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Sample records for valley fever ecology

  1. Valley fever

    Science.gov (United States)

    ... especially the first trimester) People of Native American, African, or Philippine descent may also get more severe ... that causes Valley fever) Chest x-ray Sputum culture Sputum smear (KOH test) Tests done for more ...

  2. Valley Fever

    Science.gov (United States)

    ... loss Headache Valley fever Symptoms & causes Diagnosis & treatment Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  3. Rift Valley fever Entomology, Ecology, and Outbreak Risk Factors

    Science.gov (United States)

    Rift Valley fever (RVF) is a mosquito-borne zoonotic disease of domestic ruminants and humans in Africa. The disease is most severe in cattle, sheep, and goats, and it causes high mortality in young animals and abortion in adults. Exotic aanimal breeds from areas where RVF is not endemic tend to be ...

  4. Ecological niche modelling of Rift Valley fever virus vectors in Baringo, Kenya

    Directory of Open Access Journals (Sweden)

    Alfred O. Ochieng

    2016-11-01

    Full Text Available Background: Rift Valley fever (RVF is a vector-borne zoonotic disease that has an impact on human health and animal productivity. Here, we explore the use of vector presence modelling to predict the distribution of RVF vector species under climate change scenario to demonstrate the potential for geographic spread of Rift Valley fever virus (RVFV. Objectives: To evaluate the effect of climate change on RVF vector distribution in Baringo County, Kenya, with an aim of developing a risk map for spatial prediction of RVF outbreaks. Methodology: The study used data on vector presence and ecological niche modelling (MaxEnt algorithm to predict the effect of climatic change on habitat suitability and the spatial distribution of RVF vectors in Baringo County. Data on species occurrence were obtained from longitudinal sampling of adult mosquitoes and larvae in the study area. We used present (2000 and future (2050 Bioclim climate databases to model the vector distribution. Results: Model results predicted potential suitable areas with high success rates for Culex quinquefasciatus, Culex univitattus, Mansonia africana, and Mansonia uniformis. Under the present climatic conditions, the lowlands were found to be highly suitable for all the species. Future climatic conditions indicate an increase in the spatial distribution of Cx. quinquefasciatus and M. africana. Model performance was statistically significant. Conclusion: Soil types, precipitation in the driest quarter, precipitation seasonality, and isothermality showed the highest predictive potential for the four species.

  5. Haemoragisk Rift Valley Fever

    DEFF Research Database (Denmark)

    Fabiansen, Christian; Thybo, Søren

    2007-01-01

    A case of fatal hemorrhagic Rift Valley fever during an epidemic in Kenya's North Eastern Province in January 2007 is described.......A case of fatal hemorrhagic Rift Valley fever during an epidemic in Kenya's North Eastern Province in January 2007 is described....

  6. Breathing Valley Fever

    Centers for Disease Control (CDC) Podcasts

    2014-02-04

    Dr. Duc Vugia, chief of the Infectious Diseases Branch in the California Department of Public Health, discusses Valley Fever.  Created: 2/4/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/5/2014.

  7. A Statistical Model of Rift Valley Fever Activity in Egypt

    National Research Council Canada - National Science Library

    John M. Drake; Ali N. Hassan; John C. Beier

    2013-01-01

    Rift Valley fever (RVF) is a viral disease of animals and humans and a global public health concern due to its ecological plasticity, adaptivity, and potential for spread to countries with a temperate climate...

  8. Ecological Niche Modeling and Land Cover Risk Areas for Rift Valley Fever Vector, Culex tritaeniorhynchus Giles in Jazan, Saudi Arabia

    OpenAIRE

    Sallam, Mohamed F.; Al Ahmed, Azzam M.; Abdel-Dayem, Mahmoud S.; Mohamed A R Abdullah

    2013-01-01

    BACKGROUND: The mosquito, Culex tritaeniorhynchus Giles is a prevalent and confirmed Rift Valley Fever virus (RVFV) vector. This vector, in association with Aedimorphus arabiensis (Patton), was responsible for causing the outbreak of 2000 in Jazan Province, Saudi Arabia. METHODOLOGY/PRINCIPAL FINDINGS: Larval occurrence records and a total of 19 bioclimatic and three topographic layers imported from Worldclim Database were used to predict the larval suitable breeding habitats for this vector ...

  9. Spatial Heterogeneity of Habitat Suitability for Rift Valley Fever Occurrence in Tanzania: An Ecological Niche Modelling Approach.

    Directory of Open Access Journals (Sweden)

    Calvin Sindato

    2016-09-01

    Full Text Available Despite the long history of Rift Valley fever (RVF in Tanzania, extent of its suitable habitat in the country remains unclear. In this study we investigated potential effects of temperature, precipitation, elevation, soil type, livestock density, rainfall pattern, proximity to wild animals, protected areas and forest on the habitat suitability for RVF occurrence in Tanzania.Presence-only records of 193 RVF outbreak locations from 1930 to 2007 together with potential predictor variables were used to model and map the suitable habitats for RVF occurrence using ecological niche modelling. Ground-truthing of the model outputs was conducted by comparing the levels of RVF virus specific antibodies in cattle, sheep and goats sampled from locations in Tanzania that presented different predicted habitat suitability values.Habitat suitability values for RVF occurrence were higher in the northern and central-eastern regions of Tanzania than the rest of the regions in the country. Soil type and precipitation of the wettest quarter contributed equally to habitat suitability (32.4% each, followed by livestock density (25.9% and rainfall pattern (9.3%. Ground-truthing of model outputs revealed that the odds of an animal being seropositive for RVFV when sampled from areas predicted to be most suitable for RVF occurrence were twice the odds of an animal sampled from areas least suitable for RVF occurrence (95% CI: 1.43, 2.76, p < 0.001.The regions in the northern and central-eastern Tanzania were more suitable for RVF occurrence than the rest of the regions in the country. The modelled suitable habitat is characterised by impermeable soils, moderate precipitation in the wettest quarter, high livestock density and a bimodal rainfall pattern. The findings of this study should provide guidance for the design of appropriate RVF surveillance, prevention and control strategies which target areas with these characteristics.

  10. Spatial Heterogeneity of Habitat Suitability for Rift Valley Fever Occurrence in Tanzania: An Ecological Niche Modelling Approach.

    Science.gov (United States)

    Sindato, Calvin; Stevens, Kim B; Karimuribo, Esron D; Mboera, Leonard E G; Paweska, Janusz T; Pfeiffer, Dirk U

    2016-09-01

    Despite the long history of Rift Valley fever (RVF) in Tanzania, extent of its suitable habitat in the country remains unclear. In this study we investigated potential effects of temperature, precipitation, elevation, soil type, livestock density, rainfall pattern, proximity to wild animals, protected areas and forest on the habitat suitability for RVF occurrence in Tanzania. Presence-only records of 193 RVF outbreak locations from 1930 to 2007 together with potential predictor variables were used to model and map the suitable habitats for RVF occurrence using ecological niche modelling. Ground-truthing of the model outputs was conducted by comparing the levels of RVF virus specific antibodies in cattle, sheep and goats sampled from locations in Tanzania that presented different predicted habitat suitability values. Habitat suitability values for RVF occurrence were higher in the northern and central-eastern regions of Tanzania than the rest of the regions in the country. Soil type and precipitation of the wettest quarter contributed equally to habitat suitability (32.4% each), followed by livestock density (25.9%) and rainfall pattern (9.3%). Ground-truthing of model outputs revealed that the odds of an animal being seropositive for RVFV when sampled from areas predicted to be most suitable for RVF occurrence were twice the odds of an animal sampled from areas least suitable for RVF occurrence (95% CI: 1.43, 2.76, p Tanzania were more suitable for RVF occurrence than the rest of the regions in the country. The modelled suitable habitat is characterised by impermeable soils, moderate precipitation in the wettest quarter, high livestock density and a bimodal rainfall pattern. The findings of this study should provide guidance for the design of appropriate RVF surveillance, prevention and control strategies which target areas with these characteristics.

  11. Ecological niche modeling and land cover risk areas for rift valley fever vector, culex tritaeniorhynchus giles in Jazan, Saudi Arabia.

    Science.gov (United States)

    Sallam, Mohamed F; Al Ahmed, Azzam M; Abdel-Dayem, Mahmoud S; Abdullah, Mohamed A R

    2013-01-01

    The mosquito, Culex tritaeniorhynchus Giles is a prevalent and confirmed Rift Valley Fever virus (RVFV) vector. This vector, in association with Aedimorphus arabiensis (Patton), was responsible for causing the outbreak of 2000 in Jazan Province, Saudi Arabia. Larval occurrence records and a total of 19 bioclimatic and three topographic layers imported from Worldclim Database were used to predict the larval suitable breeding habitats for this vector in Jazan Province using ArcGIS ver.10 and MaxEnt modeling program. Also, a supervised land cover classification from SPOT5 imagery was developed to assess the land cover distribution within the suitable predicted habitats. Eleven bioclimatic and slope attributes were found to be the significant predictors for this larval suitable breeding habitat. Precipitation and temperature were strong predictors of mosquito distribution. Among six land cover classes, the linear regression model (LM) indicated wet muddy substrate is significantly associated with high-very high suitable predicted habitats (R(2) = 73.7%, Pplanning effective mosquito surveillance and control programs by public health personnel and researchers.

  12. Ecological niche modeling and land cover risk areas for rift valley fever vector, culex tritaeniorhynchus giles in Jazan, Saudi Arabia.

    Directory of Open Access Journals (Sweden)

    Mohamed F Sallam

    Full Text Available BACKGROUND: The mosquito, Culex tritaeniorhynchus Giles is a prevalent and confirmed Rift Valley Fever virus (RVFV vector. This vector, in association with Aedimorphus arabiensis (Patton, was responsible for causing the outbreak of 2000 in Jazan Province, Saudi Arabia. METHODOLOGY/PRINCIPAL FINDINGS: Larval occurrence records and a total of 19 bioclimatic and three topographic layers imported from Worldclim Database were used to predict the larval suitable breeding habitats for this vector in Jazan Province using ArcGIS ver.10 and MaxEnt modeling program. Also, a supervised land cover classification from SPOT5 imagery was developed to assess the land cover distribution within the suitable predicted habitats. Eleven bioclimatic and slope attributes were found to be the significant predictors for this larval suitable breeding habitat. Precipitation and temperature were strong predictors of mosquito distribution. Among six land cover classes, the linear regression model (LM indicated wet muddy substrate is significantly associated with high-very high suitable predicted habitats (R(2 = 73.7%, P<0.05. Also, LM indicated that total dissolved salts (TDS was a significant contributor (R(2 = 23.9%, P<0.01 in determining mosquito larval abundance. CONCLUSION/SIGNIFICANCE: This model is a first step in understanding the spatial distribution of Cx. tritaeniorhynchus and consequently the risk of RVFV in Saudi Arabia and to assist in planning effective mosquito surveillance and control programs by public health personnel and researchers.

  13. Forecast and Outbreak of Rift valley fever in Sudan, 2007

    Science.gov (United States)

    Background Rift Valley fever (RVF) outbreaks occur during heavy rainfall in various sub-Saharan countries including Kenya, Somalia, and Tanzania and more recently in Saudi Arabia and Yemen. Given the wide geographic and ecological range of RVF virus, it is necessary to monitor large areas for condit...

  14. Airborne Dust Models in Valley Fever Research

    Science.gov (United States)

    Sprigg, W. A.; Galgiani, J. N.; Vujadinovic, M.; Pejanovic, G.; Vukovic, A. J.; Prasad, A. K.; Djurdjevic, V.; Nickovic, S.

    2011-12-01

    Dust storms (haboobs) struck Phoenix, Arizona, in 2011 on July 5th and again on July 18th. One potential consequence: an estimated 3,600 new cases of Valley Fever in Maricopa County from the first storm alone. The fungi, Coccidioides immitis, the cause of the respiratory infection, Valley Fever, lives in the dry desert soils of the American southwest and southward through Mexico, Central America and South America. The fungi become part of the dust storm and, a few weeks after inhalation, symptoms of Valley Fever may appear, including pneumonia-like illness, rashes, and severe fatigue. Some fatalities occur. Our airborne dust forecast system predicted the timing and extent of the storm, as it has done with other, often different, dust events. Atmosphere/land surface models can be part of public health services to reduce risk of Valley Fever and exacerbation of other respiratory and cardiovascular illness.

  15. Molecular Epidemiology of Rift Valley Fever Virus

    Science.gov (United States)

    Grobbelaar, Antoinette A.; Weyer, Jacqueline; Leman, Patricia A.; Kemp, Alan; Paweska, Janusz T.

    2011-01-01

    Phylogenetic relationships were examined for 198 Rift Valley fever virus isolates and 5 derived strains obtained from various sources in Saudi Arabia and 16 countries in Africa during a 67-year period (1944–2010). A maximum-likelihood tree prepared with sequence data for a 490-nt section of the Gn glycoprotein gene showed that 95 unique sequences sorted into 15 lineages. A 2010 isolate from a patient in South Africa potentially exposed to co-infection with live animal vaccine and wild virus was a reassortant. The potential influence of large-scale use of live animal vaccine on evolution of Rift Valley fever virus is discussed. PMID:22172568

  16. Diagnosis and Chemotherapy of Human Trypanosomiasis and Vector Ecology of Rift Valley and Congo-Crimean Hemorrhagic Fever in Kenya.

    Science.gov (United States)

    1994-01-27

    for antibodies to RVF virus from 34 sheep, 40 goats, 6 cows and 5 camels in Turkana District near Lake Turkana in 1991. Two animals, one sheep and one... Lake Turkana and from a seasonal roadside pool. These eggs conformed in size and appearance with eggs of Aedes mcintoshi. However, we were KETRI Final...to be widespread (12) with the highest RVF antibody prevalence rate in humans in Kenya found in the northwest in Turkana District (13). Rift Valley

  17. Rift Valley fever: A neglected zoonotic disease?

    Science.gov (United States)

    Rift Valley fever (RVF) is a serious viral disease of animals and humans in Africa and the Middle East that is transmitted by mosquitoes. First isolated in Kenya during an outbreak in 1930, subsequent outbreaks have had a significant impact on animal and human health, as well as national economies. ...

  18. Complete genome analysis of 33 ecologically and biologically diverse Rift Valley fever virus strains reveals widespread virus movement and low genetic diversity due to recent common ancestry.

    Science.gov (United States)

    Bird, Brian H; Khristova, Marina L; Rollin, Pierre E; Ksiazek, Thomas G; Nichol, Stuart T

    2007-03-01

    Rift Valley fever (RVF) virus is a mosquito-borne RNA virus responsible for large explosive outbreaks of acute febrile disease in humans and livestock in Africa with significant mortality and economic impact. The successful high-throughput generation of the complete genome sequence was achieved for 33 diverse RVF virus strains collected from throughout Africa and Saudi Arabia from 1944 to 2000, including strains differing in pathogenicity in disease models. While several distinct virus genetic lineages were determined, which approximately correlate with geographic origin, multiple exceptions indicative of long-distance virus movement have been found. Virus strains isolated within an epidemic (e.g., Mauritania, 1987, or Egypt, 1977 to 1978) exhibit little diversity, while those in enzootic settings (e.g., 1970s Zimbabwe) can be highly diverse. In addition, the large Saudi Arabian RVF outbreak in 2000 appears to have involved virus introduction from East Africa, based on the close ancestral relationship of a 1998 East African virus. Virus genetic diversity was low (approximately 5%) and primarily involved accumulation of mutations at an average of 2.9 x 10(-4) substitutions/site/year, although some evidence of RNA segment reassortment was found. Bayesian analysis of current RVF virus genetic diversity places the most recent common ancestor of these viruses in the late 1800s, the colonial period in Africa, a time of dramatic changes in agricultural practices and introduction of nonindigenous livestock breeds. In addition to insights into the evolution and ecology of RVF virus, these genomic data also provide a foundation for the design of molecular detection assays and prototype vaccines useful in combating this important disease.

  19. Haemorrhagic fevers and ecological perturbations.

    Science.gov (United States)

    Le Guenno, B

    1997-01-01

    Hemorrhagic fever is a clinical and imprecise definition for several different diseases. Their main common point is to be zoonoses. These diseases are due to several viruses which belong to different families. The Flaviviridae have been known for the longest time. They include the Amaril virus that causes yellow fever and is transported by mosquitoes. Viruses that have come to light more recently belong to three other families: Arenaviridae, Bunyaviridae, and Filoviridae. They are transmitted by rodents (hantaviruses and arenaviruses) or from unknown reservoirs (Ebola Marburg). The primary cause of most outbreaks of hemorrhagic fever viruses is ecological disruption resulting from human activities. The expansion of the world population perturbs ecosystems that were stable a few decades ago and facilitates contacts with animals carrying viruses pathogenic to humans. Another dangerous human activity is the development of hospitals with poor medical hygiene. Lassa, Crimean-Congo or Ebola outbreaks are mainly nosocomial. There are also natural environmental changes: the emergence of Sin Nombre in the U.S. resulted from heavier than usual rain and snow during spring 1993 in the Four Corners. Biological industries also present risks. In 1967, collection of organs from monkeys allowed the discovery in Marburg of a new family of viruses, the Filoviridae. Hemorrhagic fever viruses are cause for worry, and the avenues to reduce their toll are still limited.

  20. Rift Valley Fever Outbreak in Livestock, Mozambique, 2014

    Science.gov (United States)

    Coetzee, Peter; Mubemba, Benjamin; Nhambirre, Ofélia; Neves, Luis; Coetzer, J.A.W.; Venter, Estelle H.

    2016-01-01

    In early 2014, abortions and death of ruminants were reported on farms in Maputo and Gaza Provinces, Mozambique. Serologic analysis and quantitative and conventional reverse transcription PCR confirmed the presence of Rift Valley fever virus. The viruses belonged to lineage C, which is prevalent among Rift Valley fever viruses in southern Africa. PMID:27869589

  1. Valley Fever: Danger Lurking in a Dust Cloud

    Science.gov (United States)

    Johnson, Larry; Gaab, Erin M.; Sanchez, Javier; Bui, Phuong Q.; Nobile, Clarissa J.; Hoyer, Katrina K.; Peterson, Michael W.; Ojcius, David M.

    2014-01-01

    Coccidioides immitis and Coccidioides posadasii contribute to the development of Valley Fever. The ability of these fungal pathogens to evade the host immune system creates difficulty in recognition and treatment of this debilitating infection. In this review, we describe the current knowledge of Valley Fever and approaches to improve prevention, detection, and treatment. PMID:25038397

  2. An epidemiological model of Rift Valley fever

    Directory of Open Access Journals (Sweden)

    Nicole P. Leahy

    2007-08-01

    Full Text Available We present and explore a novel mathematical model of the epidemiology of Rift Valley Fever (RVF. RVF is an Old World, mosquito-borne disease affecting both livestock and humans. The model is an ordinary differential equation model for two populations of mosquito species, those that can transmit vertically and those that cannot, and for one livestock population. We analyze the model to find the stability of the disease-free equlibrium and test which model parameters affect this stability most significantly. This model is the basis for future research into the predication of future outbreaks in the Old World and the assessment of the threat of introduction into the New World.

  3. Rift Valley Fever, Sudan, 2007 and 2010

    Science.gov (United States)

    Aradaib, Imadeldin E.; Erickson, Bobbie R.; Elageb, Rehab M.; Khristova, Marina L.; Carroll, Serena A.; Elkhidir, Isam M.; Karsany, Mubarak E.; Karrar, AbdelRahim E.; Elbashir, Mustafa I.

    2013-01-01

    To elucidate whether Rift Valley fever virus (RVFV) diversity in Sudan resulted from multiple introductions or from acquired changes over time from 1 introduction event, we generated complete genome sequences from RVFV strains detected during the 2007 and 2010 outbreaks. Phylogenetic analyses of small, medium, and large RNA segment sequences indicated several genetic RVFV variants were circulating in Sudan, which all grouped into Kenya-1 or Kenya-2 sublineages from the 2006–2008 eastern Africa epizootic. Bayesian analysis of sequence differences estimated that diversity among the 2007 and 2010 Sudan RVFV variants shared a most recent common ancestor circa 1996. The data suggest multiple introductions of RVFV into Sudan as part of sweeping epizootics from eastern Africa. The sequences indicate recent movement of RVFV and support the need for surveillance to recognize when and where RVFV circulates between epidemics, which can make data from prediction tools easier to interpret and preventive measures easier to direct toward high-risk areas. PMID:23347790

  4. Impact of Global Climate on Rift Valley Fever Disease Outbreaks

    Science.gov (United States)

    Rift Valley fever is a viral disease of animals and humans in Africa and the Middle East that is transmitted by mosquitoes. Since the virus was first isolated in Kenya in 1930 it has caused significant impact to animal and human health and national economies, and it is of concern to the internationa...

  5. A skin test survey of valley fever in Tijuana, Mexico.

    Science.gov (United States)

    Fredrich, B E

    1989-01-01

    Results of a study of the prevalence of valley fever among 1128 residents of Tijuana, Baja California are presented. Children from primary and middle schools (n = 497) and adults from technical institutes and maquiladoras (assembly plants) were tested for reaction to both spherulin and coccidioidin during 1985-1986, and they completed a questionnaire containing 23 variables on their socio-environment. Place of residence was mapped. The population sampled is largely middle class. Discriminant analysis indicates the distribution of positive cases is not clustered, nor can it be correlated with geomorphic factors such as mesa tops, canyons, or valley bottoms.

  6. Re-Emergence of Rift Valley Fever in Madagascar

    Centers for Disease Control (CDC) Podcasts

    2010-05-27

    This podcast describes the re-emergence of Rift Valley Fever in Madagascar during two rainy seasons in 2008 and 2009. CDC epidemiologist Dr. Pierre Rollin discusses what researchers learned about the outbreak and about infections in the larger population in Madagascar.  Created: 5/27/2010 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 5/27/2010.

  7. Statistical modeling of valley fever data in Kern County, California.

    Science.gov (United States)

    Talamantes, Jorge; Behseta, Sam; Zender, Charles S

    2007-03-01

    Coccidioidomycosis (valley fever) is a fungal infection found in the southwestern US, northern Mexico, and some places in Central and South America. The fungus that causes it (Coccidioides immitis) is normally soil-dwelling but, if disturbed, becomes air-borne and infects the host when its spores are inhaled. It is thus natural to surmise that weather conditions that foster the growth and dispersal of the fungus must have an effect on the number of cases in the endemic areas. We present here an attempt at the modeling of valley fever incidence in Kern County, California, by the implementation of a generalized auto regressive moving average (GARMA) model. We show that the number of valley fever cases can be predicted mainly by considering only the previous history of incidence rates in the county. The inclusion of weather-related time sequences improves the model only to a relatively minor extent. This suggests that fluctuations of incidence rates (about a seasonally varying background value) are related to biological and/or anthropogenic reasons, and not so much to weather anomalies.

  8. Molecular Epidemiology and Emergence of Rift Valley Fever

    Directory of Open Access Journals (Sweden)

    Sall AA

    1998-01-01

    Full Text Available Rift Valley fever (RVF is a mosquito-borne viral disease which manifested itself during recent epidemics and revealed its significant potential of emergence. Studies on molecular epidemiology undertaken to better understand the factors leading to RVF emergence, have confirmed the mode of circulation of the virus and highlithted probable risks and obstacles for prevention and control. As for several other viral agents, molecular epidemiology is becoming a useful tool in the study of the emergence of RVF as a serious infectious disease.

  9. An Epidemiological Model of Rift Valley Fever with Spatial Dynamics

    Directory of Open Access Journals (Sweden)

    Tianchan Niu

    2012-01-01

    Full Text Available As a category A agent in the Center for Disease Control bioterrorism list, Rift Valley fever (RVF is considered a major threat to the United States (USA. Should the pathogen be intentionally or unintentionally introduced to the continental USA, there is tremendous potential for economic damages due to loss of livestock, trade restrictions, and subsequent food supply chain disruptions. We have incorporated the effects of space into a mathematical model of RVF in order to study the dynamics of the pathogen spread as affected by the movement of humans, livestock, and mosquitoes. The model accounts for the horizontal transmission of Rift Valley fever virus (RVFV between two mosquito and one livestock species, and mother-to-offspring transmission of virus in one of the mosquito species. Space effects are introduced by dividing geographic space into smaller patches and considering the patch-to-patch movement of species. For each patch, a system of ordinary differential equations models fractions of populations susceptible to, incubating, infectious with, or immune to RVFV. The main contribution of this work is a methodology for analyzing the likelihood of pathogen establishment should an introduction occur into an area devoid of RVF. Examples are provided for general and specific cases to illustrate the methodology.

  10. Remote Sensing Contributions to Prediction and Risk Assessment of Natural Disasters Caused by Large Scale Rift Valley Fever Outbreaks

    Science.gov (United States)

    Anyamba, Assaf; Linthicum, Kenneth J.; Small, Jennifer; Britch, S. C.; Tucker, C. J.

    2012-01-01

    Remotely sensed vegetation measurements for the last 30 years combined with other climate data sets such as rainfall and sea surface temperatures have come to play an important role in the study of the ecology of arthropod-borne diseases. We show that epidemics and epizootics of previously unpredictable Rift Valley fever are directly influenced by large scale flooding associated with the El Ni o/Southern Oscillation. This flooding affects the ecology of disease transmitting arthropod vectors through vegetation development and other bioclimatic factors. This information is now utilized to monitor, model, and map areas of potential Rift Valley fever outbreaks and is used as an early warning system for risk reduction of outbreaks to human and animal health, trade, and associated economic impacts. The continuation of such satellite measurements is critical to anticipating, preventing, and managing disease epidemics and epizootics and other climate-related disasters.

  11. Innate Immune Response to Rift Valley Fever Virus in Goats

    Science.gov (United States)

    Nfon, Charles K.; Marszal, Peter; Zhang, Shunzhen; Weingartl, Hana M.

    2012-01-01

    Rift Valley fever (RVF), a re-emerging mosquito-borne disease of ruminants and man, was endemic in Africa but spread to Saudi Arabia and Yemen, meaning it could spread even further. Little is known about innate and cell-mediated immunity to RVF virus (RVFV) in ruminants, which is knowledge required for adequate vaccine trials. We therefore studied these aspects in experimentally infected goats. We also compared RVFV grown in an insect cell-line and that grown in a mammalian cell-line for differences in the course of infection. Goats developed viremia one day post infection (DPI), which lasted three to four days and some goats had transient fever coinciding with peak viremia. Up to 4% of peripheral blood mononuclear cells (PBMCs) were positive for RVFV. Monocytes and dendritic cells in PBMCs declined possibly from being directly infected with virus as suggested by in vitro exposure. Infected goats produced serum IFN-γ, IL-12 and other proinflammatory cytokines but not IFN-α. Despite the lack of IFN-α, innate immunity via the IL-12 to IFN-γ circuit possibly contributed to early protection against RVFV since neutralising antibodies were detected after viremia had cleared. The course of infection with insect cell-derived RVFV (IN-RVFV) appeared to be different from mammalian cell-derived RVFV (MAM-RVFV), with the former attaining peak viremia faster, inducing fever and profoundly affecting specific immune cell subpopulations. This indicated possible differences in infections of ruminants acquired from mosquito bites relative to those due to contact with infectious material from other animals. These differences need to be considered when testing RVF vaccines in laboratory settings. PMID:22545170

  12. Data-driven modeling to assess receptivity for Rift Valley Fever virus

    National Research Council Canada - National Science Library

    Barker, Christopher M; Niu, Tianchan; Reisen, William K; Hartley, David M

    2013-01-01

    Rift Valley Fever virus (RVFV) is an enzootic virus that causes extensive morbidity and mortality in domestic ruminants in Africa, and it has shown the potential to invade other areas such as the Arabian Peninsula...

  13. A hierarchical network approach for modeling Rift Valley fever epidemics with applications in North America

    National Research Council Canada - National Science Library

    Xue, Ling; Cohnstaedt, Lee W; Scott, H Morgan; Scoglio, Caterina

    2013-01-01

    .... In the event Rift Valley fever virus is introduced to the United States or other non-endemic areas, understanding the potential patterns of spread and the areas at risk based on disease vectors...

  14. Data-Driven Modeling to Assess Receptivity for Rift Valley Fever Virus: e2515

    National Research Council Canada - National Science Library

    Christopher M Barker; Tianchan Niu; William K Reisen; David M Hartley

    2013-01-01

      Rift Valley Fever virus (RVFV) is an enzootic virus that causes extensive morbidity and mortality in domestic ruminants in Africa, and it has shown the potential to invade other areas such as the Arabian Peninsula...

  15. A dynamic, climate-driven model of Rift Valley fever

    Directory of Open Access Journals (Sweden)

    Joseph Leedale

    2016-03-01

    Full Text Available Outbreaks of Rift Valley fever (RVF in eastern Africa have previously occurred following specific rainfall dynamics and flooding events that appear to support the emergence of large numbers of mosquito vectors. As such, transmission of the virus is considered to be sensitive to environmental conditions and therefore changes in climate can impact the spatiotemporal dynamics of epizootic vulnerability. Epidemiological information describing the methods and parameters of RVF transmission and its dependence on climatic factors are used to develop a new spatio-temporal mathematical model that simulates these dynamics and can predict the impact of changes in climate. The Liverpool RVF (LRVF model is a new dynamic, process-based model driven by climate data that provides a predictive output of geographical changes in RVF outbreak susceptibility as a result of the climate and local livestock immunity. This description of the multi-disciplinary process of model development is accessible to mathematicians, epidemiological modellers and climate scientists, uniting dynamic mathematical modelling, empirical parameterisation and state-of-the-art climate information.

  16. An Assembly Model of Rift Valley Fever Virus

    Science.gov (United States)

    Rusu, Mirabela; Bonneau, Richard; Holbrook, Michael R.; Watowich, Stanley J.; Birmanns, Stefan; Wriggers, Willy; Freiberg, Alexander N.

    2012-01-01

    Rift Valley fever virus (RVFV) is a bunyavirus endemic to Africa and the Arabian Peninsula that infects humans and livestock. The virus encodes two glycoproteins, Gn and Gc, which represent the major structural antigens and are responsible for host cell receptor binding and fusion. Both glycoproteins are organized on the virus surface as cylindrical hollow spikes that cluster into distinct capsomers with the overall assembly exhibiting an icosahedral symmetry. Currently, no experimental three-dimensional structure for any entire bunyavirus glycoprotein is available. Using fold recognition, we generated molecular models for both RVFV glycoproteins and found significant structural matches between the RVFV Gn protein and the influenza virus hemagglutinin protein and a separate match between RVFV Gc protein and Sindbis virus envelope protein E1. Using these models, the potential interaction and arrangement of both glycoproteins in the RVFV particle was analyzed, by modeling their placement within the cryo-electron microscopy density map of RVFV. We identified four possible arrangements of the glycoproteins in the virion envelope. Each assembly model proposes that the ectodomain of Gn forms the majority of the protruding capsomer and that Gc is involved in formation of the capsomer base. Furthermore, Gc is suggested to facilitate intercapsomer connections. The proposed arrangement of the two glycoproteins on the RVFV surface is similar to that described for the alphavirus E1-E2 proteins. Our models will provide guidance to better understand the assembly process of phleboviruses and such structural studies can also contribute to the design of targeted antivirals. PMID:22837754

  17. An assembly model of Rift Valley fever virus

    Directory of Open Access Journals (Sweden)

    Mirabela eRusu

    2012-07-01

    Full Text Available Rift Valley fever virus (RVFV is a bunyavirus endemic to Africa and the Arabian Peninsula that infects humans and livestock. The virus encodes two glycoproteins, Gn and Gc, which represent the major structural antigens and are responsible for host cell receptor binding and fusion. Both glycoproteins are organized on the virus surface as cylindrical hollow spikes that cluster into distinct capsomers with the overall assembly exhibiting an icosahedral symmetry. Currently, no experimental three-dimensional structure for any entire bunyavirus glycoprotein is available. Using fold recognition, we generated molecular models for both RVFV glycoproteins and found significant structural matches between the RVFV Gn protein and the influenza virus hemagglutinin protein and a separate match between RVFV Gc protein and Sindbis virus envelope protein E1. Using these models, the potential interaction and arrangement of both glycoproteins in the RVFV particle was analyzed, by modeling their placement within the cryo-electron microscopy density map of RVFV. We identified four possible arrangements of the glycoproteins in the virion envelope. Each assembly model proposes that the ectodomain of Gn forms the majority of the protruding capsomer and that Gc is involved in formation of the capsomer base. Furthermore, Gc is suggested to facilitate intercapsomer connections. The proposed arrangement of the two glycoproteins on the RVFV surface is similar to that described for the alphavirus E1-E2 proteins. Our models will provide guidance to better understand the assembly process of phleboviruses and such structural studies can also contribute to the design of targeted antivirals.

  18. Integrative Medicine Preferences Among Coccidioidomycosis (Valley Fever) Patients.

    Science.gov (United States)

    Short, Jack H; Bradley, Constance; Blair, Janis E; Stewart, Terry D; Burns, Mark W; Patron, Roberto L; Millstine, Denise M

    2017-02-01

    To understand the extent and modalities of integrative medicine strategies that patients with coccidioidomycosis (valley fever) have incorporated into their treatment regimens. A direct patient survey was distributed, with 100 unique responses, at a single infectious diseases clinic at an academic medical center in Arizona. Eligible patients, defined as those with confirmed coccidioidomycosis or currently under evaluation, were polled on their personal use of 36 integrative medicine modalities. Patients were also asked to indicate their level of fatigue on a 10-point scale in an attempt to correlate levels of fatigue to use of specific integrative medicine modalities. Of the patients surveyed, 64% had used at least one integrative medicine modality, and 53% used two or more, along with conventional medical therapy. The top three modalities were nutrition (39%), massage (27%), and breathing exercises (26%). The mean reported fatigue level was 4.7 on a 10-point scale, with a standard deviation of 3.0. There was no statistically significant association between use of a specific modality and reported level of fatigue. Nearly two thirds of patients (64%) surveyed had used at least one integrative medicine modality throughout the course of their therapy. Clinicians are probably unaware of the extent to which many patients, including this population, have embraced integrative medicine. Awareness of patients' goal and preferences is valuable in shared clinical decision making.

  19. Functional ecology of an Antarctic Dry Valley

    Science.gov (United States)

    Chan, Yuki; Van Nostrand, Joy D.; Zhou, Jizhong; Pointing, Stephen B.

    2013-01-01

    The McMurdo Dry Valleys are the largest ice-free region in Antarctica and are critically at risk from climate change. The terrestrial landscape is dominated by oligotrophic mineral soils and extensive exposed rocky surfaces where biota are largely restricted to microbial communities, although their ability to perform the majority of geobiological processes has remained largely uncharacterized. Here, we identified functional traits that drive microbial survival and community assembly, using a metagenomic approach with GeoChip-based functional gene arrays to establish metabolic capabilities in communities inhabiting soil and rock surface niches in McKelvey Valley. Major pathways in primary metabolism were identified, indicating significant plasticity in autotrophic, heterotrophic, and diazotrophic strategies supporting microbial communities. This represents a major advance beyond biodiversity surveys in that we have now identified how putative functional ecology drives microbial community assembly. Significant differences were apparent between open soil, hypolithic, chasmoendolithic, and cryptoendolithic communities. A suite of previously unappreciated Antarctic microbial stress response pathways, thermal, osmotic, and nutrient limitation responses were identified and related to environmental stressors, offering tangible clues to the mechanisms behind the enduring success of microorganisms in this seemingly inhospitable terrain. Rocky substrates exposed to larger fluctuations in environmental stress supported greater functional diversity in stress-response pathways than soils. Soils comprised a unique reservoir of genes involved in transformation of organic hydrocarbons and lignin-like degradative pathways. This has major implications for the evolutionary origin of the organisms, turnover of recalcitrant substrates in Antarctic soils, and predicting future responses to anthropogenic pollution. PMID:23671121

  20. Functional ecology of an Antarctic Dry Valley.

    Science.gov (United States)

    Chan, Yuki; Van Nostrand, Joy D; Zhou, Jizhong; Pointing, Stephen B; Farrell, Roberta L

    2013-05-28

    The McMurdo Dry Valleys are the largest ice-free region in Antarctica and are critically at risk from climate change. The terrestrial landscape is dominated by oligotrophic mineral soils and extensive exposed rocky surfaces where biota are largely restricted to microbial communities, although their ability to perform the majority of geobiological processes has remained largely uncharacterized. Here, we identified functional traits that drive microbial survival and community assembly, using a metagenomic approach with GeoChip-based functional gene arrays to establish metabolic capabilities in communities inhabiting soil and rock surface niches in McKelvey Valley. Major pathways in primary metabolism were identified, indicating significant plasticity in autotrophic, heterotrophic, and diazotrophic strategies supporting microbial communities. This represents a major advance beyond biodiversity surveys in that we have now identified how putative functional ecology drives microbial community assembly. Significant differences were apparent between open soil, hypolithic, chasmoendolithic, and cryptoendolithic communities. A suite of previously unappreciated Antarctic microbial stress response pathways, thermal, osmotic, and nutrient limitation responses were identified and related to environmental stressors, offering tangible clues to the mechanisms behind the enduring success of microorganisms in this seemingly inhospitable terrain. Rocky substrates exposed to larger fluctuations in environmental stress supported greater functional diversity in stress-response pathways than soils. Soils comprised a unique reservoir of genes involved in transformation of organic hydrocarbons and lignin-like degradative pathways. This has major implications for the evolutionary origin of the organisms, turnover of recalcitrant substrates in Antarctic soils, and predicting future responses to anthropogenic pollution.

  1. Response to Rift Valley Fever in Tanzania: Challenges and Opportunities.

    Science.gov (United States)

    Fyumagwa, Robert D; Ezekiel, Mangi J; Nyaki, Athanas; Mdaki, Maulid L; Katale, Zablon B; Moshiro, Candida; Keyyu, Julius D

    2011-12-01

    Rift Valley Fever (RVF) is an arthropod borne viral disease affecting livestock (cattle, sheep, goats and camels), wildlife and humans caused by Phlebovirus. The disease occurs in periodic cycles of 4-15 years associated with flooding from unusually high precipitations in many flood-prone habitats. Aedes and Culex spp and other mosquito species are important epidemic vectors. Because of poor living conditions and lack of knowledge on the pathogenesis of RVF, nomadic pastoralists and agro-pastoralists are at high risk of contracting the disease during epidemics. RVF is a professional hazard for health and livestock workers because of poor biosafety measures in routine activities including lack of proper Personal Protective Equipment (PPE). Direct exposure to infected animals can occur during handling and slaughter or through veterinary and obstetric procedures or handling of specimens in laboratory. The episodic nature of the disease creates special challenges for its mitigation and control and many of the epidemics happen when the governments are not prepared and have limited resource to contain the disease at source. Since its first description in 1930s Tanzania has recorded six epidemics, three of which were after independence in 1961. However, the 2007 epidemic was the most notable and wide spread with fatal human cases among pastoralists and agro-pastoralists concurrent with high livestock mortality. Given all the knowledge that exist on the epidemiology of the disease, still the 2006/2007 epidemic occurred when the government of Tanzania was not prepared to contain the disease at source. This paper reviews the epidemiology, reporting and outbreak-investigation, public awareness, preparedness plans and policy as well as challenges for its control in Tanzania.

  2. Rift Valley fever: Real or perceived threat for Zambia?

    Directory of Open Access Journals (Sweden)

    George Dautu

    2012-06-01

    Full Text Available Rift Valley fever (RVF in Zambia was first reported in 1974 during an epizootic of cattle and sheep that occurred in parts of Central, Southern and Copperbelt Provinces. In 1990, the disease was documented in nine districts of the provinces of Zambia. In the last two decades, there have been no reports of RVF. This long period without reported clinical disease raises questions as to whether RVF is a current or just a perceived threat. To address this question, World Organisation for Animal Health (OIE disease occurrence data on RVF for the period 2005−2010 in the Southern Africa Development Community (SADC was analysed. From the analysis, it was evident that most countries that share a common border with Zambia had reported at least one occurrence of the disease during the period under review. Due to the absence of natural physical barriers between Zambia and most of her neighbours, informal livestock trade and movements is a ubiquitous reality. Analysis of the rainfall patterns also showed that Zambia received rains sufficient to support a mosquito population large enough for high risk of RVF transmission. The evidence of disease occurrence in nearby countries coupled with animal movement, and environmental risk suggests that RVF is a serious threat to Zambia. In conclusion, the current occurrence of RVF in Zambia is unclear, but there are sufficient indications that the magnitude of the circulating infection is such that capacity building in disease surveillance and courses on recognition of the disease for field staff is recommended. Given the zoonotic potential of RVF, these measures are also a prerequisite for accurate assessment of the disease burden in humans.

  3. The 2007 Rift Valley Fever Outbreak in Sudan

    Science.gov (United States)

    Hassan, Osama Ahmed; Ahlm, Clas; Sang, Rosemary; Evander, Magnus

    2011-01-01

    Rift Valley fever (RVF) is a neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health and economy. RVF is caused by RVF virus (RVFV) affecting humans and a wide range of animals. The virus is transmitted through bites from mosquitoes and exposure to viremic blood, body fluids, or tissues of infected animals. During 2007 a large RVF outbreak occurred in Sudan with a total of 747 confirmed human cases including 230 deaths (case fatality 30.8%); although it has been estimated 75,000 were infected. It was most severe in White Nile, El Gezira, and Sennar states near to the White Nile and the Blue Nile Rivers. Notably, RVF was not demonstrated in livestock until after the human cases appeared and unfortunately, there are no records or reports of the number of affected animals or deaths. Ideally, animals should serve as sentinels to prevent loss of human life, but the situation here was reversed. Animal contact seemed to be the most dominant risk factor followed by animal products and mosquito bites. The Sudan outbreak followed an unusually heavy rainfall in the country with severe flooding and previous studies on RVF in Sudan suggest that RVFV is endemic in parts of Sudan. An RVF outbreak results in human disease, but also large economic loss with an impact beyond the immediate influence on the directly affected agricultural producers. The outbreak emphasizes the need for collaboration between veterinary and health authorities, entomologists, environmental specialists, and biologists, as the best strategy towards the prevention and control of RVF. PMID:21980543

  4. Rift Valley fever: current challenges and future prospects

    Directory of Open Access Journals (Sweden)

    Himeidan YE

    2016-03-01

    Full Text Available Yousif E Himeidan Vector Control Unit, Africa Technical Research Centre, Vector Health International, Arusha, Tanzania Abstract: Rift Valley fever (RVF is a zoonotic, mosquito-borne viral disease that affects human health and causes significant losses in the livestock industry. Recent outbreaks have led to severe human infections with high mortality rates. There are many challenges to applying effective preventive and control measures, including weak infrastructure of health facilities, lack of capacity and support systems for field logistics and communication, access to global expert organizations, and insufficient information on the epidemiological and reservoir status of the RVF virus. The health systems in East African countries are underdeveloped, with gaps in adaptability to new, more accurate and rapid techniques, and well-trained staff that affect their capacity to monitor and evaluate the disease. Surveillance and response systems are inadequate in providing accurate information in a timely manner for decision making to deal with the scope of interrupting the disease transmission by applying mass animal vaccination, and other preventive measures at the early stage of an outbreak. The historical vaccines are unsuitable for use in newborn and gestating livestock, and the recent ones require a booster and annual revaccination. Future live-attenuated RVF vaccines should possess lower safety concerns regardless of the physiologic state of the animal, and provide rapid and long-term immunity after a single dose of vaccination. In the absence of an effective vaccination program, prevention and control measures must be immediately undertaken after an alert is generated. These measures include enforcing and adapting standard protocols for animal trade and movement, extensive vector control, safe disposal of infected animals, and modification of human–animal contact behavior. Directing control efforts on farmers and workers who deal with

  5. A Systematic Scoping Study of the Socio-Economic Impact of Rift Valley Fever

    NARCIS (Netherlands)

    Peyre, M.; Chevalier, V.; Abdo-Salem, S.; Velthuis, A.; Antoine-Moussiaux, N.; Thiry, E.; Roger, F.

