: European Commission(XE) 261504 - EDENEXT Institutional support: RVO:68081766 Keywords : Culex modestus * Usutu virus * West Nile virus * Flavivirus * Arbovirus * Surveillance * Mosquitoes Subject RIV: EE - Microbiology, Virology Impact factor: 3.234, year: 2015

  17. 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

  18. 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.

  19. 78 FR 16505 - Prospective Grant of Exclusive License: Chimeric West Nile/Dengue Viruses

    Science.gov (United States)

    2013-03-15

    ... Grant of Exclusive License: Chimeric West Nile/Dengue Viruses AGENCY: Centers for Disease Control and.... Provisional Application 61/049,342, filed 4/30/2008, entitled ``Engineered, Chimeric West Nile/Dengue Viruses;'' PCT Application PCT/US2009/041824, filed 4/27/2009, entitled ``Engineered, Chimeric WN/Flavivirus as...

  20. 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.

  1. Venezuela.

    Science.gov (United States)

    1987-04-01

    The background notes by the U.S. State Department on Venezuela emphasize the unique economic conditions in this oil-rich nation, and include information on its people, geography, history, government politics, defense and foreign relations. Venezuela, located on the north coast of South America, has 17,791,000 people, growing at a rate of 2.7%. Infant mortality is 2.7/1000, and life expectancy is 70 years. Geography ranges from the scarcely populated highlands between the Orinoco river and Guyana, the Orinoco plains, to the populated Andes mountains and coast. 80% of the population is urban. Literacy is a priority at 88.4%; Technical and university education is increasing; emigration from other countries is common because of relatively good working conditions. Venezuela has a long history of self government, having become independent in 1921. Now the democratic constitutional government is effective in improving both internal and regional development and human rights. The economy is based on oil production and refining, as well as steel and aluminum, all nationalized industries. Self-sufficiency in agriculture is a national goal. Because of the rapid population growth rate, however, per capita income and GNP are stagnating.

  2. A recombinant influenza a virus expressing domain III of west nile virus induces protective immune responses against influenza and west nile virus

    NARCIS (Netherlands)

    B.E.E. Martina (Byron); P. van den Doel (Petra); P. Koraka (Penelope); G. van Amerongen (Geert); G. Spohn (Gunther); B.L. Haagmans (Bart); L.B.V. Provacia (Lisette); A.D.M.E. Osterhaus (Albert); G.F. Rimmelzwaan (Guus)

    2011-01-01

    textabstractWest Nile virus (WNV) continues to circulate in the USA and forms a threat to the rest of the Western hemisphere. Since methods for the treatment of WNV infections are not available, there is a need for the development of safe and effective vaccines. Here, we describe the construction of

  3. Hepatitis C virus infection in hemodialysis patients in Maracaibo, Venezuela

    Directory of Open Access Journals (Sweden)

    Francisca Monsalve-Castillo

    2012-02-01

    Full Text Available Over a two year period, the incidence of hepatitis C virus (HCV infection was evaluated in 29 hemodialysis patients, aged between 15 and 75 years (mean ± SD: 45 ± 39.5 years, from the University Hospital Hemodyalisis Unit, Maracaibo, Zulia State, Venezuela. Anti-HCV antibodies were determined using a fourth generation ELISA (Innotest HCV Ab IV kit and positive blood samples were tested using a recombinant assay kit (Inno-LIA HCV Ab III, both kits from Innogenetics N.V., Belgium. The findings indicate a lack of HCV seroconversion in the hemodialysis patients over the study period, confirmed by the recombinant assay. Risk factors for HCV infection were 0.3270 (95% confidence interval: 0.01323-8.080 in patients undergoing hemodialysis. The findings suggest a lack of significant sources for HCV infection due to the preventive measures to avoid its transmission in the hemodialysis unit.

  4. West Nile Virus workshop: scientific considerations for tissue donors.

    Science.gov (United States)

    Brubaker, Scott A; Robert Rigney, P

    2012-08-01

    This report contains selected excerpts, presented as a summary, from a public workshop sponsored by the American Association of Tissue Banks (AATB) held to discuss West Nile Virus (WNV) and scientific considerations for tissue donors. The daylong workshop was held 9 July 2010 at the Ritz-Carlton Hotel at Tyson's Corner in McLean, Virginia, United States (U.S.). The workshop was designed to determine and discuss scientific information that is known, and what is not known, regarding WNV infection and transmission. The goal is to determine how to fill gaps in knowledge of WNV and tissue donation and transplantation by pursuing relevant scientific studies. This information should ultimately support decisions leading to appropriate tissue donor screening and testing considerations. Discussion topics were related to identifying these gaps and determining possible solutions. Workshop participants included subject-matter experts from the U.S. Food and Drug Administration, the Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Health Canada, the Public Health Agency of Canada, AATB-accredited tissue banks including reproductive tissue banks, accredited eye banks of the Eye Bank Association of America, testing laboratories, and infectious disease and organ transplantation professionals. After all presentations concluded, a panel addressed this question: "What are the scientific considerations for tissue donors and what research could be performed to address those considerations?" The slide presentations from the workshop are available at: http://www.aatb.org/2010-West-Nile-Virus-Workshop-Presentations.

  5. West Nile virus and North America: an unfolding story.

    Science.gov (United States)

    Glaser, A

    2004-08-01

    Before the introduction of the West Nile virus (WNV) into the United States of America (USA) in 1999, conditions in North America were ideal for an arboviral epidemic. Such factors as the large, susceptible and non-immune animal and human populations, the presence of competent vectors, increasing international travel and commerce, existing methods for rapid dissemination and an ill-prepared animal and public health infrastructure all combined to create the essential elements for a severe animal and public health crisis--the 'perfect microbial storm'. The introduction of WNV into New York City was the final factor, serving as the catalyst to initiate one of the most significant epidemics in the USA. The spread of WNV across the country resulted in very large populations of wildlife, equines and people being exposed and infected. The epidemic is still not fully understood and its character continues to change and adapt. The recent recognition of a number of non-vector modes of transmission has revealed the disease as a greater threat and more difficult to control than first thought. West Nile virus gives every indication that it will become a permanent part of the 'medical landscape' of the USA, continuing to threaten wildlife, domestic animals and humans as a now endemic disease. This paper discusses the features of this extraordinary epidemic, and emphasises the need for an integrated surveillance system, greater diagnostic capacity and improved control strategies.

  6. Biological and phylogenetic characterization of a genotype VII Newcastle disease virus from Venezuela: Efficacy of vaccination

    Science.gov (United States)

    Here we describe the characterization a virulent genotype VII Newcastle disease virus (NDV) from Venezuela and evaluate the efficacy of heterologous genotype commercial vaccination under field and controlled rearing conditions. Biological pathotyping and molecular analysis were applied. Results sh...

  7. Indigenous West Nile virus infections in horses in Albania.

    Science.gov (United States)

    Berxholi, K; Ziegler, U; Rexhepi, A; Schmidt, K; Mertens, M; Korro, K; Cuko, A; Angenvoort, J; Groschup, M H

    2013-11-01

    Serum samples collected from 167 equines of 12 districts in Albania were tested for West Nile virus-specific antibodies by enzyme-linked immunosorbent assay and virus neutralization assay, using WNV lineage 1 and 2. In addition, 95 bird serum samples from Albania and 29 horse samples from Kosovo were tested in ELISA. An overall seroprevalence rate of 22% was found in horses from Albania, whereas no specific antibodies were found in the equine samples from Kosovo and the bird samples. This is the first report indicating WNV infections in animals in Albania, and the first reported seroprevalence study conducted for Kosovo. These results provide evidence for widespread infections of WNV in Albania. © 2013 Blackwell Verlag GmbH.

  8. A Mouse Model of Chronic West Nile Virus Disease.

    Directory of Open Access Journals (Sweden)

    Jessica B Graham

    2016-11-01

    Full Text Available Infection with West Nile virus (WNV leads to a range of disease outcomes, including chronic infection, though lack of a robust mouse model of chronic WNV infection has precluded identification of the immune events contributing to persistent infection. Using the Collaborative Cross, a population of recombinant inbred mouse strains with high levels of standing genetic variation, we have identified a mouse model of persistent WNV disease, with persistence of viral loads within the brain. Compared to lines exhibiting no disease or marked disease, the F1 cross CC(032x013F1 displays a strong immunoregulatory signature upon infection that correlates with restraint of the WNV-directed cytolytic response. We hypothesize that this regulatory T cell response sufficiently restrains the immune response such that a chronic infection can be maintained in the CNS. Use of this new mouse model of chronic neuroinvasive virus will be critical in developing improved strategies to prevent prolonged disease in humans.

  9. Globalization, land use and the invasion of West Nile virus

    Science.gov (United States)

    Kilpatrick, A. Marm

    2012-01-01

    Many invasive species that have been spread through the globalization of trade and travel are infectious pathogens. A paradigmatic case is the introduction of West Nile virus (WNV) into North America in 1999. A decade of research on the ecology and evolution of WNV includes three findings that provide insight into the outcome of future viral introductions. First, WNV transmission in North America is highest in urbanized and agricultural habitats, in part because the hosts and vectors of WNV are abundant in human-modified areas. Second, after its introduction, the virus quickly adapted to infect local mosquito vectors more efficiently than the originally introduced strain. Third, highly focused feeding patterns of the mosquito vectors of WNV result in unexpected host species being important for transmission. These findings provide a framework for predicting and preventing the emergence of foreign vector-borne pathogens. PMID:22021850

  10. Interventions Against West Nile Virus, Rift Valley Fever Virus, and Crimean-Congo Hemorrhagic Fever Virus: Where Are We?

    NARCIS (Netherlands)

    Kortekaas, J.A.; Ergonul, O.; Moormann, R.J.M.

    2010-01-01

    ARBO-ZOONET is an international network financed by the European Commission's seventh framework program. The major goal of this initiative is capacity building for the control of emerging viral vector-borne zoonotic diseases, with a clear focus on West Nile virus, Rift Valley fever virus, and

  11. Characterization of antigenetic serotypes from the dengue virus in Venezuela by means of Grid Computing.

    Science.gov (United States)

    Isea, Raúl; Montes, Esther; Rubio-Montero, Antonio J; Rosales, José D; Rodríguez-Pascual, Manuel A; Mayo, Rafael

    2010-01-01

    This work determines the molecular epidemiology of dengue virus in Venezuela by means of phylogenetic calculations performed on the EELA-2 Grid infrastructure with the PhyloGrid application, an open source tool that allows users performing phylogeny reconstruction in their research. In this study, a total of 132 E nucleotide gene sequences of dengue virus from Venezuela recorded in GenBank(R) have been processed in order to reproduce and validate the topology described in the literature.

  12. 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...

  13. West Nile virus infection in horses, Indian ocean.

    Science.gov (United States)

    Cardinale, E; Bernard, C; Lecollinet, S; Rakotoharinome, V M; Ravaomanana, J; Roger, M; Olive, M M; Meenowa, D; Jaumally, M R; Melanie, J; Héraud, J M; Zientara, S; Cêtre-Sossah, C

    2017-08-01

    The circulation of West Nile virus (WNV) in horses was investigated in the Southwest Indian ocean. In 2010, blood samples were collected from a total of 303 horses originating from Madagascar, Mauritius, Reunion and the Seychelles and tested for WNV-specific antibodies. An overall seroprevalence of 27.39% was detected in the Indian Ocean with the highest WNV antibody prevalence of 46.22% (95% CI: [37.4-55.2%]) in Madagascar. The age and origin of the horses were found to be associated with the WNV infection risk. This paper presents the first seroprevalence study investigating WN fever in horses in the Southwest Indian Ocean area and indicates a potential risk of infection for humans and animals. In order to gain a better understanding of WN transmission cycles, WNV surveillance needs to be implemented in each of the countries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. 21 CFR 866.3940 - West Nile virus serological reagents.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3940 West Nile... detection aids in the clinical laboratory diagnosis of viral meningitis/encephalitis caused by West Nile...

  15. West Nile Virus lineage-2 in Culex specimens from Iran.

    Science.gov (United States)

    Shahhosseini, Nariman; Chinikar, Sadegh; Moosa-Kazemi, Seyed Hassan; Sedaghat, Mohammad Mehdi; Kayedi, Mohammad Hassan; Lühken, Renke; Schmidt-Chanasit, Jonas

    2017-10-01

    Screening of mosquitoes for viruses is an important forecasting tool for emerging and re-emerging arboviruses. Iran has been known to harbour medically important arboviruses such as West Nile virus (WNV) and dengue virus (DENV) based on seroepidemiological data. However, there are no data about the potential mosquito vectors for arboviruses in Iran. This study was performed to provide mosquito and arbovirus data from Iran. A total of 32 317 mosquitos were collected at 16 sites in five provinces of Iran in 2015 and 2016. RT-PCR for detection of flaviviruses was performed. The PCR amplicons were sequenced, and 109 WNV sequences, including one obtained in this study, were used for phylogenetic analyses. The 32 317 mosquito specimens belonging to 25 species were morphologically distinguished and distributed into 1222 pools. Culex pipiens s.l. comprised 56.429%. One mosquito pool (0.08%), containing 46 unfed Cx. pipiens pipiens form pipiens (Cpp) captured in August 2015, was positive for flavivirus RNA. Subsequent sequencing and phylogenetic analyses revealed that the detected Iranian WNV strain belongs to lineage 2 and clusters with a strain recently detected in humans. No flaviviruses other than WNV were detected in the mosquito pools. Cpp could be a vector for WNV in Iran. Our findings indicate recent circulation of WNV lineage-2 strain in Iran and provide a solid base for more targeted arbovirus surveillance programs. © 2017 John Wiley & Sons Ltd.

  16. 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.

  17. Mechanism of West Nile Virus Neuroinvasion: A Critical Appraisal

    Directory of Open Access Journals (Sweden)

    Willy W. Suen

    2014-07-01

    Full Text Available West Nile virus (WNV is an important emerging neurotropic virus, responsible for increasingly severe encephalitis outbreaks in humans and horses worldwide. However, the mechanism by which the virus gains entry to the brain (neuroinvasion remains poorly understood. Hypotheses of hematogenous and transneural entry have been proposed for WNV neuroinvasion, which revolve mainly around the concepts of blood-brain barrier (BBB disruption and retrograde axonal transport, respectively. However, an over‑representation of in vitro studies without adequate in vivo validation continues to obscure our understanding of the mechanism(s. Furthermore, WNV infection in the current rodent models does not generate a similar viremia and character of CNS infection, as seen in the common target hosts, humans and horses. These differences ultimately question the applicability of rodent models for pathogenesis investigations. Finally, the role of several barriers against CNS insults, such as the blood-cerebrospinal fluid (CSF, the CSF-brain and the blood-spinal cord barriers, remain largely unexplored, highlighting the infancy of this field. In this review, a systematic and critical appraisal of the current evidence relevant to the possible mechanism(s of WNV neuroinvasion is conducted.

  18. First molecular analysis of West Nile virus during the 2013 outbreak in Croatia.

    Science.gov (United States)

    Kurolt, Ivan C; Krajinović, Vladimir; Topić, Antea; Kuzman, Ilija; Baršić, Bruno; Markotić, Alemka

    2014-08-30

    This is the second subsequent year of West Nile neuroinvasive disease (WNND) outbreak in Croatia. Between July and October 2013, 22 patients presented with symptoms of WNND: all with meningitis and 18 additionally with encephalitis. In contrast to 2012, where six autochthonous infections were confirmed in eastern Croatia, the majority of this year's cases occurred in and around the city of Zagreb, where no West Nile virus infections have been observed before. Viral RNA was recovered from two patients and phylogenetic analyses revealed West Nile virus lineage 2. This represents the first molecular characterization and phylogenetic analysis of the circulating West Nile virus strain in Croatia. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Pletnev, Alexander G.; St Claire, Marisa; Elkins, Randy; Speicher, Jim; Murphy, Brian R.; Chanock, Robert M.

    2003-01-01

    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

  20. West Nile Virus: Seroprevalence in Animals in Palestine and Israel.

    Science.gov (United States)

    Azmi, Kifaya; Tirosh-Levy, Sharon; Manasrah, Mu'taz; Mizrahi, Rotem; Nasereddin, Abed; Al-Jawabreh, Amer; Ereqat, Suheir; Abdeen, Ziad; Lustig, Yaniv; Gelman, Boris; Schvartz, Gili; Steinman, Amir

    2017-08-01

    West Nile virus (WNV) epidemiological situation in Israel and Palestine, due to their unique location, draws attention following to the global spread of West Nile fever (WNF). Although much information is available from Israel on clinical cases and prevalence of WNV, clinical cases are rarely reported in Palestine, and prevalence is not known. The objectives of this study were to determine WNV seroprevalence in various domestic animals in Palestine and to reevaluate current seroprevalence, force of infection, and risk factors for WNV exposure in horses in Israel. Sera samples were collected from 717 animals from Palestine and Israel (460 horses, 124 donkeys, 3 mules, 50 goats, 45 sheep, and 35 camels). Two hundred and ten horses were sampled twice. The level of WNV antibodies was determined using commercial Enzyme-linked Immunosorbent Assay (ELISA) Kit. Seroprevalence in equids was 73%. Seroprevalence in Israel (84.6%) was significantly higher than in Palestine (48.6%). Seroprevalence in horses (82.6%) was significantly higher than in donkeys and mules (39.3%). Multivariable statistical analysis showed that geographical area, landscape features (altitude), environmental factors (land surface temperature during the day [LSTD]), species, and age significantly influenced WNV seroprevalence. Fourteen of 95 (14.7%) sheep and goats and 14/35 camels (40%) sampled in Palestine were seropositive for WNV. Of the horses that were sampled twice, 82.8% were seropositive for WNV at the first sampling, and all remained seropositive. Three of the seronegative horses, all from Palestine, converted to positive when resampled (8.5%). The results indicate that domestic animals in Palestine were infected with WNV in the past, and the seroconversion indicates that WNV was circulating in Palestine in the summer of 2014. Control measures to prevent human infection should be implemented in Palestine. Anti WNV antibodies in domestic animals suggest that those species can be used as

  1. Transmission dynamics and changing epidemiology of West Nile virus.

    Science.gov (United States)

    Blitvich, Bradley J

    2008-06-01

    West Nile virus (WNV) is a flavivirus that is maintained in a bird-mosquito transmission cycle. Humans, horses and other non-avian vertebrates are usually incidental hosts, but evidence is accumulating that this might not always be the case. Historically, WNV has been associated with asymptomatic infections and sporadic disease outbreaks in humans and horses in Africa, Europe, Asia and Australia. However, since 1994, the virus has caused frequent outbreaks of severe neuroinvasive disease in humans and horses in Europe and the Mediterranean Basin. In 1999, WNV underwent a dramatic expansion of its geographic range, and was reported for the first time in the Western Hemisphere during an outbreak of human and equine encephalitis in New York City. The outbreak was accompanied by extensive and unprecedented avian mortality. Since then, WNV has dispersed across the Western Hemisphere and is now found throughout the USA, Canada, Mexico and the Caribbean, and parts of Central and South America. WNV has been responsible for >27,000 human cases, >25,000 equine cases and hundreds of thousands of avian deaths in the USA but, surprisingly, there have been only sparse reports of WNV disease in vertebrates in the Caribbean and Latin America. This review summarizes our current understanding of WNV with particular emphasis on its transmission dynamics and changing epidemiology.

  2. 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.

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

    International Nuclear Information System (INIS)

    D’Arcy, Allan; Chaillet, Maxime; Schiering, Nikolaus; Villard, Frederic; Lim, Siew Pheng; Lefeuvre, Peggy; Erbel, Paul

    2006-01-01

    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

  4. 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.

  5. 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. ...

  6. West Nile virus equine serosurvey in the Czech and Slovak Republics

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk; Ludvíková, E.; Jahn, P.; Treml, F.; Rudolf, Ivo; Svobodová, Petra; Šikutová, Silvie; Betášová, Lenka; Bíreš, J.; Mojžíš, M.; Tinák, M.; Boldižár, M.; Citsoňová, G.; Staššíková, Z.

    2013-01-01

    Roč. 13, č. 10 (2013), s. 733-738 ISSN 1530-3667 Institutional support: RVO:68081766 Keywords : Flavivirus * Mosquito-borne virus * West Nile virus * Neutralizing antibodies * Horses Subject RIV: EE - Microbiology, Virology Impact factor: 2.531, year: 2013

  7. West Nile virus infection in cats : ABCD guidelines on prevention and management

    NARCIS (Netherlands)

    Egberink, Herman; Addie, Diane D; Boucraut-Baralon, Corine; Frymus, Tadeusz; Gruffydd-Jones, Tim; Hartmann, Katrin; Horzinek, Marian C; Hosie, Margaret J; Marsilio, Fulvio; Lloret, Albert; Lutz, Hans; Pennisi, Maria Grazia; Radford, Alan D; Thiry, Etienne; Truyen, Uwe; Möstl, Karin

    OVERVIEW: West Nile virus (WNV) is a zoonotic mosquito-borne virus with a broad host range that infects mainly birds and mosquitos, but also mammals (including humans), reptiles, amphibians and ticks. It is maintained in a bird-mosquito-bird transmission cycle. The most important vectors are

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

    International Nuclear Information System (INIS)

    Kaufmann, Bärbel; Plevka, Pavel; Kuhn, Richard J.; Rossmann, Michael G.

    2010-01-01

    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

  9. 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.

  10. Use of Temperature to Improve West Nile Virus Forecasts

    Science.gov (United States)

    Shaman, J. L.; DeFelice, N.; Schneider, Z.; Little, E.; Barker, C.; Caillouet, K.; Campbell, S.; Damian, D.; Irwin, P.; Jones, H.; Townsend, J.

    2017-12-01

    Ecological and laboratory studies have demonstrated that temperature modulates West Nile virus (WNV) transmission dynamics and spillover infection to humans. Here we explore whether the inclusion of temperature forcing in a model depicting WNV transmission improves WNV forecast accuracy relative to a baseline model depicting WNV transmission without temperature forcing. Both models are optimized using a data assimilation method and two observed data streams: mosquito infection rates and reported human WNV cases. Each coupled model-inference framework is then used to generate retrospective ensemble forecasts of WNV for 110 outbreak years from among 12 geographically diverse United States counties. The temperature-forced model improves forecast accuracy for much of the outbreak season. From the end of July until the beginning of October, a timespan during which 70% of human cases are reported, the temperature-forced model generated forecasts of the total number of human cases over the next 3 weeks, total number of human cases over the season, the week with the highest percentage of infectious mosquitoes, and the peak percentage of infectious mosquitoes that were on average 5%, 10%, 12%, and 6% more accurate, respectively, than the baseline model. These results indicate that use of temperature forcing improves WNV forecast accuracy and provide further evidence that temperatures influence rates of WNV transmission. The findings help build a foundation for implementation of a statistically rigorous system for real-time forecast of seasonal WNV outbreaks and their use as a quantitative decision support tool for public health officials and mosquito control programs.

  11. West Nile Virus in Mosquitoes of Iranian Wetlands.

    Science.gov (United States)

    Bagheri, Masoomeh; Terenius, Olle; Oshaghi, Mohammad Ali; Motazakker, Morteza; Asgari, Sassan; Dabiri, Farrokh; Vatandoost, Hassan; Mohammadi Bavani, Mulood; Chavshin, Ali Reza

    2015-12-01

    The West Nile virus (WNV) transmission cycle includes a wide range of migratory wetland birds as reservoirs, mosquitoes as biological vectors, and equines and humans as dead-end hosts. Despite the presence of potential vector species, there is no information about the existence of WNV in mosquito vectors in Iran. The Iranian West Azerbaijan Province is located in the northwestern part of Iran and has borders with Turkey, Iraq, Armenia, and the Republic of Azerbaijan. The current study was conducted to identify the wetland mosquitoes of the West Azerbaijan Province and their infection with WNV. In this study, 2143 specimens were collected, comprising 1541 adults and 602 larvae. Six species belonging to four genera were collected and identified: Anopheles maculipennis sensu lato (s.l.), Culex (Cx.) hortensis, Cx. pipiens s.l., Cx. theileri, Culiseta longiareolata, and Aedes (Ae.) (Ochlerotatus) caspius. In total, 45 pools of mosquitoes were examined. Two of the adult pools collected from the same location showed the presence of WNV in Ae. (Och.) caspius, from Sangar, Makoo County, as confirmed by PCR and sequencing. Due to the discovery of WNV in the mosquito population of the region, and the presence of wetlands and significant populations of migratory birds, the health sector should carefully monitor the factors involved in the cycle of this disease.

  12. Syndromic surveillance for West Nile virus using raptors in rehabilitation.

    Science.gov (United States)

    Ana, Alba; Perez Andrés, M; Julia, Ponder; Pedro, Puig; Arno, Wünschmann; Kimberly, Vander Waal; Julio, Alvarez; Michelle, Willette

    2017-11-29

    Wildlife rehabilitation centers routinely gather health-related data from diverse species. Their capability to signal the occurrence of emerging pathogens and improve traditional surveillance remains largely unexplored. This paper assessed the utility for syndromic surveillance of raptors admitted to The Raptor Center (TRC) to signal circulation of West Nile Virus (WNV) in Minnesota between 1990 and 2014. An exhaustive descriptive analysis using grouping time series structures and models of interrupted times series was conducted for indicator subsets. A total of 13,080 raptors were monitored. The most representative species were red-tailed hawks, great horned owls, Cooper's hawks, American kestrels and bald eagles. Results indicated that temporal patterns of accessions at the TRC changed distinctively after the incursion of WNV in 2002. The frequency of hawks showing WNV-like signs increased almost 3 times during July and August, suggesting that monitoring of hawks admitted to TRC with WNV-like signs could serve as an indicator of WNV circulation. These findings were also supported by the results of laboratory diagnosis. This study demonstrates that monitoring of data routinely collected by wildlife rehabilitation centers has the potential to signal the spread of pathogens that may affect wild, domestic animals and humans, thus supporting the early detection of disease incursions in a region and monitoring of disease trends. Ultimately, data collected in rehabilitation centers may provide insights to efficiently allocate financial and human resources on disease prevention and surveillance.

  13. West Nile Virus Encephalitis in a Patient with Neuroendocrine Carcinoma

    Directory of Open Access Journals (Sweden)

    Romina Deldar

    2016-01-01

    Full Text Available Importance. Oftentimes, when patients with metastatic cancer present with acute encephalopathy, it is suspected to be secondary to their underlying malignancy. However, there are multiple causes of delirium such as central nervous system (CNS infections, electrolyte abnormalities, and drug adverse reactions. Because West Nile Virus (WNV neuroinvasive disease has a high mortality rate in immunosuppressed patients, a high index of suspicion is required in patients who present with fever, altered mental status, and other neurological symptoms. Observations. Our case report details a single patient with brain metastases who presented with unexplained fever, encephalopathy, and new-onset tremors. Initially, it was assumed that his symptoms were due to his underlying malignancy or seizures. However, because his unexplained fevers persisted, lumbar puncture was pursued. Cerebrospinal fluid analysis included WNV polymerase chain reaction and serologies were ordered which eventually led to diagnosis of WNV encephalitis. Conclusions and Relevance. Patients with metastatic cancer who present with encephalopathy are often evaluated with assumption that malignancy is the underlying etiology. This can lead to delays in diagnosis and possible mistreatment. Our case highlights the importance of maintaining a broad differential diagnosis and an important diagnostic consideration of WNV encephalitis in patients with cancer.

  14. Immunogenicity and protective efficacy of recombinant Modified Vaccinia virus Ankara candidate vaccines delivering West Nile virus envelope antigens

    NARCIS (Netherlands)

    Volz, Asisa; Lim, Stephanie; Kaserer, Martina; Pijlman, Gorben P.

    2016-01-01

    West Nile virus (WNV) cycles between insects and wild birds, and is transmitted via mosquito vectors to horses and humans, potentially causing severe neuroinvasive disease. Modified Vaccinia virus Ankara (MVA) is an advanced viral vector for developing new recombinant vaccines against infectious

  15. Wild Birds in Romania Are More Exposed to West Nile Virus Than to Newcastle Disease Virus.

    Science.gov (United States)

    Paştiu, Anamaria Ioana; Pap, Péter László; Vágási, Csongor István; Niculae, Mihaela; Páll, Emőke; Domşa, Cristian; Brudaşcă, Florinel Ghe; Spînu, Marina

    2016-03-01

    The aim of this study was to evaluate the seroprevalence of West Nile virus (WNV) and Newcastle disease virus (NDV) in wild and domestic birds from Romania. During 2011-2014, 159 plasma samples from wild birds assigned to 11 orders, 27 families, and 61 species and from 21 domestic birds (Gallus gallus domesticus, Anas platyrhynchos domesticus) were collected. The sera were assayed by two commercial competitive enzyme-linked immunosorbent assay (cELISA) kits for antibodies against WNV and NDV. We found a high prevalence of WNV antibodies in both domestic (19.1%) and wild (32.1%) birds captured after the human epidemic in 2010. Moreover, the presence of anti-NDV antibodies among wild birds from Romania (5.4%) was confirmed serologically for the first time, as far as we are aware. Our findings provide evidence that wild birds, especially resident ones are involved in local West Nile and Newcastle disease enzootic and epizootic cycles. These may allow virus maintenance and spread and also enhance the chance of new outbreaks.

  16. Analysis of YouTube as a source of information for West Nile Virus infection.

    Science.gov (United States)

    Dubey, Divyanshu; Amritphale, Amod; Sawhney, Anshudha; Dubey, Devashish; Srivastav, Nupur

    2014-12-01

    A major outbreak of West Nile Virus was seen last year in different parts of the United States. Adequate dissemination of correct information about the disease would have helped decrease its spread and the associated panic in the general population. In this study, we looked into the use of YouTube as a resource for providing information about West Nile Virus infection. This study aims to identify and evaluate YouTube as resource for providing information on West Nile Virus infection to the general public. YouTube was searched on November 25, 2012, using the keywords West Nile Virus epidemic, West Nile Virus infection, and West Nile Virus prevention for videos uploaded in the past 6 months containing relevant information about the disease. The videos were classified as useful, misleading, or as news updates based on the type of information contained. Total viewership, number of days since upload, total duration of videos, and source of upload were noted. A total of 106 videos with information on West Nile Virus infection were included in the study, with 79.24% having useful information about the disease. Among the useful videos, 51/84 (60.71%) had information on disease prevention, and 29/84 (34.52%) contained information on news and research updates. The majority of these videos were uploaded by individuals (54.6%) or news agencies (41.8 %). Healthcare agencies contributed only 3.4 % of the total videos. Even though the useful videos represented 72% of all videos, there was significantly higher total viewership and viewership per day for the non-useful videos (PYouTube may be a significant resource for dissemination of information on public health issues like West Nile virus infection and should be targeted by healthcare agencies for this use. The major drawback of this medium is lack of verification by authorized healthcare professionals before these videos are made available for viewing by the community. Hence, a strict caution should be exercised in obtaining

  17. Use of temperature to improve West Nile virus forecasts.

    Directory of Open Access Journals (Sweden)

    Nicholas B DeFelice

    2018-03-01

    Full Text Available Ecological and laboratory studies have demonstrated that temperature modulates West Nile virus (WNV transmission dynamics and spillover infection to humans. Here we explore whether inclusion of temperature forcing in a model depicting WNV transmission improves WNV forecast accuracy relative to a baseline model depicting WNV transmission without temperature forcing. Both models are optimized using a data assimilation method and two observed data streams: mosquito infection rates and reported human WNV cases. Each coupled model-inference framework is then used to generate retrospective ensemble forecasts of WNV for 110 outbreak years from among 12 geographically diverse United States counties. The temperature-forced model improves forecast accuracy for much of the outbreak season. From the end of July until the beginning of October, a timespan during which 70% of human cases are reported, the temperature-forced model generated forecasts of the total number of human cases over the next 3 weeks, total number of human cases over the season, the week with the highest percentage of infectious mosquitoes, and the peak percentage of infectious mosquitoes that on average increased absolute forecast accuracy 5%, 10%, 12%, and 6%, respectively, over the non-temperature forced baseline model. These results indicate that use of temperature forcing improves WNV forecast accuracy and provide further evidence that temperature influences rates of WNV transmission. The findings provide a foundation for implementation of a statistically rigorous system for real-time forecast of seasonal WNV outbreaks and their use as a quantitative decision support tool for public health officials and mosquito control programs.

  18. Complete genome sequence of jacquemontia yellow vein virus, a novel begomovirus infecting Jacquemontia tamnifolia in Venezuela.

    Science.gov (United States)

    Fiallo-Olivé, Elvira; Chirinos, Dorys T; Geraud-Pouey, Francis; Navas-Castillo, Jesús

    2017-08-01

    Wild plants of the family Convolvulaceae are hosts for a few New World begomoviruses (genus Begomovirus, family Geminiviridae). In this work, we report the complete genome sequence of a new begomovirus infecting the wild convolvulaceous plant Jacquemontia tamnifolia in Venezuela. The cloned bipartite genome showed the organization of typical New World begomoviruses and was found to be phylogenetically related to those of begomoviruses from Venezuela and other Caribbean countries. Several recombination events have been shown to have occurred involving genome fragment exchange with related begomoviruses infecting crops such as tomato and cucurbits and wild plants, including Jacquemontia sp. We propose the name jacquemontia yellow vein virus (JacYVV) for this new begomovirus.

  19. West Nile Virus and Usutu Virus Monitoring of Wild Birds in Germany

    Science.gov (United States)

    Michel, Friederike; Fast, Christine; Reuschel, Maximilian; Müller, Kerstin; Urbaniak, Sylvia; Brandes, Florian; Schwehn, Rebekka; Groschup, Martin H.; Ziegler, Ute

    2018-01-01

    By systematically setting up a unique nation-wide wild bird surveillance network, we monitored migratory and resident birds for zoonotic arthropod-borne virus infections, such as the flaviviruses West Nile virus (WNV) and Usutu virus (USUV). More than 1900 wild bird blood samples, from 20 orders and 136 different bird species, were collected between 2014 and 2016. Samples were investigated by WNV and USUV-specific real-time polymerase chain reactions as well as by differentiating virus neutralization tests. Dead bird surveillance data, obtained from organ investigations in 2016, were also included. WNV-specific RNA was not detected, whereas four wild bird blood samples tested positive for USUV-specific RNA. Additionally, 73 USUV-positive birds were detected in the 2016 dead bird surveillance. WNV neutralizing antibodies were predominantly found in long-distance, partial and short-distance migrants, while USUV neutralizing antibodies were mainly detected in resident wild bird species, preferentially with low seroprevalences. To date, WNV-specific RNA has neither been detected in wild birds, nor in mosquitoes, thus, we conclude that WNV is not yet present in Germany. Continued wild bird and mosquito monitoring studies are essential to detect the incursion of zoonotic viruses and to allow risk assessments for zoonotic pathogens. PMID:29361762

  20. 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.

    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

  1. Importance of bird-to-bird transmission for the establishment of West Nile Virus

    NARCIS (Netherlands)

    Hartemink, N.A.; Davis, S.A.; Reiter, P.; Hubálek, Z.; Heesterbeek, J.A.P.

    2007-01-01

    West Nile virus (WNV) is principally considered to be maintained in a mosquito–bird transmission cycle. Under experimental conditions, several other transmission routes have been observed, but the significance of these additional routes in nature is unknown. Here, we derive an expression for the

  2. Detecting West Nile virus in owls and raptors by an antigen-capture assay.

    Science.gov (United States)

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

    2004-12-01

    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 raptors.

  3. Can reconstructed land surface temperature data from space predict a West Nile Virus outbreak?

    NARCIS (Netherlands)

    Andreo, V.; Metz, J.C.M.; Neteler, M.; Rosà, R.; Marcantonio, M.; Billinis, C.; Rizzoli, A.; Papa, Anne-Laure

    2017-01-01

    Temperature is one of the main drivers of ecological processes. The availability of temporally and spatially continuous temperature time series is crucial in different research and application fields, such as epidemiology and control of zoonotic diseases. In 2010, several West Nile virus (WNV)

  4. Screening for West Nile virus infections of susceptible animal species in Austria

    Czech Academy of Sciences Publication Activity Database

    Weissenböck, H.; Hubálek, Zdeněk; Halouzka, Jiří; Pichlmair, A.; Maderner, A.; Fragner, K.; Kolodziejek, J.; Loupal, G.; Kölbl, S.; Nowotny, N.

    2003-01-01

    Roč. 131, c. 2 (2003), s. 1023-1027 ISSN 0950-2688 Grant - others:Hochschuljubiläumsstiftung der Stadt Wien(AT) - Institutional research plan: CEZ:AV0Z6093917 Keywords : West Nile virus Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 1.509, year: 2003

  5. West Nile Virus positive blood donation and subsequent entomological investigation, Austria, 2014

    Czech Academy of Sciences Publication Activity Database

    Kolodziejek, J.; Seidel, B.; Jungbauer, C.; Dimmel, K.; Kolodziejek, M.; Rudolf, Ivo; Hubálek, Zdeněk; Allerberger, F.; Nowotny, N.

    2015-01-01

    Roč. 10, č. 5 (2015), e0126381 E-ISSN 1932-6203 EU Projects: European Commission(XE) 261504 - EDENEXT Institutional support: RVO:68081766 Keywords : West Nile virus * Austria Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 3.057, year: 2015

  6. Drought and immunity determine the intensity of West Nile virus epidemics and climate change impacts.

    Science.gov (United States)

    Paull, Sara H; Horton, Daniel E; Ashfaq, Moetasim; Rastogi, Deeksha; Kramer, Laura D; Diffenbaugh, Noah S; Kilpatrick, A Marm

    2017-02-08

    The effect of global climate change on infectious disease remains hotly debated because multiple extrinsic and intrinsic drivers interact to influence transmission dynamics in nonlinear ways. The dominant drivers of widespread pathogens, like West Nile virus, can be challenging to identify due to regional variability in vector and host ecology, with past studies producing disparate findings. Here, we used analyses at national and state scales to examine a suite of climatic and intrinsic drivers of continental-scale West Nile virus epidemics, including an empirically derived mechanistic relationship between temperature and transmission potential that accounts for spatial variability in vectors. We found that drought was the primary climatic driver of increased West Nile virus epidemics, rather than within-season or winter temperatures, or precipitation independently. Local-scale data from one region suggested drought increased epidemics via changes in mosquito infection prevalence rather than mosquito abundance. In addition, human acquired immunity following regional epidemics limited subsequent transmission in many states. We show that over the next 30 years, increased drought severity from climate change could triple West Nile virus cases, but only in regions with low human immunity. These results illustrate how changes in drought severity can alter the transmission dynamics of vector-borne diseases. © 2017 The Author(s).

  7. Ovicidal and larvicidal effects of garlic and asafoetida essential oils against West Nile virus vectors

    Science.gov (United States)

    We examined the chemical composition of garlic and asafoetida essential oils and their individual and combined toxicity against larvae of two West Nile virus vectors, Culex pipiens pipiens and Cx. restuans. The effect of the two essential oils on egg hatch was also examined. Ten and twelve compounds...

  8. West Nile Virus Outbreak in Houston and Harris County, Texas, USA, 2014.

    Science.gov (United States)

    Martinez, Diana; Murray, Kristy O; Reyna, Martin; Arafat, Raouf R; Gorena, Roberto; Shah, Umair A; Debboun, Mustapha

    2017-08-01

    Since 2002, West Nile virus (WNV) has been detected every year in Houston and the surrounding Harris County, Texas. In 2014, the largest WNV outbreak to date occurred, comprising 139 cases and causing 2 deaths. Additionally, 1,286 WNV-positive mosquito pools were confirmed, the most reported in a single mosquito season.

  9. West nile virus anti-body surveillance in three Sierra Nevada raptors of conservation concern

    Science.gov (United States)

    J.M. Hull; J.J. Keane; L.A. Tell; H.B. Ernest

    2010-01-01

    West Nile virus (WNV) infection has caused high levels of mortality in North American hawks and owls. To investigate the extent of infection among raptors of conservation concern in the Sierra Nevada, we tested 62 Northern Goshawks (Accipiter gentilis), 209 Spotted Owls (Strix occidentalis), and 22 Great Gray Owls (...

  10. Surveillance for West Nile virus in clinic-admitted raptors, Colorado.

    Science.gov (United States)

    Nemeth, Nicole; Kratz, Gail; Edwards, Eric; Scherpelz, Judy; Bowen, Richard; Komar, Nicholas

    2007-02-01

    In 2005, 13.5% of clinic-admitted raptors in northern Colorado tested positive for West Nile virus (WNV). Clinic-admitted-raptor surveillance detected WNV activity nearly 14 weeks earlier than other surveillance systems. WNV surveillance using live raptor admissions to rehabilitation clinics may offer a novel surveillance method and should be considered along with other techniques already in use.

  11. 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

  12. Comparison of assays for the detection of West Nile virus antibodies in chicken serum

    Czech Academy of Sciences Publication Activity Database

    Weingartl, H. M.; Drebot, M. A.; Hubálek, Zdeněk; Halouzka, Jiří; Andonova, M.; Dibernardo, A.; Cottam-Birt, C.; Larence, J.; Marszal, P.

    2003-01-01

    Roč. 67, č. 2 (2003), s. 128-132 ISSN 0830-9000 Institutional research plan: CEZ:AV0Z6093917 Keywords : West Nile virus Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.101, year: 2003 http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=227040&blobtype=pdf

  13. 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.

  14. Serologic survey of potential vertebrate hosts for West Nile Virus in Poland

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk; Wegner, E.; Halouzka, Jiří; Tryjanowski, P.; Jerzak, L.; Šikutová, Silvie; Rudolf, Ivo; Kruszewicz, A. G.; Jaworski, Z.; Włodarczyk, R.

    2008-01-01

    Roč. 21, č. 2 (2008), s. 247-254 ISSN 0882-8245 R&D Projects: GA AV ČR IAA600930611 EU Projects: European Commission(XE) 10284 - EDEN Institutional research plan: CEZ:AV0Z60930519 Source of funding: R - rámcový projekt EK Keywords : antibodies – West Nile virus – Usutu virus – Flavivirus * Poland * birds * horses Subject RIV: EE - Microbiology, Virology Impact factor: 1.949, year: 2008

  15. Evolutionary and Ecological Characterization of Mayaro Virus Strains Isolated during an Outbreak, Venezuela, 2010.

    Science.gov (United States)

    Auguste, Albert J; Liria, Jonathan; Forrester, Naomi L; Giambalvo, Dileyvic; Moncada, Maria; Long, Kanya C; Morón, Dulce; de Manzione, Nuris; Tesh, Robert B; Halsey, Eric S; Kochel, Tadeusz J; Hernandez, Rosa; Navarro, Juan-Carlos; Weaver, Scott C

    2015-10-01

    In 2010, an outbreak of febrile illness with arthralgic manifestations was detected at La Estación village, Portuguesa State, Venezuela. The etiologic agent was determined to be Mayaro virus (MAYV), a reemerging South American alphavirus. A total of 77 cases was reported and 19 were confirmed as seropositive. MAYV was isolated from acute-phase serum samples from 6 symptomatic patients. We sequenced 27 complete genomes representing the full spectrum of MAYV genetic diversity, which facilitated detection of a new genotype, designated N. Phylogenetic analysis of genomic sequences indicated that etiologic strains from Venezuela belong to genotype D. Results indicate that MAYV is highly conserved genetically, showing ≈17% nucleotide divergence across all 3 genotypes and 4% among genotype D strains in the most variable genes. Coalescent analyses suggested genotypes D and L diverged ≈150 years ago and genotype diverged N ≈250 years ago. This virus commonly infects persons residing near enzootic transmission foci because of anthropogenic incursions.

  16. A recombinant influenza A virus expressing domain III of West Nile virus induces protective immune responses against influenza and West Nile virus.

    Science.gov (United States)

    Martina, Byron E E; van den Doel, Petra; Koraka, Penelope; van Amerongen, Geert; Spohn, Gunther; Haagmans, Bart L; Provacia, Lisette B V; Osterhaus, Albert D M E; Rimmelzwaan, Guus F

    2011-04-26

    West Nile virus (WNV) continues to circulate in the USA and forms a threat to the rest of the Western hemisphere. Since methods for the treatment of WNV infections are not available, there is a need for the development of safe and effective vaccines. Here, we describe the construction of a recombinant influenza virus expressing domain III of the WNV glycoprotein E (Flu-NA-DIII) and its evaluation as a WNV vaccine candidate in a mouse model. FLU-NA-DIII-vaccinated mice were protected from severe body weight loss and mortality caused by WNV infection, whereas control mice succumbed to the infection. In addition, it was shown that one subcutaneous immunization with 10(5) TCID(50) Flu-NA-DIII provided 100% protection against challenge. Adoptive transfer experiments demonstrated that protection was mediated by antibodies and CD4+T cells. Furthermore, mice vaccinated with FLU-NA-DIII developed protective influenza virus-specific antibody titers. It was concluded that this vector system might be an attractive platform for the development of bivalent WNV-influenza vaccines.

  17. A recombinant influenza A virus expressing domain III of West Nile virus induces protective immune responses against influenza and West Nile virus.

    Directory of Open Access Journals (Sweden)

    Byron E E Martina

    Full Text Available West Nile virus (WNV continues to circulate in the USA and forms a threat to the rest of the Western hemisphere. Since methods for the treatment of WNV infections are not available, there is a need for the development of safe and effective vaccines. Here, we describe the construction of a recombinant influenza virus expressing domain III of the WNV glycoprotein E (Flu-NA-DIII and its evaluation as a WNV vaccine candidate in a mouse model. FLU-NA-DIII-vaccinated mice were protected from severe body weight loss and mortality caused by WNV infection, whereas control mice succumbed to the infection. In addition, it was shown that one subcutaneous immunization with 10(5 TCID(50 Flu-NA-DIII provided 100% protection against challenge. Adoptive transfer experiments demonstrated that protection was mediated by antibodies and CD4+T cells. Furthermore, mice vaccinated with FLU-NA-DIII developed protective influenza virus-specific antibody titers. It was concluded that this vector system might be an attractive platform for the development of bivalent WNV-influenza vaccines.

  18. Zika virus infection confers protection against West Nile virus challenge in mice.

    Science.gov (United States)

    Vázquez-Calvo, Ángela; Blázquez, Ana-Belén; Escribano-Romero, Estela; Merino-Ramos, Teresa; Saiz, Juan-Carlos; Martín-Acebes, Miguel A; Jiménez de Oya, Nereida

    2017-09-20

    Flaviviruses are RNA viruses that constitute a worrisome threat to global human and animal health. Zika virus (ZIKV), which was initially reported to cause a mild disease, recently spread in the Americas, infecting millions of people. During this recent epidemic, ZIKV infection has been linked to serious neurological diseases and birth defects, specifically Guillain-Barrè syndrome (GBS) and microcephaly. Because information about ZIKV immunity remains scarce, we assessed the humoral response of immunocompetent mice to infection with three viral strains of diverse geographical origin (Africa, Asia and America). No infected animals showed any sign of disease or died after infection. However, specific neutralizing antibodies were elicited in all infected mice. Considering the rapid expansion of ZIKV throughout the American continent and its co-circulation with other medically relevant flaviviruses, such as West Nile virus (WNV), the induction of protective immunity between ZIKV and WNV was analyzed. Remarkably, protection after challenge with WNV was observed in mice previously infected with ZIKV, as survival rates were significantly higher than in control mice. Moreover, previous ZIKV infection enhanced the humoral immune response against WNV. These findings may be relevant in geographical areas where both ZIKV and WNV co-circulate, as well as for the future development of broad-spectrum flavivirus vaccines.

  19. 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.

  20. The outbreak of West Nile virus infection in the New York City area in 1999.

    Science.gov (United States)

    Nash, D; Mostashari, F; Fine, A; Miller, J; O'Leary, D; Murray, K; Huang, A; Rosenberg, A; Greenberg, A; Sherman, M; Wong, S; Layton, M

    2001-06-14

    In late August 1999, an unusual cluster of cases of meningoencephalitis associated with muscle weakness was reported to the New York City Department of Health. The initial epidemiologic and environmental investigations suggested an arboviral cause. Active surveillance was implemented to identify patients hospitalized with viral encephalitis and meningitis. Cerebrospinal fluid, serum, and tissue specimens from patients with suspected cases underwent serologic and viral testing for evidence of arboviral infection. Outbreak surveillance identified 59 patients who were hospitalized with West Nile virus infection in the New York City area during August and September of 1999. The median age of these patients was 71 years (range, 5 to 95). The overall attack rate of clinical West Nile virus infection was at least 6.5 cases per million population, and it increased sharply with age. Most of the patients (63 percent) had clinical signs of encephalitis; seven patients died (12 percent). Muscle weakness was documented in 27 percent of the patients and flaccid paralysis in 10 percent; in all of the latter, nerve conduction studies indicated an axonal polyneuropathy in 14 percent. An age of 75 years or older was an independent risk factor for death (relative risk adjusted for the presence or absence of diabetes mellitus, 8.5; 95 percent confidence interval, 1.2 to 59.1), as was the presence of diabetes mellitus (age-adjusted relative risk, 5.1; 95 percent confidence interval, 1.5 to 17.3). This outbreak of West Nile meningoencephalitis in the New York City metropolitan area represents the first time this virus has been detected in the Western Hemisphere. Given the subsequent rapid spread of the virus, physicians along the eastern seaboard of the United States should consider West Nile virus infection in the differential diagnosis of encephalitis and viral meningitis during the summer months, especially in older patients and in those with muscle weakness.

  1. Molecular characterization of hepatitis E virus in patients with acute hepatitis in Venezuela.

    Science.gov (United States)

    García, Cristina Gutiérrez; Sánchez, Doneyla; Villalba, Maria Caridad Montalvo; Pujol, Flor Helene; de Los Ángeles Rodríguez Lay, Licel; Pinto, Belquis; Chacón, Elsa Patricia; Guzmán, Maria Guadalupe

    2012-07-01

    Hepatitis E virus (HEV) causes a common infection in developing countries. HEV infection occurs as outbreaks, as sporadic clinical cases and as large epidemics in endemic areas. The objective of this study was to determine the presence of HEV infection in patients with clinical suspicion of hepatitis A virus (HAV) infection, referred to the Instituto Nacional de Higiene "Rafael Rangel" in Venezuela. Seventy-four sera were tested for anti-HAV and anti-HEV IgM antibodies. HEV-RNA was amplified from anti-HEV IgM positive sera using nested reverse transcription polymerase chain reaction for ORF1 (RNA dependent RNA polymerase region) and the amplicons sequenced for phylogenetic analysis. The frequency of anti-HEV IgM was 22/74 (30%) in the samples tested. Dual infection with HAV and HEV was found in 31% (12/39) of anti-HAV IgM positive patients. Viremia was detected in 3/22 (14%) of sera positive for anti-HEV IgM. Two HEV strains were classified as genotype 1 and one as genotype 3, which were closely related to Yam 67 (north of India) and US1 isolates from the USA, respectively. These findings suggest that HEV is an important cause of acute viral hepatitis in Venezuela as a single infection or co-infection with HAV, with high morbidity in children and young adults suggesting that this infection is endemic in Venezuela. Copyright © 2012 Wiley Periodicals, Inc.