    2015-01-01

    Rift Valley fever (RVF) is a severe mosquito-borne disease affecting humans and domestic ruminants. RVF virus has been reported in most African countries, as well as in the Arabic Peninsula. This paper reviews the different types of socio-economic impact induced by RVF disease and the attempts to

  6. Regional dust storm modeling for health services: The case of valley fever

    Science.gov (United States)

    Sprigg, William A.; Nickovic, Slobodan; Galgiani, John N.; Pejanovic, Goran; Petkovic, Slavko; Vujadinovic, Mirjam; Vukovic, Ana; Dacic, Milan; DiBiase, Scott; Prasad, Anup; El-Askary, Hesham

    2014-09-01

    On 5 July 2011, a massive dust storm struck Phoenix, Arizona (USA), raising concerns for increased cases of valley fever (coccidioidomycosis, or, cocci). A quasi-operational experimental airborne dust forecast system predicted the event and provides model output for continuing analysis in collaboration with public health and air quality communities. An objective of this collaboration was to see if a signal in cases of valley fever in the region could be detected and traced to the storm - an American haboob. To better understand the atmospheric life cycle of cocci spores, the DREAM dust model (also herein, NMME-DREAM) was modified to simulate spore emission, transport and deposition. Inexact knowledge of where cocci-causing fungus grows, the low resolution of cocci surveillance and an overall active period for significant dust events complicate analysis of the effect of the 5 July 2011 storm. In the larger context of monthly to annual disease surveillance, valley fever statistics, when compared against PM10 observation networks and modeled airborne dust concentrations, may reveal a likely cause and effect. Details provided by models and satellites fill time and space voids in conventional approaches to air quality and disease surveillance, leading to land-atmosphere modeling and remote sensing that clearly mark a path to advance valley fever epidemiology, surveillance and risk avoidance.

  7. Rift Valley Fever Risk Map Model and Seroprevalence in Selected Wild Ungulates and Camels from Kenya

    NARCIS (Netherlands)

    Britch, S.C.; Binepal, Y.S.; Ruder, M.G.; Kariithi, H.M.; Linthicum, K.J.; Anyamba, A.; Small, J.L.; Tucker, C.J.; Ateya, L.O.; Oriko, A.A.; Gacheru, S.; Wilson, W.C.

    2013-01-01

    Since the first isolation of Rift Valley fever virus (RVFV) in the 1930s, there have been multiple epizootics and epidemics in animals and humans in sub-Saharan Africa. Prospective climate-based models have recently been developed that flag areas at risk of RVFV transmission in endemic regions based

  8. Rift Valley Fever Virus Growth Curve Kinetics in Cattle and Sheep Peripheral Blood Monocyte Derived Macrophages

    Science.gov (United States)

    Rift Valley fever virus (RVFV), is a mosquito-borne, zoonotic pathogen within genus Phlebovirus, family Bunyaviridae that typically causes outbreaks in sub-Saharan Africa and recently spread to the Arabian Peninsula. In ruminants, RVFV infections cause mass abortion and high mortality rates in neona...

  9. Spatial distribution of non-clinical Rift Valley fever viral activity in ...

    African Journals Online (AJOL)

    Rift Valley fever (RVF) is an acute zoonotic viral disease of domestic ruminants in mainland Africa and Madagascar. The disease may exist in non-clinical form in apparently health animals. This study was designed to investigate the existence and spatial distribution of non-clinical form of RVF virus (RVFV) activity in wild and ...

  10. Four-segmented Rift Valley fever virus induces sterile immunity in sheep after a single vaccination

    NARCIS (Netherlands)

    Wichgers Schreur, P.J.; Kant-Eenbergen, H.C.M.; Keulen, van L.J.M.; Moormann, R.J.M.; Kortekaas, J.A.

    2015-01-01

    Rift Valley fever virus (RVFV), a mosquito-borne virus in the Bunyaviridae family, causes recurrent outbreaks with severe disease in ruminants and occasionally humans. The virus comprises a segmented genome consisting of a small (S), medium (M) and large (L) RNA segment of negative polarity. The

  11. Pathology Review of Two New Rift Valley Fever Virus Ruminant Models

    Science.gov (United States)

    Rift Valley fever virus (RVFV), is a mosquito-borne, zoonotic pathogen within genus Phlebovirus, family Bunyaviridae that typically causes outbreaks in sub-Saharan Africa and recently spread to the Arabian Peninsula. In ruminants, RVFV infections cause mass abortion and high mortality rates in neona...

  12. Sero-surveillance of Rift Valley fever in sheep and goat flocks in ...

    African Journals Online (AJOL)

    The surveillance of Rift Valley Fever (RVF) was carried out in the risk areas of Kenya by monitoring free range/migratory and sedentary farm sheep and goat herds for antibodies to RVF virus (RVFV). A total of 986 serum samples were collected and analyzed from farms in Molo, (where no outbreaks has ever been previously ...

  13. Climate Influence on Emerging Risk Areas for Rift Valley Fever Epidemics in Tanzania.

    Science.gov (United States)

    Mweya, Clement N; Mboera, Leonard E G; Kimera, Sharadhuli I

    2017-07-01

    Rift Valley Fever (RVF) is a climate-related arboviral infection of animals and humans. Climate is thought to represent a threat toward emerging risk areas for RVF epidemics globally. The objective of this study was to evaluate influence of climate on distribution of suitable breeding habitats for Culex pipiens complex, potential mosquito vector responsible for transmission and distribution of disease epidemics risk areas in Tanzania. We used ecological niche models to estimate potential distribution of disease risk areas based on vectors and disease co-occurrence data approach. Climatic variables for the current and future scenarios were used as model inputs. Changes in mosquito vectors' habitat suitability in relation to disease risk areas were estimated. We used partial receiver operating characteristic and the area under the curves approach to evaluate model predictive performance and significance. Habitat suitability for Cx. pipiens complex indicated broad-scale potential for change and shift in the distribution of the vectors and disease for both 2020 and 2050 climatic scenarios. Risk areas indicated more intensification in the areas surrounding Lake Victoria and northeastern part of the country through 2050 climate scenario. Models show higher probability of emerging risk areas spreading toward the western parts of Tanzania from northeastern areas and decrease in the southern part of the country. Results presented here identified sites for consideration to guide surveillance and control interventions to reduce risk of RVF disease epidemics in Tanzania. A collaborative approach is recommended to develop and adapt climate-related disease control and prevention strategies.

  14. A systematic review of Rift Valley Fever epidemiology 1931–2014

    Directory of Open Access Journals (Sweden)

    Mark O. Nanyingi

    2015-07-01

    Full Text Available Background: Rift Valley Fever (RVF is a mosquito-borne viral zoonosis that was first isolated and characterized in 1931 in Kenya. RVF outbreaks have resulted in significant losses through human illness and deaths, high livestock abortions and deaths. This report provides an overview on epidemiology of RVF including ecology, molecular diversity spatiotemporal analysis, and predictive risk modeling. Methodology: Using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA guidelines, we systematically searched for relevant RVF publications in repositories of the World Health Organization Library and Information Networks for Knowledge (WHOLIS, U.S Centers for Disease Control and Prevention (CDC, and Food and Agricultural Organization (FAO. Detailed searches were performed in Google Scholar, SpringerLink, and PubMed databases and included conference proceedings and books published from 1931 up to 31st January 2015. Results and discussion: A total of 84 studies were included in this review; majority (50% reported on common human and animal risk factors that included consumption of animal products, contact with infected animals and residing in low altitude areas associated with favorable climatic and ecological conditions for vector emergence. A total of 14 (16% of the publications described RVF progressive spatial and temporal distribution and the use of risk modeling for timely prediction of imminent outbreaks. Using distribution maps, we illustrated the gradual spread and geographical extent of disease; we also estimated the disease burden using aggregate human mortalities and cumulative outbreak periods for endemic regions. Conclusion: This review outlines common risk factors for RVF infections over wider geographical areas; it also emphasizes the role of spatial models in predicting RVF enzootics. It, therefore, explains RVF epidemiological status that may be used for design of targeted surveillance and control programs in

  15. A systematic review of Rift Valley Fever epidemiology 1931–2014

    Science.gov (United States)

    Nanyingi, Mark O.; Munyua, Peninah; Kiama, Stephen G.; Muchemi, Gerald M.; Thumbi, Samuel M.; Bitek, Austine O.; Bett, Bernard; Muriithi, Reese M.; Njenga, M. Kariuki

    2015-01-01

    Background Rift Valley Fever (RVF) is a mosquito-borne viral zoonosis that was first isolated and characterized in 1931 in Kenya. RVF outbreaks have resulted in significant losses through human illness and deaths, high livestock abortions and deaths. This report provides an overview on epidemiology of RVF including ecology, molecular diversity spatiotemporal analysis, and predictive risk modeling. Methodology Using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, we systematically searched for relevant RVF publications in repositories of the World Health Organization Library and Information Networks for Knowledge (WHOLIS), U.S Centers for Disease Control and Prevention (CDC), and Food and Agricultural Organization (FAO). Detailed searches were performed in Google Scholar, SpringerLink, and PubMed databases and included conference proceedings and books published from 1931 up to 31st January 2015. Results and discussion A total of 84 studies were included in this review; majority (50%) reported on common human and animal risk factors that included consumption of animal products, contact with infected animals and residing in low altitude areas associated with favorable climatic and ecological conditions for vector emergence. A total of 14 (16%) of the publications described RVF progressive spatial and temporal distribution and the use of risk modeling for timely prediction of imminent outbreaks. Using distribution maps, we illustrated the gradual spread and geographical extent of disease; we also estimated the disease burden using aggregate human mortalities and cumulative outbreak periods for endemic regions. Conclusion This review outlines common risk factors for RVF infections over wider geographical areas; it also emphasizes the role of spatial models in predicting RVF enzootics. It, therefore, explains RVF epidemiological status that may be used for design of targeted surveillance and control programs in endemic

  16. A systematic review of Rift Valley Fever epidemiology 1931-2014.

    Science.gov (United States)

    Nanyingi, Mark O; Munyua, Peninah; Kiama, Stephen G; Muchemi, Gerald M; Thumbi, Samuel M; Bitek, Austine O; Bett, Bernard; Muriithi, Reese M; Njenga, M Kariuki

    2015-01-01

    Rift Valley Fever (RVF) is a mosquito-borne viral zoonosis that was first isolated and characterized in 1931 in Kenya. RVF outbreaks have resulted in significant losses through human illness and deaths, high livestock abortions and deaths. This report provides an overview on epidemiology of RVF including ecology, molecular diversity spatiotemporal analysis, and predictive risk modeling. Using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, we systematically searched for relevant RVF publications in repositories of the World Health Organization Library and Information Networks for Knowledge (WHOLIS), U.S Centers for Disease Control and Prevention (CDC), and Food and Agricultural Organization (FAO). Detailed searches were performed in Google Scholar, SpringerLink, and PubMed databases and included conference proceedings and books published from 1931 up to 31st January 2015. A total of 84 studies were included in this review; majority (50%) reported on common human and animal risk factors that included consumption of animal products, contact with infected animals and residing in low altitude areas associated with favorable climatic and ecological conditions for vector emergence. A total of 14 (16%) of the publications described RVF progressive spatial and temporal distribution and the use of risk modeling for timely prediction of imminent outbreaks. Using distribution maps, we illustrated the gradual spread and geographical extent of disease; we also estimated the disease burden using aggregate human mortalities and cumulative outbreak periods for endemic regions. This review outlines common risk factors for RVF infections over wider geographical areas; it also emphasizes the role of spatial models in predicting RVF enzootics. It, therefore, explains RVF epidemiological status that may be used for design of targeted surveillance and control programs in endemic countries.

  17. A Hierarchical Network Approach for Modeling Rift Valley Fever Epidemics with Applications in North America: e62049

    National Research Council Canada - National Science Library

    Ling Xue; Lee W Cohnstaedt; H Morgan Scott; Caterina Scoglio

    2013-01-01

    .... In the event Rift Valley fever virus is introduced to the United States or other non-endemic areas, understanding the potential patterns of spread and the areas at risk based on disease vectors...

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

    Science.gov (United States)

    Amraoui, Fadila; Krida, Ghazi; Bouattour, Ali; Rhim, Adel; Daaboub, Jabeur; Harrat, Zoubir; Boubidi, Said-Chawki; Tijane, Mhamed; Sarih, Mhammed; Failloux, Anna-Bella

    2012-01-01

    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.

  19. 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.

  20. Protection of sheep against Rift Valley fever virus and sheep poxvirus with a recombinant capripoxvirus vaccine.

    Science.gov (United States)

    Soi, Reuben K; Rurangirwa, Fred R; McGuire, Travis C; Rwambo, Paul M; DeMartini, James C; Crawford, Timothy B

    2010-12-01

    Rift Valley fever (RVF) is an epizootic viral disease of sheep that can be transmitted from sheep to humans, particularly by contact with aborted fetuses. A capripoxvirus (CPV) recombinant virus (rKS1/RVFV) was developed, which expressed the Rift Valley fever virus (RVFV) Gn and Gc glycoproteins. These expressed glycoproteins had the correct size and reacted with monoclonal antibodies (MAb) to native glycoproteins. Mice vaccinated with rKS1/RVFV were protected against RVFV challenge. Sheep vaccinated with rKS1/RVFV twice developed neutralizing antibodies and were significantly protected against RVFV and sheep poxvirus challenge. These findings further document the value of CPV recombinants as ruminant vaccine vectors and support the inclusion of RVFV genes encoding glycoproteins in multivalent recombinant vaccines to be used where RVF occurs.

  1. Protection of Sheep against Rift Valley Fever Virus and Sheep Poxvirus with a Recombinant Capripoxvirus Vaccine▿

    Science.gov (United States)

    Soi, Reuben K.; Rurangirwa, Fred R.; McGuire, Travis C.; Rwambo, Paul M.; DeMartini, James C.; Crawford, Timothy B.

    2010-01-01

    Rift Valley fever (RVF) is an epizootic viral disease of sheep that can be transmitted from sheep to humans, particularly by contact with aborted fetuses. A capripoxvirus (CPV) recombinant virus (rKS1/RVFV) was developed, which expressed the Rift Valley fever virus (RVFV) Gn and Gc glycoproteins. These expressed glycoproteins had the correct size and reacted with monoclonal antibodies (MAb) to native glycoproteins. Mice vaccinated with rKS1/RVFV were protected against RVFV challenge. Sheep vaccinated with rKS1/RVFV twice developed neutralizing antibodies and were significantly protected against RVFV and sheep poxvirus challenge. These findings further document the value of CPV recombinants as ruminant vaccine vectors and support the inclusion of RVFV genes encoding glycoproteins in multivalent recombinant vaccines to be used where RVF occurs. PMID:20876822

  2. Serological surveillance studies confirm the Rift Valley fever virus free status in South Korea.

    Science.gov (United States)

    Kim, Hyun Joo; Park, Jee-Yong; Jeoung, Hye-Young; Yeh, Jung-Yong; Cho, Yun-Sang; Choi, Jeong-Soo; Lee, Ji-Youn; Cho, In-Soo; Yoo, Han-Sang

    2015-10-01

    Rift Valley fever is a mosquito-borne zoonotic disease of domestic ruminants. This disease causes abortions in pregnant animals, and it has a high mortality rate in newborn animals. Recently, a Rift Valley fever virus (RVFV) outbreak in the Arabian Peninsula increased its potential spread to new regions worldwide. In non-endemic or disease-free countries, early detection and surveillance are important for preventing the introduction of RVFV. In this study, a serological surveillance was conducted to detect antibodies against RVFV. A total of 2382 serum samples from goats and cattle were randomly collected from nine areas in South Korea from 2011 to 2013. These samples were tested for antibodies against RVFV, using commercial ELISA kits. None of the goats and cattle were positive for antibodies against RVFV. This finding suggests that this disease is not present in South Korea, and furthermore presents the evidence of the RVFV-free status of this country.

  3. Seroprevalence of Sheep and Goat Pox, Peste Des Petits Ruminants and Rift Valley Fever in Saudi Arabia

    OpenAIRE

    Hani Boshra; Thang Truong; Shawn Babiuk; Maged Gomaa Hemida

    2015-01-01

    Sheep and goat pox, peste des petits ruminants and Rift Valley fever are important diseases of small ruminant livestock. Sheep and goat pox, along with peste des petits ruminants, are endemic throughout most of Africa, Asia and the Middle East. Whereas Rift Valley fever is endemic in Africa, outbreaks in the Middle East have been reported over the past decade, including the Arabian Peninsula. Saudi Arabia is a major importer of livestock, and understanding the prevalence of these viral infect...

  4. Statistical modeling of the abundance of vectors of West African Rift Valley fever in Barkedji, Senegal.

    Directory of Open Access Journals (Sweden)

    Cheikh Talla

    Full Text Available Rift Valley fever is an emerging mosquito-borne disease that represents a threat to human and animal health. The exophilic and exophagic behavior of the two main vector in West Africa (Aedes vexans and Culex poicilipes, adverse events post-vaccination, and lack of treatment, render ineffective the disease control. Therefore it is essential to develop an information system that facilitates decision-making and the implementation of adaptation strategies. In East Africa, RVF outbreaks are linked with abnormally high rainfall, and can be predicted up to 5 months in advance by modeling approaches using climatic and environmental parameters. However, the application of these models in West Africa remains unsatisfactory due to a lack of data for animal and human cases and differences in the dynamics of the disease emergence and the vector species involved in transmission. Models have been proposed for West Africa but they were restricted to rainfall impact analysis without a spatial dimension. In this study, we developed a mixed Bayesian statistical model to evaluate the effects of climatic and ecological determinants on the spatiotemporal dynamics of the two main vectors. Adult mosquito abundance data were generated from July to December every fortnight in 2005-2006 at 79 sites, including temporary ponds, bare soils, shrubby savannah, wooded savannah, steppes, and villages in the Barkédji area. The results demonstrate the importance of environmental factors and weather conditions for predicting mosquito abundance. The rainfall and minimum temperature were positively correlated with the abundance of Cx. poicilipes, whereas the maximum temperature had negative effects. The rainfall was negatively correlated with the abundance of Ae. vexans. After combining land cover classes, weather conditions, and vector abundance, our model was used to predict the areas and periods with the highest risks of vector pressure. This information could support decision

  5. Characterization of Rift Valley fever virus MP-12 strain encoding NSs of Punta Toro virus or sandfly fever Sicilian virus.

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    Olga A Lihoradova

    Full Text Available Rift Valley fever virus (RVFV; genus Phlebovirus, family Bunyaviridae is a mosquito-borne zoonotic pathogen which can cause hemorrhagic fever, neurological disorders or blindness in humans, and a high rate of abortion in ruminants. MP-12 strain, a live-attenuated candidate vaccine, is attenuated in the M- and L-segments, but the S-segment retains the virulent phenotype. MP-12 was manufactured as an Investigational New Drug vaccine by using MRC-5 cells and encodes a functional NSs gene, the major virulence factor of RVFV which 1 induces a shutoff of the host transcription, 2 inhibits interferon (IFN-β promoter activation, and 3 promotes the degradation of dsRNA-dependent protein kinase (PKR. MP-12 lacks a marker for differentiation of infected from vaccinated animals (DIVA. Although MP-12 lacking NSs works for DIVA, it does not replicate efficiently in type-I IFN-competent MRC-5 cells, while the use of type-I IFN-incompetent cells may negatively affect its genetic stability. To generate modified MP-12 vaccine candidates encoding a DIVA marker, while still replicating efficiently in MRC-5 cells, we generated recombinant MP-12 encoding Punta Toro virus Adames strain NSs (rMP12-PTNSs or Sandfly fever Sicilian virus NSs (rMP12-SFSNSs in place of MP-12 NSs. We have demonstrated that those recombinant MP-12 viruses inhibit IFN-β mRNA synthesis, yet do not promote the degradation of PKR. The rMP12-PTNSs, but not rMP12-SFSNSs, replicated more efficiently than recombinant MP-12 lacking NSs in MRC-5 cells. Mice vaccinated with rMP12-PTNSs or rMP12-SFSNSs induced neutralizing antibodies at a level equivalent to those vaccinated with MP-12, and were efficiently protected from wild-type RVFV challenge. The rMP12-PTNSs and rMP12-SFSNSs did not induce antibodies cross-reactive to anti-RVFV NSs antibody and are therefore applicable to DIVA. Thus, rMP12-PTNSs is highly efficacious, replicates efficiently in MRC-5 cells, and encodes a DIVA marker, all of which

  6. Estimating sources of Valley Fever pathogen propagation in southern Arizona: A remote sensing approach

    Science.gov (United States)

    Pianalto, Frederick S.

    Coccidioidomycosis (Valley Fever) is an environmentally-mediated respiratory disease caused by the inhalation of airborne spores from the fungi Coccidioides spp. The fungi reside in arid and semi-arid soils of the Americas. The disease has increased epidemically in Arizona and other areas within the last two decades. Despite this increase, the ecology of the fungi remains obscure, and environmental antecedents of the disease are largely unstudied. Two sources of soil disturbance, hypothesized to affect soil ecology and initiate spore dissemination, are investigated. Nocturnal desert rodents interact substantially with the soil substrate. Rodents are hypothesized to act as a reservoir of coccidioidomycosis, a mediator of soil properties, and a disseminator of fungal spores. Rodent distributions are poorly mapped for the study area. We build automated multi-linear regression models and decision tree models for ten rodent species using rodent trapping data from the Organ Pipe Cactus National Monument (ORPI) in southwest Arizona with a combination of surface temperature, a vegetation index and its texture, and a suite of topographic rasters. Surface temperature, derived from Landsat TM thermal images, is the most widely selected predictive variable in both automated methods. Construction-related soil disturbance (e.g. road construction, trenching, land stripping, and earthmoving) is a significant source of fugitive dust, which decreases air quality and may carry soil pathogens. Annual differencing of Landsat Thematic Mapper (TM) mid-infrared images is used to create change images, and thresholded change areas are associated with coordinates of local dust inspections. The output metric identifies source areas of soil disturbance, and it estimates the annual amount of dust-producing surface area for eastern Pima County spanning 1994 through 2009. Spatially explicit construction-related soil disturbance and rodent abundance data are compared with coccidioidomycosis

  7. The Rift Valley Fever virus protein NSm and putative cellular protein interactions

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    Engdahl Cecilia

    2012-07-01

    Full Text Available Abstract Rift Valley Fever is an infectious viral disease and an emerging problem in many countries of Africa and on the Arabian Peninsula. The causative virus is predominantly transmitted by mosquitoes and high mortality and abortion rates characterize outbreaks in animals while symptoms ranging from mild to life-threatening encephalitis and hemorrhagic fever are noticed among infected humans. For a better prevention and treatment of the infection, an increased knowledge of the infectious process of the virus is required. The focus of this work was to identify protein-protein interactions between the non-structural protein (NSm, encoded by the M-segment of the virus, and host cell proteins. This study was initiated by screening approximately 26 million cDNA clones of a mouse embryonic cDNA library for interactions with the NSm protein using a yeast two-hybrid system. We have identified nine murine proteins that interact with NSm protein of Rift Valley Fever virus, and the putative protein-protein interactions were confirmed by growth selection procedures and β-gal activity measurements. Our results suggest that the cleavage and polyadenylation specificity factor subunit 2 (Cpsf2, the peptidyl-prolyl cis-trans isomerase (cyclophilin-like 2 protein (Ppil2, and the synaptosome-associated protein of 25 kDa (SNAP-25 are the most promising targets for the NSm protein of the virus during an infection.

  8. Potential for Mosquitoes (Diptera: Culicidae) From Florida to Transmit Rift Valley Fever Virus

    Science.gov (United States)

    2013-09-01

    suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway...www.cdc.gov/EID/content/13/8/e1.htm). Britch, S.C.,K. J.Linthicum,A.Anyamba,C. J.Tucker,E.W. Pak, F. A. Maloney, K. Cobb, E. Stanwix, J. Humphries , A...Valley fever virus. J. Am. Mosq. Control Assoc. 24: 502Ð507. Turell, M. J., K. J. Linthicum, L. A. Patrican, F. G. Davies , A. Kairo, and C. L. Bailey

  9. A Haploid Genetic Screen Identifies Heparan Sulfate Proteoglycans Supporting Rift Valley Fever Virus Infection.

    Science.gov (United States)

    Riblett, Amber M; Blomen, Vincent A; Jae, Lucas T; Altamura, Louis A; Doms, Robert W; Brummelkamp, Thijn R; Wojcechowskyj, Jason A

    2015-11-18

    Rift Valley fever virus (RVFV) causes recurrent insect-borne epizootics throughout the African continent, and infection of humans can lead to a lethal hemorrhagic fever syndrome. Deep mutagenesis of haploid human cells was used to identify host factors required for RVFV infection. This screen identified a suite of enzymes involved in glycosaminoglycan (GAG) biogenesis and transport, including several components of the cis-oligomeric Golgi (COG) complex, one of the central components of Golgi complex trafficking. In addition, disruption of PTAR1 led to RVFV resistance as well as reduced heparan sulfate surface levels, consistent with recent observations that PTAR1-deficient cells exhibit altered Golgi complex morphology and glycosylation defects. A variety of biochemical and genetic approaches were utilized to show that both pathogenic and attenuated RVFV strains require GAGs for efficient infection on some, but not all, cell types, with the block to infection being at the level of virion attachment. Examination of other members of the Bunyaviridae family for GAG-dependent infection suggested that the interaction with GAGs is not universal among bunyaviruses, indicating that these viruses, as well as RVFV on certain cell types, employ additional unidentified virion attachment factors and/or receptors. Rift Valley fever virus (RVFV) is an emerging pathogen that can cause severe disease in humans and animals. Epizootics among livestock populations lead to high mortality rates and can be economically devastating. Human epidemics of Rift Valley fever, often initiated by contact with infected animals, are characterized by a febrile disease that sometimes leads to encephalitis or hemorrhagic fever. The global burden of the pathogen is increasing because it has recently disseminated beyond Africa, which is of particular concern because the virus can be transmitted by widely distributed mosquito species. There are no FDA-licensed vaccines or antiviral agents with activity

  10. Seroprevalence of Sheep and Goat Pox, Peste Des Petits Ruminants and Rift Valley Fever in Saudi Arabia.

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    Hani Boshra

    Full Text Available Sheep and goat pox, peste des petits ruminants and Rift Valley fever are important diseases of small ruminant livestock. Sheep and goat pox, along with peste des petits ruminants, are endemic throughout most of Africa, Asia and the Middle East. Whereas Rift Valley fever is endemic in Africa, outbreaks in the Middle East have been reported over the past decade, including the Arabian Peninsula. Saudi Arabia is a major importer of livestock, and understanding the prevalence of these viral infections would be useful for disease control. In this study, sera from sheep and goats were collected from 3 regions in Saudi Arabia. They were evaluated for antibodies specific to sheep and goat pox, peste des petits ruminants and Rift Valley fever by virus neutralization assays. To the best of our knowledge, this is the first study to evaluate the seroprevalence of these viruses in sheep and goats.

  11. Seroprevalence of Sheep and Goat Pox, Peste Des Petits Ruminants and Rift Valley Fever in Saudi Arabia.

    Science.gov (United States)

    Boshra, Hani; Truong, Thang; Babiuk, Shawn; Hemida, Maged Gomaa

    2015-01-01

    Sheep and goat pox, peste des petits ruminants and Rift Valley fever are important diseases of small ruminant livestock. Sheep and goat pox, along with peste des petits ruminants, are endemic throughout most of Africa, Asia and the Middle East. Whereas Rift Valley fever is endemic in Africa, outbreaks in the Middle East have been reported over the past decade, including the Arabian Peninsula. Saudi Arabia is a major importer of livestock, and understanding the prevalence of these viral infections would be useful for disease control. In this study, sera from sheep and goats were collected from 3 regions in Saudi Arabia. They were evaluated for antibodies specific to sheep and goat pox, peste des petits ruminants and Rift Valley fever by virus neutralization assays. To the best of our knowledge, this is the first study to evaluate the seroprevalence of these viruses in sheep and goats.

  12. Intensified dust storm activity and Valley fever infection in the southwestern United States

    Science.gov (United States)

    Tong, Daniel Q.; Wang, Julian X. L.; Gill, Thomas E.; Lei, Hang; Wang, Binyu

    2017-05-01

    Climate models have consistently projected a drying trend in the southwestern United States, aiding speculation of increasing dust storms in this region. Long-term climatology is essential to documenting the dust trend and its response to climate variability. We have reconstructed long-term dust climatology in the western United States, based on a comprehensive dust identification method and continuous aerosol observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. We report here direct evidence of rapid intensification of dust storm activity over American deserts in the past decades (1988-2011), in contrast to reported decreasing trends in Asia and Africa. The frequency of windblown dust storms has increased 240% from 1990s to 2000s. This dust trend is associated with large-scale variations of sea surface temperature in the Pacific Ocean, with the strongest correlation with the Pacific Decadal Oscillation. We further investigate the relationship between dust and Valley fever, a fast-rising infectious disease caused by inhaling soil-dwelling fungus (Coccidioides immitis and C. posadasii) in the southwestern United States. The frequency of dust storms is found to be correlated with Valley fever incidences, with a coefficient (r) comparable to or stronger than that with other factors believed to control the disease in two endemic centers (Maricopa and Pima County, Arizona).

  13. Serological evidence for the circulation of Rift Valley Fever Virus in domestic small ruminants in Southern Gabon

    OpenAIRE

    Maganga, G. D.; Ndong, A. L. A.; Okouyi, C. S. M.; Mandanda, S. M.; N'Dilimabaka, N.; Pinto, A.; Agossou, E.; Cossic, B.; Akue, J. P.; Leroy, Eric

    2017-01-01

    Rift Valley fever (RVF) is a zoonotic disease, which caused several epidemics in humans in many countries of Africa. Using an inhibition enzyme-linked immunosorbent assay (ELISA), real-time reverse transcription PCR, and nested one-step reverse transcription PCR, we conducted a cross-sectional study in populations of sheep and goats from the Mongo County in 2014 to determine the circulation of the Rift Valley fever virus (RVFV) in small ruminants from this area. From a total of 201 small rumi...

  14. Haemorrhagic Fevers, Viral

    Science.gov (United States)

    ... is usually applied to disease caused by Arenaviridae (Lassa fever, Junin and Machupo), Bunyaviridae (Crimean-Congo haemorrhagic ... fever Dengue and severe dengue Ebola virus disease Lassa fever Marburg haemorrhagic fever Rift Valley fever Multimedia, ...

  15. Broad spectrum antiviral activity of favipiravir (T-705: protection from highly lethal inhalational Rift Valley Fever.

    Directory of Open Access Journals (Sweden)

    Amy L Caroline

    2014-04-01

    Full Text Available BACKGROUND: Development of antiviral drugs that have broad-spectrum activity against a number of viral infections would be of significant benefit. Due to the evolution of resistance to currently licensed antiviral drugs, development of novel anti-influenza drugs is in progress, including Favipiravir (T-705, which is currently in human clinical trials. T-705 displays broad-spectrum in vitro activity against a number of viruses, including Rift Valley Fever virus (RVFV. RVF is an important neglected tropical disease that causes human, agricultural, and economic losses in endemic regions. RVF has the capacity to emerge in new locations and also presents a potential bioterrorism threat. In the current study, the in vivo efficacy of T-705 was evaluated in Wistar-Furth rats infected with the virulent ZH501 strain of RVFV by the aerosol route. METHODOLOGY/PRINCIPAL FINDINGS: Wistar-Furth rats are highly susceptible to a rapidly lethal disease after parenteral or inhalational exposure to the pathogenic ZH501 strain of RVFV. In the current study, two experiments were performed: a dose-determination study and a delayed-treatment study. In both experiments, all untreated control rats succumbed to disease. Out of 72 total rats infected with RVFV and treated with T-705, only 6 succumbed to disease. The remaining 66 rats (92% survived lethal infection with no significant weight loss or fever. The 6 treated rats that succumbed survived significantly longer before succumbing to encephalitic disease. CONCLUSIONS/SIGNIFICANCE: Currently, there are no licensed antiviral drugs for treating RVF. Here, T-705 showed remarkable efficacy in a highly lethal rat model of Rift Valley Fever, even when given up to 48 hours post-infection. This is the first study to show protection of rats infected with the pathogenic ZH501 strain of RVFV. Our data suggest that T-705 has potential to be a broad-spectrum antiviral drug.

  16. Seroprevalence of Rift Valley fever virus in sheep and goats in Zambézia, Mozambique

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    Anne-Lie Blomström

    2016-07-01

    Full Text Available Background: The Rift Valley fever virus (RVFV is a vector-borne virus that causes disease in ruminants, but it can also infect humans. In humans, the infection can be asymptomatic but can also lead to illness, ranging from a mild disease with fever, headache and muscle pain to a severe disease with encephalitis and haemorrhagic fever. In rare cases, death can occur. In infected animals, influenza-like symptoms can occur, and abortion and mortality in young animals are indicative of RVFV infection. Since the initial outbreak in Kenya in the 1930s, the virus has become endemic to most of sub-Saharan Africa. In 2000, the virus appeared in Yemen and Saudi Arabia; this was the first outbreak of RVF outside of Africa. Rift Valley fever epidemics are often connected to heavy rainfall, leading to an increased vector population and spread of the virus to animals and/or humans. However, the virus needs to be maintained during the inter-epidemic periods. In this study, we investigated the circulation of RVFV in small ruminants (goats and sheep in Zambézia, Mozambique, an area with a close vector/wildlife/livestock/human interface. Materials and methods: Between September and October 2013, 181 sheep and 187 goat blood samples were collected from eight localities in the central region of Zambézia, Mozambique. The samples were analysed for the presence of antibodies against RVFV using a commercial competitive ELISA. Results and discussion: The overall seroprevalence was higher in sheep (44.2% than goats (25.1%; however, there was a high variation in seroprevalence between different localities. The data indicate an increased seroprevalence for sheep compared to 2010, when a similar study was conducted in this region and in overlapping villages. No noticeable health problems in the herds were reported. Conclusions: This study shows an inter-epidemic circulation of RVFV in small ruminants in Zambézia, Mozambique. Neither outbreaks of RVF nor typical clinical

  17. Bead-based suspension array for simultaneous detection of antibodies against the Rift Valley fever virus nucleocapsid and Gn glycoprotein

    NARCIS (Netherlands)

    Wal, van der F.J.; Achterberg, R.P.; Boer, de S.M.; Boshra, H.; Brun, A.; Maassen, C.B.M.; Kortekaas, J.A.

    2012-01-01

    A multiplex bead-based suspension array was developed that can be used for the simultaneous detection of antibodies against the surface glycoprotein Gn and the nucleocapsid protein N of Rift Valley fever virus (RVFV) in various animal species. The N protein and the purified ectodomain of the Gn

  18. Sorafenib impedes Rift Valley fever virus egress by inhibiting Valosin containing protein function in the cellular secretory pathway

    Science.gov (United States)

    2017-08-09

    arboviral zoonosis that can cause 56 severe disease in humans and livestock. In ruminants, the disease is characterized by 57 spontaneous abortion rate...Molecule FISH Reveals Non- selective 433 Packaging of Rift Valley Fever Virus Genome Segments. PLoS Pathog 12. 434 TR-17-166 Distribution Statement

  19. Serologic evidence of exposure to Rift Valley fever virus detected in Tunisia

    Directory of Open Access Journals (Sweden)

    A. Bosworth

    2016-01-01

    Full Text Available Rift Valley fever virus (RVFv is capable of causing dramatic outbreaks amongst economically important animal species and is capable of causing severe symptoms and mortality in humans. RVFv is known to circulate widely throughout East Africa; serologic evidence of exposure has also been found in some northern African countries, including Mauritania. This study aimed to ascertain whether RVFv is circulating in regions beyond its known geographic range. Samples from febrile patients (n=181 and nonfebrile healthy agricultural and slaughterhouse workers (n=38 were collected during the summer of 2014 and surveyed for exposure to RVFv by both serologic tests and PCR. Of the 219 samples tested, 7.8% of nonfebrile participants showed immunoglobulin G reactivity to RVFv nucleoprotein and 8.3% of febrile patients showed immunoglobulin M reactivity, with the latter samples indicating recent exposure to the virus. Our results suggest an active circulation of RVFv and evidence of human exposure in the population of Tunisia.

  20. Repurposing FDA-approved drugs as therapeutics to treat Rift Valley fever virus infection

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    Ashwini eBenedict

    2015-07-01

    Full Text Available There are currently no FDA-approved therapeutics available to treat Rift Valley fever virus (RVFV infection. In an effort to repurpose drugs for RVFV treatment, a library of FDA-approved drugs was screened to determine their ability to inhibit RVFV. Several drugs from varying compound classes, including inhibitors of growth factor receptors, microtubule assembly/disassembly, and DNA synthesis, were found to reduce RVFV replication. The hepatocellular and renal cell carcinoma drug, sorafenib, was the most effective inhibitor, being non-toxic and demonstrating inhibition of RVFV in a cell-type and virus strain independent manner. Mechanism of action studies indicated that sorafenib targets at least two stages in the virus infectious cycle, RNA synthesis and viral egress. Computational modeling studies also support this conclusion. siRNA knockdown of Raf proteins indicated that non-classical targets of sorafenib are likely important for the replication of RVFV.

  1. Ultrastructural study of Rift Valley fever virus in the mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Christopher; Steele, Keith E.; Honko, Anna; Shamblin, Joshua; Hensley, Lisa E. [United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, MD (United States); Smith, Darci R., E-mail: darci.smith1@us.army.mil [United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, MD (United States)

    2012-09-15

    Detailed ultrastructural studies of Rift Valley fever virus (RVFV) in the mouse model are needed to develop and characterize a small animal model of RVF for the evaluation of potential vaccines and therapeutics. In this study, the ultrastructural features of RVFV infection in the mouse model were analyzed. The main changes in the liver included the presence of viral particles in hepatocytes and hepatic stem cells accompanied by hepatocyte apoptosis. However, viral particles were observed rarely in the liver; in contrast, particles were extremely abundant in the CNS. Despite extensive lymphocytolysis, direct evidence of viral replication was not observed in the lymphoid tissue. These results correlate with the acute-onset hepatitis and delayed-onset encephalitis that are dominant features of severe human RVF, but suggest that host immune-mediated mechanisms contribute significantly to pathology. The results of this study expand our knowledge of RVFV-host interactions and further characterize the mouse model of RVF.

  2. A review of mosquitoes associated with Rift Valley fever virus in Madagascar.

    Science.gov (United States)

    Tantely, Luciano M; Boyer, Sébastien; Fontenille, Didier

    2015-04-01

    Rift Valley fever (RVF) is a viral zoonotic disease occurring throughout Africa, the Arabian Peninsula, and Madagascar. The disease is caused by a Phlebovirus (RVF virus [RVFV]) transmitted to vertebrate hosts through the bite of infected mosquitoes. In Madagascar, the first RVFV circulation was reported in 1979 based on detection in mosquitoes but without epidemic episode. Subsequently, two outbreaks occurred: the first along the east coast and in the central highlands in 1990 and 1991 and the most recent along the northern and eastern coasts and in the central highlands in 2008 and 2009. Despite the presence of 24 mosquitoes species potentially associated with RVFV transmission in Madagascar, little associated entomological information is available. In this review, we list the RVFV vector, Culex antennatus, as well as other taxa as candidate vector species. We discuss risk factors from an entomological perspective for the re-emergence of RVF in Madagascar. © The American Society of Tropical Medicine and Hygiene.

  3. Epidemiologic Investigations into Outbreaks of Rift Valley Fever in Humans, South Africa, 2008–2011

    Science.gov (United States)

    Thomas, Juno; Weyer, Jacqueline; Cengimbo, Ayanda; Landoh, Dadja E.; Jacobs, Charlene; Ntuli, Sindile; Modise, Motshabi; Mathonsi, Moshe; Mashishi, Morton S.; Leman, Patricia A.; le Roux, Chantel; Jansen van Vuren, Petrus; Kemp, Alan; Paweska, Janusz T.; Blumberg, Lucille

    2013-01-01

    Rift Valley fever (RVF) is an emerging zoonosis posing a public health threat to humans in Africa. During sporadic RVF outbreaks in 2008–2009 and widespread epidemics in 2010–2011, 302 laboratory-confirmed human infections, including 25 deaths (case-fatality rate, 8%) were identified. Incidence peaked in late summer to early autumn each year, which coincided with incidence rate patterns in livestock. Most case-patients were adults (median age 43 years), men (262; 87%), who worked in farming, animal health or meat-related industries (83%). Most case-patients reported direct contact with animal tissues, blood, or other body fluids before onset of illness (89%); mosquitoes likely played a limited role in transmission of disease to humans. Close partnership with animal health and agriculture sectors allowed early recognition of human cases and appropriate preventive health messaging. PMID:29360021

  4. Experimental Infection of Calves by Two Genetically-Distinct Strains of Rift Valley Fever Virus

    Directory of Open Access Journals (Sweden)

    William C. Wilson

    2016-05-01

    Full Text Available Recent outbreaks of Rift Valley fever in ruminant livestock, characterized by mass abortion and high mortality rates in neonates, have raised international interest in improving vaccine control strategies. Previously, we developed a reliable challenge model for sheep that improves the evaluation of existing and novel vaccines in sheep. This sheep model demonstrated differences in the pathogenesis of Rift Valley fever virus (RVFV infection between two genetically-distinct wild-type strains of the virus, Saudi Arabia 2001 (SA01 and Kenya 2006 (Ken06. Here, we evaluated the pathogenicity of these two RVFV strains in mixed breed beef calves. There was a transient increase in rectal temperatures with both virus strains, but this clinical sign was less consistent than previously reported with sheep. Three of the five Ken06-infected animals had an early-onset viremia, one day post-infection (dpi, with viremia lasting at least three days. The same number of SA01-infected animals developed viremia at 2 dpi, but it only persisted through 3 dpi in one animal. The average virus titer for the SA01-infected calves was 1.6 logs less than for the Ken06-infected calves. Calves, inoculated with either strain, seroconverted by 5 dpi and showed time-dependent increases in their virus-neutralizing antibody titers. Consistent with the results obtained in the previous sheep study, elevated liver enzyme levels, more severe liver pathology and higher virus titers occurred with the Ken06 strain as compared to the SA01 strain. These results demonstrate the establishment of a virulent challenge model for vaccine evaluation in calves.

  5. Postepidemic analysis of Rift Valley fever virus transmission in northeastern kenya: a village cohort study.

    Directory of Open Access Journals (Sweden)

    A Desirée LaBeaud

    2011-08-01

    Full Text Available In endemic areas, Rift Valley fever virus (RVFV is a significant threat to both human and animal health. Goals of this study were to measure human anti-RVFV seroprevalence in a high-risk area following the 2006-2007 Kenyan Rift Valley Fever (RVF epidemic, to identify risk factors for interval seroconversion, and to monitor individuals previously exposed to RVFV in order to document the persistence of their anti-RVFV antibodies.We conducted a village cohort study in Ijara District, Northeastern Province, Kenya. One hundred two individuals tested for RVFV exposure before the 2006-2007 RVF outbreak were restudied to determine interval anti-RVFV seroconversion and persistence of humoral immunity since 2006. Ninety-two additional subjects were enrolled from randomly selected households to help identify risk factors for current seropositivity. Overall, 44/194 or 23% (CI(95%:17%-29% of local residents were RVFV seropositive. 1/85 at-risk individuals restudied in the follow-up cohort had seroconverted since early 2006. 27/92 (29%, CI(95%: 20%-39% of newly tested individuals were seropositive. All 13 individuals with positive titers (by plaque reduction neutralization testing (PRNT₈₀ in 2006 remained positive in 2009. After adjustment in multivariable logistic models, age, village, and drinking raw milk were significantly associated with RVFV seropositivity. Visual impairment (defined as ≤ 20/80 was much more likely in the RVFV-seropositive group (P 1∶40 for more than 3 years. In concordance with previous studies, residents of the more rural village were more likely to be seropositive and RVFV seropositivity was associated with poor visual acuity. Raw milk consumption was strongly associated with RVFV exposure, which may represent an important new focus for public health education during future RVF outbreaks.

  6. Mapping Environmental Dimensions of Dengue Fever Transmission Risk in the Aburrá Valley, Colombia

    Science.gov (United States)

    Arboleda, Sair; Nicolas, Jaramillo-O.; Peterson, A. Townsend

    2009-01-01

    Dengue fever (DF) is endemic in Medellín, the second largest Colombian city, and surrounding municipalities. We used DF case and satellite environmental data to investigate conditions associated with suitable areas for DF occurrence in 2008 in three municipalities (Bello, Medellín and Itagüí). We develop spatially stratified tests of ecological niche models, and found generally good predictive ability, with all model tests yielding results significantly better than random expectations. We concluded that Bello and Medellín present ecological conditions somewhat different from, and more suitable for DF than, those of Itagüí. We suggest that areas predicted by our models as suitable for DF could be considered as at-risk, and could be used to guide campaigns for DF prevention in these municipalities. PMID:20049244

  7. The epidemiology and socio-economic impact of Rift Valley fever epidemics in Tanzania: A review

    Directory of Open Access Journals (Sweden)

    Calvin Sindato

    2012-06-01

    Full Text Available A review was conducted to provide comprehensive update on Rift Valley fever (RVF in Tanzania, with particular attention devoted to trend of occurrence, epidemiological factors, socio-economic impact and measures which were applied to its control. Information presented in this paper was obtained through extensive literature review. Rift Valley fever was documented for the first time in Tanzania in 1977. This was followed by epidemics in 1997 and 2007. Contrary to the latest epidemic in 2007 sporadic cases of RVF during the previous epidemics were confined to mainly livestock and mostly affecting northern parts of Tanzania. The latest disease epidemic expanded to cover wider areas (mostly northern and central zones of the country involving both human and domestic ruminants. During the latest disease outbreak 52.4% (n = 21 of regions in Tanzania mainland were affected and majority (72.7, n = 11 of the regions had concurrent infections in human and animals. Phylogenetic comparison of nucleotide and amimo acid sequences revealed different virus strains between Kenya and Tanzania.Epidemiological factors that were considered responsible for the previous RVF epidemics in Tanzania included farming systems, climatic factors, vector activities and presence of large population of ruminant species, animal movements and food consumption habits. Majority of the RVF positive cases in the latest epidemic were livestock under pastoral and agro-pastoral farming systems.The disease caused serious effects on rural people’s food security and household nutrition and on direct and indirect losses to livestock producers in the country. Psycho-social distress that communities went through was enormous, which involved the thinking about the loss of their family members and/or relatives, their livestock and crop production. Socially, the status of most livestock producers was eroded in their communities.Cessation of lucrative trade in ruminants resulted in serious

  8. Planning for Rift Valley fever virus: use of geographical information systems to estimate the human health threat of white-tailed deer (Odocoileus virginianus)-related transmission

    National Research Council Canada - National Science Library

    Kakani, Sravan; LaBeaud, A Desirée; King, Charles H

    2010-01-01

    Rift Valley fever (RVF) virus is a mosquito-borne phlebovirus of the Bunyaviridae family that causes frequent outbreaks of severe animal and human disease in sub-Saharan Africa, Egypt and the Arabian Peninsula...

  9. Valley fever: finding new places for an old disease: Coccidioides immitis found in Washington State soil associated with recent human infection

    National Research Council Canada - National Science Library

    Litvintseva, Anastasia P; Marsden-Haug, Nicola; Hurst, Steven; Hill, Heather; Gade, Lalitha; Driebe, Elizabeth M; Ralston, Cindy; Roe, Chandler; Barker, Bridget M; Goldoft, Marcia; Keim, Paul; Wohrle, Ron; Thompson, 3rd, George R; Engelthaler, David M; Brandt, Mary E; Chiller, Tom

    2015-01-01

    We used real-time polymerase chain reaction and culture to demonstrate persistent colonization of soils by Coccidioides immitis, an agent of valley fever, in Washington State linked to recent human...

  10. A network-based meta-population approach to model Rift Valley fever epidemics.

    Science.gov (United States)

    Xue, Ling; Scott, H Morgan; Cohnstaedt, Lee W; Scoglio, Caterina

    2012-08-07

    Rift Valley fever virus (RVFV) has been expanding its geographical distribution with important implications for both human and animal health. The emergence of Rift Valley fever (RVF) in the Middle East, and its continuing presence in many areas of Africa, has negatively impacted both medical and veterinary infrastructures and human morbidity, mortality, and economic endpoints. Furthermore, worldwide attention should be directed towards the broader infection dynamics of RVFV, because suitable host, vector and environmental conditions for additional epidemics likely exist on other continents; including Asia, Europe and the Americas. We propose a new compartmentalized model of RVF and the related ordinary differential equations to assess disease spread in both time and space; with the latter driven as a function of contact networks. Humans and livestock hosts and two species of vector mosquitoes are included in the model. The model is based on weighted contact networks, where nodes of the networks represent geographical regions and the weights represent the level of contact between regional pairings for each set of species. The inclusion of human, animal, and vector movements among regions is new to RVF modeling. The movement of the infected individuals is not only treated as a possibility, but also an actuality that can be incorporated into the model. We have tested, calibrated, and evaluated the model using data from the recent 2010 RVF outbreak in South Africa as a case study; mapping the epidemic spread within and among three South African provinces. An extensive set of simulation results shows the potential of the proposed approach for accurately modeling the RVF spreading process in additional regions of the world. The benefits of the proposed model are twofold: not only can the model differentiate the maximum number of infected individuals among different provinces, but also it can reproduce the different starting times of the outbreak in multiple locations

  11. RNA Interference Restricts Rift Valley Fever Virus in Multiple Insect Systems.

    Science.gov (United States)

    Dietrich, Isabelle; Jansen, Stephanie; Fall, Gamou; Lorenzen, Stephan; Rudolf, Martin; Huber, Katrin; Heitmann, Anna; Schicht, Sabine; Ndiaye, El Hadji; Watson, Mick; Castelli, Ilaria; Brennan, Benjamin; Elliott, Richard M; Diallo, Mawlouth; Sall, Amadou A; Failloux, Anna-Bella; Schnettler, Esther; Kohl, Alain; Becker, Stefanie C

    2017-01-01

    The emerging bunyavirus Rift Valley fever virus (RVFV) is transmitted to humans and livestock by a large number of mosquito species. RNA interference (RNAi) has been characterized as an important innate immune defense mechanism used by mosquitoes to limit replication of positive-sense RNA flaviviruses and togaviruses; however, little is known about its role against negative-strand RNA viruses such as RVFV. We show that virus-specific small RNAs are produced in infected mosquito cells, in Drosophila melanogaster cells, and, most importantly, also in RVFV vector mosquitoes. By addressing the production of small RNAs in adult Aedes sp. and Culex quinquefasciatus mosquitoes, we showed the presence of virus-derived Piwi-interacting RNAs (piRNAs) not only in Aedes sp. but also in C. quinquefasciatus mosquitoes, indicating that antiviral RNA interference in C. quinquefasciatus mosquitoes is similar to the described activities of RNAi in Aedes sp. mosquitoes. We also show that these have antiviral activity, since silencing of RNAi pathway effectors enhances viral replication. Moreover, our data suggest that RVFV does not encode a suppressor of RNAi. These findings point toward a significant role of RNAi in the control of RVFV in mosquitoes. IMPORTANCE Rift Valley fever virus (RVFV; Phlebovirus, Bunyaviridae) is an emerging zoonotic mosquito-borne pathogen of high relevance for human and animal health. Successful strategies of intervention in RVFV transmission by its mosquito vectors and the prevention of human and veterinary disease rely on a better understanding of the mechanisms that govern RVFV-vector interactions. Despite its medical importance, little is known about the factors that govern RVFV replication, dissemination, and transmission in the invertebrate host. Here we studied the role of the antiviral RNA interference immune pathways in the defense against RVFV in natural vector mosquitoes and mosquito cells and draw comparisons to the model insect Drosophila

  12. Relationship of climate, geography, and geology to the incidence of Rift Valley fever in Kenya during the 2006-2007 outbreak.

    Science.gov (United States)

    Hightower, Allen; Kinkade, Carl; Nguku, Patrick M; Anyangu, Amwayi; Mutonga, David; Omolo, Jared; Njenga, M Kariuki; Feikin, Daniel R; Schnabel, David; Ombok, Maurice; Breiman, Robert F

    2012-02-01

    We estimated Rift Valley fever (RVF) incidence as a function of geological, geographical, and climatological factors during the 2006-2007 RVF epidemic in Kenya. Location information was obtained for 214 of 340 (63%) confirmed and probable RVF cases that occurred during an outbreak from November 1, 2006 to February 28, 2007. Locations with subtypes of solonetz, calcisols, solonchaks, and planosols soil types were highly associated with RVF occurrence during the outbreak period. Increased rainfall and higher greenness measures before the outbreak were associated with increased risk. RVF was more likely to occur on plains, in densely bushed areas, at lower elevations, and in the Somalia acacia ecological zone. Cases occurred in three spatial temporal clusters that differed by the date of associated rainfall, soil type, and land usage.

  13. Factors associated with severe human Rift Valley fever in Sangailu, Garissa County, Kenya.

    Directory of Open Access Journals (Sweden)

    A Desirée LaBeaud

    2015-03-01

    Full Text Available Mosquito-borne Rift Valley fever virus (RVFV causes acute, often severe, disease in livestock and humans. To determine the exposure factors and range of symptoms associated with human RVF, we performed a population-based cross-sectional survey in six villages across a 40 km transect in northeastern Kenya.A systematic survey of the total populations of six Northeastern Kenyan villages was performed. Among 1082 residents tested via anti-RVFV IgG ELISA, seroprevalence was 15% (CI95%, 13-17%. Prevalence did not vary significantly among villages. Subject age was a significant factor, with 31% (154/498 of adults seropositive vs. only 2% of children ≤15 years (12/583. Seroprevalence was higher among men (18% than women (13%. Factors associated with seropositivity included a history of animal exposure, non-focal fever symptoms, symptoms related to meningoencephalitis, and eye symptoms. Using cluster analysis in RVFV positive participants, a more severe symptom phenotype was empirically defined as having somatic symptoms of acute fever plus eye symptoms, and possibly one or more meningoencephalitic or hemorrhagic symptoms. Associated with this more severe disease phenotype were older age, village, recent illness, and loss of a family member during the last outbreak. In multivariate analysis, sheltering livestock (aOR = 3.5 CI95% 0.93-13.61, P = 0.065, disposing of livestock abortus (aOR = 4.11, CI95% 0.63-26.79, P = 0.14, and village location (P = 0.009 were independently associated with the severe disease phenotype.Our results demonstrate that a significant proportion of the population in northeastern Kenya has been infected with RVFV. Village and certain animal husbandry activities were associated with more severe disease. Older age, male gender, herder occupation, killing and butchering livestock, and poor visual acuity were useful markers for increased RVFV infection. Formal vision testing may therefore prove to be a helpful, low-technology tool

  14. Roles of the Coding and Noncoding Regions of Rift Valley Fever Virus RNA Genome Segments in Viral RNA Packaging

    OpenAIRE

    Murakami, Shin; Terasaki, Kaori; Narayanan, Krishna; Makino, Shinji

    2012-01-01

    We characterized the RNA elements involved in the packaging of Rift Valley fever virus RNA genome segments, L, M, and S. The 5′-terminal 25 nucleotides of each RNA segment were equally competent for RNA packaging and carried an RNA packaging signal, which overlapped with the RNA replication signal. Only the deletion mutants of L RNA, but not full-length L RNA, were efficiently packaged, implying the possible requirement of RNA compaction for L RNA packaging.

  15. DoD-GEIS Rift Valley Fever Monitoring and Prediction System as a Tool for Defense and US Diplomacy

    Science.gov (United States)

    Anyamba, Assaf; Tucker, Compton J.; Linthicum, Kenneth J.; Witt, Clara J.; Gaydos, Joel C.; Russell, Kevin L.

    2011-01-01

    Over the last 10 years the Armed Forces Health Surveillance Center's Global Emerging Infections Surveillance and Response System (GEIS) partnering with NASA'S Goddard Space Flight Center and USDA's USDA-Center for Medical, Agricultural & Veterinary Entomology established and have operated the Rift Valley fever Monitoring and Prediction System to monitor, predict and assess the risk of Rift Valley fever outbreaks and other vector-borne diseases over Africa and the Middle East. This system is built on legacy DoD basic research conducted by Walter Reed Army Institute of Research overseas laboratory (US Army Medical Research Unit-Kenya) and the operational satellite environmental monitoring by NASA GSFC. Over the last 10 years of operation the system has predicted outbreaks of Rift Valley fever in the Horn of Africa, Sudan, South Africa and Mauritania. The ability to predict an outbreak several months before it occurs provides early warning to protect deployed forces, enhance public health in concerned countries and is a valuable tool use.d by the State Department in US Diplomacy. At the international level the system has been used by the Food and Agricultural Organization (FAD) and the World Health Organization (WHO) to support their monitoring, surveillance and response programs in the livestock sector and human health. This project is a successful testament of leveraging resources of different federal agencies to achieve objectives of force health protection, health and diplomacy.

  16. A need for One Health approach - lessons learned from outbreaks of Rift Valley fever in Saudi Arabia and Sudan.

    Science.gov (United States)

    Hassan, Osama Ahmed; Ahlm, Clas; Evander, Magnus

    2014-01-01

    Rift Valley fever (RVF) is an emerging viral zoonosis that impacts human and animal health. It is transmitted from animals to humans directly through exposure to blood, body fluids, or tissues of infected animals or via mosquito bites. The disease is endemic to Africa but has recently spread to Saudi Arabia and Yemen. Our aim was to compare two major outbreaks of RVF in Saudi Arabia (2000) and Sudan (2007) from a One Health perspective. Using the terms 'Saudi Arabia', 'Sudan', and 'RVF', articles were identified by searching PubMed, Google Scholar, and web pages of international organizations as well as local sources in Saudi Arabia and Sudan. The outbreak in Saudi Arabia caused 883 human cases, with a case fatality rate of 14% and more than 40,000 dead sheep and goats. In Sudan, 698 human cases of RVF were recognized (case fatality, 31.5%), but no records of affected animals were available. The ecology and environment of the affected areas were similar with irrigation canals and excessive rains providing an attractive habitat for mosquito vectors to multiply. The outbreaks resulted in livestock trade bans leading to a vast economic impact on the animal market in the two countries. The surveillance system in Sudan showed a lack of data management and communication between the regional and federal health authorities, while in Saudi Arabia which is the stronger economy, better capacity and contingency plans resulted in efficient countermeasures. Studies of the epidemiology and vectors were also performed in Saudi Arabia, while in Sudan these issues were only partly studied. We conclude that a One Health approach is the best option to mitigate outbreaks of RVF. Collaboration between veterinary, health, and environmental authorities both on national and regional levels is needed.

  17. A need for One Health approach – lessons learned from outbreaks of Rift Valley fever in Saudi Arabia and Sudan

    Directory of Open Access Journals (Sweden)

    Osama Ahmed Hassan

    2014-02-01

    Full Text Available Introduction: Rift Valley fever (RVF is an emerging viral zoonosis that impacts human and animal health. It is transmitted from animals to humans directly through exposure to blood, body fluids, or tissues of infected animals or via mosquito bites. The disease is endemic to Africa but has recently spread to Saudi Arabia and Yemen. Our aim was to compare two major outbreaks of RVF in Saudi Arabia (2000 and Sudan (2007 from a One Health perspective. Methods: Using the terms ‘Saudi Arabia’, ‘Sudan’, and ‘RVF’, articles were identified by searching PubMed, Google Scholar, and web pages of international organizations as well as local sources in Saudi Arabia and Sudan. Results: The outbreak in Saudi Arabia caused 883 human cases, with a case fatality rate of 14% and more than 40,000 dead sheep and goats. In Sudan, 698 human cases of RVF were recognized (case fatality, 31.5%, but no records of affected animals were available. The ecology and environment of the affected areas were similar with irrigation canals and excessive rains providing an attractive habitat for mosquito vectors to multiply. The outbreaks resulted in livestock trade bans leading to a vast economic impact on the animal market in the two countries. The surveillance system in Sudan showed a lack of data management and communication between the regional and federal health authorities, while in Saudi Arabia which is the stronger economy, better capacity and contingency plans resulted in efficient countermeasures. Studies of the epidemiology and vectors were also performed in Saudi Arabia, while in Sudan these issues were only partly studied. Conclusion: We conclude that a One Health approach is the best option to mitigate outbreaks of RVF. Collaboration between veterinary, health, and environmental authorities both on national and regional levels is needed.

  18. Phylogeography of Rift Valley Fever virus in Africa reveals multiple introductions in Senegal and Mauritania.

    Directory of Open Access Journals (Sweden)

    P O Ly Soumaré

    Full Text Available Rift Valley Fever (RVF virus (Family Bunyaviridae is an arthropod-borne RNA virus that infects primarily domestic ruminants and occasionally humans. RVF epizootics are characterized by numerous abortions and mortality among young animals. In humans, the illness is usually characterized by a mild self-limited febrile illness, which could progress to more serious complications. RVF virus is widespread and endemic in many regions of Africa. In Western Africa, several outbreaks have been reported since 1987 when the first major one occurred at the frontier of Senegal and Mauritania. Aiming to evaluate the spreading and molecular epidemiology in these countries, RVFV isolates from 1944 to 2008 obtained from 18 localities in Senegal and Mauritania and 15 other countries were investigated. Our results suggest that a more intense viral activity possibly took place during the last century compared to the recent past and that at least 5 introductions of RVFV took place in Senegal and Mauritania from distant African regions. Moreover, Barkedji in Senegal was possibly a hub associated with the three distinct entries of RVFV in West Africa.

  19. The role of signal transducer and activator of transcription 3 in Rift Valley fever virus infection

    Energy Technology Data Exchange (ETDEWEB)

    Pinkham, Chelsea; An, Soyeon; Lundberg, Lindsay; Bansal, Neha; Benedict, Ashwini; Narayanan, Aarthi; Kehn-Hall, Kylene, E-mail: kkehnhal@gmu.edu

    2016-09-15

    Rift Valley fever (RVF) is a zoonotic disease that can cause severe illness in humans and livestock, triggering spontaneous abortion in almost 100% of pregnant ruminants. In this study, we demonstrate that signal transducer and activator of transcription 3 (STAT3) is phosphorylated on its conserved tyrosine residue (Y705) following RVFV infection. This phosphorylation was dependent on a major virulence factor, the viral nonstructural protein NSs. Loss of STAT3 had little effect on viral replication, but rather resulted in cells being more susceptible to RVFV-induced cell death. Phosphorylated STAT3 translocated to the nucleus, coinciding with inhibition of fos, jun, and nr4a2 gene expression, and the presence of STAT3 and NSs at the nr4a2 promoter. NSs was found predominantly in the cytoplasm of STAT3 null cells, indicating that STAT3 influences NSs nuclear localization. Collectively, these data demonstrate that STAT3 functions in a pro-survival capacity through modulation of NSs localization. - Highlights: • STAT3 is phosphorylated on tyrosine residue 705 following RVFV infection. • Phosphorylation of STAT3 was dependent on the viral protein NSs. • STAT3 -/- MEFs were more susceptible to RVFV-induced cell death. • Loss of STAT3 led to an increase in pro-apoptotic gene expression. • STAT3 functions in a pro-survival capacity by modulation of NSs localization.

  20. Development of a Rift Valley fever virus viremia challenge model in sheep and goats.

    Science.gov (United States)

    Weingartl, Hana M; Miller, Myrna; Nfon, Charles; Wilson, William C

    2014-04-25

    Rift Valley fever virus (RVFV), a member of the family Bunyaviridae, causes severe to fatal disease in newborn ruminants, as well as abortions in pregnant animals; both preventable by vaccination. Availability of a challenge model is a pre-requisite for vaccine efficacy trials. Several modes of inoculation with RVFV ZH501 were tested on goats and sheep. Differences in development of infectious viremia were observed between animals inoculated with RVFV produced in mosquito C6/36 cells compared to Vero E6 cell-produced inoculum. Only C6/36-RVFV inoculation led to development of viremia in all inoculated sheep and goats. The C6/36 cell-produced RVFV appeared to be more infectious with earlier onset of viremia, especially in sheep, and may also more closely represent a field situation. Goats were somewhat more resistant to the disease development with lower and shorter infectious virus viremia, and with only some animals developing transient increase in rectal temperature in contrast to sheep. In conclusion, a challenge protocol suitable for goat and sheep vaccine efficacy studies was developed using subcutaneous inoculation of 10(7)PFU per animal with RVFV ZH501 produced in C6/36 cells. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  1. Modeling the Impact of Climate Change on the Dynamics of Rift Valley Fever

    Directory of Open Access Journals (Sweden)

    Saul C. Mpeshe

    2014-01-01

    Full Text Available A deterministic SEIR model of rift valley fever (RVF with climate change parameters was considered to compute the basic reproduction number ℛ0 and investigate the impact of temperature and precipitation on ℛ0. To study the effect of model parameters to ℛ0, sensitivity and elasticity analysis of ℛ0 were performed. When temperature and precipitation effects are not considered, ℛ0 is more sensitive to the expected number of infected Aedes spp. due to one infected livestock and more elastic to the expected number of infected livestock due to one infected Aedes spp. When climatic data are used, ℛ0 is found to be more sensitive and elastic to the expected number of infected eggs laid by Aedes spp. via transovarial transmission, followed by the expected number of infected livestock due to one infected Aedes spp. and the expected number of infected Aedes spp. due to one infected livestock for both regions Arusha and Dodoma. These results call for attention to parameters regarding incubation period, the adequate contact rate of Aedes spp. and livestock, the infective periods of livestock and Aedes spp., and the vertical transmission in Aedes species.

  2. Modeling the Impact of Climate Change on the Dynamics of Rift Valley Fever

    Science.gov (United States)

    Mpeshe, Saul C.; Luboobi, Livingstone S.; Nkansah-Gyekye, Yaw

    2014-01-01

    A deterministic SEIR model of rift valley fever (RVF) with climate change parameters was considered to compute the basic reproduction number ℛ 0 and investigate the impact of temperature and precipitation on ℛ 0. To study the effect of model parameters to ℛ 0, sensitivity and elasticity analysis of ℛ 0 were performed. When temperature and precipitation effects are not considered, ℛ 0 is more sensitive to the expected number of infected Aedes spp. due to one infected livestock and more elastic to the expected number of infected livestock due to one infected Aedes spp. When climatic data are used, ℛ 0 is found to be more sensitive and elastic to the expected number of infected eggs laid by Aedes spp. via transovarial transmission, followed by the expected number of infected livestock due to one infected Aedes spp. and the expected number of infected Aedes spp. due to one infected livestock for both regions Arusha and Dodoma. These results call for attention to parameters regarding incubation period, the adequate contact rate of Aedes spp. and livestock, the infective periods of livestock and Aedes spp., and the vertical transmission in Aedes species. PMID:24795775

  3. Rift valley fever surveillance in the lower Senegal river basin: update 10 years after the epidemic.

    Science.gov (United States)

    Thonnon, J; Picquet, M; Thiongane, Y; Lo, M; Sylla, R; Vercruysse, J

    1999-08-01

    After the Rift valley fever (RVF) epidemic of 1987 in the Senegal River Basin, RVF surveillance based on serosurveys has been conducted for 10 years. Serum samples were obtained from 1336 persons and from sheep and goats in selected areas, and these were tested for IgG/IgM RVF antibodies by ELISA. After a period of regular decrease in RVF prevalence in domestic animals until 1993, an epizootic was observed in all herds in 1994-95 with increases in IgM levels and abortions. During the same period, no human cases or RVF IgM were detected. The RVF IgG prevalence significantly correlated with date of birth: children born after 1987 have a low prevalence (5%) in clear contrast to the older population (25.3%) in Podor district. A retrospective analysis of rainfall and RVF prevalence in small domestic animals over the last 10 years showed that the re-emergence correlated with heavy rainfall. A general analysis of the risk of re-emergence and the efficiency of this RVF surveillance system are presented.

  4. Heat stability of the Rift Valley Fever Virus Clone 13 live vaccines

    Directory of Open Access Journals (Sweden)

    Samira Daouam

    2014-01-01

    Full Text Available Rift Valley Fever (RVF is an emerging zoonotic disease present in sub-Saharan Africa and the Arabian Peninsula. Vaccination of cattle against RVF with a RVF virus clone 13 (CL13 strain has proven to be efficacious, and avoids the side effects caused by other available live vaccines. In order to determine the temperature stability of the CL13 vaccine, lyophilized and liquid forms were tested and titrated for the presence of live virus after storage for various time periods at various temperatures. Results showed that the virus could be stored lyophilized at 4 °C for more than 12 months, with no reduction of infectivity. However, the vaccine was shown to be unstable at room temperature and at 37 °C in both lyophilized and liquid forms. This data shows that the CL13 vaccine is highly reliant on a cold chain, emphasizing the need for the vaccine to be made thermostable in order to allow for efficient vaccine storage and delivery in endemic tropical countries.

  5. Data-driven modeling to assess receptivity for Rift Valley Fever virus.

    Directory of Open Access Journals (Sweden)

    Christopher M Barker

    2013-11-01

    Full Text Available Rift Valley Fever virus (RVFV is an enzootic virus that causes extensive morbidity and mortality in domestic ruminants in Africa, and it has shown the potential to invade other areas such as the Arabian Peninsula. Here, we develop methods for linking mathematical models to real-world data that could be used for continent-scale risk assessment given adequate data on local host and vector populations. We have applied the methods to a well-studied agricultural region of California with [Formula: see text]1 million dairy cattle, abundant and competent mosquito vectors, and a permissive climate that has enabled consistent transmission of West Nile virus and historically other arboviruses. Our results suggest that RVFV outbreaks could occur from February-November, but would progress slowly during winter-early spring or early fall and be limited spatially to areas with early increases in vector abundance. Risk was greatest in summer, when the areas at risk broadened to include most of the dairy farms in the study region, indicating the potential for considerable economic losses if an introduction were to occur. To assess the threat that RVFV poses to North America, including what-if scenarios for introduction and control strategies, models such as this one should be an integral part of the process; however, modeling must be paralleled by efforts to address the numerous remaining gaps in data and knowledge for this system.

  6. Modeling the impact of climate change on the dynamics of Rift Valley Fever.

    Science.gov (United States)

    Mpeshe, Saul C; Luboobi, Livingstone S; Nkansah-Gyekye, Yaw

    2014-01-01

    A deterministic SEIR model of rift valley fever (RVF) with climate change parameters was considered to compute the basic reproduction number ℛ 0 and investigate the impact of temperature and precipitation on ℛ 0. To study the effect of model parameters to ℛ 0, sensitivity and elasticity analysis of ℛ 0 were performed. When temperature and precipitation effects are not considered, ℛ 0 is more sensitive to the expected number of infected Aedes spp. due to one infected livestock and more elastic to the expected number of infected livestock due to one infected Aedes spp. When climatic data are used, ℛ 0 is found to be more sensitive and elastic to the expected number of infected eggs laid by Aedes spp. via transovarial transmission, followed by the expected number of infected livestock due to one infected Aedes spp. and the expected number of infected Aedes spp. due to one infected livestock for both regions Arusha and Dodoma. These results call for attention to parameters regarding incubation period, the adequate contact rate of Aedes spp. and livestock, the infective periods of livestock and Aedes spp., and the vertical transmission in Aedes species.

  7. A fusion-inhibiting peptide against Rift Valley fever virus inhibits multiple, diverse viruses.

    Directory of Open Access Journals (Sweden)

    Jeffrey W Koehler

    Full Text Available For enveloped viruses, fusion of the viral envelope with a cellular membrane is critical for a productive infection to occur. This fusion process is mediated by at least three classes of fusion proteins (Class I, II, and III based on the protein sequence and structure. For Rift Valley fever virus (RVFV, the glycoprotein Gc (Class II fusion protein mediates this fusion event following entry into the endocytic pathway, allowing the viral genome access to the cell cytoplasm. Here, we show that peptides analogous to the RVFV Gc stem region inhibited RVFV infectivity in cell culture by inhibiting the fusion process. Further, we show that infectivity can be inhibited for diverse, unrelated RNA viruses that have Class I (Ebola virus, Class II (Andes virus, or Class III (vesicular stomatitis virus fusion proteins using this single peptide. Our findings are consistent with an inhibition mechanism similar to that proposed for stem peptide fusion inhibitors of dengue virus in which the RVFV inhibitory peptide first binds to both the virion and cell membranes, allowing it to traffic with the virus into the endocytic pathway. Upon acidification and rearrangement of Gc, the peptide is then able to specifically bind to Gc and prevent fusion of the viral and endocytic membranes, thus inhibiting viral infection. These results could provide novel insights into conserved features among the three classes of viral fusion proteins and offer direction for the future development of broadly active fusion inhibitors.

  8. Geographically weighted discriminant analysis of environmental conditions associated with Rift Valley fever outbreaks in South Africa.

    Science.gov (United States)

    Nicholas, Dennis E; Delamater, Paul L; Waters, Nigel M; Jacobsen, Kathryn H

    2016-05-01

    Rift Valley fever (RVF) is a zoonotic arboviral infection that has occurred across Africa and parts of the Middle East. Geographically weighted discriminant analysis (GWDA) is a spatially-adaptive extension of traditional discriminant analysis (DA) which has rarely been applied to infectious disease epidemiology research. This study compares the classification performance of GWDA and traditional DA when used to distinguish between locations where livestock are at risk or are not at risk for acquiring RVF virus (RVFV) using 699 case reports of RVF (affecting 18,894 animals) from two outbreaks in South Africa in 2008-2009 and 2010-2011. GWDA produced better results than traditional DA for all bandwidth and kernel combinations. The best GWDA model correctly classified 96.6% of the original data versus 84.5% obtained with traditional DA. With GWDA, false positives decreased from 10.9% to 3.7%, and false negatives decreased from 19.9% to 3.2%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Seroprevalence of Antibodies against Chikungunya, Dengue, and Rift Valley Fever Viruses after Febrile Illness Outbreak, Madagascar

    Science.gov (United States)

    Girmann, Mirko; Randriamampionona, Njary; Bialonski, Alexandra; Maus, Deborah; Krefis, Anne Caroline; Njarasoa, Christine; Rajanalison, Jeanne Fleury; Ramandrisoa, Herly Daniel; Randriarison, Maurice Lucien; May, Jürgen; Schmidt-Chanasit, Jonas; Rakotozandrindrainy, Raphael

    2012-01-01

    In October 2009, two–3 months after an outbreak of a febrile disease with joint pain on the eastern coast of Madagascar, we assessed serologic markers for chikungunya virus (CHIKV), dengue virus (DENV), and Rift Valley fever virus (RVFV) in 1,244 pregnant women at 6 locations. In 2 eastern coast towns, IgG seroprevalence against CHIKV was 45% and 23%; IgM seroprevalence was 28% and 5%. IgG seroprevalence against DENV was 17% and 11%. No anti-DENV IgM was detected. At 4 locations, 450–1,300 m high, IgG seroprevalence against CHIKV was 0%–3%, suggesting CHIKV had not spread to higher inland-altitudes. Four women had IgG against RVFV, probably antibodies from a 2008 epidemic. Most (78%) women from coastal locations with CHIKV-specific IgG reported joint pain and stiffness; 21% reported no symptoms. CHIKV infection was significantly associated with high bodyweight. The outbreak was an isolated CHIKV epidemic without relevant DENV co-transmission. PMID:23092548

  10. Attenuation and protective efficacy of Rift Valley fever phlebovirus rMP12-GM50 strain.

    Science.gov (United States)

    Ly, Hoai J; Nishiyama, Shoko; Lokugamage, Nandadeva; Smith, Jennifer K; Zhang, Lihong; Perez, David; Juelich, Terry L; Freiberg, Alexander N; Ikegami, Tetsuro

    2017-12-04

    Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to Africa and the Arabian Peninsula that affects sheep, cattle, goats, camels, and humans. Effective vaccination of susceptible ruminants is important for the prevention of RVF outbreaks. Live-attenuated RVF vaccines are in general highly immunogenic in ruminants, whereas residual virulence might be a concern for vulnerable populations. It is also important for live-attenuated strains to encode unique genetic markers for the differentiation from wild-type RVFV strains. In this study, we aimed to strengthen the attenuation profile of the MP-12 vaccine strain via the introduction of 584 silent mutations. To minimize the impact on protective efficacy, codon usage and codon pair bias were not de-optimized. The resulting rMP12-GM50 strain showed 100% protective efficacy with a single intramuscular dose, raising a 1:853 mean titer of plaque reduction neutralization test. Moreover, outbred mice infected with one of three pathogenic reassortant ZH501 strains, which encoded rMP12-GM50 L-, M-, or S-segments, showed 90%, 50%, or 30% survival, respectively. These results indicate that attenuation of the rMP12-GM50 strain is significantly attenuated via the L-, M-, and S-segments. Recombinant RVFV vaccine strains encoding similar silent mutations will be also useful for the surveillance of reassortant strains derived from vaccine strains in endemic countries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Mutational analysis of Rift Valley fever phlebovirus nucleocapsid protein indicates novel conserved, functional amino acids.

    Science.gov (United States)

    Mottram, Timothy J; Li, Ping; Dietrich, Isabelle; Shi, Xiaohong; Brennan, Benjamin; Varjak, Margus; Kohl, Alain

    2017-12-21

    Rift Valley fever phlebovirus (RVFV; Phenuiviridae, Phlebovirus) is an important mosquito-borne pathogen of both humans and ruminants. The RVFV genome is composed of tripartite, single stranded, negative or ambisense RNAs. The small (S) segment encodes both the nucleocapsid protein (N) and the non-structural protein (NSs). The N protein is responsible for the formation of the viral ribonucleoprotein (RNP) complexes, which are essential in the virus life cycle and for the transcription and replication of the viral genome. There is currently limited knowledge surrounding the roles of the RVFV nucleocapsid protein in viral infection other than its key functions: N protein multimerisation, encapsidation of the RNA genome and interactions with the RNA-dependent RNA polymerase, L. By bioinformatic comparison of the N sequences of fourteen phleboviruses, mutational analysis, minigenome assays and packaging assays, we have further characterised the RVFV N protein. Amino acids P11 and F149 in RVFV N play an essential role in the function of RNPs and are neither associated with N protein multimerisation nor known nucleocapsid protein functions and may have additional roles in the virus life cycle. Amino acid Y30 exhibited increased minigenome activity despite reduced RNA binding capacity. Additionally, we have determined that the N-terminal arm of N protein is not involved in N-L interactions. Elucidating the fundamental processes that involve the nucleocapsid protein will add to our understanding of this important viral protein and may influence future studies in the development of novel antiviral strategies.

  12. Interim Report on SNP analysis and forensic microarray probe design for South American hemorrhagic fever viruses, tick-borne encephalitis virus, henipaviruses, Old World Arenaviruses, filoviruses, Crimean-Congo hemorrhagic fever viruses, Rift Valley fever

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    Jaing, C; Gardner, S

    2012-06-05

    The goal of this project is to develop forensic genotyping assays for select agent viruses, enhancing the current capabilities for the viral bioforensics and law enforcement community. We used a multipronged approach combining bioinformatics analysis, PCR-enriched samples, microarrays and TaqMan assays to develop high resolution and cost effective genotyping methods for strain level forensic discrimination of viruses. We have leveraged substantial experience and efficiency gained through year 1 on software development, SNP discovery, TaqMan signature design and phylogenetic signature mapping to scale up the development of forensics signatures in year 2. In this report, we have summarized the whole genome wide SNP analysis and microarray probe design for forensics characterization of South American hemorrhagic fever viruses, tick-borne encephalitis viruses and henipaviruses, Old World Arenaviruses, filoviruses, Crimean-Congo hemorrhagic fever virus, Rift Valley fever virus and Japanese encephalitis virus.

  13. Functional analysis of Rift Valley fever virus NSs encoding a partial truncation.

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    Jennifer A Head

    Full Text Available Rift Valley fever virus (RVFV, belongs to genus Phlebovirus of the family Bunyaviridae, causes high rates of abortion and fetal malformation in infected ruminants as well as causing neurological disorders, blindness, or lethal hemorrhagic fever in humans. RVFV is classified as a category A priority pathogen and a select agent in the U.S., and currently there are no therapeutics available for RVF patients. NSs protein, a major virulence factor of RVFV, inhibits host transcription including interferon (IFN-β mRNA synthesis and promotes degradation of dsRNA-dependent protein kinase (PKR. NSs self-associates at the C-terminus 17 aa., while NSs at aa.210-230 binds to Sin3A-associated protein (SAP30 to inhibit the activation of IFN-β promoter. Thus, we hypothesize that NSs function(s can be abolished by truncation of specific domains, and co-expression of nonfunctional NSs with intact NSs will result in the attenuation of NSs function by dominant-negative effect. Unexpectedly, we found that RVFV NSs truncated at aa. 6-30, 31-55, 56-80, 81-105, 106-130, 131-155, 156-180, 181-205, 206-230, 231-248 or 249-265 lack functions of IFN-β mRNA synthesis inhibition and degradation of PKR. Truncated NSs were less stable in infected cells, while nuclear localization was inhibited in NSs lacking either of aa.81-105, 106-130, 131-155, 156-180, 181-205, 206-230 or 231-248. Furthermore, none of truncated NSs had exhibited significant dominant-negative functions for NSs-mediated IFN-β suppression or PKR degradation upon co-expression in cells infected with RVFV. We also found that any of truncated NSs except for intact NSs does not interact with RVFV NSs even in the presence of intact C-terminus self-association domain. Our results suggest that conformational integrity of NSs is important for the stability, cellular localization and biological functions of RVFV NSs, and the co-expression of truncated NSs does not exhibit dominant-negative phenotype.

  14. Exploratory space-time analyses of Rift Valley Fever in South Africa in 2008-2011.

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    Raphaëlle Métras

    Full Text Available Rift Valley fever (RVF is a zoonotic arbovirosis for which the primary hosts are domestic livestock (cattle, sheep and goats. RVF was first described in South Africa in 1950-1951. Mechanisms for short and long distance transmission have been hypothesised, but there is little supporting evidence. Here we describe RVF occurrence and spatial distribution in South Africa in 2008-11, and investigate the presence of a contagious process in order to generate hypotheses on the different mechanisms of transmission.A total of 658 cases were extracted from World Animal Health Information Database. Descriptive statistics, epidemic curves and maps were produced. The space-time K-function was used to test for evidence of space-time interaction. Five RVF outbreak waves (one in 2008, two in 2009, one in 2010 and one in 2011 of varying duration, location and size were reported. About 70% of cases (n = 471 occurred in 2010, when the epidemic was almost country-wide. No strong evidence of space-time interaction was found for 2008 or the second wave in 2009. In the first wave of 2009, a significant space-time interaction was detected for up to one month and over 40 km. In 2010 and 2011 a significant intense, short and localised space-time interaction (up to 3 days and 15 km was detected, followed by one of lower intensity (up to 2 weeks and 35 to 90 km.The description of the spatiotemporal patterns of RVF in South Africa between 2008 and 2011 supports the hypothesis that during an epidemic, disease spread may be supported by factors other than active vector dispersal. Limitations of under-reporting and space-time K-function properties are discussed. Further spatial analyses and data are required to explain factors and mechanisms driving RVF spread.

  15. Evidence of Rift Valley fever seroprevalence in the Sahrawi semi-nomadic pastoralist system, Western Sahara.

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    Di Nardo, Antonello; Rossi, Davide; Saleh, Saleh M Lamin; Lejlifa, Saleh M; Hamdi, Sidumu J; Di Gennaro, Annapia; Savini, Giovanni; Thrusfield, Michael V

    2014-04-24

    The increasing global importance of Rift Valley fever (RVF) is clearly demonstrated by its geographical expansion. The presence of a wide range of host and vector species, and the epidemiological characteristics of RVF, have led to concerns that epidemics will continue to occur in previously unaffected regions of Africa. The proximity of the Sahrawi territories of Western Sahara to endemic countries, such as Mauritania, Senegal, and Mali with periodic isolation of virus and serological evidence of RVF, and the intensive livestock trade in the region results in a serious risk of RVF spread in the Sahrawi territories, and potentially from there to the Maghreb and beyond. A sero-epidemiological survey was conducted in the Saharawi territories between March and April 2008 to investigate the possible presence of the RVF virus (RVFV) and associated risk factors. A two-stage cluster sampling design was used, incorporating 23 sampling sites. A total of 982 serum samples was collected from 461 sheep, 463 goats and 58 camels. Eleven samples (0.97%) tested positive for IgG against the RVFV. There were clusters of high seroprevalence located mostly in the Tifariti (7.69%) and Mehaires (7.14%) regions, with the Tifariti event having been found in one single flock (4/26 positive animals). Goats and older animals were at a significantly increased risk being seropositive (p = 0.007 and p = 0.007, respectively). The results suggest potential RVF activity in the study area, where intense livestock movement and trade with neighbouring countries might be considered as a primary determinant in the spread of the disease. The importance of a continuous field investigation is reinforced, in light of the risk of RVF expansion to historically unaffected regions of Africa.

  16. Modelling the effects of seasonality and socioeconomic impact on the transmission of Rift Valley fever virus

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    Xiao, Yanyu; Beier, John C.; Cantrell, Robert Stephen; Cosner, Chris; DeAngelis, Donald L.; Ruan, Shigui

    2015-01-01

    Rift Valley fever (RVF) is an important mosquito-borne viral zoonosis in Africa and the Middle East that causes human deaths and significant economic losses due to huge incidences of death and abortion among infected livestock. Outbreaks of RVF are sporadic and associated with both seasonal and socioeconomic effects. Here we propose an almost periodic three-patch model to investigate the transmission dynamics of RVF virus (RVFV) among ruminants with spatial movements. Our findings indicate that, in Northeastern Africa, human activities, including those associated with the Eid al Adha feast, along with a combination of climatic factors such as rainfall level and hydrological variations, contribute to the transmission and dispersal of the disease pathogen. Moreover, sporadic outbreaks may occur when the two events occur together: 1) abundant livestock are recruited into areas at risk from RVF due to the demand for the religious festival and 2) abundant numbers of mosquitoes emerge. These two factors have been shown to have impacts on the severity of RVF outbreaks. Our numerical results present the transmission dynamics of the disease pathogen over both short and long periods of time, particularly during the festival time. Further, we investigate the impact on patterns of disease outbreaks in each patch brought by festival- and seasonal-driven factors, such as the number of livestock imported daily, the animal transportation speed from patch to patch, and the death rate induced by ceremonial sacrifices. In addition, our simulations show that when the time for festival preparation starts earlier than usual, the risk of massive disease outbreaks rises, particularly in patch 3 (the place where the religious ceremony will be held).