  2. Experimental transmission of West Nile Virus and Rift Valley Fever Virus by Culex pipiens from Lebanon.

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    Renée Zakhia

    2018-01-01

    Full Text Available West Nile virus (WNV and Rift Valley fever virus (RVFV are two emerging arboviruses transmitted by Culex pipiens species that includes two biotypes: pipiens and molestus. In Lebanon, human cases caused by WNV and RVFV have never been reported. However, the introduction of these viruses in the country is likely to occur through the migratory birds and animal trades. In this study, we evaluated the ability of Cx. pipiens, a predominant mosquito species in urban and rural regions in Lebanon, to transmit WNV and RVFV. Culex egg rafts were collected in the West Bekaa district, east of Lebanon and adult females of Cx. pipiens were experimentally infected with WNV and RVFV Clone 13 strain at titers of 1.6×108 and 1.33×107 plaque forming units (PFU/mL, respectively. We estimated viral infection, dissemination and transmission at 3, 7, 14 and 19 days post infection (dpi. Results showed that infection was higher for WNV than for RVFV from 3 dpi to 19 dpi. Viral dissemination and transmission started from 3 dpi for WNV; and only from 19 dpi for RVFV. Moreover, Cx. pipiens were able to excrete in saliva a higher number of viral particles of WNV (1028 ± 405 PFU/saliva at 19 dpi than RVFV (42 PFU/saliva at 19 dpi. Cx. pipiens from Lebanon are efficient experimental vectors of WNV and to a lower extent, RVFV. These findings should stimulate local authorities to establish an active entomological surveillance in addition to animal surveys for both viruses in the country.

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

    Science.gov (United States)

    Dusek, Robert J.; Richardson, D.; Egstad, Kristina 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. 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.

  5. Persistence of Antibodies to West Nile Virus in Naturally Infected Rock Pigeons (Columba livia)

    Science.gov (United States)

    Gibbs, Samantha E. J.; Hoffman, Douglas M.; Stark, Lillian M.; Marlenee, Nicole L.; Blitvich, Bradley J.; Beaty, Barry J.; Stallknecht, David E.

    2005-01-01

    Wild caught rock pigeons (Columba livia) with antibodies to West Nile virus were monitored for 15 months to determine antibody persistence and compare results of three serologic techniques. Antibodies persisted for the entire study as detected by epitope-blocking enzyme-linked immunosorbent assay and plaque reduction neutralization test. Maternal antibodies in squabs derived from seropositive birds persisted for an average of 27 days. PMID:15879030

  6. SEROLOGIC EVIDENCE OF WEST NILE VIRUS INFECTION IN BIRDS, TAMAULIPAS STATE, MEXICO

    OpenAIRE

    beaty, barry; FERNANDEZ, ILDEFONSO; contreras, juan francisco; blitvich, bradley; gonzalez, jose ignacio; cavazos, amanda a; loroño, maria alba; gluber, duante j.; Cropp, bruce; Calisher , Charles

    2003-01-01

    Following the introduction of West Nile virus (WNV) into North America in 1999, surveillance for WNV in migratory and resident birds was established in Tamaulipas State, northern Mexico in December 2001. Overall, 796 birds representing 70 species and 10 orders were captured and assayed for antibodies to WNV. Nine birds had flavivirus-specific antibodies by epitope-blocking enzyme-linked immunosorbent assay; four were confirmed to have antibody to WNV by plaque reduction neutralization test. T...

  7. Importance of bird-to-bird transmission for the establishment of West Nile virus

    Czech Academy of Sciences Publication Activity Database

    Hartemink, N. A.; Davis, S. A.; Reiter, P.; Hubálek, Zdeněk; Heesterbeek, J. A. P.

    2007-01-01

    Roč. 7, č. 4 (2007), s. 575-584 ISSN 1530-3667 EU Projects: European Commission(XE) 10284 - EDEN Institutional research plan: CEZ:AV0Z60930519 Source of funding: R - rámcový projekt EK Keywords : West Nile virus * basic reproduction number * direct transmission Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.919, year: 2007

  8. The Importance of Haematological and Biochemical Findings in Patients with West Nile Virus Neuroinvasive Disease

    Directory of Open Access Journals (Sweden)

    Urošević Aleksandar

    2016-10-01

    Full Text Available Background: West Nile virus neuroinvasive disease (WNND occurs in less than 1% of infected people. Leukocytosis with lymphocytopenia, mild anaemia, thrombocytopenia, elevated liver and muscle enzymes and hyponatremia are occasionally present in patients with WNND. Cerebrospinal fluid (CSF findings resemble other viral neuroinfections. The purpose of this study is to present some of the most important laboratory findings of our patients with WNND and to evaluate their correlation with fatal outcome.

  9. Second International Diagnostic Accuracy Study for the Serological Detection of West Nile Virus Infection

    OpenAIRE

    Sanchini, Andrea; Donoso-Mantke, Oliver; Papa, Anna; Sambri, Vittorio; Teichmann, Anette; Niedrig, Matthias

    2013-01-01

    Background: In recent decades, sporadic cases and outbreaks in humans of West Nile virus (WNV) infection have increased. Serological diagnosis of WNV infection can be performed by enzyme-linked immunosorbent assay (ELISA), immunofluorescence assay (IFA) neutralization test (NT) and by hemagglutination-inhibition assay. The aim of this study is to collect updated information regarding the performance accuracy of WNV serological diagnostics. Methodology/Principal findings: In 2011, the E...

  10. Occurrence of west nile virus infection in raptors at the Salton Sea, California.

    Science.gov (United States)

    Dusek, Robert J; Iko, William M; Hofmeister, Erik K

    2010-07-01

    We investigated the prevalence of West Nile virus (WNV)-neutralizing antibodies and infectious virus, and the occurrence of overwinter transmission in two raptor species during January and March 2006 at the Salton Sea, Imperial County, California. We captured 208 American Kestrels (Falco sparverius) (January, n=100; March, n=108) and 116 Burrowing Owls (Athene cunicularia) (January, n=52; March, n=64). Laboratory analysis revealed that 83% of American Kestrels and 31% of Burrowing Owls were positive for WNV-neutralizing antibodies. Additionally, two seroconversions were detected in Burrowing Owls between January and March. Infectious WNV, consistent with acute infection, was not detected in any bird.

  11. A rapid and quantitative assay for measuring antibody-mediated neutralization of West Nile virus infection

    International Nuclear Information System (INIS)

    Pierson, Theodore C.; Sanchez, Melissa D.; Puffer, Bridget A.; Ahmed, Asim A.; Geiss, Brian J.; Valentine, Laura E.; Altamura, Louis A.; Diamond, Michael S.; Doms, Robert W.

    2006-01-01

    West Nile virus (WNV) is a neurotropic flavivirus within the Japanese encephalitis antigenic complex that is responsible for causing West Nile encephalitis in humans. The surface of WNV virions is covered by a highly ordered icosahedral array of envelope proteins that is responsible for mediating attachment and fusion with target cells. These envelope proteins are also primary targets for the generation of neutralizing antibodies in vivo. In this study, we describe a novel approach for measuring antibody-mediated neutralization of WNV infection using virus-like particles that measure infection as a function of reporter gene expression. These reporter virus particles (RVPs) are produced by complementation of a sub-genomic replicon with WNV structural proteins provided in trans using conventional DNA expression vectors. The precision and accuracy of this approach stem from an ability to measure the outcome of the interaction between antibody and viral antigens under conditions that satisfy the assumptions of the law of mass action as applied to virus neutralization. In addition to its quantitative strengths, this approach allows the production of WNV RVPs bearing the prM-E proteins of different WNV strains and mutants, offering considerable flexibility for the study of the humoral immune response to WNV in vitro. WNV RVPs are capable of only a single round of infection, can be used under BSL-2 conditions, and offer a rapid and quantitative approach for detecting virus entry and its inhibition by neutralizing antibody

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

    Science.gov (United States)

    Lim, Pei-Yin; Keating, Julie A; Hoover, Spencer; Striker, Rob; Bernard, Kristen A

    2011-01-01

    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.

  13. 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.

  14. Evolution of Dengue Virus Type 3 Genotype III in Venezuela: Diversification, Rates and Population Dynamics

    Science.gov (United States)

    2010-01-01

    Background Dengue virus (DENV) is a member of the genus Flavivirus of the family Flaviviridae. DENV are comprised of four distinct serotypes (DENV-1 through DENV-4) and each serotype can be divided in different genotypes. Currently, there is a dramatic emergence of DENV-3 genotype III in Latin America. Nevertheless, we still have an incomplete understanding of the evolutionary forces underlying the evolution of this genotype in this region of the world. In order to gain insight into the degree of genetic variability, rates and patterns of evolution of this genotype in Venezuela and the South American region, phylogenetic analysis, based on a large number (n = 119) of envelope gene sequences from DENV-3 genotype III strains isolated in Venezuela from 2001 to 2008, were performed. Results Phylogenetic analysis revealed an in situ evolution of DENV-3 genotype III following its introduction in the Latin American region, where three different genetic clusters (A to C) can be observed among the DENV-3 genotype III strains circulating in this region. Bayesian coalescent inference analyses revealed an evolutionary rate of 8.48 × 10-4 substitutions/site/year (s/s/y) for strains of cluster A, composed entirely of strains isolated in Venezuela. Amino acid substitution at position 329 of domain III of the E protein (A→V) was found in almost all E proteins from Cluster A strains. Conclusions A significant evolutionary change between DENV-3 genotype III strains that circulated in the initial years of the introduction in the continent and strains isolated in the Latin American region in recent years was observed. The presence of DENV-3 genotype III strains belonging to different clusters was observed in Venezuela, revealing several introduction events into this country. The evolutionary rate found for Cluster A strains circulating in Venezuela is similar to the others previously established for this genotype in other regions of the world. This suggests a lack of correlation

  15. Evolution of Dengue Virus Type 3 Genotype III in Venezuela: Diversification, Rates and Population Dynamics

    Directory of Open Access Journals (Sweden)

    Moratorio Gonzalo

    2010-11-01

    Full Text Available Abstract Background Dengue virus (DENV is a member of the genus Flavivirus of the family Flaviviridae. DENV are comprised of four distinct serotypes (DENV-1 through DENV-4 and each serotype can be divided in different genotypes. Currently, there is a dramatic emergence of DENV-3 genotype III in Latin America. Nevertheless, we still have an incomplete understanding of the evolutionary forces underlying the evolution of this genotype in this region of the world. In order to gain insight into the degree of genetic variability, rates and patterns of evolution of this genotype in Venezuela and the South American region, phylogenetic analysis, based on a large number (n = 119 of envelope gene sequences from DENV-3 genotype III strains isolated in Venezuela from 2001 to 2008, were performed. Results Phylogenetic analysis revealed an in situ evolution of DENV-3 genotype III following its introduction in the Latin American region, where three different genetic clusters (A to C can be observed among the DENV-3 genotype III strains circulating in this region. Bayesian coalescent inference analyses revealed an evolutionary rate of 8.48 × 10-4 substitutions/site/year (s/s/y for strains of cluster A, composed entirely of strains isolated in Venezuela. Amino acid substitution at position 329 of domain III of the E protein (A→V was found in almost all E proteins from Cluster A strains. Conclusions A significant evolutionary change between DENV-3 genotype III strains that circulated in the initial years of the introduction in the continent and strains isolated in the Latin American region in recent years was observed. The presence of DENV-3 genotype III strains belonging to different clusters was observed in Venezuela, revealing several introduction events into this country. The evolutionary rate found for Cluster A strains circulating in Venezuela is similar to the others previously established for this genotype in other regions of the world. This suggests a

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

    Science.gov (United States)

    Olsen, Glenn H; Miller, Kimberli J; Docherty, Douglas E; Bochsler, Valerie S; Sileo, Louis

    2009-06-01

    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 cranes. Seven days postchallenge vaccinated cranes had significantly less cloacal shedding of the virus (P cranes and significantly less weight loss (P cranes. Vaccinated sandhill cranes developed significantly higher titers 14 days postchallenge and were viremic for shorter periods of time after challenge than unvaccinated individuals. Unvaccinated challenged cranes had glial cell aggregates in both the brain and brain stem areas, and this was not observed in vaccinated challenged cranes or in vaccinated unchallenged cranes.

  17. Environmental and biological factors influencing Culex pipiens quinquefasciatus (Diptera: Culicidae) vector competence for West Nile Virus.

    Science.gov (United States)

    Richards, Stephanie L; Lord, Cynthia C; Pesko, Kendra N; Tabachnick, Walter J

    2010-07-01

    Interactions between environmental and biological factors affect the vector competence of Culex pipiens quinquefasciatus for West Nile virus. Three age cohorts from two Cx. p. quinquefasciatus colonies were fed blood containing a low- or high-virus dose, and each group was held at two different extrinsic incubation temperatures (EIT) for 13 days. The colonies differed in the way that they responded to the effects of the environment on vector competence. The effects of mosquito age on aspects of vector competence were dependent on the EIT and dose, and they changed depending on the colony. Complex interactions must be considered in laboratory studies of vector competence, because the extent of the genetic and environmental variation controlling vector competence in nature is largely unknown. Differences in the environmental (EIT and dose) and biological (mosquito age and colony) effects from previous studies of Cx. p. quinquefasciatus vector competence for St. Louis encephalitis virus are discussed.

  18. Equine Immunoglobulin and Equine Neutralizing F(ab')₂ Protect Mice from West Nile Virus Infection.

    Science.gov (United States)

    Cui, Jiannan; Zhao, Yongkun; Wang, Hualei; Qiu, Boning; Cao, Zengguo; Li, Qian; Zhang, Yanbo; Yan, Feihu; Jin, Hongli; Wang, Tiecheng; Sun, Weiyang; Feng, Na; Gao, Yuwei; Sun, Jing; Wang, Yanqun; Perlman, Stanley; Zhao, Jincun; Yang, Songtao; Xia, Xianzhu

    2016-12-18

    West Nile virus (WNV) is prevalent in Africa, Europe, the Middle East, West Asia, and North America, and causes epidemic encephalitis. To date, no effective therapy for WNV infection has been developed; therefore, there is urgent need to find an efficient method to prevent WNV disease. In this study, we prepared and evaluated the protective efficacy of immune serum IgG and pepsin-digested F(ab')₂ fragments from horses immunized with the WNV virus-like particles (VLP) expressing the WNV M and E proteins. Immune equine F(ab')₂ fragments and immune horse sera efficiently neutralized WNV infection in tissue culture. The passive transfer of equine immune antibodies significantly accelerated the virus clearance in the spleens and brains of WNV infected mice, and reduced mortality. Thus, equine immunoglobulin or equine neutralizing F(ab')₂ passive immunotherapy is a potential strategy for the prophylactic or therapeutic treatment of patients infected with WNV.

  19. Equine Immunoglobulin and Equine Neutralizing F(ab′2 Protect Mice from West Nile Virus Infection

    Directory of Open Access Journals (Sweden)

    Jiannan Cui

    2016-12-01

    Full Text Available West Nile virus (WNV is prevalent in Africa, Europe, the Middle East, West Asia, and North America, and causes epidemic encephalitis. To date, no effective therapy for WNV infection has been developed; therefore, there is urgent need to find an efficient method to prevent WNV disease. In this study, we prepared and evaluated the protective efficacy of immune serum IgG and pepsin-digested F(ab′2 fragments from horses immunized with the WNV virus-like particles (VLP expressing the WNV M and E proteins. Immune equine F(ab′2 fragments and immune horse sera efficiently neutralized WNV infection in tissue culture. The passive transfer of equine immune antibodies significantly accelerated the virus clearance in the spleens and brains of WNV infected mice, and reduced mortality. Thus, equine immunoglobulin or equine neutralizing F(ab′2 passive immunotherapy is a potential strategy for the prophylactic or therapeutic treatment of patients infected with WNV.

  20. Role of communally nesting ardeid birds in the epidemiology of West Nile virus revisited.

    Science.gov (United States)

    Reisen, William K; Wheeler, Sarah; Armijos, M Veronica; Fang, Ying; Garcia, Sandra; Kelley, Kara; Wright, Stan

    2009-06-01

    Although herons and egrets in the family Ardeidae frequently have been associated with viruses in the Japanese encephalitis virus serocomplex, communal nesting colonies do not appear to be a focus of early season and rapid amplification of West Nile virus (WNV) in California. Evidence for repeated WNV infection was found by testing living and dead nestlings collected under trees with mixed species ardeid colonies nesting above in an oak grove near the University of California arboretum in Davis and in a Eucalyptus grove at a rural farmstead. However, mosquito infection rates at both nesting sites were low and positive pools did not occur earlier than at comparison sites within the City of Davis or at the Yolo Bypass wetlands managed for rice production and waterfowl habitat. Black-crowned night herons (Nycticorax nycticorax) were the most abundant and frequently infected ardeid species, indicating that WNV may be an important cause of mortality among nestlings of this species.

  1. Specific interaction of capsid protein and importin-α/β influences West Nile virus production

    International Nuclear Information System (INIS)

    Bhuvanakantham, Raghavan; Chong, Mun-Keat; Ng, Mah-Lee

    2009-01-01

    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-α. 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-α/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-α/C protein interaction in the context of flavivirus life-cycle.

  2. 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.

  3. West Nile virus circulation in South-Eastern Romania, 2011 to 2013.

    Science.gov (United States)

    Dinu, S; Cotar, A I; Pănculescu-Gătej, I R; Fălcuţă, E; Prioteasa, F L; Sîrbu, A; Oprişan, G; Bădescu, D; Reiter, P; Ceianu, C S

    2015-05-21

    Lineage 2 West Nile virus (WNV), previously found only in sub-Saharan Africa and Madagascar, was identified in Hungary in 2004 and has rapidly expanded in Europe in the past decade. Following a significant outbreak of West Nile fever with neurological cases caused by lineage 1 WNV in Romania in 1996, scattered cases have been recorded in the south-east of the country in each transmission season. Another outbreak, affecting a larger area and caused by lineage 2 WNV, was recorded in 2010. We analysed human sera from neuroinvasive West Nile fever cases and mosquitoes, sampled in south-eastern Romania between 2011 and 2013, for the presence of WNV genome, and obtained partial NS5 and envelope glycoprotein sequences. Human- and mosquito-derived WNV sequences were highly similar (99%) to Volgograd 2007 lineage 2 WNV and differed from isolates previously detected in central and southern Europe. WNV was detected in one pool of Culex pipiens s.l. males, documenting vertical transmission. Lineage 4 WNV, of unknown pathogenicity to mammals, was found in the amphibian-feeding mosquito Uranotaenia unguiculata from the Danube Delta. Our results present molecular evidence for the maintenance of the same isolates of Volgograd 2007-like lineage 2 WNV in south-eastern Romania between 2011 and 2013.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Dynamics of West Nile virus persistence in House Sparrows (Passer domesticus.

    Directory of Open Access Journals (Sweden)

    Sarah S Wheeler

    Full Text Available West Nile Virus (WNV is now endemic throughout North America, with annual recurrence dependent upon successful overwintering when cold temperatures drive mosquito vectors into inactivity and halt transmission. To investigate whether avian hosts may serve as an overwintering mechanism, groups of eight to ten House Sparrows were experimentally infected with a WN02 genotype of WNV and then held until necropsy at 3, 5, 7, 9, 12, 15, or 18 weeks post-infection (pi when they were assessed for the presence of persistent infection. Blood was collected from all remaining birds every two weeks pi, and sera tested for WNV RNA and WNV neutralizing antibodies. West Nile virus RNA was present in the sera of some birds up to 7 weeks pi and all birds retained neutralizing antibodies throughout the experiment. The detection of persistently infected birds decreased with time, from 100% (n = 13 positive at 3 weeks post-infection (pi to 12.5% (n = 8 at 18 weeks pi. Infectious virus was isolated from the spleens of birds necropsied at 3, 5, 7 and 12 weeks pi. The current study confirmed previous reports of infectious WNV persistence in avian hosts, and further characterized the temporal nature of these infections. Although these persistent infections supported the hypothesis that infected birds may serve as an overwintering mechanism, mosquito-infectious recrudescent viremias have yet to be demonstrated thereby providing proof of principle.

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

    Directory of Open Access Journals (Sweden)

    June H. Williams

    2014-09-01

    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.

  7. Identifying environmental risk factors and mapping the risk of human West Nile virus in South Dakota.

    Science.gov (United States)

    Hess, A.; Davis, J. K.; Wimberly, M. C.

    2017-12-01

    Human West Nile virus (WNV) first arrived in the USA in 1999 and has since then spread across the country. Today, the highest incidence rates are found in the state of South Dakota. The disease occurrence depends on the complex interaction between the mosquito vector, the bird host and the dead-end human host. Understanding the spatial domain of this interaction and being able to identify disease transmission hotspots is crucial for effective disease prevention and mosquito control. In this study we use geospatial environmental information to understand what drives the spatial distribution of cases of human West Nile virus in South Dakota and to map relative infection risk across the state. To map the risk of human West Nile virus in South Dakota, we used geocoded human case data from the years 2004-2016. Satellite data from the Landsat ETM+ and MODIS for the years 2003 to 2016 were used to characterize environmental patterns. From these datasets we calculated indices, such as the normalized differenced vegetation index (NDVI) and the normalized differenced water index (NDWI). In addition, datasets such as the National Land Data Assimilation System (NLDAS), National Land Cover Dataset (NLCD), National Wetland inventory (NWI), National Elevation Dataset (NED) and Soil Survey Geographic Database (SSURGO) were utilized. Environmental variables were summarized for a buffer zone around the case and control points. We used a boosted regression tree model to identify the most important variables describing the risk of WNV infection. We generated a risk map by applying this model across the entire state. We found that the highest relative risk is present in the James River valley in northeastern South Dakota. Factors that were identified as influencing the transmission risk include inter-annual variability of vegetation cover, water availability and temperature. Land covers such as grasslands, low developed areas and wetlands were also found to be good predictors for human

  8. Novel flavivirus or new lineage of West Nile Virus, central Europe

    Czech Academy of Sciences Publication Activity Database

    Bakonyi, T.; Hubálek, Zdeněk; Rudolf, Ivo; Nowotny, N.

    2005-01-01

    Roč. 11, č. 2 (2005), s. 225-231 ISSN 1080-6040. [International Conference on Emerging Infectious Diseases . Al Ain, 26.02.2005-01.03.2005] R&D Projects: GA ČR(CZ) GA206/03/0726 Institutional research plan: CEZ:AV0Z60930519 Keywords : epidemiology * West Nile virus * Central Europe Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 5.308, year: 2005 http://www.cdc.gov/ncidod/EID/vol11no02/04-1028.htm

  9. Rapid Active Assay for the Detection of Antibodies to West Nile Virus in Chickens

    Science.gov (United States)

    2008-01-01

    and organ donations ,9 breast feeding,10 intrauterine exposure,11 and laboratory pro- cedures,12 emphasizing the importance of developing a rapid and... milk in 20 mmol/L Tris-HCl, 0.15 mol/L NaCl, and 0.05% Tween-20, pH 7.5) was applied to the plates, followed by incubation at room temperature for 30...884–895. 10. Centers for Disease Control and Prevention, 2002. Possible West Nile virus transmission to an infant through breast -feeding— Michigan, 2002

  10. First detection of West Nile virus in domestic pigeon in Korea.

    Science.gov (United States)

    Kim, C-Yoon; Oh, Hanseul; Song, Juha; Hur, Moonsuk; Suh, Jae-Hwa; Jheong, Weon-Hwa; Kim, Jong-Taek; Oh, Hong-Shik; Park, Jae-Hak

    2016-12-30

    West Nile virus (WNV) is a mosquito-borne zoonotic pathogen that has spread throughout Europe and the United States. Recently, WNV spread to East and Southeast Asia, and great efforts have been made in South Korea to prevent the spread of WNV from neighboring countries. In this study, we diagnosed the first case of WNV in pigeons ( Columba livia domestica ) residing in cities using a competitive enzyme-linked immunosorbent assay and confirmed it with nested reverse transcription polymerase chain reaction analysis and sequencing. This is the first report to provide convincing evidence that WNV is present within South Korea.

  11. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Experimental susceptibility of Wood Ducks (Aix sponsa) for West Nile virus

    Science.gov (United States)

    Hofmeister, Erik K.; Porter, Robert E.; Franson, J. Christian

    2015-01-01

    Detection of West Nile virus (WNV) has been reported in a variety of wild ducks in the US, but little is known about the pathogenesis and outcome of exposure of the disease in these species. Previous experimental studies of WNV in ducks either have challenged a small number of ducks with WNV or have tested domesticated ducks. To determine susceptibility and immune response, we challenged 7-wk-old Wood Ducks (Aix sponsa) with a 1999 American Crow (Corvus brachyrhynchos) isolate of WNV. Wood Ducks were susceptible to infection with the virus, and, although clinical signs or mortality were not observed, microscopic lesions were noted, particularly in the heart and brain. West Nile virus viremia peaked on day 2 postinfection (pi) at 104.54 plaque-forming units (PFU) of virus/mL serum and WNV was shed orally (between 102and 102.9 PFU per swab) and cloacally. Specific anti-WNV antibody response was rapid, with anti-WNV IgM detected on day 3 pi followed on day 5 pi by anti-WNV IgG. Neutralizing antibodies were detected by plaque-reduction neutralization assay in one duck on day 4 pi, and in all sampled ducks on day 5. These results indicate that Wood Ducks are susceptible to WNV, but it is unlikely that significant WNV mortality events occur in Wood Ducks or that ducks play a significant role in transmission. However, WNV viremia was sufficient, in theory, to infect mosquitoes, and oral and cloacal shedding of the virus may increase the risk of infection to other waterbirds.

  13. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Prevalence of West Nile virus in migratory birds during spring and fall migration

    Science.gov (United States)

    Dusek, Robert J.; McLean, R.G.; Kramer, L.D.; Ubico, S.R.; Dupuis, A.P.; Ebel, G.D.; Guptill, S.C.

    2009-01-01

    To investigate the role of migratory birds in the dissemination of West Nile virus (WNV), we measured the prevalence of infectious WNV and specific WNV neutralizing antibodies in birds, principally Passeriformes, during spring and fall migrations in the Atlantic and Mississippi flyways from 2001-2003. Blood samples were obtained from 13,403 birds, representing 133 species. Specific WNV neutralizing antibody was detected in 254 resident and migratory birds, representing 39 species, and was most commonly detected in northern cardinals (Cardinalis cardinalis) (9.8%, N = 762) and gray catbirds (Dumetella carolinensis) (3.2%,N = 3188). West Nile virus viremias were detected in 19 birds, including 8 gray catbirds, and only during the fall migratory period. These results provide additional evidence that migratory birds may have been a principal agent for the spread of WNV in North America and provide data on the occurrence of WNV in a variety of bird species. Copyright ?? 2009 by The American Society of Tropical Medicine and Hygiene.

  16. West Nile Virus in the United States — A Historical Perspective

    Directory of Open Access Journals (Sweden)

    John T. Roehrig

    2013-12-01

    Full Text Available Prior to 1999, West Nile virus (WNV was a bit player in the screenplay of global vector-borne viral diseases. First discovered in the West Nile District of Uganda in 1937, this Culex sp.-transmitted virus was known for causing small human febrile outbreaks in Africa and the Middle East. Prior to 1995, the last major human WNV outbreak was in the 1950s in Israel. The epidemiology and ecology of WNV began to change in the mid-1990s when an epidemic of human encephalitis occurred in Romania. The introduction of WNV into Eastern Europe was readily explained by bird migration between Africa and Europe. The movement of WNV from Africa to Europe could not, however, predict its surprising jump across the Atlantic Ocean to New York City and the surrounding areas of the United States (U.S.. This movement of WNV from the Eastern to Western Hemisphere in 1999, and its subsequent dissemination throughout two continents in less than ten years is widely recognized as one of the most significant events in arbovirology during the last two centuries. This paper documents the early events of the introduction into and the spread of WNV in the Western Hemisphere.

  17. Detection of West Nile virus lineage 2 in the urine of acute human infections.

    Science.gov (United States)

    Papa, Anna; Testa, Theodolinda; Papadopoulou, Elpida

    2014-12-01

    West Nile virus (WNV) lineage 2 emerged in Greece in 2010 and since then outbreaks in humans have been reported for four consecutive years. Laboratory diagnosis is based mainly on serology. A real-time RT-PCR was applied on urine samples obtained from 35 patients with acute WNV infection. WNV RNA was detected in 40% of the samples with cycle threshold (CT) values ranging from 26.95 to 39.89 (mean 33.11). WNV was isolated from two of four urine samples with low CT (sample shipment and storage conditions are very important for virus detection and isolation. The usefulness of the WNV RNA detection in urine as a diagnostic tool of acute WNV infections is discussed. © 2014 Wiley Periodicals, Inc.

  18. Seroprevalence of West Nile Virus in feral horses on Sheldon National Wildlife Refuge, Nevada, United States

    Science.gov (United States)

    Franson, J. Christian; Hofmeister, Erik K.; Collins, Gail H.; Dusek, Robert J.

    2011-01-01

    We screened 1,397 feral horses (Equus caballus) on Sheldon National Wildlife Refuge, Nevada, United States, for IgM and IgG against flavivirus during 2004–2006, 2008, and 2009. Positive serum samples were tested for neutralizing antibodies to West Nile virus (WNV) and St. Louis encephalitis virus (SLEV). One animal was positive for antibody against WNV in 2004, but all others tested in 2004–2006 were negative. In 2008 and 2009, we found evidence of increasing seropositive horses with age, whereas seroprevalence of WNV decreased from 19% in 2008 to 7.2% in 2009. No horses were positive for antibody against SLEV. Being unvaccinated, feral horses can be useful for WNV surveillance.

  19. Characterization of the functional requirements of West Nile virus membrane fusion.

    Science.gov (United States)

    Moesker, Bastiaan; Rodenhuis-Zybert, Izabela A; Meijerhof, Tjarko; Wilschut, Jan; Smit, Jolanda M

    2010-02-01

    Flaviviruses infect their host cells by a membrane fusion reaction. In this study, we performed a functional analysis of the membrane fusion properties of West Nile virus (WNV) with liposomal target membranes. Membrane fusion was monitored continuously using a lipid mixing assay involving the fluorophore, pyrene. Fusion of WNV with liposomes occurred on the timescale of seconds and was strictly dependent on mildly acidic pH. Optimal fusion kinetics were observed at pH 6.3, the threshold for fusion being pH 6.9. Preincubation of the virus alone at pH 6.3 resulted in a rapid loss of fusion capacity. WNV fusion activity is strongly promoted by the presence of cholesterol in the target membrane. Furthermore, we provide direct evidence that cleavage of prM to M is a requirement for fusion activity of WNV.

  20. Occurrence of West Nile virus infection in raptors at the Salton Sea, California

    Science.gov (United States)

    Dusek, Robert J.; Iko, William M.; Hofmeister, Erik K.

    2010-01-01

    We investigated the prevalence of West Nile virus (WNV)-neutralizing antibodies and infectious virus, and the occurrence of overwinter transmission in two raptor species during January and March 2006 at the Salton Sea, Imperial County, California. We captured 208 American Kestrels (Falco sparverius) (January, n=100; March, n=108) and 116 Burrowing Owls (Athene cunicularia) (January, n=52; March, n=64). Laboratory analysis revealed that 83% of American Kestrels and 31% of Burrowing Owls were positive for WNV-neutralizing antibodies. Additionally, two seroconversions were detected in Burrowing Owls between January and March. Infectious WNV, consistent with acute infection, was not detected in any bird.

  1. West Nile Virus Surveillance in 2013 via Mosquito Screening in Northern Italy and the Influence of Weather on Virus Circulation

    Science.gov (United States)

    Calzolari, Mattia; Pautasso, Alessandra; Montarsi, Fabrizio; Albieri, Alessandro; Bellini, Romeo; Bonilauri, Paolo; Defilippo, Francesco; Lelli, Davide; Moreno, Ana; Chiari, Mario; Tamba, Marco; Zanoni, Mariagrazia; Varisco, Giorgio; Bertolini, Silvia; Modesto, Paola; Radaelli, Maria Cristina; Iulini, Barbara; Prearo, Marino; Ravagnan, Silvia; Cazzin, Stefania; Mulatti, Paolo; Monne, Isabella; Bonfanti, Lebana; Marangon, Stefano; Goffredo, Maria; Savini, Giovanni; Martini, Simone; Mosca, Andrea; Farioli, Marco; Gemma Brenzoni, Laura; Palei, Manlio; Russo, Francesca; Natalini, Silvano; Angelini, Paola; Casalone, Cristina; Dottori, Michele; Capelli, Gioia

    2015-01-01

    West Nile virus (WNV) is a recently re-emerged health problem in Europe. In Italy, an increasing number of outbreaks of West Nile disease, with occurrences of human cases, have been reported since 2008. This is particularly true in northern Italy, where entomological surveillance systems have been implemented at a regional level. The aim of this study was to use, for the first time, all the entomological data collected in the five regions undergoing surveillance for WNV in northern Italy to characterize the viral circulation (at a spatial and temporal scale), identify potential mosquito vectors, and specify relationships between virus circulation and meteorological conditions. In 2013, 286 sites covering the entire Pianura Padana area were monitored. A total of 757,461 mosquitoes were sampled. Of these, 562,079 were tested by real-time PCR in 9,268 pools, of which 180 (1.9%) were positive for WNV. The largest part of the detected WNV sequences belonged to lineage II, demonstrating that, unlike those in the past, the 2013 outbreak was mainly sustained by this WNV lineage. This surveillance also detected the Usutu virus, a WNV-related flavivirus, in 241 (2.6%) pools. The WNV surveillance systems precisely identified the area affected by the virus and detected the viral circulation approximately two weeks before the occurrence of onset of human cases. Ninety percent of the sampled mosquitoes were Culex pipiens, and 178/180 WNV-positive pools were composed of only this species, suggesting this mosquito is the main WNV vector in northern Italy. A significantly higher abundance of the vector was recorded in the WNV circulation area, which was characterized by warmer and less rainy conditions and greater evapotranspiration compared to the rest of the Pianura Padana, suggesting that areas exposed to these conditions are more suitable for WNV circulation. This observation highlights warmer and less rainy conditions as factors able to enhance WNV circulation and cause virus

  2. Comparison of assays for the detection of West Nile virus antibodies in equine serum after natural infection or vaccination

    Czech Academy of Sciences Publication Activity Database

    Joó, K.; Bakonyi, T.; Szenci, O.; Ferenczi, E.; Barna, M.; Malik, P.; Hubálek, Zdeněk; Fehér, O.; Kutasi, O.

    2017-01-01

    Roč. 183, č. 1 (2017), s. 1-6 ISSN 0165-2427 Institutional support: RVO:68081766 Keywords : West Nile virus * Haemagglutination-inhibition test * Enzymelinked immunosorbent assay * Plaque reduction neutralization test * Vaccination * Natural infection Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology OBOR OECD: Immunology Impact factor: 1.718, year: 2016

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

    Science.gov (United States)

    Harasym, Carol A

    2008-11-01

    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.

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

    Science.gov (United States)

    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. PMID:19183740

  5. 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.

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

    Directory of Open Access Journals (Sweden)

    Yunoki M

    2016-07-01

    Full Text Available Mikihiro Yunoki,1-3 Takeshi Kurosu,2 Ritsuko Kubota Koketsu,2,4 Kazuo Takahashi,5 Yoshinobu Okuno,4 Kazuyoshi Ikuta2,4 1Research and Development Division, Japan Blood Products Organization, Tokyo, 2Department of Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, 3Pathogenic Risk Evaluation, Graduate School of Veterinary Medicine, Rakuno Gakuen University, Hokkaido, 4Research and Development Division, The Research Foundation for Microbial Diseases of Osaka University, Kagawa, 5Osaka Prefectural Institute of Public Health, Osaka, Japan Abstract: 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. Keywords

  7. Noncoding Subgenomic Flavivirus RNA Is Processed by the Mosquito RNA Interference Machinery and Determines West Nile Virus Transmission by Culex pipiens Mosquitoes

    NARCIS (Netherlands)

    Goertz, G.P.; Fros, J.J.; Miesen, P.; Vogels, C.B.F.; Bent, M.L. van der; Geertsema, C.; Koenraadt, C.J.M.; Rij, R.P. van; Oers, M.M. van; Pijlman, G.P.

    2016-01-01

    Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5'-3' exoribonuclease

  8. Generating West Nile Virus from an Infectious Clone.

    Science.gov (United States)

    Vandergaast, Rianna; Fredericksen, Brenda L

    2016-01-01

    WNV infectious clones are valuable tools for elucidating WNV biology. Nevertheless, relatively few infectious WNV clones have been generated because their construction is hampered by the instability of flaviviral genomes. More recently, advances in cloning techniques as well as the development of several two-plasmid WNV infectious clone systems have facilitated the generation of WNV infectious clones. Here we described a protocol for recovering WNV from a two-plasmid system. In this approach, large quantities of these constructs are digested with restriction enzymes to produce complementary restriction sites at the 3' end of the upstream fragment and the 5' end of the downstream fragment. These fragments are then annealed to produce linear template for in vitro transcription to synthesize infectious RNA. The resulting RNA is transfected into cells and after several days WNV is recovered in the culture supernatant. This method can be used to generate virus from infectious clones encoding high- and low-pathogenicity strains of WNV, as well as chimeric virues.

  9. Serosurveillance for Japanese encephalitis and West Nile viruses in resident birds in Hawai'i.

    Science.gov (United States)

    Nemeth, Nicole M; Bosco-Lauth, Angela M; Sciulli, Rebecca H; Gose, Remedios B; Nagata, Mark T; Bowen, Richard A

    2010-04-01

    Japanese encephalitis virus (JEV) and West Nile virus (WNV) are emerging zoonotic arboviruses that have recently undergone intercontinental expansion. Both JEV and WNV are naturally transmitted between mosquito vectors and vertebrate reservoir hosts, including birds. A potential route of JEV introduction from Asia to western North America is via the Hawaiian archipelago, while the spread of WNV from mainland North America to Hawai'i is also considered an impending threat. We surveyed resident, non-native bird sera for antibodies to JEV and WNV on two Hawaiian Islands from 2004-2005. Three of 1,835 birds (0.16%) had evidence of antiflavivirus antibodies, demonstrating neutralizing activity to JEV and St. Louis encephalitis virus (SLEV). These detections could represent a limited transmission focus of either, or both, JEV and SLEV, or cross-reactive antibodies due to primary infection with an alternate flavivirus. Frequent air traffic from both Asia and North America to Hawai'i, along with the presence of probable competent vectors and amplifying vertebrate hosts in Hawai'i, increases the likelihood of introduction and maintenance of novel flaviviruses. Therefore, it is important to monitor for the presence of these viruses.

  10. Factors That Influence the Transmission of West Nile Virus in Florida.

    Science.gov (United States)

    Day, Jonathan F; Tabachnick, Walter J; Smartt, Chelsea T

    2015-09-01

    West Nile virus (WNV) was first detected in North America in New York City during the late summer of 1999 and was first detected in Florida in 2001. Although WNV has been responsible for widespread and extensive epidemics in human populations and epizootics in domestic animals and wildlife throughout North America, comparable epidemics have never materialized in Florida. Here, we review some of the reasons why WNV has yet to cause an extensive outbreak in Florida. The primary vector of mosquito-borne encephalitis virus in Florida is Culex nigripalpus Theobald. Rainfall, drought, and temperature are the primary factors that regulate annual populations of this species. Cx. nigripalpus is a competent vector of WNV, St. Louis encephalitis virus, and eastern equine encephalitis virus in Florida, and populations of this species can support focal amplification and transmission of these arboviruses. We propose that a combination of environmental factors influencing Cx. nigripalpus oviposition, blood-feeding behavior, and vector competence have limited WNV transmission in Florida to relatively small focal outbreaks and kept the state free of a major epidemic. Florida must remain vigilant to the danger from WNV, because a change in these environmental factors could easily result in a substantial WNV epidemic rivaling those seen elsewhere in the United States. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. 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.

  12. The impact of West Nile virus on the abundance of selected North American birds

    Directory of Open Access Journals (Sweden)

    Beard Raphaelle H

    2011-08-01

    Full Text Available Abstract Background The emergence of West Nile virus (WNV in North America has been associated with high mortality in the native avifauna and has raised concerns about the long-term impact of WNV on bird populations. Here, we present results from a longitudinal analysis of annual counts of six bird species, using North American Breeding Bird Survey data from ten states (1994 to 2010. We fit overdispersed Poisson models to annual counts. Counts from successive years were linked by an autoregressive process that depended on WNV transmission intensity (annual West Nile neuroinvasive disease reports and was adjusted by El Niño Southern Oscillation events. These models were fit using a Markov chain Monte Carlo algorithm. Results Model fit was mostly excellent, especially for American Crows, for which our models explained between 26% and 81% of the observed variance. The impact of WNV on bird populations was quantitatively evaluated by contrasting hypothetical count trajectories (omission of WNV with observed counts. Populations of American crows were most consistently affected with a substantial cumulative impact in six of ten states. The largest negative impact, almost 60%, was found in Illinois. A regionally substantial decline was also seen for American Robins and House Sparrows, while the other species appeared unaffected. Conclusions Our results confirm findings from previous studies that single out American Crows as the species most vulnerable to WNV infection. We discuss strengths and limitations of this and other methods for quantifying the impact of WNV on bird populations.

  13. Culex quinquefasciatus (Diptera: Culicidae as a potential West Nile virus vector in Tucson, Arizona: Blood meal analysis indicates feeding on both humans and birds

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    Margaret Zinser

    2004-06-01

    Full Text Available Most reports from the United States suggest Culex quinquefasciatus mosquitoes feed minimally on humans. Given the abundance of C. quinquefasciatus in residential Tucson and parts of metropolitan Phoenix, and the arrival of West Nile virus to this area, discovering the blood meal hosts of the local population is important. Using a sandwich ELISA technique, the local C. quinquefasciatus were found to feed on both humans and birds. This suggests they should be considered potential West Nile virus vectors.

  14. Low prevalence of hepatitis C virus infection in Amerindians from Western Venezuela

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    Francisca Monsalve-Castillo

    2007-02-01

    Full Text Available Previous studies have not found hepatitis C virus (HCV infection in Amerindians from Western Venezuela. A survey of 254 Bari and Yukpa natives aged 10-60 years (mean ± SD age = 35 ± 5.4 years from four communities, two Bari and two Yukpa, in this area were studied to assess the prevalence of antibodies to HCV (anti-HCV and HCV RNA among these indigenous populations. Serum samples were examined initially for anti-HCV by a four generation enzyme-linked immunosorbent assay (ELISA. Reactive samples were then tested using a third generation recombinant immunoblot assay (RIBA-3. Viral RNA was investigated in all immunoblot-reactive samples by a nested polymerase chain reaction (PCR method. Six (2.3% of 254 natives were positive by ELISA, one (2.2% of these reactive samples were positive by RIBA, and four (1.5% were indeterminate. Only two (0.8% were positive by PCR, corresponding to 1 (2.1% of 47 inhabitants of a Yukpa community and to 1 (2.2% of 45 subjects of a Bari community. Iatrogenic is thought to play a role in acquisition of the infection. The findings indicate a HCV focus of low endemicity and are compatible with a low degree of exposures of the natives to the virus. Studies are necessary to assess the risk factors for infection in these Amerindians.

  15. Role of Natural Killer and Gamma-Delta T cells in West Nile Virus Infection

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    Thomas Welte

    2013-09-01

    Full Text Available Natural Killer (NK cells and Gamma-delta T cells are both innate lymphocytes that respond rapidly and non-specifically to viral infection and other pathogens. They are also known to form a unique link between innate and adaptive immunity. Although they have similar immune features and effector functions, accumulating evidence in mice and humans suggest these two cell types have distinct roles in the control of infection by West Nile virus (WNV, a re-emerging pathogen that has caused fatal encephalitis in North America over the past decade. This review will discuss recent studies on these two cell types in protective immunity and viral pathogenesis during WNV infection.

  16. Severe neuroinvasive West Nile virus infection in a child with undiagnosed Addison's disease

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    Kevin Messacar

    2014-01-01

    Full Text Available This report describes a case of West Nile virus (WNV meningoencephalitis in a child who presented with fever, headache, seizures, and altered mental status, as well as hyponatremia and bronzing of the skin. Findings that led to the diagnosis of WNV included plasma-cell pleocytosis of the cerebrospinal fluid (CSF and linear chorioretinitis on ophthalmologic exam. The diagnosis was confirmed by a positive serum and CSF WNV IgM. The acute WNV infection triggered an adrenal crisis which uncovered a new diagnosis of underlying Addison's disease. This is the first case report of severe neuroinvasive WNV disease in a pediatric patient with primary adrenal insufficiency. Neuroinvasive WNV disease is uncommon in children, but may have a more severe presentation in those with certain underlying medical conditions.

  17. Phylogenetic analysis of West Nile virus isolated in Italy in 2008.

    Science.gov (United States)

    Savini, G; Monaco, F; Calistri, P; Lelli, R

    2008-11-27

    In Italy the first occurrence of West Nile virus (WNV) infection was reported in Tuscany region during the late summer of 1998. In August 2008, the WNV infection re-emerged in Italy, in areas surrounding the Po river delta, and involving three regions Lombardy, Emilia Romagna and Veneto. WNV was isolated from blood and organs samples of one horse, one donkey, one pigeon (Columba livia) and three magpies (Pica pica). The phylogenetic analysis of the isolates, conducted on 255 bp in the region coding for the E protein, indicates that these isolates belong to the lineage I among the European strains. According to the analysis, both the 1998 and 2008 Italian strains as well as isolates from Romania, Russia, Senegal and Kenya fell in the same sub-cluster.

  18. Clinical evaluation and outcomes of naturally acquired West Nile virus infection in raptors.

    Science.gov (United States)

    Nemeth, Nicole M; Kratz, Gail E; Bates, Rebecca; Scherpelz, Judy A; Bowen, Richard A; Komar, Nicholas

    2009-03-01

    West Nile virus (WNV) infection and associated disease and mortality have been documented in numerous North American raptor species. Information regarding clinical presentations and long-term outcomes of WNV-infected raptors is important in the clinic for the diagnosis, treatment, and assessment of prognosis, as well as for understanding potential population level effects on raptor species. Raptors of 22 species admitted to a rehabilitation clinic were tested, from 2002 to 2005, for previous and acute WNV infection, while comparing clinical syndromes, trauma, and rehabilitation outcomes. Forty-two percent of admitted raptors (132/314) had been infected with WNV, and these presented with a WNV-attributed clinical disease rate of 67.4% (89/132). West Nile virus-infected raptors were less likely to be released (79/132 [59.8%]) than negative raptors (138/182 [75.8%]) and more likely to die or be euthanized (47/132 [35.6%] for WNV-infected vs. 32/182 [17.6%] for WNV-negative). However, WNV-infected raptors with neurologic disease were no less likely to be released (29/53 [54.7%]) than those without neurologic disease (50/79 [63.3%]). Clinical WNV-associated syndromes varied among species. Great horned owls (Bubo virginianus) were more likely to have neurologic signs, whereas American kestrels (Falco sparverius) and Swainson's hawks (Buteo swainsonii) were less likely to have neurologic signs. These results suggest that free-ranging raptors are frequently infected with WNV and that clinical syndromes differ among species. WNV has potentially devastating effects on raptors; however, rehabilitation of WNV-infected raptors can lead to positive outcomes, even for those having had severe neurologic disease.

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

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    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.

  20. The costs of infection and resistance as determinants of West Nile virus susceptibility in Culex mosquitoes

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    Styer Linda M

    2011-10-01

    Full Text Available Abstract Background Understanding the phenotypic consequences of interactions between arthropod-borne viruses (arboviruses and their mosquito hosts has direct implications for predicting the evolution of these relationships and the potential for changes in epidemiological patterns. Although arboviruses are generally not highly pathogenic to mosquitoes, pathology has at times been noted. Here, in order to evaluate the potential costs of West Nile virus (WNV infection and resistance in a primary WNV vector, and to assess the extent to which virus-vector relationships are species-specific, we performed fitness studies with and without WNV exposure using a highly susceptible Culex pipiens mosquito colony. Specifically, we measured and compared survival, fecundity, and feeding rates in bloodfed mosquitoes that were (i infected following WNV exposure (susceptible, (ii uninfected following WNV exposure (resistant, or (iii unexposed. Results In contrast to our previous findings with a relatively resistant Cx. tarsalis colony, WNV infection did not alter fecundity or blood-feeding behaviour of Cx. pipiens, yet results do indicate that resistance to infection is associated with a fitness cost in terms of mosquito survival. Conclusions The identification of species-specific differences provides an evolutionary explanation for variability in vector susceptibility to arboviruses and suggests that understanding the costs of infection and resistance are important factors in determining the potential competence of vector populations for arboviruses.

  1. 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.

  2. Surveillance potential of non-native Hawaiian birds for detection of West Nile Virus

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    Hofmeister, Erik K.; Dusek, Robert J.; Brand, Christopher J.

    2015-01-01

    West Nile virus (WNV) was first detected in North America in 1999. Alaska and Hawaii (HI) remain the only U.S. states in which transmission of WNV has not been detected. Dead bird surveillance has played an important role in the detection of the virus geographically, as well as temporally. In North America, corvids have played a major role in WNV surveillance; however, the only corvid in HI is the endangered Hawaiian crow that exists only in captivity, thus precluding the use of this species for WNV surveillance in HI. To evaluate the suitability of alternate avian species for WNV surveillance, we experimentally challenged seven abundant non-native bird species present in HI with WNV and compared mortality, viremia, oral shedding of virus, and seroconversion. For detection of WNV in oral swabs, we compared viral culture, reverse-transcriptase polymerase chain reaction, and the RAMP® test. For detection of antibodies to WNV, we compared an indirect and a competitive enzyme-linked immunoassay. We found four species (house sparrow, house finch, Japanese white-eye, and Java sparrow) that may be useful in dead bird surveillance for WNV; while common myna, zebra dove, and spotted dove survived infection and may be useful in serosurveillance.

  3. West Nile Virus Surveillance in 2013 via Mosquito Screening in Northern Italy and the Influence of Weather on Virus Circulation.

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    Mattia Calzolari

    Full Text Available West Nile virus (WNV is a recently re-emerged health problem in Europe. In Italy, an increasing number of outbreaks of West Nile disease, with occurrences of human cases, have been reported since 2008. This is particularly true in northern Italy, where entomological surveillance systems have been implemented at a regional level. The aim of this study was to use, for the first time, all the entomological data collected in the five regions undergoing surveillance for WNV in northern Italy to characterize the viral circulation (at a spatial and temporal scale, identify potential mosquito vectors, and specify relationships between virus circulation and meteorological conditions. In 2013, 286 sites covering the entire Pianura Padana area were monitored. A total of 757,461 mosquitoes were sampled. Of these, 562,079 were tested by real-time PCR in 9,268 pools, of which 180 (1.9% were positive for WNV. The largest part of the detected WNV sequences belonged to lineage II, demonstrating that, unlike those in the past, the 2013 outbreak was mainly sustained by this WNV lineage. This surveillance also detected the Usutu virus, a WNV-related flavivirus, in 241 (2.6% pools. The WNV surveillance systems precisely identified the area affected by the virus and detected the viral circulation approximately two weeks before the occurrence of onset of human cases. Ninety percent of the sampled mosquitoes were Culex pipiens, and 178/180 WNV-positive pools were composed of only this species, suggesting this mosquito is the main WNV vector in northern Italy. A significantly higher abundance of the vector was recorded in the WNV circulation area, which was characterized by warmer and less rainy conditions and greater evapotranspiration compared to the rest of the Pianura Padana, suggesting that areas exposed to these conditions are more suitable for WNV circulation. This observation highlights warmer and less rainy conditions as factors able to enhance WNV circulation

  4. A Fatal Neuroinvasive West Nile Virus Infection in a Traveler Returning from Madagascar: Clinical, Epidemiological and Veterinary Investigations

    Science.gov (United States)

    Larrieu, Sophie; Cardinale, Eric; Ocquidant, Philippe; Roger, Matthieu; Lepec, Richard; Delatte, Hélène; Camuset, Guillaume; Desprès, Philippe; Brottet, Elise; Charlin, Cyril; Michault, Alain

    2013-01-01

    A 58-year-old woman living in Reunion Island and returning from Madagascar was hospitalized for neuroinvasive encephalitis and died 1 month later. West Nile virus (WNV) infection was biologically confirmed by detection of immunoglobulin M (IgM) reactive with WNV antigens in both cerebrospinal fluid and serum, and weak neutralizing activity was also detected. A veterinary survey performed in her traveling area showed a seroprevalence of WNV of 28.7% (95% confidence interval [CI] = 21.1–36.3) in adult poultry, confirming an active circulation of the virus. Development of a severe form could be related to a weak antibody response, because the patient presented low IgM and IgG titers. This case report underlines the constant risk of emergence of West Nile in Indian Ocean territories, including Reunion Island where competent vectors are widely present during the whole year. PMID:23751400

  5. West Nile virus replication requires fatty acid synthesis but is independent on phosphatidylinositol-4-phosphate lipids.