  17. Modelling the effects of seasonality and socioeconomic impact on the transmission of rift valley Fever virus.

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    Yanyu Xiao

    2015-01-01

    Full Text Available Rift Valley fever (RVF is an important mosquito-borne viral zoonosis in Africa and the Middle East that causes human deaths and significant economic losses due to huge incidences of death and abortion among infected livestock. Outbreaks of RVF are sporadic and associated with both seasonal and socioeconomic effects. Here we propose an almost periodic three-patch model to investigate the transmission dynamics of RVF virus (RVFV among ruminants with spatial movements. Our findings indicate that, in Northeastern Africa, human activities, including those associated with the Eid al Adha feast, along with a combination of climatic factors such as rainfall level and hydrological variations, contribute to the transmission and dispersal of the disease pathogen. Moreover, sporadic outbreaks may occur when the two events occur together: 1 abundant livestock are recruited into areas at risk from RVF due to the demand for the religious festival and 2 abundant numbers of mosquitoes emerge. These two factors have been shown to have impacts on the severity of RVF outbreaks. Our numerical results present the transmission dynamics of the disease pathogen over both short and long periods of time, particularly during the festival time. Further, we investigate the impact on patterns of disease outbreaks in each patch brought by festival- and seasonal-driven factors, such as the number of livestock imported daily, the animal transportation speed from patch to patch, and the death rate induced by ceremonial sacrifices. In addition, our simulations show that when the time for festival preparation starts earlier than usual, the risk of massive disease outbreaks rises, particularly in patch 3 (the place where the religious ceremony will be held.

  18. Evidence for circulation of the rift valley fever virus among livestock in the union of Comoros.

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    Matthieu Roger

    Full Text Available Rift Valley fever virus (RVFV is an arthropod-borne phlebovirus reported to be circulating in most parts of Africa. Since 2009, RVFV has been suspected of continuously circulating in the Union of Comoros. To estimate the incidence of RVFV antibody acquisition in the Comorian ruminant population, 191 young goats and cattle were selected in six distinct zones and sampled periodically from April 2010 to August 2011. We found an estimated incidence of RVFV antibody acquisition of 17.5% (95% confidence interval (CI: [8.9-26.1] with a significant difference between islands (8.2% in Grande Comore, 72.3% in Moheli and 5.8% in Anjouan. Simultaneously, a longitudinal entomological survey was conducted and ruminant trade-related information was collected. No RVFV RNA was detected out of the 1,568 blood-sucking caught insects, including three potential vectors of RVFV mosquito species. Our trade survey suggests that there is a continuous flow of live animals from eastern Africa to the Union of Comoros and movements of ruminants between the three Comoro islands. Finally, a cross-sectional study was performed in August 2011 at the end of the follow-up. We found an estimated RVFV antibody prevalence of 19.3% (95% CI: [15.6%-23.0%]. Our findings suggest a complex RVFV epidemiological cycle in the Union of Comoros with probable inter-islands differences in RVFV circulation patterns. Moheli, and potentially Anjouan, appear to be acting as endemic reservoir of infection whereas RVFV persistence in Grande Comore could be correlated with trade in live animals with the eastern coast of Africa. More data are needed to estimate the real impact of the disease on human health and on the national economy.

  19. Epidemiologic and Environmental Risk Factors of Rift Valley Fever in Southern Africa from 2008 to 2011.

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    Glancey, Margaret M; Anyamba, Assaf; Linthicum, Kenneth J

    2015-08-01

    Rift Valley fever (RVF) outbreaks have been associated with periods of widespread and above-normal rainfall over several months. Knowledge on the environmental factors influencing disease transmission dynamics has provided the basis for developing models to predict RVF outbreaks in Africa. From 2008 to 2011, South Africa experienced the worst wave of RVF outbreaks in almost 40 years. We investigated rainfall-associated environmental factors in southern Africa preceding these outbreaks. RVF epizootic records obtained from the World Animal Health Information Database (WAHID), documenting livestock species affected, location, and time, were analyzed. Environmental variables including rainfall and satellite-derived normalized difference vegetation index (NDVI) data were collected and assessed in outbreak regions to understand the underlying drivers of the outbreaks. The predominant domestic vertebrate species affected in 2008 and 2009 were cattle, when outbreaks were concentrated in the eastern provinces of South Africa. In 2010 and 2011, outbreaks occurred in the interior and southern provinces affecting over 16,000 sheep. The highest number of cases occurred between January and April but epidemics occurred in different regions every year, moving from the northeast of South Africa toward the southwest with each progressing year. The outbreaks showed a pattern of increased rainfall preceding epizootics ranging from 9 to 152 days; however, NDVI and rainfall were less correlated with the start of the outbreaks than has been observed in eastern Africa. Analyses of the multiyear RVF outbreaks of 2008 to 2011 in South Africa indicated that rainfall, NDVI, and other environmental and geographical factors, such as land use, drainage, and topography, play a role in disease emergence. Current and future investigations into these factors will be able to contribute to improving spatial accuracy of models to map risk areas, allowing adequate time for preparation and prevention

  20. Prevalence of antibodies against Rift Valley fever virus in Kenyan wildlife

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    EVANS, A.; GAKUYA, F.; PAWESKA, J. T.; ROSTAL, M.; AKOOLO, L.; VAN VUREN, P. J.; MANYIBE, T.; MACHARIA, J. M.; KSIAZEK, T. G.; FEIKIN, D. R.; BREIMAN, R. F.; KARIUKI NJENGA, M.

    2008-01-01

    SUMMARY Rift Valley fever virus (RVFV) is an arbovirus associated with periodic outbreaks, mostly on the African continent, of febrile disease accompanied by abortion in livestock, and a severe, fatal haemorrhagic syndrome in humans. However, the maintenance of the virus during the inter-epidemic period (IEP) when there is low or no disease activity detected in livestock or humans has not been determined. This study report prevalence of RVFV-neutralizing antibodies in sera (n=896) collected from 16 Kenyan wildlife species including at least 35% that were born during the 1999–2006 IEP. Specimens from seven species had detectable neutralizing antibodies against RVFV, including African buffalo, black rhino, lesser kudu, impala, African elephant, kongoni, and waterbuck. High RVFV antibody prevalence (>15%) was observed in black rhinos and ruminants (kudu, impala, buffalo, and waterbuck) with the highest titres (up to 1:1280) observed mostly in buffalo, including animals born during the IEP. All lions, giraffes, plains zebras, and warthogs tested were either negative or less than two animals in each species had low (⩽1:16) titres of RVFV antibodies. Of 249 sera collected from five wildlife species during the 2006–2007 outbreak, 16 out of 19 (84%) of the ruminant (gerenuk, waterbuck, and eland) specimens had RVFV-neutralizing titres ⩾1:80. These data provide evidence that wild ruminants are infected by RVFV but further studies are required to determine whether these animals play a role in the virus maintenance between outbreaks and virus amplification prior to a noticeable outbreak. PMID:17988425

  1. Seroprevalence of Infections with Dengue, Rift Valley Fever and Chikungunya Viruses in Kenya, 2007.

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    Caroline Ochieng

    Full Text Available Arthropod-borne viruses are a major constituent of emerging infectious diseases worldwide, but limited data are available on the prevalence, distribution, and risk factors for transmission in Kenya and East Africa. In this study, we used 1,091 HIV-negative blood specimens from the 2007 Kenya AIDS Indicator Survey (KAIS 2007 to test for the presence of IgG antibodies to dengue virus (DENV, chikungunya virus (CHIKV and Rift Valley fever virus (RVFV.The KAIS 2007 was a national population-based survey conducted by the Government of Kenya to provide comprehensive information needed to address the HIV/AIDS epidemic. Antibody testing for arboviruses was performed on stored blood specimens from KAIS 2007 through a two-step sandwich IgG ELISA using either commercially available kits or CDC-developed assays. Out of the 1,091 samples tested, 210 (19.2% were positive for IgG antibodies against at least one of the three arboviruses. DENV was the most common of the three viruses tested (12.5% positive, followed by RVFV and CHIKV (4.5% and 0.97%, respectively. For DENV and RVFV, the participant's province of residence was significantly associated (P≤.01 with seropositivity. Seroprevalence of DENV and RVFV increased with age, while there was no correlation between province of residence/age and seropositivity for CHIKV. Females had twelve times higher odds of exposure to CHIK as opposed to DENV and RVFV where both males and females had the same odds of exposure. Lack of education was significantly associated with a higher odds of previous infection with either DENV or RVFV (p <0.01. These data show that a number of people are at risk of arbovirus infections depending on their geographic location in Kenya and transmission of these pathogens is greater than previously appreciated. This poses a public health risk, especially for DENV.

  2. Perceived risk factors and risk pathways of Rift Valley fever in cattle in Ijara district, Kenya

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    Nelson O. Owange

    2014-02-01

    Full Text Available Ijara district in Kenya was one of the hotspots of Rift Valley fever (RVF during the 2006/2007 outbreak, which led to human and animal deaths causing major economic losses. The main constraint for the control and prevention of RVF is inadequate knowledge of the risk factors for its occurrence and maintenance. This study was aimed at understanding the perceived risk factors and risk pathways of RVF in cattle in Ijara to enable the development of improved community-based disease surveillance, prediction, control and prevention. A cross-sectional study was carried out from September 2012 to June 2013. Thirty-one key informant interviews were conducted with relevant stakeholders to determine the local pastoralists’ understanding of risk factors and risk pathways of RVF in cattle in Ijara district. All the key informants perceived the presence of high numbers of mosquitoes and large numbers of cattle to be the most important risk factors contributing to the occurrence of RVF in cattle in Ijara. Key informants classified high rainfall as the most important (12/31 to an important (19/31 risk factor. The main risk pathways were infected mosquitoes that bite cattle whilst grazing and at watering points as well as close contact between domestic animals and wildlife. The likelihood of contamination of the environment as a result of poor handling of carcasses and aborted foetuses during RVF outbreaks was not considered an important pathway. There is therefore a need to conduct regular participatory community awareness sessions on handling of animal carcasses in terms of preparedness, prevention and control of any possible RVF epizootics. Additionally, monitoring of environmental conditions to detect enhanced rainfall and flooding should be prioritised for preparedness.

  3. Safety and Efficacy Profile of Commercial Veterinary Vaccines against Rift Valley Fever: A Review Study

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    Moataz Alhaj

    2016-01-01

    Full Text Available Rift Valley Fever (RVF is an infectious illness with serious clinical manifestations and health consequences in humans as well as a wide range of domestic ruminants. This review provides significant information about the prevention options of RVF along with the safety-efficacy profile of commercial vaccines and some of RVF vaccination strategies. Information presented in this paper was obtained through a systematic investigation of published data about RVF vaccines. Like other viral diseases, the prevention of RVF relies heavily on immunization of susceptible herds with safe and cost-effective vaccine that is able to confer long-term protective immunity. Several strains of RVF vaccines have been developed and are available in commercial production including Formalin-Inactivated vaccine, live attenuated Smithburn vaccine, and the most recent Clone13. Although Formalin-Inactivated vaccine and live attenuated Smithburn vaccine are immunogenic and widely used in prevention programs, they proved to be accompanied by significant concerns. Despite Clone13 vaccine being suggested as safe in pregnant ewes and as highly immunogenic along with its potential for differentiating infected from vaccinated animals (DIVA, a recent study raised concerns about the safety of the vaccine during the first trimester of gestation. Accordingly, RVF vaccines that are currently available in the market to a significant extent do not fulfill the requirements of safety, potency, and DIVA. These adverse effects stressed the need for developing new vaccines with an excellent safety profile to bridge the gap in safety and immunity. Bringing RVF vaccine candidates to local markets besides the absence of validated serological test for DIVA remain the major challenges of RVF control.

  4. Rift Valley fever vaccines: an overview of the safety and efficacy of the live-attenuated MP-12 vaccine candidate.

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    Ikegami, Tetsuro

    2017-06-01

    Rift Valley fever (RVF) is a mosquito-borne zoonotic viral disease endemic to Africa and the Arabian Peninsula. High rates of abortion among infected ruminants and hemorrhagic fever in infected humans are major public health concerns. Commercially available veterinary RVF vaccines are important for preventing the spread of the Rift Valley fever virus (RVFV) in endemic countries; however, RVFV outbreaks continue to occur frequently in endemic countries in the 21st century. In the U.S., the live-attenuated MP-12 vaccine has been developed for both animal and human vaccination. This vaccine strain is well attenuated, and a single dose induces neutralizing antibodies in both ruminants and humans. Areas covered: This review describes scientific evidences of MP-12 vaccine efficacy and safety, as well as MP-12 variants recently developed by reverse genetics, in comparison with other RVF vaccines. Expert commentary: The containment of active RVF outbreaks and long-term protection from RVF exposure to infected mosquitoes are important goals for RVF vaccination. MP-12 vaccine will allow immediate vaccination of susceptible animals in case of an unexpected RVF outbreak in the U.S., whereas MP-12 vaccine may be also useful for the RVF control in endemic regions.

  5. Temperature-sensitive mutations for live-attenuated Rift Valley fever vaccines: Implications from other RNA viruses

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    Shoko eNishiyama

    2015-08-01

    Full Text Available Rift Valley fever (RVF is a mosquito-borne zoonotic disease endemic to the African continent. RVF is characterized by high rate of abortions in ruminants and hemorrhagic fever, encephalitis or blindness in humans. RVF is caused by the Rift Valley fever virus (RVFV: genus Phlebovirus, family Bunyaviridae. Vaccination is the only known effective strategy to prevent the disease, but there are no licensed RVF vaccines available for humans. A live-attenuated vaccine candidate derived from the wild-type pathogenic Egyptian ZH548 strain, MP-12, has been conditionally licensed for veterinary use in the United States. MP-12 displays a temperature-sensitive (ts phenotype and does not replicate at 41oC. The ts mutation limits viral replication at a specific body temperature and may lead to an attenuation of the virus. Here we will review well-characterized ts mutations for RNA viruses, and further discuss the potential in designing novel live-attenuated vaccines for RVF.

  6. Transmission of Rift Valley fever virus from European-breed lambs to Culex pipiens mosquitoes.

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    Rianka P M Vloet

    2017-12-01

    Full Text Available Rift Valley fever virus (RVFV is a mosquito-borne bunyavirus of the genus Phlebovirus that is highly pathogenic to ruminants and humans. The disease is currently confined to Africa and the Arabian Peninsula, but globalization and climate change may facilitate introductions of the virus into currently unaffected areas via infected animals or mosquitoes. The consequences of such an introduction will depend on environmental factors, the availability of susceptible ruminants and the capacity of local mosquitoes to transmit the virus. We have previously demonstrated that lambs native to the Netherlands are highly susceptible to RVFV and we here report the vector competence of Culex (Cx. pipiens, the most abundant and widespread mosquito species in the country. Vector competence was first determined after artificial blood feeding of laboratory-reared mosquitoes using the attenuated Clone 13 strain. Subsequently, experiments with wild-type RVFV and mosquitoes hatched from field-collected eggs were performed. Finally, the transmission of RVFV from viremic lambs to mosquitoes was studied.Artificial feeding experiments using Clone 13 demonstrated that indigenous, laboratory-reared Cx. pipiens mosquitoes are susceptible to RVFV and that the virus can be transmitted via their saliva. Experiments with wild-type RVFV and mosquitoes hatched from field-collected eggs confirmed the vector competence of Cx. pipiens mosquitoes from the Netherlands. To subsequently investigate transmission of the virus under more natural conditions, mosquitoes were allowed to feed on RVFV-infected lambs during the viremic period. We found that RVFV is efficiently transmitted from lambs to mosquitoes, although transmission was restricted to peak viremia. Interestingly, in the mosquito-exposed skin samples, replication of RVFV was detected in previously unrecognized target cells.We here report the vector competence of Cx. pipiens mosquitoes from the Netherlands for RVFV. Both

  7. Risk analysis of inter-species reassortment through a Rift Valley fever phlebovirus MP-12 vaccine strain.

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    Hoai J Ly

    Full Text Available Rift Valley fever (RVF is a mosquito-borne zoonotic disease endemic to Africa and the Arabian Peninsula. The causative agent, Rift Valley fever phlebovirus (RVFV, belongs to the genus Phlebovirus in the family Phenuiviridae and causes high rates of abortions in ruminants, and hemorrhagic fever, encephalitis, or blindness in humans. Viral maintenance by mosquito vectors has led to sporadic RVF outbreaks in ruminants and humans in endemic countries, and effective vaccination of animals and humans may minimize the impact of this disease. A live-attenuated MP-12 vaccine strain is one of the best characterized RVFV strains, and was conditionally approved as a veterinary vaccine in the U.S. Live-attenuated RVF vaccines including MP-12 strain may form reassortant strains with other bunyavirus species. This study thus aimed to characterize the occurrence of genetic reassortment between the MP-12 strain and bunyavirus species closely related to RVFV. The Arumowot virus (AMTV and Gouleako goukovirus (GOLV, are transmitted by mosquitoes in Africa. The results of this study showed that GOLV does not form detectable reassortant strains with the MP-12 strain in co-infected C6/36 cells. The AMTV also did not form any reassortant strains with MP-12 strain in co-infected C6/36 cells, due to the incompatibility among N, L, and Gn/Gc proteins. A lack of reassortant formation could be due to a functional incompatibility of N and L proteins derived from heterologous species, and due to a lack of packaging via heterologous Gn/Gc proteins. The MP-12 strain did, however, randomly exchange L-, M-, and S-segments with a genetic variant strain, rMP12-GM50, in culture cells. The MP-12 strain is thus unlikely to form any reassortant strains with AMTV or GOLV in nature.

  8. Short interfering RNA inhibits Rift Valley fever virus replication and degradation of protein kinase R in human cells

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    Bonto Faburay

    2016-11-01

    Full Text Available Rift Valley fever virus (RVFV is a mosquito-borne zoonotic pathogen causing severe outbreaks in humans and livestock in sub-Saharan Africa and the Arabian Peninsula. Human infections are characterized by fever, sometimes leading to encephalitis, retinitis, hemorrhagic fever and occasionally death. There are currently no fully licensed vaccines or effective therapies for human use. Gene silencing mediated by double-stranded short interfering RNA (siRNA is a sequence-specific, highly conserved mechanism in eukaryotes, which serves as an antiviral defence mechanism. Here, we demonstrate that siRNA duplexes directed against the RVFV nucleoprotein can effectively inhibit RVFV replication in human (MRC5 cells and African green monkey cells (Vero E6 cells. Using these cells, we demonstrate that individual or complex siRNAs, targeting the RVFV nucleoprotein gene completely abrogate viral protein expression and prevent degradation of the host innate antiviral factor, protein kinase R (PKR. Importantly, pre-treatment of cells with the nucleoprotein-specific siRNAs markedly reduces the virus titer. The antiviral effect of the siRNAs was not attributable to interferon or the interferon response effector molecule, protein kinase R. Thus, the antiviral activity of RVFV nucleoprotein-specific siRNAs may provide novel therapeutic strategy against RVFV infections in animals and humans.

  9. Rift Valley fever virus-infected mosquito ova and associated pathology: possible implications for endemic maintenance

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    Romoser WS

    2011-09-01

    Full Text Available William S Romoser1, Marco Neira Oviedo1, Kriangkrai Lerdthusnee2, Lisa A Patrican3, Michael J Turell4, David J Dohm4, Kenneth J Linthicum5, Charles L Bailey61Department of Biomedical Sciences, College of Osteopathic Medicine, Tropical Disease Institute, Ohio University, Athens, Ohio, USA; 2Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand; 3Infectious Disease Division, National Center for Medical Intelligence, Fort Detrick, Frederick, Maryland, USA; 4Department of Vector Assessment, Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, USA; 5Center for Medical, Agricultural, and Veterinary Entomology, United States Department of Agriculture – Agricultural Research Service, Gainesville, Florida, USA; 6National Center for Biodefense and Infectious Disease, School of Systems Biology, College of Science, George Mason University, Manassas, Virginia, USABackground: Endemic/enzootic maintenance mechanisms like vertical transmission (pathogen passage from infected adults to their offspring are central in the epidemiology of zoonotic pathogens. In Kenya, Rift Valley fever virus (RVFV may be maintained by vertical transmission in ground-pool mosquitoes such as Aedes mcintoshi. RVFV can cause serious morbidity and mortality in humans and livestock. Past epidemics/epizootics have occurred in sub-Saharan Africa but, since the late 1970s, RVFV has also appeared in North Africa and the Middle East. Preliminary results revealed RVFV-infected eggs in Ae. mcintoshi after virus injection into the hemocoel after the first of two blood meals, justifying further study.Methods: Mosquitoes were collected from an artificially flooded water-catching depression along a stream in Kenya, shipped live to the USA, and studied using an immunocytochemical method for RVFV-antigen localization in mosquito sections.Results and conclusion: After virus injection into the

  10. Multilevel Methodology for Simulation of Spatio-Temporal Systems with Heterogeneous Activity; Application to Spread of Valley Fever Fungus

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    Jammalamadaka, Rajanikanth

    2009-01-01

    This report consists of a dissertation submitted to the faculty of the Department of Electrical and Computer Engineering, in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Graduate College, The University of Arizona, 2008. Spatio-temporal systems with heterogeneity in their structure and behavior have two major problems associated with them. The first one is that such complex real world systems extend over very large spatial and temporal domains and consume so many computational resources to simulate that they are infeasible to study with current computational platforms. The second one is that the data available for understanding such systems is limited because they are spread over space and time making it hard to obtain micro and macro measurements. This also makes it difficult to get the data for validation of their constituent processes while simultaneously considering their global behavior. For example, the valley fever fungus considered in this dissertation is spread over a large spatial grid in the arid Southwest and typically needs to be simulated over several decades of time to obtain useful information. It is also hard to get the temperature and moisture data (which are two critical factors on which the survival of the valley fever fungus depends) at every grid point of the spatial domain over the region of study. In order to address the first problem, we develop a method based on the discrete event system specification which exploits the heterogeneity in the activity of the spatio-temporal system and which has been shown to be effective in solving relatively simple partial differential equation systems. The benefit of addressing the first problem is that it now makes it feasible to address the second problem. We address the second problem by making use of a multilevel methodology based on modeling and simulation and systems theory. This methodology helps us in the construction of models with different resolutions (base and

  11. Multiplex detection of IgG and IgM to Rift Valley fever virus nucleoprotein, nonstructural proteins, and glycoprotein in ovine and bovine

    Science.gov (United States)

    A multiplex fluorescence microsphere immunoassay (FMIA) was used to detect bovine and ovine IgM and IgG antibodies to several Rift Valley fever virus (RVFV) proteins, including the major surface glycoprotein, Gn; the nonstructural proteins, NSs and NSm; and the nucleoprotein, N. Target antigens were...

  12. Diversity and ecological ranges of plant species from dry inter-Andean valleys

    DEFF Research Database (Denmark)

    Quintana, Catalina

    found on steep slopes and in ravines. These areas of original dry valley vegetation preserve many wild relatives of cultivated plants on the one hand and old lineages of other wild plant groups. Dry inter-Andean valleys (DIAVs) in Ecuador therefore makeup a biodiversity hot spot for both plants...... that there were significant, contrasting patterns between life forms (trees, herbs and shrubs) and that combining trees and shrubs in one broad category confound patterns and ecological processes. 3) This paper demonstrates that 70% of species collected in Ecuadorian DIAVs are shared amongst dry forests...

  13. Wetlands, wild Bovidae species richness and sheep density delineate risk of Rift Valley fever outbreaks in the African continent and Arabian Peninsula.

    Directory of Open Access Journals (Sweden)

    Michael G Walsh

    2017-07-01

    Full Text Available Rift Valley fever (RVF is an emerging, vector-borne viral zoonosis that has significantly impacted public health, livestock health and production, and food security over the last three decades across large regions of the African continent and the Arabian Peninsula. The potential for expansion of RVF outbreaks within and beyond the range of previous occurrence is unknown. Despite many large national and international epidemics, the landscape epidemiology of RVF remains obscure, particularly with respect to the ecological roles of wildlife reservoirs and surface water features. The current investigation modeled RVF risk throughout Africa and the Arabian Peninsula as a function of a suite of biotic and abiotic landscape features using machine learning methods. Intermittent wetland, wild Bovidae species richness and sheep density were associated with increased landscape suitability to RVF outbreaks. These results suggest the role of wildlife hosts and distinct hydrogeographic landscapes in RVF virus circulation and subsequent outbreaks may be underestimated. These results await validation by studies employing a deeper, field-based interrogation of potential wildlife hosts within high risk taxa.

  14. Reprint of "Epidemiology of brucellosis, Q Fever and Rift Valley Fever at the human and livestock interface in northern Côte d'Ivoire".

    Science.gov (United States)

    Kanouté, Youssouf B; Gragnon, Biégo G; Schindler, Christian; Bonfoh, Bassirou; Schelling, Esther

    2017-11-01

    Northern Côte d'Ivoire is the main livestock breeding zone and has the highest livestock cross-border movements in Côte d'Ivoire. The aim of this study was to provide updated epidemiological data on three neglected zoonotic diseases, namely brucellosis, Q Fever and Rift Valley Fever (RVF). We conducted three-stage cross-sectional cluster surveys in livestock and humans between 2012 and 2014 in a random selection of 63 villages and a sample of 633 cattle, 622 small ruminants and 88 people. We administered questionnaires to capture risk factors and performed serological tests including the Rose Bengal Plate Test (RBPT), Brucella spp. indirect and competitive ELISAs, Coxiella burnetii indirect ELISA and RVF competitive ELISA. The human seroprevalence for Brucella spp. was 5.3%. RBPT-positive small ruminants tested negative by the indirect ELISA. The seroprevalence of Brucella spp. in cattle adjusted for clustering was 4.6%. Cattle aged 5-8 years had higher odds of seropositivity (OR=3.5) than those aged ≤4years. The seropositivity in cattle was associated with having joint hygromas (OR=9), sharing the pastures with small ruminants (OR=5.8) and contact with pastoralist herds (OR=11.3). The seroprevalence of Q Fever was 13.9% in cattle, 9.4% in sheep and 12.4% in goats. The seroprevalence of RVF was 3.9% in cattle, 2.4% in sheep and 0% in goats. Seropositive ewes had greater odds (OR=4.7) of abortion than seronegative ones. In cattle, a shorter distance between the night pens and nearest permanent water bodies was a protective factor (OR=0.1). The study showed that the exposure to the three zoonoses is rather low in northern Côte d'Ivoire. Within a One Health approach, cost-benefit and cost-effectiveness of control measures should be assessed for an integrated control. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Analysis of surveillance systems in place in European Mediterranean countries for West Nile virus (WNV) and Rift Valley fever (RVF).

    Science.gov (United States)

    Cito, F; Narcisi, V; Danzetta, M L; Iannetti, S; Sabatino, D D; Bruno, R; Carvelli, A; Atzeni, M; Sauro, F; Calistri, P

    2013-11-01

    West Nile virus (WNV) and Rift Valley fever virus (RVFV) represent an important group of viral agents responsible for vector-borne zoonotic diseases constituting an emerging sanitary threat for the Mediterranean Basin and the neighbouring countries. WNV infection is present in several Mediterranean countries, whereas RVF has never been introduced into Europe, but it is considered a major threat for North African countries. Being vector-borne diseases, they cannot be prevented only through an animal trade control policy. Several approaches are used for the surveillance of WNV and RVFV. With the aim of assessing the surveillance systems in place in Mediterranean countries, two disease-specific questionnaires (WNV, RVFV) have been prepared and submitted to Public Health and Veterinary Authorities of six EU countries. This study presents the information gathered through the questionnaires and describes some critical points in the prevention and surveillance of these diseases as emerged by the answers received. © 2013 Blackwell Verlag GmbH.

  16. Rift Valley fever virus infection in African Buffalo (Syncerus caffer) herds in rural South Africa: Evidence of interepidemic transmission

    Science.gov (United States)

    LaBeaud, A.D.; Cross, P.C.; Getz, W.M.; Glinka, A.; King, C.H.

    2011-01-01

    Rift Valley fever virus (RVFV) is an emerging biodefense pathogen that poses significant threats to human and livestock health. To date, the interepidemic reservoirs of RVFV are not well defined. In a longitudinal survey of infectious diseases among African buffalo during 2000-2006, 550 buffalo were tested for antibodies against RVFV in 820 capture events in 302 georeferenced locations in Kruger National Park, South Africa. Overall, 115 buffalo (21%) were seropositive. Seroprevalence of RVFV was highest (32%) in the first study year, and decreased progressively in subsequent years, but had no detectable impact on survival. Nine (7%) of 126 resampled, initially seronegative animals seroconverted during periods outside any reported regional RVFV outbreaks. Seroconversions for RVFV were detected in significant temporal clusters during 2001-2003 and in 2004. These findings highlight the potential importance of wildlife as reservoirs for RVFV and interepidemic RVFV transmission in perpetuating regional RVFV transmission risk. Copyright ?? 2011 by The American Society of Tropical Medicine and Hygiene.

  17. Knowledge, attitudes and practices on Rift Valley fever among agro pastoral communities in Kongwa and Kilombero districts, Tanzania.

    Science.gov (United States)

    Shabani, Sasita S; Ezekiel, Mangi J; Mohamed, Mohamed; Moshiro, Candida S

    2015-08-21

    Rift valley fever (RVF) is a re-emerging viral vector-borne disease with rapid global socio-economic impact. A large RVF outbreak occurred in Tanzania in 2007 and affected more than half of the regions with high (47 %) case fatality rate. Little is known about RVF and its dynamics. A cross sectional study was conducted to assess the knowledge, attitudes and practices regarding RVF in Kongwa and Kilombero districts, Tanzania. We conducted a cross sectional survey among a randomly selected sample of individuals in 2011. We administered questionnaires to collect data on demographic characteristics, knowledge on symptoms, mode of transmission, prevention, attitudes and health seeking practices. A total of 463 community members participated in this study. The mean (±SD) age was 39.8 ± 14.4 years and 238 (51.4 %) were female. Majority of respondents had heard of RVF. However, only 8.8 % knew that mosquitoes were transmitting vectors. Male respondents were more likely to have greater knowledge about RVF. A small proportion mentioned clinical signs and symptoms of RVF in animals while 73.7 % mentioned unhealthy practices related to handling and consumption of dead animals. Thorough boiling of milk and cooking of meat were commonly mentioned as preventive measures for RVF. Majority (74.6 %) sought care for febrile illness at health facilities. Few (24.3 %) reported the use of protective gears to handle dead/sick animal while 15.5 % were consuming dead animals. Our study highlights the need to address the limited knowledge about RVF and promoting appropriate and timely health seeking practices. Rift valley fever outbreaks can be effectively managed with collaborative efforts of lay and professional communities with a shared perception that it poses a serious threat to public and animal health. The fact that this study was conducted in "high risk transmission areas" warrants further inquiry in other geographic regions with relatively low risk of RVF.

  18. The landscape-ecological units in the Planica valley, in the Julian Alps

    Directory of Open Access Journals (Sweden)

    Franc Lovrenčak

    2003-12-01

    Full Text Available Planica is a long glacial valley, situated on the northern side of the Julian Alps. During the Pleistocen its upper and middle part were transformed by a vast glacier, coming from under the Jalovec (2645 m and thus turned it into a typical U-sloped glacial valley. After the withdrawal of the glacier screes appeared. There lies a moraine in the middle part of the Planica valley, beginning in the southern part and extending to the north. Since such landforms, which serve as a basis for the development of soils, are of different age, the soils naturally belong to different periods in time, too. All that has contributed to the diversity of vegetation. Regarding the variety of land-forms, soils and vegetation, one can distinguish four main landscape-ecologic units in Planica, consisting of typical landforms, soils and vegetation.

  19. Choice of inbred rat strain impacts lethality and disease course after respiratory infection with Rift Valley Fever virus

    Directory of Open Access Journals (Sweden)

    Jacquelyn M. Bales

    2012-08-01

    Full Text Available Humans infected with Rift Valley Fever virus (RVFV generally recover after a febrile illness; however, a proportion of patients progress to a more severe clinical outcome such as hemorrhagic fever or meningoencephalitis. RVFV is naturally transmitted to livestock and humans by mosquito bites, but it is also infectious through inhalational exposure, making it a potential bioterror weapon. To better understand the disease caused by inhalation of RVFV, Wistar-Furth, ACI, or Lewis rats were exposed to experimental aerosols containing virulent RVFV. Wistar-Furth rats developed a rapidly progressing lethal hepatic disease after inhalational exposure; ACI rats were 100-fold less susceptible and developed fatal encephalitis after infection. Lewis rats, which do not succumb to parenteral inoculation with RVFV, developed fatal encephalitis after aerosol infection. RVFV was found in the liver, lung, spleen, heart, kidney and brain of Wistar Furth rats that succumbed after aerosol exposure. In contrast, RVFV was found only in the brains of ACI or Lewis rats that succumbed after aerosol exposure. Lewis rats that survived s.c. infection were not protected against subsequent re-challenge by aerosol exposure to the homologous virus. This is the first side-by-side comparison of the lethality and pathogenesis of RVFV in 3 rat strains after aerosol exposure and the first step towards developing a rodent model suitable for use under the FDA Animal Rule to test potential vaccines and therapeutics for aerosol exposure to RVFV.

  20. Choice of inbred rat strain impacts lethality and disease course after respiratory infection with Rift Valley Fever Virus

    Science.gov (United States)

    Bales, Jacquelyn M.; Powell, Diana S.; Bethel, Laura M.; Reed, Douglas S.; Hartman, Amy L.

    2012-01-01

    Humans infected with Rift Valley Fever Virus (RVFV) generally recover after a febrile illness; however, a proportion of patients progress to a more severe clinical outcome such as hemorrhagic fever or meningoencephalitis. RVFV is naturally transmitted to livestock and humans by mosquito bites, but it is also infectious through inhalational exposure, making it a potential bioterror weapon. To better understand the disease caused by inhalation of RVFV, Wistar-Furth, ACI, or Lewis rats were exposed to experimental aerosols containing virulent RVFV. Wistar-Furth rats developed a rapidly progressing lethal hepatic disease after inhalational exposure; ACI rats were 100-fold less susceptible and developed fatal encephalitis after infection. Lewis rats, which do not succumb to parenteral inoculation with RVFV, developed fatal encephalitis after aerosol infection. RVFV was found in the liver, lung, spleen, heart, kidney and brain of Wistar Furth rats that succumbed after aerosol exposure. In contrast, RVFV was found only in the brains of ACI or Lewis rats that succumbed after aerosol exposure. Lewis rats that survived s.c. infection were not protected against subsequent re-challenge by aerosol exposure to the homologous virus. This is the first side-by-side comparison of the lethality and pathogenesis of RVFV in three rat strains after aerosol exposure and the first step toward developing a rodent model suitable for use under the FDA Animal Rule to test potential vaccines and therapeutics for aerosol exposure to RVFV. PMID:22919694

  1. Association of symptoms and severity of rift valley fever with genetic polymorphisms in human innate immune pathways.

    Directory of Open Access Journals (Sweden)

    Amy G Hise

    2015-03-01

    Full Text Available Multiple recent outbreaks of Rift Valley Fever (RVF in Africa, Madagascar, and the Arabian Peninsula have resulted in significant morbidity, mortality, and financial loss due to related livestock epizootics. Presentation of human RVF varies from mild febrile illness to meningoencephalitis, hemorrhagic diathesis, and/or ophthalmitis with residual retinal scarring, but the determinants for severe disease are not understood. The aim of the present study was to identify human genes associated with RVF clinical disease in a high-risk population in Northeastern Province, Kenya.We conducted a cross-sectional survey among residents (N = 1,080; 1-85 yrs in 6 villages in the Sangailu Division of Ijara District. Participants completed questionnaires on past symptoms and exposures, physical exam, vision testing, and blood collection. Single nucleotide polymorphism (SNP genotyping was performed on a subset of individuals who reported past clinical symptoms consistent with RVF and unrelated subjects. Four symptom clusters were defined: meningoencephalitis, hemorrhagic fever, eye disease, and RVF-not otherwise specified. SNPs in 46 viral sensing and response genes were investigated. Association was analyzed between SNP genotype, serology and RVF symptom clusters. The meningoencephalitis symptom phenotype cluster among seropositive patients was associated with polymorphisms in DDX58/RIG-I and TLR8. Having three or more RVF-related symptoms was significantly associated with polymorphisms in TICAM1/TRIF, MAVS, IFNAR1 and DDX58/RIG-I. SNPs significantly associated with eye disease included three different polymorphisms TLR8 and hemorrhagic fever symptoms associated with TLR3, TLR7, TLR8 and MyD88.Of the 46 SNPs tested, TLR3, TLR7, TLR8, MyD88, TRIF, MAVS, and RIG-I were repeatedly associated with severe symptomatology, suggesting that these genes may have a robust association with RVFV-associated clinical outcomes. Studies of these and related genetic

  2. Ecology, biology and distribution of spotted-fever tick vectors in Brazil

    Directory of Open Access Journals (Sweden)

    Matias Pablo Juan Szabó

    2013-07-01

    Full Text Available Spotted-fever caused Rickettsia rickettsii infection is in Brazil the major tick-borne zoonotic disease. Recently a second and milder human rickettsiosis caused by an agent genetically related to R. parkeri was discovered in the country (Atlantic rainforest strain. Both diseases clearly have an ecological background linked to a few tick species and their environment. Capybaras (Hydrochoerys hydrochaeris and Amblyomma cajennense ticks in urban and rural areas close to water sources are the main and long known epidemiological feature behind R. rickettsii caused spotted fever. Unfortunately this ecological background seems to be increasing in the country and disease spreading may be foreseen. Metropolitan area of São Paulo, the most populous of the country, is embedded in Atlantic rainforest that harbors another important R. rickettsii vector, the tick Amblyomma aureolatum. Thus at the city-forest interface dogs carry infected ticks to human dwellings and human infection occurs. A role for R. rickettsii vectoring to humans of a third tick species, Rhipicephalus sanguineus in Brazil, has not been proven; however, there is circumstantial evidence for that. A Rickettsia parkeri-like strain was found in Amblyomma ovale ticks from Atlantic rainforest, and was shown to be responsible for a milder febrile human disease. Rickettsia-infected A. ovale ticks are known to be spread over large areas along the Atlantic coast of the country and diagnosis of human infection is increasing with awareness and proper diagnostic tools. In this review ecological features of the tick species mentioned, and that are important for Rickettsia transmission to humans, are updated and discussed. Specific knowledge gaps in the epidemiology of such diseases are highlighted to guide forthcoming research.

  3. Ecology and geography of hemorrhagic fever with renal syndrome in Changsha, China.

    Science.gov (United States)

    Xiao, Hong; Lin, Xiaoling; Gao, Lidong; Huang, Cunrui; Tian, Huaiyu; Li, Na; Qin, Jianxin; Zhu, Peijuan; Chen, Biyun; Zhang, Xixing; Zhao, Jian

    2013-07-03

    Hemorrhagic fever with renal syndrome (HFRS) is an important public health problem in mainland China. HFRS is particularly endemic in Changsha, the capital city of Hunan Province, with one of the highest incidences in China. The occurrence of HFRS is influenced by environmental factors. However, few studies have examined the relationship between environmental variation (such as land use changes and climate variations), rodents and HFRS occurrence. The purpose of this study is to predict the distribution of HFRS and identify the risk factors and relationship between HFRS occurrence and rodent hosts, combining ecological modeling with the Markov chain Monte Carlo approach. Ecological niche models (ENMs) were used to evaluate potential geographic distributions of rodent species by reconstructing details of their ecological niches in ecological dimensions, and projecting the results onto geography. The Genetic Algorithm for Rule-set Production was used to produce ENMs. Data were collected on HFRS cases in Changsha from 2005 to 2009, as well as national land survey data, surveillance data of rodents, meteorological data and normalized difference vegetation index (NDVI). The highest occurrence of HFRS was in districts with strong temperature seasonality, where elevation is below 200 m, mean annual temperature is around 17.5°C, and annual precipitation is below 1600 mm. Cultivated and urban lands in particular are associated with HFRS occurrence. Monthly NDVI values of areas predicted present is lower than areas predicted absent, with high seasonal variation. The number of HFRS cases was correlated with rodent density, and the incidence of HFRS cases in urban and forest areas was mainly associated with the density of Rattus norvegicus and Apodemus agrarius, respectively. Heterogeneity between different areas shows that HFRS occurrence is affected by the intensity of human activity, climate conditions, and landscape elements. Rodent density and species composition have

  4. Prediction, Assessment of the Rift Valley Fever Activity in East and Southern Africa 2006–2008 and Possible Vector Control Strategies

    OpenAIRE

    Anyamba, Assaf; Kenneth J Linthicum; Small, Jennifer; Britch, Seth C.; Pak, Edwin; de La Rocque, Stephane; Formenty, Pierre; Hightower, Allen W.; Robert F Breiman; Chretien, Jean-Paul; Compton J Tucker; Schnabel, David; Sang, Rosemary; Haagsma, Karl; Latham, Mark

    2010-01-01

    Historical outbreaks of Rift Valley fever (RVF) since the early 1950s have been associated with cyclical patterns of the El Niño/Southern Oscillation (ENSO) phenomenon, which results in elevated and widespread rainfall over the RVF endemic areas of Africa. Using satellite measurements of global and regional elevated sea surface temperatures, elevated rainfall, and satellite derived-normalized difference vegetation index data, we predicted with lead times of 2–4 months areas where outbreaks of...

  5. Planning for Rift Valley fever virus: use of geographical information systems to estimate the human health threat of white-tailed deer (Odocoileus virginianus)-related transmission

    OpenAIRE

    Sravan Kakani; Desirée LaBeaud, A.; King, Charles H.

    2010-01-01

    Rift Valley fever (RVF) virus is a mosquito-borne phlebovirus of the Bunyaviridae family that causes frequent outbreaks of severe animal and human disease in sub-Saharan Africa, Egypt and the Arabian Peninsula. Based on its many known competent vectors, its potential for transmission via aerosolization, and its progressive spread from East Africa to neighbouring regions, RVF is considered a high-priority, emerging health threat for humans, livestock and wildlife in all parts of the world. Int...

  6. Planning for Rift Valley fever virus: Use of GIS to estimate the human health threat of white-tailed deer (Odocoileus virginianus)-related transmission

    OpenAIRE

    Kakani, Sravan; LaBeaud, A. Desirée; King, Charles H.

    2010-01-01

    Rift Valley fever virus (RVFV) is a mosquito-borne phlebovirus of the Bunyaviridae family that causes frequent outbreaks of severe animal and human disease in sub-Saharan Africa, Egypt,and the Arabian Peninsula. Based on its many known competent vectors, its potential for transmission via aerosolization, and its progressive spread from East Africa to neighboring regions, RVFV is considered a high-priority, emerging health threat forhumans, livestock, and wildlife in all parts of the world. In...

  7. LANDSCAPE ECOLOGICAL METHOD TO STUDY AGRICULTURAL VEGETATION: SOME EXAMPLES FROM THE PO VALLEY

    Directory of Open Access Journals (Sweden)

    E. GIGLIO

    2006-01-01

    Full Text Available Vegetation is the most important landscape component, as regards to its ability to catch solar energy and to transform it, but also to shape the landscape, to structure the space, to create the fit environment for different animal species, to contribute to the maintenance of a correct metastability level for the landscape, etc. It is a biological system which acts under the constraints of the principles of the System Theory and owns the same properties of any other living system: so, it is a complex adaptive, hierarchical, dynamic, dissipative, self-organizing, self-transcendent, autocatalytic, self-maintaining system and follows the non-equilibrium thermodynamic. Its ecological state can be investigated through the comparison between “gathered data” (pathology and “normal data” (physiology for analogous types of vegetation. The Biological Integrated School of Landscape Ecology provides an integrated methodology to define ecological threshold limits of the different Agricultural Landscape types and applies to agricultural vegetation the specific part of the new methodology already tested to studying forests (the Landscape Biological Survey of Vegetation. Ecological quality, better and worst parameters, biological territorial capacity of vegetated corridors, agricultural field, poplar groves, orchards and woody remnant patches are investigated. Some examples from diverse agricultural landscapes of the Po Valley will be discussed. KEY WORDS: agricultural landscape, vegetation, landscape ecology, landscape health, Biological Integrated Landscape Ecology, Landscape Biological Survey of vegetation.