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    Miguel A Martín-Acebes

    Full Text Available West Nile virus (WNV is a neurovirulent mosquito-borne flavivirus, which main natural hosts are birds but it also infects equines and humans, among other mammals. As in the case of other plus-stranded RNA viruses, WNV replication is associated to intracellular membrane rearrangements. Based on results obtained with a variety of viruses, different cellular processes have been shown to play important roles on these membrane rearrangements for efficient viral replication. As these processes are related to lipid metabolism, fatty acid synthesis, as well as generation of a specific lipid microenvironment enriched in phosphatidylinositol-4-phosphate (PI4P, has been associated to it in other viral models. In this study, intracellular membrane rearrangements following infection with a highly neurovirulent strain of WNV were addressed by means of electron and confocal microscopy. Infection of WNV, and specifically viral RNA replication, were dependent on fatty acid synthesis, as revealed by the inhibitory effect of cerulenin and C75, two pharmacological inhibitors of fatty acid synthase, a key enzyme of this process. However, WNV infection did not induce redistribution of PI4P lipids, and PI4P did not localize at viral replication complex. Even more, WNV multiplication was not inhibited by the use of the phosphatidylinositol-4-kinase inhibitor PIK93, while infection by the enterovirus Coxsackievirus B5 was reduced. Similar features were found when infection by other flavivirus, the Usutu virus (USUV, was analyzed. These features of WNV replication could help to design specific antiviral approaches against WNV and other related flaviviruses.

  6. Stress hormones predict a host superspreader phenotype in the West Nile virus system

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    Gervasi, Stephanie; Burgan, Sarah; Hofmeister, Erik K.; Unnasch, Thomas R.; Martin, Lynn B.

    2017-01-01

    Glucocorticoid stress hormones, such as corticosterone (CORT), have profound effects on the behaviour and physiology of organisms, and thus have the potential to alter host competence and the contributions of individuals to population- and community-level pathogen dynamics. For example, CORT could alter the rate of contacts among hosts, pathogens and vectors through its widespread effects on host metabolism and activity levels. CORT could also affect the intensity and duration of pathogen shedding and risk of host mortality during infection. We experimentally manipulated songbird CORT, asking how CORT affected behavioural and physiological responses to a standardized West Nile virus (WNV) challenge. Although all birds became infected after exposure to the virus, only birds with elevated CORT had viral loads at or above the infectious threshold. Moreover, though the rate of mortality was faster in birds with elevated CORT compared with controls, most hosts with elevated CORT survived past the day of peak infectiousness. CORT concentrations just prior to inoculation with WNV and anti-inflammatory cytokine concentrations following viral exposure were predictive of individual duration of infectiousness and the ability to maintain physical performance during infection (i.e. tolerance), revealing putative biomarkers of competence. Collectively, our results suggest that glucocorticoid stress hormones could directly and indirectly mediate the spread of pathogens.

  7. Spatio-temporal epidemiology of human West Nile virus disease in South Dakota.

    Science.gov (United States)

    Wimberly, Michael C; Giacomo, Paolla; Kightlinger, Lon; Hildreth, Michael B

    2013-10-29

    Despite a cold temperate climate and low human population density, the Northern Great Plains has become a persistent hot spot for human West Nile virus (WNV) disease in North America. Understanding the spatial and temporal patterns of WNV can provide insights into the epidemiological and ecological factors that influence disease emergence and persistence. We analyzed the 1,962 cases of human WNV disease that occurred in South Dakota from 2002-2012 to identify the geographic distribution, seasonal cycles, and interannual variability of disease risk. The geographic and seasonal patterns of WNV have changed since the invasion and initial epidemic in 2002-2003, with cases shifting toward the eastern portion of South Dakota and occurring earlier in the transmission season in more recent years. WNV cases were temporally autocorrelated at lags of up to six weeks and early season cumulative case numbers were correlated with seasonal totals, indicating the possibility of using these data for short-term early detection of outbreaks. Epidemiological data are likely to be most effective for early warning of WNV virus outbreaks if they are integrated with entomological surveillance and environmental monitoring to leverage the strengths and minimize the weaknesses of each information source.

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

    Science.gov (United States)

    Fassbinder-Orth, C. A.; Hofmeister, Erik 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.

  9. A CRISPR-Based Screen Identifies Genes Essential for West-Nile-Virus-Induced Cell Death.

    Science.gov (United States)

    Ma, Hongming; Dang, Ying; Wu, Yonggan; Jia, Gengxiang; Anaya, Edgar; Zhang, Junli; Abraham, Sojan; Choi, Jang-Gi; Shi, Guojun; Qi, Ling; Manjunath, N; Wu, Haoquan

    2015-07-28

    West Nile virus (WNV) causes an acute neurological infection attended by massive neuronal cell death. However, the mechanism(s) behind the virus-induced cell death is poorly understood. Using a library containing 77,406 sgRNAs targeting 20,121 genes, we performed a genome-wide screen followed by a second screen with a sub-library. Among the genes identified, seven genes, EMC2, EMC3, SEL1L, DERL2, UBE2G2, UBE2J1, and HRD1, stood out as having the strongest phenotype, whose knockout conferred strong protection against WNV-induced cell death with two different WNV strains and in three cell lines. Interestingly, knockout of these genes did not block WNV replication. Thus, these appear to be essential genes that link WNV replication to downstream cell death pathway(s). In addition, the fact that all of these genes belong to the ER-associated protein degradation (ERAD) pathway suggests that this might be the primary driver of WNV-induced cell death. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Identification of environmental covariates of West Nile virus vector mosquito population abundance.

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    Trawinski, Patricia R; Mackay, D Scott

    2010-06-01

    The rapid spread of West Nile virus (WNv) in North America is a major public health concern. Culex pipiens-restuans is the principle mosquito vector of WNv in the northeastern United States while Aedes vexans is an important bridge vector of the virus in this region. Vector mosquito abundance is directly dependent on physical environmental factors that provide mosquito habitats. The objective of this research is to determine landscape elements that explain the population abundance and distribution of WNv vector mosquitoes using stepwise linear regression. We developed a novel approach for examining a large set of landscape variables based on a land use and land cover classification by selecting variables in stages to minimize multicollinearity. We also investigated the distance at which landscape elements influence abundance of vector populations using buffer distances of 200, 400, and 1000 m. Results show landscape effects have a significant impact on Cx. pipiens-estuans population distribution while the effects of landscape features are less important for prediction of Ae. vexans population distributions. Cx. pipiens-restuans population abundance is positively correlated with human population density, housing unit density, and urban land use and land cover classes and negatively correlated with age of dwellings and amount of forested land.

  11. Susceptibility of Carrion Crows to Experimental Infection with Lineage 1 and 2 West Nile Viruses.

    Science.gov (United States)

    Lim, Stephanie M; Brault, Aaron C; van Amerongen, Geert; Bosco-Lauth, Angela M; Romo, Hannah; Sewbalaksing, Varsha D; Bowen, Richard A; Osterhaus, Albert D M E; Koraka, Penelope; Martina, Byron E E

    2015-08-01

    West Nile virus (WNV) outbreaks in North America have been characterized by substantial die-offs of American crows (Corvus brachyrhynchos). In contrast, a low incidence of bird deaths has been observed during WNV epidemic activity in Europe. To examine the susceptibility of the western European counterpart of American crows, we inoculated carrion crows (Corvus corone) with WNV strains isolated in Greece (Gr-10), Italy (FIN and Ita09), and Hungary (578/10) and with the highly virulent North American genotype strain (NY99). We also inoculated American crows with a selection of these strains to examine the strains' virulence in a highly susceptible bird species. Infection with all strains, except WNV FIN, resulted in high rates of death and high-level viremia in both bird species and virus dissemination to several organs. These results suggest that carrion crows are highly susceptible to WNV and may potentially be useful as part of dead bird surveillance for early warning of WNV activity in Europe.

  12. Diverse host feeding on nesting birds may limit early-season West Nile virus amplification.

    Science.gov (United States)

    Egizi, Andrea M; Farajollahi, Ary; Fonseca, Dina M

    2014-06-01

    Arboviral activity tracks vector availability, which in temperate regions means that transmission ceases during the winter and must be restarted each spring. In the northeastern United States, Culex restuans Theobald resumes its activity earlier than Culex pipiens L. and is thought to be important in restarting West Nile virus (WNV) transmission. Its role in WNV amplification, however, is unclear, because viral levels commonly remain low until the rise of Cx. pipiens later in the season. Because a vector's feeding habits can reveal key information about disease transmission, we identified early-season (April-June) blood meals from Cx. restuans collected throughout New Jersey, and compared them to published datasets from later in the season and also from other parts of the country. We found significantly higher avian diversity, including poor WNV hosts, and fewer blood meals derived from American Robins (17% versus over 40% found in later season). Critically, we identified blood meals from significantly more female than male birds in species where females are the incubating sex, suggesting that Cx. restuans is able to feed on such a wide variety of hosts in early spring because incubating birds are easy targets. Because WNV amplification depends on virus consistently reaching competent hosts, our results indicate that Cx. restuans is unlikely to be an amplifying vector of WNV in the early season. As the season progresses, however, changes in the availability of nesting birds may make it just as capable as Cx. pipiens, although at somewhat lower abundance as the summer progresses.

  13. Naturally induced humoral immunity to West Nile virus infection in raptors.

    Science.gov (United States)

    Nemeth, Nicole M; Kratz, Gail E; Bates, Rebecca; Scherpelz, Judy A; Bowen, Richard A; Komar, Nicholas

    2008-09-01

    West Nile virus (WNV) infection can be fatal to many bird species, including numerous raptors, though population- and ecosystem-level impacts following introduction of the virus to North America have been difficult to document. Raptors occupy a diverse array of habitats worldwide and are important to ecosystems for their role as opportunistic predators. We documented initial (primary) WNV infection and then regularly measured WNV-specific neutralizing antibody titers in 16 resident raptors of seven species, plus one turkey vulture. Most individuals were initially infected and seroconverted between July and September of 2003, though three birds remained seronegative until summer 2006. Many of these birds became clinically ill upon primary infection, with clinical signs ranging from loss of appetite to moderate neurological disease. Naturally induced WNV neutralizing antibody titers remained essentially unchanged in some birds, while eight individuals experienced secondary rises in titer presumably due to additional exposures at 1, 2, or 3 years following primary infection. No birds experienced clinical signs surrounding or following the time of secondary exposure, and therefore antibodies were considered protective. Results of this study have implications for transmission dynamics of WNV and health of raptor populations, as well as the interpretation of serologic data from free-ranging and captive birds. Antibodies in raptors surviving WNV may persist for multiple years and protect against potential adverse effects of subsequent exposures.

  14. 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.

  15. 4EBP-Dependent Signaling Supports West Nile Virus Growth and Protein Expression

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    Katherine D. Shives

    2016-10-01

    Full Text Available West Nile virus (WNV is a (+ sense, single-stranded RNA virus in the Flavivirus genus. WNV RNA possesses an m7GpppNm 5′ cap with 2′-O-methylation that mimics host mRNAs preventing innate immune detection and allowing the virus to translate its RNA genome through the utilization of cap-dependent translation initiation effectors in a wide variety of host species. Our prior work established the requirement of the host mammalian target of rapamycin complex 1 (mTORC1 for optimal WNV growth and protein expression; yet, the roles of the downstream effectors of mTORC1 in WNV translation are unknown. In this study, we utilize gene deletion mutants in the ribosomal protein kinase called S6 kinase (S6K and eukaryotic translation initiation factor 4E-binding protein (4EBP pathways downstream of mTORC1 to define the role of mTOR-dependent translation initiation signals in WNV gene expression and growth. We now show that WNV growth and protein expression are dependent on mTORC1 mediated-regulation of the eukaryotic translation initiation factor 4E-binding protein/eukaryotic translation initiation factor 4E-binding protein (4EBP/eIF4E interaction and eukaryotic initiation factor 4F (eIF4F complex formation to support viral growth and viral protein expression. We also show that the canonical signals of mTORC1 activation including ribosomal protein s6 (rpS6 and S6K phosphorylation are not required for WNV growth in these same conditions. Our data suggest that the mTORC1/4EBP/eIF4E signaling axis is activated to support the translation of the WNV genome.

  16. Feeding patterns of potential West Nile virus vectors in south-west Spain.

    Directory of Open Access Journals (Sweden)

    Joaquín Muñoz

    Full Text Available Mosquito feeding behaviour determines the degree of vector-host contact and may have a serious impact on the risk of West Nile virus (WNV epidemics. Feeding behaviour also interacts with other biotic and abiotic factors that affect virus amplification and transmission.We identified the origin of blood meals in five mosquito species from three different wetlands in SW Spain. All mosquito species analysed fed with different frequencies on birds, mammals and reptiles. Both 'mosquito species' and 'locality' explained a similar amount of variance in the occurrence of avian blood meals. However, 'season of year' was the main factor explaining the presence of human blood meals. The differences in diet resulted in a marked spatial heterogeneity in the estimated WNV transmission risk. Culex perexiguus, Cx. modestus and Cx. pipiens were the main mosquito species involved in WNV enzootic circulation since they feed mainly on birds, were abundant in a number of localities and had high vector competence. Cx. perexiguus may also be important for WNV transmission to horses, as are Cx. pipiens and Cx. theileri in transmission to humans. Estimates of the WNV transmission risk based on mosquito diet, abundance and vector competence matched the results of previous WNV monitoring programs in the area. Our sensitivity analyses suggested that mosquito diet, followed by mosquito abundance and vector competence, are all relevant factors in understanding virus amplification and transmission risk in the studied wild ecosystems. At some of the studied localities, the risk of enzootic circulation of WNV was relatively high, even if the risk of transmission to humans and horses was less.Our results describe for first time the role of five WNV candidate vectors in SW Spain. Interspecific and local differences in mosquito diet composition has an important effect on the potential transmission risk of WNV to birds, horses and humans.

  17. 4EBP-Dependent Signaling Supports West Nile Virus Growth and Protein Expression.

    Science.gov (United States)

    Shives, Katherine D; Massey, Aaron R; May, Nicholas A; Morrison, Thomas E; Beckham, J David

    2016-10-18

    West Nile virus (WNV) is a (+) sense, single-stranded RNA virus in the Flavivirus genus. WNV RNA possesses an m7 GpppN m 5' cap with 2'- O -methylation that mimics host mRNAs preventing innate immune detection and allowing the virus to translate its RNA genome through the utilization of cap-dependent translation initiation effectors in a wide variety of host species. Our prior work established the requirement of the host mammalian target of rapamycin complex 1 (mTORC1) for optimal WNV growth and protein expression; yet, the roles of the downstream effectors of mTORC1 in WNV translation are unknown. In this study, we utilize gene deletion mutants in the ribosomal protein kinase called S6 kinase (S6K) and eukaryotic translation initiation factor 4E-binding protein (4EBP) pathways downstream of mTORC1 to define the role of mTOR-dependent translation initiation signals in WNV gene expression and growth. We now show that WNV growth and protein expression are dependent on mTORC1 mediated-regulation of the eukaryotic translation initiation factor 4E-binding protein/eukaryotic translation initiation factor 4E-binding protein (4EBP/eIF4E) interaction and eukaryotic initiation factor 4F (eIF4F) complex formation to support viral growth and viral protein expression. We also show that the canonical signals of mTORC1 activation including ribosomal protein s6 (rpS6) and S6K phosphorylation are not required for WNV growth in these same conditions. Our data suggest that the mTORC1/4EBP/eIF4E signaling axis is activated to support the translation of the WNV genome.

  18. Construction of self-replicating subgenomic West Nile virus replicons for screening antiviral compounds.

    Science.gov (United States)

    Alcaraz-Estrada, Sofia L; Reichert, Erin Donohue; Padmanabhan, Radhakrishnan

    2013-01-01

    Mosquito-borne flavivirus RNA genomes encode one long open reading frame flanking 5'- and 3'-untranslated regions (5'- and 3'-UTRs) which contain cis-acting RNA elements playing important roles for viral RNA translation and replication. The viral RNA encodes a single polyprotein, which is processed into three structural proteins and seven nonstructural (NS) proteins. The regions coding for the seven NS proteins are sufficient for replication of the RNA. The sequences encoding the structural genes can be deleted except for two short regions. The first one encompasses 32 amino acid (aa) residues from the N-terminal coding sequence of capsid (C) and the second, 27 aa region from the C-terminus of envelope (E) protein. The deleted region can be substituted with a gene coding for a readily quantifiable reporter to give rise to a subgenomic reporter replicon. Replicons containing a variety of reporter genes and marker genes for construction of stable mammalian cell lines are valuable reagents for studying the effects of mutations in translation and/or replication in isolation from processes like the entry and assembly of the virus particles. Here we describe the construction of two West Nile virus (WNV) replicons by overlap extension PCR and standard recombinant DNA techniques. One has a Renilla luciferase (Rluc) reporter gene followed by an internal ribosome entry site (element) for cap-independent translation of the open reading frame encompassing the carboxy-terminal sequence of E to NS5. The second replicon has in tandem the Rluc gene, foot and mouth disease virus 2A, and neomycin phosphotransferase gene that allows establishment of a stable mammalian cell line expressing the Rluc reporter in the presence of the neomycin analog, G418. The stable replicon-expressing Vero cell line has been used for cell-based screening and determination of EC50 values for antiviral compounds that inhibited WNV replication.

  19. Culex quinquefasciatus (Diptera: Culicidae) as a potential West Nile virus vector in Tucson, Arizona: Blood meal analysis indicates feeding on both humans and birds

    OpenAIRE

    Zinser, Margaret; Ramberg, Frank; Willott, Elizabeth

    2004-01-01

    Most reports from the United States suggest Culex quinquefasciatus mosquitoes feed minimally on humans. Given the abundance of C. quinquefasciatus in residential Tucson and parts of metropolitan Phoenix, and the arrival of West Nile virus to this area, discovering the blood meal hosts of the local population is important. Using a sandwich ELISA technique, the local C. quinquefasciatus were found to feed on both humans and birds. This suggests they should be considered potential West Nile viru...

  20. Serosurvey Reveals Exposure to West Nile Virus in Asymptomatic Horse Populations in Central Spain Prior to Recent Disease Foci.

    Science.gov (United States)

    Abad-Cobo, A; Llorente, F; Barbero, M Del Carmen; Cruz-López, F; Forés, P; Jiménez-Clavero, M Á

    2017-10-01

    West Nile fever/encephalitis (WNF) is an infectious disease affecting horses, birds and humans, with a cycle involving birds as natural reservoirs and mosquitoes as transmission vectors. It is a notifiable disease, re-emerging in Europe. In Spain, it first appeared in horses in the south (Andalusia) in 2010, where outbreaks occur every year since. However, in 2014, an outbreak was declared in horses in central Spain, approximately 200 km away from the closest foci in Andalusia. Before that, evidence of West Nile virus (WNV) circulation in central Spain had been obtained only from wildlife, but never in horses. The purpose of this work was to perform a serosurvey to retrospectively detect West Nile virus infections in asymptomatic horses in central Spain from 2011 to 2013, that is before the occurrence of the first outbreaks in the area. For that, serum samples from 369 horses, collected between September 2011 and November 2013 in central Spain, were analysed by ELISA (blocking and IgM) and confirmed by virus neutralization, proving its specificity using parallel titration with another flavivirus (Usutu virus). As a result, 10 of 369 horse serum samples analysed gave positive results by competitive ELISA, 5 of which were confirmed as positive to WNV by virus neutralization (seropositivity rate: 1.35%). One of these WNV seropositive samples was IgM-positive. Chronologically, the first positive samples, including the IgM-positive, corresponded to sera collected in 2012 in Madrid province. From these results, we concluded that WNV circulated in asymptomatic equine populations of central Spain at least since 2012, before the first disease outbreak reported in this area. © 2016 Blackwell Verlag GmbH.

  1. Overwintering of Uranotaenia unguiculata adult females in central Europe: a possible way of persistence of the putative new lineage of West Nile virus?

    Czech Academy of Sciences Publication Activity Database

    Rudolf, Ivo; Šebesta, Oldřich; Straková, Petra; Betášová, Lenka; Blažejová, Hana; Venclíková, Kristýna; Seidel, B.; Tóth, S.; Hubálek, Zdeněk; Schaffner, F.

    2015-01-01

    Roč. 31, č. 4 (2015), s. 364-365 ISSN 8756-971X EU Projects: European Commission(XE) 261504 - EDENEXT Institutional support: RVO:68081766 Keywords : mosquito * mosquito-borne viruses * overwintering * Uranotaenia unguiculata * West Nile virus Subject RIV: EE - Microbiology, Virology Impact factor: 0.824, year: 2015

  2. Decreasing prevalence of Hepatitis B and absence of Hepatitis C Virus infection in the Warao indigenous population of Venezuela

    Science.gov (United States)

    Blanco, Ruth Y.; Loureiro, Carmen L.; Sulbarán, Yoneira F.; Maes, Mailis; de Waard, Jacobus H.; Rangel, Héctor R.

    2018-01-01

    Prevalence and molecular epidemiology studies for hepatitis B (HBV) and C (HCV) virus are scarce in Warao Amerindians from Venezuela, where an epidemic of human immunodeficiency virus type 1 (HIV-1) has recently been documented. To carry out a molecular epidemiology analysis of hepatitis B (HBV) and C (HCV) virus in Warao individuals from the Delta Amacuro State of Venezuela. A total of 548 sera were tested for serological and molecular markers for HBV and HCV. The prevalence of active infection (presence of HBV surface antigen, HBsAg), exposure to HBV (presence of Antibody to HBV core antigen, anti-HBc) and anti-HCV, was 1.8%, 13% and 0% respectively. HBV exposure was significantly lower in men below 18 years old and also lower than rates previously reported in other Amerindian communities from Venezuela. Thirty one percent (31%, 25/80) of individuals without evidence of HBV infection exhibited anti-HBs titer ≥ 10U.I / ml, being significantly more frequent in individuals younger than 20 years. A higher HBV exposure was observed among HIV-1 positive individuals (33% vs 11%, p <0.005). A high prevalence of occult HBV infection was also observed (5.6%, 11/195). Phylogenetic analysis of S gene and complete HBV genomes showed that F3 is the only circulating subgenotype, different from the F2 subgenotype found in 1991 in this population. These results suggest a recent introduction of subgenotype F3, with a low divergence among the isolates. These results highlight the importance of molecular epidemiology studies for viral control, and support the effectiveness of vaccination in reducing transmission of HBV. PMID:29799873

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Antibody responses in humans infected with newly emerging strains of West Nile Virus in Europe.

    Directory of Open Access Journals (Sweden)

    Stefan Chabierski

    Full Text Available Infection with West Nile Virus (WNV affects an increasing number of countries worldwide. Although most human infections result in no or mild flu-like symptoms, the elderly and those with a weakened immune system are at higher risk for developing severe neurological disease. Since its introduction into North America in 1999, WNV has spread across the continental United States and caused annual outbreaks with a total of 36,000 documented clinical cases and ∼1,500 deaths. In recent years, outbreaks of neuroinvasive disease also have been reported in Europe. The WNV strains isolated during these outbreaks differ from those in North America, as sequencing has revealed that distinct phylogenetic lineages of WNV concurrently circulate in Europe, which has potential implications for the development of vaccines, therapeutics, and diagnostic tests. Here, we studied the human antibody response to European WNV strains responsible for outbreaks in Italy and Greece in 2010, caused by lineage 1 and 2 strains, respectively. The WNV structural proteins were expressed as a series of overlapping fragments fused to a carrier-protein, and binding of IgG in sera from infected persons was analyzed. The results demonstrate that, although the humoral immune response to WNV in humans is heterogeneous, several dominant peptides are recognized.

  5. West Nile Virus State of the Art Report of MALWEST Project

    Science.gov (United States)

    Marka, Andriani; Diamantidis, Alexandros; Papa, Anna; Valiakos, George; Chaintoutis, Serafeim C.; Doukas, Dimitrios; Tserkezou, Persefoni; Giannakopoulos, Alexios; Papaspyropoulos, Konstantinos; Patsoula, Eleni; Badieritakis, Evangelos; Baka, Agoritsa; Tseroni, Maria; Pervanidou, Danai; Papadopoulos, Nikos T.; Koliopoulos, George; Tontis, Dimitrios; Dovas, Chrysostomos I.; Billinis, Charalambos; Tsakris, Athanassios; Kremastinou, Jenny; Hadjichristodoulou, Christos

    2013-01-01

    During the last three years Greece is experiencing the emergence of West Nile virus (WNV) epidemics. Within this framework, an integrated surveillance and control programme (MALWEST project) with thirteen associate partners was launched aiming to investigate the disease and suggest appropriate interventions. One out of seven work packages of the project is dedicated to the State of the Art report for WNV. Three expert working groups on humans, animals and mosquitoes were established. Medical databases (PubMed, Scopus) were searched together with websites: e.g., WHO, CDC, ECDC. In total, 1,092 relevant articles were initially identified and 258 of them were finally included as references regarding the current knowledge about WNV, along with 36 additional sources (conference papers, reports, book chapters). The review is divided in three sections according to the fields of interest: (1) WNV in humans (epidemiology, molecular characteristics, transmission, diagnosis, treatment, prevention, surveillance); (2) WNV in animals (epidemiological and transmission characteristics concerning birds, horses, reptiles and other animal species) and (3) WNV in mosquitoes (control, surveillance). Finally, some examples of integrated surveillance programmes are presented. The introduction and establishment of the disease in Greece and other European countries further emphasizes the need for thorough research and broadening of our knowledge on this viral pathogen. PMID:24317379

  6. West Nile Virus Seroprevalence in the Greek Population in 2013: A Nationwide Cross-Sectional Survey

    Science.gov (United States)

    Hadjichristodoulou, Christos; Pournaras, Spyros; Mavrouli, Maria; Marka, Andriani; Tserkezou, Persefoni; Baka, Agoritsa; Billinis, Charalambos; Katsioulis, Antonios; Psaroulaki, Anna; Papa, Anna; Papadopoulos, Nikos; Mamuris, Zissis; Tsakris, Athanasios; Kremastinou, Jenny

    2015-01-01

    Cases of West Nile Virus (WNV) disease were recorded for three consecutive years in Greece following the year 2010 outbreak. A cross-sectional serologic survey was conducted to estimate the WNV seroprevalence and assess the ratio of infection to neuroinvasive disease. A stratified left-over sampling methodology was used including age and residence strata. A total of 3,962 serum samples was collected and tested for WNV Immunoglobulin G (IgG) antibodies by Enzyme–Linked Immunosorbent Assay (ELISA). All positive samples were further tested by Plaque Reduction Neutralization Test (PRNT) and WNV Immunoglobulin M (IgM) antibodies. WNV IgG antibodies were detected in 82 samples and 61 were also positive in PRNT representing a weighted seroprevalence of 2.1% (95% C.I.: 1.7–2.6) and 1.5% (95% C.I.: 1.2–2.0), respectively. Multivariable analysis showed that seroprevalence was associated with age and residence. The overall ratio of neuroinvasive disease to infected persons was estimated at 1:376 (95% C.I.: 1:421–1:338), while the elderly people had the highest ratio. This nationwide study provided valuable data regarding the epidemiology of WNV in Greece based on the fact that elderly people have higher risk of being both infected and having severe disease. PMID:26605539

  7. 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, Jeffrey 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.

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

    Directory of Open Access Journals (Sweden)

    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. Evaluation of Nucleic Acid Preservation Cards for West Nile Virus Testing in Dead Birds

    Science.gov (United States)

    Foss, Leslie; Reisen, William K.; Fang, Ying; Kramer, Vicki; Padgett, Kerry

    2016-01-01

    The California West Nile virus (WNV) Dead Bird Surveillance Program (DBSP) is an important component of WNV surveillance in the state. We evaluated FTA™ and RNASound™ cards as an alternative method for sampling dead birds for WNV molecular testing as these cards allow for more cost effective, rapid, and safer diagnostic sampling than the shipment of bird carcasses. To evaluate accuracy of results among avian sampling regimes, Reverse-Transcription Polymerase Chain Reaction (RT-PCR) results from FTA™ and RNASound™ cards were compared with results from kidney tissue, brain tissue, or oral swabs in lysis buffer in 2012–2013. In addition, RT-PCR results were compared with results from oral swabs tested by rapid antigen tests (RAMP™ and VecTOR™). While test results from the cards were not as sensitive as kidney tissue testing, they were more likely to provide accurate results than rapid antigen tests, and detected WNV in corvids as well as in other passerines, raptors, and waterfowl. Overall, WNV RT-PCR cycle threshold (Ct) scores from the cards were higher than those from tissue testing, but both card products displayed high sensitivity and specificity. American Crow samples provided the highest sensitivity. The cards also proved to be easier and more convenient vehicles for collecting and shipping samples, and in 2014 our program launched use of RNASound™ cards in the DBSP. Both FTA™ and RNASound™ products displayed 96% agreement with tissue results and are an adequate alternative sampling method for WNV dead bird testing. PMID:27341492

  10. Evaluation of Nucleic Acid Preservation Cards for West Nile Virus Testing in Dead Birds.

    Directory of Open Access Journals (Sweden)

    Leslie Foss

    Full Text Available The California West Nile virus (WNV Dead Bird Surveillance Program (DBSP is an important component of WNV surveillance in the state. We evaluated FTA™ and RNASound™ cards as an alternative method for sampling dead birds for WNV molecular testing as these cards allow for more cost effective, rapid, and safer diagnostic sampling than the shipment of bird carcasses. To evaluate accuracy of results among avian sampling regimes, Reverse-Transcription Polymerase Chain Reaction (RT-PCR results from FTA™ and RNASound™ cards were compared with results from kidney tissue, brain tissue, or oral swabs in lysis buffer in 2012-2013. In addition, RT-PCR results were compared with results from oral swabs tested by rapid antigen tests (RAMP™ and VecTOR™. While test results from the cards were not as sensitive as kidney tissue testing, they were more likely to provide accurate results than rapid antigen tests, and detected WNV in corvids as well as in other passerines, raptors, and waterfowl. Overall, WNV RT-PCR cycle threshold (Ct scores from the cards were higher than those from tissue testing, but both card products displayed high sensitivity and specificity. American Crow samples provided the highest sensitivity. The cards also proved to be easier and more convenient vehicles for collecting and shipping samples, and in 2014 our program launched use of RNASound™ cards in the DBSP. Both FTA™ and RNASound™ products displayed 96% agreement with tissue results and are an adequate alternative sampling method for WNV dead bird testing.

  11. Geographic Variability in Geocoding Success for West Nile Virus Cases in South Dakota

    Science.gov (United States)

    Wey, Christine L.; Griesse, Jennifer; Kightlinger, Lon; Wimberly, Michael C.

    2009-01-01

    Background Geocoding, the process of assigning each case a set of coordinates that closely approximates its true location, is an important component of spatial epidemiological studies. The failure to accurately geocode cases adversely affects the validity and strength of conclusions drawn from the analysis. We investigated whether there were differences among geographic locations and demographic classes in the ability to successfully geocode West Nile virus (WNV) cases in South Dakota. We successfully geocoded 1,354 cases (80.8%) to their street address locations and assigned all 1,676 cases to ZIP code tabulation areas (ZCTAs). Using spatial scan statistics, significant clusters of non-geocoded cases were identified in central and western South Dakota. Geocoding success rates were lower in areas of low population density and on Indian reservations than in other portions of the state. Geocoding success rates were lower for Native Americans than for other races. Spatial epidemiological studies should consider the potential biases that may result from excluding non-geocoded cases, particularly in rural portions of the Great Plains that contain large Native American populations. PMID:19577505

  12. 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.

  13. Entomologic investigations during an outbreak of West Nile virus disease in Maricopa County, Arizona, 2010.

    Science.gov (United States)

    Godsey, Marvin S; Burkhalter, Kristen; Young, Ginger; Delorey, Mark; Smith, Kirk; Townsend, John; Levy, Craig; Mutebi, John-Paul

    2012-12-01

    Entomologic investigations were conducted during an intense outbreak of West Nile virus (WNV) disease in Maricopa County, Arizona during July 31-August 9, 2010. The investigations compared the East Valley outbreak area, and a demographically similar control area in northwestern metropolitan Phoenix where no human cases were reported. Five mosquito species were identified in each area, and species composition was similar in both areas. Significantly more Culex quinquefasciatus females were collected by gravid traps at Outbreak sites (22.2 per trap night) than at control sites (8.9 per trap night), indicating higher Cx. quinquefasciatus abundance in the outbreak area. Twenty-eight WNV TaqMan reverse transcription-polymerase chain reaction-positive mosquito pools were identified, including 24 of Cx. quinquefasciatus, 3 of Psorophora columbiae, and 1 of Culex sp. However, Cx. quinquefasciatus WNV infection rates did not differ between outbreak and control sites. At outbreak sites, 30 of 39 engorged Cx. quinquefasciatus had fed on birds, 8 of 39 on humans, and 1 of 39 on a lizard. At control sites, 20 of 20 identified blood meals were from birds. Data suggest that Cx. quinquefasciatus was the primary enzootic and epidemic vector of this outbreak. The most important parameters in the outbreak were vector abundance and blood meal analysis, which suggested more frequent contact between Cx. quinquefasciatus and human hosts in the outbreak area compared with the control area.

  14. West Nile virus blood transfusion-related infection despite nucleic acid testing.

    Science.gov (United States)

    Macedo de Oliveira, Alexandre; Beecham, Brady D; Montgomery, Susan P; Lanciotti, Robert S; Linnen, Jeffrey M; Giachetti, Cristina; Pietrelli, Larry A; Stramer, Susan L; Safranek, Thomas J

    2004-12-01

    A case of West Nile virus (WNV) encephalitis associated with transfusion of blood that did not react when tested for WNV by minipool (MP) nucleic acid testing (NAT) is described. A Nebraska man developed clinical encephalitis 13 days after surgery and transfusion of 26 blood components. Antibody testing confirmed WNV infection. An investigation was initiated to determine the source of this infection. The patient's family members were interviewed to identify risk factors for WNV infection. Residual samples were retested for WNV RNA using transcription-mediated amplification (TMA) assay and two polymerase chain reaction (PCR) assays. Blood donors' follow-up serum samples were collected. All samples were tested for WNV-specific immunoglobulin M antibodies. The patient's family denied recent mosquito exposure. The 20 blood components collected after July 2003 did not react when tested for WNV in a six-member MP-NAT at the time of donation. Retrospective individual testing identified one sample as WNV-reactive by the TMA assay and one of the PCR assays. Seroconversion was demonstrated in the donor associated with this sample. WNV RNA detection by individual donation NAT demonstrates viremic blood escaping MP-NAT and supports transfusion-related WNV transmission. MP-NAT may not detect all WNV-infected blood donors, allowing WNV transmission to continue at low levels. WNV NAT assays might vary in sensitivity and pooling donations could further impact test performance. Understanding MP NAT limitations can improve strategies to maintain safety of the blood supply in the United States.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Blood group A and Rh(D)-negativity are associated with symptomatic West Nile virus infection

    Science.gov (United States)

    Kaidarova, Zhanna; Bravo, Marjorie D.; Kamel, Hany T.; Custer, Brian S; Busch, Michael P.; Lanteri, Marion C.

    2016-01-01

    Background West Nile virus (WNV) infection is mostly asymptomatic but 20% of subjects report WNV fever and 1% of patients experience neurological diseases with higher rates in elderly and immunosuppressed persons. With no treatment and no vaccine to prevent the development of symptomatic infections, it is essential to understand prognostic factors influencing symptomatic disease outcome. Host genetic background has been linked to the development of WNV neuroinvasive disease. The present study investigates the association between the ABO and Rh(D) blood group status and WNV disease outcome. Study Design and Methods The distribution of blood groups was investigated within a cohort of 374 WNV+ blood donors including 244 asymptomatic (AS) and 130 symptomatic (S) WNV+ blood donors. Logistic regression analyses were used to examine associations between A, B, O and Rh(D) blood groups and WNV clinical disease outcome. Results Symptomatic WNV+ donors exhibited increased frequencies of blood group A (S 47.6% AS 36.8%, P=0.04, OR [95%CI] 1.56 [1.01–2.40]) and Rh(D)-negative individuals (S 21.5% AS 13.1%, P=0.03, OR [95%CI] 1.82 [1.04–3.18]). Conclusion The findings suggest a genetic susceptibility placing blood group A and Rh(D)-negative individuals at risk for the development of symptomatic disease outcome after WNV infection. PMID:27189860

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

    Directory of Open Access Journals (Sweden)

    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.

  18. West Nile Virus State of the Art Report of MALWEST Project

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    Andriani Marka

    2013-12-01

    Full Text Available During the last three years Greece is experiencing the emergence of West Nile virus (WNV epidemics. Within this framework, an integrated surveillance and control programme (MALWEST project with thirteen associate partners was launched aiming to investigate the disease and suggest appropriate interventions. One out of seven work packages of the project is dedicated to the State of the Art report for WNV. Three expert working groups on humans, animals and mosquitoes were established. Medical databases (PubMed, Scopus were searched together with websites: e.g., WHO, CDC, ECDC. In total, 1,092 relevant articles were initially identified and 258 of them were finally included as references regarding the current knowledge about WNV, along with 36 additional sources (conference papers, reports, book chapters. The review is divided in three sections according to the fields of interest: (1 WNV in humans (epidemiology, molecular characteristics, transmission, diagnosis, treatment, prevention, surveillance; (2 WNV in animals (epidemiological and transmission characteristics concerning birds, horses, reptiles and other animal species and (3 WNV in mosquitoes (control, surveillance. Finally, some examples of integrated surveillance programmes are presented. The introduction and establishment of the disease in Greece and other European countries further emphasizes the need for thorough research and broadening of our knowledge on this viral pathogen.

  19. Inhibition of West Nile virus by calbindin-D28k.

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    Venkatraman Siddharthan

    Full Text Available Evidence indicates that West Nile virus (WNV employs Ca(2+ influx for its replication. Moreover, calcium buffer proteins, such as calbindin D28k (CB-D28k, may play an important role mitigating cellular destruction due to disease processes, and more specifically, in some neurological diseases. We addressed the hypothesis that CB-D28k inhibits WNV replication in cell culture and infected rodents. WNV envelope immunoreactivity (ir was not readily co-localized with CB-D28k ir in WNV-infected Vero 76 or motor neuron-like NSC34 cells that were either stably or transiently transfected with plasmids coding for CB-D28k gene. This was confirmed in cultured cells fixed on glass coverslips and by flow cytometry. Moreover, WNV infectious titers were reduced in CB-D28k-transfected cells. As in cell culture studies, WNV env ir was not co-localized with CB-D28k ir in the cortex of an infected WNV hamster, or in the hippocampus of an infected mouse. Motor neurons in the spinal cord typically do not express CB-D28k and are susceptible to WNV infection. Yet, CB-D28k was detected in the surviving motor neurons after the initial phase of WNV infection in hamsters. These data suggested that induction of CB-D28k elicit a neuroprotective response to WNV infection.

  20. 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. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  1. Spatial distribution of West Nile virus in humans and mosquitoes in Israel, 2000-2014.

    Science.gov (United States)

    Lustig, Yaniv; Kaufman, Zalman; Mendelson, Ella; Orshan, Laor; Anis, Emilia; Glazer, Yael; Cohen, Daniel; Shohat, Tamy; Bassal, Ravit

    2017-11-01

    Israel has a long history of West Nile virus (WNV) morbidity, and the rate of detection of WNV in mosquitoes has been high since 2000. The aim of this study was to integrate several WNV datasets in order to gain an insight into the geographical distribution of WNV in Israel. Three choropleth maps were generated showing WNV human morbidity, WNV prevalence in mosquitoes, and the results of a nationwide serological survey, based on the division of Israel into 15 sub-districts. The maps show a high endemicity of WNV in Israel. In respect to the morbidity map, the population residing in the central part of the country and in Arava Region is at higher risk of developing the disease than the population of the rest of Israel. Interestingly, high prevalence rates of both WNV serology and WNV-infected mosquitoes were detected in Arava Region, but lower prevalence rates were detected in most areas of the coastal region, suggesting that other factors might also be important in the development of symptomatic WNV infections. These results underline the high prevalence of WNV in Israel and point to specific risk areas for WNV infections across the country. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  2. Terminal structures of West Nile virus genomic RNA and their interactions with viral NS5 protein

    International Nuclear Information System (INIS)

    Dong Hongping; Zhang Bo; Shi Peiyong

    2008-01-01

    Genome cyclization is essential for flavivirus replication. We used RNases to probe the structures formed by the 5'-terminal 190 nucleotides and the 3'-terminal 111 nucleotides of the West Nile virus (WNV) genomic RNA. When analyzed individually, the two RNAs adopt stem-loop structures as predicted by the thermodynamic-folding program. However, when mixed together, the two RNAs form a duplex that is mediated through base-pairings of two sets of RNA elements (5'CS/3'CSI and 5'UAR/3'UAR). Formation of the RNA duplex facilitates a conformational change that leaves the 3'-terminal nucleotides of the genome (position - 8 to - 16) to be single-stranded. Viral NS5 binds specifically to the 5'-terminal stem-loop (SL1) of the genomic RNA. The 5'SL1 RNA structure is essential for WNV replication. The study has provided further evidence to suggest that flavivirus genome cyclization and NS5/5'SL1 RNA interaction facilitate NS5 binding to the 3' end of the genome for the initiation of viral minus-strand RNA synthesis

  3. Land cover variation and West Nile virus prevalence: Patterns, processes, and implications for disease control

    Science.gov (United States)

    Ezenwa, V.O.; Milheim, L.E.; Coffey, M.F.; Godsey, M.S.; King, R.J.; Guptill, S.C.

    2007-01-01

    Identifying links between environmental variables and infectious disease risk is essential to understanding how human-induced environmental changes will effect the dynamics of human and wildlife diseases. Although land cover change has often been tied to spatial variation in disease occurrence, the underlying factors driving the correlations are often unknown, limiting the applicability of these results for disease prevention and control. In this study, we described associations between land cover composition and West Nile virus (WNV) infection prevalence, and investigated three potential processes accounting for observed patterns: (1) variation in vector density; (2) variation in amplification host abundance; and (3) variation in host community composition. Interestingly, we found that WNV infection rates among Culex mosquitoes declined with increasing wetland cover, but wetland area was not significantly associated with either vector density or amplification host abundance. By contrast, wetland area was strongly correlated with host community composition, and model comparisons suggested that this factor accounted, at least partially, for the observed effect of wetland area on WNV infection risk. Our results suggest that preserving large wetland areas, and by extension, intact wetland bird communities, may represent a valuable ecosystem-based approach for controlling WNV outbreaks. ?? Mary Ann Liebert, Inc.

  4. Wolbachia enhances West Nile virus (WNV infection in the mosquito Culex tarsalis.

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    Brittany L Dodson

    2014-07-01

    Full Text Available Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain on infection, dissemination and transmission of West Nile virus (WNV in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

  5. Genetic History of Hepatitis C Virus in Venezuela: High Diversity and Long Time of Evolution of HCV Genotype 2

    Science.gov (United States)

    Sulbarán, Maria Z.; Di Lello, Federico A.; Sulbarán, Yoneira; Cosson, Clarisa; Loureiro, Carmen L.; Rangel, Héctor R.; Cantaloube, Jean F.; Campos, Rodolfo H.; Moratorio, Gonzalo; Cristina, Juan; Pujol, Flor H.

    2010-01-01

    Background The subtype diversity of the hepatitis C virus (HCV) genotypes is unknown in Venezuela. Methodology/Principal Findings Partial sequencing of the NS5B region was performed in 310 isolates circulating in patients from 1995 to 2007. In the samples collected between 2005 and 2007, HCV genotype 1 (G1) was the most common genotype (63%), composed as expected of mainly G1a and G1b. G2 was the second most common genotype (33%), being G2a almost absent and G2j the most frequent subtype. Sequence analysis of the core region confirmed the subtype assignment performed within the NS5b region in 63 isolates. The complete genome sequence of G2j was obtained. G2j has been described in France, Canada and Burkina Fasso, but it was not found in Martinique, where several subtypes of G2 circulate in the general population. Bayesian coalescence analysis indicated a most recent common ancestor (MRCA) of G2j around 1785, before the introduction of G1b (1869) and G1a (1922). While HCV G1a and G1b experienced a growth reduction since 1990, coincident with the time when blood testing was implemented in Venezuela, HCV G2j did not seem to reach growth equilibrium during this period. Conclusions/Significance Assuming the introduction of G2j from Africa during the slave trade, the high frequency of G2j found in Venezuela could suggest: 1- the introduction of African ethnic groups different from the ones introduced to Martinique or 2- the occurrence of a founder effect. This study represents an in-depth analysis of the subtype diversity of HCV in Venezuela, which is still unexplored in the Americas and deserves further studies. PMID:21179440

  6. Genetic history of hepatitis C virus in Venezuela: high diversity and long time of evolution of HCV genotype 2.

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    Maria Z Sulbarán

    Full Text Available BACKGROUND: The subtype diversity of the hepatitis C virus (HCV genotypes is unknown in Venezuela. METHODOLOGY/PRINCIPAL FINDINGS: Partial sequencing of the NS5B region was performed in 310 isolates circulating in patients from 1995 to 2007. In the samples collected between 2005 and 2007, HCV genotype 1 (G1 was the most common genotype (63%, composed as expected of mainly G1a and G1b. G2 was the second most common genotype (33%, being G2a almost absent and G2j the most frequent subtype. Sequence analysis of the core region confirmed the subtype assignment performed within the NS5b region in 63 isolates. The complete genome sequence of G2j was obtained. G2j has been described in France, Canada and Burkina Fasso, but it was not found in Martinique, where several subtypes of G2 circulate in the general population. Bayesian coalescence analysis indicated a most recent common ancestor (MRCA of G2j around 1785, before the introduction of G1b (1869 and G1a (1922. While HCV G1a and G1b experienced a growth reduction since 1990, coincident with the time when blood testing was implemented in Venezuela, HCV G2j did not seem to reach growth equilibrium during this period. CONCLUSIONS/SIGNIFICANCE: Assuming the introduction of G2j from Africa during the slave trade, the high frequency of G2j found in Venezuela could suggest: 1- the introduction of African ethnic groups different from the ones introduced to Martinique or 2- the occurrence of a founder effect. This study represents an in-depth analysis of the subtype diversity of HCV in Venezuela, which is still unexplored in the Americas and deserves further studies.

  7. Climate change projections of West Nile virus infections in Europe: implications for blood safety practices.

    Science.gov (United States)

    Semenza, Jan C; Tran, Annelise; Espinosa, Laura; Sudre, Bertrand; Domanovic, Dragoslav; Paz, Shlomit

    2016-03-08

    West Nile virus (WNV) is transmitted by mosquitoes in both urban as well as in rural environments and can be pathogenic in birds, horses and humans. Extrinsic factors such as temperature and land use are determinants of WNV outbreaks in Europe, along with intrinsic factors of the vector and virus. With a multivariate model for WNV transmission we computed the probability of WNV infection in 2014, with July 2014 temperature anomalies. We applied the July temperature anomalies under the balanced A1B climate change scenario (mix of all energy sources, fossil and non-fossil) for 2025 and 2050 to model and project the risk of WNV infection in the future. Since asymptomatic infections are common in humans (which can result in the contamination of the donated blood) we estimated the predictive prevalence of WNV infections in the blood donor population. External validation of the probability model with 2014 cases indicated good prediction, based on an Area Under Curve (AUC) of 0.871 (SD = 0.032), on the Receiver Operating Characteristic Curve (ROC). The climate change projections for 2025 reveal a higher probability of WNV infection particularly at the edges of the current transmission areas (for example in Eastern Croatia, Northeastern and Northwestern Turkey) and an even further expansion in 2050. The prevalence of infection in (blood donor) populations in the outbreak-affected districts is expected to expand in the future. Predictive modelling of environmental and climatic drivers of WNV can be a valuable tool for public health practice. It can help delineate districts at risk for future transmission. These areas can be subjected to integrated disease and vector surveillance, outreach to the public and health care providers, implementation of personal protective measures, screening of blood donors, and vector abatement activities.

  8. Immune response to the West Nile virus in aged non-human primates.

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    Anne M Wertheimer

    2010-12-01

    Full Text Available Risk of encephalitis from West Nile virus (WNV infection increases dramatically with age. Understanding the basis of this susceptibility requires development of suitable animal models. Here, we investigated the immune response to WNV in old non-human primates.We investigated clinical, immunological and virological correlates of WNV infection in aging non-human primates. Aged (17-30 yrs and adult (6-9 yrs Rhesus macaques (RM were challenged with WNV in the presence or the absence of the mosquito salivary gland extract (SGE to approximate natural infection. None of the 26 animals exhibited clinical signs of the disease. Quantitative PCR suggested discrete and short-lived viremia, but infectious virus was never isolated. There was markedly increased, age-independent, proliferation of CD3(- non-B cells, followed by B-cell proliferation, which correlated to the loss of detectable WNV genomes. Moreover, animals primed with mosquito salivary gland extract exhibited reduced circulating WNV RNA. While we found the expected age-associated reduction in T cell proliferation, adaptive immunity did not correlate with infection outcome. That was further confirmed in a cohort of thymectomized and/or CD8 T-cell depleted Cynomolgus macaques (CM; N = 15, who also failed to develop WNV disease.Results are consistent with strong and age-independent innate resistance of macaques against WNV challenge. This animal model is therefore not suitable for vaccine and therapeutic testing against WNV. However, understanding the basis of their innate resistance against WNV in macaques could provide helpful clues to improve anti-WNV protection of older adults.

  9. West Nile virus infection in American Robins: new insights on dose response.

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    Kaci K VanDalen

    Full Text Available West Nile virus (WNV is a vector-borne pathogen that was first detected in the United States in 1999. The natural transmission cycle of WNV involves mosquito vectors and avian hosts, which vary in their competency to transmit the virus. American robins are an abundant backyard species in the United States and appear to have an important role in the amplification and dissemination of WNV. In this study we examine the response of American robins to infection with various WNV doses within the range of those administered by some natural mosquito vectors. Thirty American robins were assigned a WNV dosage treatment and needle inoculated with 10(0.95 PFU, 10(1.26 PFU, 10(2.15 PFU, or 10(3.15 PFU. Serum samples were tested for the presence of infectious WNV and/or antibodies, while oral swabs were tested for the presence of WNV RNA. Five of the 30 (17% robins had neutralizing antibodies to WNV prior to the experiment and none developed viremia or shed WNV RNA. The proportion of WNV-seronegative birds that became viremic after WNV inoculation increased in a dose dependent manner. At the lowest dose, only 40% (2/5 of the inoculated birds developed productive infections while at the highest dose, 100% (7/7 of the birds became viremic. Oral shedding of WNV RNA followed a similar trend where robins inoculated with the lower two doses were less likely to shed viral RNA (25% than robins inoculated with one of the higher doses (92%. Viremia titers and morbidity did not increase in a dose dependent manner; only two birds succumbed to infection and, interestingly, both were inoculated with the lowest dose of WNV. It is clear that the disease ecology of WNV is a complex interplay of hosts, vectors, and viral dose delivered.

  10. Role of bird movements in the epidemiology of West Nile and avian influenza virus

    Science.gov (United States)

    Muzaffar, Sabir Bin; Hill, Nichola J.; Takekawa, John Y.; Perry, William M.; Smith, Lacy M.; Boyce, Walter M.

    2012-01-01

    Avian infl uenza virus (AIV) is infl uenced by site fi delity and movements of bird hosts. We examined the movement ecology of American crows (Corvus brachyrhynchos) as potential hosts for West Nile virus (WNV) and greater white-fronted geese (Anser albifrons frontalis) as potential hosts for AIVs. Research was based on radio-telemetry studies conducted in the Central Valley of California, USA. While crows were restricted to a small area of only a few square kilometers, the distribution of the geese encompassed the northern Central Valley. The crows used 1.5 to 3.5 different roosting areas monthly from February through October, revealing lower roost fi delity than the geese that used 1.1 to 1.5 roosting areas each month from November through March. The crows moved a mean distance of 0.11 to 0.49 km/month between their roosting sites and 2.5 to 3.9 km/month between roosting and feeding sites. In contrast, the geese moved 4.2 to 19.3 km/month between roosting areas, and their feeding range varied from 13.2 to 19.0 km/month. Our comparison of the ecological characteristics of bird movements suggests that the limited local movements of crows coupled with frequent turnover of roosts may result in persistence of focal areas for WNV infection. In contrast, widespread areas used by geese will provide regular opportunities for intermixing of AIVs over a much greater geographic area.

  11. 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.

  12. Experimental infection of Tilapia Lake Virus (TiLV) in Nile tilapia (Oreochromis niloticus) and red tilapia (Oreochromis spp.).

    Science.gov (United States)

    Tattiyapong, Puntanat; Dachavichitlead, Worawan; Surachetpong, Win

    2017-08-01

    Since 2015, a novel orthomyxo-like virus, tilapia lake virus (TiLV) has been associated with outbreaks of disease and massive mortality of cultured Nile and red tilapia (Oreochromis niloticus and Oreochromis spp., respectively) in Thailand. In this study, TiLV was isolated from field samples and propagated in the permissive E-11 cell line, with cytopathic effect (CPE) development within 3-5days post-inoculation. Electron micrographs of infected E-11 cells and fish tissues confirmed the rounded, enveloped virions of 60 to 80nm with characteristics very similar to those of Orthomyxoviridae. In vivo challenge studies showed that high mortality in Nile (86%) and red tilapia (66%) occurred within 4-12days post-infection. The virus was re-isolated from challenged fish tissues in the permissive cell line, and PCR analysis confirmed TiLV as a causative pathogen. The distinct histopathology of challenged fish included massive degeneration and inflammatory cell infiltration in the liver and brain as well as the presence of eosinophilic intracytoplasmic inclusions in hepatocytes and splenic cells. Our results fulfilled Koch's postulates and confirmed that TiLV is an etiologic agent of mass mortality of tilapia in Thailand. The emergence of this virus in many countries has helped increase awareness that it is a potential threat to tilapia aquacultured in Thailand, Asia, and worldwide. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Seroprevalence screening for the West Nile virus in Malaysia's Orang Asli population.

    Science.gov (United States)

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

    2014-12-17

    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 the WNV in Malaysia's Orang Asli population. Serum samples of 742 Orang Asli were collected in seven states in peninsular Malaysia. The samples were assessed to determine the seroprevalence of WNV immunoglobulin (Ig)G with the WNV IgG enzyme-linked immunosorbent assay (ELISA) method. For each individual, we documented the demographic factors. Anti-dengue and anti-tick-borne encephalitis virus IgG ELISA were also performed to rule out a cross reaction. All statistical analyses were performed using the GraphPad Prism 6 (GraphPad Software, Inc.); p values of less than 0.05 were considered significant. The serosurvey included 298 men (40.16%) and 444 women (59.84%) of Malaysia's Orang Asli. Anti-WNV IgG was found in 9 of the 742 samples (1.21%). The seroprevalence was 0.67% (2 of 298) in men and 1.58% (7 of 444) in women. The presence of anti-WNV IgG was found not to be associated with gender but, however, did correlate with age. The peak seroprevalence was found to be 2.06% (2 of 97) in individuals between 30 to 42 years of age. No previous studies have examined the seroprevalence of the WNV antibody in the human population in Malaysia, and no clinical reports of infections have been made. Screening for the WNV seroprevalence is very significant because of many risk factors contribute to the presence of WNV in Malaysia, such as the abundance of Culex mosquitoes as the main vector and a high degree of biodiversity, including migratory birds that serve as a reservoir to the virus.

  14. The seroprevalence of West Nile Virus in Israel: A nationwide cross sectional study.

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    Ravit Bassal

    Full Text Available West Nile Virus (WNV is endemic in Israel, affecting yearly 40-160 individuals. Israel is located on a central migratory path between Africa and Eurasia and most West Nile Fever (WNF cases reported in recent years were among residents of the coastal plain. The aim of the study was to evaluate the seroprevalence of WNV among the Israeli population and to assess correlates for WNV infection. A cross-sectional nationwide serologic survey was conducted using 3,145 serum samples collected by the national Israeli serum bank during 2011-2014, representing all age and population groups in Israel. Prevalence rates of WNV IgG antibodies were determined. Logistic regressions models were applied to assess the associations between demographic characteristics and WNV seropositivity. 350 samples were positive to WNV (11.1%; 95%CI: 10.0-12.3%. In the multivariable analysis, there was a significant association between seropositivity and the Arab population group vs. Jews and others (OR = 1.86, 95%CI: 1.37-2.52, the time lived in Israel [50-59 years vs. 0-9 years; OR = 10.80 (95%CI: 1.03-113.46 and ≥60 years vs. 0-9 years; OR = 14.00 (1.32-148.31] residence area] Coastal Plain, Inland Plain (Shfela and Great Rift Valley vs. Upper Galilee; OR = 2.24 (95%CI: 1.37-3.65, OR = 2.18 (95%CI: 1.18-4.03, OR = 1.90 (95%CI: 1.10-3.30, respectively [and rural vs. urban settlement (OR = 1.65, 95%CI: 1.26-2.16. People, who reside in the Coastal Plain, Inland Plain and Great Rift Valley, should be aware of the risk of contracting WNV and reduce exposure to mosquito bites, using insect repellents, and wearing protective clothing. The Ministry of Environmental Protection should be active in reducing the mosquito population by eliminating sources of standing water, a breeding ground for mosquitoes.

  15. 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

  16. A note on outbreak of cowpea mild mottle virus (CPMMV) in common bean in the River Nile State, Sudan

    International Nuclear Information System (INIS)

    Hamed, A. A.; Elkhair, J.; Elfaha, A.

    2010-01-01

    An outbreak of a devastating virus disease occurred in common ben (phaseolus vulgaris) in Berber area, the River Nile State, during the 2004/2005 cropping season, with symptoms of stunting and yellowing. The disease incidence reached a level of more than 85% in all visited fields. One hundred fifty symptomatic samples, collected from different fields at Hudeiba, Berber and Shendi were blotted on nitrocellulose membranes and tested for the presence of different viruses, using the tissue blot immunoassay (TBIA) technique. The results of the serological tests revealed that 95% of the samples were positive for cowpea mild mottle virus (CPMMV). Among the common bean genotypes screened for resistance to CPMMV, only RO/2/1 and Giza 3 were resistant to the disease.(Author)

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

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    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. Mosquito politics: local vector control policies and the spread of West Nile Virus in the Chicago region.

    Science.gov (United States)

    Tedesco, Carmen; Ruiz, Marilyn; McLafferty, Sara

    2010-11-01

    Differences in mosquito control practices at the local level involve the interplay of place, scale and politics. During the Chicago West Nile Virus (WNV) outbreak of 2002, mosquito abatement districts represent distinct suburban clusters of human WNV cases, independent of characteristics of the local population, housing and physical environment. We examine how the contrasting actions of four districts reveal a distinct local politics of mosquito control that may have contributed to local-scale geographic differences in WNV incidence. This politics is rooted in political, economic and philosophical differences within and between administrative boundaries. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Respiratory insufficiency correlated strongly with mortality of rodents infected with West Nile virus.

    Directory of Open Access Journals (Sweden)

    John D Morrey

    Full Text Available West Nile virus (WNV disease can be fatal for high-risk patients. Since WNV or its antigens have been identified in multiple anatomical locations of the central nervous system of persons or rodent models, one cannot know where to investigate the actual mechanism of mortality without careful studies in animal models. In this study, depressed respiratory functions measured by plethysmography correlated strongly with mortality. This respiratory distress, as well as reduced oxygen saturation, occurred beginning as early as 4 days before mortality. Affected medullary respiratory control cells may have contributed to the animals' respiratory insufficiency, because WNV antigen staining was present in neurons located in the ventrolateral medulla. Starvation or dehydration would be irrelevant in people, but could cause death in rodents due to lethargy or loss of appetite. Animal experiments were performed to exclude this possibility. Plasma ketones were increased in moribund infected hamsters, but late-stage starvation markers were not apparent. Moreover, daily subcutaneous administration of 5% dextrose in physiological saline solution did not improve survival or other disease signs. Therefore, infected hamsters did not die from starvation or dehydration. No cerebral edema was apparent in WNV- or sham-infected hamsters as determined by comparing wet-to-total weight ratios of brains, or by evaluating blood-brain-barrier permeability using Evans blue dye penetration into brains. Limited vasculitis was present in the right atrium of the heart of infected hamsters, but abnormal electrocardiograms for several days leading up to mortality did not occur. Since respiratory insufficiency was strongly correlated with mortality more than any other pathological parameter, it is the likely cause of death in rodents. These animal data and a poor prognosis for persons with respiratory insufficiency support the hypothesis that neurological lesions affecting respiratory

  20. Phenotypic characterisation of cell populations in the brains of horses experimentally infected with West Nile virus.

    Science.gov (United States)

    Delcambre, G H; Liu, J; Streit, W J; Shaw, G P J; Vallario, K; Herrington, J; Wenzlow, N; Barr, K L; Long, M T

    2017-11-01

    West Nile virus (WNV), a mosquito borne member of the Flaviviridae, is one of the most commonly diagnosed agents of viral encephalitis in horses and people worldwide. A cassette of markers for formalin-fixed paraffin-embedded tissue and an archive of tissues from experimental infections in the horse were used to investigate the equine neuroimmune response to WNV meningoencephalomyelitis to phenotype the early response to WNV infection in the horse. Quantitative analysis using archived tissue from experimentally infected horses. The thalamus and hindbrain from 2 groups of 6 horses were compared and consisted of a culture positive tissues from WNV experimentally horses, in the other, normal horses. Formalin-fixed paraffin-embedded tissue from the thalamus and hindbrain were immunolabeled for microglia, astrocytes, B cells, macrophages/neutrophils, CD3 + T cells. Fresh frozen tissues were immunolabeled for CD4 + and CD8 + T lymphocyte cell markers. Cell counts were obtained using a computer software program. Differences, after meeting assumptions of abnormality, were computed using a general linear model with a Tukey test (Phorses, Iba-1 + microglia, CD3 + T lymphocyte and MAC387 + macrophage staining were significantly increased. The T cell response for the WNV-challenged horses was mixed, composed of CD4 + and CD8 + T lymphocytes. A limited astrocyte response was also observed in WNV-challenged horses, and MAC387 + and B cells were the least abundant cell populations. The results of this study were limited by a single collection time post-infection. Furthermore, a comprehensive analysis of cellular phenotypes is needed for naturally infected horses. Unfortunately, in clinical horses, there is high variability of sampling in terms of days post-infection and tissue handling. The data show that WNV-challenged horses recruit a mixed T cell population at the onset of neurologic disease. © 2017 EVJ Ltd.

  1. An Operational System for Surveillance and Ecological Forecasting of West Nile Virus Outbreaks

    Science.gov (United States)

    Wimberly, M. C.; Davis, J. K.; Vincent, G.; Hess, A.; Hildreth, M. B.

    2017-12-01

    Mosquito-borne disease surveillance has traditionally focused on tracking human cases along with the abundance and infection status of mosquito vectors. For many of these diseases, vector and host population dynamics are also sensitive to climatic factors, including temperature fluctuations and the availability of surface water for mosquito breeding. Thus, there is a potential to strengthen surveillance and predict future outbreaks by monitoring environmental risk factors using broad-scale sensor networks that include earth-observing satellites. The South Dakota Mosquito Information System (SDMIS) project combines entomological surveillance with gridded meteorological data from NASA's North American Land Data Assimilation System (NLDAS) to generate weekly risk maps for West Nile virus (WNV) in the north-central United States. Critical components include a mosquito infection model that smooths the noisy infection rate and compensates for unbalanced sampling, and a human infection model that combines the entomological risk estimates with lagged effects of meteorological variables from the North American Land Data Assimilation System (NLDAS). Two types of forecasts are generated: long-term forecasts of statewide risk extending through the entire WNV season, and short-term forecasts of the geographic pattern of WNV risk in the upcoming week. Model forecasts are connected to public health actions through decision support matrices that link predicted risk levels to a set of phased responses. In 2016, the SDMIS successfully forecast an early start to the WNV season and a large outbreak of WNV cases following several years of low transmission. An evaluation of the 2017 forecasts will also be presented. Our experiences with the SDMIS highlight several important lessons that can inform future efforts at disease early warning. These include the value of integrating climatic models with recent observations of infection, the critical role of automated workflows to facilitate

  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. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Nucleic acid amplification test for detection of west nile virus infection in pakistani blood donors

    International Nuclear Information System (INIS)

    Niazi, S.K.; Alam, M.

    2017-01-01

    Background: The study was planned to determine the presence of West Nile Virus (WNV) infection in Pakistani blood donors, using Nucleic Acid Amplification Test (NAT). Methods: The blood donors for study were selected on the basis of the standard questionnaire and routine screening results. Six donors were pooled using an automated pipettor and NAT for WNV was performed on Roche Cobas s 201 NAT system. The reactive pools were resolved in Individual Donation-NAT (ID-NAT) format and a sample from FFP bags of reactive donations was retrieved. NAT was again performed on retrieved plasma bag (RPB) sample to confirm the reactive donations. The donors were also recalled and interviewed about history of illness related to recent WNV infection. Results: After serological screening of 1929 donors during the study period, 1860 donors were selected for NAT test for WNV detection. The mean age of the donors was 28±8.77 (range: 18–57 years). 1847 (99.3%) donors were male and 13 (0.7%) were female. NAT for WNV identified six initially reactive pools (0.32%). On follow-up testing with RPB samples, 4 donors (0.21%) were found confirmed reactive for WNV RNA (NAT yield of 1 in 465 blood donors). Conclusion: WNV is a threat to safety of blood products in Pakistan. A screening strategy can be implemented after a large-scale study and financial considerations. One of the reduced cost screening strategies is seasonal screening of blood donors for WNV, with pooling of samples. (author)

  4. West Nile virus outbreak in Israel in 2015: phylogenetic and geographic characterization in humans and mosquitoes.

    Science.gov (United States)

    Lustig, Y; Kaufman, Z; Mannasse, B; Koren, R; Katz-Likvornik, S; Orshan, L; Glatman-Freedman, A; Mendelson, E

    2017-12-01

    West Nile Virus (WNV) is endemic in Israel and was responsible for several outbreaks in the past 16 years. The aim of the present study was to investigate the spatial distribution of WNV acute infections from an outbreak that occurred in 2015 in Israel and report the molecular and geographic characterization of WNV isolates from human cases and mosquito pools obtained during this outbreak. Using a geographical layer comprising 51 continuous areas of Israel, the number of WNV infection cases per 100 000 people in each area and the locations of WNV-infected mosquitoes in 2015 were analysed. Sequencing and phylogenetic analyses followed by geographic localization were performed on 13 WNV human isolates and 19 WNV-infected mosquito pools. Substantial geographical variation in the prevalence of acute WNV in patients in Israel was found and an overall correlation with WNV-infected mosquitoes. All human patients sequenced were infected only with the Mediterranean subtype of WNV Lineage 1 and resided primarily in the coastal regions in central Israel. In contrast, mosquitoes were infected with both the Mediterranean and Eastern European subtypes of WNV lineage 1; however, only the Mediterranean subtype was found in mosquitoes from the coastal region in central Israel. These results demonstrate differential geographic dispersion in Israel of the two WNV subtypes and may also point to a differential pattern of human infections. As a geographical bridge between Europe, Asia and Africa, analysis of WNV circulation in humans and mosquitoes in Israel provides information relevant to WNV infections in Eurasia. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  5. West Nile virus in raptors from Virginia during 2003: clinical, diagnostic, and epidemiologic findings.

    Science.gov (United States)

    Joyner, Priscilla H; Kelly, Sean; Shreve, Allison A; Snead, Sarah E; Sleeman, Jonathan M; Pettit, Denise A

    2006-04-01

    Sixty-one birds of prey admitted to The Wildlife Center of Virginia (WCV; Waynesboro, Virginia, USA) from June to November 2003 were tested for West Nile virus (WNV) infection. Choanal and/or cloacal swabs were obtained and submitted to Virginia's Division of Consolidated Laboratory Services (Richmond, Virginia, USA) for analysis with real-time reverse transcriptase polymerase chain reaction (RT-PCR). Forty birds of prey were positive for WNV by RT-PCR. Five avian families and nine species of raptors were represented, with great horned owls (Bubo virginianus) and red-tailed hawks (Buteo jamaicensis) most frequently affected. Presenting clinical signs were consistent with previous reports of WNV infection in raptors; however, these differed between species. Of WNV positive birds, nonspecific signs of illness were the most common clinical findings, particularly in red-tailed hawks; signs included dehydration (n = 20), emaciation (n = 18), and depression (n = 15). Neurologic abnormalities were frequently identified, especially in great horned owls, and included head tremors (n = 17), ataxia (n = 13), head incoordination (n = 7), torticollis (n = 3), nystagmus (n = 3), and head tilt (n = 3). Great horned owls exhibited anemia and leukocytosis with heterophilia, eosinophilia, and monocytosis consistent with chronic inflammation. Red-tailed hawks were anemic with a heterophilic leukocytosis and regenerative left shift. The majority of WNV cases occurred during August and September; there was a marked increase in the number of raptors admitted to WCV during these months followed by a marked decrease during October, November, and December. This pattern differed from mean monthly admissions during the previous 10 years and suggests a negative impact on local raptor populations. The effects of WNV on avian populations are largely unknown; however, because of their ecological importance, further investigation of the effects of WNV on raptor populations is warranted.

  6. 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

  7. Antiviral Properties of the Natural Polyphenols Delphinidin and Epigallocatechin Gallate against the Flaviviruses West Nile Virus, Zika Virus, and Dengue Virus

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    Ángela Vázquez-Calvo

    2017-07-01

    Full Text Available The Flavivirus genus contains important pathogens, such as West Nile virus (WNV, Zika virus (ZIKV, and Dengue virus (DENV, which are enveloped plus-strand RNA viruses transmitted by mosquitoes and constitute a worrisome threat to global human and animal health. Currently no licensed drugs against them are available, being, thus, still necessary the search for effective antiviral molecules. In this line, a novel antiviral approach (economical, simple to use, and environmental friendly is the use of natural compounds. Consequently, we have tested the antiviral potential of different polyphenols present in plants and natural products, such as wine and tea, against WNV, ZIKV, and DENV. So that, we assayed the effect of a panel of structurally related polyphenols [delphinidin (D, cyanidin (Cy, catechin (C, epicatechin (EC, epigallocatechin (EGC, and epigallocatechin gallate (EGCG] on WNV infection, and found that D and EGCG inhibited more effectively the virus production. Further analysis with both compounds indicated that they mainly affected the attachment and entry steps of the virus life cycle. Moreover, D and EGCG showed a direct effect on WNV particles exerting a virucidal effect. We showed a similar inhibition of viral production of these compounds on WNV variants that differed on acidic pH requirements for viral fusion, indicating that their antiviral activity against WNV is produced by a virucidal effect rather than by an inhibition of pH-dependent viral fusion. Both polyphenols also reduced the infectivity of ZIKV and DENV. Therefore, D and EGCG impair the infectivity in cell culture of these three medically relevant flaviviruses.

  8. Diagnosis of West Nile Virus Human Infections: Overview and Proposal of Diagnostic Protocols Considering the Results of External Quality Assessment Studies

    Directory of Open Access Journals (Sweden)

    Ana Vázquez

    2013-09-01

    Full Text Available West Nile virus, genus Flavivirus, is transmitted between birds and occasionally other animals by ornithophilic mosquitoes. This virus also infects humans causing asymptomatic infections in about 85% of cases and <1% of clinical cases progress to severe neuroinvasive disease. The virus also presents a threat since most infections remain unapparent. However, the virus contained in blood and organs from asymptomatically infected donors can be transmitted to recipients of these infectious tissues. This paper reviews the presently available methods to achieve the laboratory diagnosis of West Nile virus infections in humans, discussing the most prominent advantages and disadvantages of each in light of the results obtained during four different External Quality Assessment studies carried out by the European Network for ‘Imported’ Viral Diseases (ENIVD.

  9. Chimeric vaccine composed of viral peptide and mammalian heat-shock protein 60 peptide protects against West Nile virus challenge.

    Science.gov (United States)

    Gershoni-Yahalom, Orly; Landes, Shimon; Kleiman-Shoval, Smadar; Ben-Nathan, David; Kam, Michal; Lachmi, Bat-El; Khinich, Yevgeny; Simanov, Michael; Samina, Itzhak; Eitan, Anat; Cohen, Irun R; Rager-Zisman, Bracha; Porgador, Angel

    2010-08-01

    The protective efficacy and immunogenicity of a chimeric peptide against West Nile virus (WNV) was evaluated. This virus is the aetiological agent of West Nile fever, which has recently emerged in the western hemisphere. The rapid spread of WNV throughout North America, as well as the constantly changing epidemiology and transmission of the virus by blood transfusion and transplantation, have raised major public-health concerns. Currently, there are no effective treatments for WNV or vaccine for human use. We previously identified a novel, continuous B-cell epitope from domain III of the WNV envelope protein, termed Ep15. To test whether this epitope can protect against WNV infection, we synthesized a linear chimeric peptide composed of Ep15 and the heat-shock protein 60 peptide, p458. The p458 peptide is an effective carrier peptide for subunit vaccines against other infectious agents. We now report that mice immunized with the chimeric peptide, p458-Ep15, were resistant to lethal challenges with three different WNV strains. Moreover, their brains were free of viral genome and infectious virus. Mice immunized with Ep15 alone or with p431-Ep15, a control conjugate, were not protected. The chimeric p458-Ep15 peptide induced WNV-specific immunoglobulin G antibodies that neutralized the virus and induced the secretion of interferon-gammain vitro. Challenge of chimeric peptide-immunized mice considerably enhanced WNV-specific neutralizing antibodies. We conclude that this chimeric peptide can be used for formulation of a human vaccine against WNV.

  10. High Prevalence of West Nile Virus in Domestic Birds and Detection in 2 New Mosquito Species in Madagascar.

    Science.gov (United States)

    Maquart, Marianne; Boyer, Sébastien; Rakotoharinome, Vincent Michel; Ravaomanana, Julie; Tantely, Michael Luciano; Heraud, Jean-Michel; Cardinale, Eric

    2016-01-01

    West Nile virus is an arthropod-borne zoonosis transmitted by a large number of mosquito species, and birds play a key role as reservoir of the virus. Its distribution is largely widespread over Africa, Asia, the Americas and Europe. Since 1978, it has frequently been reported in Madagascar. Studies described a high seroprevalence level of the virus in humans in different areas of the island and a human fatal case of WNV infection was reported in 2011. Despite these reports, the epidemiology of WNV in Madagascar, in particular, viral circulation remains unclear. To explore the transmission of WNV in two rural human populations of Madagascar, we investigated local mosquitoes and poultry for evidence of current infections, and determined seroprevalence of candidate sentinel species among the local poultry. These 2 areas are close to lakes where domestic birds, migratory wild birds and humans coexist. Serological analysis revealed WNV antibodies in domestic birds (duck, chicken, goose, turkey and guinea fowl) sampled in both districts (Antsalova 29.4% and Mitsinjo 16.7%). West Nile virus nucleic acid was detected in one chicken and in 8 pools of mosquitoes including 2 mosquito species (Aedeomyia madagascarica and Anopheles pauliani) that have not been previously described as candidate vectors for WNV. Molecular analysis of WNV isolates showed that all viruses detected were part of the lineage 2 that is mainly distributed in Africa, and were most closely matched by the previous Malagasy strains isolated in 1988. Our study showed that WNV circulates in Madagascar amongst domestic birds and mosquitoes, and highlights the utility of poultry as a surveillance tool to detect WNV transmission in a peri-domestic setting.

  11. Monitoring of West Nile virus, Usutu virus and Meaban virus in waterfowl used as decoys and wild raptors in southern Spain.

    Science.gov (United States)

    Jurado-Tarifa, E; Napp, S; Lecollinet, S; Arenas, A; Beck, C; Cerdà-Cuéllar, M; Fernández-Morente, M; García-Bocanegra, I

    2016-12-01

    In the last decade, the number of emerging flaviviruses described worldwide has increased considerably, with wild birds acting as the main reservoir hosts of these viruses. We carried out an epidemiological survey to determine the seroprevalence of antigenically related flaviviruses, particularly West Nile virus (WNV), Usutu virus (USUV) and Meaban virus (MBV), in waterfowl used as decoys and wild raptors in Andalusia (southern Spain), the region considered to have the highest risk of flaviviruses circulation in Spain. The overall flaviviruses seroprevalence according to bELISA was 13.0% in both in decoys (n=1052) and wild raptors (n=123). Specific antibodies against WNV, USUV and MBV were confirmed by micro virus neutralization tests in 12, 38 and 4 of the seropositive decoys, respectively. This is the first study on WNV and USUV infections in decoys and the first report of MBV infections in waterfowl and raptors. Moreover we report the first description of WNV infections in short-toed snake eagle (Circaetus gallicus) and Montagu's harrier (Circus pygargus). The seropositivity obtained indicates widespread but not homogeneous distribution of WNV and USUV in Andalusia. The results also confirm endemic circulation of WNV, USUV and MBV in both decoys and wild raptors in southern Spain. Our results highlight the need to implement surveillance and control programs not only for WNV but also for other related flaviviruses. Further research is needed to determine the eco-epidemiological role that waterfowl and wild raptors play in the transmission of emerging flaviviruses, especially in decoys, given their close interactions with humans. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. 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

    2016-08-04

    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. This article is copyright of The Authors, 2016.

  13. West Nile virus lineage 2 isolated from Culex modestus mosquitoes in the Czech Republic, 2013: expansion of the European WNV endemic area to the North?

    Czech Academy of Sciences Publication Activity Database

    Rudolf, Ivo; Bakonyi, T.; Šebesta, Oldřich; Mendel, Jan; Peško, Juraj; Betášová, Lenka; Blažejová, Hana; Venclíková, Kristýna; Straková, Petra; Nowotny, N.; Hubálek, Zdeněk

    2014-01-01

    Roč. 19, č. 31 (2014), pii=20867 ISSN 1560-7917 EU Projects: European Commission(XE) 261504 - EDENEXT Institutional support: RVO:68081766 Keywords : West Nile virus * mosquitoes * Czech Republic Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 5.722, year: 2014 http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20867

  14. A VLP-based vaccine targeting domain III of the West Nile virus e protein protects from lethal infection in mice

    NARCIS (Netherlands)

    G. Spohn (Gunther); G.T. Jennings (Gary); B.E.E. Martina (Byron); I. Keller (Iris); M. Beck (Markus); P. Pumpens (Paul); A.D.M.E. Osterhaus (Albert); M.F. Bachmann (Martin)

    2010-01-01

    textabstractBackground. Since its first appearance in the USA in 1999, West Nile virus (WNV) has spread in the Western hemisphere and continues to represent an important public health concern. In the absence of effective treatment, there is a medical need for the development of a safe and efficient

  15. 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

  16. 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.

  17. 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

    OpenAIRE

    Hua, Rong-Hong; Chen, Na-Sha; Qin, Cheng-Feng; Deng, Yong-Qiang; Ge, Jin-Ying; Wang, Xi-Jun; Qiao, Zu-Jian; Chen, Wei-Ye; Wen, Zhi-Yuan; Liu, Wen-Xin; Hu, Sen; Bu, Zhi-Gao

    2010-01-01

    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 P...

  18. 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

  19. The Immune Responses of the Animal Hosts of West Nile Virus: A Comparison of Insects, Birds, and Mammals

    Directory of Open Access Journals (Sweden)

    Laura R. H. Ahlers

    2018-04-01

    Full Text Available Vector-borne diseases, including arboviruses, pose a serious threat to public health worldwide. Arboviruses of the flavivirus genus, such as Zika virus (ZIKV, dengue virus, yellow fever virus (YFV, and West Nile virus (WNV, are transmitted to humans from insect vectors and can cause serious disease. In 2017, over 2,000 reported cases of WNV virus infection occurred in the United States, with two-thirds of cases classified as neuroinvasive. WNV transmission cycles through two different animal populations: birds and mosquitoes. Mammals, particularly humans and horses, can become infected through mosquito bites and represent dead-end hosts of WNV infection. Because WNV can infect diverse species, research on this arbovirus has investigated the host response in mosquitoes, birds, humans, and horses. With the growing geographical range of the WNV mosquito vector and increased human exposure, improved surveillance and treatment of the infection will enhance public health in areas where WNV is endemic. In this review, we survey the bionomics of mosquito species involved in Nearctic WNV transmission. Subsequently, we describe the known immune response pathways that counter WNV infection in insects, birds, and mammals, as well as the mechanisms known to curb viral infection. Moreover, we discuss the bacterium Wolbachia and its involvement in reducing flavivirus titer in insects. Finally, we highlight the similarities of the known immune pathways and identify potential targets for future studies aimed at improving antiviral therapeutic and vaccination design.

  20. Global research trends in West Nile virus from 1943 to 2016: a bibliometric analysis.

    Science.gov (United States)

    Al-Jabi, Samah W

    2017-08-03

    West Nile virus (WNV) is an emerging infectious disease which is most commonly transmitted to humans through mosquito, and is considered a major public-health problem worldwide. The aim of the current study is to bibliometrically analyze the quantity and quality of publications indexed in Scopus from different countries to reveal the characteristics of global research output regarding WNV. This study is a bibliometric analysis based on the Scopus database. This study focused on identifying WNV publication trends with regard to publication year, publication type, prolific countries, language of publication, as well as, prolific journals, citations, and collaboration patterns. A total of 4729 publications were considered in this study, which were published between 1943 and 2016. The annual quantity of literature published before 2000 followed a low rate of research growth; while the quantity of publications after 2000 were published in a stage of rapid development. The country with the greatest number of publications in WNV research field was the USA with 2304 (48.7%) publications, followed by France with 224 (4.7%) publications, and Canada with 222 (4.7%) publications. Contributions from low- and middle-income countries (LMIC) were considerably small, that is, (n = 519 publications; 11%). All publications related to WNV achieved h-index of 140 and were cited 124,222 times. The median [interquartile range] number of citations per article thus amounts to 9 [2-28]. The USA had the highest h-index of 131. Emerging Infectious Diseases is the most productive journal with 227 articles, followed by Journal of Virology with 162 publications. The result designated that Centers for Disease Control and Prevention was ranked the first in terms of publication output, followed by National Center for Emerging and Zoonotic Infectious Diseases. There is an obvious trend of WNV research after 2000, and countries with high income have more contributions in WNV research field. The

  1. 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

  2. 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.

  3. Characterization of a 105-kDa plasma membrane associated glycoprotein that is involved in West Nile virus binding and infection

    International Nuclear Information System (INIS)

    Chu, J.J.H.; Ng, M.L.

    2003-01-01

    This study attempts to isolate and characterize West Nile virus-binding molecules on the plasma membrane of Vero and murine neuroblastoma cells that is responsible for virus entry. Pretreatment of Vero cells with proteases, glycosidases (endoglycosidase H, α-mannosidase), and sodium periodate strongly inhibited West Nile virus infection, whereas treatments with phospholipases and heparinases had no effect. The virus overlay protein blot detected a 105-kDa molecule on the plasma membrane extract of Vero and murine neuroblastoma cells that bind to WN virus. Treatment of the 105-kDa molecules with β-mercaptoethanol resulted in the virus binding to a series of lower molecular weight bands ranging from 30 to 40 kDa. The disruption of disulfide-linked subunits did not affect virus binding. N-linked sugars with mannose residues on the 105-kDa membrane proteins were found to be important in virus binding. Specific antibodies against the 105-kDa glycoprotein were highly effective in blocking virus entry. These results strongly supported the possibility that the 105-kDa protease-sensitive glycoprotein with complex N-linked sugars could be the putative receptor for WN virus

  4. Surveillance for West Nile Virus in Wild Birds from Northern Europe

    Czech Academy of Sciences Publication Activity Database

    Jourdain, E.; Olsen, B.; Lundkvist, A.; Hubálek, Zdeněk; Šikutová, Silvie; Waldenström, J.; Karlsson, M.; Wahlström, M.; Jozan, M.; Falk, K. I.

    2011-01-01

    Roč. 11, č. 1 (2011), s. 77-79 ISSN 1530-3667 Institutional research plan: CEZ:AV0Z60930519 Keywords : Antibodies * Migratory birds * Sweden * West Nile Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology Impact factor: 2.437, year: 2011

  5. 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

  6. West Nile Virus Infection in American Singer Canaries: An Experimental Model in a Highly Susceptible Avian Species.

    Science.gov (United States)

    Hofmeister, Erik K; Lund, Melissa; Shearn Bochsler, Valerie

    2018-01-01

    This study investigated the susceptibility of American singer canaries ( Serinus canaria) to West Nile virus (WNV) infection. Adult canaries were inoculated with 10 5 , 10 2 , and 10 1 plaque forming units (PFU) of WNV. All birds became infected and mortality occurred by 5 days postinoculation. The load of viral RNA as determined by RT-qPCR was dose dependent, and was higher at all doses than the level of viral RNA detected in American crows ( Corvus brachyrhynchos) challenged with 10 5 PFU of WNV. In a subset of birds, viremia was detected by virus isolation; canaries inoculated with 10 1 PFU of WNV developed viremia exceeding 10 10 PFU/mL serum, a log higher than American crows inoculated with 10 5 PFU of virus. In canaries euthanized at 3 days postinoculation, WNV was isolated at >10 7 PFU of virus/100 mg of lung, liver, heart, spleen, and kidney tissues. Pallor of the liver and splenomegaly were the most common macroscopic observations and histologic lesions were most severe in liver, spleen, and kidney, particularly in canaries challenged with 10 2 and 10 1 PFU. Immunoreactivity to WNV was pronounced in the liver and spleen. IgG antibodies to WNV were detected in serum by enzyme immunoassay in 11 of 21 (52%) challenged canaries and, in 4 of 5 (20%) of these sera, neutralization antibodies were detected at a titer ≥ 1:20. American singer canaries provide a useful model as this bird species is highly susceptible to WNV infection.

  7. 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.

  8. 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

  9. Infodemiological data of West-Nile virus disease in Italy in the study period 2004–2015

    Directory of Open Access Journals (Sweden)

    Nicola Luigi Bragazzi

    2016-12-01

    Full Text Available Google Trends (GT was mined from 2004 to 2015, searching for West-Nile virus disease (WNVD in Italy. GT-generated data were modeled as a time series and were analyzed using classical time series analyses. In particular, correlation between GT-based Relative Search Volumes (RSVs related to WNVD and “real-world” epidemiological cases in the same study period resulted r=0.76 (p<0.0001 on a monthly basis and r=0.80 (p<0.0001 on a yearly basis. The partial autocorrelation analysis and the spectral analysis confirmed that a 1-year regular pattern could be detected. Correlation between GT-based RSVs related to WNVD yielded a r=0.54 (p<0.05 on a regional basis. Summarizing, GT-generated data concerning WNVD well correlated with epidemiology and could be exploited for complementing traditional surveillance.

  10. A mutation in the envelope protein fusion loop attenuates mouse neuroinvasiveness of the NY99 strain of West Nile virus

    International Nuclear Information System (INIS)

    Zhang Shuliu; Li Li; Woodson, Sara E.; Huang, Claire Y.-H.; Kinney, Richard M.; Barrett, Alan D.T.; Beasley, David W.C.

    2006-01-01

    Substitutions were engineered individually and in combinations at the fusion loop, receptor-binding domain and a stem-helix structure of the envelope protein of a West Nile virus strain, NY99, and their effects on mouse virulence and presentation of epitopes recognized by monoclonal antibodies (MAbs) were assessed. A single substitution within the fusion loop (L107F) attenuated mouse neuroinvasiveness of NY99. No substitutions attenuated NY99 neurovirulence. The L107F mutation also abolished binding of a non-neutralizing MAb, 3D9, whose epitope had not been previously identified. MAb 3D9 was subsequently shown to be broadly cross-reactive with other flaviviruses, consistent with binding near the highly conserved fusion loop

  11. Sentinel pigeon surveillance for West Nile virus by using lard-can traps at differing elevations and canopy cover classes.

    Science.gov (United States)

    Deegan, Carrie S; Burns, Joseph E; Huguenin, Michael; Steinhaus, Eliza Y; Panella, Nicholas A; Beckett, Susan; Komar, Nicholas

    2005-11-01

    Sentinel pigeons, Columba livia, were installed in lard-can traps at heights of 1.5 m and 7.6-9.1 m within differing canopy cover classes in New York City. Adult mosquitoes were collected weekly from July to October 2002, as were serum samples from each pigeon. Culex pipiens L. and Culex restuans Theobald comprised 97% of mosquitoes collected and were most numerous in canopy-level, forested traps. The West Nile virus (family Flaviviridae, genus Flavivirus, WNV) seroconversion rate was significantly greater for pigeons in canopy-level traps, although seroconversions occurred concurrently with human cases in the city and were of little prognostic value to public health agencies. Our results indicate that sentinel pigeons were most effective for monitoring enzootic transmission of WNV when placed in single-sentinel caging 7.6-9.1 m above ground level.

  12. 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.

  13. 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

  14. 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.

  15. Búsqueda de flavivirus en mosquitos de humedales españoles: análisis moleculares del virus west nile y otros flavivirus

    OpenAIRE

    Vázquez González, Ana

    2011-01-01

    Teniendo en cuenta la importancia de los flavivirus en salud humana, la gran actividad y expansión del virus West Nile en los últimos años y los antecedentes serológicos que evidencian la presencia de estos virus en nuestro país, esta tesis doctoral se ha basado en el estudio de la presencia de estos virus, en su caracterización molecular y filogenética y en el desarrollo de nueva metodología para su diagnóstico. Por ello nos planteamos tres objetivos principales. En primer lug...

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

    Centers for Disease Control (CDC) Podcasts

    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).

  17. A Thiopurine Drug Inhibits West Nile Virus Production in Cell Culture, but Not in Mice

    OpenAIRE

    Lim, Pei-Yin; Keating, Julie A.; Hoover, Spencer; Striker, Rob; Bernard, Kristen A.

    2011-01-01

    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 dive...

  18. Epidemic Spread of Usutu Virus in Southwest Germany in 2011 to 2013 and Monitoring of Wild Birds for Usutu and West Nile Viruses.

    Science.gov (United States)

    Ziegler, Ute; Jöst, Hanna; Müller, Kerstin; Fischer, Dominik; Rinder, Monika; Tietze, Dieter Thomas; Danner, Klaus-Jürgen; Becker, Norbert; Skuballa, Jasmin; Hamann, Hans-Peter; Bosch, Stefan; Fast, Christine; Eiden, Martin; Schmidt-Chanasit, Jonas; Groschup, Martin H

    2015-08-01

    Mosquito-borne viruses are becoming an increasing threat for Europe. One of these viruses is Usutu virus (USUV), a single-stranded RNA virus belonging to the Japanese encephalitis virus group within the family Flaviviridae. Since the occurrence of USUV among wild birds in June, 2011, infected Blackbirds (Turdus merula) have frequently been found dead in southwest Germany, cumulating in a massive die-off. Moreover, other bird species (Strigiformes) in this region have been affected. In a first study, 209 of over 600 dead birds (wild birds and birds kept in aviaries) collected from 2011 to 2013 carried USUV, more than 88% of them Blackbirds. USUV had already been detected in 2010, one year before the epizooty, in a mosquito-based surveillance program in Germany. The main epidemic area of the USUV outbreak in wild birds in southwest Germany has been similar for the last three years. In a second study during 2011 to 2013, 902 live migratory and resident birds (representing 87 bird species belonging to 14 bird orders) from four different sampling sites were bled and tested serologically and by qPCR for West Nile virus (WNV) and USUV infections. No USUV or WNV genomes were detected. Some migratory birds (mainly long-distance migrants and some partial migrants) carried neutralizing antibodies against WNV as discriminated by USUV and WNV cross-neutralization tests. Only few resident birds showed relevant USUV-specific neutralizing antibodies. The occurrence of USUV in the Upper Rhine valley area of southwest Germany is a proof of principle for the incursion and spread of other arthropod-borne (arbo)-viruses along these routes. Therefore, monitoring studies in birds and mosquitoes for the presence of arboviruses in these areas are indispensable.

  19. ¿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.

  20. West Nile virus infection in American singer canaries: An experimental model in a highly susceptible avian species

    Science.gov (United States)

    Hofmeister, Erik K.; Lund, Melissa; Shearn-Bochsler, Valerie I.

    2018-01-01

    This study investigated the susceptibility of American singer canaries (Serinus canaria) to West Nile virus (WNV) infection. Adult canaries were inoculated with 105, 102, and 101plaque forming units (PFU) of WNV. All birds became infected and mortality occurred by 5 days postinoculation. The load of viral RNA as determined by RT-qPCR was dose dependent, and was higher at all doses than the level of viral RNA detected in American crows (Corvus brachyrhynchos) challenged with 105 PFU of WNV. In a subset of birds, viremia was detected by virus isolation; canaries inoculated with 101 PFU of WNV developed viremia exceeding 1010 PFU/mL serum, a log higher than American crows inoculated with 105 PFU of virus. In canaries euthanized at 3 days postinoculation, WNV was isolated at >107 PFU of virus/100 mg of lung, liver, heart, spleen, and kidney tissues. Pallor of the liver and splenomegaly were the most common macroscopic observations and histologic lesions were most severe in liver, spleen, and kidney, particularly in canaries challenged with 102 and 101 PFU. Immunoreactivity to WNV was pronounced in the liver and spleen. IgG antibodies to WNV were detected in serum by enzyme immunoassay in 11 of 21 (52%) challenged canaries and, in 4 of 5 (20%) of these sera, neutralization antibodies were detected at a titer ≥ 1:20. American singer canaries provide a useful model as this bird species is highly susceptible to WNV infection.

  1. West Nile Virus: High Transmission Rate in North-Western European Mosquitoes Indicates Its Epidemic Potential and Warrants Increased Surveillance.

    Directory of Open Access Journals (Sweden)

    Jelke J Fros

    Full Text Available West Nile virus (WNV is a highly pathogenic flavivirus transmitted by Culex spp. mosquitoes. In North America (NA, lineage 1 WNV caused the largest outbreak of neuroinvasive disease to date, while a novel pathogenic lineage 2 strain circulates in southern Europe. To estimate WNV lineage 2 epidemic potential it is paramount to know if mosquitoes from currently WNV-free areas can support further spread of this epidemic.We assessed WNV vector competence of Culex pipiens mosquitoes originating from north-western Europe (NWE in direct comparison with those from NA. We exposed mosquitoes to infectious blood meals of lineage 1 or 2 WNV and determined the infection and transmission rates. We explored reasons for vector competence differences by comparing intrathoracic injection versus blood meal infection, and we investigated the influence of temperature. We found that NWE mosquitoes are highly competent for both WNV lineages, with transmission rates up to 25%. Compared to NA mosquitoes, transmission rates for lineage 2 WNV were significantly elevated in NWE mosquitoes due to better virus dissemination from the midgut and a shorter extrinsic incubation time. WNV infection rates further increased with temperature increase.Our study provides experimental evidence to indicate markedly different risk levels between both continents for lineage 2 WNV transmission and suggests a degree of genotype-genotype specificity in the interaction between virus and vector. Our experiments with varying temperatures explain the current localized WNV activity in southern Europe, yet imply further epidemic spread throughout NWE during periods with favourable climatic conditions. This emphasizes the need for intensified surveillance of virus activity in current WNV disease-free regions and warrants increased awareness in clinics throughout Europe.

  2. West nile virus prevalence across landscapes is mediated by local effects of agriculture on vector and host communities.

    Science.gov (United States)

    Crowder, David W; Dykstra, Elizabeth A; Brauner, Jo Marie; Duffy, Anne; Reed, Caitlin; Martin, Emily; Peterson, Wade; Carrière, Yves; Dutilleul, Pierre; Owen, Jeb P

    2013-01-01

    Arthropod-borne viruses (arboviruses) threaten the health of humans, livestock, and wildlife. West Nile virus (WNV), the world's most widespread arbovirus, invaded the United States in 1999 and rapidly spread across the county. Although the ecology of vectors and hosts are key determinants of WNV prevalence across landscapes, the factors shaping local vector and host populations remain unclear. Here, we used spatially-explicit models to evaluate how three land-use types (orchards, vegetable/forage crops, natural) and two climatic variables (temperature, precipitation) influence the prevalence of WNV infections and vector/host distributions at landscape and local spatial scales. Across landscapes, we show that orchard habitats were associated with greater prevalence of WNV infections in reservoirs (birds) and incidental hosts (horses), while increased precipitation was associated with fewer infections. At local scales, orchard habitats increased the prevalence of WNV infections in vectors (mosquitoes) and the abundance of mosquitoes and two key reservoir species, the American robin and the house sparrow. Thus, orchard habitats benefitted WNV vectors and reservoir hosts locally, creating focal points for the transmission of WNV at landscape scales in the presence of suitable climatic conditions.

  3. Effects of West Nile virus dose and extrinsic incubation temperature on temporal progression of vector competence in Culex pipiens quinquefasciatus.

    Science.gov (United States)

    Anderson, Sheri L; Richards, Stephanie L; Tabachnick, Walter J; Smartt, Chelsea T

    2010-03-01

    Culex pipiens quinquefasciatus were fed blood containing either 7.0 +/- 0.1 logs plaque-forming units (pfu)/ml (high dose) or 5.9 +/- 0.1 logs pfu/ml (low dose) of West Nile virus and held at extrinsic incubation temperatures (EIT) of 28 degrees C or 25 degrees C. Approximately 20 mosquitoes per dose were collected after incubation periods (IP) of 4, 6, 8, and 12 days postinfection (dpi). Infection rates were influenced by EIT and virus dose but not by IP. Body titer was significantly higher for mosquitoes fed the high dose and held at 28 degrees C at the later IPs (6, 8, and 12 dpi). However, leg titer was significantly higher for mosquitoes at the later IPs but did not differ between EITs or doses. Because infection rates varied with EIT and dose, there is likely a midgut infection barrier influenced by these factors that is not influenced by IP. Dissemination rates were influenced by all 3 factors consistent with the presence of a midgut escape barrier. Dissemination rate, body titer, and leg titer were dependent on IP, indicating the need to investigate multiple time points in vector competence studies to elucidate critical events in infection and dissemination.

  4. Impact of West Nile virus dose and incubation period on vector competence of Culex nigripalpus (Diptera: Culicidae).

    Science.gov (United States)

    Richards, Stephanie L; Anderson, Sheri L; Lord, Cynthia C; Tabachnick, Walter J

    2011-11-01

    Female Culex nigripalpus were fed blood containing a low dose (6.3±0.01 logs plaque-forming units (PFU)/mL) or high dose (7.3±0.1 logs PFU/mL) of West Nile virus (WNV) and maintained at 28°C for incubation periods (IPs) of 6 or 12 days. Vector competence was measured using rates of infection (% with WNV-positive bodies), dissemination (% infected with WNV-positive legs), and transmission (% infected with WNV-positive saliva). Infection rates were not influenced by dose or IP. Dissemination rates were significantly higher at the high dose, and this was dependent on IP. Despite 100% infection and 90% dissemination in the most permissive treatment of high dose and 12 days, only 11% transmission was observed. Virus titers in body and leg tissues were significantly lower at the low dose and the titers were not influenced by IP. We show that not all mosquitoes with infections and/or disseminated infections transmit WNV under the conditions of this test. Therefore, characterizing the transmission ability of a vector population using infection or dissemination as indicators of transmission may provide inaccurate information. The complex relationships between infection, dissemination, and transmission must be evaluated under a variety of biological and environmental conditions to begin to assess the epidemiological risk of natural mosquito populations.

  5. Evolutionary relationship between Old World West Nile virus strains Evidence for viral gene flow between africa, the middle east, and europe

    International Nuclear Information System (INIS)

    Charrel, R.N.; Brault, A.C.; Gallian, P.; Lemasson, J.-J.; Murgue, B.; Murri, S.; Pastorino, B.; Zeller, H.; Chesse, R. de; Micco, P. de; Lamballerie, X. de

    2003-01-01

    Little is known about the genetic relationships between European and other Old-World strains of West Nile virus (WNV) and persistence of WNV North of Mediterranean. We characterized the complete genomes of three WNV strains from France (horse-2000), Tunisia (human-1997) and Kenya (mosquito-1998), and the envelope, NS3 and NS5 genes of the Koutango virus. Phylogenetic analyses including all available full-length sequences showed that: (1) Koutango virus is a distant variant of WNV; (2) the three characterized strains belong to lineage 1, clade 1a; (3) the Tunisian strain roots the lineage of viruses introduced in North America. We established that currently available partial envelope sequences do not generate reliable phylogenies. Accordingly, establishing a large WNV sequence database is pivotal for the understanding of spatial and temporal epidemiology of this virus. For rapid completion of that purpose, colinearized E-NS3-NS5 gene sequences were shown to constitute a valuable surrogate for complete sequences

  6. 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)

    Ambrose, R.L.; Mackenzie, J.M.

    2015-01-01

    The West Nile virus strain Kunjin virus (WNV KUN ) NS4A protein is a multifunctional protein involved in many aspects of the virus life-cycle and is a major component of the WNV 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 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

  7. A single amino acid substitution in the core protein of West Nile virus increases resistance to acidotropic compounds.