  8. An eco-health approach to Rift Valley Fever control among ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-08-17

    Aug 17, 2016 ... The team identified individual, community, and ecological risk factors that increase the vulnerability of pastoralist farmers and their livestock. Poor knowledge and awareness of the disease and poor livestock management practices increase the risks of disease. The project found that disease transmission ...

  9. Microbial ecology of extreme environments: Antarctic dry valley yeasts and growth in substrate-limited habitats

    Science.gov (United States)

    Vishniac, H. S.

    1982-01-01

    The success of the Antarctic Dry Valley yeasts presumeably results from adaptations to multiple stresses, to low temperatures and substrate-limitation as well as prolonged resting periods enforced by low water availability. Previous investigations have suggested that the crucial stress is substrate limitation. Specific adaptations may be pinpointed by comparing the physiology of the Cryptococcus vishniacii complex, the yeasts of the Tyrol Valley, with their congeners from other habitats. Progress was made in methods of isolation and definition of ecological niches, in the design of experiments in competition for limited substrate, and in establishing the relationships of the Cryptococcus vishniacii complex with other yeasts. In the course of investigating relationships, a new method for 25SrRNA homology was developed. For the first time it appears that 25SrRNA homology may reflect parallel or convergent evolution.

  10. "Ohio River valley fever" presenting as isolated granulomatous hepatitis: a case report.

    Science.gov (United States)

    Kibria, Rizwan; Bari, Khurram; Ali, Syed A; Barde, Christopher J

    2009-06-01

    Histoplasmosis is endemic to the midwestern and east central states in the United States near the Mississippi and the Ohio River valleys. Ninety-nine percent of patients exposed to histoplasmosis develop only subclinical infection. Liver involvement as a part of disseminated histoplasmosis is well known; however, isolated hepatic histoplasmosis without any other stigmata of dissemination is extremely rare and the literature is limited to only two case reports. We present a rare case of isolated granulomatous hepatitis due to histoplasmosis in a 35-year-old female with dermatomyositis receiving low-dose prednisone and methotrexate. There was no evidence of fungal dissemination elsewhere. High clinical suspicion is critical for early diagnosis and treatment.

  11. Planning for Rift Valley fever virus: use of geographical information systems to estimate the human health threat of white-tailed deer (Odocoileus virginianus)-related transmission.

    Science.gov (United States)

    Kakani, Sravan; LaBeaud, A Desirée; King, Charles H

    2010-11-01

    Rift Valley fever (RVF) virus is a mosquito-borne phlebovirus of the Bunyaviridae family that causes frequent outbreaks of severe animal and human disease in sub-Saharan Africa, Egypt and the Arabian Peninsula. Based on its many known competent vectors, its potential for transmission via aerosolization, and its progressive spread from East Africa to neighbouring regions, RVF is considered a high-priority, emerging health threat for humans, livestock and wildlife in all parts of the world. Introduction of West Nile virus to North America has shown the potential for "exotic" viral pathogens to become embedded in local ecological systems. While RVF is known to infect and amplify within domestic livestock, such as taurine cattle, sheep and goats, if RVF virus is accidentally or intentionally introduced into North America, an important unknown factor will be the role of local wildlife in the maintenance or propagation of virus transmission. We examined the potential impact of RVF transmission via white-tailed deer (Odocoileus virginianus) in a typical north-eastern United States urban-suburban landscape, where livestock are rare but where these potentially susceptible, ungulate wildlife are highly abundant. Model results, based on overlap of mosquito, human and projected deer densities, indicate that a significant proportion (497/1186 km(2), i.e. 42%) of the urban and peri-urban landscape could be affected by RVF transmission during the late summer months. Deer population losses, either by intervention for herd reduction or by RVF-related mortality, would substantially reduce these likely transmission zones to 53.1 km(2), i.e. by 89%.

  12. Planning for Rift Valley fever virus: Use of GIS to estimate the human health threat of white-tailed deer (Odocoileus virginianus)-related transmission

    Science.gov (United States)

    Kakani, Sravan; LaBeaud, A. Desirée; King, Charles H.

    2011-01-01

    Rift Valley fever virus (RVFV) is a mosquito-borne phlebovirus of the Bunyaviridae family that causes frequent outbreaks of severe animal and human disease in sub-Saharan Africa, Egypt,and the Arabian Peninsula. Based on its many known competent vectors, its potential for transmission via aerosolization, and its progressive spread from East Africa to neighboring regions, RVFV is considered a high-priority, emerging health threat forhumans, livestock, and wildlife in all parts of the world. Introduction of West Nile virus to North America has shown the potential for ‘exotic’ viral pathogens to become embedded in local ecological systems. While RVFV is known to infect and amplify within domestic livestock, such as taurine cattle, sheep, and goats, if RVFV is accidentally or intentionally introduced into North America, an important unknown factor will be the role of local wildlife in the maintenance or propagation of virus transmission. We examined the potential impact of RVFV transmission via white-tailed deer (Odocoileus virginianus)in a typical northeastern United States urban-suburban landscape, where livestock are rare, but these potentially susceptible ungulate wildlife are highly abundant. Model results, based on overlap of mosquito, human, and projected deer densities, indicate that a significant proportion (497/1186 km2, or 42 %) of the urban and peri-urban landscape could be affected by RVFV transmission during the late summermonths. Deer population losses, either by intervention for herd reduction or by RVFV-related mortality, would substantially reduce these likely transmission zones to 53.1 km2, orby 89%. PMID:21080319

  13. Planning for Rift Valley fever virus: use of geographical information systems to estimate the human health threat of white-tailed deer (Odocoileus virginianus-related transmission

    Directory of Open Access Journals (Sweden)

    Sravan Kakani

    2010-11-01

    Full Text Available Rift Valley fever (RVF virus is a mosquito-borne phlebovirus of the Bunyaviridae family that causes frequent outbreaks of severe animal and human disease in sub-Saharan Africa, Egypt and the Arabian Peninsula. Based on its many known competent vectors, its potential for transmission via aerosolization, and its progressive spread from East Africa to neighbouring regions, RVF is considered a high-priority, emerging health threat for humans, livestock and wildlife in all parts of the world. Introduction of West Nile virus to North America has shown the potential for “exotic” viral pathogens to become embedded in local ecological systems. While RVF is known to infect and amplify within domestic livestock, such as taurine cattle, sheep and goats, if RVF virus is accidentally or intentionally introduced into North America, an important unknown factor will be the role of local wildlife in the maintenance or propagation of virus transmission. We examined the potential impact of RVF transmission via white-tailed deer (Odocoileus virginianus in a typical north-eastern United States urban-suburban landscape, where livestock are rare but where these potentially susceptible, ungulate wildlife are highly abundant. Model results, based on overlap of mosquito, human and projected deer densities, indicate that a significant proportion (497/1186 km2, i.e. 42% of the urban and peri-urban landscape could be affected by RVF transmission during the late summer months. Deer population losses, either by intervention for herd reduction or by RVF-related mortality, would substantially reduce these likely transmission zones to 53.1 km2, i.e. by 89%.

  14. Rift valley fever virus infection of human cells and insect hosts is promoted by protein kinase C epsilon.

    Directory of Open Access Journals (Sweden)

    Claire Marie Filone

    2010-11-01

    Full Text Available As an arthropod-borne human pathogen, Rift Valley fever virus (RVFV cycles between an insect vector and mammalian hosts. Little is known about the cellular requirements for infection in either host. Here we developed a tissue culture model for RVFV infection of human and insect cells that is amenable to high-throughput screening. Using this approach we screened a library of 1280 small molecules with pharmacologically defined activities and identified 59 drugs that inhibited RVFV infection with 15 inhibiting RVFV replication in both human and insect cells. Amongst the 15 inhibitors that blocked infection in both hosts was a subset that inhibits protein kinase C. Further studies found that infection is dependent upon the novel protein kinase C isozyme epsilon (PKCε in both human and insect cells as well as in adult flies. Altogether, these data show that inhibition of cellular factors required for early steps in the infection cycle including PKCε can block RVFV infection, and may represent a starting point for the development of anti-RVFV therapeutics.

  15. A Rift Valley fever risk surveillance system for Africa using remotely sensed data: potential for use on other continents.

    Science.gov (United States)

    Linthicum, Kenneth J; Anyamba, Assaf; Britch, Seth C; Chretien, Jean-Paul; Erickson, Ralph L; Small, Jennifer; Tucker, Compton J; Bennett, Kristine E; Mayer, Richard T; Schmidtmann, Edward T; Andreadis, Theodore G; Anderson, John F; Wilson, William C; Freier, Jerome E; James, Angela M; Miller, Ryan S; Drolet, Barbara S; Miller, Scott N; Tedrow, Christy A; Bailey, Charles L; Strickman, Daniel A; Barnard, Donald R; Clark, Gary G; Zou, Li

    2007-01-01

    The authors developed a monitoring and risk mapping system using normalized difference vegetation index (NDVI) times series data derived from the advanced very high resolution radiometer (AVHRR) instrument on polar orbiting national oceanographic and atmospheric administration (NOAA) satellites to map areas with a potential for a Rift Valley fever (RVF) outbreaks in sub-Saharan Africa. This system is potentially an important tool for local, national and international organisations involved in the prevention and control of animal and human disease, permitting focused and timely implementation of disease control strategies several months before an outbreak. We are currently developing a geographic information system (GIS)-based remotely sensed early warning system for potential RVF vectors in the United States. Forecasts of the potential emergence of mosquito vectors will be disseminated throughout the United States, providing several months' warning in advance of potentially elevated mosquito populations. This would allow timely, targeted implementation of mosquito control, animal quarantine and vaccine strategies to reduce or prevent animal and human disease.

  16. Rift Valley fever dynamics in Senegal: a project for pro-active adaptation and improvement of livestock raising management.

    Science.gov (United States)

    Lafaye, Murielle; Sall, Baba; Ndiaye, Youssou; Vignolles, Cecile; Tourre, Yves M; Borchi, Franc Ois; Soubeyroux, Jean-Michel; Diallo, Mawlouth; Dia, Ibrahima; Ba, Yamar; Faye, Abdoulaye; Ba, Taibou; Ka, Alioune; Ndione, Jacques-André; Gauthier, Hélène; Lacaux, Jean-Pierre

    2013-11-01

    The multi-disciplinary French project "Adaptation à la Fiévre de la Vallée du Rift" (AdaptFVR) has concluded a 10-year constructive interaction between many scientists/partners involved with the Rift Valley fever (RVF) dynamics in Senegal. The three targeted objectives reached were (i) to produce--in near real-time--validated risk maps for parked livestock exposed to RVF mosquitoes/vectors bites; (ii) to assess the impacts on RVF vectors from climate variability at different time-scales including climate change; and (iii) to isolate processes improving local livestock management and animal health. Based on these results, concrete, pro-active adaptive actions were taken on site, which led to the establishment of a RVF early warning system (RVFews). Bulletins were released in a timely fashion during the project, tested and validated in close collaboration with the local populations, i.e. the primary users. Among the strategic, adaptive methods developed, conducted and evaluated in terms of cost/benefit analyses are the larvicide campaigns and the coupled bio-mathematical (hydrological and entomological) model technologies, which are being transferred to the staff of the "Centre de Suivi Ecologique" (CSE) in Dakar during 2013. Based on the results from the AdaptFVR project, other projects with similar conceptual and modelling approaches are currently being implemented, e.g. for urban and rural malaria and dengue in the French Antilles.

  17. Emerging vector-borne diseases in dromedaries in Tunisia: West Nile, bluetongue, epizootic haemorrhagic disease and Rift Valley fever

    Directory of Open Access Journals (Sweden)

    Thameur B. Hassine

    2017-01-01

    Full Text Available 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.

  18. Reconstruction of Rift Valley fever transmission dynamics in Madagascar: estimation of force of infection from seroprevalence surveys using Bayesian modelling.

    Science.gov (United States)

    Olive, Marie-Marie; Grosbois, Vladimir; Tran, Annelise; Nomenjanahary, Lalaina Arivony; Rakotoarinoro, Mihaja; Andriamandimby, Soa-Fy; Rogier, Christophe; Heraud, Jean-Michel; Chevalier, Veronique

    2017-01-04

    The force of infection (FOI) is one of the key parameters describing the dynamics of transmission of vector-borne diseases. Following the occurrence of two major outbreaks of Rift Valley fever (RVF) in Madagascar in 1990-91 and 2008-09, recent studies suggest that the pattern of RVF virus (RVFV) transmission differed among the four main eco-regions (East, Highlands, North-West and South-West). Using Bayesian hierarchical models fitted to serological data from cattle of known age collected during two surveys (2008 and 2014), we estimated RVF FOI and described its variations over time and space in Madagascar. We show that the patterns of RVFV transmission strongly differed among the eco-regions. In the North-West and Highlands regions, these patterns were synchronous with a high intensity in mid-2007/mid-2008. In the East and South-West, the peaks of transmission were later, between mid-2008 and mid-2010. In the warm and humid northwestern eco-region favorable to mosquito populations, RVFV is probably transmitted all year-long at low-level during inter-epizootic period allowing its maintenance and being regularly introduced in the Highlands through ruminant trade. The RVF surveillance of animals of the northwestern region could be used as an early warning indicator of an increased risk of RVF outbreak in Madagascar.

  19. Rift Valley fever dynamics in Senegal: a project for pro-active adaptation and improvement of livestock raising management

    Directory of Open Access Journals (Sweden)

    Murielle Lafaye

    2013-11-01

    Full Text Available The multi-disciplinary French project “Adaptation à la Fièvre de la Vallée du Rift” (AdaptFVR has concluded a 10-year constructive interaction between many scientists/partners involved with the Rift Valley fever (RVF dynamics in Senegal. The three targeted objectives reached were (i to produce - in near real-time - validated risk maps for parked livestock exposed to RVF mosquitoes/vectors bites; (ii to assess the impacts on RVF vectors from climate variability at different time-scales including climate change; and (iii to isolate processes improving local livestock management and animal health. Based on these results, concrete, pro-active adaptive actions were taken on site, which led to the establishment of a RVF early warning system (RVFews. Bulletins were released in a timely fashion during the project, tested and validated in close collaboration with the local populations, i.e. the primary users. Among the strategic, adaptive methods developed, conducted and evaluated in terms of cost/benefit analyses are the larvicide campaigns and the coupled bio-mathematical (hydrological and entomological model technologies, which are being transferred to the staff of the “Centre de Suivi Ecologique” (CSE in Dakar during 2013. Based on the results from the AdaptFVR project, other projects with similar conceptual and modelling approaches are currently being implemented, e.g. for urban and rural malaria and dengue in the French Antilles.

  20. Role of Culex and Anopheles mosquito species as potential vectors of rift valley fever virus in Sudan outbreak, 2007

    Directory of Open Access Journals (Sweden)

    Galal Fatma H

    2010-03-01

    Full Text Available Abstract Background Rift Valley fever (RVF is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. Methods Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species. Results A total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7% in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2% in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by ≥ 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between

  1. The sero-epidemiology of Rift Valley fever in people in the Lake Victoria Basin of western Kenya

    Science.gov (United States)

    Grossi-Soyster, Elysse Noel; de Glanville, William Anson; Thomas, Lian Francesca; Kariuki, Samuel; Bronsvoort, Barend Mark de Clare; Wamae, Claire Njeri; LaBeaud, Angelle Desiree; Fèvre, Eric Maurice

    2017-01-01

    Rift Valley fever virus (RVFV) is a zoonotic arbovirus affecting livestock and people. This study was conducted in western Kenya where RVFV outbreaks have not previously been reported. The aims were to document the seroprevalence and risk factors for RVFV antibodies in a community-based sample from western Kenya and compare this with slaughterhouse workers in the same region who are considered a high-risk group for RVFV exposure. The study was conducted in western Kenya between July 2010 and November 2012. Individuals were recruited from randomly selected homesteads and a census of slaughterhouses. Structured questionnaire tools were used to collect information on demographic data, health, and risk factors for zoonotic disease exposure. Indirect ELISA on serum samples determined seropositivity to RVFV. Risk factor analysis for RVFV seropositivity was conducted using multi-level logistic regression. A total of 1861 individuals were sampled in 384 homesteads. The seroprevalence of RVFV in the community was 0.8% (95% CI 0.5–1.3). The variables significantly associated with RVFV seropositivity in the community were increasing age (OR 1.2; 95% CI 1.1–1.4, pslaughterhouse workers were sampled in 84 ruminant slaughterhouses. The seroprevalence of RVFV in slaughterhouse workers was 2.5% (95% CI 1.5–4.2). Being the slaughterman, the person who cuts the animal’s throat (OR 3.5; 95% CI 1.0–12.1, p = 0.047), was significantly associated with RVFV seropositivity. This study investigated and compared the epidemiology of RVFV between community members and slaughterhouse workers in western Kenya. The data demonstrate that slaughtering animals is a risk factor for RVFV seropositivity and that slaughterhouse workers are a high-risk group for RVFV seropositivity in this environment. These risk factors have been previously reported in other studies providing further evidence for RVFV circulation in western Kenya. PMID:28686589

  2. A Systematic Scoping Study of the Socio-Economic Impact of Rift Valley Fever: Research Gaps and Needs.

    Science.gov (United States)

    Peyre, M; Chevalier, V; Abdo-Salem, S; Velthuis, A; Antoine-Moussiaux, N; Thiry, E; Roger, F

    2015-08-01

    Rift Valley fever (RVF) is a severe mosquito-borne disease affecting humans and domestic ruminants. RVF virus has been reported in most African countries, as well as in the Arabic Peninsula. This paper reviews the different types of socio-economic impact induced by RVF disease and the attempts to evaluate them. Of the 52 papers selected for this review, 13 types of socio-economic impact were identified according to the sector impacted, the level and temporal scale of the impact. RVF has a dramatic impact on producers and livestock industries, affecting public and animal health, food security and the livelihood of the pastoralist communities. RVF also has an impact on international trade and other agro-industries. The risk of introducing RVF into disease-free countries via the importation of an infected animal or mosquito is real, and the consequent restriction of access to export markets may induce dramatic economic consequences for national and local economies. Despite the important threat of RVF, few studies have been conducted to assess the socio-economic impact of the disease. The 17 studies identified for quantitative analysis in this review relied only on partial cost analysis, with limited reference to mid- and long-term impact, public health or risk mitigation measures. However, the estimated impacts were high (ranging from $5 to $470 million USD losses). To reduce the impact of RVF, early detection and rapid response should be implemented. Comprehensive disease impact studies are required to provide decision-makers with science-based information on the best intervention measure to implement ensuring efficient resource allocation. Through the analysis of RVF socio-economic impact, this scoping study proposes insights into the mechanisms underpinning its often-underestimated importance. This study highlights the need for comparative socio-economic studies to help decision-makers with their choices related to RVF disease management. © 2014 The Authors

  3. Single-dose immunization with virus replicon particles confers rapid robust protection against Rift Valley fever virus challenge.

    Science.gov (United States)

    Dodd, Kimberly A; Bird, Brian H; Metcalfe, Maureen G; Nichol, Stuart T; Albariño, César G

    2012-04-01

    Rift Valley fever virus (RVFV) causes outbreaks of severe disease in people and livestock throughout Africa and the Arabian Peninsula. The potential for RVFV introduction outside the area of endemicity highlights the need for fast-acting, safe, and efficacious vaccines. Here, we demonstrate a robust system for the reverse genetics generation of a RVF virus replicon particle (VRP(RVF)) vaccine candidate. Using a mouse model, we show that VRP(RVF) immunization provides the optimal balance of safety and single-dose robust efficacy. VRP(RVF) can actively synthesize viral RNA and proteins but lacks structural glycoprotein genes, preventing spread within immunized individuals and reducing the risk of vaccine-induced pathogenicity. VRP(RVF) proved to be completely safe following intracranial inoculation of suckling mice, a stringent test of vaccine safety. Single-dose subcutaneous immunization with VRP(RVF), although it is highly attenuated, completely protected mice against a virulent RVFV challenge dose which was 100,000-fold greater than the 50% lethal dose (LD(50)). Robust protection from lethal challenge was observed by 24 h postvaccination, with 100% protection induced in as little as 96 h. We show that a single subcutaneous VRP(RVF) immunization initiated a systemic antiviral state followed by an enhanced adaptive response. These data contrast sharply with the much-reduced survivability and immune responses observed among animals immunized with nonreplicating viral particles, indicating that replication, even if confined to the initially infected cells, contributes substantially to protective efficacy at early and late time points postimmunization. These data demonstrate that replicon vaccines successfully bridge the gap between safety and efficacy and provide insights into the kinetics of antiviral protection from RVFV infection.

  4. Tissue tropism and target cells of NSs-deleted rift valley fever virus in live immunodeficient mice.

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    Céline Gommet

    2011-12-01

    Full Text Available BACKGROUND: Rift Valley fever virus (RVFV causes disease in livestock and humans. It can be transmitted by mosquitoes, inhalation or physical contact with the body fluids of infected animals. Severe clinical cases are characterized by acute hepatitis with hemorrhage, meningoencephalitis and/or retinitis. The dynamics of RVFV infection and the cell types infected in vivo are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: RVFV strains expressing humanized Renilla luciferase (hRLuc or green fluorescent protein (GFP were generated and inoculated to susceptible Ifnar1-deficient mice. We investigated the tissue tropism in these mice and the nature of the target cells in vivo using whole-organ imaging and flow cytometry. After intraperitoneal inoculation, hRLuc signal was observed primarily in the thymus, spleen and liver. Macrophages infiltrating various tissues, in particular the adipose tissue surrounding the pancreas also expressed the virus. The liver rapidly turned into the major luminescent organ and the mice succumbed to severe hepatitis. The brain remained weakly luminescent throughout infection. FACS analysis in RVFV-GFP-infected mice showed that the macrophages, dendritic cells and granulocytes were main target cells for RVFV. The crucial role of cells of the monocyte/macrophage/dendritic lineage during RVFV infection was confirmed by the slower viral dissemination, decrease in RVFV titers in blood, and prolonged survival of macrophage- and dendritic cell-depleted mice following treatment with clodronate liposomes. Upon dermal and nasal inoculations, the viral dissemination was primarily observed in the lymph node draining the injected ear and in the lungs respectively, with a significant increase in survival time. CONCLUSIONS/SIGNIFICANCE: These findings reveal the high levels of phagocytic cells harboring RVFV during viral infection in Ifnar1-deficient mice. They demonstrate that bioluminescent and fluorescent viruses can shed new

  5. Integrated Analysis of Environment, Cattle and Human Serological Data: Risks and Mechanisms of Transmission of Rift Valley Fever in Madagascar.

    Science.gov (United States)

    Olive, Marie-Marie; Chevalier, Véronique; Grosbois, Vladimir; Tran, Annelise; Andriamandimby, Soa-Fy; Durand, Benoit; Ravalohery, Jean-Pierre; Andriamamonjy, Seta; Rakotomanana, Fanjasoa; Rogier, Christophe; Heraud, Jean-Michel

    2016-07-01

    Rift Valley fever (RVF) is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008-2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i) to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii) to identify human behaviors favoring human infections in Malagasy contexts. First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA). Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human) as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior) as explanatory variables. Cattle and human seroprevalence rates were positively associated to humid environments (ptransmission in cattle. Our integrated approach analyzing environmental, cattle and human datasets allow us to bring new insight on RVF transmission patterns in Madagascar. The association between cattle seroprevalence, humid environments and high cattle density suggests that concomitant vectorial and direct transmissions are critical to maintain RVF enzootic transmission. Additionally, in the at-risk humid environment of the western, north-western and the eastern-coast areas, suitable to Culex and Anopheles mosquitoes, vectorial transmission probably occurs in both cattle and human. The relative contribution of vectorial or direct transmissions could be further assessed by mathematic modelling.

  6. Identification of suitable areas for the occurrence of Rift Valley fever outbreaks in Spain using a multiple criteria decision framework.

    Science.gov (United States)

    Sánchez-Vizcaíno, Fernando; Martínez-López, Beatriz; Sánchez-Vizcaíno, José Manuel

    2013-07-26

    Rift Valley fever (RVF) is a mosquito-borne viral disease that may produce a considerable impact on the economy in affected countries. In the last decades, the geographic distribution of RVF virus has increased including most of the countries in Africa, Arabia Saudi and Yemen. This situation has raised the concerns regarding its potential introduction in the European Union (EU) countries where the high number of susceptible species and competent vectors may contribute to the spread of the disease and challenge its rapid control. Thus, the identification of the areas and time periods with highest suitability for RVF outbreak occurrence would be useful for improving the early detection and rapid response of the disease into free countries. The objective of this study was to identify suitable areas for the occurrence of RVF outbreaks in Spain using a multiple criteria decision making model based on weighted linear combination of factors in geographical information systems (GIS). To the best of the author's knowledge this is the first comprehensive GIS-based framework that provides risk maps for RVF suitability in an EU country. Spanish zones with the highest suitability for RVF were concentrated in the regions of Extremadura, south-western Castile and Leon, eastern Galicia, Asturias, Cantabria, Basque Country, northern-central and southern region of Andalusia and in the Balearic Islands. October and May were the most suitable months for RVF outbreak occurrence. Methods and results presented here may be useful to target risk-based surveillance strategies and to more cost-effectively control potential RVFV incursions into Spain. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. TerraSAR-X high-resolution radar remote sensing: an operational warning system for Rift Valley fever risk

    Directory of Open Access Journals (Sweden)

    Cécile Vignolles

    2010-11-01

    Full Text Available In the vicinity of the Barkedji village (in the Ferlo region of Senegal, the abundance and aggressiveness of the vector mosquitoes for Rift Valley fever (RVF are strongly linked to rainfall events and associated ponds dynamics. Initially, these results were obtained from spectral analysis of high-resolution (~10 m Spot-5 images, but, as a part of the French AdaptFVR project, identification of the free water dynamics within ponds was made with the new high-resolution (down to 3-meter pixels, Synthetic Aperture Radar satellite (TerraSAR-X produced by Infoterra GmbH, Friedrichshafen/Potsdam, Germany. During summer 2008, within a 30 x 50 km radar image, it was found that identified free water fell well within the footprints of ponds localized by optical data (i.e. Spot-5 images, which increased the confidence in this new and complementary remote sensing technique. Moreover, by using near real-time rainfall data from the Tropical Rainfall Measuring Mission (TRMM, NASA/JAXA joint mission, the filling-up and flushingout rates of the ponds can be accurately determined. The latter allows for a precise, spatio-temporal mapping of the zones potentially occupied by mosquitoes capable of revealing the variability of pond surfaces. The risk for RVF infection of gathered bovines and small ruminants (~1 park/km2 can thus be assessed. This new operational approach (which is independent of weather conditions is an important development in the mapping of risk components (i.e. hazards plus vulnerability related to RVF transmission during the summer monsoon, thus contributing to a RVF early warning system.

  8. TerraSAR-X high-resolution radar remote sensing: an operational warning system for Rift Valley fever risk.

    Science.gov (United States)

    Vignolles, Cécile; Tourre, Yves M; Mora, Oscar; Imanache, Laurent; Lafaye, Murielle

    2010-11-01

    In the vicinity of the Barkedji village (in the Ferlo region of Senegal), the abundance and aggressiveness of the vector mosquitoes for Rift Valley fever (RVF) are strongly linked to rainfall events and associated ponds dynamics. Initially, these results were obtained from spectral analysis of high-resolution (~10 m) Spot-5 images, but, as a part of the French AdaptFVR project, identification of the free water dynamics within ponds was made with the new high-resolution (down to 3-meter pixels), Synthetic Aperture Radar satellite (TerraSAR-X) produced by Infoterra GmbH, Friedrichshafen/Potsdam, Germany. During summer 2008, within a 30 x 50 km radar image, it was found that identified free water fell well within the footprints of ponds localized by optical data (i.e. Spot-5 images), which increased the confidence in this new and complementary remote sensing technique. Moreover, by using near real-time rainfall data from the Tropical Rainfall Measuring Mission (TRMM), NASA/JAXA joint mission, the filling-up and flushing-out rates of the ponds can be accurately determined. The latter allows for a precise, spatio-temporal mapping of the zones potentially occupied by mosquitoes capable of revealing the variability of pond surfaces. The risk for RVF infection of gathered bovines and small ruminants (~1 park/km(2)) can thus be assessed. This new operational approach (which is independent of weather conditions) is an important development in the mapping of risk components (i.e. hazards plus vulnerability) related to RVF transmission during the summer monsoon, thus contributing to a RVF early warning system.

  9. Local Population Structure and Patterns of Western Hemisphere Dispersal for Coccidioides spp., the Fungal Cause of Valley Fever

    Directory of Open Access Journals (Sweden)

    David M. Engelthaler

    2016-04-01

    Full Text Available Coccidioidomycosis (or valley fever is a fungal disease with high morbidity and mortality that affects tens of thousands of people each year. This infection is caused by two sibling species, Coccidioides immitis and C. posadasii, which are endemic to specific arid locales throughout the Western Hemisphere, particularly the desert southwest of the United States. Recent epidemiological and population genetic data suggest that the geographic range of coccidioidomycosis is expanding, as new endemic clusters have been identified in the state of Washington, well outside the established endemic range. The genetic mechanisms and epidemiological consequences of this expansion are unknown and require better understanding of the population structure and evolutionary history of these pathogens. Here we performed multiple phylogenetic inference and population genomics analyses of 68 new and 18 previously published genomes. The results provide evidence of substantial population structure in C. posadasii and demonstrate the presence of distinct geographic clades in central and southern Arizona as well as dispersed populations in Texas, Mexico, South America, and Central America. Although a smaller number of C. immitis strains were included in the analyses, some evidence of phylogeographic structure was also detected in this species, which has been historically limited to California and Baja, Mexico. Bayesian analyses indicated that C. posadasii is the more ancient of the two species and that Arizona contains the most diverse subpopulations. We propose a southern Arizona-northern Mexico origin for C. posadasii and describe a pathway for dispersal and distribution out of this region.

  10. Integrated Analysis of Environment, Cattle and Human Serological Data: Risks and Mechanisms of Transmission of Rift Valley Fever in Madagascar.

    Directory of Open Access Journals (Sweden)

    Marie-Marie Olive

    2016-07-01

    Full Text Available Rift Valley fever (RVF is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008-2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii to identify human behaviors favoring human infections in Malagasy contexts.First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA. Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior as explanatory variables. Cattle and human seroprevalence rates were positively associated to humid environments (p<0.001. Areas with high cattle density were at risk (p<0.01; OR = 2.6. Furthermore, our analysis showed that frequent contact with raw milk contributed to explain human infection (OR = 1.6. Finally, our study highlighted the eastern-coast, western and north-western parts as high-risk areas for RVF transmission in cattle.Our integrated approach analyzing environmental, cattle and human datasets allow us to bring new insight on RVF transmission patterns in Madagascar. The association between cattle seroprevalence, humid environments and high cattle density suggests that concomitant vectorial and direct transmissions are critical to maintain RVF enzootic transmission. Additionally, in the at-risk humid environment of the western, north-western and the eastern-coast areas, suitable to Culex and Anopheles mosquitoes, vectorial transmission probably occurs in both cattle and human. The relative contribution

  11. Reverse-phase phosphoproteome analysis of signaling pathways induced by Rift valley fever virus in human small airway epithelial cells.

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    Taissia G Popova

    Full Text Available Rift valley fever virus (RVFV infection is an emerging zoonotic disease endemic in many countries of sub-Saharan Africa and in Egypt. In this study we show that human small airway epithelial cells are highly susceptible to RVFV virulent strain ZH-501 and the attenuated strain MP-12. We used the reverse-phase protein arrays technology to identify phosphoprotein signaling pathways modulated during infection of cultured airway epithelium. ZH-501 infection induced activation of MAP kinases (p38, JNK and ERK and downstream transcriptional factors [STAT1 (Y701, ATF2 (T69/71, MSK1 (S360 and CREB (S133]. NF-κB phosphorylation was also increased. Activation of p53 (S15, S46 correlated with the increased levels of cleaved effector caspase-3, -6 and -7, indicating activation of the extrinsic apoptotic pathway. RVFV infection downregulated phosphorylation of a major anti-apoptotic regulator of survival pathways, AKT (S473, along with phosphorylation of FOX 01/03 (T24/31 which controls cell cycle arrest downstream from AKT. Consistent with this, the level of apoptosis inhibitor XIAP was decreased. However, the intrinsic apoptotic pathway marker, caspase-9, demonstrated only a marginal activation accompanied by an increased level of the inhibitor of apoptosome formation, HSP27. Concentration of the autophagy marker, LC3B, which often accompanies the pro-survival signaling, was decreased. Cumulatively, our analysis of RVFV infection in lung epithelium indicated a viral strategy directed toward the control of cell apoptosis through a number of transcriptional factors. Analyses of MP-12 titers in challenged cells in the presence of MAPK inhibitors indicated that activation of p38 represents a protective cell response while ERK activation controls viral replication.

  12. Valley fever: finding new places for an old disease: Coccidioides immitis found in Washington State soil associated with recent human infection.

    Science.gov (United States)

    Litvintseva, Anastasia P; Marsden-Haug, Nicola; Hurst, Steven; Hill, Heather; Gade, Lalitha; Driebe, Elizabeth M; Ralston, Cindy; Roe, Chandler; Barker, Bridget M; Goldoft, Marcia; Keim, Paul; Wohrle, Ron; Thompson, George R; Engelthaler, David M; Brandt, Mary E; Chiller, Tom

    2015-01-01

    We used real-time polymerase chain reaction and culture to demonstrate persistent colonization of soils by Coccidioides immitis, an agent of valley fever, in Washington State linked to recent human infections and located outside the endemic range. Whole-genome sequencing confirmed genetic identity between isolates from soil and one of the case-patients. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  13. Evaluation of the Efficacy, Potential for Vector Transmission, and Duration of Immunity of MP-12, an Attenuated Rift Valley Fever Virus Vaccine Candidate, in Sheep

    Science.gov (United States)

    2015-08-01

    pathogen by the National Institute for Allergy and Infectious Diseases and is dual listed as a U.S. Department of Agriculture (USDA) select agent due to...12 serial passages of the wild-type ZH548 strain of RVFV in the presence of a chemical mutagen (22) and selected based on attenuation of virulence in...1743-422X-8-532. 22. Caplen H, Peters CJ, Bishop DH. 1985. Mutagen -directed attenua- tion of Rift Valley fever virus as a method for vaccine

  14. Balancing lake ecological condition and agriculture irrigation needs in the Mississippi Alluvial Valley

    Science.gov (United States)

    Miranda, Leandro E.; Omer, A.R.; Killgore, K.J.

    2017-01-01

    The Mississippi Alluvial Valley includes hundreds of floodplain lakes that support unique fish assemblages and high biodiversity. Irrigation practices in the valley have lowered the water table, increasing the cost of pumping water, and necessitating the use of floodplain lakes as a source of water for irrigation. This development has prompted the need to regulate water withdrawals to protect aquatic resources, but it is unknown how much water can be withdrawn from lakes before ecological integrity is compromised. To estimate withdrawal limits, we examined descriptors of lake water quality (i.e., total nitrogen, total phosphorus, turbidity, Secchi visibility, chlorophyll-a) and fish assemblages (species richness, diversity, composition) relative to maximum depth in 59 floodplain lakes. Change-point regression analysis was applied to identify critical depths at which the relationships between depth and lake descriptors exhibited a rapid shift in slope, suggesting possible thresholds. All our water quality and fish assemblage descriptors showed rapid changes relative to depth near 1.2–2.0 m maximum depth. This threshold span may help inform regulatory decisions about water withdrawal limits. Alternatives to explain the triggers of the observed threshold span are considered.

  15. Application of knowledge-driven spatial modelling approaches and uncertainty management to a study of Rift Valley fever in Africa

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    Pfeiffer Dirk U

    2006-12-01

    Full Text Available Abstract Background There are few studies that have investigated uncertainties surrounding the scientific community's knowledge of the geographical distribution of major animal diseases. This is particularly relevant to Rift Valley fever (RVF, a zoonotic disease causing destructive outbreaks in livestock and man, as the geographical range of the disease is widening to involve previously unaffected regions. In the current study we investigate the application of methods developed in the decision sciences: multiple criteria decision making using weighted linear combination and ordered weighted averages, and Dempster-Shafer theory, implemented within the geographical information system IDRISI, to obtain a greater understanding of uncertainty related to the geographical distribution of RVF. The focus is on presenting alternate methods where extensive field data are not available and traditional, model-based approaches to disease mapping are impossible to conduct. Results Using a compensatory multiple criteria decision making model based on weighted linear combination, most of sub-Saharan Africa was suitable for endemic circulation of RVF. In contrast, areas where rivers and lakes traversed semi-arid regions, such as those bordering the Sahara, were highly suitable for RVF epidemics and wet, tropical areas of central Africa had low suitability. Using a moderately non-compensatory model based on ordered weighted averages, the areas considered suitable for endemic and epidemic RVF were more restricted. Varying the relative weights of the different factors in the models did not affect suitability estimates to a large degree, but variations in model structure had a large impact on our suitability estimates. Our Dempster-Shafer analysis supported the belief that a range of semi-arid areas were suitable for RVF epidemics and the plausibility that many other areas of the continent were suitable. Areas where high levels of uncertainty were highlighted

  16. The sero-epidemiology of Rift Valley fever in people in the Lake Victoria Basin of western Kenya.

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    Elizabeth Anne Jessie Cook

    2017-07-01

    Full Text Available Rift Valley fever virus (RVFV is a zoonotic arbovirus affecting livestock and people. This study was conducted in western Kenya where RVFV outbreaks have not previously been reported. The aims were to document the seroprevalence and risk factors for RVFV antibodies in a community-based sample from western Kenya and compare this with slaughterhouse workers in the same region who are considered a high-risk group for RVFV exposure. The study was conducted in western Kenya between July 2010 and November 2012. Individuals were recruited from randomly selected homesteads and a census of slaughterhouses. Structured questionnaire tools were used to collect information on demographic data, health, and risk factors for zoonotic disease exposure. Indirect ELISA on serum samples determined seropositivity to RVFV. Risk factor analysis for RVFV seropositivity was conducted using multi-level logistic regression. A total of 1861 individuals were sampled in 384 homesteads. The seroprevalence of RVFV in the community was 0.8% (95% CI 0.5-1.3. The variables significantly associated with RVFV seropositivity in the community were increasing age (OR 1.2; 95% CI 1.1-1.4, p<0.001, and slaughtering cattle at the homestead (OR 3.3; 95% CI 1.0-10.5, p = 0.047. A total of 553 slaughterhouse workers were sampled in 84 ruminant slaughterhouses. The seroprevalence of RVFV in slaughterhouse workers was 2.5% (95% CI 1.5-4.2. Being the slaughterman, the person who cuts the animal's throat (OR 3.5; 95% CI 1.0-12.1, p = 0.047, was significantly associated with RVFV seropositivity. This study investigated and compared the epidemiology of RVFV between community members and slaughterhouse workers in western Kenya. The data demonstrate that slaughtering animals is a risk factor for RVFV seropositivity and that slaughterhouse workers are a high-risk group for RVFV seropositivity in this environment. These risk factors have been previously reported in other studies providing further

  17. Individual and Interactive Effects of Socio-Ecological Factors on Dengue Fever at Fine Spatial Scale: A Geographical Detector-Based Analysis.

    Science.gov (United States)

    Cao, Zheng; Liu, Tao; Li, Xing; Wang, Jin; Lin, Hualiang; Chen, Lingling; Wu, Zhifeng; Ma, Wenjun

    2017-07-17

    Background : Large spatial heterogeneity was observed in the dengue fever outbreak in Guangzhou in 2014, however, the underlying reasons remain unknown. We examined whether socio-ecological factors affected the spatial distribution and their interactive effects. Methods : Moran's I was applied to first examine the spatial cluster of dengue fever in Guangzhou. Nine socio-ecological factors were chosen to represent the urbanization level, economy, accessibility, environment, and the weather of the 167 townships/streets in Guangzhou, and then the geographical detector was applied to analyze the individual and interactive effects of these factors on the dengue outbreak. Results : Four clusters of dengue fever were identified in Guangzhou in 2014, including one hot spot in the central area of Guangzhou and three cold spots in the suburban districts. For individual effects, the temperature ( q = 0.33) was the dominant factor of dengue fever, followed by precipitation ( q = 0.24), road density ( q = 0.24), and water body area ( q = 0.23). For the interactive effects, the combination of high precipitation, high temperature, and high road density might result in increased dengue fever incidence. Moreover, urban villages might be the dengue fever hot spots. Conclusions : Our study suggests that some socio-ecological factors might either separately or jointly influence the spatial distribution of dengue fever in Guangzhou.

  18. Rift Valley Fever (RVF)

    Science.gov (United States)

    ... west Africa in 1987, and was linked to construction of the Senegal River Project. The project caused ... Diseases (NCEZID) Division of High-Consequence Pathogens and Pathology (DHCPP) Viral Special Pathogens Branch (VSPB) Email Recommend ...

  19. Valley Fever (Coccidioidomycosis)

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    ... Patients Medications that Weaken Your Immune System Outbreaks Rhizopus Investigation CDC at Work Global Fungal Diseases Cryptococcal ... May 22, 2017 Content source: Centers for Disease Control and Prevention National Center for Emerging and Zoonotic ...

  20. Valley Fever (Coccidioidomycosis) Statistics

    Science.gov (United States)

    ... Patients Medications that Weaken Your Immune System Outbreaks Rhizopus Investigation CDC at Work Global Fungal Diseases Cryptococcal ... November 9, 2017 Content source: Centers for Disease Control and Prevention National Center for Emerging and Zoonotic ...

  1. Environmental Variability and Fluctuation of Coccidioidomycosis (Valley Fever) In California: Based on a New Framework Involving Fungal Life Cycle

    Science.gov (United States)

    Jia, S.; Okin, G. S.; Shafir, S. C.