    Directory of Open Access Journals (Sweden)

    Miguel A Martín-Acebes

    Full Text Available West Nile virus (WNV is a worldwide distributed mosquito-borne flavivirus that naturally cycles between birds and mosquitoes, although it can infect multiple vertebrate hosts including horses and humans. This virus is responsible for recurrent epidemics of febrile illness and encephalitis, and has recently become a global concern. WNV requires to transit through intracellular acidic compartments at two different steps to complete its infectious cycle. These include fusion between the viral envelope and the membrane of endosomes during viral entry, and virus maturation in the trans-Golgi network. In this study, we followed a genetic approach to study the connections between viral components and acidic pH. A WNV mutant with increased resistance to the acidotropic compound NH4Cl, which blocks organelle acidification and inhibits WNV infection, was selected. Nucleotide sequencing revealed that this mutant displayed a single amino acid substitution (Lys 3 to Glu on the highly basic internal capsid or core (C protein. The functional role of this replacement was confirmed by its introduction into a WNV infectious clone. This single amino acid substitution also increased resistance to other acidification inhibitor (concanamycin A and induced a reduction of the neurovirulence in mice. Interestingly, a naturally occurring accompanying mutation found on prM protein abolished the resistant phenotype, supporting the idea of a genetic crosstalk between the internal C protein and the external glycoproteins of the virion. The findings here reported unveil a non-previously assessed connection between the C viral protein and the acidic pH necessary for entry and proper exit of flaviviruses.

  8. A single amino acid substitution in the core protein of West Nile virus increases resistance to acidotropic compounds.

    Science.gov (United States)

    Martín-Acebes, Miguel A; Blázquez, Ana-Belén; de Oya, Nereida Jiménez; Escribano-Romero, Estela; Shi, Pei-Yong; Saiz, Juan-Carlos

    2013-01-01

    West Nile virus (WNV) is a worldwide distributed mosquito-borne flavivirus that naturally cycles between birds and mosquitoes, although it can infect multiple vertebrate hosts including horses and humans. This virus is responsible for recurrent epidemics of febrile illness and encephalitis, and has recently become a global concern. WNV requires to transit through intracellular acidic compartments at two different steps to complete its infectious cycle. These include fusion between the viral envelope and the membrane of endosomes during viral entry, and virus maturation in the trans-Golgi network. In this study, we followed a genetic approach to study the connections between viral components and acidic pH. A WNV mutant with increased resistance to the acidotropic compound NH4Cl, which blocks organelle acidification and inhibits WNV infection, was selected. Nucleotide sequencing revealed that this mutant displayed a single amino acid substitution (Lys 3 to Glu) on the highly basic internal capsid or core (C) protein. The functional role of this replacement was confirmed by its introduction into a WNV infectious clone. This single amino acid substitution also increased resistance to other acidification inhibitor (concanamycin A) and induced a reduction of the neurovirulence in mice. Interestingly, a naturally occurring accompanying mutation found on prM protein abolished the resistant phenotype, supporting the idea of a genetic crosstalk between the internal C protein and the external glycoproteins of the virion. The findings here reported unveil a non-previously assessed connection between the C viral protein and the acidic pH necessary for entry and proper exit of flaviviruses.

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

    Directory of Open Access Journals (Sweden)

    Diana Thomas

    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.

  10. MicroRNA reduction of neuronal West Nile virus replication attenuates and affords a protective immune response in mice.

    Science.gov (United States)

    Brostoff, Terza; Pesavento, Patricia A; Barker, Christopher M; Kenney, Joan L; Dietrich, Elizabeth A; Duggal, Nisha K; Bosco-Lauth, Angela M; Brault, Aaron C

    2016-10-17

    West Nile virus (WNV) is an important agent of human encephalitis that has quickly become endemic across much of the United States since its identification in North America in 1999. While the majority (∼75%) of infections are subclinical, neurologic disease can occur in a subset of cases, with outcomes including permanent neurologic damage and death. Currently, there are no WNV vaccines approved for use in humans. This study introduces a novel vaccine platform for WNV to reduce viral replication in the central nervous system while maintaining peripheral replication to elicit strong neutralizing antibody titers. Vaccine candidates were engineered to incorporate microRNA (miRNA) target sequences for a cognate miRNA expressed only in neurons, allowing the host miRNAs to target viral transcription through endogenous RNA silencing. To maintain stability, these targets were incorporated in multiple locations within the 3'-untranslated region, flanking sequences essential for viral replication without affecting the viral open reading frame. All candidates replicated comparably to wild type WNV in vitro within cells that did not express the cognate miRNA. Insertional control viruses were also capable of neuroinvasion and neurovirulence in vivo in CD-1 mice. Vaccine viruses were safe at all doses tested and did not demonstrate mutations associated with a reversion to virulence when serially passaged in mice. All vaccine constructs were protective from lethal challenge in mice, producing 93-100% protection at the highest dose tested. Overall, this is a safe and effective attenuation strategy with broad potential application for vaccine development. Published by Elsevier Ltd.

  11. Virus Mayaro: un arbovirus reemergente en Venezuela y Latinoamérica

    Directory of Open Access Journals (Sweden)

    Manuel Muñoz

    2012-06-01

    Full Text Available El virus Mayaro produce una enfermedad de síntomas inespecíficos y subletales, frecuentemente confundida con dengue, con síntomas de artralgias que pueden generar incapacidad laboral. Los brotes han sido esporádicos y localizados en la región selvática de la Panamazonia, posterior a su primer aislamiento en 1954 (Trinidad y Tobago. La información en la literatura científica es escasa, diversa y dispersa. El virus Mayaro es un alfavirus filogenéticamente relacionado con el complejo del virus Semliki Forest (SFV; con el UNA, son los únicos virus de dicho complejo aislados en el Nuevo mundo. Está conformado por ARN de cadena simple de carga positiva, con longitud de 12 kb con la región 42S y 26S, que codifican para proteínas no estructurales y estructurales. El virus Mayaro presenta gran adaptabilidad para la infección en vertebrados y especificidad hacia la familia Culicidae (mosquitos como vectores u hospedadores invertebrados. Los factores de riesgo están asociados a zonas boscosas de la región septentrional de Suramérica y en temporada lluviosa. Se conocen dos genotipos, L (Belterra, Brasil y D (distribución panamazónica. El ciclo enzoótico es similar al de la fiebre amarilla, que involucra a mosquitos del género Haemagogus y, como reservorios, a monos, sin descartar la participación de vectores secundarios y otros hospedadores que pudieran participar en la diseminación del virus. El humano puede presentar viremia elevada y se ha demostrado la transmisión experimental en Aedes aegypti, Ae. scapularis y Ae. albopictus, constituyendo un riesgo para la salud pública en centros urbanos y zonas rurales cercanas a focos de virus Mayaro.   doi: http://dx.doi.org/10.7705/biomedica.v32i2.647

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

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    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.

  13. Potential for Co-Infection of a Mosquito-Specific Flavivirus, Nhumirim Virus, to Block West Nile Virus Transmission in Mosquitoes

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    Silvina Goenaga

    2015-11-01

    Full Text Available Nhumirim virus (NHUV is an insect-specific virus that phylogenetically affiliates with dual-host mosquito-borne flaviviruses. Previous in vitro co-infection experiments demonstrated prior or concurrent infection of Aedes albopictus C6/36 mosquito cells with NHUV resulted in a 10,000-fold reduction in viral production of West Nile virus (WNV. This interference between WNV and NHUV was observed herein in an additional Ae. albopictus mosquito cell line, C7-10. A WNV 2K peptide (V9M mutant capable of superinfection with a pre-established WNV infection demonstrated a comparable level of interference from NHUV as the parental WNV strain in C6/36 and C7-10 cells. Culex quinquefasciatus and Culex pipiens mosquitoes intrathoracically inoculated with NHUVandWNV, or solely withWNVas a control, were allowed to extrinsically incubate the viruses up to nine and 14 days, respectively, and transmissibility and replication of WNV was determined. The proportion of Cx. quinquefasciatus mosquitoes capable of transmitting WNV was significantly lower for the WNV/NHUV group than the WNV control at seven and nine days post inoculation (dpi, while no differences were observed in the Cx. pipiens inoculation group. By dpi nine, a 40% reduction in transmissibility in mosquitoes from the dual inoculation group was observed compared to the WNV-only control. These data indicate the potential that infection of some Culex spp. vectors with NHUV could serve as a barrier for efficient transmissibility of flaviviruses associated with human disease.

  14. Landscape epidemiology and machine learning: A geospatial approach to modeling West Nile virus risk in the United States

    Science.gov (United States)

    Young, Sean Gregory

    The complex interactions between human health and the physical landscape and environment have been recognized, if not fully understood, since the ancient Greeks. Landscape epidemiology, sometimes called spatial epidemiology, is a sub-discipline of medical geography that uses environmental conditions as explanatory variables in the study of disease or other health phenomena. This theory suggests that pathogenic organisms (whether germs or larger vector and host species) are subject to environmental conditions that can be observed on the landscape, and by identifying where such organisms are likely to exist, areas at greatest risk of the disease can be derived. Machine learning is a sub-discipline of artificial intelligence that can be used to create predictive models from large and complex datasets. West Nile virus (WNV) is a relatively new infectious disease in the United States, and has a fairly well-understood transmission cycle that is believed to be highly dependent on environmental conditions. This study takes a geospatial approach to the study of WNV risk, using both landscape epidemiology and machine learning techniques. A combination of remotely sensed and in situ variables are used to predict WNV incidence with a correlation coefficient as high as 0.86. A novel method of mitigating the small numbers problem is also tested and ultimately discarded. Finally a consistent spatial pattern of model errors is identified, indicating the chosen variables are capable of predicting WNV disease risk across most of the United States, but are inadequate in the northern Great Plains region of the US.

  15. Antibodies to West Nile virus in asymptomatic mammals, birds, and reptiles in the Yucatan Peninsula of Mexico.

    Science.gov (United States)

    Farfán-Ale, José A; Blitvich, Bradley J; Marlenee, Nicole L; Loroño-Pino, María A; Puerto-Manzano, Fernando; García-Rejón, Julián E; Rosado-Paredes, Elsy P; Flores-Flores, Luis F; Ortega-Salazar, Andres; Chávez-Medina, Jaidy; Cremieux-Grimaldi, Juan C; Correa-Morales, Favián; Hernández-Gaona, Gerson; Méndez-Galván, Jorge F; Beaty, Barry J

    2006-05-01

    Surveillance for evidence of West Nile virus (WNV) infection in taxonomically diverse vertebrates was conducted in the Yucatan Peninsula of Mexico in 2003 and 2004. Sera from 144 horses on Cozumel Island, Quintana Roo State, 415 vertebrates (257 birds, 52 mammals, and 106 reptiles) belonging to 61 species from the Merida Zoo, Yucatan State, and 7 farmed crocodiles in Ciudad del Carmen, Campeche State were assayed for antibodies to flaviviruses. Ninety (62%) horses on Cozumel Island had epitope-blocking enzyme-linked immunosorbent assay (ELISA) antibodies to flaviviruses, of which 75 (52%) were seropositive for WNV by plaque reduction neutralization test (PRNT). Blocking ELISA antibodies to flaviviruses also were detected in 13 (3%) animals in the Merida Zoo, including 7 birds and 2 mammals (a jaguar and coyote) seropositive for WNV by PRNT. Six (86%) crocodiles in Campeche State had PRNT-confirmed WNV infections. All animals were healthy at the time of serum collections and none had a history of WNV-like illness.

  16. West Nile virus infection rates in Culex nigripalpus (Diptera: Culicidae) do not reflect transmission rates in Florida.

    Science.gov (United States)

    Rutledge, C Roxanne; Day, Jonathan F; Lord, Cynthia C; Stark, Lillian M; Tabachnick, Walter J

    2003-05-01

    We describe the first documented field transmission of West Nile (WN) virus by a North American mosquito. WN was first detected in northern Florida in 2001. An intensive mosquito trapping and surveillance program was conducted in this region for four nights to assess mosquito transmission of WN. Four mosquito traps, each with a single sentinel chicken, were placed at five different locations on each of four nights. A total of 11,948 mosquitoes was collected, and 14 mosquito pools were found to contain WN, giving a minimum infection rate between 1.08 and 7.54 per 1,000. Only one of the 80 sentinel chickens seroconverted to WN, demonstrating a single mosquito transmission event during the study and a mosquito transmission rate of between 0.8 and 1 per 1,000. Culex nigripalpus Theobald was responsible for WN transmission to the sentinel chicken, although both Cx. nigripalpus and Culex quinquefasciatus Say were found infected with WN. Mosquito transmission rates are reported in this study for the first time for a WN outbreak. This information is essential to determine risk of human and animal infection.

  17. Economics of One Health: Costs and benefits of integrated West Nile virus surveillance in Emilia-Romagna.

    Directory of Open Access Journals (Sweden)

    Giulia Paternoster

    Full Text Available Since 2013 in Emilia-Romagna, Italy, surveillance information generated in the public health and in the animal health sectors has been shared and used to guide public health interventions to mitigate the risk of West Nile virus (WNV transmission via blood transfusion. The objective of the current study was to identify and estimate the costs and benefits associated with this One Health surveillance approach, and to compare it to an approach that does not integrate animal health information in blood donations safety policy (uni-sectoral scenario. Costs of human, animal, and entomological surveillance, sharing of information, and triggered interventions were estimated. Benefits were quantified as the averted costs of potential human cases of WNV neuroinvasive disease associated to infected blood transfusion. In the 2009-2015 period, the One Health approach was estimated to represent a cost saving of €160,921 compared to the uni-sectoral scenario. Blood donation screening was the main cost for both scenarios. The One Health approach further allowed savings of €1.21 million in terms of avoided tests on blood units. Benefits of the One Health approach due to short-term costs of hospitalization and compensation for transfusion-associated disease potentially avoided, were estimated to range from €0 to €2.98 million according to the probability of developing WNV neuroinvasive disease after receiving an infected blood transfusion.

  18. 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.

  19. Genetic variation associated with mammalian feeding in Culex pipiens from a West Nile virus epidemic region in Chicago, Illinois.

    Science.gov (United States)

    Huang, Shaoming; Hamer, Gabriel L; Molaei, Goudarz; Walker, Edward D; Goldberg, Tony L; Kitron, Uriel D; Andreadis, Theodore G

    2009-12-01

    Mosquitoes of the Culex pipiens complex are important vectors of West Nile virus in the United States. We examined the genetic variations of Cx. pipiens mosquitoes from Chicago, Illinois that were determined to be principally ornithophilic but exhibited a relatively higher inclination for mammalian hosts including humans. Microsatellite analysis of 10 polymorphic markers was performed on 346 engorged Cx. pipiens specimens with identified avian or mammalian blood meals. Our results indicated that there were no significant differences in allelic richness, the pattern of conformity to Hardy-Weinberg equilibrium, and linkage disequilibrium, nor was there overall genetic differentiation between specimens with avian- and mammalian-derived blood meals. However, Cx. pipiens form pipiens with mammalian- (including human-) derived blood meals had significantly higher ancestry (p 0.05) and the proportion of hybrids (p > 0.05) from Cx. quinquefasciatus (population from Harris Country, Texas). No temporal genetic variation was detected in accordance with the observation that there was no shift in blood feeding from birds to mammals. The results of this study in conjunction with regional host-feeding behavior suggest that the probability of genetic ancestry from Cx. pipiens f. molestus may predispose mosquitoes to feed more readily on mammals; however, the genetic mechanisms are unknown.

  20. Impact of extrinsic incubation temperature and virus exposure on vector competence of Culex pipiens quinquefasciatus Say (Diptera: Culicidae) for West Nile virus.

    Science.gov (United States)

    Richards, Stephanie L; Mores, Christopher N; Lord, Cynthia C; Tabachnick, Walter J

    2007-01-01

    Culex pipiens quinquefasciatus Say mosquitoes from a laboratory colony were exposed to artificial blood meals containing West Nile virus (WNV) and held at incubation temperatures approximating average daily temperatures that occur during Florida arboviral periods. Mosquitoes fed blood meals containing 6.2 logs plaque-forming units (pfu) WNV/mL and held at 25 degrees C, 28 degrees C, or 30 degrees C for 13 days exhibited significantly different rates of infection (30%, 52%, 93%) and dissemination (33%, 22%, 81%) across temperatures. In a separate experiment, Cx. p. quinquefasciatus mosquitoes were provided artificial blood meals with graded doses of WNV from 3.7 to 5.8 logs pfu/mL and maintained at 28 degrees C for 13 days. Rates of infection increased as a function of virus dose, but neither body titers nor dissemination rates were significantly different for mosquitoes that were infected by ingesting different amounts of WNV. Our findings indicate that efficiency of WNV infection and dissemination, and thereby transmission, in Cx. p. quinquefasciatus populations similar to our tested colony may also be diminished when fed blood meals containing less than 5.8 logs pfu WNV/mL and when environmental temperature falls below 30 degrees C. The relationship between the infection rate and dissemination rate changed at different temperatures. This relationship is likely complex and dependent on diverse interactions between factors such as incubation temperature and viremia, which should also be assessed for field populations.

  1. Epitope-blocking enzyme-linked immunosorbent assay to differentiate west nile virus from Japanese encephalitis virus infections in equine sera.

    Science.gov (United States)

    Kitai, Yoko; Shoda, Mizue; Kondo, Takashi; Konishi, Eiji

    2007-08-01

    West Nile virus (WNV) is now widely distributed worldwide, except in most areas of Asia where Japanese encephalitis virus (JEV) is distributed. Considering the movement and migration of reservoir birds, there is concern that WNV may be introduced in Asian countries. Although manuals and guidelines for serological tests have been created in Japan in preparedness for the introduction of WNV, differential diagnosis between WNV and JEV may be complicated by antigenic cross-reactivities between these flaviviruses. Here, we generated a monoclonal antibody specific for the nonstructural protein 1 (NS1) of WNV and established an epitope-blocking enzyme-linked immunosorbent assay that can differentiate WNV from JEV infections in horse sera. Under conditions well suited for our assay system, samples collected from 95 horses in Japan (regarded as negative for WNV antibodies), including those collected from horses naturally infected with JEV, showed a mean inhibition value of 8.2% and a standard deviation (SD) of 6.5%. However, inhibition values obtained with serum used as a positive control (obtained after 28 days from a horse experimentally infected with WNV) in nine separate experiments showed a mean of 54.4% and an SD of 7.1%. We tentatively determined 27.6% (mean + 3 x SD obtained with 95 negative samples) as the cutoff value to differentiate positive from negative samples. Under this criterion, two horses experimentally infected with WNV were diagnosed as positive at 12 and 14 days, respectively, after infection.

  2. Using avian surveillance in Ecuador to assess the imminence of West Nile virus incursion to Galápagos.

    Science.gov (United States)

    Eastwood, Gillian; Goodman, Simon J; Hilgert, Nancy; Cruz, Marilyn; Kramer, Laura D; Cunningham, Andrew A

    2014-01-01

    Infectious disease emergence represents a global threat to human, agricultural animal and wildlife health. West Nile virus (WNV) first emerged in the Americas in 1999 following its introduction to New York from the Old World. This flavivirus rapidly spread across much of North America, causing human, equine and avian mortalities and population declines of multiple wild bird species. It has now spread to Central and South America, and there is concern that the virus will reach the Galápagos Islands, a UNESCO World Heritage Site famous for its unique biodiversity, with potentially catastrophic results. Here, we use wild bird surveillance to examine the current WNV status in the Galapagos Islands and around the Ecuadorian city of Guayaquil (the main air and sea port serving Galápagos). We conducted serosurveys of wild birds on three Galápagos Islands (Baltra, San Cristobal and Santa Cruz) with direct transport links to the South American continent. In addition, dead birds killed by car collisions on Santa Cruz were tested for WNV infection. On mainland Ecuador, serosurveys of wild birds were conducted at three sites around Guayaquil. No evidence of WNV seropositivity or infection was detected. Although wider testing is recommended on the mainland, the study highlights a limit of WNV spread within South America. Our results indicate the continued absence of WNV on Galápagos and suggest the current likelihood of human-mediated transport of WNV to Galápagos to be low. The risk of emergence will almost certainly increase over time, however, and stringent biosecurity and surveillance measures should be put in place to minimise the risk of the introduction of WNV (and other alien pathogens) to Galápagos.

  3. Protection of horses from West Nile virus Lineage 2 challenge following immunization with a whole, inactivated WNV lineage 1 vaccine.

    Science.gov (United States)

    Bowen, Richard A; Bosco-Lauth, Angela; Syvrud, Kevin; Thomas, Anne; Meinert, Todd R; Ludlow, Deborah R; Cook, Corey; Salt, Jeremy; Ons, Ellen

    2014-09-22

    Over the last years West Nile virus (WNV) lineage 2 has spread from the African to the European continent. This study was conducted to demonstrate efficacy of an inactivated, lineage 1-based, WNV vaccine (Equip WNV) against intrathecal challenge of horses with a recent isolate of lineage 2 WNV. Twenty horses, sero-negative for WNV, were enrolled and were randomly allocated to one of two treatment groups: an unvaccinated control group (T01, n=10) and a group administered with Equip WNV (T02, n=10). Horses were vaccinated at Day 0 and 21 and were challenged at day 42 with WNV lineage 2, Nea Santa/Greece/2010. Personnel performing clinical observations were blinded to treatment allocation. Sixty percent of the controls had to be euthanized after challenge compared to none of the vaccinates. A significantly lower percentage of the vaccinated animals showed clinical disease (two different clinical observations present on the same day) on six different days of study and the percentage of days with clinical disease was significantly lower in the vaccinated group. A total of 80% of the non-vaccinated horses showed viremia while only one vaccinated animal was positive by virus isolation on a single occasion. Vaccinated animals started to develop antibodies against WNV lineage 2 from day 14 (2 weeks after the first vaccination) and at day 42 (the time of onset of immunity) they had all developed a strong antibody response. Histopathology scores for all unvaccinated animals ranged from mild to very severe in each of the tissues examined (cervical spinal cord, medulla and pons), whereas in vaccinated horses 8 of 10 animals had no lesions and 2 had minimal lesions in one tissue. In conclusion, Equip WNV significantly reduced the number of viremic horses, the duration and severity of clinical signs of disease and mortality following challenge with lineage 2 WNV. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Increased Pathogenicity of West Nile Virus (WNV by Glycosylation of Envelope Protein and Seroprevalence of WNV in Wild Birds in Far Eastern Russia

    Directory of Open Access Journals (Sweden)

    Hiroaki Kariwa

    2013-12-01

    Full Text Available In this review, we discuss the possibility that the glycosylation of West Nile (WN virus E-protein may be associated with enhanced pathogenicity and higher replication of WN virus. The results indicate that E-protein glycosylation allows the virus to multiply in a heat-stable manner and therefore, has a critical role in enhanced viremic levels and virulence of WN virus in young-chick infection model. The effect of the glycosylation of the E protein on the pathogenicity of WN virus in young chicks was further investigated. The results indicate that glycosylation of the WN virus E protein is important for viral multiplication in peripheral organs and that it is associated with the strong pathogenicity of WN virus in birds. The micro-focus reduction neutralization test (FRNT in which a large number of serum samples can be handled at once with a small volume (15 μL of serum was useful for differential diagnosis between Japanese encephalitis and WN virus infections in infected chicks. Serological investigation was performed among wild birds in the Far Eastern region of Russia using the FRNT. Antibodies specific to WN virus were detected in 21 samples of resident and migratory birds out of 145 wild bird samples in the region.

  5. An Update on the Potential of North American Mosquitoes (Diptera: Culicidae) to Transmit West Nile Virus

    National Research Council Canada - National Science Library

    Turell, Michael J; Dohm, David J; Sardelis, Michael R; O 'Guinn, Monica L; Andreadis, Theodore G; Blow, Jamie A

    2004-01-01

    .... To develop appropriate surveillance and control strategies, the identification of which mosquito species are competent vectors and how various factors influence their ability to transmit this virus must be determined...

  6. Zika virus detected in amniotic fluid and umbilical cord blood in an in vitro fertilization-conceived pregnancy in Venezuela.

    Science.gov (United States)

    Benjamin, Isaac; Fernández, Gissel; Figueira, José Valentin; Parpacén, Leticia; Urbina, María Teresa; Medina, Randolfo

    2017-06-01

    To describe the consequences of Zika virus infection at 10 weeks of gestation in an IVF-conceived pregnancy in Venezuela. A case report. Private assisted reproduction unit. A 36-year-old patient who conceived her first pregnancy through IVF and became infected with Zika virus at 10 weeks' gestation in Venezuela. In vitro fertilization with fresh ET. Clinical, laboratory, and imaging Zika diagnostic methods. Zika virus detection by real-time polymerase chain reaction (PCR) in maternal plasma, PCR in amniotic fluid and umbilical cord blood. Ultrasonography findings of anatomic abnormalities. Zika infection was confirmed at 10 weeks' gestation by real-time PCR; ultrasound results appeared normal. At 19 weeks' gestation, an ultrasound revealed biometry on three SDs below the means for all parameters but with no apparent anatomic abnormality. Zika virus was positive in maternal urine and amniotic fluid by PCR at 19 weeks' gestation. Ultrasound at 21 weeks + 4 days of gestation showed fetal cerebellar hypoplasia with ventricular dysmorphia, particularly marked on the left, consistent with microcephaly and ventriculomegaly. Because of the poor prognosis, pregnancy was interrupted at 24 weeks' gestation, in France. The PCR in umbilical cord blood taken in this procedure was positive for Zika virus. Initial ultrasound findings in pregnancy may not be informative. Only at 21 weeks + 4 days of gestation did an ultrasound reveal fetal microcephaly and ventriculomegaly. Combined clinical, laboratory, and imaging findings provided a complete picture of the severe damage caused by Zika infection. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Effect of West Nile virus DNA-plasmid vaccination on response to live virus challenge in red-tailed hawks (Buteo jamaicensis).

    Science.gov (United States)

    Redig, Patrick T; Tully, Thomas N; Ritchie, Branson W; Roy, Alma F; Baudena, M Alexandra; Chang, Gwong-Jen J

    2011-08-01

    To evaluate the safety and efficacy of an experimental adjuvanted DNA-plasmid vaccine against West Nile virus (WNV) in red-tailed hawks (Buteo jamaicensis). 19 permanently disabled but otherwise healthy red-tailed hawks of mixed ages and both sexes without detectable serum antibodies against WNV. Hawks were injected IM with an experimental WNV DNA-plasmid vaccine in an aluminum-phosphate adjuvant (n = 14) or with the adjuvant only (control group; 5). All birds received 2 injections at a 3-week interval. Blood samples for serologic evaluation were collected before the first injection and 4 weeks after the second injection (day 0). At day 0, hawks were injected SC with live WNV. Pre- and postchallenge blood samples were collected at intervals for 14 days for assessment of viremia and antibody determination; oropharyngeal and cloacal swabs were collected for assessment of viral shedding. Vaccination was not associated with morbidity or deaths. Three of the vaccinated birds seroconverted after the second vaccine injection; all other birds seroconverted following the live virus injection. Vaccinated birds had significantly less severe viremia and shorter and less-intense shedding periods, compared with the control birds. Use of the WNV DNA-plasmid vaccine in red-tailed hawks was safe, and vaccination attenuated but did not eliminate both the viremia and the intensity of postchallenge shedding following live virus exposure. Further research is warranted to conclusively determine the efficacy of this vaccine preparation for protection of red-tailed hawks and other avian species against WNV-induced disease.

  8. West Nile virus activity in Latin America and the Caribbean La actividad del virus del Nilo occidental en América Latina y el Caribe

    Directory of Open Access Journals (Sweden)

    Nicholas Komar

    2006-02-01

    Full Text Available OBJECTIVES: West Nile virus (Flavivirus: Flaviviridae; WNV has spread rapidly throughout the Caribbean Basin since its initial detection there in 2001. This report summarizes our current knowledge of WNV transmission in tropical America. METHODS: We reviewed the published literature and consulted with key public health officials to obtain unpublished data. RESULTS: West Nile virus infections first appeared in human residents of the Cayman Islands and the Florida Keys in 2001, and in apparently healthy Jamaican birds sampled early in 2002. Serologic evidence of WNV infection in 2002 was detected in horses, chickens and resident free-ranging birds in Guadeloupe, the Dominican Republic, and eastern Mexico. In 2003, WNV spread in Mexico and northern Central America, and serologic evidence was detected in the Bahamas, Puerto Rico and Cuba. In 2004, the first serologic evidence of WNV activity in South American ecosystems surfaced in September-October in Colombia and Trinidad, where domestic animals circulated WNV-neutralizing antibodies. CONCLUSIONS: The sparse reports of equine, human and avian disease in Latin America and the Caribbean is puzzling. Isolates are needed to evaluate viral attenuation or other possible explanations for reduced disease burden in tropical ecosystems.OBJETIVOS: El virus del Nilo occidental (VNO, familia Flaviviridae, género Flavivirus se ha propagado rápidamente por toda la cuenca del Caribe desde que se detectó por primera vez en 2001. En este informe se resumen nuestros conocimientos actuales acerca de la transmisión del VNO en zonas tropicales del continente americano. MÉTODOS: Revisamos todo lo que se ha publicado sobre el tema y consultamos a autoridades de salud clave para obtener datos inéditos. RESULTADOS: Las infecciones por el virus del Nilo occidental aparecieron por primera vez en seres humanos residentes de las Islas Caimán y de los Cayos de la Florida en 2001, y en pájaros de aspecto sano de los

  9. Induction of antigen-specific immune responses in mice by recombinant baculovirus expressing premembrane and envelope proteins of West Nile virus

    Directory of Open Access Journals (Sweden)

    Zhu Bibo

    2012-07-01

    Full Text Available Abstract Background West Nile Virus (WNV is an emerging arthropod-born flavivirus with increasing distribution worldwide that is responsible for a large proportion of viral encephalitis in humans and horses. Given that there are no effective antiviral drugs available for treatment of the disease, efforts have been directed to develop vaccines to prevent WNV infection. Recently baculovirus has emerged as a novel and attractive gene delivery vehicle for mammalian cells. Results In the present study, recombinant baculoviruses expressing WNV premembrane (prM and envelope (E proteins under the cytomegalovirus (CMV promoter with or without vesicular stomatitis virus glycoprotein (VSV/G were constructed. The recombinant baculoviruses designated Bac-G-prM/E and Bac-prM/E, efficiently express E protein in mammalian cells. Intramuscular injection of the two recombinant baculoviruses (at doses of 108 or 109 PFU/mouse induced the production of WNV-specific antibodies, neutralizing antibodies as well as gamma interferon (IFN-γ in a dose-dependent pattern. Interestingly, the recombinant baculovirus Bac-G-prM/E was found to be a more efficient immunogen than Bac-prM/E to elicit a robust immune response upon intramuscular injection. In addition, inoculation of baculovirus resulted in the secretion of inflammatory cytokines, such as TNF-α, IL-2 and IL-6. Conclusions These recombinant baculoviruses are capable of eliciting robust humoral and cellular immune responses in mice, and may be considered as novel vaccine candidates for West Nile Virus.

  10. The roles of mosquito and bird communities on the prevalence of West Nile virus in urban wetland and residential habitats

    Science.gov (United States)

    Johnson, Brian J.; Munafo, Kristin; Shappell, Laura; Tsipoura, Nellie; Robson, Mark; Ehrenfeld, Joan; Sukhdeo, Michael V. K.

    2014-01-01

    This study investigated the impacts of urban wetlands and their adjacent residential environments on the transmission dynamics of West Nile virus (WNV) within the state of New Jersey (USA). A working hypothesis was that urban wetlands decrease the local prevalence of WNV through the dilution effect from increased bird diversity, and through relative reductions in the numbers of competent avian host and mosquito species commonly associated with WNV. Surveys of mosquito and bird communities were undertaken at six urban wetlands and their adjacent residential environments over two seasons (2009, 2010). The community compositions of both avian and mosquito species differed significantly across habitats, and over relatively short geographical distances. Residential areas contained significantly higher proportions of WNV-competent mosquito species (31.25±5.3 %; e.g. Culex pipiens and Culex restuans), and WNV-competent avian host species (62.8±2.3 %, e.g. House Sparrow and American Robin) when compared to adjacent urban wetlands (13.5±2.1 %; 35.4±2.1 % respectively). Correspondingly, WNV infection rates within local Culex spp. populations indicate that WNV was more prevalent within residential areas (28.53/1000) compared to wetlands (16.77/1000). Large urban wetlands (>100 ha) produced significantly lower weekly WNV infection rates in local Culex spp. (6.67±2.84/1000) compared to small (urban wetlands contained significantly more species than small wetland patches. These results confirm that the community compositions of mosquito and avian hosts are important drivers in WNV infections, and that the ecological conditions that favor transmission are more strongly associated with urban residential environments than with adjacent urban wetlands. PMID:25484570

  11. Relationships between infection, dissemination, and transmission of West Nile virus RNA in Culex pipiens quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Richards, Stephanie L; Anderson, Sheri L; Lord, Cynthia C; Smartt, Chelsea T; Tabachnick, Walter J

    2012-01-01

    Culex pipiens quinquefasciatus Say fed blood containing 6.8 +/- 0.3 logs (mean +/- SE) plaque-forming units of West Nile virus (WNV)/ml were maintained at 28 degrees C for incubation periods (IP) of 7, 14, or 21 d. Several attributes of vector competence were determined at each IP using quantitative real-time reverse transcriptase polymerase chain reaction to estimate plaque forming unit equivalents including: infection rate (WNV-positive abdomens), dissemination rate (WNV-positive legs or thoraces), combined dissemination rate (WNV-positive legs and thoraces), transmission rate (WNV-positive saliva), and WNV titers in abdomens, legs, thoraces, and saliva. Each rate increased or was equivalent with increasing IP. Mosquitoes transmitting WNV in saliva also had significantly higher IP-dependent WNV titers in abdomens, legs, and thoraces. Titers of WNV in abdomens were significantly correlated with titers in legs and thoraces, but the degree of association changed with IP. However, titers of abdomens, legs, and thoraces were not correlated with WNV presence or titer in the saliva. The results show that WNV presence or titer in the saliva of infected Cx. p. quinquefasciatus was not directly influenced by processes involved in WNV replication in other tissues. The processes controlling midgut infection and escape are, in part, independent from the infection processes in other tissues. The relationship between infection, dissemination, and transmission varied over time. The infection and replication of WNV in different tissues is likely influenced by different barriers encountered during the extrinsic incubation period. The significance of these observations for understanding vector competence is discussed.

  12. The Degree of One Health Implementation in the West Nile Virus Integrated Surveillance in Northern Italy, 2016

    Directory of Open Access Journals (Sweden)

    Giulia Paternoster

    2017-09-01

    Full Text Available West Nile virus (WNV is endemic in the Po valley area, Northern Italy, and within the legal framework of the national plan for the surveillance of human vector-borne diseases, WNV surveillance has over time been implemented. The surveillance plans are based on the transdisciplinary and trans-sectorial collaboration between regional institutions involved in public, animal, and environmental health. This integrated surveillance targets mosquitoes, wild birds, humans, and horses and aims at early detecting the viral circulation and reducing the risk of infection in the human populations. The objective of our study was to assess the degree of One Health (OH implementation (OH-ness of the WNV surveillance system in three North Italian regions (Emilia-Romagna, Lombardy, Piedmont in 2016, following the evaluation protocol developed by the Network for Evaluation of One Health (NEOH. In detail, we (i described the OH initiative (drivers, outcomes and its system (boundaries, aim, dimensions, actors, stakeholders and (ii scored different aspects of this initiative (i.e., OH-thinking, -planning, -sharing, -learning, transdisciplinarity and leadership, with values from 0 (=no OH approach to 1 (=perfect OH approach. We obtained a mean score for each aspect evaluated. We reached high scores for OH thinking (0.90 and OH planning (0.89. Lower scores were attributed to OH sharing (0.83, transdisciplinarity and leadership (0.77, and OH learning (0.67, highlighting some critical issues related to communication and learning gaps. The strengths and weaknesses detected by the described quantitative evaluation will be investigated in detail by a qualitative evaluation (process evaluation, aiming to provide a basis for the development of shared recommendations to refine the initiative and conduct it in a more OH-oriented perspective.

  13. Cost-Effectiveness of Alternative Blood-Screening Strategies for West Nile Virus in the United States.

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available BACKGROUND: West Nile virus (WNV is endemic in the US, varying seasonally and by geographic region. WNV can be transmitted by blood transfusion, and mandatory screening of blood for WNV was recently introduced throughout the US. Guidelines for selecting cost-effective strategies for screening blood for WNV do not exist. METHODS AND FINDINGS: We conducted a cost-effectiveness analysis for screening blood for WNV using a computer-based mathematical model, and using data from prospective studies, retrospective studies, and published literature. For three geographic areas with varying WNV-transmission intensity and length of transmission season, the model was used to estimate lifetime costs, quality-adjusted life expectancy, and incremental cost-effectiveness ratios associated with alternative screening strategies in a target population of blood-transfusion recipients. We compared the status quo (baseline screening using a donor questionnaire to several strategies which differed by nucleic acid testing of either pooled or individual samples, universal versus targeted screening of donations designated for immunocompromised patients, and seasonal versus year-long screening. In low-transmission areas with short WNV seasons, screening by questionnaire alone was the most cost-effective strategy. In areas with high levels of WNV transmission, seasonal screening of individual samples and restricting screening to blood donations designated for immunocompromised recipients was the most cost-effective strategy. Seasonal screening of the entire recipient pool added minimal clinical benefit, with incremental cost-effectiveness ratios exceeding US$1.7 million per quality-adjusted life-year gained. Year-round screening offered no additional benefit compared to seasonal screening in any of the transmission settings. CONCLUSIONS: In areas with high levels of WNV transmission, seasonal screening of individual samples and restricting screening to blood donations

  14. 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.

  15. Phrenic nerve deficits and neurological immunopathology associated with acute West Nile virus infection in mice and hamsters.

    Science.gov (United States)

    Zukor, Katherine; Wang, Hong; Hurst, Brett L; Siddharthan, Venkatraman; Van Wettere, Arnaud; Pilowsky, Paul M; Morrey, John D

    2017-04-01

    Neurological respiratory deficits are serious outcomes of West Nile virus (WNV) disease. WNV patients requiring intubation have a poor prognosis. We previously reported that WNV-infected rodents also appear to have respiratory deficits when assessed by whole-body plethysmography and diaphragmatic electromyography. The purpose of this study was to determine if the nature of the respiratory deficits in WNV-infected rodents is neurological and if deficits are due to a disorder of brainstem respiratory centers, cervical spinal cord (CSC) phrenic motor neuron (PMN) circuitry, or both. We recorded phrenic nerve (PN) activity and found that in WNV-infected mice, PN amplitude is reduced, corroborating a neurological basis for respiratory deficits. These results were associated with a reduction in CSC motor neuron number. We found no dramatic deficits, however, in brainstem-mediated breathing rhythm generation or responses to hypercapnia. PN frequency and pattern parameters were normal, and all PN parameters changed appropriately upon a CO 2 challenge. Histological analysis revealed generalized microglia activation, astrocyte reactivity, T cell and neutrophil infiltration, and mild histopathologic lesions in both the brainstem and CSC, but none of these were tightly correlated with PN function. Similar results in PN activity, brainstem function, motor neuron number, and histopathology were seen in WNV-infected hamsters, except that histopathologic lesions were more severe. Taken together, the results suggest that respiratory deficits in acute WNV infection are primarily due to a lower motor neuron disorder affecting PMNs and the PN rather than a brainstem disorder. Future efforts should focus on markers of neuronal dysfunction, axonal degeneration, and myelination.

  16. Cost-effectiveness of alternative blood-screening strategies for West Nile Virus in the United States.

    Directory of Open Access Journals (Sweden)

    Caroline T Korves

    2006-02-01

    Full Text Available West Nile virus (WNV is endemic in the US, varying seasonally and by geographic region. WNV can be transmitted by blood transfusion, and mandatory screening of blood for WNV was recently introduced throughout the US. Guidelines for selecting cost-effective strategies for screening blood for WNV do not exist.We conducted a cost-effectiveness analysis for screening blood for WNV using a computer-based mathematical model, and using data from prospective studies, retrospective studies, and published literature. For three geographic areas with varying WNV-transmission intensity and length of transmission season, the model was used to estimate lifetime costs, quality-adjusted life expectancy, and incremental cost-effectiveness ratios associated with alternative screening strategies in a target population of blood-transfusion recipients. We compared the status quo (baseline screening using a donor questionnaire to several strategies which differed by nucleic acid testing of either pooled or individual samples, universal versus targeted screening of donations designated for immunocompromised patients, and seasonal versus year-long screening. In low-transmission areas with short WNV seasons, screening by questionnaire alone was the most cost-effective strategy. In areas with high levels of WNV transmission, seasonal screening of individual samples and restricting screening to blood donations designated for immunocompromised recipients was the most cost-effective strategy. Seasonal screening of the entire recipient pool added minimal clinical benefit, with incremental cost-effectiveness ratios exceeding USD 1.7 million per quality-adjusted life-year gained. Year-round screening offered no additional benefit compared to seasonal screening in any of the transmission settings.In areas with high levels of WNV transmission, seasonal screening of individual samples and restricting screening to blood donations designated for immunocompromised recipients is cost

  17. Noncoding Subgenomic Flavivirus RNA Is Processed by the Mosquito RNA Interference Machinery and Determines West Nile Virus Transmission by Culex pipiens Mosquitoes.

    Science.gov (United States)

    Göertz, G P; Fros, J J; Miesen, P; Vogels, C B F; van der Bent, M L; Geertsema, C; Koenraadt, C J M; van Rij, R P; van Oers, M M; Pijlman, G P

    2016-11-15

    Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5'-3' exoribonuclease XRN1/Pacman on conserved RNA structures in the 3' untranslated region (UTR) of the viral genomic RNA. sfRNA production is conserved in insect-specific, mosquito-borne, and tick-borne flaviviruses and flaviviruses with no known vector, suggesting a pivotal role for sfRNA in the flavivirus life cycle. Here, we investigated the function of sfRNA during WNV infection of Culex pipiens mosquitoes and evaluated its role in determining vector competence. An sfRNA1-deficient WNV was generated that displayed growth kinetics similar to those of wild-type WNV in both RNA interference (RNAi)-competent and -compromised mosquito cell lines. Small-RNA deep sequencing of WNV-infected mosquitoes indicated an active small interfering RNA (siRNA)-based antiviral response for both the wild-type and sfRNA1-deficient viruses. Additionally, we provide the first evidence that sfRNA is an RNAi substrate in vivo Two reproducible small-RNA hot spots within the 3' UTR/sfRNA of the wild-type virus mapped to RNA stem-loops SL-III and 3' SL, which stick out of the three-dimensional (3D) sfRNA structure model. Importantly, we demonstrate that sfRNA-deficient WNV displays significantly decreased infection and transmission rates in vivo when administered via the blood meal. Finally, we show that transmission and infection rates are not affected by sfRNA after intrathoracic injection, thereby identifying sfRNA as a key driver to overcome the mosquito midgut infection barrier. This is the first report to describe a key biological function of sfRNA for flavivirus infection of the arthropod vector, providing an explanation for the strict conservation of sfRNA production. Understanding the flavivirus transmission

  18. 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.

  19. Epidemiology and spatio-temporal analysis of West Nile virus in horses in Spain between 2010 and 2016.

    Science.gov (United States)

    García-Bocanegra, I; Belkhiria, J; Napp, S; Cano-Terriza, D; Jiménez-Ruiz, S; Martínez-López, B

    2018-04-01

    During the last decade, West Nile virus (WNV) outbreaks have increased sharply in both horses and human in Europe. The aims of this study were to evaluate characteristics and spatio-temporal distribution of WNV outbreaks in horses in Spain between 2010 and 2016 in order to identify the environmental variables most associated with WNV occurrence and to generate high-resolution WNV suitability maps to inform risk-based surveillance strategies in this country. Between August 2010 and November 2016, a total of 403 WNV suspected cases were investigated, of which, 177 (43.9%) were laboratory confirmed. Mean values of morbidity, mortality and case fatality rates were 7.5%, 1.6% and 21.2%, respectively. The most common clinical symptoms were as follows: tiredness/apathy, recumbency, muscular tremor, ataxia, incoordination and hyperaesthesia. The outbreaks confirmed during the last 7 years, with detection of WNV RNA lineage 1 in 2010, 2012, 2013, 2015 and 2016, suggest an endemic circulation of the virus in Spain. The spatio-temporal distribution of WNV outbreaks in Spain was not homogeneous, as most of them (92.7%) were concentrated in western part of Andalusia (southern Spain) and significant clusters were detected in this region in two non-consecutive years. These findings were supported by the results of the space-time scan statistics permutation model. A presence-only MaxEnt ecological niche model was used to generate a suitability map for WNV occurrence in Andalusia. The most important predictors selected by the Ecological Niche Modeling were as follows: mean annual temperature (49.5% contribution), presence of Culex pipiens (19.5% contribution), mean annual precipitation (16.1% contribution) and distance to Ramsar wetlands (14.9% contribution). Our results constitute an important step for understanding WNV emergence and spread in Spain and will provide valuable information for the development of more cost-effective surveillance and control programmes and improve the

  20. Petroleum. [Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    An introductory chapter of world wide petroleum history is followed by a comprehensive record of the petroliferous basins of Venezuela. Exploration, productivity, production statistics, reserves, geologic structures, and the distribution of oil and gas fields are described separately for the Maracaibo-Falcon basin, Apure-Barinas basin, E. Venezuela basin, and Tuy-Cariaco basin. The descriptions include geographic distribution, geomorphologic outline of the basins, lithology and thickness of sediments, structural development, present structural conditions in which oil and gas fields occur, and their distribution in the basins. Economic factors are discussed in an appendix. 145 references.

  1. 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.

  2. Ebola Virus Epidemic in West Africa and Beyond

    Directory of Open Access Journals (Sweden)

    Oscar G Gómez-Duarte

    2014-10-01

    Full Text Available Is there a reason to fear that an Ebola outbreak may strike Latin America? The fear may not be unreasonable taking into account the history of epidemics that have affected the American continent since colonization times in 1492. Old World small pox epidemics spread and killed millions of Native Americans north and south from the equator. Imported West Nile virus infections reported in New York in 1999 dramatically spread East to West of the United States. Most recently, Chikungunya virus arrived to Central America in 2013 and has already infected close to 1 million people in Mexico, Central American countries, Brazil, Colombia, Ecuador, Guyanas, Paraguay, and Venezuela.

  3. 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.

  4. Spatial Analysis of West Nile Virus: Predictive Risk Modeling of a Vector-borne Infectious Disease in Illinois by Means of NASA Earth Observation Systems

    Science.gov (United States)

    Renneboog, Nathan; Gathings, David; Hemmings, Sarah; Makasa, Emmanuel; Omer, Wigdan; Tipre, Meghan; Wright, Catherine; McAllister, Marilyn; Luvall, Jeffrey C.

    2009-01-01

    West Nile Virus is a mosquito-borne virus of the family Flaviviridae. It infects birds and various mammals, including humans, and can cause encephalitis that may prove fatal, notably among vulnerable populations. Since its identification in New York City in 1999, WNV has become established in a broad range of ecological settings throughout North America, infecting more than 25,300 people and killing 1133 as of 2008 (CDC,2009). WNV is transmitted by mosquitoes that feed on infected birds. As a result, the degree of human infection depends on local ecology and human exposure. This study hypothesizes that remote sensing and GIS can be used to analyze environmental determinants of WNV transmission, such as climate, elevation, land cover, and vegetation densities, to map areas of WNV risk for surveillance and intervention.

  5. 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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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…

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

    Science.gov (United States)

    Diaz-Badillo, Alvaro; Bolling, Bethany G; Perez-Ramirez, Gerardo; Moore, Chester G; Martinez-Munoz, Jorge P; Padilla-Viveros, America A; Camacho-Nuez, Minerva; Diaz-Perez, Alfonso; Beaty, Barry J; Munoz, Maria de Lourdes

    2011-05-09

    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. 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. 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. quinquefasciatus were also collected and identified. The

  8. Economic appraisal of the public control and prevention strategy against the 2010 West Nile Virus outbreak in Central Macedonia, Greece.

    Science.gov (United States)

    Kolimenakis, A; Bithas, K; Richardson, C; Latinopoulos, D; Baka, A; Vakali, A; Hadjichristodoulou, C; Mourelatos, S; Kalaitzopoulou, S; Gewehr, S; Michaelakis, A; Koliopoulos, G

    2016-02-01

    The aim of the present paper is to evaluate the economic efficiency of the public control and prevention strategies to tackle the 2010 West Nile Virus (WNV) outbreak in the Region of Central Macedonia, Greece. Efficiency is examined on the basis of the public prevention costs incurred and their potential in justifying the costs arising from health and nuisance impacts in the succeeding years. Economic appraisal of public health management interventions. Prevention and control cost categories including control programmes, contingency planning and blood safety testing, are analyzed based on market prices. A separate cost of illness approach is conducted for the estimation of medical costs and productivity losses from 2010 to 2013 and for the calculation of averted health impacts. The averted mosquito nuisance costs to households are estimated on the basis of a contingent valuation study. Based on these findings, a limited cost-benefit analysis is employed in order to evaluate the economic efficiency of these strategies in 2010-2013. Results indicate that cost of illness and prevention costs fell significantly in the years following the 2010 outbreak, also as a result of the epidemic coming under control. According to the contingent valuation survey, the annual average willingness to pay to eliminate the mosquito problem in the study area ranged between 22 and 27 € per household. Cost-benefit analysis indicates that the aggregate benefit of implementing the previous 3-year strategy creates a net socio-economic benefit in 2013. However the spread of the WNV epidemic and the overall socio-economic consequences, had the various costs not been employed, remain unpredictable and extremely difficult to calculate. The application of a post epidemic strategy appears to be of utmost importance for public health safety. An updated well designed survey is needed for a more precise definition of the optimum prevention policies and levels and for the establishment of the various

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

    Directory of Open Access Journals (Sweden)

    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

  10. Asymmetric effects of native and exotic invasive shrubs on ecology of the West Nile virus vector Culex pipiens (Diptera: Culicidae).

    Science.gov (United States)

    Gardner, Allison M; Allan, Brian F; Frisbie, Lauren A; Muturi, Ephantus J

    2015-06-16

    Exotic invasive plants alter the structure and function of native ecosystems and may influence the distribution and abundance of arthropod disease vectors by modifying habitat quality. This study investigated how invasive plants alter the ecology of Culex pipiens, an important vector of West Nile virus (WNV) in northeastern and midwestern regions of the United States. Field and laboratory experiments were conducted to test the hypothesis that three native leaf species (Rubus allegheniensis, blackberry; Sambucus canadensis, elderberry; and Amelanchier laevis, serviceberry), and three exotic invasive leaf species (Lonicera maackii, Amur honeysuckle; Elaeagnus umbellata, autumn olive; and Rosa multiflora, multiflora rose) alter Cx. pipiens oviposition site selection, emergence rates, development time, and adult body size. The relative abundance of seven bacterial phyla in infusions of the six leaf species also was determined using quantitative real-time polymerase chain reaction to test the hypothesis that variation in emergence, development, and oviposition site selection is correlated to differences in the diversity and abundance of bacteria associated with different leaf species, important determinants of nutrient quality and availability for mosquito larvae. Leaf detritus from invasive honeysuckle and autumn olive yielded significantly higher adult emergence rates compared to detritus from the remaining leaf species and honeysuckle alleviated the negative effects of intraspecific competition on adult emergence. Conversely, leaves of native blackberry acted as an ecological trap, generating high oviposition but low emergence rates. Variation in bacterial flora associated with different leaf species may explain this asymmetrical production of mosquitoes: emergence rates and oviposition rates were positively correlated to bacterial abundance and diversity, respectively. We conclude that the displacement of native understory plant species by certain invasive shrubs

  11. Entomologic and avian investigations of an epidemic of West Nile fever in Romania in 1996, with serologic and molecular characterization of a virus isolate from mosquitoes.