    2013-12-01

    Coccidioidomycosis (valley fever), caused by inhalation of spores from pathogenic fungus includingCoccidiodes immitis (C. immitis) and Coccidioides posadasii (C. posadasii), is a disease endemic to arid regions in the southwest US, as well as parts of Central and South America. With a projected increase of drought in this region, an improved understanding of environmental factors behind the outbreaks of coccidioidomycosis will enable the prediction of coccidioidomycosis in a changing climate regime. Previous research shows the infections correlate with climate conditions including precipitation, temperature, and dust. However, most studies focus only on the environmental conditions of fungus growth, which is the first stage in the fungal life cycle. In contrast, we extend the analysis to the following two stages in the life cycle, arthrospore formation and dispersal, to form a better model to predict the disease outbreaks. Besides climate conditions, we use relative spectral mixture analysis (RSMA) based on MODIS MOD43 nadir BRDF adjusted reflectance (NBAR) data to derive the relative dynamics of green vegetation, non-photosynthetic vegetation and bare soil coverage as better indicators of soil moisture, which is important for arthospore formation and dispersal. After detecting the hotspots of disease outbreaks, we correlate seasonal incidence from 2000 to 2010 with the environmental variables zero to eight seasons before to obtain candidates for stepwise regression. Regression result shows a seasonal difference in the leading explanatory variables. Such difference indicates the different seasonal main influential process from fungal life cycle. C. immitis (fungus responsible for coccidioidomycosis outbreaks in California) growth explains outbreaks in winter and fall better than other two stages in the life cycle, while arthospore formation is more responsible for spring and summer outbreaks. As the driest season, summer has the largest area related with arthospore

  2. Ecology and Epidemiology of Crimean-Congo Hemorrhagic Fever Virus Transmission in the Republic of Senegal

    Science.gov (United States)

    1989-02-01

    Fever. Case Antibody Titre, Number Village [gi lgG I Satara 1ll: 400 80 000 2 Ndeyboussat - 12 800 3 Ndeyboussat - 12 800 4 Thioury2 - 3 200 5 Thioury...1 600 6 PK28 - 6 400 7 Satara III - - 8 PK47 - - 1. ELISA test 2. Patient died 3. Negative - 45 - Table 9. Prevalence of anti-CCHF antibodies

  3. Fifty years of the integrated control concept: the role of landscape ecology in IPM in San Joaquin valley cotton.

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    Goodell, Peter B

    2009-12-01

    In defining the integrated control concept, Stern, Smith, van den Bosch and Hagan described 'understanding the ecosystem' as a key underpinning of the concept. In following years, Stern and van den Bosch continued to refine and expand the role of the ecological landscape. They and their colleagues developed cultural practices that took advantage of this understanding to limit the need of pesticide intervention in cotton in the San Joaquin Valley during the 1960s and 1970s. Research and extension activities in the intervening years built upon those fundamental concepts using geospatial tools and analytical techniques to refine current understanding and develop ecological landscape level approaches to manage Lygus hesperus (Knight) in San Joaquin Valley cotton, Gossypium hirsutum (L.) and more recently G. barbadense (L.). The result has been a significant drop in insecticide use against L. hesperus, with less than one application per season during the 1990 s and early 2000s. (c) 2009 Society of Chemical Industry.

  4. Ecological change in the lower Omo Valley around 2.8 Ma

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    Bibi, Faysal; Souron, Antoine; Bocherens, Hervé; Uno, Kevin; Boisserie, Jean-Renaud

    2013-01-01

    Late Pliocene climate changes have long been implicated in environmental changes and mammalian evolution in Africa, but high-resolution examinations of the fossil and climatic records have been hampered by poor sampling. By using fossils from the well-dated Shungura Formation (lower Omo Valley, northern Turkana Basin, southern Ethiopia), we investigate palaeodietary changes in one bovid and in one suid lineage from 3 to 2 Ma using stable isotope analysis of tooth enamel. Results show unexpectedly large increases in C4 dietary intake around 2.8 Ma in both the bovid and suid, and possibly in a previously reported hippopotamid species. Enamel δ13C values after 2.8 Ma in the bovid (Tragelaphus nakuae) are higher than recorded for any living tragelaphin, and are not expected given its conservative dental morphology. A shift towards increased C4 feeding at 2.8 Ma in the suid (Kolpochoerus limnetes) appears similarly decoupled from a well-documented record of dental evolution indicating gradual and progressive dietary change. The fact that two, perhaps three, disparate Pliocene herbivore lineages exhibit similar, and contemporaneous changes in dietary behaviour suggests a common environmental driver. Local and regional pollen, palaeosol and faunal records indicate increased aridity but no corresponding large and rapid expansion of grasslands in the Turkana Basin at 2.8 Ma. Our results provide new evidence supporting ecological change in the eastern African record around 2.8 Ma, but raise questions about the resolution at which different ecological proxies may be comparable, the correlation of vegetation and faunal change, and the interpretation of low δ13C values in the African Pliocene. PMID:23234862

  5. Prediction, Assessment of the Rift Valley Fever Activity in East and Southern Africa 2006–2008 and Possible Vector Control Strategies

    Science.gov (United States)

    Anyamba, Assaf; Linthicum, Kenneth J.; Small, Jennifer; Britch, Seth C.; Pak, Edwin; de La Rocque, Stephane; Formenty, Pierre; Hightower, Allen W.; Breiman, Robert F.; Chretien, Jean-Paul; Tucker, Compton J.; Schnabel, David; Sang, Rosemary; Haagsma, Karl; Latham, Mark; Lewandowski, Henry B.; Magdi, Salih Osman; Mohamed, Mohamed Ally; Nguku, Patrick M.; Reynes, Jean-Marc; Swanepoel, Robert

    2010-01-01

    Historical outbreaks of Rift Valley fever (RVF) since the early 1950s have been associated with cyclical patterns of the El Niño/Southern Oscillation (ENSO) phenomenon, which results in elevated and widespread rainfall over the RVF endemic areas of Africa. Using satellite measurements of global and regional elevated sea surface temperatures, elevated rainfall, and satellite derived-normalized difference vegetation index data, we predicted with lead times of 2–4 months areas where outbreaks of RVF in humans and animals were expected and occurred in the Horn of Africa, Sudan, and Southern Africa at different time periods from September 2006 to March 2008. Predictions were confirmed by entomological field investigations of virus activity and by reported cases of RVF in human and livestock populations. This represents the first series of prospective predictions of RVF outbreaks and provides a baseline for improved early warning, control, response planning, and mitigation into the future. PMID:20682905

  6. Detection of Rift Valley Fever Virus Interepidemic Activity in Some Hotspot Areas of Kenya by Sentinel Animal Surveillance, 2009–2012

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    Jacqueline Kasiiti Lichoti

    2014-01-01

    Full Text Available Rift Valley fever virus causes an important zoonotic disease of humans and small ruminants in Eastern Africa and is spread primarily by a mosquito vector. In this region, it occurs as epizootics that typically occur at 5–15-year intervals associated with unusual rainfall events. It has hitherto been known that the virus is maintained between outbreaks in dormant eggs of the mosquito vector and this has formed the basis of understanding of the epidemiology and control strategies of the disease. We show here that seroconversion and sporadic acute disease do occur during the interepidemic periods (IEPs in the absence of reported cases in livestock or humans. The finding indicates that previously undetected low-level virus transmission during the IEPs does occur and that epizootics may also be due to periodic expansion of mosquito vectors in the presence of both circulating virus and naïve animals.

  7. Infection and transmission of Rift Valley fever viruses lacking the NSs and/or NSm genes in mosquitoes: potential role for NSm in mosquito infection.

    Science.gov (United States)

    Crabtree, Mary B; Kent Crockett, Rebekah J; Bird, Brian H; Nichol, Stuart T; Erickson, Bobbie Rae; Biggerstaff, Brad J; Horiuchi, Kalanthe; Miller, Barry R

    2012-01-01

    Rift Valley fever virus is an arthropod-borne human and animal pathogen responsible for large outbreaks of acute and febrile illness throughout Africa and the Arabian Peninsula. Reverse genetics technology has been used to develop deletion mutants of the virus that lack the NSs and/or NSm virulence genes and have been shown to be stable, immunogenic and protective against Rift Valley fever virus infection in animals. We assessed the potential for these deletion mutant viruses to infect and be transmitted by Aedes mosquitoes, which are the principal vectors for maintenance of the virus in nature and emergence of virus initiating disease outbreaks, and by Culex mosquitoes which are important amplification vectors. Aedes aegypti and Culex quinquefasciatus mosquitoes were fed bloodmeals containing the deletion mutant viruses. Two weeks post-exposure mosquitoes were assayed for infection, dissemination, and transmission. In Ae. aegypti, infection and transmission rates of the NSs deletion virus were similar to wild type virus while dissemination rates were significantly reduced. Infection and dissemination rates for the NSm deletion virus were lower compared to wild type. Virus lacking both NSs and NSm failed to infect Ae. aegypti. In Cx. quinquefasciatus, infection rates for viruses lacking NSm or both NSs and NSm were lower than for wild type virus. In both species, deletion of NSm or both NSs and NSm reduced the infection and transmission potential of the virus. Deletion of both NSs and NSm resulted in the highest level of attenuation of virus replication. Deletion of NSm alone was sufficient to nearly abolish infection in Aedes aegypti mosquitoes, indicating an important role for this protein. The double deleted viruses represent an ideal vaccine profile in terms of environmental containment due to lack of ability to efficiently infect and be transmitted by mosquitoes.

  8. Infection and transmission of Rift Valley fever viruses lacking the NSs and/or NSm genes in mosquitoes: potential role for NSm in mosquito infection.

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    Mary B Crabtree

    Full Text Available BACKGROUND: Rift Valley fever virus is an arthropod-borne human and animal pathogen responsible for large outbreaks of acute and febrile illness throughout Africa and the Arabian Peninsula. Reverse genetics technology has been used to develop deletion mutants of the virus that lack the NSs and/or NSm virulence genes and have been shown to be stable, immunogenic and protective against Rift Valley fever virus infection in animals. We assessed the potential for these deletion mutant viruses to infect and be transmitted by Aedes mosquitoes, which are the principal vectors for maintenance of the virus in nature and emergence of virus initiating disease outbreaks, and by Culex mosquitoes which are important amplification vectors. METHODOLOGY AND PRINCIPAL FINDINGS: Aedes aegypti and Culex quinquefasciatus mosquitoes were fed bloodmeals containing the deletion mutant viruses. Two weeks post-exposure mosquitoes were assayed for infection, dissemination, and transmission. In Ae. aegypti, infection and transmission rates of the NSs deletion virus were similar to wild type virus while dissemination rates were significantly reduced. Infection and dissemination rates for the NSm deletion virus were lower compared to wild type. Virus lacking both NSs and NSm failed to infect Ae. aegypti. In Cx. quinquefasciatus, infection rates for viruses lacking NSm or both NSs and NSm were lower than for wild type virus. CONCLUSIONS/SIGNIFICANCE: In both species, deletion of NSm or both NSs and NSm reduced the infection and transmission potential of the virus. Deletion of both NSs and NSm resulted in the highest level of attenuation of virus replication. Deletion of NSm alone was sufficient to nearly abolish infection in Aedes aegypti mosquitoes, indicating an important role for this protein. The double deleted viruses represent an ideal vaccine profile in terms of environmental containment due to lack of ability to efficiently infect and be transmitted by mosquitoes.

  9. A Rift Valley Fever Vaccine Trial. 1. Side Effects and Serologic Response Over a Six-Month Follow-Up

    Science.gov (United States)

    1982-01-01

    to streptomycin case) and 0.1 ml x 3 (two cases). in one, dust allergy in three, hay fever, Peak response was noted on day 42 with allergic rhinitis ...1, 2, 3:0.5 ml 30/81 31.0 21/81 25.9 was mild erythema of 1-2 cm. Temper- Lot 1: 0.5 ml 19/45 42.2 11/45 24.4 ature, breathing , and chest examination...who had a titer of Nineteen study subjects reported 20 at day zero but less than 10 on day 10. hypersensitivity or allergic type condi- Antibody

  10. Ecological classification of wetland plant associations in the Lahontan Valley, Nevada

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    US Fish and Wildlife Service, Department of the Interior — In response to concerns regarding the conservation and management of wetland biodiversity within the Lahontan Valley, The Nature Conservancy, in cooperation with the...

  11. Limnology of the Green Lakes Valley: Phytoplankton ecology and dissolved organic matter biogeochemistry at a long-term ecological research site

    Science.gov (United States)

    Miller, Matthew P.; McKnight, Diane M.

    2015-01-01

    Background: Surface waters are the lowest points in the landscape, and therefore serve as excellent integrators and indicators of changes taking place in the surrounding terrestrial and atmospheric environment.Aims: Here we synthesise the findings of limnological studies conducted during the past 15 years in streams and lakes in the Green Lakes Valley, which is part of the Niwot Ridge Long-term Ecological Research (LTER) Site.Methods: The importance of these studies is discussed in the context of aquatic ecosystems as indicators, integrators, and regulators of environmental change. Specifically, investigations into climatic, hydrologic, and nutrient controls on present-day phytoplankton, and historical diatom, community composition in the alpine lake, Green Lake 4, are reviewed. In addition, studies of spatial and temporal patterns in dissolved organic matter (DOM) biogeochemistry and reactive transport modelling that have taken place in the Green Lakes Valley are highlighted.Results and conclusions: The findings of these studies identify specific shifts in algal community composition and DOM biogeochemistry that are indicative of changing environmental conditions and provide a framework for detecting future environmental change in the Green Lakes Valley and in other alpine watersheds. Moreover, the studies summarised here demonstrate the importance of long-term monitoring programmes such as the LTER programme.

  12. Chemotactic and inflammatory responses in the liver and brain are associated with pathogenesis of Rift Valley fever virus infection in the mouse.

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    Kimberly K Gray

    Full Text Available Rift Valley fever virus (RVFV is a major human and animal pathogen associated with severe disease including hemorrhagic fever or encephalitis. RVFV is endemic to parts of Africa and the Arabian Peninsula, but there is significant concern regarding its introduction into non-endemic regions and the potentially devastating effect to livestock populations with concurrent infections of humans. To date, there is little detailed data directly comparing the host response to infection with wild-type or vaccine strains of RVFV and correlation with viral pathogenesis. Here we characterized clinical and systemic immune responses to infection with wild-type strain ZH501 or IND vaccine strain MP-12 in the C57BL/6 mouse. Animals infected with live-attenuated MP-12 survived productive viral infection with little evidence of clinical disease and minimal cytokine response in evaluated tissues. In contrast, ZH501 infection was lethal, caused depletion of lymphocytes and platelets and elicited a strong, systemic cytokine response which correlated with high virus titers and significant tissue pathology. Lymphopenia and platelet depletion were indicators of disease onset with indications of lymphocyte recovery correlating with increases in G-CSF production. RVFV is hepatotropic and in these studies significant clinical and histological data supported these findings; however, significant evidence of a pro-inflammatory response in the liver was not apparent. Rather, viral infection resulted in a chemokine response indicating infiltration of immunoreactive cells, such as neutrophils, which was supported by histological data. In brains of ZH501 infected mice, a significant chemokine and pro-inflammatory cytokine response was evident, but with little pathology indicating meningoencephalitis. These data suggest that RVFV pathogenesis in mice is associated with a loss of liver function due to liver necrosis and hepatitis yet the long-term course of disease for those that

  13. A geographical information system-based multicriteria evaluation to map areas at risk for Rift Valley fever vector-borne transmission in Italy.

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    Tran, A; Ippoliti, C; Balenghien, T; Conte, A; Gely, M; Calistri, P; Goffredo, M; Baldet, T; Chevalier, V

    2013-11-01

    Rift Valley fever (RVF) is a severe mosquito-borne disease that is caused by a Phlebovirus (Bunyaviridae) and affects domestic ruminants and humans. Recently, its distribution widened, threatening Europe. The probability of the introduction and large-scale spread of Rift Valley fever virus (RVFV) in Europe is low, but localized RVF outbreaks may occur in areas where populations of ruminants and potential vectors are present. In this study, we assumed the introduction of the virus into Italy and focused on the risk of vector-borne transmission of RVFV to three main European potential hosts (cattle, sheep and goats). Five main potential mosquito vectors belonging to the Culex and Aedes genera that are present in Italy were identified in a literature review. We first modelled the geographical distribution of these five species based on expert knowledge and using land cover as a proxy of mosquito presence. The mosquito distribution maps were compared with field mosquito collections from Italy to validate the model. Next, the risk of RVFV transmission was modelled using a multicriteria evaluation (MCE) approach, integrating expert knowledge and the results of a literature review on host sensitivity and vector competence, feeding behaviour and abundance. A sensitivity analysis was performed to assess the robustness of the results with respect to expert choices. The resulting maps include (i) five maps of the vector distribution, (ii) a map of suitable areas for vector-borne transmission of RVFV and (iii) a map of the risk of RVFV vector-borne transmission to sensitive hosts given a viral introduction. Good agreement was found between the modelled presence probability and the observed presence or absence of each vector species. The resulting RVF risk map highlighted strong spatial heterogeneity and could be used to target surveillance. In conclusion, the geographical information system (GIS)-based MCE served as a valuable framework and a flexible tool for mapping the

  14. Combining hydrology and mosquito population models to identify the drivers of Rift Valley fever emergence in semi-arid regions of West Africa.

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    Valérie Soti

    Full Text Available BACKGROUND: Rift Valley fever (RVF is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine their presence, biology, and abundance. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. The assumed importance of temporary ponds and rainfall temporal distribution therefore needs to be investigated. METHODOLOGY/PRINCIPAL FINDINGS: A hydrological model is combined with a mosquito population model to predict the abundance of the two main mosquito species (Aedes vexans and Culex poicilipes involved in RVFV transmission in Senegal. The study area is an agropastoral zone located in the Ferlo Valley, characterized by a dense network of temporary water ponds which constitute mosquito breeding sites. The hydrological model uses daily rainfall as input to simulate variations of pond surface areas. The mosquito population model is mechanistic, considers both aquatic and adult stages and is driven by pond dynamics. Once validated using hydrological and entomological field data, the model was used to simulate the abundance dynamics of the two mosquito species over a 43-year period (1961-2003. We analysed the predicted dynamics of mosquito populations with regards to the years of main outbreaks. The results showed that the main RVF outbreaks occurred during years with simultaneous high abundances of both species. CONCLUSION/SIGNIFICANCE: Our study provides for the first time a mechanistic insight on RVFV transmission in West Africa. It highlights the complementary roles of Aedes vexans and Culex poicilipes mosquitoes in virus transmission, and recommends

  15. A temperature-limited assessment of the risk of Rift Valley fever transmission and establishment in the continental United States of America

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    Sarah K. Konrad

    2012-05-01

    Full Text Available The rapid spread of West Nile virus across North America after its introduction in 1999 highlights the potential for foreign arboviruses to become established in the United States of America. Of particular concern is Rift Valley fever virus (RVFV, which has been responsible for multiple African epidemics resulting in death of both humans and livestock, as well as major economic disruption due to livestock loss and trade restrictions. Modern globalization, travel, and commerce allow viruses to easily jump from one continent to another; and it is likely only a matter of time before RVFV reaches North American shores. We used a degree-day model in combination with livestock population data and a pathways analysis to identify regions and times where RVFV is most likely to enter and become established in the United States of America. Transmission risk of the disease varies across the country from 325 annual risk days in parts of Florida to zero risk days in the far North and in high mountain regions. Areas of particular concern are where there are a high number of possible transmission days, a large livestock population, and proximity to likely locations for the disease to enter the country via mosquito vector or human host. These areas should be monitored closely during transmission “risk seasons” so that if the virus does enter the country and begins to become established, it can be quickly controlled and eliminated before spreading further. Areas most at risk include the Baltimore and New York City metro areas as well as much of the region between these urban centers; most of Texas, especially around Houston; Florida; Atlanta; southwest Nebraska; southern California and Arizona; and the central valley of California.

  16. Microbial ecology of extreme environments: Antarctic dry valley yeasts and growth in substrate limited habitats

    Science.gov (United States)

    Vishniac, H. S.

    1981-01-01

    The multiple stresses temperature, moisture, and for chemoheterotrophs, sources of carbon and energy of the Dry Valley Antarctica soils allow at best depauperate communities, low in species diversity and population density. The nature of community structure, the operation of biogeochemical cycles, the evolution and mechanisms of adaptation to this habitat are of interest in informing speculations upon life on other planets as well as in modeling the limits of gene life. Yeasts of the Cryptococcus vishniacil complex (Basidiobiastomycetes) are investigated, as the only known indigenes of the most hostile, lichen free, parts of the Dry Valleys. Methods were developed for isolating these yeasts (methods which do not exclude the recovery of other microbiota). The definition of the complex was refined and the importance of nitrogen sources was established as well as substrate competition in fitness to the Dry Valley habitats.

  17. Ecology of the Tick-Borne Phlebovirus Causing Severe Fever with Thrombocytopenia Syndrome in an Endemic Area of China.

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    Zhifeng Li

    2016-04-01

    Full Text Available Severe fever with thrombocytopenia syndrome (SFTS is caused by SFTS virus (SFTSV, a tick-borne phlebovirus in family Bunyaviridae. Studies have found that humans, domestic and wildlife animals can be infected by SFTSV. However, the viral ecology, circulation, and transmission remain largely unknown.Sixty seven human SFTS cases were reported and confirmed by virus isolation or immunofluorescence assay between 2011 and 2014. In 2013-2014 we collected 9,984 ticks from either vegetation or small wild mammals in the endemic area in Jiangsu, China, and detected SFTSV-RNA by real-time RT-PCR in both questing and feeding Haemaphysalis longicornis and H. flava. Viral RNA was identified in larvae of H. longicornis prior to a first blood meal, which has never been confirmed previously in nature. SFTSV-RNA and antibodies were also detected by RT-PCR and ELISA, respectively, in wild mammals including Erinaceus europaeus and Sorex araneus. A live SFTSV was isolated from Erinaceus europaeus captured during the off tick-feeding season and with a high SFTSV antibody titer. Furthermore, SFTSV antibodies were detected in the migratory birds Anser cygnoides and Streptopelia chinensis using ELISA.The detection of SFTSV-RNA in non-engorged larvae indicated that vertical transmission of SFTSV in H. longicornis might occur in nature, which suggests that H. longicornis is a putative reservoir host of SFTSV. Small wild mammals such as Erinaceus europaeus and Sorex araneus could be infected by SFTSV and may serve as natural amplifying hosts. Our data unveiled that wild birds could be infected with SFTSV or carry SFTSV-infected ticks and thus might contribute to the long-distance spread of SFTSV via migratory flyways. These findings provide novel insights for understanding SFTSV ecology, reservoir hosts, and transmission in nature and will help develop new measures in preventing its rapid spread both regionally and globally.

  18. Ecology of the Tick-Borne Phlebovirus Causing Severe Fever with Thrombocytopenia Syndrome in an Endemic Area of China

    Science.gov (United States)

    Hu, Jianli; Liu, Wendong; Wang, Xiaochen; Zhang, Lei; Ji, Zhengmin; Feng, Zhi; Li, Luxun; Shen, Aihua; Liu, Xuejian; Zhao, Hongjun; Tan, Wenwen; Zhou, Jiangang; Qi, Xian; Zhu, Yefei; Tang, Fenyang; Cardona, Carol J.; Xing, Zheng

    2016-01-01

    Background Severe fever with thrombocytopenia syndrome (SFTS) is caused by SFTS virus (SFTSV), a tick-borne phlebovirus in family Bunyaviridae. Studies have found that humans, domestic and wildlife animals can be infected by SFTSV. However, the viral ecology, circulation, and transmission remain largely unknown. Methodology/Principal Findings Sixty seven human SFTS cases were reported and confirmed by virus isolation or immunofluorescence assay between 2011 and 2014. In 2013–2014 we collected 9,984 ticks from either vegetation or small wild mammals in the endemic area in Jiangsu, China, and detected SFTSV-RNA by real-time RT-PCR in both questing and feeding Haemaphysalis longicornis and H. flava. Viral RNA was identified in larvae of H. longicornis prior to a first blood meal, which has never been confirmed previously in nature. SFTSV-RNA and antibodies were also detected by RT-PCR and ELISA, respectively, in wild mammals including Erinaceus europaeus and Sorex araneus. A live SFTSV was isolated from Erinaceus europaeus captured during the off tick-feeding season and with a high SFTSV antibody titer. Furthermore, SFTSV antibodies were detected in the migratory birds Anser cygnoides and Streptopelia chinensis using ELISA. Conclusions/Significance The detection of SFTSV-RNA in non-engorged larvae indicated that vertical transmission of SFTSV in H. longicornis might occur in nature, which suggests that H. longicornis is a putative reservoir host of SFTSV. Small wild mammals such as Erinaceus europaeus and Sorex araneus could be infected by SFTSV and may serve as natural amplifying hosts. Our data unveiled that wild birds could be infected with SFTSV or carry SFTSV-infected ticks and thus might contribute to the long-distance spread of SFTSV via migratory flyways. These findings provide novel insights for understanding SFTSV ecology, reservoir hosts, and transmission in nature and will help develop new measures in preventing its rapid spread both regionally and

  19. Climate impacts on environmental risks evaluated from space: a contribution to social benefits within the GEOSS Health Area: The case of Rift Valley Fever in Senegal

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    Tourre, Y. M.

    2009-12-01

    Climate and environment vary on many spatio-temporal scales, including climate change, with impacts on ecosystems, vector-borne diseases and public health worldwide. This study is to enable societal benefits from a conceptual approach by mapping climatic and environmental conditions from space and understanding the mechanisms within the Health Social Benefit GEOSS area. The case study is for Rift Valley Fever (RVF) epidemics in Senegal is presented. Ponds contributing to mosquitoes’ thriving, were identified from remote sensing using high-resolution SPOT-5 satellite images. Additional data on ponds’ dynamics and rainfall events (obtained from the Tropical Rainfall Measuring Mission) were combined with hydrological in-situ data. Localization of vulnerable hosts such as parked cattle (from QuickBird satellite) are also used. Dynamic spatio-temporal distribution of Aedes vexans density (one of the main RVF vectors) is based on the total rainfall amount and ponds’ dynamics. While Zones Potentially Occupied by Mosquitoes (ZPOM) are mapped, detailed risks areas, i.e. zones where hazards and vulnerability occur, are expressed in percentages of parks where cattle is potentially exposed to mosquitoes’ bites. This new conceptual approach, using remote-sensing techniques belonging to GEOSS, simply relies upon rainfall distribution also evaluated from space. It is meant to contribute to the implementation of integrated operational early warning system within the health application communities since climatic and environmental conditions (both natural and anthropogenic) are changing rapidly.

  20. Validation of an ELISA for the concurrent detection of total antibodies (IgM and IgG to Rift Valley fever virus

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    Charlotte E. Ellis

    2014-02-01

    Full Text Available Rift Valley fever virus (RVFV infects humans and livestock, causing haemorrhaging andabortions in animals. Three major RVF epizootics have occurred in South Africa since the1950s and the outbreak in 2010 had a mortality rate of 10.7% in humans. Accurate and earlydetection is therefore essential for management of this zoonotic disease. Enzyme-linkedimmunosorbent assays (ELISAs have been developed for the detection of either IgM or IgGantibodies to RVFV in animal sera. In this study, data are presented on the validation of adouble-antigen ELISA for the simultaneous detection of both classes of antibodies to RVFV ina single test. ELISA plates were coated with a recombinant nucleoprotein. The nucleoprotein,conjugated to horseradish peroxidase, was used as the detecting reagent. A total of 534 serafrom sheep and cattle were used in the validation. The sheep sera were collected during a RVFpathogenesis study at the Agricultural Research Council (ARC – Onderstepoort VeterinaryInstitute and the cattle sera were collected during an outbreak of RVF in 2008 at the ARC –Animal Production Institute in Irene, Pretoria. The ELISA had a diagnostic sensitivity of 98.4%and a specificity of 100% when compared to a commercial cELISA. This convenient and fastassay is suitable for use in serological surveys or monitoring immune responses in vaccinatedanimals.

  1. Common host-derived chemicals increase catches of disease-transmitting mosquitoes and can improve early warning systems for Rift Valley fever virus.

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    David P Tchouassi

    Full Text Available Rift Valley fever (RVF, a mosquito-borne zoonosis, is a major public health and veterinary problem in sub-Saharan Africa. Surveillance to monitor mosquito populations during the inter-epidemic period (IEP and viral activity in these vectors is critical to informing public health decisions for early warning and control of the disease. Using a combination of field bioassays, electrophysiological and chemical analyses we demonstrated that skin-derived aldehydes (heptanal, octanal, nonanal, decanal common to RVF virus (RVFV hosts including sheep, cow, donkey, goat and human serve as potent attractants for RVFV mosquito vectors. Furthermore, a blend formulated from the four aldehydes and combined with CO(2-baited CDC trap without a light bulb doubled to tripled trap captures compared to control traps baited with CO(2 alone. Our results reveal that (a because of the commonality of the host chemical signature required for attraction, the host-vector interaction appears to favor the mosquito vector allowing it to find and opportunistically feed on a wide range of mammalian hosts of the disease, and (b the sensitivity, specificity and superiority of this trapping system offers the potential for its wider use in surveillance programs for RVFV mosquito vectors especially during the IEP.

  2. Remote sensing and geographic information systems to predict the density of ruminants, hosts of Rift Valley fever virus in the Sahel.

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    Pin-Diop, Raphaëlle; Touré, Ibra; Lancelot, Renaud; Ndiaye, Magatte; Chavernac, David

    2007-01-01

    Rift Valley fever (RVF) is an acute arboviral disease of domestic ungulates and humans in Africa and the Middle East. Since the first epidemic in 1987, Senegal has been confronted with recurrent episodes of the disease. This study aimed to model spatial distribution of ruminants in the agropastoral area of Barkedji (Senegal) where the disease is enzootic. In this Sahelian ecosystem, livestock distribution mainly depends on the availability of resources. Accordingly, remote sensing and geographic information systems (GIS) were used to seek environmental indicators of livestock density. A high-resolution Landsat image was associated with landscape field data to describe the land-cover. A series of normalized difference vegetation index values gave an estimation of the phytomass. In addition the compounds of herders in the study zone were located and sampled. Three surveys were conducted during the rainy season to record the number of herds in each compound of the sample. All these data were overlaid in the GIS. A discriminant analysis was performed to associate the observed herd density with environmental data and to develop a predictive model for the entire study zone. The final result was a 1-km resolution raster map of herd density during a normal rainy season.

  3. Development and Assessment of a Geographic Knowledge-Based Model for Mapping Suitable Areas for Rift Valley Fever Transmission in Eastern Africa.

    Science.gov (United States)

    Tran, Annelise; Trevennec, Carlène; Lutwama, Julius; Sserugga, Joseph; Gély, Marie; Pittiglio, Claudia; Pinto, Julio; Chevalier, Véronique

    2016-09-01

    Rift Valley fever (RVF), a mosquito-borne disease affecting ruminants and humans, is one of the most important viral zoonoses in Africa. The objective of the present study was to develop a geographic knowledge-based method to map the areas suitable for RVF amplification and RVF spread in four East African countries, namely, Kenya, Tanzania, Uganda and Ethiopia, and to assess the predictive accuracy of the model using livestock outbreak data from Kenya and Tanzania. Risk factors and their relative importance regarding RVF amplification and spread were identified from a literature review. A numerical weight was calculated for each risk factor using an analytical hierarchy process. The corresponding geographic data were collected, standardized and combined based on a weighted linear combination to produce maps of the suitability for RVF transmission. The accuracy of the resulting maps was assessed using RVF outbreak locations in livestock reported in Kenya and Tanzania between 1998 and 2012 and the ROC curve analysis. Our results confirmed the capacity of the geographic information system-based multi-criteria evaluation method to synthesize available scientific knowledge and to accurately map (AUC = 0.786; 95% CI [0.730-0.842]) the spatial heterogeneity of RVF suitability in East Africa. This approach provides users with a straightforward and easy update of the maps according to data availability or the further development of scientific knowledge.

  4. Single-Dose Intranasal Treatment with DEF201 (Adenovirus Vectored Consensus Interferon Prevents Lethal Disease Due to Rift Valley Fever Virus Challenge

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    Brian B. Gowen

    2014-03-01

    Full Text Available Rift Valley fever virus (RVFV causes severe disease in humans and ungulates. The virus can be transmitted by mosquitoes, direct contact with infected tissues or fluids, or aerosol, making it a significant biological threat for which there is no approved vaccine or therapeutic. Herein we describe the evaluation of DEF201, an adenovirus-vectored interferon alpha which addresses the limitations of recombinant interferon alpha protein (cost, short half-life, as a pre- and post-exposure treatment in a lethal hamster RVFV challenge model. DEF201 was delivered intranasally to stimulate mucosal immunity and effectively bypass any pre-existing immunity to the vector. Complete protection against RVFV infection was observed from a single dose of DEF201 administered one or seven days prior to challenge while all control animals succumbed within three days of infection. Efficacy of treatment administered two weeks prior to challenge was limited. Post‑exposure, DEF201 was able to confer significant protection when dosed at 30 min or 6 h, but not at 24 h post-RVFV challenge. Protection was associated with reductions in serum and tissue viral loads. Our findings suggest that DEF201 may be a useful countermeasure against RVFV infection and further demonstrates its broad-spectrum capacity to stimulate single dose protective immunity.

  5. Population genetics of two key mosquito vectors of Rift Valley Fever virus reveals new insights into the changing disease outbreak patterns in Kenya.

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    David P Tchouassi

    2014-12-01

    Full Text Available Rift Valley fever (RVF outbreaks in Kenya have increased in frequency and range to include northeastern Kenya where viruses are increasingly being isolated from known (Aedes mcintoshi and newly-associated (Ae. ochraceus vectors. The factors contributing to these changing outbreak patterns are unclear and the population genetic structure of key vectors and/or specific virus-vector associations, in particular, are under-studied. By conducting mitochondrial and nuclear DNA analyses on >220 Kenyan specimens of Ae. mcintoshi and Ae. ochraceus, we uncovered high levels of vector complexity which may partly explain the disease outbreak pattern. Results indicate that Ae. mcintoshi consists of a species complex with one of the member species being unique to the newly-established RVF outbreak-prone northeastern region of Kenya, whereas Ae. ochraceus is a homogeneous population that appears to be undergoing expansion. Characterization of specimens from a RVF-prone site in Senegal, where Ae. ochraceus is a primary vector, revealed direct genetic links between the two Ae. ochraceus populations from both countries. Our data strongly suggest that unlike Ae. mcintoshi, Ae. ochraceus appears to be a relatively recent, single 'introduction' into Kenya. These results, together with increasing isolations from this vector, indicate that Ae. ochraceus will likely be of greater epidemiological importance in future RVF outbreaks in Kenya. Furthermore, the overall vector complexity calls into question the feasibility of mosquito population control approaches reliant on genetic modification.

  6. Co-housing of Rift Valley fever virus infected lambs with immunocompetent or immunosuppressed lambs does not result in virus transmission

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    Paul J Wichgers Schreur

    2016-03-01

    Full Text Available Rift Valley fever virus (RVFV is transmitted among susceptible animals by mosquito vectors. Although the virus can be isolated from nasal and oral swabs of infected animals and is known to be highly infectious when administered experimentally via oral or respiratory route, horizontal transmission of the virus is only sporadically reported in literature. We considered that immunosuppression resulting from stressful conditions in the field may increase the susceptibility to horizontally transmitted RVFV. Additionally, we reasoned that horizontal transmission may induce immune responses that could affect the susceptibility of contact-exposed animals to subsequent infection via mosquito vectors. To address these two hypotheses, viremic lambs were brought into contact with sentinel lambs. One group of sentinel lambs was treated with the immunosuppressive synthetic glucocorticosteroid dexamethasone and monitored for signs of disease and presence of virus in the blood and target organs. Another group of contact-exposed sentinel lambs remained untreated for three weeks and was subsequently challenged with RVFV. We found that none of the dexamethasone-treated contact-exposed lambs developed detectable viremia, antibody responses or significant increases in cytokine mRNA levels. Susceptibility of immunocompetent lambs to RVFV infection was not influenced by previous contact-exposure. Our results are discussed in light of previous findings.

  7. Ecological Niche Modeling Identifies Fine-Scale Areas at High Risk of Dengue Fever in the Pearl River Delta, China

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    Qiaoxuan Li

    2017-06-01

    Full Text Available Dengue fever (DF is one of the most common and rapidly spreading mosquito-borne viral diseases in tropical and subtropical regions. In recent years, this imported disease has posed a serious threat to public health in China, especially in the Pearl River Delta (PRD. Although the severity of DF outbreaks in the PRD is generally associated with known risk factors, fine scale assessments of areas at high risk for DF outbreaks are limited. We built five ecological niche models to identify such areas including a variety of climatic, environmental, and socioeconomic variables, as well as, in some models, extracted principal components. All the models we tested accurately identified the risk of DF, the area under the receiver operating characteristic curve (AUC were greater than 0.8, but the model using all original variables was the most accurate (AUC = 0.906. Socioeconomic variables had a greater impact on this model (total contribution 55.27% than climatic and environmental variables (total contribution 44.93%. We found the highest risk of DF outbreaks on the border of Guangzhou and Foshan (in the central PRD, and in northern Zhongshan (in the southern PRD. Our fine-scale results may help health agencies to focus epidemic monitoring tightly on the areas at highest risk of DF outbreaks.

  8. TEK and biodiversity management in agroforestry systems of different socio-ecological contexts of the Tehuacán Valley.

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    Vallejo-Ramos, Mariana; Moreno-Calles, Ana I; Casas, Alejandro

    2016-07-22

    Transformation of natural ecosystems into intensive agriculture is a main factor causing biodiversity loss worldwide. Agroforestry systems (AFS) may maintain biodiversity, ecosystem benefits and human wellbeing, they have therefore high potential for concealing production and conservation. However, promotion of intensive agriculture and disparagement of TEK endanger their permanence. A high diversity of AFS still exist in the world and their potentialities vary with the socio-ecological contexts. We analysed AFS in tropical, temperate, and arid environments, of the Tehuacan Valley, Mexico, to investigate how their capacity varies to conserve biodiversity and role of TEK influencing differences in those contexts. We hypothesized that biodiversity in AFS is related to that of forests types associated and the vigour of TEK and management. We conducted studies in a matrix of environments and human cultures in the Tehuacán Valley. In addition, we reviewed, systematized and compared information from other regions of Mexico and the world with comparable socio-ecological contexts in order to explore possible general patterns. Our study found from 26 % to nearly 90 % of wild plants species richness conserved in AFS, the decreasing proportion mainly associated to pressures for intensifying agricultural production and abandoning traditional techniques. Native species richness preserved in AFS is influenced by richness existing in the associated forests, but the main driver is how people preserve benefits of components and functions of ecosystems. Elements of modern agricultural production may coexist with traditional management patterns, but imposition of modern models may break possible balances. TEK influences decisions on what and how modern techniques may be advantageous for preserving biodiversity, ecosystem integrity in AFS and people's wellbeing. TEK, agroecology and other sciences may interact for maintaining and improving traditional AFS to increase biodiversity

  9. Deletion of the NSm virulence gene of Rift Valley fever virus inhibits virus replication in and dissemination from the midgut of Aedes aegypti mosquitoes.

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    Kading, Rebekah C; Crabtree, Mary B; Bird, Brian H; Nichol, Stuart T; Erickson, Bobbie Rae; Horiuchi, Kalanthe; Biggerstaff, Brad J; Miller, Barry R

    2014-02-01

    Previously, we investigated the role of the Rift Valley fever virus (RVFV) virulence genes NSs and NSm in mosquitoes and demonstrated that deletion of NSm significantly reduced the infection, dissemination, and transmission rates of RVFV in Aedes aegypti mosquitoes. The specific aim of this study was to further characterize midgut infection and escape barriers of RVFV in Ae. aegypti infected with reverse genetics-generated wild type RVFV (rRVF-wt) or RVFV lacking the NSm virulence gene (rRVF-ΔNSm) by examining sagittal sections of infected mosquitoes for viral antigen at various time points post-infection. Ae. aegypti mosquitoes were fed an infectious blood meal containing either rRVF-wt or rRVF-ΔNSm. On days 0, 1, 2, 3, 4, 6, 8, 10, 12, and 14 post-infection, mosquitoes from each experimental group were fixed in 4% paraformaldehyde, paraffin-embedded, sectioned, and examined for RVFV antigen by immunofluorescence assay. Remaining mosquitoes at day 14 were assayed for infection, dissemination, and transmission. Disseminated infections were observed in mosquitoes as early as three days post infection for both virus strains. However, infection rates for rRVF-ΔNSm were statistically significantly less than for rRVF-wt. Posterior midgut infections in mosquitoes infected with rRVF-wt were extensive, whereas midgut infections of mosquitoes infected with rRVF-ΔNSm were confined to one or a few small foci. Deletion of NSm resulted in the reduced ability of RVFV to enter, replicate, and disseminate from the midgut epithelial cells. NSm appears to have a functional role in the vector competence of mosquitoes for RVFV at the level of the midgut barrier.

  10. Deletion of the NSm virulence gene of Rift Valley fever virus inhibits virus replication in and dissemination from the midgut of Aedes aegypti mosquitoes.

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    Rebekah C Kading

    2014-02-01

    Full Text Available BACKGROUND: Previously, we investigated the role of the Rift Valley fever virus (RVFV virulence genes NSs and NSm in mosquitoes and demonstrated that deletion of NSm significantly reduced the infection, dissemination, and transmission rates of RVFV in Aedes aegypti mosquitoes. The specific aim of this study was to further characterize midgut infection and escape barriers of RVFV in Ae. aegypti infected with reverse genetics-generated wild type RVFV (rRVF-wt or RVFV lacking the NSm virulence gene (rRVF-ΔNSm by examining sagittal sections of infected mosquitoes for viral antigen at various time points post-infection. METHODOLOGY AND PRINCIPAL FINDINGS: Ae. aegypti mosquitoes were fed an infectious blood meal containing either rRVF-wt or rRVF-ΔNSm. On days 0, 1, 2, 3, 4, 6, 8, 10, 12, and 14 post-infection, mosquitoes from each experimental group were fixed in 4% paraformaldehyde, paraffin-embedded, sectioned, and examined for RVFV antigen by immunofluorescence assay. Remaining mosquitoes at day 14 were assayed for infection, dissemination, and transmission. Disseminated infections were observed in mosquitoes as early as three days post infection for both virus strains. However, infection rates for rRVF-ΔNSm were statistically significantly less than for rRVF-wt. Posterior midgut infections in mosquitoes infected with rRVF-wt were extensive, whereas midgut infections of mosquitoes infected with rRVF-ΔNSm were confined to one or a few small foci. CONCLUSIONS/SIGNIFICANCE: Deletion of NSm resulted in the reduced ability of RVFV to enter, replicate, and disseminate from the midgut epithelial cells. NSm appears to have a functional role in the vector competence of mosquitoes for RVFV at the level of the midgut barrier.

  11. Mapping of zones potentially occupied by Aedes vexans and Culex poicilipes mosquitoes, the main vectors of Rift Valley fever in Senegal

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    Yves M. Tourre

    2008-11-01

    Full Text Available A necessary condition for Rift Valley fever (RVF emergence is the presence of Aedes (Aedimorphus vexans and Culex (Culex poicilipes mosquitoes carrying the arbovirus and responsible for the infection. This paper presents a detailed mapping in the Sahelian region of Senegal of zones potentially occupied by these mosquitoes (ZPOMs whose population density is directly linked to ecozones in the vicinity of small ponds. The vectors habitats and breeding sites have been characterized through an integrated approach combining remote sensing technology, geographical information systems, geographical positioning systems and field observations for proper geo-referencing. From five SPOT-5 images (~10 m spatial resolution with appropriate channels, a meridional composite transect of 290 x 60 km was first constructed at the height of the summer monsoon. Subsequent ZPOMs covered major ecozones from north to south with different hydrological environments and different patterns pond distributions. It was found that an overall area of 12,817 ha ± 10% (about 0.8% of the transect is occupied by ponds with an average ZPOM 17 times larger than this (212,813 ha ± 10% or about 14% of the transect. By comparing the very humid year of 2003 with 2006 which had just below normal rainfall, the ZPOMs inter-annual variability was analyzed in a sandy-clayey ecozone with an important hydrofossil riverbed within the Ferlo region of Senegal. Very probably contributing to an increased abundance of vectors by the end of August 2003, it was shown that the aggregate pond area was already about 22 times larger than in August 2006, corresponding to an approximately five times larger total ZPOM. The results show the importance of pin-pointing small ponds (sizes down to 0.1 ha and their geographical distribution in order to assess animal exposure to the RVF vectors.