    Science.gov (United States)

    Savage, H M; Ceianu, C; Nicolescu, G; Karabatsos, N; Lanciotti, R; Vladimirescu, A; Laiv, L; Ungureanu, A; Romanca, C; Tsai, T F

    1999-10-01

    Between July and October 1996, a West Nile (WN) fever epidemic occurred in the southern plain and Danube Valley of Romania and in the capital city of Bucharest, resulting in hundreds of neurologic cases and 17 fatalities. In early October 1996, entomologic and avian investigations of the epidemic were conducted in the city of Bucharest and nearby rural areas. Thirty (41%) of 73 domestic fowl sampled had neutralizing antibody to WN virus, including 5 of 13 ducks (38%), 1 of 1 goose, 19 of 52 chickens (37%), 1 of 1 peahen, and 4 of 6 turkeys (67%). Seroprevalence in domestic fowl (27%, or 7 of 26) from the urban Bucharest site was not significantly different (P = 0.08, by Fisher's exact test) than rates at three rural sites (50%, or 23 of 46). Serum collected from one of 12 Passeriformes, an Erithacus rubecula, was positive for neutralizing antibody to WN virus. A total of 5,577 mosquitoes representing seven taxa were collected. Culex pipiens pipiens accounted for 96% of the mosquitoes collected. A single virus isolate, RO97-50, was obtained from a pool of 30 Cx. p. pipiens females aspirated from the walls and ceiling of a blockhouse located near the center of Bucharest, resulting in a minimum infection rate of 0.19 per 1,000. Antisera prepared against RO97-50 failed to distinguish among RO97-50, WN virus strain Eg101, and Kunjin (KUN) virus strain MRM16. A 2,323-basepair DNA fragment of the envelope (E) glycoprotein gene from RO97-50 and a Romanian WN virus strain obtained from a human cerebrospinal fluid sample, RO96-1030, were sequenced. Phylogenetic analyses of 23 WN virus strains and one KUN virus strain using the amino acid and nucleotide sequences for a small portion of the E gene suggest the existence of two large lineages of viruses. Bootstrap analysis of the nucleotide alignment indicated strong support (95%) for a lineage composed of WN virus strains from northern Africa, including isolates from Egypt and Algeria, and west, central, and east Africa, all of

  12. 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

  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. © 2016 The Authors. Medical and Veterinary Entomology published by John Wiley & Sons Ltd on behalf of Royal Entomological Society.

  14. [In silico evaluation of an aviar influenza AH5N1 virus outbreak with human to human transmission: effects of sanitary measures in Valencia, Venezuela, 2012].

    Science.gov (United States)

    Reggeti, Mariana; Romero, Emilse; Eblen-Zajjur, Antonio

    2016-06-01

    There is a risk for an avian influenza AH5N1 virus pandemia. To estimate the magnitude and impact of an AH5N1 pandemic in areas of Latin-America in order to design interventions and to reduce morbidity-mortality. The InfluSim program was used to simulate a highly pathogenic AH5N1 aviar virus epidemic outbreak with human to human transmission in Valencia, Venezuela. We estimated the day of maximal number of cases, number of moderately and severely ill patients, exposed individuals, deaths and associated costs for 5 different interventions: absence of any intervention; implementation of antiviral treatment; reduction of 20% in population general contacts; closure of 20% of educational institutions; and reduction of 50% in massive public gatherings. Simulation parameters used were: population: 829.856 persons, infection risk 6-47%, contagiousness Index Rh o 2,5; relative contagiousness 90%, overall lethality 64,1% and, costs according to the official basic budget. For an outbreak lasting 200 days direct and indirect deaths by intervention strategies would be: 29,907; 29,900; 9,701; 29,295 and 14,752. Costs would follow a similar trend. Reduction of 20% in general population contacts results in a significant reduction of up to 68% of cases. The outbreak would collapse the health care system. Antiviral treatment would not be efficient during the outbreak. Interpersonal contact reduction proved to be the best sanitary measure to control an AH5N1 theoretical epidemic outbreak.

  15. West Nile Virus

    Science.gov (United States)

    ... birds, and mosquitoes, processes underlying WNV emergence and ecological patterns in the United States, and insecticide resistance. ... Clinical Training Programs Allergy and Immunology Training Program Transition Program in Clinical Research Infectious Diseases Fellowship Program ...

  16. West Nile virus

    Science.gov (United States)

    ... in Uganda in eastern Africa. It was first discovered in the United States in the summer of ... Conditions that weaken the immune system, such as HIV/AIDS, organ transplants, and recent chemotherapy Older or ...

  17. West Nile Virus

    Science.gov (United States)

    ... improve a person's chances of recovery. Tips for Protecting Yourself Although it's unlikely you'll be infected ... face) and don't use repellent on your eyes or mouth. Wash repellent off with soap and ...

  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

    Directory of Open Access Journals (Sweden)

    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. 2014: A Record-Breaking Year for West Nile Virus Positive Mosquito Pools in Harris County and the City of Houston, Texas.

    Science.gov (United States)

    Randle, Yvonne H; Freeman, Cheryl Battle; Jackson, Monique; Reyna, Martin; Debboun, Mustapha

    2016-01-01

    In the 14 years since the emergence of West Nile virus (WNV) in Harris County and the city of Houston, Texas, the number of mosquitoes infected with the virus has fluctuated with several high and low count years. During this 14-year period, mosquito surveillance operational areas in Harris County were expanded from 248 to 268 and the distribution of the virus activity in mosquitoes varied from year to year. Operational areas with WNV infected mosquitoes increased from 137 in 2002 to 197 in 2006, decreased to 71 areas in 2007, and to an all-time low of 18 in 2008. The number increased to 78 areas in 2009, 96 in 2010, 133 in 2011, and 177 in 2012, but fell to 73 in 2013. However, 234 areas were confirmed in 2014, and only 138 in 2015. The WNV transmission was high in 2002 with 227 WNV positive mosquito pools. The number of positive mosquitoes remained elevated for a number of years and then declined from 2007 to 2010. Three record high years for WNV activity were: 2005, 2006, and 2011 with 698, 838, and 605 confirmed positive mosquito pools, respectively. Viral activity declined in 2012, followed by a marked decline in 2013 with only 147 WNV positive mosquito pools. In 2014, a record-breaking number of 1,286 WNV positive mosquito pools were confirmed in Harris County and the city of Houston, the most ever in a single season, while 406 were confirmed in 2015.

  1. 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.

  2. Detection of West Nile virus-specific antibodies and nucleic acid in horses and mosquitoes, respectively, in Nuevo Leon State, northern Mexico, 2006-2007.

    Science.gov (United States)

    Ibarra-Juarez, L; Eisen, L; Bolling, B G; Beaty, B J; Blitvich, B J; Sanchez-Casas, R M; Ayala-Sulca, Y O; Fernandez-Salas, I

    2012-09-01

    In the last 5 years, there has been only one reported human case of West Nile virus (WNV) disease in northern Mexico. To determine if the virus was still circulating in this region, equine and entomological surveillance for WNV was conducted in the state of Nuevo Leon in northern Mexico in 2006 and 2007. A total of 203 horses were serologically assayed for antibodies to WNV using an epitope-blocking enzyme-linked immunosorbent assay (bELISA). Seroprevalences for WNV in horses sampled in 2006 and 2007 were 26% and 45%, respectively. Mosquito collections in 2007 produced 7365 specimens representing 15 species. Culex mosquitoes were screened for WNV RNA and other genera (Mansonia, Anopheles, Aedes, Psorophora and Uranotaenia) were screened for flaviviruses using reverse-transcription (RT)-PCR. Two pools consisting of Culex spp. mosquitoes contained WNV RNA. Molecular species identification revealed that neither pool included Culex quinquefasciatus (Say) (Diptera:Culicidae) complex mosquitoes. No evidence of flaviviruses was found in the other mosquito genera examined. These data provide evidence that WNV is currently circulating in northern Mexico and that non-Cx. quinquefasciatus spp. mosquitoes may be participating in the WNV transmission cycle in this region. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

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

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    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.

  4. Integrating Environmental and Mosquito Data to Model Disease: Evaluating Alternative Modeling Approaches for Forecasting West Nile Virus in South Dakota, USA

    Science.gov (United States)

    Davis, J. K.; Vincent, G. P.; Hildreth, M.; Kightlinger, L.; Carlson, C.; Wimberly, M. C.

    2017-12-01

    South Dakota has the highest annual incidence of human cases of West Nile virus (WNV) in all US states, and human cases can vary wildly among years; predicting WNV risk in advance is a necessary exercise if public health officials are to respond efficiently and effectively to risk. Case counts are associated with environmental factors that affect mosquitoes, avian hosts, and the virus itself. They are also correlated with entomological risk indices obtained by trapping and testing mosquitoes. However, neither weather nor insect data alone provide a sufficient basis to make timely and accurate predictions, and combining them into models of human disease is not necessarily straightforward. Here we present lessons learned in three years of making real-time forecasts of this threat to public health. Various methods of integrating data from NASA's North American Land Data Assimilation System (NLDAS) with mosquito surveillance data were explored in a model comparison framework. We found that a model of human disease summarizing weather data (by polynomial distributed lags with seasonally-varying coefficients) and mosquito data (by a mixed-effects model that smooths out these sparse and highly-variable data) made accurate predictions of risk, and was generalizable enough to be recommended in similar applications. A model based on lagged effects of temperature and humidity provided the most accurate predictions. We also found that model accuracy was improved by allowing coefficients to vary smoothly throughout the season, giving different weights to different predictor variables during different parts of the season.

  5. 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.

  6. 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

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    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.

  7. Modification of the Host Cell Lipid Metabolism Induced by Hypolipidemic Drugs Targeting the Acetyl Coenzyme A Carboxylase Impairs West Nile Virus Replication.

    Science.gov (United States)

    Merino-Ramos, Teresa; Vázquez-Calvo, Ángela; Casas, Josefina; Sobrino, Francisco; Saiz, Juan-Carlos; Martín-Acebes, Miguel A

    2016-01-01

    West Nile virus (WNV) is a neurotropic flavivirus transmitted by the bite of mosquitoes that causes meningitis and encephalitis in humans, horses, and birds. Several studies have highlighted that flavivirus infection is highly dependent on cellular lipids for virus replication and infectious particle biogenesis. The first steps of lipid synthesis involve the carboxylation of acetyl coenzyme A (acetyl-CoA) to malonyl-CoA that is catalyzed by the acetyl-CoA carboxylase (ACC). This makes ACC a key enzyme of lipid synthesis that is currently being evaluated as a therapeutic target for different disorders, including cancers, obesity, diabetes, and viral infections. We have analyzed the effect of the ACC inhibitor 5-(tetradecyloxy)-2-furoic acid (TOFA) on infection by WNV. Lipidomic analysis of TOFA-treated cells confirmed that this drug reduced the cellular content of multiple lipids, including those directly implicated in the flavivirus life cycle (glycerophospholipids, sphingolipids, and cholesterol). Treatment with TOFA significantly inhibited the multiplication of WNV in a dose-dependent manner. Further analysis of the antiviral effect of this drug showed that the inhibitory effect was related to a reduction of viral replication. Furthermore, treatment with another ACC inhibitor, 3,3,14,14-tetramethylhexadecanedioic acid (MEDICA 16), also inhibited WNV infection. Interestingly, TOFA and MEDICA 16 also reduced the multiplication of Usutu virus (USUV), a WNV-related flavivirus. These results point to the ACC as a druggable cellular target suitable for antiviral development against WNV and other flaviviruses. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Minocycline Has Anti-inflammatory Effects and Reduces Cytotoxicity in an Ex Vivo Spinal Cord Slice Culture Model of West Nile Virus Infection.

    Science.gov (United States)

    Quick, Eamon D; Seitz, Scott; Clarke, Penny; Tyler, Kenneth L

    2017-11-15

    West Nile virus (WNV) is a neurotropic flavivirus that can cause significant neurological disease. Mouse models of WNV infection demonstrate that a proinflammatory environment is induced within the central nervous system (CNS) after WNV infection, leading to entry of activated peripheral immune cells. We utilized ex vivo spinal cord slice cultures (SCSC) to demonstrate that anti-inflammatory mechanisms may also play a role in WNV-induced pathology and/or recovery. Microglia are a type of macrophage that function as resident CNS immune cells. Similar to mouse models, infection of SCSC with WNV induces the upregulation of proinflammatory genes and proteins that are associated with microglial activation, including the microglial activation marker Iba1 and CC motif chemokines CCL2, CCL3, and CCL5. This suggests that microglia assume a proinflammatory phenotype in response to WNV infection similar to the proinflammatory (M1) activation that can be displayed by other macrophages. We now show that the WNV-induced expression of these and other proinflammatory genes was significantly decreased in the presence of minocycline, which has antineuroinflammatory properties, including the ability to inhibit proinflammatory microglial responses. Minocycline also caused a significant increase in the expression of anti-inflammatory genes associated with alternative anti-inflammatory (M2) macrophage activation, including interleukin 4 (IL-4), IL-13, and FIZZ1. Minocycline-dependent alterations to M1/M2 gene expression were associated with a significant increase in survival of neurons, microglia, and astrocytes in WNV-infected slices and markedly decreased levels of inducible nitric oxide synthase (iNOS). These results demonstrate that an anti-inflammatory environment induced by minocycline reduces viral cytotoxicity during WNV infection in ex vivo CNS tissue. IMPORTANCE West Nile virus (WNV) causes substantial morbidity and mortality, with no specific therapeutic treatments available

  9. Identificación morfológica de Ehrlichia sp. en las plaquetas de pacientes con infección por virus de la inmunodeficiencia humana, en Venezuela Morphologic identification of Ehrlichia sp. in the platelets of patients infected with the human immunodeficiency virus in Venezuela

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    Irene del Carmen de Tamí

    2004-11-01

    Full Text Available OBJETIVO: Determinar la frecuencia de infección por bacterias del género Ehrlichia en una población de pacientes con infección por virus de la inmunodeficiencia humana (VIH. Como se sabe, la infección por VIH suele culminar en el síndrome de inmunodeficiencia adquirida (SIDA después de un período variable en que la persona queda expuesta a distintos tipos de infecciones oportunistas, cuya gravedad varía según el deterioro de su sistema inmunitario. La ehrliquiosis humana es una enfermedad infecciosa de reconocimiento reciente que se transmite por garrapatas y que es causada por especies de Ehrlichia. Se trata de microorganismos gramnegativos, intracelulares obligados, que muestran tropismo por células sanguíneas (leucocitos y plaquetas. En Venezuela se identificó por primera vez en seres humanos en 1994, con la detección de microcolonias (mórulas en el citoplasma de plaquetas. MATERIAL Y MÉTODOS: Para el estudio se reunieron muestras de sangre periférica de 87 pacientes con seropositividad a VIH recibidos en el Laboratorio de Inmunología del Instituto de Oncología y Hematología, en Caracas, Venezuela, que es uno de los centros de referencia nacionales para casos de infección por VIH. Se revisaron retrospectivamente, al microscopio óptico, frotis elaborados con capa blanca sanguínea concentrada, teñidos con colorante de Wright y sellados con resina para su conservación. RESULTADO: Se identificó Ehrlichia trombocítica en 12 de los 87 sujetos del estudio, es decir, en 13,8%. CONCLUSIÓN: La identificación de Ehrlichia trombocítica en pacientes seropositivos sugiere la necesidad de tener en cuenta la ehrliquiosis como posible diagnóstico en la población con infección por VIH.OBJECTIVE: To determine the frequency of infection by bacteria of the genus Ehrlichia in a population of patients infected with the human immunodeficiency virus (HIV. As is widely recognized, HIV infection is usually followed by the acquired

  10. Diagnostic sensitivity and specificity of in situ hybridization and immunohistochemistry for Eastern equine encephalitis virus and West Nile virus in formalin-fixed, paraffin-embedded brain tissue of horses.

    Science.gov (United States)

    Pennick, Kate E; McKnight, Christy A; Patterson, Jon S; Latimer, Kenneth S; Maes, Roger K; Wise, Annabel G; Kiupel, Matti

    2012-03-01

    Immunohistochemistry (IHC) and in situ hybridization (ISH) can be used either to detect or to differentiate between Eastern equine encephalitis virus (EEEV) and West Nile virus (WNV) within formalin-fixed, paraffin-embedded (FFPE) brain tissue of horses. To compare the diagnostic sensitivity and specificity of ISH and IHC, FFPE brain tissue from 20 EEEV-positive horses and 16 WNV-positive horses were tested with both EEEV and WNV oligoprobes and EEEV- and WNV-specific antibodies. Reverse transcription polymerase chain reaction (RT-PCR) for detection of EEEV and WNV was used as the gold standard to confirm infection. All horses that tested positive for EEEV by RT-PCR also tested positive by IHC and ISH, except for 1 case that was false-negative by ISH. In contrast, all horses that tested positive for WNV by RT-PCR tested negative by IHC and only 2 horses tested positive by ISH. No false-positives were detected with either method for both viruses. Both IHC and ISH are highly specific and sensitive diagnostic methods to detect EEEV in equine FFPE brain tissues, although neither appear effective for the diagnosis of WNV in equine neurologic cases.

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

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    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.

  12. Targeted blockade in lethal West Nile virus encephalitis indicates a crucial role for very late antigen (VLA-4-dependent recruitment of nitric oxide-producing macrophages

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    Getts Daniel R

    2012-10-01

    Full Text Available Abstract Infiltration of Ly6Chi monocytes from the blood is a hallmark of viral encephalitis. In mice with lethal encephalitis caused by West Nile virus (WNV, an emerging neurotropic flavivirus, inhibition of Ly6Chi monocyte trafficking into the brain by anti-very late antigen (VLA-4 integrin antibody blockade at the time of first weight loss and leukocyte influx resulted in long-term survival of up to 60% of infected mice, with subsequent sterilizing immunity. This treatment had no effect on viral titers but appeared to be due to inhibition of Ly6Chi macrophage immigration. Although macrophages isolated from the infected brain induced WNV-specific CD4+ T-cell proliferation, T cells did not directly contribute to pathology, but are likely to be important in viral control, as antibody-mediated T-cell depletion could not reproduce the therapeutic benefit of anti-VLA-4. Instead, 70% of infiltrating inflammatory monocyte-derived macrophages were found to be making nitric oxide (NO. Furthermore, aminoguanidine-mediated inhibition of induced NO synthase activity in infiltrating macrophages significantly prolonged survival, indicating involvement of NO in the immunopathology. These data show for the first time the therapeutic effects of temporally targeting pathogenic NO-producing macrophages during neurotropic viral encephalitis.

  13. 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.

  14. 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.

  15. Identification of Avian and Hemoparasite DNA in Blood-Engorged Abdomens of Culex pipiens (Diptera; Culicidae) from a West Nile Virus Epidemic region in Suburban Chicago, Illinois.

    Science.gov (United States)

    Boothe, Emily; Medeiros, Matthew C I; Kitron, Uriel D; Brawn, Jeffrey D; Ruiz, Marilyn O; Goldberg, Tony L; Walker, Edward D; Hamer, Gabriel L

    2015-05-01

    Multiple mosquito-borne parasites cocirculate in nature and potentially interact. To understand the community of parasites cocirculating with West Nile virus (WNV), we screened the bloodmeal content of Culex pipiens L. mosquitoes for three common types of hemoparasites. Blood-fed Cx. pipiens were collected from a WNV-epidemic area in suburban Chicago, IL, from May to September 2005 through 2010. DNA was extracted from dissected abdomens and subject to PCR and direct sequencing to identify the vertebrate host. RNA was extracted from the head or thorax and screened for WNV using quantitative reverse transcriptase PCR. Seventy-nine engorged females with avian host origin were screened using PCR and amplicon sequencing for filarioid nematodes, Haemosporida, and trypanosomatids. Filarioid nematodes were identified in 3.8% of the blooded abdomens, Plasmodium sp. in 8.9%, Haemoproteus in 31.6%, and Trypanosoma sp. in 6.3%. The sequences from these hemoparasite lineages were highly similar to sequences from birds in prior studies in suburban Chicago. Overall, 50.6% of blood-fed Culex pipiens contained hemoparasite DNA in their abdomen, presumably from current or prior bloodmeals. Additionally, we detected hemoparasite DNA in the blooded abdomen of three of 10 Cx. pipiens infected with WNV. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Characterizing environmental risk factors for West Nile virus in Quebec, Canada, using clinical data in humans and serology in pet dogs.

    Science.gov (United States)

    Rocheleau, J P; Michel, P; Lindsay, L R; Drebot, M; Dibernardo, A; Ogden, N H; Fortin, A; Arsenault, J

    2017-10-01

    The identification of specific environments sustaining emerging arbovirus amplification and transmission to humans is a key component of public health intervention planning. This study aimed at identifying environmental factors associated with West Nile virus (WNV) infections in southern Quebec, Canada, by modelling and jointly interpreting aggregated clinical data in humans and serological data in pet dogs. Environmental risk factors were estimated in humans by negative binomial regression based on a dataset of 191 human WNV clinical cases reported in the study area between 2011 and 2014. Risk factors for infection in dogs were evaluated by logistic and negative binomial models based on a dataset including WNV serological results from 1442 dogs sampled from the same geographical area in 2013. Forested lands were identified as low-risk environments in humans. Agricultural lands represented higher risk environments for dogs. Environments identified as impacting risk in the current study were somewhat different from those identified in other studies conducted in north-eastern USA, which reported higher risk in suburban environments. In the context of the current study, combining human and animal data allowed a more comprehensive and possibly a more accurate view of environmental WNV risk factors to be obtained than by studying aggregated human data alone.

  17. 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

  18. 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.

  19. Rapid communication. New incursions of West Nile virus lineage 2 in Italy in 2013: the value of the entomological surveillance as early warning system

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    Mattia Calzolari

    2013-09-01

    Full Text Available West Nile virus (WNV is one of the most serious public health threats that Europe and the Mediterranean countries are currently facing. In Italy, WNV emerged in 1998 and has been circulating since 2008. To tackle its continuous incursions, Italian national and regional institutions set up a surveillance program, which includes the serological screening of sentinel horses, sentinel-chickens and backyard poultry flocks and the surveillance on all equine neurological cases, resident captured and wild dead birds, and vectors. This communication aims to assess the importance of the entomological surveillance program as an early warning system for WNV circulation. In the province of Modena, the circulation of WNV lineage 2 strains was first detected in pools of Culex pipiens on July the 3rd, 42 days prior to the onset of the first 2013 human WNV neuroinvasive case reported in the same province. Similarly in Veneto, WNV was first detected on July 3rd in a pool of Cx. pipiens collected in the province of Venezia. The first human neuroinvasive case in this region occurred in the Rovigo province on July the 24th, seven days after the detection of WNV lineage 2 in a mosquito pool collected in the same province. Up to the end of July 2013, WNV circulation was further detected in several other pools of Cx. pipiens mosquitoes collected in Emilia-Romagna, Veneto and Lombardia. According to the NS3 partial sequence alignments including all recent European and Italian Lineage 2 strains, the new circulating WNV lineage 2 strains share high nt homology with the Hungarian and with the previous lineage 2 strains isolated in Veneto and Sardegna in 2011 and 2012. These data provide a clear and practical demonstration of the relevance of a reliable entomological surveillance program to early detect WNV in Italy.

  20. Use of wild bird surveillance, human case data and GIS spatial analysis for predicting spatial distributions of West Nile virus in Greece.

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    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.

  1. Use of Wild Bird Surveillance, Human Case Data and GIS Spatial Analysis for Predicting Spatial Distributions of West Nile Virus in Greece

    Science.gov (United States)

    Valiakos, George; Papaspyropoulos, Konstantinos; Giannakopoulos, Alexios; Birtsas, Periklis; Tsiodras, Sotirios; Hutchings, Michael R.; Spyrou, Vassiliki; Pervanidou, Danai; Athanasiou, Labrini V.; Papadopoulos, Nikolaos; Tsokana, Constantina; Baka, Agoritsa; Manolakou, Katerina; Chatzopoulos, Dimitrios; Artois, Marc; Yon, Lisa; Hannant, Duncan; Petrovska, Liljana; Hadjichristodoulou, Christos; Billinis, Charalambos

    2014-01-01

    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. PMID:24806216

  2. A systems biology approach reveals that tissue tropism to West Nile virus is regulated by antiviral genes and innate immune cellular processes.

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    Mehul S Suthar

    2013-02-01

    Full Text Available The actions of the RIG-I like receptor (RLR and type I interferon (IFN signaling pathways are essential for a protective innate immune response against the emerging flavivirus West Nile virus (WNV. In mice lacking RLR or IFN signaling pathways, WNV exhibits enhanced tissue tropism, indicating that specific host factors of innate immune defense restrict WNV infection and dissemination in peripheral tissues. However, the immune mechanisms by which the RLR and IFN pathways coordinate and function to impart restriction of WNV infection are not well defined. Using a systems biology approach, we defined the host innate immune response signature and actions that restrict WNV tissue tropism. Transcriptional profiling and pathway modeling to compare WNV-infected permissive (spleen and nonpermissive (liver tissues showed high enrichment for inflammatory responses, including pattern recognition receptors and IFN signaling pathways, that define restriction of WNV replication in the liver. Assessment of infected livers from Mavs(-/- × Ifnar(-/- mice revealed the loss of expression of several key components within the natural killer (NK cell signaling pathway, including genes associated with NK cell activation, inflammatory cytokine production, and NK cell receptor signaling. In vivo analysis of hepatic immune cell infiltrates from WT mice demonstrated that WNV infection leads to an increase in NK cell numbers with enhanced proliferation, maturation, and effector action. In contrast, livers from Mavs(-/- × Ifnar(-/- infected mice displayed reduced immune cell infiltration, including a significant reduction in NK cell numbers. Analysis of cocultures of dendritic and NK cells revealed both cell-intrinsic and -extrinsic roles for the RLR and IFN signaling pathways to regulate NK cell effector activity. Taken together, these observations reveal a complex innate immune signaling network, regulated by the RLR and IFN signaling pathways, that drives tissue

  3. Host-feeding patterns of Culex pipiens and other potential mosquito vectors (Diptera: Culicidae) of West Nile virus (Flaviviridae) collected in Portugal.

    Science.gov (United States)

    Osório, Hugo Costa; Zé-Zé, Líbia; Alves, Maria João

    2012-05-01

    The host blood-feeding patterns of mosquito vectors affects the likelihood of human exposure to zoonotic pathogens, including West Nile Virus (family Flaviviridae, genus Flavivirus, WNV). In Portugal, data are unavailable regarding the blood-feeding habits of common mosquito species, including Culex pipiens L., considered the primary vector of WNV to humans. The sources of bloodmeals in 203 blood-fed mosquitoes of nine species collected from June 2007 to November 2010 in 34 Portuguese counties were analyzed by sequencing cytochrome-b partial fragments. Cx. pipiens was the most common species collected and successfully analyzed (n = 135/78). In addition, blood-fed females of the following species were analyzed: Ochlerotatus caspius Pallas (n = 20), Culex theileri Theobald (n = 16), Anopheles maculipennis s.l. Meigen (n = 10), Culiseta longiareolata Macquart (n = 7), Aedes aegypti L. (n = 6), Culex perexiguus Theobald (n = 3), Culiseta annulata Schrank (n = 3), and Ochlerotatus detritus Haliday (n = 3). The Cx. pipiens mosquitoes fed predominantly on birds (n = 55/78, 70.5%), with a high diversity of avian species used as hosts, although human blood was identified in 18 specimens (18/78, 23.1%). No significant differences were found between the host-feeding patterns of blood-fed Cx. pipiens collected in residential and nonresidential habitats. The occurrence of human derived blood meals and the presence of a mix avian-human bloodmeal accordingly suggest this species as a potential vector of WNV. Therefore, in Portugal, Cx. pipiens may play a role both in the avian-to-avian enzootic WNV cycle and in the avian-to-mammal transmission. In this context, the identity of Cx. pipiens (considering the forms molestus and pipiens) and the potential consequence on feeding behavior and WNV transmission are discussed.

  4. Use of wild bird surveillance, human case data and GIS spatial analysis for predicting spatial distributions of West Nile virus in Greece.

    Science.gov (United States)

    Valiakos, George; Papaspyropoulos, Konstantinos; Giannakopoulos, Alexios; Birtsas, Periklis; Tsiodras, Sotirios; Hutchings, Michael R; Spyrou, Vassiliki; Pervanidou, Danai; Athanasiou, Labrini V; Papadopoulos, Nikolaos; Tsokana, Constantina; Baka, Agoritsa; Manolakou, Katerina; Chatzopoulos, Dimitrios; Artois, Marc; Yon, Lisa; Hannant, Duncan; Petrovska, Liljana; Hadjichristodoulou, Christos; Billinis, Charalambos

    2014-01-01

    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.

  5. 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.

  6. Pathogenicity evaluation of twelve West Nile virus strains belonging to four lineages from five continents in a mouse model: discrimination between three pathogenicity categories.

    Science.gov (United States)

    Pérez-Ramírez, Elisa; Llorente, Francisco; Del Amo, Javier; Fall, Gamou; Sall, Amadou Alpha; Lubisi, Alison; Lecollinet, Sylvie; Vázquez, Ana; Jiménez-Clavero, Miguel Ángel

    2017-04-01

    Rodent models have been used extensively to study West Nile virus (WNV) infection because they develop severe neurological symptoms similar to those observed in human WNV neuroinvasive disease. Most of this research has focused on old lineage (L) 1 strains, while information about pathogenicity is lacking for the most recent L1 and L2 strains, as well as for newly defined lineages. In this study, 4-week-old Swiss mice were inoculated with a collection of 12 WNV isolates, comprising 10 old and recent L1 and L2 strains, the putative L6 strain from Malaysia and the proposed L7 strain Koutango (KOU). The intraperitoneal inoculation of 10-fold dilutions of each strain allowed the characterization of the isolates in terms of LD50, median survival times, ID50, replication in neural and extraneural tissues and antibody production. Based on these results, we classified the isolates in three groups: high virulence (all L1a strains, recent L2 strains and KOU), moderate virulence (B956 strain) and low virulence (Kunjin and Malaysian isolates). We determined that the inoculation of a single dose of 1000 p.f.u. would be sufficient to classify WNV strains by pathotype. We confirmed the enhanced virulence of the KOU strain with a high capacity to cause rapid systemic infection. We also corroborated that differences in pathogenicity among strains do not correlate with phylogenetic lineage or geographic origin, and confirmed that recent European and African WNV strains belonging to L1 and L2 are highly virulent and do not differ in their pathotype profile compared to the prototype NY99 strain.

  7. Association of spring-summer hydrology and meteorology with human West Nile virus infection in West Texas, USA, 2002-2016.

    Science.gov (United States)

    Ukawuba, Israel; Shaman, Jeffrey

    2018-04-04

    The emergence of West Nile virus (WNV) in the Western Hemisphere has motivated research into the processes contributing to the incidence and persistence of the disease in the region. Meteorology and hydrology are fundamental determinants of vector-borne disease transmission dynamics of a region. The availability of water influences the population dynamics of vector and host, while temperature impacts vector growth rates, feeding habits, and disease transmission potential. Characterization of the temporal pattern of environmental factors influencing WNV risk is crucial to broaden our understanding of local transmission dynamics and to inform efforts of control and surveillance. We used hydrologic, meteorological and WNV data from west Texas (2002-2016) to analyze the relationship between environmental conditions and annual human WNV infection. A Bayesian model averaging framework was used to evaluate the association of monthly environmental conditions with WNV infection. Findings indicate that wet conditions in the spring combined with dry and cool conditions in the summer are associated with increased annual WNV cases. Bayesian multi-model inference reveals monthly means of soil moisture, specific humidity and temperature to be the most important variables among predictors tested. Environmental conditions in March, June, July and August were the leading predictors in the best-fitting models. The results significantly link soil moisture and temperature in the spring and summer to WNV transmission risk. Wet spring in association with dry and cool summer was the temporal pattern best-describing WNV, regardless of year. Our findings also highlight that soil moisture may be a stronger predictor of annual WNV transmission than rainfall.

  8. Prevalence of chronic kidney disease and progression of disease over time among patients enrolled in the Houston West Nile virus cohort.

    Directory of Open Access Journals (Sweden)

    Melissa S Nolan

    Full Text Available INTRODUCTION: In experimental models of West Nile virus (WNV infection, animals develop chronic kidney infection with histopathological changes in the kidney up to 8-months post-infection. However, the long term pathologic effects of acute infection in humans are largely unknown. The purpose of this study was to assess renal outcomes following WNV infection, specifically the development of chronic kidney disease (CKD. METHODS: In a cohort of 139 study participants with a previous diagnosis of WNV infection, we investigated the prevalence of CKD using the Kidney Disease Outcomes Quality Initiative (KDOQI criteria based on the Modification of Diet in Renal Disease (MDRD formula and urinary abnormalities, and assessed various risk factors and biomarkers. RESULTS: Study participants were primarily male (60% and non-Hispanic white (86% with a mean age of 57 years. Most (83% were four to nine years post-infection at the time of this study. Based on the KDOQI definition, 40% of participants had evidence of CKD, with 10% having Stage III or greater and 30% having Stage I-II. By urinary dipstick testing, 26% of patients had proteinuria and 23% had hematuria. Plasma NGAL levels were elevated in 14% of participants while MCP-1 levels were increased in 12%. Over 1.5 years, the average change in eGFR was -3.71 mL/min/1.73 m(2. Only a history of Neuroinvasive WNV disease was independently associated with CKD following multivariate analysis. DISCUSSION: We found a high prevalence of CKD after long term follow-up in a cohort of participants previously infected with WNV. The majority of those with CKD are in Stage I-II indicating early stages of renal disease. Traditional risk factors were not associated with the presence of CKD in this population. Therefore, clinicians should regularly evaluate all patients with a history of WNV for evidence of CKD.

  9. Host cell killing by the West Nile Virus NS2B-NS3 proteolytic complex: NS3 alone is sufficient to recruit caspase-8-based apoptotic pathway

    International Nuclear Information System (INIS)

    Ramanathan, Mathura P.; Chambers, Jerome A.; Pankhong, Panyupa; Chattergoon, Michael; Attatippaholkun, Watcharee; Dang, Kesen; Shah, Neelima; Weiner, David B.

    2006-01-01

    The West Nile Virus (WNV) non-structural proteins 2B and 3 (NS2B-NS3) constitute the proteolytic complex that mediates the cleavage and processing of the viral polyprotein. NS3 recruits NS2B and NS5 proteins to direct protease and replication activities. In an effort to investigate the biology of the viral protease, we cloned cDNA encoding the NS2B-NS3 proteolytic complex from brain tissue of a WNV-infected dead crow, collected from the Lower Merion area (Merion strain). Expression of the NS2B-NS3 gene cassette induced apoptosis within 48 h of transfection. Electron microscopic analysis of NS2B-NS3-transfected cells revealed ultra-structural changes that are typical of apoptotic cells including membrane blebbing, nuclear disintegration and cytoplasmic vacuolations. The role of NS3 or NS2B in contributing to host cell apoptosis was examined. NS3 alone triggers the apoptotic pathways involving caspases-8 and -3. Experimental results from the use of caspase-specific inhibitors and caspase-8 siRNA demonstrated that the activation of caspase-8 was essential to initiate apoptotic signaling in NS3-expressing cells. Downstream of caspase-3 activation, we observed nuclear membrane ruptures and cleavage of the DNA-repair enzyme, PARP in NS3-expressing cells. Nuclear herniations due to NS3 expression were absent in the cells treated with a caspase-3 inhibitor. Expression of protease and helicase domains themselves was sufficient to trigger apoptosis generating insight into the apoptotic pathways triggered by NS3 from WNV

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

    OpenAIRE

    Humblet, M.; Vandeputte, S.; Fecher-Bourgeois, F.; Leonard, P.; Gosset, C.; Balenghien, Thomas; Durand, B.; Saegerman, C.

    2016-01-01

    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...

  11. 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

  12. Effect of serum heat-inactivation and dilution on detection of anti-WNV antibodies in mice by West Nile virus E-protein microsphere immunoassay.

    Directory of Open Access Journals (Sweden)

    Madhuri Namekar

    Full Text Available Immunopathogenesis studies employing West Nile virus (WNV mice model are important for the development of antivirals and vaccines against WNV. Since antibodies produced in mice early during WNV infection are essential for clearing virus from the periphery, it is important to detect early and persistent anti-WNV antibodies. ELISA and plaque reduction neutralization tests are traditionally used for detection of anti-WNV antibodies and WNV-neutralizing antibodies, respectively. Although these assays are sensitive and specific, they are expensive and time consuming. Microsphere immunoassays (MIA are sensitive, specific, allow for high throughput, are cost effective, require less time to perform than other methods, and require low serum volumes. Several assay parameters such as serum heat-inactivation (HI and dilution can alter WNV MIA sensitivity. We examined the effect of these parameters on WNV E-protein MIA (WNV E-MIA for the enhanced detection of anti-WNV IgM and IgG antibodies. WNV E-MIA was conducted using serial dilutions of HI and non-HI (NHI serum collected at various time points from mice inoculated with WNV. HI significantly enhanced detection of IgM and IgG antibodies as compared to NHI serum. WNV IgM and IgG antibodies in HI sera were detected earlier at day 3 and IgM antibodies persisted up to day 24 after infection. HI serum at 1∶20 dilution was found to be optimal for detection of both IgM and IgG antibodies as compared to higher-serum dilutions. Further, addition of exogenous complement to the HI serum decreased the WNV E-MIA sensitivity. These results suggest that serum-HI and optimal dilution enhance WNV E-MIA sensitivity by eliminating the complement interference, thereby detecting low-titer anti-WNV antibodies during early and late phases of infection. This improved MIA can also be readily employed for detection of low-titer antibodies for detection of other infectious agents and host proteins.

  13. Zika virus: a new arboviral public health problem.

    Science.gov (United States)

    Demir, Tulin; Kilic, Selcuk

    2016-11-01

    Zika virus (ZIKV) is a single-stranded RNA virus in the Flaviviridae family and transmitted to human through infected mosquitos (Aedes aegypti and Aedes albopictus). Virus is closely related with other flaviviruses; dengue virus, yellow fever virus, West Nile virus, and Japanese encephalitis virus phylogenetically. Due to the possible relationship between virus and clinical features including microcephaly, ventricule, and eye deformities, Guillain-Barre syndrome increases the interest on this virus gradually. Along with the vector-borne transmission, exposure via blood transfusion and sexual contact are further concerns. Since December 2015, CDC reported 440.000-1.300.000 possible cases in Brazil and as of 19 January 2016, El Salvador, Venezuela, Colombia, Brazil, Surinam, French Guana, Honduras, Mexico, and Panama are the countries with active epidemic. CDC recommends ZIKV screening for all pregnants including asymptomatic cases those living in the active epidemic areas. Recently, virus is detected in the USA and most European countries including UK, Netherlands, Denmark, Switzerland, and Italy as a travel-associated infection. Owing to the changing world with increased capabilities for transportation globally, this vector-borne infection represents a valuable marker for the ability of spreading of any infection from its original area that it was first seen. In this review, we summarized the up-to-date data and reports in terms of the importance of the ZIKV infection in the public health.

  14. Prevalencia de infección por el virus del Nilo Occidental en dos zoológicos del estado de Tabasco Prevalence of West Nile Virus infection in animals from two state zoos Tabasco

    Directory of Open Access Journals (Sweden)

    M Hidalgo-Martínez

    2008-02-01

    Full Text Available OBJETIVO: Determinar la prevalencia de infección por el virus del Nilo Occidental (VNO en animales, mosquitos y personal que labora en dos zoológicos del estado de Tabasco, en México. MATERIAL Y MÉTODOS: Con la utilización de ELISA de bloqueo se detectaron anticuerpos en sueros de animales: se buscó un fragmento del genoma del VNO por RT-PCR en el suero de animales, empleados y mosquitos. RESULTADOS: En el zoológico "La Venta" se encontró una seroprevalencia de 25.67% (19/74 en aves y de 85.71% (6/7 en reptiles. En el zoológico "Yum-Ká", 31.25% (50/160 de las aves y 34.48% (16/29, de los mamíferos, tuvieron anticuerpos contra el VNO. En un grupo de mosquitos (Culex quinquefasciatus se detectó el genoma del virus. CONCLUSIONES: La detección de anticuerpos contra el VNO en animales de ambos zoológicos y del genoma viral en mosquitos demuestra la presencia del virus, lo cual representa un riesgo potencial de infección para animales y humanos.OBJECTIVE: To determine the prevalence of West Nile Virus (WNV infection in animals, mosquitoes and employees from two zoos of Tabasco state, Mexico. MATERIAL AND METHODS: WNV antibodies were detected by blocking ELISA in serum samples from animals. Viral RNA was detected by RT-PCR from mosquitoes and serum samples from employees at "Yum-Ká" zoo. RESULTS: Seroprevalence in birds was 25.65% (19/74 and 85% (6/7 in reptiles from "La Venta" zoo. Thirty-one percent of birds (50/160 and 34.48% mammals (16/29 at the "Yum-Ká" zoo, were seropositive. All human serum samples from Yum-ká zoo were negative by RT-PCR. A pool of mosquitoes (Culex quinquefasciatus was positive for WNV. CONCLUSIONS: The presence of WNV antibodies in animals from both zoos and the detection of viral genome in mosquitoes demonstrate the presence of WNV in this region and indicates a potential risk of infection in animals and humans.

  15. An ImmunoSignature test distinguishes Trypanosoma cruzi, hepatitis B, hepatitis C and West Nile virus seropositivity among asymptomatic blood donors.

    Directory of Open Access Journals (Sweden)

    Michael Rowe

    2017-09-01

    Full Text Available The complexity of the eukaryotic parasite Trypanosoma (T. cruzi manifests in its highly dynamic genome, multi-host life cycle, progressive morphologies and immune-evasion mechanisms. Accurate determination of infection or Chagas' disease activity and prognosis continues to challenge researchers. We hypothesized that a diagnostic platform with higher ligand complexity than previously employed may hold value.We applied the ImmunoSignature Technology (IST for the detection of T. cruzi-specific antibodies among healthy blood donors. IST is based on capturing the information in an individual's antibody repertoire by exposing their peripheral blood to a library of >100,000 position-addressable, chemically-diverse peptides.Initially, samples from two Chagas cohorts declared positive or negative by bank testing were studied. With the first cohort, library-peptides displaying differential binding signals between T. cruzi sero-states were used to train an algorithm. A classifier was fixed and tested against the training-independent second cohort to determine assay performance. Next, samples from a mixed cohort of donors declared positive for Chagas, hepatitis B, hepatitis C or West Nile virus were assayed on the same library. Signals were used to train a single algorithm that distinguished all four disease states. As a binary test, the accuracy of predicting T. cruzi seropositivity by IST was similar, perhaps modestly reduced, relative to conventional ELISAs. However, the results indicate that information beyond determination of seropositivity may have been captured. These include the identification of cohort subclasses, the simultaneous detection and discerning of other diseases, and the discovery of putative new antigens.The central outcome of this study established IST as a reliable approach for specific determination of T. cruzi seropositivity versus disease-free individuals or those with other diseases. Its potential contribution for monitoring and

  16. The NILE data model

    International Nuclear Information System (INIS)

    Ogg, Michael; Ricciardi, Aleta; Amoroso, A.

    1996-01-01

    NILE is a multi-disciplinary project building a distributed computing environment for HEP. Nile will provide fault-tolerant, integrated access to processing and data resources for collaborators of the CLEO experiment, though the goals and principles are applicable to many domains. Nile currently has three main objectives: a realistic distributed system architecture design, the design of a robust data model, and a Fast-Track implementation providing a prototype design environment to be used by CLEO physicists. In this paper, we describe the Data Model, its design issues, and its interactions with the NILE System Architecture. (author)

  17. Mutation of mapped TIA-1/TIAR binding sites in the 3' terminal stem-loop of West Nile virus minus-strand RNA in an infectious clone negatively affects genomic RNA amplification.

    Science.gov (United States)

    Emara, Mohamed M; Liu, Hsuan; Davis, William G; Brinton, Margo A

    2008-11-01

    Previous data showed that the cellular proteins TIA-1 and TIAR bound specifically to the West Nile virus 3' minus-strand stem-loop [WNV3'(-)SL] RNA (37) and colocalized with flavivirus replication complexes in WNV- and dengue virus-infected cells (21). In the present study, the sites on the WNV3'(-)SL RNA required for efficient in vitro T-cell intracellular antigen-related (TIAR) and T-cell intracellular antigen-1 (TIA-1) protein binding were mapped to short AU sequences (UAAUU) located in two internal loops of the WNV3'(-)SL RNA structure. Infectious clone RNAs with all or most of the binding site nucleotides in one of the 3' (-)SL loops deleted or substituted did not produce detectable virus after transfection or subsequent passage. With one exception, deletion/mutation of a single terminal nucleotide in one of the binding sequences had little effect on the efficiency of protein binding or virus production, but mutation of a nucleotide in the middle of a binding sequence reduced both the in vitro protein binding efficiency and virus production. Plaque size, intracellular genomic RNA levels, and virus production progressively decreased with decreasing in vitro TIAR/TIA-1 binding activity, but the translation efficiency of the various mutant RNAs was similar to that of the parental RNA. Several of the mutant RNAs that inefficiently interacted with TIAR/TIA-1 in vitro rapidly reverted in vivo, indicating that they could replicate at a low level and suggesting that an interaction between TIAR/TIA-1 and the viral 3'(-)SL RNA is not required for initial low-level symmetric RNA replication but instead facilitates the subsequent asymmetric amplification of genome RNA from the minus-strand template.

  18. Presencia del virus del oeste del Nilo en el noreste de México Presence of west Nile virus in northeast Mexico

    Directory of Open Access Journals (Sweden)

    Ildefonso Fernández-Salas

    2007-06-01

    Full Text Available OBJETIVO: Detectar la presencia del virus del oeste del Nilo (VON en aves, equinos y seres humanos en el noreste de México. MATERIAL Y MÉTODOS: Se buscó en diferentes localidades del noreste de México la presencia de anticuerpos antivirus del oeste del Nilo (anti-VON en suero de 33 aves, 24 caballos y 237 personas mediante pruebas de ELISA durante el periodo de julio de 2003 a julio de 2006. En los sueros humanos se buscó también el RNA-VON mediante RT-PCR. RESULTADOS: Se encontraron tres aves seropositivas y 15 equinos. En el hombre, 40% de los sueros fue positivo para anticuerpos IgG y ninguno para anticuerpos IgM. CONCLUSIONES: El VON se encuentra activo en México y se suma a otras enfermedades emergentes transmitidas por vectores que representan un reto a la investigación y a los programas de prevención.OBJECTIVE: To investigate the presence of WNV in birds, horses and humans in northeast Mexico. MATERIAL AND METHODS: Serum samples from 33 birds, 24 horses and 237 humans were screened by ELISA for Anti-WNV antibodies. Human serum samples were also screened for WNV RNA using an RT-PCR assay. RESULTS: Positive sera were found in three birds and 15 horses. Forty percent of the human serum samples were positive for IgG antibodies and 0% for IgM antibodies and viral RNA. CONCLUSIONS: The results of this study show that WNV is present in northeast Mexico and it is a new emergent infectious agent that represents a challenge for research and prevention programs in Mexico.

  19. [Immigration to Venezuela].

    Science.gov (United States)

    Picouet, M; Pellegrino, A; Papail, J

    1986-11-01

    Immigration to Venezuela is examined using census data with the focus on the period 1971-1981. A brief overview of trends since the beginning of the twentieth century is first presented. The analysis indicates that "immigration to Venezuela is clearly of a short-term nature. Flows follow job opportunities and adjust to the labour market and to the financial capacity of the exchange market. The large increase of migratory movements to Venezuela in the 1970's is characterized by a diversification of their places of origin and by a greater instability. To a large extent, the migrants are illegal, especially those coming from Colombia and the Caribbean islands. Because of the crisis of the early 1980's, which is now worsened by the down trend of both oil prices and the U.S. dollar, Venezuela has become less attractive to immigrants, particularly from neighbouring countries." The authors observe that migrants in Venezuela are not well integrated and may depart, disrupting the labor supply in certain technical and specialized occupations (SUMMARY IN ENG AND SPA) excerpt

  20. Bajo impacto de la infección silente por el virus de la hepatitis B en la incidencia de hepatitis postransfusional en Venezuela

    Directory of Open Access Journals (Sweden)

    Gutiérrez Cristina

    2001-01-01

    Full Text Available Objetivo. Detectar la presencia de ADN del VHB en sueros de donantes de sangre negativos en las pruebas de los marcadores serológicos de hepatitis B empleados en el tamizaje, con el fin de evaluar el impacto de la infección silente por VHB sobre la incidencia de hepatitis B postransfusional en Venezuela. Métodos. Los sueros de 2 075 donantes de sangre negativos en las pruebas de los marcadores serológicos pesquisados en bancos de sangre venezolanos fueron analizados en 53 muestras, compuestas por la mezcla de 25-50 donaciones (0,5-1,0 mL de cada suero. Estas fueron sometidos a ultracentrifugación previa a la extracción del ADN viral por el método de proteinasa K-fenol-cloroformo. Resultados. En estas mezclas de sueros no se detectó ADN del VHB en ninguno de dos ensayos anidados de reacción en cadena de la polimerasa, mediante cebadores altamente conservados de las regiones que codifican el antígeno de superficie y de la cápside virales. Se observaron niveles normales de aminotransferasas en 98% de 200 sueros evaluados. Conclusiones. Estos resultados sugieren que el riesgo de adquirir hepatitis B postransfusional en Venezuela es bajo.

  1. LDC nuclear power: Venezuela

    International Nuclear Information System (INIS)

    Roche, M.

    1982-01-01

    Venezuela had an aggressive nuclear program when it was under a dictatorship in the 1950s, but it is currently assuming a wait-and-see stance. The country has one small research reactor, but it may have a reactor on-line in the mid-1990s. CONADIN, Venezuela's nuclear energy planning agency, has commissioned feasibility studies and requested proposals for a reactor-siting survey. A recent study for the Venezuelan state oil company suggests tha a natural-uranium, gas-cooled reactor could provide process steam to extract oil from the bituminous tar sands of the Orinoco Basin. Venezuela is also exploring for uranium reserves. 23 references, 1 figure, 2 tables

  2. Venezuela and China

    DEFF Research Database (Denmark)

    Agustin, Oscar Garcia

    2016-01-01

    of a political and economic model which can inspire or be followed by other countries. Although China's influence and increasing power in Venezuela is unquestionable in economic terms, the Venezuelan government uses its agreements with China strategically to legitimate its policies, in the name of a South...... draws on this context of 'interdependent hegemony' to explore the existing relationship between Venezuela, as a swing state, and China, as one of the Big Three global powers. Particularly, I focus on Venezuelan efforts to develop, at the domestic and regional level, a counterhegemonic political project...