  12. Aerosol exposure to Rift Valley fever virus causes earlier and more severe neuropathology in the murine model, which has important implications for therapeutic development.

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    Christopher Reed

    Full Text Available Rift Valley fever virus (RVFV is an important mosquito-borne veterinary and human pathogen that can cause severe disease including acute-onset hepatitis, delayed-onset encephalitis, retinitis and blindness, or a hemorrhagic syndrome. Currently, no licensed vaccine or therapeutics exist to treat this potentially deadly disease. Detailed studies describing the pathogenesis of RVFV following aerosol exposure have not been completed and candidate therapeutics have not been evaluated following an aerosol exposure. These studies are important because while mosquito transmission is the primary means for human infection, it can also be transmitted by aerosol or through mucosal contact. Therefore, we directly compared the pathogenesis of RVFV following aerosol exposure to a subcutaneous (SC exposure in the murine model by analyzing survival, clinical observations, blood chemistry, hematology, immunohistochemistry, and virus titration of tissues. Additionally, we evaluated the effectiveness of the nucleoside analog ribavirin administered prophylactically to treat mice exposed by aerosol and SC. The route of exposure did not significantly affect the survival, chemistry or hematology results of the mice. Acute hepatitis occurred despite the route of exposure. However, the development of neuropathology occurred much earlier and was more severe in mice exposed by aerosol compared to SC exposed mice. Mice treated with ribavirin and exposed SC were partially protected, whereas treated mice exposed by aerosol were not protected. Early and aggressive viral invasion of brain tissues following aerosol exposure likely played an important role in ribavirin's failure to prevent mortality among these animals. Our results highlight the need for more candidate antivirals to treat RVFV infection, especially in the case of a potential aerosol exposure. Additionally, our study provides an account of the key pathogenetic differences in RVF disease following two potential

  13. A Stochastic Model to Study Rift Valley Fever Persistence with Different Seasonal Patterns of Vector Abundance: New Insights on the Endemicity in the Tropical Island of Mayotte.

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    Lisa Cavalerie

    Full Text Available Rift Valley fever (RVF is a zoonotic vector-borne disease causing abortion storms in cattle and human epidemics in Africa. Our aim was to evaluate RVF persistence in a seasonal and isolated population and to apply it to Mayotte Island (Indian Ocean, where the virus was still silently circulating four years after its last known introduction in 2007. We proposed a stochastic model to estimate RVF persistence over several years and under four seasonal patterns of vector abundance. Firstly, the model predicted a wide range of virus spread patterns, from obligate persistence in a constant or tropical environment (without needing vertical transmission or reintroduction to frequent extinctions in a drier climate. We then identified for each scenario of seasonality the parameters that most influenced prediction variations. Persistence was sensitive to vector lifespan and biting rate in a tropical climate, and to host viraemia duration and vector lifespan in a drier climate. The first epizootic peak was primarily sensitive to viraemia duration and thus likely to be controlled by vaccination, whereas subsequent peaks were sensitive to vector lifespan and biting rate in a tropical climate, and to host birth rate and viraemia duration in arid climates. Finally, we parameterized the model according to Mayotte known environment. Mosquito captures estimated the abundance of eight potential RVF vectors. Review of RVF competence studies on these species allowed adjusting transmission probabilities per bite. Ruminant serological data since 2004 and three new cross-sectional seroprevalence studies are presented. Transmission rates had to be divided by more than five to best fit observed data. Five years after introduction, RVF persisted in more than 10% of the simulations, even under this scenario of low transmission. Hence, active surveillance must be maintained to better understand the risk related to RVF persistence and to prevent new introductions.

  14. The nucleocapsid protein of Rift Valley fever virus is a potent human CD8+ T cell antigen and elicits memory responses.

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    Weidong Xu

    Full Text Available There is no licensed human vaccine currently available for Rift Valley Fever Virus (RVFV, a Category A high priority pathogen and a serious zoonotic threat. While neutralizing antibodies targeting the viral glycoproteins are protective, they appear late in the course of infection, and may not be induced in time to prevent a natural or bioterrorism-induced outbreak. Here we examined the immunogenicity of RVFV nucleocapsid (N protein as a CD8(+ T cell antigen with the potential for inducing rapid protection after vaccination. HLA-A*0201 (A2-restricted epitopic determinants were identified with N-specific CD8(+ T cells from eight healthy donors that were primed with dendritic cells transduced to express N, and subsequently expanded in vitro by weekly re-stimulations with monocytes pulsed with 59 15mer overlapping peptides (OLPs across N. Two immunodominant epitopes, VT9 (VLSEWLPVT, N(121-129 and IL9 (ILDAHSLYL, N165-173, were defined. VT9- and IL9-specific CD8(+ T cells identified by tetramer staining were cytotoxic and polyfunctional, characteristics deemed important for viral control in vivo. These peptides induced specific CD8(+ T cell responses in A2-transgenic mice, and more importantly, potent N-specific CD8(+ T cell reactivities, including VT9- and IL9-specific ones, were mounted by mice after a booster vaccination with the live attenuated RVF MP-12. Our data suggest that the RVFV N protein is a potent human T cell immunogen capable of eliciting broad, immunodominant CD8(+ T cell responses that are potentially protective. Understanding the immune responses to the nucleocapsid is central to the design of an effective RVFV vaccine irrespective of whether this viral protein is effective as a stand-alone immunogen or only in combination with other RVFV antigens.

  15. Safety and immunogenicity of Onderstepoort Biological Products’ Rift Valley fever Clone 13 vaccine in sheep and goats under field conditions in Senegal

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    Modou M. Lo

    2015-02-01

    Full Text Available This blinded field safety study was conducted in Senegal to assess safety and immunogenicity of administration of the registered dose of Rift Valley fever virus (RVFV Clone 13 vaccine (Onderstepoort Biological Products to sheep and goats of West African breeds under natural conditions. A total of 267 small ruminants (220 sheep, 47 goats were included; half received RVFV Clone 13 vaccine at the recommended dose and half received the diluent (as placebo only. The study was performed on three commercial farms in the northern and eastern region of Senegal in accordance with veterinary good clinical practices. The animals were observed daily for 3 days after vaccination, and then weekly for 1 year. In both sheep and goats vaccinated against RVFV seroconversion rates above 70% were recorded. No seroconversion related to RVFV was observed in placebo-treated animals. No statistically significant differences were determined between placebo and vaccinated groups for mean rectal temperatures for the first 3 days after administration (p > 0.05. No abnormal clinical signs related to treatment were noted, and only one slight injection site reaction was observed in one vaccinated animal for 2 days after vaccination. Out of 176 births assessed over 1 year (93 from the vaccinated group, 83 from the placebo group, 9 were abnormal in the placebo group and 3 in the vaccinated group (p > 0.05. The frequency of adverse events was similar in the placebo and vaccinated groups. RVFV Clone 13 vaccine administered according to the manufacturer’s instructions was safe and well tolerated in West African breeds of sheep and goats, including animals of approximately 6 months of age and pregnant females, under field conditions in Senegal. Antibody levels persisted up to 1 year after vaccination.

  16. Genetic Evidence for Rift Valley Fever Outbreaks in Madagascar Resulting from Virus Introductions from the East African Mainland rather than Enzootic Maintenance▿†‡

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    Carroll, Serena A.; Reynes, Jean-Marc; Khristova, Marina L.; Andriamandimby, Soa Fy; Rollin, Pierre E.; Nichol, Stuart T.

    2011-01-01

    Rift Valley fever virus (RVFV), a mosquito-borne phlebovirus, has been detected in Madagascar since 1979, with occasional outbreaks. In 2008 to 2009, a large RVFV outbreak was detected in Malagasy livestock and humans during two successive rainy seasons. To determine whether cases were due to enzootic maintenance of the virus within Madagascar or to importation from the East African mainland, nine RVFV whole genomic sequences were generated for viruses from the 1991 and 2008 Malagasy outbreaks. Bayesian coalescent analyses of available whole S, M, and L segment sequences were used to estimate the time to the most recent common ancestor for the RVFVs. The 1979 Madagascar isolate shared a common ancestor with strains on the mainland around 1972. The 1991 Madagascar isolates were in a clade distinct from that of the 1979 isolate and shared a common ancestor around 1987. Finally, the 2008 Madagascar viruses were embedded within a large clade of RVFVs from the 2006–2007 outbreak in East Africa and shared a common ancestor around 2003 to 2004. These results suggest that the most recent Madagascar outbreak was caused by a virus likely arriving in the country some time between 2003 and 2008 and that this outbreak may be an extension of the 2006–2007 East African outbreak. Clustering of the Malagasy sequences into subclades indicates that the viruses have continued to evolve during their short-term circulation within the country. These data are consistent with the notion that RVFV outbreaks in Madagascar result not from emergence from enzootic cycles within the country but from recurrent virus introductions from the East African mainland. PMID:21507967

  17. A spatially explicit metapopulation model and cattle trade analysis suggests key determinants for the recurrent circulation of rift valley Fever virus in a pilot area of madagascar highlands.

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    Nicolas, Gaëlle; Chevalier, Véronique; Tantely, Luciano Michaël; Fontenille, Didier; Durand, Benoît

    2014-12-01

    Rift Valley fever (RVF) is a vector-borne zoonotic disease that causes high morbidity and mortality in ruminants. In 2008-2009, a RVF outbreak affected the whole Madagascar island, including the Anjozorobe district located in Madagascar highlands. An entomological survey showed the absence of Aedes among the potential RVF virus (RVFV) vector species identified in this area, and an overall low abundance of mosquitoes due to unfavorable climatic conditions during winter. No serological nor virological sign of infection was observed in wild terrestrial mammals of the area, suggesting an absence of wild RVF virus (RVFV) reservoir. However, a three years serological and virological follow-up in cattle showed a recurrent RVFV circulation. The objective of this study was to understand the key determinants of this unexpected recurrent transmission. To achieve this goal, a spatial deterministic discrete-time metapopulation model combined with cattle trade network was designed and parameterized to reproduce the local conditions using observational data collected in the area. Three scenarios that could explain the RVFV recurrent circulation in the area were analyzed: (i) RVFV overwintering thanks to a direct transmission between cattle when viraemic cows calve, vectors being absent during the winter, (ii) a low level vector-based circulation during winter thanks to a residual vector population, without direct transmission between cattle, (iii) combination of both above mentioned mechanisms. Multi-model inference methods resulted in a model incorporating both a low level RVFV winter vector-borne transmission and a direct transmission between animals when viraemic cows calve. Predictions satisfactorily reproduced field observations, 84% of cattle infections being attributed to vector-borne transmission, and 16% to direct transmission. These results appeared robust according to the sensitivity analysis. Interweaving between agricultural works in rice fields, seasonality of

  18. A spatially explicit metapopulation model and cattle trade analysis suggests key determinants for the recurrent circulation of rift valley Fever virus in a pilot area of madagascar highlands.

    Directory of Open Access Journals (Sweden)

    Gaëlle Nicolas

    2014-12-01

    Full Text Available Rift Valley fever (RVF is a vector-borne zoonotic disease that causes high morbidity and mortality in ruminants. In 2008-2009, a RVF outbreak affected the whole Madagascar island, including the Anjozorobe district located in Madagascar highlands. An entomological survey showed the absence of Aedes among the potential RVF virus (RVFV vector species identified in this area, and an overall low abundance of mosquitoes due to unfavorable climatic conditions during winter. No serological nor virological sign of infection was observed in wild terrestrial mammals of the area, suggesting an absence of wild RVF virus (RVFV reservoir. However, a three years serological and virological follow-up in cattle showed a recurrent RVFV circulation. The objective of this study was to understand the key determinants of this unexpected recurrent transmission. To achieve this goal, a spatial deterministic discrete-time metapopulation model combined with cattle trade network was designed and parameterized to reproduce the local conditions using observational data collected in the area. Three scenarios that could explain the RVFV recurrent circulation in the area were analyzed: (i RVFV overwintering thanks to a direct transmission between cattle when viraemic cows calve, vectors being absent during the winter, (ii a low level vector-based circulation during winter thanks to a residual vector population, without direct transmission between cattle, (iii combination of both above mentioned mechanisms. Multi-model inference methods resulted in a model incorporating both a low level RVFV winter vector-borne transmission and a direct transmission between animals when viraemic cows calve. Predictions satisfactorily reproduced field observations, 84% of cattle infections being attributed to vector-borne transmission, and 16% to direct transmission. These results appeared robust according to the sensitivity analysis. Interweaving between agricultural works in rice fields

  19. Development and evaluation of one-step rRT-PCR and immunohistochemical methods for detection of Rift Valley fever virus in biosafety level 2 diagnostic laboratories.

    Science.gov (United States)

    Drolet, Barbara S; Weingartl, Hana M; Jiang, Jieyuan; Neufeld, James; Marszal, Peter; Lindsay, Robbin; Miller, Myrna M; Czub, Markus; Wilson, William C

    2012-02-01

    Rift Valley fever virus (RVFV) is a zoonotic insect transmitted virus endemic to Africa and the Arabian Peninsula. Infection causes abortions and high mortality in newborn ruminants. The overall human infection rate is rRT-PCR) assay was modified for quick virus inactivation for use in BSL-2 laboratories, evaluated on serum and tissue samples from experimentally infected lambs and calves, and compared to virus isolation. Viremia was detected in all inoculated sheep with titers reaching 10(6.5) plaque forming units/ml, or up to 10(10) viral RNA copies/ml. Viremia in calves was lower and not detected in all inoculated animals; however, all animals became transiently febrile and were infected as determined by rRT-PCR of tissues. Virus was isolated from rRT-PCR-positive liver and/or spleen in 33% of lamb and 41% of calf samples between 2 and 7 days post inoculation. For RVFV antigen detection, reagents are typically produced at BSL-3Ag or BSL-4 conditions and require inactivation and safety testing for use outside of containment. In this study, antiserum against recombinant RVFV-nucleocapsid (N) was produced to develop an immunohistochemical (IHC) assay which was subsequently evaluated on formalin fixed lamb and calf tissues at BSL-2 laboratory conditions. Antigen was detected by IHC in 79% of rRT-PCR-positive sheep and 70% of rRT-PCR-positive calf tissues tested. Once validated and approved by national regulatory agencies, these assays can be safely produced and distributed to regional diagnostic laboratories, providing capacity for early detection of RVFV in suspected ruminant samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. A LANDSCAPE ATLAS OF ECOLOGICAL VULNERABILITY: ARKANSAS' WHITE RIVER WATERSHED AND THE MISSISSIPPI ALLUVIAL VALLEY

    Science.gov (United States)

    In July, 2000 the U.S. EPA's Office of Research and Development was requested to collaborate in a U.S. EPA Region 6 'Regional Applied Research Effort' (RARE). The primary goal of this RARE is to utilize current science and technology to improve the ecological vulnerability asses...

  1. Diagnosis and Chemotherapy of Human Trypanosomiasis and Vector Ecology of Rift Valley Fever and Congo-Crimean Hemorrhagic Fever in Kenya

    Science.gov (United States)

    1991-11-06

    mouse models when DFMO was administered in combination with one of a number of drugs, for instance bleomycin, diminazene, nifurtimox , suramin...combination with melarsoprol, in combination with suramin, in combination with both nifurtimox and suramin. The trials were designed in the belief that DFMO...denotes a case which was never free of trypanosomes KETRI Mid-term Report DAMDi7-90-Z-0005 9 (4) DFMO AND NIFURTIMOX (LampitR - Bayer) COMBINED WITH

  2. Over-winter ecology of Oncorhynchus nerka in the Sawtooth Valley Lakes

    Energy Technology Data Exchange (ETDEWEB)

    Steinhart, G.B.; Wurtsbaugh, W.A.

    1996-05-01

    Included in this section of the report on limnology of Lakes in the Snake River Plain are descriptions of winter limnological conditions and kokanee growth characteristics from 1993 to 1995. The winter is usually a very harsh period for animals, and little is know about the over-winter ecology os sockeye salmon. They are active a temperatures below 4 F. The chapter discusses methods and results. 14 figs, 4 tabs.

  3. An investigation into an outbreak of Rift Valley fever on a cattle farm in Bela-Bela, South Africa, in 2008

    Directory of Open Access Journals (Sweden)

    Lourenço P. Mapaco

    2012-04-01

    Full Text Available In 2008, a suspected outbreak of Rift Valley fever (RVF was reported on a farm in the Bela-Bela area, Limpopo Province, South Africa. Seven calves died on the affected dairy farm, where no RVF vaccination programme was practised. No apparent clinical disease was reported in the other 300 cattle (33 calves included or 200 sheep on the farm. During the outbreak, blood samples from 77.7% (233/300 of the cattle and 36.5% (73/200 of the sheep were collected on the affected farm and 55 blood samples were taken from cattle on a neighbouring farm. Eight weeks later, 78% of the cattle (234/300 and 42.5% of the sheep (85/200 were bled on the affected farm only. All sera were tested by an Immunoglobulin M (IgM-capture Enzymelinked immunosorbent assay (ELISA and by an indirect Immunoglobulin G (IgG ELISA. Selected IgM-positive (n = 14, IgG-positive (n = 23 and samples negative for both IgM and IgG-specific antibodies against RVF virus (n = 19 were tested using the serum neutralisation test (SNT. Sera from IgM-positive (n = 14 and negative (n = 20 animals were also tested by a TaqMan polymerase chain reaction (PCR. On the affected farm, 7% (16/233 of the cattle were IgM-positive and 13.7% (32/233 IgG-positive at the first bleed and 2% were IgM-positive at the second bleed, whilst the number of cattle positive for IgG-specific antibodies increased by 21.3% compared with the first bleed. Only 1.4% of sheep were positive for both IgM and IgG antibodies at the first collection; at the second bleed, IgM-positive cases decreased to 1.2%, whilst IgG-positive cases increased to 2.4%. Whilst no IgM-positive cattle were found on the neighbouring farm, 5.5% of cattle were IgG-positive. The SNT confirmed most of the ELISA results, whilst PCR results were all negative. Although serology results indicated virus circulation on both farms, the negative PCR results demonstrated that the animals were not viraemic at the time they were sampled. The movement of infected

  4. High content image-based screening of a protease inhibitor library reveals compounds broadly active against Rift Valley fever virus and other highly pathogenic RNA viruses.

    Science.gov (United States)

    Mudhasani, Rajini; Kota, Krishna P; Retterer, Cary; Tran, Julie P; Whitehouse, Chris A; Bavari, Sina

    2014-08-01

    High content image-based screening was developed as an approach to test a protease inhibitor small molecule library for antiviral activity against Rift Valley fever virus (RVFV) and to determine their mechanism of action. RVFV is the causative agent of severe disease of humans and animals throughout Africa and the Arabian Peninsula. Of the 849 compounds screened, 34 compounds exhibited ≥ 50% inhibition against RVFV. All of the hit compounds could be classified into 4 distinct groups based on their unique chemical backbone. Some of the compounds also showed broad antiviral activity against several highly pathogenic RNA viruses including Ebola, Marburg, Venezuela equine encephalitis, and Lassa viruses. Four hit compounds (C795-0925, D011-2120, F694-1532 and G202-0362), which were most active against RVFV and showed broad-spectrum antiviral activity, were selected for further evaluation for their cytotoxicity, dose response profile, and mode of action using classical virological methods and high-content imaging analysis. Time-of-addition assays in RVFV infections suggested that D011-2120 and G202-0362 targeted virus egress, while C795-0925 and F694-1532 inhibited virus replication. We showed that D011-2120 exhibited its antiviral effects by blocking microtubule polymerization, thereby disrupting the Golgi complex and inhibiting viral trafficking to the plasma membrane during virus egress. While G202-0362 also affected virus egress, it appears to do so by a different mechanism, namely by blocking virus budding from the trans Golgi. F694-1532 inhibited viral replication, but also appeared to inhibit overall cellular gene expression. However, G202-0362 and C795-0925 did not alter any of the morphological features that we examined and thus may prove to be good candidates for antiviral drug development. Overall this work demonstrates that high-content image analysis can be used to screen chemical libraries for new antivirals and to determine their mechanism of action and

  5. Trapping of Rift Valley Fever (RVF vectors using Light Emitting Diode (LED CDC traps in two arboviral disease hot spots in Kenya

    Directory of Open Access Journals (Sweden)

    Tchouassi David P

    2012-05-01

    Full Text Available Abstract Background Mosquitoes’ response to artificial lights including color has been exploited in trap designs for improved sampling of mosquito vectors. Earlier studies suggest that mosquitoes are attracted to specific wavelengths of light and thus the need to refine techniques to increase mosquito captures following the development of super-bright light-emitting diodes (LEDs which emit narrow wavelengths of light or very specific colors. Therefore, we investigated if LEDs can be effective substitutes for incandescent lamps used in CDC light traps for mosquito surveillance, and if so, determine the best color for attraction of important Rift Valley Fever (RFV vectors. Methods The efficiency of selected colored LED CDC light traps (red, green, blue, violet, combination of blue-green-red (BGR to sample RVF vectors was evaluated relative to incandescent light (as control in a CDC light trap in two RVF hotspots (Marigat and Ijara districts in Kenya. In field experiments, traps were baited with dry ice and captures evaluated for Aedes tricholabis, Ae. mcintoshi, Ae. ochraceus, Mansonia uniformis, Mn. africana and Culex pipiens, following Latin square design with days as replicates. Daily mosquito counts per treatment were analyzed using a generalized linear model with Negative Binomial error structure and log link using R. The incidence rate ratios (IRR that mosquito species chose other treatments instead of the control, were estimated. Results Seasonal preference of Ae.mcintoshi and Ae. ochraceus at Ijara was evident with a bias towards BGR and blue traps respectively in one trapping period but this pattern waned during another period at same site with significantly low numbers recorded in all colored traps except blue relative to the control. Overall results showed that higher captures of all species were recorded in control traps compared to the other LED traps (IRR  Conclusion Based on our trapping design and color, none of the LEDs

  6. High content image-based screening of a protease inhibitor library reveals compounds broadly active against Rift Valley fever virus and other highly pathogenic RNA viruses.

    Directory of Open Access Journals (Sweden)

    Rajini Mudhasani

    2014-08-01

    Full Text Available High content image-based screening was developed as an approach to test a protease inhibitor small molecule library for antiviral activity against Rift Valley fever virus (RVFV and to determine their mechanism of action. RVFV is the causative agent of severe disease of humans and animals throughout Africa and the Arabian Peninsula. Of the 849 compounds screened, 34 compounds exhibited ≥ 50% inhibition against RVFV. All of the hit compounds could be classified into 4 distinct groups based on their unique chemical backbone. Some of the compounds also showed broad antiviral activity against several highly pathogenic RNA viruses including Ebola, Marburg, Venezuela equine encephalitis, and Lassa viruses. Four hit compounds (C795-0925, D011-2120, F694-1532 and G202-0362, which were most active against RVFV and showed broad-spectrum antiviral activity, were selected for further evaluation for their cytotoxicity, dose response profile, and mode of action using classical virological methods and high-content imaging analysis. Time-of-addition assays in RVFV infections suggested that D011-2120 and G202-0362 targeted virus egress, while C795-0925 and F694-1532 inhibited virus replication. We showed that D011-2120 exhibited its antiviral effects by blocking microtubule polymerization, thereby disrupting the Golgi complex and inhibiting viral trafficking to the plasma membrane during virus egress. While G202-0362 also affected virus egress, it appears to do so by a different mechanism, namely by blocking virus budding from the trans Golgi. F694-1532 inhibited viral replication, but also appeared to inhibit overall cellular gene expression. However, G202-0362 and C795-0925 did not alter any of the morphological features that we examined and thus may prove to be good candidates for antiviral drug development. Overall this work demonstrates that high-content image analysis can be used to screen chemical libraries for new antivirals and to determine their

  7. Trapping of Rift Valley Fever (RVF) vectors using light emitting diode (LED) CDC traps in two arboviral disease hot spots in Kenya.

    Science.gov (United States)

    Tchouassi, David P; Sang, Rosemary; Sole, Catherine L; Bastos, Armanda D S; Cohnstaedt, Lee W; Torto, Baldwyn

    2012-05-19

    Mosquitoes' response to artificial lights including color has been exploited in trap designs for improved sampling of mosquito vectors. Earlier studies suggest that mosquitoes are attracted to specific wavelengths of light and thus the need to refine techniques to increase mosquito captures following the development of super-bright light-emitting diodes (LEDs) which emit narrow wavelengths of light or very specific colors. Therefore, we investigated if LEDs can be effective substitutes for incandescent lamps used in CDC light traps for mosquito surveillance, and if so, determine the best color for attraction of important Rift Valley Fever (RFV) vectors. The efficiency of selected colored LED CDC light traps (red, green, blue, violet, combination of blue-green-red (BGR)) to sample RVF vectors was evaluated relative to incandescent light (as control) in a CDC light trap in two RVF hotspots (Marigat and Ijara districts) in Kenya. In field experiments, traps were baited with dry ice and captures evaluated for Aedes tricholabis, Ae. mcintoshi, Ae. ochraceus, Mansonia uniformis, Mn. africana and Culex pipiens, following Latin square design with days as replicates. Daily mosquito counts per treatment were analyzed using a generalized linear model with Negative Binomial error structure and log link using R. The incidence rate ratios (IRR) that mosquito species chose other treatments instead of the control, were estimated. Seasonal preference of Ae.mcintoshi and Ae. ochraceus at Ijara was evident with a bias towards BGR and blue traps respectively in one trapping period but this pattern waned during another period at same site with significantly low numbers recorded in all colored traps except blue relative to the control. Overall results showed that higher captures of all species were recorded in control traps compared to the other LED traps (IRR LEDs outcompeted the standard incandescent light. The data however provides preliminary evidence that a preference might exist

  8. Spatio-temporal variation in prevalence of Rift Valley fever: a post-epidemic serum survey in cattle and wildlife in Kenya

    Directory of Open Access Journals (Sweden)

    Olivia Wesula Lwande

    2015-12-01

    Full Text Available Background: Rift Valley fever (RVF is a fatal arthropod-borne zoonotic disease of livestock and humans. Since the identification of RVF in Kenya in the 1930s, repeated epizootics and epidemics coinciding with El Niño events have occurred in several locations in Africa and Saudi Arabia, causing mass deaths of livestock and humans. RVF is of great interest worldwide because of its negative effect on international livestock trade and its potential to spread globally. The latter is due to the increasing incidence of extreme climatic phenomena caused by global warming, as well as to the increase in global trade and international travel. How RVF is maintained and sustained between epidemics and epizootics is not clearly understood, but it has been speculated that wildlife reservoirs and trans-ovarian transmission in the vector may be important. Several studies have examined the role of wildlife and livestock in isolation or in a limited geographical location within the one country over a short time (usually less than a year. In this study, we examined the seroprevalence of anti-RVF antibodies in cattle and several wildlife species from several locations in Kenya over an inter-epidemic period spanning up to 7 years. Methods: A serological survey of immunoglobulin G (IgG antibodies to RVF using competitive ELISA was undertaken on 297 serum samples from different wildlife species at various locations in Kenya. The samples were collected between 2008 and 2015. Serum was also collected in 2014 from 177 cattle from Ol Pejeta Conservancy; 113 of the cattle were in close contact with wildlife and the other 64 were kept separate from buffalo and large game by an electric fence. Results: The seroprevalence of RVF virus (RVFV antibody was 11.6% in wildlife species during the study period. Cattle that could come in contact with wildlife and large game were all negative for RVFV. The seroprevalence was relatively high in elephants, rhinoceros, and buffalo, but

  9. The ecology of western equine encephalomyelitis virus in the Central Valley of California, 1945-1985.

    Science.gov (United States)

    Hardy, J L

    1987-11-01

    Reeves' concept of the summer transmission cycle of western equine encephalomyelitis virus in 1945 was that the virus was amplified in a silent transmission cycle involving mosquitoes, domestic chickens, and possibly wild birds, from which it could be transmitted tangentially to and cause disease in human and equine populations. Extensive field and laboratory studies done since 1945 in the Central Valley of California have more clearly defined the specific invertebrate and vertebrate hosts involved in the basic virus transmission cycle, but the overall concept remains unchanged. The basic transmission cycle involves Culex tarsalis as the primary vector mosquito species and house finches and house sparrows as the primary amplifying hosts. Secondary amplifying hosts, upon which Cx. tarsalis frequently feeds, include other passerine species, chickens, and possibly pheasants in areas where they are abundant. Another transmission cycle that most likely is initiated from the Cx. tarsalis-wild bird cycle involves Aedes melanimon and the blacktail jackrabbit. Like humans and horses, California ground squirrels, western tree squirrels, and a few other wild mammal species become infected tangentially with the virus but do not contribute significantly to virus amplification.

  10. Symptoms of Valley Fever (Coccidioidomycosis)

    Science.gov (United States)

    ... Patients Medications that Weaken Your Immune System Outbreaks Rhizopus Investigation CDC at Work Global Fungal Diseases Cryptococcal ... January 25, 2017 Content source: Centers for Disease Control and Prevention National Center for Emerging and Zoonotic ...

  11. Treatment for Valley Fever (Coccidioidomycosis)

    Science.gov (United States)

    ... Patients Medications that Weaken Your Immune System Outbreaks Rhizopus Investigation CDC at Work Global Fungal Diseases Cryptococcal ... January 26, 2017 Content source: Centers for Disease Control and Prevention National Center for Emerging and Zoonotic ...

  12. Sustainable smallholder poultry interventions to promote food security and social, agricultural, and ecological resilience in the Luangwa Valley, Zambia.

    Science.gov (United States)

    Dumas, Sarah E; Lungu, Luke; Mulambya, Nathan; Daka, Whiteson; McDonald, Erin; Steubing, Emily; Lewis, Tamika; Backel, Katherine; Jange, Jarra; Lucio-Martinez, Benjamin; Lewis, Dale; Travis, Alexander J

    2016-06-01

    In Zambia's Luangwa Valley, highly variable rainfall and lack of education, agricultural inputs, and market access constrain agricultural productivity, trapping smallholder farmers in chronic poverty and food insecurity. Human and animal disease (e.g. HIV and Newcastle Disease, respectively), further threaten the resilience of poor families. To cope with various shocks and stressors, many farmers employ short-term coping strategies that threaten ecosystem resilience. Community Markets for Conservation (COMACO) utilizes an agribusiness model to alleviate poverty and food insecurity through conservation farming, market development and value-added food production. COMACO promotes household, agricultural and ecological resilience along two strategic lines: improving recovery from shocks (mitigation) and reducing the risk of shock occurrence. Here we focus on two of COMACO's poultry interventions and present data showing that addressing health and management constraints within the existing village poultry system resulted in significantly improved productivity and profitability. However, once reliable productivity was achieved, farmers preferred to sell chickens rather than eat either the birds or their eggs. Sales of live birds were largely outside the community to avoid price suppression; in contrast, the sale of eggs from community-operated, semi-intensive egg production facilities was invariably within the communities. These facilities resulted in significant increases in both producer income and community consumption of eggs. This intervention therefore has the potential to improve not only producers' economic resilience, but also resilience tied to the food security and physical health of the entire community.

  13. Wild common bean in the Central Valley of Costa Rica: ecological distribution and molecular characterization

    Directory of Open Access Journals (Sweden)

    Rosa In\\u00E9s Gonz\\u00E1lez Torres

    2004-01-01

    Full Text Available Frijol silvestre en el Valle Central de Costa Rica: distribución ecológica y caracterización molecular. Este trabajo presenta una actualización sobre la distribución de las formas silvestres de fríjol común en Costa Rica, su ecología y su caracterización molecular. Ala fecha 22 poblaciones fueron encontradas en cuatro cuencas alrededor del Valle Central, generalmente en vegetaciones ruderales (frecuentemente bordes de cafetales, con estatuto de conservación variable (desde protegido a amenazado. Su caracterización molecular indica su pertenencia al acervo genético mesoamericano. Varios marcadores indican una variabilidad aumentada en las formas silvestres y permiten inferir la presencia de un fenómeno de flujo genético e introgresión desde materiales cultivados.

  14. Hemorrhagic Fevers

    Science.gov (United States)

    ... of viruses. These include the Ebola and Marburg, Lassa fever, and yellow fever viruses. VHFs have common ... the animals that carry them live. For example, Lassa fever is limited to rural areas of West ...

  15. Scarlet fever

    Science.gov (United States)

    ... streptococcus . This is the same bacteria that cause strep throat . Causes Scarlet fever was once a very serious ... fever is infection with the bacteria that cause strep throat. An outbreak of strep throat or scarlet fever ...

  16. Multi-faceted proteomic characterization of host protein complement of Rift Valley fever virus virions and identification of specific heat shock proteins, including HSP90, as important viral host factors.

    Directory of Open Access Journals (Sweden)

    Jonathan E Nuss

    Full Text Available Rift Valley fever is a potentially fatal disease of humans and domestic animals caused by Rift Valley fever virus (RVFV. Infection with RVFV in ruminants can cause near 100% abortion rates and recent outbreaks in naïve human populations have suggested case fatality rates of greater than thirty percent. To elucidate the roles that host proteins play during RVFV infection, proteomic analysis of RVFV virions was conducted using complementary analytical approaches, followed by functional validation studies of select identified host factors. Coupling the more traditional Gel LC/MS/MS approach (SDS PAGE followed by liquid chromatography tandem mass spectrometry with an alternative technique that preserves protein complexes allowed the protein complement of these viral particles to be thoroughly examined. In addition to viral proteins present within the virions and virion-associated host proteins, multiple macromolecular complexes were identified. Bioinformatic analysis showed that host chaperones were among over-represented protein families associated with virions, and functional experiments using siRNA gene silencing and small molecule inhibitors identified several of these heat shock proteins, including heat shock protein 90 (HSP90, as important viral host factors. Further analysis indicated that HSP inhibition effects occur during the replication/transcription phase of the virus life cycle, leading to significant lowering of viral titers without compromising the functional capacity of released virions. Overall, these studies provide much needed further insight into interactions between RVFV and host cells, increasing our understanding of the infection process and suggesting novel strategies for anti-viral development. In particular, considering that several HSP90 inhibitors have been advancing through clinical trials for cancer treatment, these results also highlight the exciting potential of repurposing HSP90 inhibitors to treat RVF.

  17. Climate-disease connections: Rift Valley Fever in Kenya Relações entre clima e doença: febre do Vale do Rift, no Quênia

    Directory of Open Access Journals (Sweden)

    Assaf Anyamba

    2001-01-01

    Full Text Available All known Rift Valley fever(RVF outbreaks in Kenya from 1950 to 1998 followed periods of abnormally high rainfall. On an interannual scale, periods of above normal rainfall in East Africa are associated with the warm phase of the El Niño/Southern Oscillation (ENSO phenomenon. Anomalous rainfall floods mosquito-breeding habitats called dambos, which contain transovarially infected mosquito eggs. The eggs hatch Aedes mosquitoes that transmit the RVF virus preferentially to livestock and to humans as well. Analysis of historical data on RVF outbreaks and indicators of ENSO (including Pacific and Indian Ocean sea surface temperatures and the Southern Oscillation Index indicates that more than three quarters of the RVF outbreaks have occurred during warm ENSO event periods. Mapping of ecological conditions using satellite normalized difference vegetation index (NDVI data show that areas where outbreaks have occurred during the satellite recording period (1981-1998 show anomalous positive departures in vegetation greenness, an indicator of above-normal precipitation. This is particularly observed in arid areas of East Africa, which are predominantly impacted by this disease. These results indicate a close association between interannual climate variability and RVF outbreaks in Kenya.Entre 1950 e 1998 houve surtos de febre no Vale do Rift, no Quênia, após períodos de aumentos pluviométricos anormais. Em escala interanual, esses períodos estiveram associados à fase quente do fenômeno ENSO (El Niño/Southern Oscillation na África Oriental. As chuvas alagam os criadouros de mosquitos - dambos -, cujos ovos, infectados pela via transovariana, eclodem, produzindo mosquitos Aedes, transmissores do vírus da febre do Vale do Rift aos seres humanos e, em especial, ao gado. A análise dos dados históricos sobre surtos de febre do Vale do Rift e indicadores do fenômeno ENSO - incluindo temperaturas superficiais dos Oceanos Pacífico e Índico e o

  18. Ecological niche modeling and distribution of Ornithodoros hermsi associated with tick-borne relapsing fever in western North America.

    Science.gov (United States)

    Sage, Kylie M; Johnson, Tammi L; Teglas, Michael B; Nieto, Nathan C; Schwan, Tom G

    2017-10-01

    Tick-borne relapsing fever in western North America is a zoonosis caused by the spirochete bacterium, Borrelia hermsii, which is transmitted by the bite of infected Ornithodoros hermsi ticks. The pathogen is maintained in natural cycles involving small rodent hosts such as chipmunks and tree squirrels, as well as the tick vector. In order for these ticks to establish sustained and viable populations, a narrow set of environmental parameters must exist, primarily moderate temperatures and moderate to high amounts of precipitation. Maximum Entropy Species Distribution Modeling (Maxent) was used to predict the species distribution of O. hermsi and B. hermsii through time and space based on current climatic trends and future projected climate changes. From this modeling process, we found that the projected current distributions of both the tick and spirochete align with known endemic foci for the disease. Further, global climate models predict a shift in the distribution of suitable habitat for the tick vector to higher elevations. Our predictions are useful for targeting surveillance efforts in areas of high risk in western North America, increasing the efficiency and accuracy of public health investigations and vector control efforts.

  19. Ecological niche modeling and distribution of Ornithodoros hermsi associated with tick-borne relapsing fever in western North America.

    Directory of Open Access Journals (Sweden)

    Kylie M Sage

    2017-10-01

    Full Text Available Tick-borne relapsing fever in western North America is a zoonosis caused by the spirochete bacterium, Borrelia hermsii, which is transmitted by the bite of infected Ornithodoros hermsi ticks. The pathogen is maintained in natural cycles involving small rodent hosts such as chipmunks and tree squirrels, as well as the tick vector. In order for these ticks to establish sustained and viable populations, a narrow set of environmental parameters must exist, primarily moderate temperatures and moderate to high amounts of precipitation. Maximum Entropy Species Distribution Modeling (Maxent was used to predict the species distribution of O. hermsi and B. hermsii through time and space based on current climatic trends and future projected climate changes. From this modeling process, we found that the projected current distributions of both the tick and spirochete align with known endemic foci for the disease. Further, global climate models predict a shift in the distribution of suitable habitat for the tick vector to higher elevations. Our predictions are useful for targeting surveillance efforts in areas of high risk in western North America, increasing the efficiency and accuracy of public health investigations and vector control efforts.

  20. Dengue fever

    Science.gov (United States)

    ... Endy TP, Rothman AL, Barrett AD. Flaviviruses (dengue, yellow fever, Japanese encephalitis, West Nile encephalitis, St. Louis encephalitis, tick-borne encephalitis, Kyasanur forest disease, Alkhurma hemorrhagic fever, Zika). In: Bennett JE, Dolin ...

  1. Lassa Fever

    Science.gov (United States)

    ... Search Form Controls Cancel Submit Search the CDC Lassa Fever Note: Javascript is disabled or is not ... US) French Recommend on Facebook Tweet Share Compartir Lassa fever is an acute viral illness that occurs ...

  2. Ecology

    Science.gov (United States)

    Ternjej, Ivancica; Mihaljevic, Zlatko

    2017-10-01

    Ecology is a science that studies the mutual interactions between organisms and their environment. The fundamental subject of interest in ecology is the individual. Topics of interest to ecologists include the diversity, distribution and number of particular organisms, as well as cooperation and competition between organisms, both within and among ecosystems. Today, ecology is a multidisciplinary science. This is particularly true when the subject of interest is the ecosystem or biosphere, which requires the knowledge and input of biologists, chemists, physicists, geologists, geographists, climatologists, hydrologists and many other experts. Ecology is applied in a science of restoration, repairing disturbed sites through human intervention, in natural resource management, and in environmental impact assessments.

  3. Critical controlling of PRED system of oasis ecology in the arid region of central Asia: a case study of Keriya River Valley oases, Xinjiang

    Science.gov (United States)

    Chen, Rui; Liu, Jiaqi; Niu, Wenyuan; Deng, Xiangzheng; Mu, Guijin; Wagner, Mayke; Geldmacher, Karl

    2003-07-01

    Oases is a special ecosystem formed in arid climate and hungriness environment, in which resident, water and soil are the principal factor and exchanges of materials, energy and information are the main functional characteristics. The oases regions in central Asia are not only the basilic cradle of civilization of human beings, but also the important strategic places in world growing awareness of the potential benefits. We choose Keriya River Basin oases in south of Xinjiang as a case to study critical controlling of Oases Evolution, Based on the theories and methods used for environmental geology, physical geography, land resource research, and oases ecology. This study try to indicate the essential factors driving the oases ecosystem and the interactional dynamic mechanism in different scales and levels, confirm the optimal equilibrium aggregate of harmonious development between Population, Resources, Environment and Development, and establish the critical controlling pattern of sustainable development. We advance the indicator system to research the evolution of the PRED System of oases in Keriya River valley oases, in basis of the information derived from the field investigation and local materials. According to inquisitional result based on technical support of Geographic Information System (GIS) and Remote Sense (RS), the comparisons and analyses are carried out in land use at the upper reaches, vegetation change in the middle reaches, and desertification at the lower reaches, which narrates the regulations of Keriya River Valley oases land cover dynamic change. The main land cover types represent distinct characteristics of the local place. On the basis of field survey and statistical data, we use ARCINFO software to preprocess these data and the 2 TM satellite images. Through analyzing these images resulting from post-classification compare, we sums up the concrete quantificational dynamic distributed data of 13 land types covering a span of 15 years and

  4. A review of ecological factors associated with the epidemiology of wildlife trypanosomiasis in the luangwa and zambezi valley ecosystems of zambia.

    Science.gov (United States)

    Munang'andu, Hetron Mweemba; Siamudaala, Victor; Munyeme, Musso; Nalubamba, King Shimumbo

    2012-01-01

    Trypanosomiasis has been endemic in wildlife in Zambia for more than a century. The disease has been associated with neurological disorders in humans. Current conservation strategies by the Zambian government of turning all game reserves into state-protected National Parks (NPs) and game management areas (GMAs) have led to the expansion of the wildlife and tsetse population in the Luangwa and Zambezi valley ecosystem. This ecological niche lies in the common tsetse fly belt that harbors the highest tsetse population density in Southern Africa. Ecological factors such as climate, vegetation and rainfall found in this niche allow for a favorable interplay between wild reservoir hosts and vector tsetse flies. These ecological factors that influence the survival of a wide range of wildlife species provide adequate habitat for tsetse flies thereby supporting the coexistence of disease reservoir hosts and vector tsetse flies leading to prolonged persistence of trypanosomiasis in the area. On the other hand, increase in anthropogenic activities poses a significant threat of reducing the tsetse and wildlife habitat in the area. Herein, we demonstrate that while conservation of wildlife and biodiversity is an important preservation strategy of natural resources, it could serve as a long-term reservoir of wildlife trypanosomiasis.