  3. West Nile virus (linie 2) v komárech na jižní Moravě – očekávání prvních autochtonních lidských případů

    Czech Academy of Sciences Publication Activity Database

    Rudolf, Ivo; Blažejová, Hana; Šebesta, Oldřich; Mendel, Jan; Peško, Juraj; Betášová, Lenka; Straková, Petra; Šikutová, Silvie; Hubálek, Zdeněk

    2018-01-01

    Roč. 67, č. 1 (2018), s. 44-46 ISSN 1210-7913 R&D Projects: GA ČR(CZ) GA16-20054S Grant - others:AV ČR + JMK + město Břeclav(CZ) R200931601 Institutional support: RVO:68081766 Keywords : West Nile virus * arboviruses * emerging zoonoses * mosquitoes * Culex pipiens * Culex modestus Subject RIV: EE - Microbiology, Virology OBOR OECD: Virology Impact factor: 0.500, year: 2016

  4. Venezuela - energy situation 1982

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    The energy situation of Venezuela is reviewed on the basis of some relevant data. Its energy policy is commented on, and developments in electric power generation are described as well as the trends observed for the various energy sources. Figures are given on external trade and on the balance of payments.

  5. Baja prevalencia de la infección por el virus de la hepatitis C en una población de reclusos, Maracaibo, Venezuela

    Directory of Open Access Journals (Sweden)

    Francisca Monsalve

    2009-12-01

    Conclusiones. La prevalencia de la infección por el virus de la hepatitis C en esta población fue baja, lo que evidencia la baja circulación del virus en el reclusorio. El principal factor de riesgo para la adquisición de la infección, al parecer, es el uso de drogas intravenosas.

  6. Altered Protein Networks and Cellular Pathways in Severe West Nile Disease in Mice

    NARCIS (Netherlands)

    C. Fraisier (Christophe); L. Camoin (Luc); S.M. Lim (Stephanie); M. Bakli (Mahfoud); M. Belghazi (Maya); P. Fourquet (Patrick); S. Granjeaud (Samuel); A.D.M.E. Osterhaus (Albert); P. Koraka (Penelope); B.E.E. Martina (Byron); L. Almeras (Lionel)

    2013-01-01

    textabstractBackground:The recent West Nile virus (WNV) outbreaks in developed countries, including Europe and the United States, have been associated with significantly higher neuropathology incidence and mortality rate than previously documented. The changing epidemiology, the constant risk of

  7. West Nile Flavivirus Polioencephalomyelitis in a harbor seal (Phoca vitulina).

    Science.gov (United States)

    Del Piero, F; Stremme, D W; Habecker, P L; Cantile, C

    2006-01-01

    A 12-year-old male harbor seal presented with progressive signs of neurologic dysfunction including head tremors, muzzle twitching, clonic spasms, and weakness. Lesions included polioencephalomyelitis with glial nodules, spheroids, neuronophagia, ring hemorrhages, and a few neutrophils. Neurons, fibers, and glial nodules were multifocally colonized with intracytoplasmic West Nile flavivirus antigens that were demonstrated using indirect immunohistochemical analysis. Flavivirus on cultured cells also was isolated and was identified by use of monoclonal antibodies and reverse transcriptase-polymerase chain reaction analysis. Clinical signs of disease and lesion morphology and distribution were similar to those of equine West Nile virus infection. Similar to horses, alpacas, humans, dogs, and reptiles, seals can be dead-end hosts of West Nile virus.

  8. Zika virus infection: a public health emergency!

    OpenAIRE

    Qureshi, Muhammad Salman Haider; Qureshi, Bakhtawar Wajeeha; Khan, Ramsha

    2017-01-01

    Zika virus belongs to the family of Flaviviridae. The Flaviviridae family also includes other human pathogens like West Nile virus (WNV), Yellow fever virus (YFV), mosquito transmitted Dengue virus (DENV), Tick borne encephalitic virus (TBEV) and Japanese encephalitis virus (JEV). Zika virus is a mosquito-borne disease and is transmitted by Aedes aegypti mosquito.

  9. 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.

  10. Venezuela takes responsabilidad

    International Nuclear Information System (INIS)

    Hunter, D.

    1992-01-01

    No federal government officials showed up at the Oct. 29 ceremony to lauch the Responsabilidad Integral program of Asoquim, the Venezuelan chemical industry association. But that did not discourage industry representatives. Industry has tried to keep the Ministry of Environment Affairs involved as much as possible, says Danay Zoppi de Perez, corporate v.p. with Grupo Quimico. But industry was proud to be doing it anyway, despite the absence of government. It's a private, proactive initiative. Asoquim's program is based on the six Responsible Care codes. At the ceremony, 56 companies from Asoquim's membership of 150, which represents 90% of chemicals production in the country, signed on. Signatories include stateowned Petroquimica de Venezuela (Pequiven), domestic private-sector firms, and most of the multinationls operating in Venezuela. The ceremony drew officials from the fire service and civil defense authorities who have to deal with spills and accidents

  11. Venezuela ups the ante

    International Nuclear Information System (INIS)

    Collitt, Raymond.

    1997-01-01

    Strong performances by small and medium sized oil companies in Venezuela have contributed to the success of its oil industry. This paper considers the historical progress of the industry since its nationalisation twenty-one years ago, charting its attractiveness to investors and plans for expansion. Its very success has brought the Venezuelan oil industry into conflict with OPEC's quota system, which it argues, needs to be charged. (UK)

  12. Estimating Venezuelas Latent Inflation

    OpenAIRE

    Juan Carlos Bencomo; Hugo J. Montesinos; Hugo M. Montesinos; Jose Roberto Rondo

    2011-01-01

    Percent variation of the consumer price index (CPI) is the inflation indicator most widely used. This indicator, however, has some drawbacks. In addition to measurement errors of the CPI, there is a problem of incongruence between the definition of inflation as a sustained and generalized increase of prices and the traditional measure associated with the CPI. We use data from 1991 to 2005 to estimate a complementary indicator for Venezuela, the highest inflation country in Latin America. Late...

  13. HYDROCARBONS RESERVES IN VENEZUELA

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Cruz, D.J.

    2007-07-01

    Venezuela is an important player in the energy world, because of its hydrocarbons reserves. The process for calculating oil and associated gas reserves is described bearing in mind that 90% of the gas reserves of Venezuela are associated to oil. Likewise, an analysis is made of the oil reserves figures from 1975 to 2003. Reference is also made to inconsistencies found by international experts and the explanations offered in this respect by the Ministry of Energy and Petroleum (MENPET) and Petroleos de Venezuela (PDVSA) regarding the changes that took place in the 1980s. In turn, Hubbert's Law is explained to determine peak production of conventional oil that a reservoir or field will reach, as well as its relationship with remaining reserves. Emphasis is placed on the interest of the United Nations on this topic. The reserves of associated gas are presented along with their relationship with the different crude oils that are produced and with injected gas, as well as with respect to the possible changes that would take place in the latter if oil reserves are revised. Some recommendations are submitted so that the MENPET starts preparing the pertinent policies ruling reserves. (auth)

  14. Country watch: Venezuela.

    Science.gov (United States)

    Koch, R

    1996-01-01

    Since 1990, ACCSI has worked to safeguard the rights of people living with HIV/AIDS in Venezuela. The Pan American Health Organization (PAHO) had recognized ACCSI's program by 1992, enabling the nongovernmental organization (NGO) to establish fixed office hours during which it can receive clients. ACCSI does not distinguish between people living with HIV/AIDS and others, but considers it important to regulate AIDS as a public health issue within the context of human rights and ethics. Almost all of the Legal Office's initial cases were related to discrimination in the workplace, health centers, and educational institutions, but the ACCSI now also addresses family problems related to adoption, insurance, and inheritance, among others. To cope with the increase in service caseload, services have been extended through collaboration with specialized organizations concerned with human rights, women, children, prisons, and indigenous people. ACCSI influences governmental policy-making through its participation in the National AIDS Program. Moreover, ACCSI's networking activities ensure that the topic of HIV/AIDS and human rights is now always included in seminars and conferences in Venezuela, even when they are concerned with sexually transmitted diseases or other medical issues. Almost every time the press report upon AIDS, they consult the NGO. Everyday more people in Venezuela are standing up for their rights and denouncing discrimination against people infected with HIV.

  15. Spatio-Temporal Distribution of Vector-Host Contact (VHC) Ratios and Ecological Niche Modeling of the West Nile Virus Mosquito Vector, Culex quinquefasciatus, in the City of New Orleans, LA, USA.

    Science.gov (United States)

    Sallam, Mohamed F; Michaels, Sarah R; Riegel, Claudia; Pereira, Roberto M; Zipperer, Wayne; Lockaby, B Graeme; Koehler, Philip G

    2017-08-08

    The consistent sporadic transmission of West Nile Virus (WNV) in the city of New Orleans justifies the need for distribution risk maps highlighting human risk of mosquito bites. We modeled the influence of biophysical and socioeconomic metrics on the spatio-temporal distributions of presence/vector-host contact (VHC) ratios of WNV vector, Culex quinquefasciatus , within their flight range . Biophysical and socioeconomic data were extracted within 5-km buffer radii around sampling localities of gravid female Culex quinquefasciatus . The spatio-temporal correlations between VHC data and 33 variables, including climate, land use-land cover (LULC), socioeconomic, and land surface terrain were analyzed using stepwise linear regression models (RM). Using MaxEnt, we developed a distribution model using the correlated predicting variables. Only 12 factors showed significant correlations with spatial distribution of VHC ratios ( R ² = 81.62, p < 0.01). Non-forested wetland (NFWL), tree density (TD) and residential-urban (RU) settings demonstrated the strongest relationship. The VHC ratios showed monthly environmental resilience in terms of number and type of influential factors. The highest prediction power of RU and other urban and built up land (OUBL), was demonstrated during May-August. This association was positively correlated with the onset of the mosquito WNV infection rate during June. These findings were confirmed by the Jackknife analysis in MaxEnt and independently collected field validation points. The spatial and temporal correlations of VHC ratios and their response to the predicting variables are discussed.

  16. Vaccination of mice using the West Nile virus E-protein in a DNA prime-protein boost strategy stimulates cell-mediated immunity and protects mice against a lethal challenge.

    Directory of Open Access Journals (Sweden)

    Marina De Filette

    Full Text Available West Nile virus (WNV is a mosquito-borne flavivirus that is endemic in Africa, the Middle East, Europe and the United States. There is currently no antiviral treatment or human vaccine available to treat or prevent WNV infection. DNA plasmid-based vaccines represent a new approach for controlling infectious diseases. In rodents, DNA vaccines have been shown to induce B cell and cytotoxic T cell responses and protect against a wide range of infections. In this study, we formulated a plasmid DNA vector expressing the ectodomain of the E-protein of WNV into nanoparticles by using linear polyethyleneimine (lPEI covalently bound to mannose and examined the potential of this vaccine to protect against lethal WNV infection in mice. Mice were immunized twice (prime--boost regime with the WNV DNA vaccine formulated with lPEI-mannose using different administration routes (intramuscular, intradermal and topical. In parallel a heterologous boost with purified recombinant WNV envelope (E protein was evaluated. While no significant E-protein specific humoral response was generated after DNA immunization, protein boosting of DNA-primed mice resulted in a marked increase in total neutralizing antibody titer. In addition, E-specific IL-4 T-cell immune responses were detected by ELISPOT after protein boost and CD8(+ specific IFN-γ expression was observed by flow cytometry. Challenge experiments using the heterologous immunization regime revealed protective immunity to homologous and virulent WNV infection.

  17. 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.

  18. Malaria control and elimination, Venezuela, 1800s –1970s.

    Science.gov (United States)

    Griffing, Sean M; Villegas, Leopoldo; Udhayakumar, Venkatachalam

    2014-10-01

    Venezuela had the highest number of human malaria cases in Latin American before 1936. During 1891–1920,malaria was endemic to >600,000 km2 of this country; malaria death rates led to major population decreases during 1891–1920. No pathogen, including the influenza virus that caused the 1918 pandemic, caused more deaths than malaria during 1905–1945. Early reports of malaria eradication in Venezuela helped spark the world's interest in global eradication. We describe early approaches to malaria epidemiology in Venezuela and how this country developed an efficient control program and an approach to eradication.Arnoldo Gabaldón was a key policy maker during this development process. He directed malaria control in Venezuela from the late 1930s to the end of the 1970s and contributed to malaria program planning of the World Health Organization.We discuss how his efforts helped reduce the incidence of malaria in Venezuela and how his approach diverged from World Health Organization guidelines.

  19. Malaria Control and Elimination,1 Venezuela, 1800s–1970s

    Science.gov (United States)

    Villegas, Leopoldo; Udhayakumar, Venkatachalam

    2014-01-01

    Venezuela had the highest number of human malaria cases in Latin American before 1936. During 1891–1920, malaria was endemic to >600,000 km2 of this country; malaria death rates led to major population decreases during 1891–1920. No pathogen, including the influenza virus that caused the 1918 pandemic, caused more deaths than malaria during 1905–1945. Early reports of malaria eradication in Venezuela helped spark the world’s interest in global eradication. We describe early approaches to malaria epidemiology in Venezuela and how this country developed an efficient control program and an approach to eradication. Arnoldo Gabaldón was a key policy maker during this development process. He directed malaria control in Venezuela from the late 1930s to the end of the 1970s and contributed to malaria program planning of the World Health Organization. We discuss how his efforts helped reduce the incidence of malaria in Venezuela and how his approach diverged from World Health Organization guidelines.

  20. Interaction between the cellular protein eEF1A and the 3'-terminal stem-loop of West Nile virus genomic RNA facilitates viral minus-strand RNA synthesis.

    Science.gov (United States)

    Davis, William G; Blackwell, Jerry L; Shi, Pei-Yong; Brinton, Margo A

    2007-09-01

    RNase footprinting and nitrocellulose filter binding assays were previously used to map one major and two minor binding sites for the cell protein eEF1A on the 3'(+) stem-loop (SL) RNA of West Nile virus (WNV) (3). Base substitutions in the major eEF1A binding site or adjacent areas of the 3'(+) SL were engineered into a WNV infectious clone. Mutations that decreased, as well as ones that increased, eEF1A binding in in vitro assays had a negative effect on viral growth. None of these mutations affected the efficiency of translation of the viral polyprotein from the genomic RNA, but all of the mutations that decreased in vitro eEF1A binding to the 3' SL RNA also decreased viral minus-strand RNA synthesis in transfected cells. Also, a mutation that increased the efficiency of eEF1A binding to the 3' SL RNA increased minus-strand RNA synthesis in transfected cells, which resulted in decreased synthesis of genomic RNA. These results strongly suggest that the interaction between eEF1A and the WNV 3' SL facilitates viral minus-strand synthesis. eEF1A colocalized with viral replication complexes (RC) in infected cells and antibody to eEF1A coimmunoprecipitated viral RC proteins, suggesting that eEF1A facilitates an interaction between the 3' end of the genome and the RC. eEF1A bound with similar efficiencies to the 3'-terminal SL RNAs of four divergent flaviviruses, including a tick-borne flavivirus, and colocalized with dengue virus RC in infected cells. These results suggest that eEF1A plays a similar role in RNA replication for all flaviviruses.

  1. Laboratory Transmission of Japanese Encephalitis, West Nile Viruses and Getah by Mosquitoes (Diptera:Culicidae) Collected Near Camp Greaves, Gyeonggi Province, Republic of Korea, 2003

    National Research Council Canada - National Science Library

    Turell, Michael J; Mores, Christopher N; Dohm, David J; Lee, Won-Ja; Kim, Heung-Chul; Klein, Terry A

    2006-01-01

    ...% when allowed to feed on chickens with viremias of approximately 107 plaque-forming units (PFU) of virus/ml blood. In contrast, Cx. tritaeniorhynchus were significantly more susceptible to JEV or GETV...

  2. Laboratory Transmission of Japanese Encephalitis and West Nile Viruses by Molestus Form of Culex pipiens (Diptera: Culicidae) Collected in Uzbekistan in 2004

    National Research Council Canada - National Science Library

    Turell, M. J; Mores, C. N; Dohm, D. J; Komilov, N; Paragas, J; Lee, J. S; Shermuhemedova, D; Endy, T. P; Kodirov, A; Khodjaev, S

    2006-01-01

    ... (family Flaviviridae, genus Flavivirus, WNV) viruses under laboratory conditions. These molestus were highly competent laboratory vectors of WNV, with infection and dissemination rates of 96 and 81%, respectively. Approximately 75...

  3. Venezuela: Un perfil general.

    OpenAIRE

    Quevedo, Rafael Isidro

    2003-01-01

    1.- Artículos Cartay, Rafael. "Los productos típicos y su reglamentación. Una tentativa de aplicación de la denominación de origen al cacao venezolano" Kalvatchev, Zlatko; Garzaro, Domingo; Guerra Cedezo, Franklin. "Theobroma Cacao L.: Un nuevo enfoque para nutrición y salud" Anido, Daniel; Gutiérrez, Alejandro. "La demanda de las calorías en Venezuela 1970-1995: Algunas evidencias empíricas" Molina, Luisa Elena. "Notas sobre la situación de la producción primaria de arroz en Ven...

  4. Diabetes Care in Venezuela.

    Science.gov (United States)

    Nieto-Martínez, Ramfis; González-Rivas, Juan P; Lima-Martínez, Marcos; Stepenka, Victoria; Rísquez, Alejandro; Mechanick, Jeffrey I

    2015-01-01

    The incidence of type 2 diabetes (T2D) and its economic burden have increased in Venezuela, posing difficult challenges in a country already in great turmoil. The aim of this study was to review the prevalence, causes, prevention, management, health policies, and challenges for successful management of diabetes and its complications in Venezuela. A comprehensive literature review spanning 1960 to 2015 was performed. Literature not indexed also was reviewed. The weighted prevalence of diabetes and prediabetes was estimated from published regional and subnational population-based studies. Diabetes care strategies were analyzed. In Venezuela, the weighted prevalence of diabetes was 7.7% and prediabetes was 11.2%. Diabetes was the fifth leading cause of death (7.1%) in 2012 with the mortality rate increasing 7% per year from 1990 to 2012. In 2012, cardiovascular disease and diabetes together were the leading cause of disability-adjusted life years.T2D drivers are genetic, epigenetic, and lifestyle, including unhealthy dietary patterns and physical inactivity. Obesity, insulin resistance, and metabolic syndrome are present at lower cutoffs for body mass index, homeostatic model assessment, and visceral or ectopic fat, respectively. Institutional programs for early detection and/or prevention of T2D have not been established. Most patients with diabetes (∼87%) are cared for in public facilities in a fragmented health system. Local clinical practice guidelines are available, but implementation is suboptimal and supporting information is limited. Strategies to improve diabetes care in Venezuela include enhancing resources, reducing costs, improving education, implementing screening (using Latin America Finnish Diabetes Risk Score), promoting diabetes care units, avoiding insulin levels as diagnostic tool, correct use of oral glucose tolerance testing and metformin as first-line T2D treatment, and reducing health system fragmentation. Use of the Venezuelan adaptation of

  5. Undocumented migration to Venezuela.

    Science.gov (United States)

    Van Roy, R

    1984-01-01

    "In 1980 Venezuela took...steps to regularize the undocumented migrant population. While the number responding to the amnesty was small relative to expectations, the majority of illegals appeared to have regularized their status. For the first time it was possible to assess objectively the characteristics of the undocumented population. Moreover, the problem of illegal migrants seems to have been temporarily solved, a result of both the amnesty and the country's declining economic activity." Topics covered in the present article include the nationality, geographic distribution, sex and age distribution, educational status, and occupations of undocumented migrants. excerpt

  6. Cleavage preference distinguishes the two-component NS2B-NS3 serine proteinases of Dengue and West Nile viruses.

    Science.gov (United States)

    Shiryaev, Sergey A; Kozlov, Igor A; Ratnikov, Boris I; Smith, Jeffrey W; Lebl, Michal; Strongin, Alex Y

    2007-02-01

    Regulated proteolysis of the polyprotein precursor by the NS2B-NS3 protease is required for the propagation of infectious virions. Unless the structural and functional parameters of NS2B-NS3 are precisely determined, an understanding of its functional role and the design of flaviviral inhibitors will be exceedingly difficult. Our objectives were to define the substrate recognition pattern of the NS2B-NS3 protease of West Nile and Dengue virises (WNV and DV respectively). To accomplish our goals, we used an efficient, 96-well plate format, method for the synthesis of 9-mer peptide substrates with the general P4-P3-P2-P1-P1'-P2'-P3'-P4'-Gly structure. The N-terminus and the constant C-terminal Gly of the peptides were tagged with a fluorescent tag and with a biotin tag respectively. The synthesis was followed by the proteolytic cleavage of the synthesized, tagged peptides. Because of the strict requirement for the presence of basic amino acid residues at the P1 and the P2 substrate positions, the analysis of approx. 300 peptide sequences was sufficient for an adequate representation of the cleavage preferences of the WNV and DV proteinases. Our results disclosed the strict substrate specificity of the WNV protease for which the (K/R)(K/R)R/GG amino acid motifs was optimal. The DV protease was less selective and it tolerated well the presence of a number of amino acid residue types at either the P1' or the P2' site, as long as the other position was occupied by a glycine residue. We believe that our data represent a valuable biochemical resource and a solid foundation to support the design of selective substrates and synthetic inhibitors of flaviviral proteinases.

  7. Sentinel surveillance of influenza-like illness in two hospitals in Maracay, Venezuela: 2006-2010.

    Science.gov (United States)

    Comach, Guillermo; Teneza-Mora, Nimfa; Kochel, Tadeusz J; Espino, Carlos; Sierra, Gloria; Camacho, Daria E; Laguna-Torres, V Alberto; Garcia, Josefina; Chauca, Gloria; Gamero, Maria E; Sovero, Merly; Bordones, Slave; Villalobos, Iris; Melchor, Angel; Halsey, Eric S

    2012-01-01

    Limited information exists on the epidemiology of acute febrile respiratory illnesses in tropical South American countries such as Venezuela. The objective of the present study was to examine the epidemiology of influenza-like illness (ILI) in two hospitals in Maracay, Venezuela. We performed a prospective surveillance study of persons with ILI who presented for care at two hospitals in Maracay, Venezuela, from October 2006 to December 2010. A respiratory specimen and clinical information were obtained from each participant. Viral isolation and identification with immunofluorescent antibodies and molecular methods were employed to detect respiratory viruses such as adenovirus, influenza A and B, parainfluenza, and respiratory sincytial virus, among others. There were 916 participants in the study (median age: 17 years; range: 1 month--86 years). Viruses were identified in 143 (15.6%) subjects, and one participant was found to have a co-infection with more than one virus. Influenza viruses, including pandemic H1N1 2009, were the most frequently detected pathogens, accounting for 67.4% (97/144) of the viruses detected. Adenovirus (15/144), parainfluenza virus (13/144), and respiratory syncytial virus (11/144) were also important causes of ILI in this study. Pandemic H1N1 2009 virus became the most commonly isolated influenza virus during its initial appearance in 2009. Two waves of the pandemic were observed: the first which peaked in August 2009 and the second--higher than the preceding - that peaked in October 2009. In 2010, influenza A/H3N2 re-emerged as the most predominant respiratory virus detected. Influenza viruses were the most commonly detected viral organisms among patients with acute febrile respiratory illnesses presenting at two hospitals in Maracay, Venezuela. Pandemic H1N1 2009 influenza virus did not completely replace other circulating influenza viruses during its initial appearance in 2009. Seasonal influenza A/H3N2 was the most common influenza

  8. A recombinant novirhabdovirus presenting at the surface the E Glycoprotein from West Nile Virus (WNV is immunogenic and provides partial protection against lethal WNV challenge in BALB/c mice.

    Directory of Open Access Journals (Sweden)

    Angella Nzonza

    Full Text Available West Nile Virus (WNV is a zoonotic mosquito-transmitted flavivirus that can infect and cause disease in mammals including humans. Our study aimed at developing a WNV vectored vaccine based on a fish Novirhabdovirus, the Viral Hemorrhagic Septicemia virus (VHSV. VHSV replicates at temperatures lower than 20°C and is naturally inactivated at higher temperatures. A reverse genetics system has recently been developed in our laboratory for VHSV allowing the addition of genes in the viral genome and the recovery of the respective recombinant viruses (rVHSV. In this study, we have generated rVHSV vectors bearing the complete WNV envelope gene (EWNV (rVHSV-EWNV or fragments encoding E subdomains (either domain III alone or domain III fused to domain II (rVHSV-DIIIWNV and rVHSV-DII-DIIIWNV, respectively in the VHSV genome between the N and P cistrons. With the objective to enhance the targeting of the EWNV protein or EWNV-derived domains to the surface of VHSV virions, Novirhadovirus G-derived signal peptide and transmembrane domain (SPG and TMG were fused to EWNV at its amino and carboxy termini, respectively. By Western-blot analysis, electron microscopy observations or inoculation experiments in mice, we demonstrated that both the EWNV and the DIIIWNV could be expressed at the viral surface of rVHSV upon addition of SPG. Every constructs expressing EWNV fused to SPG protected 40 to 50% of BALB/cJ mice against WNV lethal challenge and specifically rVHSV-SPGEWNV induced a neutralizing antibody response that correlated with protection. Surprisingly, rVHSV expressing EWNV-derived domain III or II and III were unable to protect mice against WNV challenge, although these domains were highly incorporated in the virion and expressed at the viral surface. In this study we demonstrated that a heterologous glycoprotein and non membrane-anchored protein, can be efficiently expressed at the surface of rVHSV making this approach attractive to develop new vaccines

  9. 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

  10. Mosquito (Diptera: Culicidae) surveillance for arboviruses in an area endemic for West Nile (Lineage Rabensburg) and Ťahyňa viruses in central Europe

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk; Rudolf, Ivo; Bakonyi, T.; Kazdová, Klára; Halouzka, Jiří; Šebesta, Oldřich; Šikutová, Silvie; Juřicová, Zina; Nowotny, N.

    2010-01-01

    Roč. 47, č. 3 (2010), s. 466-472 ISSN 0022-2585 EU Projects: European Commission(XE) 10284 - EDEN Institutional research plan: CEZ:AV0Z60930519 Keywords : California group viruses * Flavivirus * Orthobunyavirus Subject RIV: EE - Microbiology, Virology Impact factor: 1.925, year: 2010

  11. 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, Dennis; Hofmeister, Erik K.; Atkinson, C.T.; Porter, R.E.; Dusek, Robert 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.

  12. Petrochemical development in Venezuela

    International Nuclear Information System (INIS)

    Volkenborn, A.

    1997-01-01

    This presentation highlighted the evolution of the petrochemical industry in Venezuela. Comparative advantages for the industry such as (1) abundant low cost energy, (2) attractive geographical position, (3) good infrastructure, (4) skilled, low cost labour force, and (5) regional integration, were reviewed. A summary of national production, refining, and marketing facts for petrochemicals, coal, orimulsion, and marine transportation were presented, along with financial information concerning revenues from sales, and profits and investments. Future plans to maximize the creation of value for the nation through increased oil production and partial privatization of state petroleum enterprises, were reviewed. The current state and future plans for focused development of fertilizers, olefins and olefin derivatives, and methanol products were outlined. Production statistics for three large petrochemical complexes, - El Tablazo, Moron and Jose - were also presented. 9 figs

  13. Mochima, estado Sucre (Venezuela

    Directory of Open Access Journals (Sweden)

    Karen Elisa Requena Mago

    2005-01-01

    Full Text Available En tiempos de recesión, los expertos nos bombardean con cifras relacionadas a la caída del producto interno bruto, al desempleo, entre otras. Dada la situación que presenta hoy en día Venezuela, aunado a la alta inflación y la devaluación de la moneda; el escenario resulta bastante complicado para el consumidor y las empresas proveedoras de bienes y servicios. En este sentido, las PyMES turísticas de Mochima, ubicadas en el Estado Sucre, Venezuela, se presentan como una alternativa para de alguna manera ayudar a disipar ese triste escenario, mediante sus bondades y en combinación con Internet. De allí que el presente artículo aborde desde los aspectos teóricos del turismo hasta las bondades naturales y culturales que ofrece esta zona oriental del país. Se utilizó una metodología de carácter descriptiva y una combinación de estrategia documental y de campo. Se aplicó un muestreo no probabilístico de tipo intencional, seleccionando los elementos con base en criterios de los investigadores. De acuerdo al estudio, se diseñó la página web y se concluyó, que la implementación de la misma ayudaría en gran medida a mejorar los ingresos de la región y darse a conocer tanto a nivel nacional como internacional.

  14. The common coot as sentinel species for the presence of West Nile and Usutu flaviviruses in Central Europe

    Czech Academy of Sciences Publication Activity Database

    Straková, Petra; Šikutová, Silvie; Jedličková, Petra; Sitko, J.; Rudolf, Ivo; Hubálek, Zdeněk

    2015-01-01

    Roč. 102, October (2015), s. 159-161 ISSN 0034-5288 EU Projects: European Commission(XE) 261504 Institutional support: RVO:68081766 Keywords : West Nile virus * Usutu virus * Common coot * Fulica atra * Surveillance * Mosquito -borne viruses * Culex spp. Subject RIV: EG - Zoology Impact factor: 1.504, year: 2015

  15. First Report of Cowpea Mild Mottle Carlavirus on Yardlong Bean (Vigna unguiculata subsp. sesquipedalis in Venezuela

    Directory of Open Access Journals (Sweden)

    Edgloris Marys

    2012-12-01

    Full Text Available Yardlong bean (Vigna unguiculata subsp. sesquipedalis plants with virus-like systemic mottling and leaf distortion were observed in both experimental and commercial fields in Aragua State, Venezuela. Symptomatic leaves were shown to contain carlavirus-like particles. RT-PCR analysis with carlavirus-specific primers was positive in all tested samples. Nucleotide sequences of the obtained amplicons showed 84%–74% similarity to corresponding sequences of Cowpea mild mottle virus (CPMMV isolates deposited in the GenBank database. This is the first report of CPMMV in Venezuela and is thought to be the first report of CPMMV infecting yardlong bean.

  16. Venezuela paneb kokku regionaalset energeetikaliitu / Allan Espenberg

    Index Scriptorium Estoniae

    Espenberg, Allan

    2007-01-01

    Venezuela pealinnas toimus organisatsiooni Petrocaribe kolmas tippkohtumine. Petrocaribe, mis liidab peamiselt Kariibi mere riike ja tegeleb energeetikaküsimustega, algatas 2 aastat tagasi Venezuela president Hugo Chavez. Organisatsiooni kuulub 16 riiki

  17. Venezuela Rahvusraamatukogu juht kuulutas sõja

    Index Scriptorium Estoniae

    2008-01-01

    Venezuela Rahvusraamatukogu direktor Fernando Baez kuulutas, et tema juhtimisel püüab Venezuela rahvusraamatukogu saavutada juhirolli Ladina-Ameerikas, kuna USA Kongressi Raamatukogust on saanud raamatukogude suurimaid vaenlasi ajaloos

  18. Venezuela: A Full-Year Study

    National Research Council Canada - National Science Library

    Higdon, Melody

    2006-01-01

    This Country Climatology Digest is a climatological study of Venezuela. After describing the geography and major meteorological features of the entire region, the study discusses in detail the climatic controls of Venezuela's weather...

  19. Kaos. Venezuelas top flirter med Hizbollah

    DEFF Research Database (Denmark)

    Gelardi, Maiken

    2017-01-01

    Terrororganisationen Hizbollah har længe brugt Venezuela som base i det ekstremt lukrative narkotikamarked.......Terrororganisationen Hizbollah har længe brugt Venezuela som base i det ekstremt lukrative narkotikamarked....

  20. Venezuela nationalises oil and gas industries

    International Nuclear Information System (INIS)

    Wertheim, Peter Howard; Abrantes, Dayse

    2007-01-01

    Venezuela President Hugo Chavez has stated he will nationalise the Orinoco belt's extra-heavy oil operations and ask for 'special powers' to rule the country. Since last year, the government has been negotiating with international consortia currently operating in the Orinoco area, so that Venezuela state-owned Petroleos de Venezuela SA (PDVSA) attains a majority stake in each project (ml)

  1. Venezuela natural gas outlook

    International Nuclear Information System (INIS)

    Silva, P.

    1991-01-01

    This paper reports on the natural gas outlook for Venezuela. First of all, it is very important to remember that in the last few years we have had frequent and unforeseen changes in the energy, ecological, geopolitical and economical fields which explain why all the projections of demand and prices for hydrocarbons and their products have failed to predict what later would happen in the market. Natural gas, with its recognized advantages over other traditional competitors such as oil, coal and nuclear energy, is identified as the component that is acquiring more weight in the energy equation, with a strengthening projection, not only as a resource that covers demand but as a key element in the international energy business. In fact, natural gas satisfies 21% of overall worldwide energy consumption, with an annual increase of 2.7% over the last few years, which is higher than the global energy growth of other fossil fuels. This tendency, which dates from the beginning of the 1980's, will continue with a possibility of increasing over the coming years. Under a foreseeable scenario, it is estimated that worldwide use of natural gas will increase 40% over the next 10 years and 75% on a longer term. Specifically for liquid methane (LNG), use should increase 60% during this last decade. The LPG increase should be moderate due to the limited demand until 1995 and to the stable trends that will continue its use until the end of this century

  2. Serologic survey of birds for West Nile Flavivirus in Southern Moravia (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk; Halouzka, Jiří; Juřicová, Zina; Šikutová, Silvie; Rudolf, Ivo; Honza, Marcel; Janková, J.; Chytil, J.; Marec, František; Sitko, J.

    2008-01-01

    Roč. 8, č. 3 (2008), s. 659-666 ISSN 1530-3667 R&D Projects: GA AV ČR IAA600930611 EU Projects: European Commission(XE) 10284 - EDEN Institutional research plan: CEZ:AV0Z60930519; CEZ:AV0Z50070508 Source of funding: R - rámcový projekt EK Keywords : virus West Nile * virus Usutu * Flaviviridae * mosquito -borne viruses * birds Subject RIV: EE - Microbiology, Virology Impact factor: 2.195, year: 2008

  3. 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.

  4. Oil Prices and Venezuela's Economy

    OpenAIRE

    Mark Weisbrot; Rebecca Ray

    2008-01-01

    This paper looks at Venezuela’s export revenue, imports, and trade and current account balances under a range of oil price outcomes for the next two years. It finds that Venezuela would run large current account surpluses for prices between $60-90 per barrel, and would even run a small surplus with prices at $50 per barrel. (Most oil industry estimates for the next two years are in the range of $80-90 per barrel). The authors conclude that Venezuela is unlikely to run into foreign exchange co...

  5. Lasers and petroleum in Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    da Costa, G.; Guerri, G.; Calatroni, J. (Universidad Simon Bolivar, Caracas (Venezuela). Lab. de Optica Cuantica)

    1978-06-01

    The viscosity of heavy hydrocarbons is one reason why conventional drilling methods are insufficient for petroleum extraction in Venezuela at a depth of 1000 m. The Quantum Optics Laboratory of Simon Bolivar University in Caracas is conducting a search for novel perforation and heating tools for petroleum extraction. Basic research is being carried out using a 10 MW TEA-CO/sub 2/ laser. The laser is not only a research tool but a matter of national interests, as petroleum is Venezuela's main export article.

  6. Global emergence of Zika virus

    Directory of Open Access Journals (Sweden)

    Richard Tjan

    2016-05-01

    Full Text Available Zika virus (ZIKV belongs to the flaviviruses (family Flaviviridae, which includes dengue, yellow fever, West Nile, and Japanese encephalitis viruses. Zika virus was isolated in 1947, in the Zika forest near Kampala, Uganda, from one of the rhesus monkeys used as sentinel animals in a yellow fever research program.

  7. Pro-inflammatory cytokines derived from West Nile virus (WNV-infected SK-N-SH cells mediate neuroinflammatory markers and neuronal death

    Directory of Open Access Journals (Sweden)

    Nerurkar Vivek R

    2010-10-01

    Full Text Available Abstract Background WNV-associated encephalitis (WNVE is characterized by increased production of pro-inflammatory mediators, glial cells activation and eventual loss of neurons. WNV infection of neurons is rapidly progressive and destructive whereas infection of non-neuronal brain cells is limited. However, the role of neurons and pathological consequences of pro-inflammatory cytokines released as a result of WNV infection is unclear. Therefore, the objective of this study was to examine the role of key cytokines secreted by WNV-infected neurons in mediating neuroinflammatory markers and neuronal death. Methods A transformed human neuroblastoma cell line, SK-N-SH, was infected with WNV at multiplicity of infection (MOI-1 and -5, and WNV replication kinetics and expression profile of key pro-inflammatory cytokines were analyzed by plaque assay, qRT-PCR, and ELISA. Cell death was measured in SK-N-SH cell line in the presence and absence of neutralizing antibodies against key pro-inflammatory cytokines using cell viability assay, TUNEL and flow cytometry. Further, naïve primary astrocytes were treated with UV-inactivated supernatant from mock- and WNV-infected SK-N-SH cell line and the activation of astrocytes was measured using flow cytometry and ELISA. Results WNV-infected SK-N-SH cells induced the expression of IL-1β, -6, -8, and TNF-α in a dose- and time-dependent manner, which coincided with increase in virus-induced cell death. Treatment of cells with anti-IL-1β or -TNF-α resulted in significant reduction of the neurotoxic effects of WNV. Furthermore treatment of naïve astrocytes with UV-inactivated supernatant from WNV-infected SK-N-SH cell line increased expression of glial fibrillary acidic protein and key inflammatory cytokines. Conclusion Our results for the first time suggest that neurons are one of the potential sources of pro-inflammatory cytokines in WNV-infected brain and these neuron-derived cytokines contribute to WNV

  8. Health Physics Education in Venezuela

    International Nuclear Information System (INIS)

    Solanas, J.

    1979-01-01

    Training courses on health physics have been organized regularly in Venezuela since 1962. The basic course consists of 20 hours for theoretical tuition and 10 hours for laboratory practice. Post-graduate courses have been organized by the Central University since 1965. Radiological technicians receive their training through the courses organized by the Ministry of Health. (author)

  9. World status: Petroleos de Venezuela

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    A brief review is given of the petroleum industry in Venezuela. The industry was nationalized in 1975 and by 1990 was the world's fifth largest oil company. They have ambitious plans to expand production capacity and are looking to the major oil companies to assist. The prospects for sales of Orimulsion are also discussed. (UK)

  10. Energy sector developments in Venezuela

    International Nuclear Information System (INIS)

    Pantin, R.

    1997-01-01

    The current state and future development of the oil, gas and coal sector in Venezuela was discussed. Venezuela has oil reserves of 73 billion barrels, gas reserves of 143 TCF and coal reserves of 6 billion BOE. The country has a refining capacity of 2.9 million barrels per day, a petrochemical capacity of 7.7 million tons per year, and a coal capacity of 4.6 million tons per year. The largest refiners in Venezuela are Shell, Exxon, PDVSA, Mobil, BP, Chevron and Texaco. In 1996 the total oil and derivatives exports for Venezuela were 2.8 million barrels per day. Fifty-eight companies from 14 countries participate in the Venezuelan upstream market. Fifteen operating agreements have been awarded to 27 companies from nine countries. Third round operating agreements have been awarded to 26 companies and profit sharing agreements are in force involving 14 companies. Four vertically integrated projects (Maraven-Conoco, Maraven-Total, Corpoven-Arco-Texaco-Phillips, and Lagoven-Mobil-Veba) are currently underway. The Orimulsion(R) project, the refining system, the natural gas production, marketing and transmission system, associated future projects for the 1997-2006 time frame, and developments in the field of petrochemicals also have been reviewed. 21 figs

  11. English Teaching Profile (Provisional): Venezuela.

    Science.gov (United States)

    British Council, London (England). English Language and Literature Div.

    This profile of the English language teaching situation in Venezuela discusses the status of English in society and in the educational system. It also gives an account of Venezuelan political, economic, and social life. A description is given of the education system and reforms that have been proposed for nursery school through higher education.…

  12. International Commercial Arbitration in Venezuela

    Directory of Open Access Journals (Sweden)

    Elena P. Ermakova

    2014-03-01

    Full Text Available In the above article author describes evolution of legal regulation of international commercial arbitration in Venezuela. Author cites statistics of arbitration centers in Venezuela activities. In past two decades many Latin American countries have reformed their arbitration law. In an effort to modernize its arbitral institutions several Latin American countries adopted Model Law on International Commercial Arbitration of the UN Commission on International Trade Law (UNCITRAL. In addition, many Latin American countries have adopted the monistic system. Author pays detailed attention to this issue, discusses concept of a monistic system - a system in which a unique set of rules governs both domestic and international arbitration. Author argues that legal system of Venezuela fits this definition. Venezuelan law on arbitration in 1998 makes no distinction between domestic and international arbitration. Arbitration was included in judicial system under the Constitution of Venezuela of the 1999. Art. 258 of the Venezuelan Constitution states that arbitration, conciliation and mediation are alternative ways of resolving disputes.

  13. West Nile Virus: Prevention and Control

    Science.gov (United States)

    ... not likely to be effective. Take steps to control mosquitoes inside and outside your home Use screens ... August 14, 2017 Content source: Centers for Disease Control and Prevention National Center for Emerging and Zoonotic ...

  14. Nanoscience and nanotechnology in Venezuela

    Science.gov (United States)

    López Cadenas, María Sonsiré; Hasmy, Anwar; Vessuri, Hebe

    2011-08-01

    Nanoscale research in Venezuela is briefly reviewed, with emphasis on research groups, research lines, and institutions involved. A summary exploration is made of international collaboration through scientific co-authorship, as well of the efforts to build nano capacities, available infrastructure, relationships to the productive sector and a weak presence in Venezuelan public policies, although there is some expectation that the situation may soon begin to change.

  15. The White Nile sedimentary system

    Science.gov (United States)

    Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Resentini, Alberto; Vezzoli, Giovanni; Villa, Igor

    2014-05-01

    The Nile River flows for ~6700 km from south of the Equator to finally reach the Mediterranean Sea at northern subtropical latitudes (Woodward et al. 2007). This is the longest sedimentological laboratory on Earth, a unique setting in which we are investigating changes in sediment composition associated with diverse chemical and physical processes, including weathering and hydraulic sorting. The present study focuses on the southern branch of the Nile across 20° of latitude, from hyperhumid Burundi and Rwanda highlands in central Africa to Khartoum, the capital city of Sudan at the southern edge of the Sahara. Our study of the Kagera basin emphasizes the importance of weathering in soils at the source rather than during stepwise transport, and shows that the transformation of parent rocks into quartzose sand may be completed in one sedimentary cycle (Garzanti et al. 2013a). Micas and heavy minerals, less effectively diluted by recycling than main framework components, offer the best key to identify the original source-rock imprint. The different behaviour of chemical indices such as the CIA (a truer indicator of weathering) and the WIP (markedly affected by quartz dilution) helps us to distinguish strongly weathered first-cycle versus polycyclic quartz sands (Garzanti et al. 2013b). Because sediment is efficiently trapped in East African Rift lakes, the composition of Nile sediments changes repeatedly northwards across Uganda. Downstream of both Lake Kyoga and Lake Albert, quartzose sands are progressively enriched in metamorphiclastic detritus supplied from tributaries draining amphibolite-facies basements. The evolution of White Nile sediments across South Sudan, a scarcely accessible region that suffered decades of civil war, was inferred from the available information (Shukri 1950), integrated by original petrographic, heavy-mineral and geochemical data (Padoan et al. 2011). Mineralogical and isotopic signatures of Bahr-el-Jebel and Sobat sediments, derived

  16. Sentinel Surveillance of Influenza-Like Illness in Two Hospitals in Maracay, Venezuela: 2006–2010

    Science.gov (United States)

    Comach, Guillermo; Teneza-Mora, Nimfa; Kochel, Tadeusz J.; Espino, Carlos; Sierra, Gloria; Camacho, Daria E.; Laguna-Torres, V. Alberto; Garcia, Josefina; Chauca, Gloria; Gamero, Maria E.; Sovero, Merly; Bordones, Slave; Villalobos, Iris; Melchor, Angel; Halsey, Eric S.

    2012-01-01

    Background Limited information exists on the epidemiology of acute febrile respiratory illnesses in tropical South American countries such as Venezuela. The objective of the present study was to examine the epidemiology of influenza-like illness (ILI) in two hospitals in Maracay, Venezuela. Methodology/Principal Findings We performed a prospective surveillance study of persons with ILI who presented for care at two hospitals in Maracay, Venezuela, from October 2006 to December 2010. A respiratory specimen and clinical information were obtained from each participant. Viral isolation and identification with immunofluorescent antibodies and molecular methods were employed to detect respiratory viruses such as adenovirus, influenza A and B, parainfluenza, and respiratory sincytial virus, among others. There were 916 participants in the study (median age: 17 years; range: 1 month – 86 years). Viruses were identified in 143 (15.6%) subjects, and one participant was found to have a co-infection with more than one virus. Influenza viruses, including pandemic H1N1 2009, were the most frequently detected pathogens, accounting for 67.4% (97/144) of the viruses detected. Adenovirus (15/144), parainfluenza virus (13/144), and respiratory syncytial virus (11/144) were also important causes of ILI in this study. Pandemic H1N1 2009 virus became the most commonly isolated influenza virus during its initial appearance in 2009. Two waves of the pandemic were observed: the first which peaked in August 2009 and the second - higher than the preceding - that peaked in October 2009. In 2010, influenza A/H3N2 re-emerged as the most predominant respiratory virus detected. Conclusions/Significance Influenza viruses were the most commonly detected viral organisms among patients with acute febrile respiratory illnesses presenting at two hospitals in Maracay, Venezuela. Pandemic H1N1 2009 influenza virus did not completely replace other circulating influenza viruses during its initial

  17. Epidemiology of sporotrichosis in Venezuela.

    Science.gov (United States)

    Mata-Essayag, Sofia; Delgado, Alejandro; Colella, Maria T; Landaeta-Nezer, Maria E; Rosello, Arantza; Perez de Salazar, Celina; Olaizola, Carolina; Hartung, Claudia; Magaldi, Sylvia; Velasquez, Etna

    2013-08-01

    Sporotrichosis is one of the most common subcutaneous mycoses in Venezuela. It is a granulomatous chronic infection with cutaneous or subcutaneous tissue lesions. Regional lymphatic involvement may be present; extracutaneous disease is rare. The causal fungus Sporothrix schenckii has been isolated from soil, vegetation, and animals on numerous occasions and in many localities throughout the world. The aim of this study is to describe clinical and epidemiological features of cases of sporotrichosis observed in Venezuela and review of the literature. We included the demographic data, clinical features, diagnostic methods, treatment, and follow-up of patients with sporotrichosis from 1963 to 2009, diagnosed at the Department of Medical Mycology. One-hundred and thirty-three sporotrichosis cases were diagnosed. Most patients were under the age of 30 years (66.15%). In 61.6% of them, the mode of transmission was not identified. The predominant clinical form in this population was lymphocutaneous (63.15%). Direct microscopic diagnosis was performed in 123 cases, and 57.9% yielded positive results for asteroid body. Sporotrichosis is an endemic subcutaneous mycosis in Venezuela. There are no reports to this date of disseminated forms of the disease, even amongst patients with acquired immunodeficiency syndrome. Direct microscopic examination of wet mount slides with saline solution or distilled water in the search for asteroid bodies is paramount. Saturated sodium and potassium iodine solutions continue to be extremely efficacious and affordable to most of our patients, therefore our treatment of choice. © 2013 The International Society of Dermatology.

  18. Venezuela opens up to explorers

    International Nuclear Information System (INIS)

    Kielmas, M.

    1995-01-01

    The opening of Venezuela's first exploration bidding round since oil nationalisation in 1976 was a turning-point in the country's energy policy. The state oil company, Petroleos de Venezuela (PdVSA), has said that the bidding round could generate investment of some $11 billion eventually in development investment and that over the next 10 years, nearly 20 percent of a planned $55 billion, 10-year state oil company investment programme could also come from foreign or private sector oil investment. Should this optimistic prediction materialise, Venezuela, whose 2.75 million b/d oil production in October was some 400,000 b/d over its Opec quota, will remain both the dominant oil producer in Latin America and the top-ranking oil exporter to the US market. In May this year, Venezuelan oil exports topped 1.43 million b/d, or some 16.8 percent of the US market, compared with Saudi Arabia's 15.7 percent. (author)

  19. Susceptibility status of Aedes aegypti (L.) (Diptera: Culicidae) to temephos in Venezuela.

    Science.gov (United States)

    Alvarez, Leslie C; Ponce, Gustavo; Oviedo, Milagros; Lopez, Beatriz; Flores, Adriana E

    2014-08-01

    Temephos is an insecticide widely used in Venezuela to control the proliferation of the larvae of Aedes aegypti (L.), the principal vector of dengue virus. The aim of this study was to identify the susceptibility to temephos of Ae. aegypti in four locations in western Venezuela: Lara, Tres Esquinas, Ureña and Pampanito. Larval bioassays were conducted on samples collected in 2008 and 2010, and the levels of α- and β-esterases, mixed-function oxidases, glutathione-S-transferase and insensitive acethyl cholinesterase were determined. Larval populations from western Venezuela obtained during 2008 and 2010 were found to be susceptible to temephos, with low resistance ratios and without overexpression of enzymes. The low RR values reveal the effectiveness of temephos in controlling the larval populations of Ae. aegypti. Control strategies must be vigorously monitored to maintain the susceptibility to temephos of these populations of Ae. aegypti. © 2013 Society of Chemical Industry.

  20. Venezuela: Background and U.S. Relations

    Science.gov (United States)

    2016-11-21

    supported the 30 Amnesty International, “Venezuela, Los Derechos Humanos en Riesgo en Medio de Protestas...iachr/docs/annual/2015/doc-en/ InformeAnual2015-cap4-Venezuela-EN.pdf Programa Venezolano de Educación-Acción en Derechos Humanos (PROVEA) http

  1. Lepra en Venezuela 1978 - 1997

    OpenAIRE

    Merkl A., Federico

    2002-01-01

    El programa de lepra en Venezuela describe a 8 859 pacientes diagnosticados y tratados entre 1978 y 1997. Debido a características propias de la patología se presume que no todos los enfermos son captados y se aplica una metodología para estimar la "prevalencia real" de la enfermedad. Encontramos que su distribución es desigual en el país y que a pesar de haberse alcanzado el criterio de eliminación a nivel nacional, el problema persiste en un grupo de sus estados. The program of leprosy i...

  2. Hyperreactive malarial splenomegaly in Venezuela.

    Science.gov (United States)

    Torres, J; Noya, O; Mondolfi, A; Peceño, C; Botto, C

    1988-07-01

    A cross-sectional seroepidemiological survey seeking hyperreactive malarial splenomegaly was carried out in isolated Yanomami hamlets in Amazonas Territory in Venezuela. All 110 inhabitants greater than 1 year of age were evaluated clinically and 98 were studied immunologically. The spleen index for individuals greater than 10 years of age was 44%. Only 3 patients had Plasmodium spp. on thick blood smears. All had serological evidence of infection with Plasmodium falciparum and P. vivax. Twenty-three patients were considered to show hyperreactive malarial splenomegaly. Clinical manifestations of the syndrome did not differ from those described in other parts of the world.

  3. Rapid Identification of Dengue Virus Serotypes Using Monoclonal Antibodies in an Indirect Immunofluorescence Test.

    Science.gov (United States)

    1982-06-18

    encephalitis(TBH-28), West Nile(E-101), Yellow fever(French neurotropic and 17D strains), and Zika . Two Sandfly Fever viruses (213452 and Candiru) were...were provided as first passage isolates ( Aedes pseudoscutellaris cells, AP-61) or human serum from recent dengue virus patients. African isolates... viruses of the Phlebovirus genus (Table 1). Several monoclonal antibody preparations reacted solely with dengue virus serotypes. Two preparations (13E7 and

  4. Importance of energy efficiency in Venezuela

    International Nuclear Information System (INIS)

    Corrie, R.

    1991-01-01

    Venezuela's economic development relies heavily on oil. The nation's energy production equals 3.5 million barrels of oil equivalent (boe) per day. Oil comprises 71% of the energy Venezuela produces, natural gas 20%, hydro 9% and coal 1%. Of the energy produced, Venezuela exports three quarters and consumes the remainder. Over 99% of Venezuela's energy exports are crude oil and oil products. Economic problems have constrained Venezuela's development in recent years. Saddled with an external debt of $US 32 billion, Venezuela will continue to encounter barriers for years to come. The nation is, however, in the process of restructuring its economy. As part of this process, the Venezuelan government has begun to integrate opportunities for improving the efficiency of its energy use. As a major oil producer and exporter, Venezuela is conscious of its responsibility to the international community to limit its emissions of energy-related CO 2 into the atmosphere. For this reason, the Venezuelan government is in the process of creating a program to conserve and ration the use of energy. This effort incorporates a number of measures including the substitution of natural gas for liquid fuels for all end uses (including transportation activities), the increased reliance on hydropower in the generation of electricity and the reduction of waste in the production of natural gas to 2% of the economically recollectable volume

  5. Quality of democracy in Venezuela

    Directory of Open Access Journals (Sweden)

    Daniel H. LEVINE

    2013-01-01

    Full Text Available Discussions of democracy in contemporary Venezuela lack a settled definition of the subject, how to study it, or indeed of what counts as «democracy» in the first place. The regime has been described as everything from participatory democracy, hybrid, mixed, and personalist to populist, illiberal, or no longer democratic but rather competitive authoritarian. The goal of this article is to measure the quality of democracy in Venezuela, within the terms of a procedural concept of democracy as detailed in our earlier work. Empirical measurement of the quality of democracy on five dimensions (electoral choice, participation, responsiveness, accountability, sovereignty reveals a low level overall and deep institutional weakness under a personalist leadership, with little change from 2005 to 2010. Future scenarios, after the 2012 presidential election result, include reinforcement of authoritarian trends, open militarization, liberalization and institutional strengthening, or long term volatility and polarized conflict. All scenarios are contingent on the health of President Chávez, who is a central unifying factor for his movement and regime

  6. Pediatric multiple sclerosis in Venezuela

    Directory of Open Access Journals (Sweden)

    Joaquín A. Peña

    2012-04-01

    Full Text Available OBJECTIVE: To describe the epidemiological and clinical characteristics of Venezuelan pediatric patients with multiple sclerosis (MS. METHODS: Database records from the National Program for MS were searched for patients with an established diagnosis of MS whose first symptoms appeared before age 18. RESULTS: The national database held records of 1.710 patients; 3.8% had onset of the first symptoms before age 18. 46.7% were boys, yielding an F:M ratio of 1.13:1. Many children had a disease onset characterized by motor impairment (30.7%, brainstem/cerebellum and spinal cord affectation (27.6%, headache (26%. Less frequent symptoms were sensory symptoms (8% and optic neuritis (7%. DISCUSSION: Pediatric MS patients in Venezuela represent a significant proportion of all MS cases. The clinical pattern is characterized by motor symptoms at onset, and predominantly monosymptomatic presentation with a relapsing-remitting pattern. This is the first systematic attempt to estimate the prevalence of pediatric MS in Venezuela.

  7. Venezuela: World Oil Report 1991

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This paper reports on Venezuela's expansion by state oil company PDVSA has gone from a mere concept a year ago to a well-defined plan. The five-year project that began this year and runs through 1995 received a $4-billion upgrading last fall to $25 billion. Money will be spent in increments of $5 billion/year, and all sectors are involved. Largest share, about $10.5 billion, will go to upstream projects, with $6 billion to be invested in refining, $6 billion in petrochemicals, $1.5 billion in coal and $800 million in domestic marketing. PDVSA intends to finance most of the spending directly from its cash flow. The upstream spending will go toward boosting oil production to more than 3.6 MMbpd by the beginning of 1996, with capacity topping at 4.2 MMbopd. Such heavy spending should prove a boon to the Venezuelan economy. The oil industry constitutes 23% of Venezuela's GNP, accounts for 75% of governmental revenues and produces 70% of the nation's annual foreign exchange earnings. The Ministry of Planning already is forecasting a 7% leap in real growth of the GNP this year

  8. Republic of Venezuela. Country profile.

    Science.gov (United States)

    Hakkert, R

    1985-06-01

    Venezuela's current economic and demographic situation is described. Venezuela is a major oil country, and the oil industry accounts for 90% of the country's foreign exchange, 70% of the government's revenues, and 15% of the gross domestic product. The economy experienced a sudden and high rate of economic growth in the mid-1970s as a result of high oil prices; however, in recent years, declining oil prices have had a negative effect on the economy. The country is now faced with a serious trade deficit, and the government recently imposed restrictions on imports. Imports in recently years had increased markedly. The emphasis on the oil industry weakened the agricultural sector and, as a result, food imports increased. In addition, the rapid economic growth experienced during the 1970s greatly increased the demand for imported consumer goods. Venezuela has the 4th highest foreign debt in the world (US$35 billion). Despite these problems Venezuela has a relatively high per capita income (US$4,140) and living standard, compared to other countries in the region. Venezuela's total population is 14.6 million, and the population is unevenly distributed. 86% of the population lives in cities of 2500 or more. 37.4% of the population and 70% of the industry is concentrated in the Federal District which contains Caracas, and in the surrounding states of Aragua, Miranda, and Carabobo. This area constitutes only 2.36% of the country's territory. Most of the oil fields are located in the state of Zulia which also contains the country's 2nd largest city (Maracaibo). The country's coastal area contains most of the agricultural lands, and the prairies just south of the coastal mountain ranges are devoted primarily to cattle raising. The remaining 58.2% of the country's territory is essentially jungle and contains only 6.9% of the country's population. The annual population growth rate is 3.11%. Although the rate declined in recent years it is higher than in most of the other

  9. Peste des petits ruminants outbreaks in White Nile State, Sudan

    Directory of Open Access Journals (Sweden)

    Osama M. Ishag

    2015-08-01

    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.

  10. Heavy water. A production alternative for Venezuela

    International Nuclear Information System (INIS)

    A survey of heavy water production methods is made. Main facts about isotopic and distillation methods, reforming and coupling to a Hydrogen distillation plant are presented. A feasibility study on heavy water production in Venezuela is suggested

  11. Molecular epidemiology suggests Venezuela as the origin of the dengue outbreak in Madeira, Portugal in 2012-2013.

    Science.gov (United States)

    Franco, L; Pagan, I; Serre Del Cor, N; Schunk, M; Neumayr, A; Molero, F; Potente, A; Hatz, C; Wilder-Smith, A; Sánchez-Seco, M P; Tenorio, A

    2015-07-01

    An explosive epidemic occurred in Madeira Island (Portugal) from October 2012 to February 2013. Published data showed that dengue virus type 1 introduced from South America was the incriminated virus. We aim to determine the origin of the strain introduced to Madeira by travellers returning to Europe. Using phylogeographic analysis and complete envelope sequences we have demonstrated that the most probable origin of the strain is Venezuela. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Virus Information Update CIAC-2301

    Science.gov (United States)

    1998-05-21

    a tune through a sound card. Byway is reported to be in the wild internationally, especially in Venezuela, Mexico , Bulgaria, UK and USA. REMOVAL NOTE...1482, Varicella Type: Program. Disk Location: Features: Damage: Size: See Also: Notes: v6-146: This virus was written to hurt users of the TBCLEAN...antivirus package. If you have a file infected with the Varicella virus, and if you tried to clean this virus infected file with tbclean, what would

  13. TSUNAMI HAZARD IN NORTHERN VENEZUELA

    Directory of Open Access Journals (Sweden)

    B. Theilen-Willige

    2006-01-01

    Full Text Available Based on LANDSAT ETM and Digital Elevation Model (DEM data derived by the Shuttle Radar Topography Mission (SRTM, 2000 of the coastal areas of Northern Venezuela were investigated in order to detect traces of earlier tsunami events. Digital image processing methods used to enhance LANDSAT ETM imageries and to produce morphometric maps (such as hillshade, slope, minimum and maximum curvature maps based on the SRTM DEM data contribute to the detection of morphologic traces that might be related to catastrophic tsunami events. These maps combined with various geodata such as seismotectonic data in a GIS environment allow the delineation of coastal regions with potential tsunami risk. The LANDSAT ETM imageries merged with digitally processed and enhanced SRTM data clearly indicate areas that might be prone by flooding in case of catastrophic tsunami events.

  14. [Experiences of the urbanization process in Venezuela].

    Science.gov (United States)

    Martinez Tirado, N

    1985-01-01

    The process of urbanization and urban growth in relation to economic development in Venezuela is analyzed. Four periods are considered: the period prior to the discovery of oil in Venezuela, which ended in the early 1940s; from the 1940s to the early 1970s; from the 1970s to 1983; and the present. Information is provided for the period 1936-1981 on total and urban population growth and on the size and number of urban centers.

  15. Nuclear power planning study for Venezuela

    International Nuclear Information System (INIS)

    1978-01-01

    The optimum capacity for nuclear power plants that might be built in Venezuela in the period 1985-2000 and the best time for incorporating them into the electric system is defined. The most recent forecasts regarding growth of the population and demand, and of the economy in general, and the taking into account the costs for the fossil-fuel and hydroelectric resources known to exist in Venezuela, as compared with the costs of importing uranium, are discussed

  16. Radioactive wastes handling problems in Venezuela

    International Nuclear Information System (INIS)

    Ramirez, R.; Venegas, R.

    1984-07-01

    A brief description of the radioactive wastes problem in Venezuela is presented. The origins of the problem are shown in a squematic form. The requirements for its solution are divided into three parts: information system, control system, radioactive wastes hadling system. A questionnaire summarizing factors to be considered when looking for a solution to the problem in Venezuela is included, as well as conclusions and recomendations for further discussion

  17. Calidad de la democracia en Venezuela

    Directory of Open Access Journals (Sweden)

    Luis Eduardo León Ganatios

    2014-01-01

    Full Text Available A partir de una reforma constitucional en Venezuela, en el año 1999 se introdujeron mecanismos de democracia directa como el referendo o el plebiscito. A pesar de que este proceso amplió las vías de participación ciudadana en la vida política, hubo importantes retrocesos en libertades y derechos civiles y políticos básicos. La finalidad de este artículo consiste en medir la calidad de la democracia en Venezuela con base en una serie de indicadores derivados de la concepción de poliarquía de Robert Dahl (1993.Palabras Clave: Calidad de la democracia; Venezuela; Indicadores; estudio comparado; poliarquía.Quality of Democracy in VenezuelaAbstractSince 1999 a constitutional reform in Venezuela introduced some mechanisms of direct democracy such as the referendum and the plebiscite. Although this process broadened the means for citizens’ participation in the political system, there were important setbacks in political and civil liberties. The goal of this paper is to measure the quality of democracy according to a series of indicators that draw upon Robert Dahl’s conception of polyarchy.Keywords: Quality of democracy; Venezuela; indicators; comparative studies; polyarchy.

  18. Ecology of West Nile Fever across four European countries: Review of weather profiles, vector population dynamics and vector control response

    Science.gov (United States)

    West Nile virus (WNV) represents a serious burden to human and animal health because of its capacity to cause large unforeseen epidemics. Until 2004, only lineage 1 and 3 WNV strains had been found in Europe. Lineage 2 strains were initially isolated in 2004 (Hungary), again in 2008 (Austria), and f...

  19. Control Over the Nile: Implications across Nations

    Science.gov (United States)

    2010-06-01

    states is evident in the 1959 Full Utilization of the Nile Waters Agreement between Egypt and the Sudan. Of the Nile’s annual average water yield of...grain, maize —has been falling. Kenya saw a 22 per cent decrease in 2000 from the 1998 harvest and a 36 per cent decrease from the 1999 harvest—leading...incorporated in a Nile water resource-sharing regime. The potential for Nile basin conflict or cooperation revolves around, first, the gap between water

  20. Serologic survey of humans for Flavivirus West Nile in southern Moravia (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk; Kříž, B.; Halouzka, Jiří

    2011-01-01

    Roč. 19, č. 3 (2011), s. 131-133 ISSN 1210-7778 R&D Projects: GA AV ČR IAA600930611 EU Projects: European Commission(XE) 10284 - EDEN Institutional research plan: CEZ:AV0Z60930519 Keywords : West Nile virus * Flavivirus * Moravia * serosurvey Subject RIV: FN - Epidemiology, Contagious Diseases ; Clinical Immunology http://www.szu.cz/svi/cejph/show_en.php?kat=archiv/2011-3-03

  1. Muuga joodab Venezuela naftaga Valgevene tehaseid / Anne Oja

    Index Scriptorium Estoniae

    Oja, Anne, 1970-

    2010-01-01

    Venezuela toornaftat veetakse Valgevenesse Muuga sadama kaudu. Riia sadam loodab suurema osa Venezuela nafta transiidist endale saada, samas peaks sadam selleks tegema mitmeid töid, nt. süvendama akvatooriumi

  2. Venezuela: Political Conditions and U.S. Policy

    National Research Council Canada - National Science Library

    Sullivan, Mark P

    2005-01-01

    ... who was first elected in 1998. Under Ch vez, Venezuela has undergone enormous political changes, with a new constitution in place, a new unicameral legislature, and even a new name for the country, the Bolivarian Republic of Venezuela...

  3. Can Venezuela's oil sector endure Chavez' ambitions any longer?

    International Nuclear Information System (INIS)

    Honkoop, J.

    2009-07-01

    The author describes the decline of Venezuela's oil industry as well as President Chavez' reaction to Venezuela's budgetary crisis. Politicization, falling investment and the obligation to take upon itself a plethora of social spending have left national oil company Petroleos de Venezuela, S.A. unable to produce efficiently and maintain production levels. Falling oil production and lower oil prices have in turn left president Hugo Chavez unable to spread the wealth to Venezuela's poor and he is searching desperately for ways to extract yet more from Venezuela's dysfunctional economy. As funds run out, Venezuela's expensive foreign policy, supporting regional allies, in particular Cuba, and seeking to export anywhere but the United States, proves overly expensive. Venezuela's impoverished masses, still supportive of Chavez during February's elections, may become less so as funds for social programmes run out. For Chavez it is a time for making choices... otherwise the people of Venezuela will choose for him. [nl

  4. Espacios culturales comunitarios en Venezuela

    Directory of Open Access Journals (Sweden)

    Peña, José Adolfo

    2004-06-01

    Full Text Available The community centre programme in Venezuela (ECC,Spanish initials for Espacios Culturales Comunitarios wasundertaken in 2001 on the initiative of the Deputy Ministry ofCulture’s Department of Cultural Buildings. The idea was todesign an extremely simple, flexible and inexpensive system,readily applicable all across the country and suitable for atropical climate. The programme was headed by ProfessorJuan Pedro Posani, who created the architectural design forthese centres. Engineer José Adolfo Peña and architectCarmen Yáñez authored the structural and buildingengineering. The solutions devised to meet constructionrequirements were based on two principles: the choice of alightweight prefabricated building system and the definition ofthe extreme climatic conditions characteristic of the tropics asthe core issue to be addressed.In terms of architectural and humanist policy, the project is anarchitectural commitment to the environment, buildingtechnology and the conditions and demands of a clearlydisadvantaged social community.El programa de los Espacios Culturales Comunitarios (ECCen Venezuela surge de la dirección de EdificacionesCulturales del ViceMinisterio de Cultura en el año 2001. Laidea consiste en diseñar un sistema extremadamente sencillo,flexible y económico que pueda multiplicarse rápidamentepor todo el país y que sea capaz de responderadecuadamente a las condiciones contextuales del trópico. Elprograma ha sido dirigido por el profesor Juan PedroPosani, quien concibió la arquitectura de los mismos. Laconcepción estructural y constructiva es obra del ingenieroJose Adolfo Peña y de la arquitecta Carmen Yáñez. Larespuesta a las condiciones de partida se basó en dosprincipios: la elección de un sistema de prefabricación ligeray la consideración en primer plano de las condicionesclimáticas extremas propias del trópico.El proyecto, en términos de arquitectura y de política humanista,es un compromiso arquitect

  5. El Fenomeno Chavez: Hugo Chavez of Venezuela, Modern Day Bolivar

    Science.gov (United States)

    2007-03-01

    Venezuela’s state owned oil company, Petroleos de Venezuela. Ever seeking opportunities to provoke the giant United States, Chavez agreed to provide...controlled joint “El Fenomeno Chavez” . . . 9 venture, Petroleos de Venezuela SA (PDVSA). Exxon Mobil Corporation decided to sell their stakes among...exploited. 9. Major oil companies in Venezuela: 1. Petroleos de Venezuela (PdVSA) – government-owned; generates 1/3 of national GDP; monopolized the

  6. 78 FR 55096 - Ferrosilicon from Russia and Venezuela

    Science.gov (United States)

    2013-09-09

    ... from Russia and Venezuela Determination On the basis of the record \\1\\ developed in the subject... Venezuela of ferrosilicon, provided for in subheadings 7202.21.10, 7202.21.50, 7202.21.75, 7202.21.90, and... with material injury by reason of LTFV imports of ferrosilicon from Russia and Venezuela. Accordingly...

  7. 78 FR 58556 - Silicomanganese From India, Kazakhstan, and Venezuela

    Science.gov (United States)

    2013-09-24

    ... From India, Kazakhstan, and Venezuela Determination On the basis of the record \\1\\ developed in the... antidumping duty orders on imports of silicomanganese from India, Kazakhstan, and Venezuela would be likely to... Venezuela. Background The Commission instituted these reviews on October 1, 2012 (77 FR 59970) and...

  8. Democracia y conflicto en Venezuela.

    Directory of Open Access Journals (Sweden)

    Juan Eduardo Romero

    2011-08-01

    Full Text Available El presente trabajo aborda el tema de la democracia en Venezuela desde una perspectiva múltiple y variada. Parte de la consideración de un conjunto de variables (papel del Estado en la sociedad globalizada, la política y el ejercicio del poder, la economía, la política social, los movimientos sociales y las protestas colectivas, medio ambiente y grupos étnicos para realizar una ponderación del curso y los retos de la sociedad democrática venezolana en el período 1988-2008. El trabajo maneja el análisis desde la óptica de la comparación histórica, la historia crítica, la sociología histórica y el pensamiento político para establecer las principales tendencias que ha adquirido la democracia venezolana en cada una de esas variables en el período estudiado, así como la prospectiva que pueden adquirir en los próximos años.

  9. Toxic ornamental plants in Venezuela

    Directory of Open Access Journals (Sweden)

    Carlos Varela Romero

    2017-01-01

    Full Text Available The aim of this research was to contribute information on toxic ornamental plants in Venezuela. Information on taxonomy, common names, habit, origin, status, location, propagation and toxicology (part of the plant, effects was compiled from articles, books, catalogs, herbarium collections. A botanical analysis (taxonomy, common names, habit, origin, status, location, propagation and toxicology (part of the plant, effects was performed. The information about plant poisoning cases was requested to SIMET (Pharmacy faculty -UCV. Seventy-eight species were found in 34 families, the most important were: Apocynaceae (10 genera/12 species, Araceae (9/9, Euphorbiaceae (4/10 and Solanaceae (5/6. Genus Euphorbia was the most species rich. Most species were exotic species (79.5% and shrubs (32.1%. The entire plant (35 and latex (19 were the most toxic parts and the most frequent accidental ingestion (61.5%. Twenty cases were reported between 2009-2013, of which 80% were minors, female and urban areas. There is very little information published in Hispanic American countries

  10. Amino acids profile of four Nile fish

    African Journals Online (AJOL)

    juba

    Environment and Natural Resources Research Institute, the National Centre for ... different species of the Nile fish (Elagba et al., 2010). ... was found to differ between species, sexes, sizes, .... Their ratios were different in body structures of.

  11. NNDSS - Table II. West Nile to Zika

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. West Nile to Zika - 2018. In this Table, provisional cases of selected notifiable diseases (≥1,000 cases reported during the preceding year), and...

  12. Venezuela electoral 2012: escenarios y perspectivas

    Directory of Open Access Journals (Sweden)

    Juan Manuel Trak Vásquez

    2014-06-01

    Full Text Available El objetivo de estas líneas es reflexionar sobre los posibles escenarios que se pueden dar en Venezuela a partir de las elecciones presidenciales del 7 de octubre, en donde se juega la reelección de Hugo Chávez Frías (HCF. Para ello es necesario hacer un breve recorrido por la historia política reciente de Venezuela, cómo llega HCF al poder y los hitos más importantes que han marcado sus mandatos desde 1998.

  13. REGIONAL RECIPROCAL GUARANTEE SOCIETIES IN VENEZUELA

    Directory of Open Access Journals (Sweden)

    Orlando J. Canelones

    2014-11-01

    Full Text Available This research aims to describe the operation of services offered by the Regional Mutual Guarantee Societies (SGRs in Venezuela, and to present synthetically, the rudiments for constitution, as well as the legal basis that must rule them, through conducting an executive summary of the Law of the National System of Reciprocal Guarantees for Small and Medium Business and the Promotion, Constitution and Functioning Rules of National Mutual Funds and Guarantees and SGRs.  The methodology used in this research is documentary, through a literature review and exploration that allowed inferences about the importance of Regional SGRs in Venezuela, as financing alternative

  14. Venezuela: moving from abundance to moderation

    Energy Technology Data Exchange (ETDEWEB)

    Legros, E

    1984-06-01

    Venezuela is Latin America's second greatest oil producer and its dependence on oil production is extreme. Hydrocarbons account for over 90% of its foreign currency earnings, and oil revenue represents the bulk of the state's resources. Statistics on petroleum exploration, production, refining, consumption, and exports are given and related to the status quo and predicted development in Venezuela. The potential contribution of the Orinoco heavy crude oil reservoir is assessed. A decreased independence on oil production as an income market for the country is being sought.

  15. Venezuela slates second oil field revival round

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that Venezuela will accept bids under a second round next year from private foreign and domestic companies for production contracts to operate marginal active as well as inactive oil fields. The first such round came earlier this year, involving about 55 other marginal, inactive fields. It resulted in two contractors signed with domestic and foreign companies. It represented the first time since nationalization of the petroleum industry in Venezuela in 1976 that private companies were allowed to produce oil in the country. A public bid tender was expected at presstime last week

  16. Malaria in Sucre State, Venezuela

    Directory of Open Access Journals (Sweden)

    Robert H. Zimmerman

    2000-12-01

    Full Text Available The author reviews the malaria research program in Sucre State, Venezuela, taking an ecosystem approach. The goal was to determine which methods could have been introduced at the onset that would have made the study more ecological and interdisciplinary. Neither an ecosystem approach nor integrated disease control were in place at the time of the study. This study began to introduce an ecosystem approach when two contrasting ecosystems in Sucre State were selected for study and vector control methods were implemented based on research results. The need to have a health policy in place with an eco-health approach is crucial to the success of research and control. The review suggests that sustainability is low when not all the stakeholders are involved in the design and implementation of the research and control strategy development. The lack of community involvement makes sustainability doubtful. The author concludes that there were two interdependent challenges for malaria control: development of an ecosystem approach for malaria research and control, and the implementation of an integrated disease control strategy, with malaria as one of the important health issues.O autor faz uma revisão do programa de pesquisa sobre malária no Estado de Sucre, Venezuela, à luz de uma abordagem ecossistêmica. O objetivo era determinar quais métodos poderiam ter sido introduzidos no início do estudo para torná-lo mais ecológico e interdisciplinar. A fase inicial do estudo não incluía uma abordagem ecossistêmica ou controle integrado da doença, que só foram incorporados quando dois ecossistemas contrastantes no Estado de Sucre foram selecionados para pesquisa, junto com um método de controle de vetores com base nos resultados. Uma política de saúde bem-definida com uma abordagem ecossistêmica é crucial para o sucesso de uma estratégia de pesquisa e controle. Esta revisão sugere que a sustentabilidade é baixa se todos os atores não estiverem

  17. REPRODUCTIVE BIOLOGY OF THE VENEZUELA ROUND STINGRAY UROTRYGON VENEZUELAE SCHULTZ FROM THE COLOMBIAN CARIBBEAN

    Directory of Open Access Journals (Sweden)

    KELLY ACEVEDO

    2015-06-01

    Full Text Available As for most batoid species, little is known about the basic biology of the Venezuela round stingray Urotrygon venezuelae (Urotrygonidae. This study presents information about the reproductive biology of the species, including fecundity, embryonic development stage, relationship between maternal size and fecundity, gonadosomatic (GSI and hepatosomatic (HSI indices, sex ratios, maturity size and size at birth. With all this information, a preliminary reproductive cycle is proposed. A total of 269 specimens were caught with beach seine in Salguero beach, Colombian Caribbean Sea, between August 2005 and October 2006. We propose for U. venezuelae a biological cycle with three reproductive peaks: November-December, March-April and August. Size at sexual maturity was calculated in 176 mm (total length for females and 227 mm for males; fecundity ranged between one and six embryos per female. We found that cloacal diameter and liver weight were better predictors for fecundity than total length for U. venezuelae.

  18. 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.

  19. Nuclear power planning study for Venezuela. Estudio de planificacion nucleoelectrica para Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    The optimum capacity for nuclear power plants that might be built in Venezuela in the period 1985-2000 and the best time for incorporating them into the electric system is defined. The most recent forecasts regarding growth of the population and demand, and of the economy in general, and the taking into account the costs for the fossil-fuel and hydroelectric resources known to exist in Venezuela, as compared with the costs of importing uranium, are discussed.

  20. Doing Business Economy Profile 2015 : Venezuela, RB

    OpenAIRE

    World Bank Group

    2014-01-01

    This economy profile for Doing Business 2015 presents the 11 Doing Business indicators for Venezuela RB. To allow for useful comparison, the profile also provides data for other selected economies (comparator economies) for each indicator. Doing Business 2015 is the 12th edition in a series of annual reports measuring the regulations that enhance business activity and those that constrain ...

  1. Mastery: A Lesson from Maria in Venezuela

    Science.gov (United States)

    Powell, Sandra Anez; Powell, Norman W.

    2012-01-01

    Children who have been born into poverty or into at-risk circumstances are often considered "disposable" and not a societal priority. These youngsters have few advocates and limited successful options in life. In the city of Maracaibo, Venezuela, there is a large population of Amerindians who are called Guajiros. These indigenous people…

  2. Venezuela: Issues in the 111th Congress

    Science.gov (United States)

    2010-09-03

    Congressional Research Service 12 telecommunications, electricity, and steel companies, as well as cement, coffee , sugar, flour, and milk...poppy, and cannabis cultivation in the common Sierra de Perijá mountain area bordering the two countries. In 2008 and 2009, Venezuela installed 10

  3. Venezuela: Higher education, neoliberalism and socialism

    NARCIS (Netherlands)

    Muhr, T.; Verger, A.; Hill, David; Rosskam, Ellen

    2008-01-01

    In this chapter we analyse the Higher Education For All (HEFA) policies and practices in the Bolivarian Republic of Venezuela. In the construction of a 21st Century Socialism, universal access to higher education has not only become a constitutional right but assumes a pivotal role in both the

  4. 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.

  5. Nave de montaje Volkswagen, Venezuela

    Directory of Open Access Journals (Sweden)

    Bornhorst, D.

    1966-02-01

    Full Text Available To assemble Volkswagen cars for the Venezuela market, a large hall has been built, which is fitted with full facilities for its purpose, such as painting and greasing installations, and large parking area for the finished vehicles. The siting of this hall was carefully studied, and such factors as nearness to industrial zones, climate, and ease of access were decisive aspects that were taken into account. The final choice was a site near Morón, in the Carabobo Department, close to the sea. The main constructional item is the roof of the large hall. It is made of a series of hyperbolic-parabolic reinforced concrete thin shells, of rectangular planform, and slightly inclined towards the north, to produce a saw edge profile. Each of these shells is supported by a central column. The hollow spaces along the saw edge profile have been used for ventilation. The enclosing walls consist of trellice material, which also provide ample facility for additional ventilation.Para el montaje de los coches Volkswagen destinados al mercado venezolano, se ha construido una gran nave dotada de todos los servicios necesarios: pintura, engrases, aparcamiento de los vehículos terminados, etc. La elección del lugar más apropiado para la situación de la nave y edificios anexos fue motivo de un detenido estudio, en el que la proximidad a zonas industriales, clima, fácil entrada de materiales procedentes de ultramar y salida para los acabados, fueron los factores decisivos. Definitivamente se eligió un solar en las cercanías de Morón, del departamento de Carabobo, y próximo al mar. Lo más notable es la cubierta de la gran nave, formada por una serie de láminas parabólico-hiperbólicas de hormigón armado, de planta rectangular, inclinadas ligeramente hacia el norte para formar un perfil en diente de sierra. Cada una de estas láminas se soporta por un montante central. Los huecos que dichos dientes de sierra dejan se han aprovechado para la ventilación. Los

  6. Occupational Safety and Health in Venezuela.

    Science.gov (United States)

    Caraballo-Arias, Yohama

    2015-01-01

    Venezuela has pioneered a preventive-focused and comprehensive movement for Occupational Safety and Health (OSH) in Latin America. However, despite being an oil-rich country, it has some of the lowest salaries for their workers and highest levels of hyperinflation, devaluation, crime, and violence of the world. Review the current status and challenges on relevant aspects of OSH in Venezuela. Review of literature and documents from national governments, UN agencies, NGOs, and the Venezuelan government concerning OSH and related topics since 1986. Reformed in 2005, the Organic Law on Prevention, Conditions and Environment (LOPCYMAT) was a fundamental moment of change for OSH. Factors which have impacted OSH the strongest are (i) the creation of the National Institute of Occupational Safety and Health (INPSASEL) and (ii) the socioeconomic crisis Venezuela is going through. Venezuela's laws are innovative and yet non-compliance is enormous. Almost half of the population works in the informal sector. Following the International Labor Office projections, 5 people die per day in Venezuela due to occupational accidents or diseases, making health and safety at work a luxury rather than a right. The quality of life for the average worker has deteriorated, affecting not only health but the overall well-being of all Venezuelans. The political and socio-economic situation has led to a mass exodus of more than 1.6 million highly qualified and talented professionals. Many statistics concerning OSH are not updated and are unreliable regarding occupational accidents and diseases. There is a substantial difference between what is written to protect individual Venezuelans in the workplace and the reality of workplace conditions. Substantial governmental actions are needed in the immediate future to improve occupational safety and health of Venezuelan workers. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  7. 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?

  8. Decade of Venezuela’s President Hugo Chavez, Por Ahora

    Science.gov (United States)

    2009-04-01

    minor production source of opium and cocoa , Venezuela is important in the transit of narcotics between Columbia and the US. 60 61 Mindful of this, a...took over.91 To highlight the significance of oil to Venezuela , in 2006, oil represented 91% of its exports compared to 80% five years earlier.92...methodology to examine the last ten years of Venezuelas Hugo Chavez presidency and the significant aspects in terms of US security. The paper contents

  9. Plans to revive oil fields in Venezuela on track

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports on the three operating units of Venezuela's state owned oil company Petroleos de Venezuela SA which will begin receiving bids Feb. 28 from companies interested in operating 55 inactive oil fields in nine producing areas of Venezuela. Francisco Pradas, Pdvsa executive in charge of the program, the the company expects 88 companies or combines of foreign and domestic private companies to participate in the bidding. The program, announced last year, aims to reactivate production in marginal oil fields. It will involve the first direct participation by private companies in Venezuela's oil production since nationalization in 1976

  10. Astrometry and Geostationary Satellites in Venezuela

    Science.gov (United States)

    Lacruz, E.; Abad, C.

    2015-10-01

    We present the current status and the first results of the astrometric project CIDA - ABAE for tracking geo-stationary satellites. This project aims to determine a preliminary orbit for the Venezuelan satellite VENESAT-1, using astrometric positions obtained from an optical telescope. The results presented here are based on observations from the Luepa space tracking ground station in Venezuela, which were processed using astrometric procedures.

  11. National Oil Companies: the view from Venezuela

    International Nuclear Information System (INIS)

    Rodriguez, M.

    1994-01-01

    National oil companies were key elements in the initial OPEC strategy and they brought a de-integration of oil industry. These companies have tried to move from crude marketing to product marketing through new investments at home and abroad in order to get higher value added and more secure markets for crude. Low prices bring new challenges. Venezuela's answers are strategic associations, operating contract for marginal fields and profit sharing agreements. (Author)

  12. Zika virus disease

    Directory of Open Access Journals (Sweden)

    Adel I Al-Afaleq

    2017-01-01

    Full Text Available The Zika virus is an arbovirus belonging to the virus family Flaviviridae. The virus was isolated in 1947 from a rhesus monkey in the Zika Forest of Uganda. The virus causes sporadic mild human infections in Africa and later in Asia. However, by 2007 a major shift in its infection pattern was noticed and thousands of human infections were reported in the State of Yap and Federated States of Micronesia. In the last 3 years, major outbreaks have continued to occur and the virus has spread to several Pacific and American countries. These outbreaks were mostly asymptomatic; however, there were more severe clinical signs associated with the infections. Those signs included microcephaly and Guillain–Barre syndrome. It is believed that various species of mosquitoes can biologically transmit the virus. However, Aedes aegypti is most widely associated with the Zika virus. Recently, new modes of virus transmission have been reported, including mother-to-fetus, sexual, blood transfusion, animal bites, laboratory exposure and breast milk. Differential diagnosis is very important as some other arboviruses such as yellow fever virus, West Nile virus, dengue virus, and chikungunya virus have similar clinical manifestations to the Zika virus infection as well as relating serologically to some of these viruses. Established laboratory diagnostic tests to detect the Zika virus are limited, with reverse transcription polymerase chain reaction being the most widely used test. Taking into consideration the quickness of the spread of infection, size of the infected population and change of the infection severity pattern, the Zika virus infection merits collective efforts on all levels to prevent and control the disease. Limited research work and data, concurrent infection with other arboviruses, involvement of biological vectors, mass crowd events, human and trade movements and lack of vaccines are some of the challenges that we face in our efforts to prevent and

  13. Venezuela and Energy Security of Latin America

    Directory of Open Access Journals (Sweden)

    Elena Igorevna Vesnovskaya

    2015-12-01

    Full Text Available The article is devoted to the specificity of Venezuela's energy policy and the features of the evolution of its approaches to solving problems of energy security. Special attention is paid to the projects of Caracas in the energy sector which are aimed at the creating of common energy zone in Latin America. The author has revealed the interaction of internal political processes in Venezuela as the country's leader in the region, with its integration policy, and also identified trends in the further development of energy policy and strategy of Latin American countries. The research of energy resources of Latin America determined that the main factor that works in favor of convergence states within the South American "geopolitical ring" is to ensure energy security. Venezuela is among the richest resources of Latin America. In the research it was determined that Petrosur, Petrocaribe and Petroandina provide the basis for a range of bilateral agreements to promote cooperation, creation ventures based on the state oil companies of these states.

  14. 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

  15. Water balance dynamics in the Nile Basin

    Science.gov (United States)

    Senay, Gabriel B.; Asante, Kwabena; Artan, Guleid A.

    2009-01-01

    Understanding the temporal and spatial dynamics of key water balance components of the Nile River will provide important information for the management of its water resources. This study used satellite-derived rainfall and other key weather variables derived from the Global Data Assimilation System to estimate and map the distribution of rainfall, actual evapotranspiration (ETa), and runoff. Daily water balance components were modelled in a grid-cell environment at 0·1 degree (∼10 km) spatial resolution for 7 years from 2001 through 2007. Annual maps of the key water balance components and derived variables such as runoff and ETa as a percent of rainfall were produced. Generally, the spatial patterns of rainfall and ETa indicate high values in the upstream watersheds (Uganda, southern Sudan, and southwestern Ethiopia) and low values in the downstream watersheds. However, runoff as a percent of rainfall is much higher in the Ethiopian highlands around the Blue Nile subwatershed. The analysis also showed the possible impact of land degradation in the Ethiopian highlands in reducing ETa magnitudes despite the availability of sufficient rainfall. Although the model estimates require field validation for the different subwatersheds, the runoff volume estimate for the Blue Nile subwatershed is within 7·0% of a figure reported from an earlier study. Further research is required for a thorough validation of the results and their integration with ecohydrologic models for better management of water and land resources in the various Nile Basin ecosystems.

  16. 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,

  17. Epidemiology of West Nile in Europe and in the Mediterranean Basin

    OpenAIRE

    Calistri, Paolo; Giovannini, Armando; Hubalek, Zdenek; Ionescu, Aurelia; Monaco, Federica; Savini, Giovanni; Lelli, Rossella

    2010-01-01

    In the last 30 years several cases of West Nile (WN) virus infection were reported in horses and humans in Europe and in the Mediterranean Basin. Most of them were determined by strains of the Lineage 1 included in the European Mediterranean/Kenyan cluster. Strains of this cluster are characterised by a moderate pathogenicity for horses and humans and limited or no pathogenicity for birds. In recent years, however, WN cases determined by strains grouped in the Israeli/American cluster of Line...

  18. Critical Pedagogy and Empowering in Teacher Education in Venezuela.

    Science.gov (United States)

    Chacon, Carmen T.; Alvarez, Luisa Cristina

    This paper addresses the issue of the relationship between critical pedagogy and English as a foreign language (EFL) in Venezuela. Teacher-researchers have come to see the issues confronting nonnative educators in ELT as a more important issue than in previous years. They are particularly concerned about the current situation in Venezuela,…

  19. South America's energy integration overshadows Venezuela-US confrontational posture

    International Nuclear Information System (INIS)

    Abrantes, Dayse

    2006-01-01

    Venezuela's plans of a 10 000 km gas pipeline project spanning Latin America is presented. A brief analysis of Venezuela's petroleum industry is provided. President Hugo Chavez' main ambitions include reducing oil sales to the USA and to spark South America's energy integration

  20. Language Planning for Venezuela: The Role of English.

    Science.gov (United States)

    Kelsey, Irving; Serrano, Jose

    A rationale for teaching foreign languages in Venezuelan schools is discussed. An included sociolinguistic profile of Venezuela indicates that Spanish is the sole language of internal communication needs. Other languages spoken in Venezuela serve primarily a group function among the immigrant and indigenous communities. However, the teaching of…

  1. The Dairy Technology System in Venezuela. Summary of Research 79.

    Science.gov (United States)

    Nieto, Ruben D.; Henderson, Janet L.

    A study examined the agricultural technology system in Venezuela with emphasis on the dairy industry. An analytical framework was used to identify the strengths and weaknesses of the following components of Venezuela's agricultural technology system: policy, technology development, technology transfer, and technology use. Selected government…

  2. Emerging vector-borne diseases in dromedaries in Tunisia: West Nile, bluetongue, epizootic haemorrhagic disease and Rift Valley fever.

    Science.gov (United States)

    Hassine, Thameur B; Amdouni, Jihane; Monaco, Federica; Savini, Giovanni; Sghaier, Soufien; Selimen, Imed B; Chandoul, Walid; Hamida, Khaled B; Hammami, Salah

    2017-03-31

    A total of 118 sera were collected during 2016 from two groups of dromedaries from Kebili and Medenine governorates in the south of Tunisia. The aim of this study was to provide the first serological investigation of four emerging vector-borne diseases in two groups of dromedaries in Tunisia. Sera were tested by ELISA and serum neutralisation test to identify West Nile virus (WNV), bluetongue virus (BTV), epizootic haemorrhagic disease virus (EHDV) and Rift Valley fever virus (RVFV). In the first group, the seroprevalence for BTV was 4.6%, while in the second group, it was 25.8% for WNV and 9.7% for BTV. Only serotype 1 was detected for BTV in the two groups. No evidence for circulation of RVF and EHD viruses was revealed. Results indicated that dromedaries can be infected with BTV and WNV, suggesting that this species might play a significant role in the epizootiology of these viral diseases in Tunisia and neighbouring countries.

  3. Trends in fatal snakebites in Venezuela, 1995-2002.

    Science.gov (United States)

    Benítez, Jesús A; Rifakis, Pedro M; Vargas, Jair A; Cabaniel, Gilberto; Rodríguez-Morales, Alfonso J

    2007-01-01

    There have been few studies evaluating snakebite mortality in Venezuela and South America. In this study we evaluate trends in fatal snakebites occurring in Venezuela between 1995 and 2002. Epidemiological data for this study were retrieved from the records of the Ministry of Health of Venezuela. Using these data, we analyzed the impact of snakebites in Venezuela during the study period. During the study period, there were 266 reports of death due to snakebite; 79.7% were males, and 20.3% were females (P Mortality rate by age showed an age-dependent rate, with higher rates in older ages (P = .038). Snake envenomations are an important cause of injury and deaths in Venezuela as in many American countries. Surveillance of envenomations is essential for establishing guidelines, planning therapeutic supplies, and training medical staff on snakebite treatment, as well as assessing risk zones for travelers.

  4. [Seasonality of rotavirus infection in Venezuela: relationship between monthly rotavirus incidence and rainfall rates].

    Science.gov (United States)

    González Chávez, Rosabel

    2015-09-01

    In general, it has been reported that rotavirus infection was detected year round in tropical countries. However, studies in Venezuela and Brazil suggest a seasonal behavior of the infection. On the other hand, some studies link infection with climatic variables such as rainfall. This study analyzes the pattern of behavior of the rotavirus infection in Carabobo-Venezuela (2001-2005), associates the seasonality of the infection with rainfall, and according to the seasonal pattern, estimates the age of greatest risk for infection. The analysis of the rotavirus temporal series and accumulated precipitation was performed with the software SPSS. The infection showed two periods: high incidence (November-April) and low incidence (May-October). Accumulated precipitation presents an opposite behavior. The highest frequency of events (73.8% 573/779) for those born in the period with a low incidence of the virus was recorded at an earlier age (mean age 6.5 +/- 2.0 months) when compared with those born in the station of high incidence (63.5% 568/870, mean age 11.7 +/- 2.2 months). Seasonality of the infection and the inverse relationship between virus incidence and rainfall was demonstrated. In addition, it was found that the period of birth determines the age and risk of infection. This information generated during the preaccine period will be helpful to measure the impact of the vaccine against the rotavirus.

  5. Production of salinity tolerant Nile tilapia, Oreochromis niloticus ...

    African Journals Online (AJOL)

    Production of salinity tolerant Nile tilapia, Oreochromis niloticus through traditional and modern breeding methods: II. Application of genetically modified breeding by introducing foreign DNA into fish gonads.

  6. Ampharetidae Malmgren, 1867 (Annelida: Polychaeta from Venezuela

    Directory of Open Access Journals (Sweden)

    Ildefonso Liñero-Arana

    2012-06-01

    Full Text Available One hundred nineteen specimens of the family Ampharetidae Malmgren, collected in soft bottoms from 26 stations of the Venezuelan coast using PVC corer (0.018 m2, trawl and dredge van Veen (0.013 m3, were analyzed taxonomically. Five species were identified: Auchenoplax crinita Ehlers, 1887, Isolda pulchella F. Müller, 1858, Melinna maculata Webster, 1879, Amphicteis cf. scaphobranchiata Moore, 1906, and Hobsonia florida Banse, 1979; all are new records for Venezuela and extend the geographic distribution of these species.

  7. La calidad de vida urbana en Venezuela

    OpenAIRE

    Camargo Mora, María Gabriela

    2014-01-01

    En las últimas décadas Venezuela se ha caracterizado por un crecimiento alto que supera el 3% interanual, el cual al ser extrapolado al año 2005, refleja una tendencia a situarse alrededor del 2%, catalogado como crecimiento moderado, que de seguir a este ritmo de crecimiento la población tiende a quintuplicarse en la segunda mitad del siglo XX (Camargo, M., 1996). Dicho crecimiento poblacional ha estado acompañado de cambios en la distribución de la población, como resulta ser la concentraci...

  8. Kebijakan Politik Hugo Chavez Dalam Penanggulangan Krisis Ekonomi Venezuela (1998-2008)

    OpenAIRE

    Pinem, Try Edo Ati

    2015-01-01

    Hugo Chavez is the President of Venezuela who has an important role for change of political direction to resolve economic crisis in Venezuela with his Bolivarian Revolution. His political and economic policies able to cope with the bad condition in Venezuela. The purpose of this study was (1) to describe the condition of Venezuela when the economic crisis (2) Describe the Bolivarian Revolution (3) Describe the policies of Hugo Chavez in Venezuela tackling the economic crisis...

  9. [Colombians in Venezuela: myth and reality].

    Science.gov (United States)

    Bidegain Greising, G; Freitez Landaeta, A

    1988-08-01

    Figures of Colombian immigrants in Venezuela in the period 1981-1986 as well as the development of their socio-demographic profile and their integration into the labor market are analyzed by means of ad hoc tables drawn from a Sample Home Survey by the Oficina Central de Estadisticas e Informatica and information from the civil record office. It is estimated that in 1987 there are only half a million Colombians in Venezuela and, contrary to what is generally assumed, not only has the afflux decreased (3/4 of the Colombians entered before 1981), but also a return migration can be observed. Colombian immigration is not homogeneous, but is made up of different groups as far as their professional skills and occupations are concerned. The number of Colombians engaged in household service and those living in rural areas has decreased, but not the number of active farm workers. A greater proportion of Colombians engaged in trade and sales activities is observed, but artisans and skilled labor are still the majority.

  10. Nuevos significados de la democracia en Venezuela

    Directory of Open Access Journals (Sweden)

    Ingrid Karina Núñez Muñoz

    2013-01-01

    Full Text Available El objetivo de este trabajo es interpretar los nuevos significados de la demo- cracia en Venezuela, construidos a partir de los cambios y transformaciones iniciados en 1999 (proceso constituyente-reforma política, teniendo como centro los discursos y prácticas de una ciudadanía que debe participar de forma activa y organizada en los asuntos públicos con miras a la búsqueda de la solución de sus problemas más apremiantes. La aproximación metodológica (cualitativa-hermenéutica se realizó con- siderando que esta redefinición es una construcción intersubjetiva de los valores, acciones y normas en el ámbito político que intenta explicar cómo se construye la ciudadanía, fundamentalmente en el nivel local, a través de formas asociativas (como los consejos comunales en su interrelación con el Estado. Se concluye que a partir del nuevo orden constitucional de 1999 se comien- za a construir en Venezuela un nuevo sujeto que intenta viabilizar sus de- mandas a través de las organizaciones sociales.

  11. Lanzamiento de supermercados cheap en venezuela

    Directory of Open Access Journals (Sweden)

    Oscar A. Colmenares D.

    2008-01-01

    Full Text Available El presente caso de estudio se plantea en el contexto del sector de distribución de alimentos al detal en Venezuela en los años 2005 al 2007, el cual ha ostentado diversas mutaciones y cambios en función de las condiciones socioeconómicas del país y las tendencias globales. La cadena internacional de Supermercados Cheap, de origen tailandés, es una empresa dedicada a la distribución al menor de productos de consumo masivo, que estaba interesada en abrir operaciones comerciales en Latinoamérica tomando como país piloto a Venezuela. Para ello, quiere desarrollar una red de tiendas con marca y concepto propio adecuada a las características y exigencias del mercado local. En este sentido, debe diagnosticar el escenario de negocios y del mercado actual del sector y diseñar un plan de acción para cumplir con su objetivo.

  12. [Three phases of homicidal violence in Venezuela].

    Science.gov (United States)

    Briceño-León, Roberto

    2012-12-01

    Venezuela was considered one of the least violent countries in Latin America, however by 2010 it was among the countries with the highest homicide rate. This article analyzes the evolution of homicides in Venezuela between 1985 and 2010 and proposes the existence of three stages which correspond to trends in social and political institutions of the country. The first from 1985 to 1993, characterized by the looting of 1989 and the coups d'état of 1992, when for the first time the homicide rate rose from 8 to 20. The second phase from 1994 to 1998 was a recovery period of the institutional and political stability when the homicide rate remained constant at around 20. The third phase began in 1999 with the H Chavez government and the institutional destruction that comes with the Bolivarian revolution and caused an increase in the rate of 20 to 57 homicides per 100 thousand inhabitants. This article argues that the explanation for the changes in the phases is to be found in the transformation of social and political institutions.

  13. Nutritional composition and shelflife of the lake victoria nile perch ...

    African Journals Online (AJOL)

    Nile perch, the most important commercial fish species from the Lake Victoria fishery, contributes about 67% of Kenya's total annual fish export earnings. Despite the Nile perch being an important foreign exchange earner, little information is available on its nutritional composition and shelf life on ice, information that is ...

  14. Blood biochemical of nile crocodile ( Crocodylus niloticus ) in Kano ...

    African Journals Online (AJOL)

    This study investigates serum biochemistry of Nile crocodile from Kano Zoological Garden, Kano, Nigeria. Six (6) adult Nile crocodile (Crocodylus niloticus) were captured from crocodile pond. Blood was collected from post occipital sinus of the physically restrain crocodile and used for serum biochemical parameters.

  15. Viruses in reptiles.

    Science.gov (United States)

    Ariel, Ellen

    2011-09-21

    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.

  16. Pollution Sources in the nile and their environmental impacts

    International Nuclear Information System (INIS)

    Abd El- Bary, M.R.

    1999-01-01

    Over the past decades , the natural quality of water sources has been altered by the impact of various human activities and water uses. In Egypt, the Nile River which is considered as the main water source is still a recipient of most of the wastewater discharged by industrial effluents and several agriculture drains contains mixed wastes (sewage and industrial). These wastes includes a variety of pollutants which have considerable potential effect on both water ecosystem and human health. Monitoring of these pollutant is the first step for the improvement and protection of the Nile River .The Nile Research Institute designed a monitoring program includes collection and analysis of samples from 35 stations along the Nile River from Aswan to the Mediterranean Sea and from all points sources of pollution discharge their wastes into the Nile. The most important pollutant in these wastes are heavy metals, organic matters, inorganic compounds and micro organism causing disease

  17. Venezuela: Political Conditions and U.S. Policy

    National Research Council Canada - National Science Library

    Sullivan, Mark P; Olhero, Nelson

    2008-01-01

    Under the populist rule of President Hugo Ch vez, first elected in 1998 and most recently reelected to a six-year term in December 2006, Venezuela has undergone enormous political changes, with a new...

  18. Venezuela: Political Conditions and U.S. Policy

    National Research Council Canada - National Science Library

    Sullivan, Mark P; Olhero, Nelson

    2007-01-01

    Under the populist rule of President Hugo Ch vez, first elected in 1998 and most recently reelected to a six-year term in December 2006, Venezuela has undergone enormous political changes, with a new...

  19. Seasonal abundance and molecular identification of West Nile virus ...

    African Journals Online (AJOL)

    Federal Medical Centre, Microbiology Unit, Pathology Department. 2. University of Ibadan .... grouped and analyzed using statistical software SPSS 12.0. Results. A total of .... culex quinqueasciatus (Diptera: Culicidea) in Mexico city. Parasites ...

  20. Seasonal abundance and molecular identification of West Nile virus ...

    African Journals Online (AJOL)

    Methods: Mosquitoes belonging to the Culex pipens complex were captured in three different locations located within Abeokuta Metropolis between March 2012 and January 2013. Individual species were identified using morphometric methods. Amplification of the Ace2 gene by PCR confirmed morphormetric identification ...