  5. A Review of Ecological Factors Associated with the Epidemiology of Wildlife Trypanosomiasis in the Luangwa and Zambezi Valley Ecosystems of Zambia

    Directory of Open Access Journals (Sweden)

    Hetron Mweemba Munang'andu

    2012-01-01

    Full Text Available Trypanosomiasis has been endemic in wildlife in Zambia for more than a century. The disease has been associated with neurological disorders in humans. Current conservation strategies by the Zambian government of turning all game reserves into state-protected National Parks (NPs and game management areas (GMAs have led to the expansion of the wildlife and tsetse population in the Luangwa and Zambezi valley ecosystem. This ecological niche lies in the common tsetse fly belt that harbors the highest tsetse population density in Southern Africa. Ecological factors such as climate, vegetation and rainfall found in this niche allow for a favorable interplay between wild reservoir hosts and vector tsetse flies. These ecological factors that influence the survival of a wide range of wildlife species provide adequate habitat for tsetse flies thereby supporting the coexistence of disease reservoir hosts and vector tsetse flies leading to prolonged persistence of trypanosomiasis in the area. On the other hand, increase in anthropogenic activities poses a significant threat of reducing the tsetse and wildlife habitat in the area. Herein, we demonstrate that while conservation of wildlife and biodiversity is an important preservation strategy of natural resources, it could serve as a long-term reservoir of wildlife trypanosomiasis.

  6. Occurrence, distribution, and ecological risk assessment of DDTs and heavy metals in surface sediments from Lake Awassa--Ethiopian Rift Valley Lake.

    Science.gov (United States)

    Yohannes, Yared Beyene; Ikenaka, Yoshinori; Saengtienchai, Aksorn; Watanabe, Kensuke P; Nakayama, Shouta M M; Ishizuka, Mayumi

    2013-12-01

    Dichlorodiphenyltrichloroethanes (DDTs) and heavy metals are ubiquitous contaminants with high bioaccumulation and persistence in the environment, which can have adverse effects on humans and animals. Although applications of DDTs have been banned in many countries, developing countries like Ethiopia are still using these for agricultural and medicinal purposes. In addition, heavy metals are naturally present in the aquatic environment and distributed globally. In this study, the occurrence, distribution, and ecological risk of DDTs and heavy metals in surface sediments from one of the Ethiopian rift valley lakes were studied. Twenty-five surface sediment samples from Lake Awassa, Ethiopia were collected and analyzed for DDTs and heavy metals. Results showed that concentrations of total DDTs ranged from 3.64 to 40.2 ng/g dry weight. High levels of DDTs were observed in the vicinity of inflow river side and coastal areas with agricultural activities. The heavy metals content were followed the order Zn>Ni>Pb>Cu>Cr>Co>As>Cd>Hg. Correlation analysis and principal components analysis demonstrated that heavy metals were originated from both natural and anthropogenic inputs. The levels of DDE and DDD in surface sediments exceeded the sediment quality guideline values, indicating that adverse effects may occur to the lake. A method based on toxic-response factor for heavy metals revealed that the calculated potential ecological risk indices showed low ecological risk for the water body.

  7. Report on the remedial investigation of Bear Creek Valley at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 6: Appendix G -- Baseline ecological risk assessment report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    This Remedial Investigation (RI) Report characterizes the nature and extent of contamination, evaluates the fate and transport of contaminants, and assesses risk to human health and the environment resulting from waste disposal and other US Department of Energy (DOE) operations in Bear Creek Valley (BCV). BCV, which is located within the DOE Oak Ridge Reservation (ORR) encompasses multiple waste units containing hazardous and radioactive wastes arising from operations at the adjacent Oak Ridge Y-12 Plant. The primary waste units discussed in this RI Report are the S-3 Site, Oil Landfarm (OLF), Boneyard/Burnyard (BYBY), Sanitary Landfill 1 (SL 1), and Bear Creek Burial Grounds (BCBG). These waste units, plus the contaminated media resulting from environmental transport of the wastes from these units, are the subject of this RI. This BCV RI Report represents the first major step in the decision-making process for the BCV watershed. The RI results, in concert with the follow-on FS will form the basis for the Proposed Plan and Record of Decision for all BCV sites. This comprehensive decision document process will meet the objectives of the watershed approach for BCV. Appendix G contains ecological risks for fish, benthic invertebrates, soil invertebrates, plants, small mammals, deer, and predator/scavengers (hawks and fox). This risk assessment identified significant ecological risks from chemicals in water, sediment, soil, and shallow ground water. Metals and PCBs are the primary contaminants of concern.

  8. Dengue fever

    African Journals Online (AJOL)

    Introduction. Dengue fever is caused by dengue viruses. (DENV). Transmission of DENV has increased dramatically in the past two decades making DENV the most important human pathogens among arthropod-borne viruses (1). About 50-. 100 million dengue fever infections occur every year in tropical and subtropical.

  9. Yellow Fever

    Science.gov (United States)

    ... febrile illness to severe liver disease with bleeding. Yellow fever disease is diagnosed based on symptoms, physical findings, laboratory testing, and travel history, including the possibility of exposure to ... specific treatment for yellow fever; care is based on symptoms. Steps to ...

  10. Ecology.

    Science.gov (United States)

    National Audubon Society, New York, NY.

    This set of teaching aids consists of nine Audubon Nature Bulletins, providing teachers and students with informational reading on various ecological topics. The bulletins have these titles: Schoolyard Laboratories, Owls and Predators, The Forest Community, Life in Freshwater Marshes, Camouflage in the Animal World, Life in the Desert, The…

  11. Ecological response to hydrological variability and catchment development: Insights from a shallow oxbow lake in Lower Mississippi Valley, Arkansas.

    Science.gov (United States)

    Bhattacharya, Ruchi; Hausmann, Sonja; Hubeny, J Bradford; Gell, Peter; Black, Jessica L

    2016-11-01

    The ecological response of shallow oxbow lakes to variability in hydrology and catchment development in large river floodplain ecosystems (RFE) in Arkansas remains largely unknown. Investigating these responses will advance our understanding of ecological evolution of oxbow lakes in response to the major environmental drivers, which will establish baseline conditions required to develop effective management practices for RFE. In this pilot study, we examined the potential of using a dated surface sediment core from Adams Bayou, a floodplain lake located within the Cache-Lower White River Ramsar site in SE Arkansas. Stratigraphic records of diatoms and sediment geochemistry were used to ascertain variation in Adams Bayou's ecological condition. During 1968-2008, in response to hydrological and anthropogenic changes, Adams Bayou's diatom assemblages progressed from predominantly benthic (Gomphonema parvulum and Meridion circulare) to primarily planktonic assemblage (Aulacoseira granulata and Cyclotella meneghiniana), along with a decrease in magnetic susceptibility (k) and % silt. Statistical analyses reveled that during 1968-2000, higher hydrological connectivity and catchment alterations drove Adams Bayou's ecosystem. After 2000, lower hydrological connectivity and increase in cultivation were the major drivers. The potential impact of increasing air temperature was also noted. The shift in Adams Bayou from a connected, clear, mesotrophic state to a relatively isolated, turbid and nutrient enriched state is consistent with regime shift models and highlights its sensitivity to a combination of environmental stresses prevalent in the catchment. Although fluvial systems pose challenges in establishing clear chronologies, oxbow lake sediments can be a effective paleoecological archives. Our work provides clear evidence for the change in the ecological character of this wetland of international significance and flags the need for a wider assessment of water bodies

  12. Dengue hemorrhagic fever

    Science.gov (United States)

    Hemorrhagic dengue; Dengue shock syndrome; Philippine hemorrhagic fever; Thai hemorrhagic fever; Singapore hemorrhagic fever ... Four different dengue viruses are known to cause dengue hemorrhagic fever. Dengue hemorrhagic fever occurs when a person is bitten by ...

  13. Sensitivity and specificity of real-time reverse transcription polymerase chain reaction, histopathology, and immunohistochemical labeling for the detection of Rift Valley fever virus in naturally infected cattle and sheep.

    Science.gov (United States)

    Odendaal, Lieza; Fosgate, Geoffrey T; Romito, Marco; Coetzer, Jacobus A W; Clift, Sarah J

    2014-01-01

    Real-time reverse transcription polymerase chain reaction (real-time RT-PCR), histopathology, and immunohistochemical labeling (IHC) were performed on liver specimens from 380 naturally infected cattle and sheep necropsied during the 2010 Rift Valley fever (RVF) epidemic in South Africa. Sensitivity (Se) and specificity (Sp) of real-time RT-PCR, histopathology, and IHC were estimated in a latent-class model using a Bayesian framework. The Se and Sp of real-time RT-PCR were estimated as 97.4% (95% confidence interval [CI] = 95.2-98.8%) and 71.7% (95% CI = 65-77.9%) respectively. The Se and Sp of histopathology were estimated as 94.6% (95% CI = 91-97.2%) and 92.3% (95% CI = 87.6-95.8%), respectively. The Se and Sp of IHC were estimated as 97.6% (95% CI = 93.9-99.8%) and 99.4% (95% CI = 96.9-100%), respectively. Decreased Sp of real-time RT-PCR was ascribed to cross-contamination of samples. Stratified analysis of the data suggested variations in test accuracy with fetuses and severely autolyzed specimens. The Sp of histopathology in fetuses (83%) was 9.3% lower than the sample population (92.3%). The Se of IHC decreased from 97.6% to 81.5% in the presence of severe autolysis. The diagnostic Se and Sp of histopathology was higher than expected, confirming the value of routine postmortem examinations and histopathology of liver specimens. Aborted fetuses, however, should be screened using a variety of tests in areas endemic for RVF, and results from severely autolyzed specimens should be interpreted with caution. The most feasible testing option for countries lacking suitably equipped laboratories seems to be routine histology in combination with IHC.

  14. Regional estimates of ecological services derived from U.S. Department of Agriculture conservation programs in the Mississippi Alluvial Valley

    Science.gov (United States)

    Faulkner, Stephen P.; Baldwin, Michael J.; Barrow, Wylie C.; Waddle, Hardin; Keeland, Bobby D.; Walls, Susan C.; James, Dale; Moorman, Tom

    2010-01-01

    The Mississippi Alluvial Valley (MAV) is the Nation?s largest floodplain and this once predominantly forested ecosystem provided significant habitat for a diverse flora and fauna, sequestered carbon in trees and soil, and stored floodwater, sediments, and nutrients within the floodplain. This landscape has been substantially altered by the conversion of nearly 75% of the riparian forests, predominantly to agricultural cropland, with significant loss and degradation of important ecosystem services. Large-scale efforts have been employed to restore the forest and wetland resources and the U.S. Department of Agriculture (USDA) Wetlands Reserve Program (WRP) and Conservation Reserve Program (CRP) represent some of the most extensive restoration programs in the MAV. The objective of the WRP is to restore and protect the functions and values of wetlands in agricultural landscapes with an emphasis on habitat for migratory birds and wetland-dependent wildlife, protection and improvement of water quality, flood attenuation, ground water recharge, protection of native flora and fauna, and educational and scientific scholarship.

  15. Ecological risk assessment and spatial distribution of some heavy metals in surface sediments of New Valley, Western Desert, Egypt

    Directory of Open Access Journals (Sweden)

    Mahmoud I.I. Mohamaden

    2017-03-01

    Sediment enrichment factor (EF showed that the variation values were from moderate to minor enrichment. The Geo-accumulation index calculations (Igeo proved that the investigated areas could be classified as unpolluted with the exception of Mute 13 and HO2 which were moderately polluted by Cd, while Ras was strongly polluted by Cd. HO1 and Ras revealed that they were a moderate to considerable ecological risk, respectively. Mean ERM quotient (MERMQ reflected that the surface sediments of HO3 and Mute 5 have 21% probability of toxicity.

  16. Rheumatic fever

    Science.gov (United States)

    ... condition are: Loss of control of emotions, with bouts of unusual crying or laughing Quick, jerky movements ... minor criteria include: Fever High ESR Joint pain Abnormal EKG You'll likely be diagnosed with rheumatic ...

  17. Typhoid fever

    Science.gov (United States)

    ... It is most commonly caused due to a bacteria called Salmonella typhi ( S typhi ). ... Enteric fever ... electrolyte packets. Antibiotics are given to kill the bacteria. ... check current recommendations before choosing an antibiotic.

  18. Yellow fever

    Science.gov (United States)

    ... SJ, Endy TP, Rothman AL, Barrett AD. Flaviviruses (dengue, yellow fever, Japanese encephalitis, West Nile encephalitis, St. ... any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should ...

  19. Q fever

    Science.gov (United States)

    ... bacteria can infect: Sheep Goats Cattle Dogs Cats Birds Rodents Ticks Infected animals shed these bacteria in: Birth products Feces Milk Urine Humans usually get Q fever by breathing in contaminated droplets released into the air by ...

  20. Dengue Fever

    Science.gov (United States)

    ... change the water in birdbaths, dog bowls, and flower vases at least once a week. By taking ... Cholera West Nile Virus First Aid: Vomiting Are Insect Repellents With DEET Safe for Kids? Dengue Fever ...

  1. Population size, group composition and behavioural ecology of geladas (Theropithecus gelada) and human-gelada conflict in Wonchit Valley, Ethiopia.

    Science.gov (United States)

    Kifle, Zewdu; Belay, Gurja; Bekele, Afework

    2013-11-01

    Primates that live in protected areas are intensively studied; however, those that live outside protected areas are less studied by primatologists. Therefore, the present study was carried out outside protected areas on the endemic gelada (Theropithecus gelada) to estimate the population size and group composition and human-gelada conflict in Wonchit Valley, Ethiopia from August 2008-March 2009. Total count method was used to determine the population size and group composition of geladas. A band of geladas was selected to carry out behavioural research. Data were collected on activity, diet and ranging patterns for one band of geladas using scan samples at 15 min intervals. Data on human-gelada conflict was gathered using questionnaire interview method. The total number of geladas in the study area was 1525. The average size of one-male unit was 16.96. Adult male to adult female sex ratio was 1.00:6.61. The average size of the band was 58.03. Group size ranged from 3 to 220. Geladas spent 65.2% of their time feeding, 16.3% moving, 4.6% resting and 13.9% socializing. The total time spent feeding on grass blades was 83.8% and 11.8% for bulbs and roots. The home range size was 1.5 km2 during the dry season and 0.2 km2 during the wet season. Geladas in the study area caused crop damage and shared pasture and drinking water with livestock. They consume crops during harvesting stage more than the seedling and vegetative stages. The study has immense contribution for the conservation and management of this endemic primate in unprotected areas.

  2. The ecology and epidemiology of Ross River and Murray Valley encephalitis viruses in Western Australia: examples of One Health in Action.

    Science.gov (United States)

    Mackenzie, John S; Lindsay, Michael D A; Smith, David W; Imrie, Allison

    2017-06-01

    Arboviruses are maintained and transmitted through an alternating biological cycle in arthropods and vertebrates, with largely incidental disease in humans and animals. As such, they provide excellent examples of One Health, as their health impact is inextricably linked to their vertebrate hosts, their arthropod vectors and the environment. Prevention and control requires a comprehensive understanding of these interactions, and how they may be effectively and safely modified. This review concentrates on human disease due to Ross River and Murray Valley encephalitis viruses, the two major arboviral pathogens in Australia. It describes how their pattern of infection and disease is influenced by natural climatic and weather patterns, and by anthropogenic activities. The latter includes human-mediated environmental manipulations, such as water impoundment infrastructures, human movements and migration, and community and social changes, such as urban spread into mosquito larval habitats. Effective interventions need to be directed at the environmental precursors of risk. This can best be achieved using One Health approaches to improve collaboration and coordination between different disciplines and cross-sectoral jurisdictions in order to develop more holistic mitigation and control procedures, and to address poorly understood ecological issues through multidisciplinary research. © The Author 2017. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.

  3. ECOLOGICAL REMEDIATION OF THE ŠOŠTANJ THERMAL POWER PLANT WITH RESPECT TO SUSTAINABLE DEVELOPMENT OF THE ŠALEK VALLEY, SLOVENIA

    Directory of Open Access Journals (Sweden)

    Samar Al Sayegh Petkovšek

    2010-01-01

    Full Text Available The Šalek valley used to be exposed to huge amounts of pollutants due to its close vicinity to the largest Slovene thermal power plant of Šoštanj (ŠTPP. Due to large emissions of SO2 and heavy metals as well as dumping of fly ash negative effects on the environment appeared (e.g. forest decline in area exposed to deposition of emission by the ŠTPP, pollution of lake Velenje and the river Paka. Therefore, several ecological remediation measures on the ŠTPP were implemented in the 1990s, and several research projects on reasons and effects of forest decline and degradation of environment began as well. A continuous and marked improving of the condition of both forest and freshwater ecosystems (of lake Velenje and the river Paka after the installation of desulphurization devices on Units 4 and 5 of the ŠTPP and construction of a closed loop system for the ash transportation is emphasized in the present paper.

  4. Dengue fever (image)

    Science.gov (United States)

    Dengue fever, or West Nile fever, is a mild viral illness transmitted by mosquitoes which causes fever, ... second exposure to the virus can result in Dengue hemorrhagic fever, a life-threatening illness.

  5. Yellow Fever Vaccine

    Science.gov (United States)

    What is yellow fever?Yellow fever is a serious disease caused by the yellow fever virus. It is found in certain parts of Africa and South America. Yellow fever is spread through the bite of an infected ...

  6. The role of fluvial geomorphic analysis and historical ecology in support of flood control channel management in the Livermore Valley, California

    Science.gov (United States)

    Beagle, J. R.; Pearce, S.; Stanford, B.; McKee, L. J.; Grossinger, R. M.

    2011-12-01

    Julie Beagle, Sarah Pearce, Bronwen Stanford, Lester McKee, Robin Grossinger Flood control, city, and county managers are under increasing pressure to include improved habitat and water quality function, in addition to normal flood control function, to operating procedures for flood channels. Obtaining permits for routine maintenance, such as sediment removal, is now more challenging unless management agencies can demonstrate high level understanding of modern channel processes in the context of historical ecosystem functions. To address this issue, San Francisco Estuary Institute has been working with local agencies throughout the Bay Area to measure and understand sediment supply, the causes and rates of sedimentation in facilities, the impacts of maintenance activities to habitat and species of interest, and to identify mitigation opportunities within the context of historical watershed functions. Ongoing research in the Alameda Creek watershed provides an example of the intersection between historical ecology and modern geomorphic analysis as a developed approach for informing local resource management decisions. Zone 7 Water Agency, in the northern area of the Alameda Creek watershed, maintains 37 miles of channels that receive and convey urban drainage from Livermore, Dublin, and Pleasanton, California; and runoff and eroded sediment from the watersheds of Arroyo Mocho, Arroyo Las Positas and tributaries to the north (~220 sq mi). In the last three decades, population has doubled, accompanied by changing land uses in Livermore Valley. As a result, the flow of sediment and water has evolved such that, in some reaches, a combination of loss of capacity from sedimentation coupled with increased peak flows has led to channels that may not pass design flows. Previous sediment budget work by SFEI showed that the majority of sediment supply to the Alameda Flood Control Channel on the San Francisco Bay margin is supplied from the northern tributaries. SFEI's wider

  7. Airborne Survival of Rift Valley Fever Virus

    Science.gov (United States)

    1982-04-22

    Vero cells (3), and viral titers were calculated as PFU per ml. Aerosol sampling results were fitted to the simple exponential equation of the form...inoculation of Vero cell monolayers maintained in Eagle’s 3 ’ iminimal essential medium with Earle’s balanced salt solution (EMEME), supplimented with...minutes. Viable virus was identified as PFU per liter of air by plaque assay in Vero cell . Each line is the -mean of five replicate experiments. -I I I

  8. Valley Fever (Coccidioidomycosis) Risk and Prevention

    Science.gov (United States)

    ... Patients Medications that Weaken Your Immune System Outbreaks Rhizopus Investigation CDC at Work Global Fungal Diseases Cryptococcal ... laboratory, you should contact your Occupational Health, Infection Control, Risk Management, or Safety/Security Department. If your ...

  9. Rheumatic Fever

    Science.gov (United States)

    ... without the antibiotics in your bloodstream, the streptococcal bacteria can still multiply and affect your heart and other organs. If your strep infection leads to rheumatic fever, your doctor may prescribe anti-inflammatory medicines or aspirin to reduce the swelling ...

  10. Dengue fever

    African Journals Online (AJOL)

    degreasing metabolic acidosis (15). Give paracetamol for fever and analgesia. Avoid aspirin, ibuprofen and other non-steroidal anti-inflammatory agents as they may aggravate gastritis or bleeding (15). Acetylsalicylic acid (aspirin) may be associated with Reye's syndrome. Monitor patients at least 6 hourly in 24 hours.

  11. Scarlet Fever

    Centers for Disease Control (CDC) Podcasts

    2011-06-09

    Katherine Fleming-Dutra, pediatrician, discusses scarlet fever, its cause, how to treat it, and how to prevent its spread.  Created: 6/9/2011 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 6/9/2011.

  12. Orchid Fever

    Science.gov (United States)

    Oliver, Phillip

    2004-01-01

    Exotic, captivating, and seductive, orchids have long fascinated plant lovers. They first attracted the attention of Westerners in the 17th century, when explorers brought back samples from South America and Asia. By the mid-1800s, orchid collecting had reached a fever pitch, not unlike that of the Dutch tulip craze of the 1630s, with rich (and…

  13. Lassa fever

    African Journals Online (AJOL)

    ABEOLUGBENGAS

    The illness usually begins insidiously with fever, weakness, malaise joint pain or lumber pain cough and severe headache. Pharyngitis often exudative and conjunctivitis may occur early. In severe cases prostration dehydration and facial or neck oedema can occur (3). Laboratory findings include Serum aminotransferases.

  14. The ecological dichotomy of ammonia-oxidizing archaea and bacteria in the hyper-arid soils of the Antarctic Dry Valleys

    Directory of Open Access Journals (Sweden)

    Catarina Maria Magalhães

    2014-09-01

    Full Text Available The McMurdo Dry Valleys of Antarctica are considered to be one of the most physically and chemically extreme terrestrial environments on the Earth. However, little is known about the organisms involved in nitrogen transformations in these environments. In this study, we investigated the diversity and abundance of ammonia-oxidizing archaea (AOA and bacteria (AOB in four McMurdo Dry Valleys with highly variable soil geochemical properties and climatic conditions: Miers Valley, Upper Wright Valley, Beacon Valley and Battleship Promontory. The bacterial communities of these four Dry Valleys have been examined previously, and the results suggested that the extremely localized bacterial diversities are likely driven by the disparate physicochemical conditions associated with these locations. Here we showed that AOB and AOA amoA gene diversity was generally low; only four AOA and three AOB operational taxonomic units (OTUs were identified from a total of 420 AOA and AOB amoA clones. Quantitative PCR analysis of amoA genes revealed clear differences in the relative abundances of AOA and AOB amoA genes among samples from the four Dry Valleys. Although AOB amoA gene dominated the ammonia-oxidizing community in soils from Miers Valley and Battleship Promontory, AOA amoA gene were more abundant in samples from Upper Wright and Beacon Valleys, where the environmental conditions are considerably harsher (e.g., extremely low soil C/N ratios and much higher soil electrical conductivity. Correlations between environmental variables and amoA genes copy numbers, as examined by redundancy analysis (RDA, revealed that higher AOA/AOB ratios were closely related to soils with high salts and Cu contents and low pH. Our findings hint at a dichotomized distribution of AOA and AOB within the Dry Valleys, potentially driven by environmental constraints.

  15. Typhoid fever

    DEFF Research Database (Denmark)

    Wain, John; Hendriksen, Rene S.; Mikoleit, Matthew L.

    2015-01-01

    cause of enteric fever, but now S Typhi is being displaced by infections with drug-resistant S enterica serovar Paratyphi A. New conjugate vaccines are imminent and new treatments have been promised, but the engagement of local medical and public health institutions in endemic areas is needed to allow......, especially those in Africa. The main barriers to control are vaccines that are not immunogenic in very young children and the development of multidrug resistance, which threatens efficacy of antimicrobial chemotherapy. Clinicians, microbiologists, and epidemiologists worldwide need to be familiar...... with shifting trends in enteric fever. This knowledge is crucial, both to control the disease and to manage cases. Additionally, salmonella serovars that cause human infection can change over time and location. In areas of Asia, multidrug-resistant Salmonella enterica serovar Typhi (S Typhi) has been the main...

  16. [Milk fever].

    Science.gov (United States)

    Dumont, M

    1989-05-01

    Infectious complications following delivery were, in the past, attributed to "milk fever": these were milk congestion, milk deposits, rancid milk, etc., that were held responsible. The milk was reabsorbed into the blood of the patient and settled in the peritoneum ("milk peritonitis"), in the broad ligaments (pelvic abscess), in the thighs (phlebitis) and also in the breasts (breast abscess). This belief, originated by Aristotle, was accepted by excellent authors like Andre Levret (1703-1780), one of the most famous French obstetricians and Nicolas Puzos, at the same time. More recently, authors alluded to it and blamed "milk fever" for being at the origin of dramatic pictures which they described in their novels, like Victor Hugo and Guy de Maupassant, for instance.

  17. Dengue fever

    OpenAIRE

    Badreddine, Samar; Al-Dhaheri, Fahmi; Al-Dabbagh, Ammar; Al-Amoudi, Abdulrahman; Al-Ammari, Maged; Elatassi, Nader; Abbas, Haytham; Magliah,Rami; Malibari, Abdulbasit; Almoallim, Hani

    2017-01-01

    Objectives: To delineate the clinical features and outcomes of dengue infection and to guide clinician of early diagnosis and identification of risks factors for dengue hemorrhagic fever. Methods: This study is a retrospective cross-sectional. Clinical records of 567 patients with a confirmed diagnosis of dengue infection, admitted to a single hospital in Jeddah, Saudi Arabia, between January 2010 and June 2014 were reviewed. Results: Dengue infection was most common in adult males. Sixty-eig...

  18. Impacts of Climate Change at Watershed Scale: Creating an Ecological Basis for "Smart Growth" and Economic Development in the Post-industrial Lehigh Valley of Eastern PA

    Science.gov (United States)

    Holland, B.; Felzer, B.; Pazzaglia, F.; Sahagian, D.

    2009-05-01

    As modeling of global climate change matures and regional projections regarding regional variability become viable, the scales of climate impact analysis and regional decision-making begin to converge. This convergence provides a critical new challenge for both the climate modeling and policy communities- "How can projected climate change insights at watershed scale most effectively inform decisions regarding land use, zoning, and growth management?" This issue is particularly critical in regions that were formerly heavily industrialized and developed, and that are now finding new avenues for economic growth in the wake of massive clear-cutting, mining, and heavy industry of the 19th and 20th centuries. The Lehigh Valley is a watershed defining a single ecosystem that contains 800,000 people, 321 square miles of croplands and 95 square miles of urban areas, with the remainder of the watershed at various successional stages after massive forest clear-cutting of the last two centuries. Many of the industries that fueled the industrial revolution were based in the Lehigh Valley, and their development came at an environmental cost that was not then recognized, but that left a legacy of mine-scarred lands, acid mine drained streams, soil and water contamination, and a derelict industrial infrastructure that state and local governments have only recently begun to address. Before these institutions can plan for redevelopment of brownfields, regional planning for housing and commercial development, and preservation of forested and agricultural lands, it is first necessary to understand the impacts of climate change on watershed hydrology, productivity, and other ecosystems functions, and to provide this information to decision-makers responsible for environmentally sustainable development and regional planning. "Smart Growth" has become a catch phrase for regional development that is sensitive to social, economic, political, and historical goals, as well as ecological

  19. Assessment of ecological concerns with alternative water sources used for wetland maintenance at Mason Valley Wildlife Management Area, Lyon County, Nevada

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Mason Valley Wildlife Management Area in Lyon County, Nevada, obtains water from the Walker River, groundwater via fish hatchery effluent and power plant cooling...

  20. [Lassa fever].

    Science.gov (United States)

    Fleischer, K; Köhler, B; Kirchner, A; Schmid, J

    2000-06-15

    A 22-year-old female German student was admitted with fever of unknown origin for 5 days to the hospital of her hometown immediately after returning from a 7-week journey under simple conditions through 4 West African countries. After exclusion of malaria and typhoid and nonrespondence to antibiosis, she was transferred on the 4th day to the Department of Tropical Medicine in Würzburg. After the clinical assumption of Lassa fever, the virus was confirmed by PCR within 3 hours (Bernhard Nocht Institute, Hamburg) on the 10th day of her illness. The assumption was based on travel history, continuous fever, cough, pharyngitis, thoracic pain, and exclusion of other acute infections. From the beginning, the patient was cared for with barrier nursing and after diagnosis under strict isolation in an intensive care unit reserved for her alone by a team of doctors and nurses specialized in tropical medicine and intensive care. The staff was protected through isolation suits with filters. Monitoring and therapy entailed all methods of intensive care and intravenous administration of ribavirin 16 mg/kg body weight = 900 mg every 6 hours. The patient died on the 14th day of her illness in a volume deficiency shock due to uncontrollable heavy hemorrhage from all organs including the skin, a so-called "leakage syndrome". Conclusions are drawn regarding training in tropical medicine, diagnostics of highly contagious infections, intensive care of patients affected with them under isolation, contact tracing, psychological crisis intervention for personnel, media information, care of the infectious corpse and disposal of infectious waste.

  1. Context dependency and generality of fever in insects.

    Science.gov (United States)

    Stahlschmidt, Z R; Adamo, S A

    2013-07-01

    Fever can reduce mortality in infected animals. Yet, despite its fitness-enhancing qualities, fever often varies among animals. We used several approaches to examine this variation in insects. Texas field crickets (Gryllus texensis) exhibited a modest fever (1 °C increase in preferred body temperature, T pref) after injection of prostaglandin, which putatively mediates fever in both vertebrates and invertebrates, but they did not exhibit fever during chronic exposure to heat-killed bacteria. Further, chronic food limitation and mating status did not affect T pref or the expression of behavioural fever, suggesting limited context dependency of fever in G. texensis. Our meta-analysis of behavioural fever studies indicated that behavioural fever occurs in many insects, but it is not ubiquitous. Thus, both empirical and meta-analytical results suggest that the fever response in insects 'is widespread, although certainly not inevitable' (Moore 2002). We highlight the need for future work focusing on standardizing an experimental protocol to measure behavioural fever, understanding the specific mechanism(s) underlying fever in insects, and examining whether ecological or physiological costs often outweigh the benefits of fever and can explain the sporadic nature of fever in insects.

  2. Rat-bite fever

    Science.gov (United States)

    ... dwellings may help prevent rat-bite fever. Taking antibiotics by mouth after a rat bite may also help prevent this illness. Alternative Names Streptobacillary fever; Streptobacillosis; Haverhill fever; Epidemic arthritic ...

  3. Dengue Fever Testing

    Science.gov (United States)

    ... Links Patient Resources For Health Professionals Subscribe Search Dengue Fever Testing Send Us Your Feedback Choose Topic ... Images View Sources Ask Us Also Known As Dengue Fever Antibodies Dengue Fever Virus Formal Name Dengue ...

  4. Dengue Fever Treatment

    Science.gov (United States)

    ... with facebook share with twitter share with linkedin Dengue Fever Treatment Dengue Fever Dengue Fever Biology and Transmission Prevention Diagnosis ... of genomic data, and advances the understanding and treatment of dengue disease. Content last reviewed on February 7, 2011 ...

  5. Viral Hemorrhagic Fevers

    Science.gov (United States)

    ... 4 viruses that cause two other hemorrhagic fevers, dengue hemorrhagic fever and yellow fever. Virus Families Information ... 2014 Content source: Centers for Disease Control and Prevention National Center for Emerging and Zoonotic Infectious Diseases ( ...

  6. Spring migration ecology of the mid-continent sandhill crane population with an emphasis on use of the Central Platte River Valley, Nebraska

    Science.gov (United States)

    Krapu, Gary L.; Brandt, David A.; Kinzel, Paul J.; Pearse, Aaron T.

    2014-01-01

    We conducted a 10-year study (1998–2007) of the Mid-Continent Population (MCP) of sandhill cranes (Grus canadensis) to identify spring-migration corridors, locations of major stopovers, and migration chronology by crane breeding affiliation (western Alaska–Siberia [WA–S], northern Canada–Nunavut [NC–N], west-central Canada–Alaska [WC–A], and east-central Canada–Minnesota [EC–M]). In the Central Platte River Valley (CPRV) of Nebraska, we evaluated factors influencing staging chronology, food habits, fat storage, and habitat use of sandhill cranes. We compared our findings to results from the Platte River Ecology Study conducted during 1978–1980. We determined spring migration corridors used by the breeding affiliations (designated subpopulations for management purposes) by monitoring 169 cranes marked with platform transmitter terminals (PTTs). We also marked and monitored 456 cranes in the CPRV with very high frequency (VHF) transmitters to evaluate length and pattern of stay, habitat use, and movements. An estimated 42% and 58% of cranes staging in the CPRV were greater sandhill cranes (G. c. tabida) and lesser sandhill cranes (G. c. canadensis), and they stayed for an average of 20 and 25 days (2000–2007), respectively. Cranes from the WA–S, NC–N, WC–A, and EC–M affiliations spent an average of 72, 77, 52, and 53 days, respectively, in spring migration of which 28, 23, 24, and 18 days occurred in the CPRV. The majority of the WA–S subpopulation settled in the CPRV apparently because of inadequate habitat to support more birds upstream, although WA–S cranes accounted for >90% of birds staging in the North Platte River Valley. Crane staging duration in the CPRV was negatively correlated with arrival dates; 92% of cranes stayed >7 days. A program of annual mechanical removal of mature stands of woody growth and seedlings that began in the early 1980s primarily in the main channel of the Platte River has allowed distribution of crane

  7. Ecological aspects of mosquitoes (Diptera: Culicidae in the gallery forest of Brasilia National Park, Brazil, with an emphasis on potential vectors of yellow fever

    Directory of Open Access Journals (Sweden)

    Ana Raquel Lira-Vieira

    2013-10-01

    Full Text Available Introduction We analyzed the vertical and monthly distributions of culicid species in the gallery forest of Brasília National Park, with an emphasis on the potential vectors of yellow fever (YF. Methods Between September 2010 and August 2011, mosquitoes were captured on the ground and in the canopy of the forest for five consecutive days per month, from nine to 15 hours. The mosquitoes were examined to verify natural infection with flaviviruses by isolation in Aedes albopictus Skuse, 1864 cells followed by indirect immunofluorescence. Results We identified 2,677 culicids distributed in 29 species. Most of the mosquitoes were captured at ground level (69% during the rainy season (86%. The most abundant species were Sabethes (Sabethes albiprivus Theobald, 1903; Limatus durhamii Theobald, 1901; Haemagogus (Conopostegus leucocelaenus Dyar & Shannon, 1924; Haemagogus (Haemagogus janthinomys Dyar, 1921; Aedes (Ochlerotatus scapularis Rondani, 1848; Psorophora (Janthinosoma ferox Von Humboldt, 1819; and Aedes (Ochlerotatus serratus Theobald, 1901. Limatus durhamii, Limatus durhamii, Psorophora ferox, Aedes scapularis and Aedes serratus showed significant differences (p<0.05 in their habitat use. Limatus durhamii was found more often in the canopy, unlike the other species. During the rainy season, the most abundant species were Sa. albiprivus, Haemagogus leucocelaenus and Limatus durhamii. During the dry season, the potential YF vectors exhibited a very low frequency and abundance, except Aedes scapularis and Aedes serratus. No flavivirus was detected in the 2,677 examined mosquitoes. Conclusions We recommend continued and systematic entomological monitoring in areas vulnerable to the transmission of YF in the Federal District of Brazil.

  8. The Influence of Body Condition on the Stopover Ecology of Least Sandpipers in the Lower Mississippi Alluvial Valley during Fall Migration

    Directory of Open Access Journals (Sweden)

    Sarah E. Lehnen

    2007-12-01

    Full Text Available Many shorebirds are long-distance migrants and depend on the energy gained at stopover sites to complete migration. Competing hypotheses have described strategies used by migrating birds; the energy-selection hypothesis predicts that shorebirds attempt to maximize energy gained at stopover sites, whereas the time-selection hypothesis predicts that shorebirds attempt to minimize time spent at stopover sites. The energy- and time-selection hypotheses both predict that birds in better condition will depart sites sooner. However, numerous studies of stopover duration have found little support for this prediction, leading to the suggestion that migrating birds operate under energy and time constraints for only a small portion of the migratory season. During fall migration 2002, we tested the prediction that birds in better condition depart stopover sites sooner by examining the relationship between stopover duration and body condition for migrating Least Sandpipers (Calidris minutilla at three stopover sites in the Lower Mississippi Alluvial Valley. We also tested the assumption made by the Lower Mississippi Alluvial Valley Migratory Bird Science Team that shorebirds stay in the Mississippi Valley for 10 d. The assumption of 10 d was used to estimate the amount of habitat required by shorebirds in the Mississippi Valley during fall migration; a period longer than 10 d would increase the estimate of the amount habitat required. We used multiple-day constancy models of apparent survival and program MARK to estimate stopover duration for 293 individually color-marked and resighted Least Sandpipers. We found that a four-day constancy interval and a site x quadratic time trend interaction term best modeled apparent survival. We found only weak support for body condition as a factor explaining length of stopover duration, which is consistent with findings from similar work. Stopover duration estimates were 4.1 d (95% CI = 2.8-6.1 for adult Least Sandpipers

  9. The influence of climatic factors on the development of hemorrhagic fever with renal syndrome and leptospirosis during the peak season in Korea: an ecologic study.

    Science.gov (United States)

    Joshi, Yadav Prasad; Kim, Eun-Hye; Cheong, Hae-Kwan

    2017-06-07

    Hemorrhagic fever with renal syndrome (HFRS) and leptospirosis are seasonal rodent-borne infections in the Republic of Korea (Korea). The occurrences of HFRS and leptospirosis are influenced by climatic variability. However, few studies have examined the effects of local climatic variables on the development of these infections. The purpose of this study was to estimate the effect of climatic factors on the occurrence of HFRS and leptospirosis in Korea. Daily records on human cases of HFRS and leptospirosis between January 2001 to December 2009 were analyzed. The associations of climatic factors with these cases in high incidence provinces were estimated using the time-series method and multivariate generalized linear Poisson models with a maximal lag of 12 weeks. From 2001 to 2009, a total of 2912 HFRS and 889 leptospirosis cases were reported, with overall incidences of 0.67 and 0.21 cases per 100,000, respectively, in the study areas. The increase in minimum temperature (1 °C) at a lag of 11 weeks was associated with 17.8% [95% confidence interval (CI): 15.1, 20.6%] and 22.7% (95% CI: 16.5, 29.3%) increases in HFRS and leptospirosis cases, respectively. A 1-h increase in the daily sunshine was related to a 27.5% (95% CI: 18.2, 37.6%) increase in HFRS at a lag of 0 week. A 1% increase in daily minimum relative humidity and a 1 mm increase in daily rainfall were associated with 4.0% (95% CI:1.8, 6.1) and 2.0% (95% CI: 1.2, 2.8%) increases in weekly leptospirosis cases at 11 and 6 weeks later, respectively. A 1 mJ/m(2) increase in daily solar radiation was associated with a 13.7% (95% CI: 4.9, 23.2%) increase in leptospirosis cases, maximized at a 2-week lag. During the peak season in Korea, climatic factors play a significant role in the development of HFRS and leptospirosis. The findings of this study may be applicable to the forecasting and prediction of disease outbreaks.

  10. Ecological and socio-cultural factors influencing plant management in N?huatl communities of the Tehuac?n Valley, Mexico

    OpenAIRE

    Blancas, Jos?; Casas, Alejandro; P?rez-Salicrup, Diego; Caballero, Javier; Vega, Ernesto

    2013-01-01

    Background Management types and their intensity may vary according to indicators such as: (1) practices complexity, (2) degree of techniques specialization, (3) occurrence and types of social regulations, (4) artificial selection intensity, (5) energy invested, (6) tools types, and (7) amounts of resources obtained. Management types of edible plants were characterized and analyzed in N?huatl communities of the Tehuac?n Valley. We expected that both natural and human pressures generate risk on...

  11. Agritourism in Italy and the Local Impact Referring To Itria Valley. The Organic Firm “Raggio Verde” And Its Ecological Agritourism Project

    National Research Council Canada - National Science Library

    Margerita Ciervo

    2013-01-01

    ... and considering the case of study of the organic firm “Raggio Verde” in Cisternino (Brindisi, Italy) with its project of multifunctional initiatives through the creation of an organic ecological agritourism...

  12. Agritourism in Italy and the Local Impact Referring To Itria Valley. The Organic Firm "Raggio Verde" And Its Ecological Agritourism Project

    National Research Council Canada - National Science Library

    Margerita Ciervo

    2013-01-01

    ... and considering the case of study of the organic firm "Raggio Verde" in Cisternino (Brindisi, Italy) with its project of multifunctional initiatives through the creation of an organic ecological agritourism...

  13. Arbovirus infections and viral haemorrhagic fevers in Uganda: a serological survey in Karamoja district, 1984.

    Science.gov (United States)

    Rodhain, F; Gonzalez, J P; Mercier, E; Helynck, B; Larouze, B; Hannoun, C

    1989-01-01

    Sera collected in May 1984 from 132 adult residents of Karamoja district, Uganda, were examined by haemagglutination inhibition tests for antibodies against selected arboviruses, namely Chikungunya and Semliki Forest alphaviruses (Togaviridae); dengue type 2, Wesselsbron, West Nile, yellow fever and Zika flaviviruses (Flaviviridae); Bunyamwera, Ilesha and Tahyna bunyaviruses (Bunyaviridae); and Sicilian sandfly fever phlebovirus (Bunyaviridae); and by immunofluorescence tests against certain haemorrhagic fever viruses, Lassa fever arenavirus (Arenaviridae), Ebola-Sudan, Ebola-Zaïre and Marburg filoviruses (Filoviridae), Crimean-Congo haemorrhagic fever nairovirus and Rift Valley fever phlebovirus (Bunyaviridae). Antibodies against Chikungunya virus were the most prevalent (47%), followed by flavivirus antibodies (16%), which were probably due mainly to West Nile virus. No evidence of yellow fever or dengue virus circulation was observed. A few individuals had antibodies against Crimean-Congo haemorrhagic fever, Lassa, Ebola and Marburg viruses, suggesting that these viruses all circulate in the area.

  14. Familial Mediterranean Fever

    Science.gov (United States)

    ... fever usually begin during childhood. They occur in bouts called attacks that last one to three days. ... Mediterranean fever isn't treated. Complications can include: Abnormal protein in the blood. During attacks of familial ...

  15. Q fever - early

    Science.gov (United States)

    ... fever is usually noticed while looking for the cause of pneumonia . ... In rare cases, Q fever causes a heart infection that can lead to ... ) Liver infection (chronic hepatitis) Lung infection ( pneumonia )

  16. Q fever in Greenland

    DEFF Research Database (Denmark)

    Koch, Anders; Svendsen, Claus Bo; Christensen, Jens Jorgen

    2010-01-01

    We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection.......We report a patient with Q fever endocarditis in a settlement in eastern Greenland (Isortoq, Ammassalik area). Likely animal sources include sled dogs and seals. Q fever may be underdiagnosed in Arctic areas but may also represent an emerging infection....

  17. Organic mixed farms in the landscape of a brook valley. How can a co-operative of organic farms contribute to ecological and aesthetic qualities of a landscape?

    NARCIS (Netherlands)

    Kuiper, J.

    1997-01-01

    Under which conditions would an organic mixed farm co-operative contribute to the aesthetic and ecological quality of the landscape? The orientation of people in space and time is considered an important aspect of aesthetic quality. To facilitate orientation in space and time a landscape should

  18. HEMORRHAGIC-FEVER VIRUS-INFECTIONS IN AN ISOLATED RAIN-FOREST AREA OF CENTRAL LIBERIA - LIMITATIONS OF THE INDIRECT IMMUNOFLUORESCENCE SLIDE TEST FOR ANTIBODY SCREENING IN AFRICA

    NARCIS (Netherlands)

    van der Waals, F. W.; Pomeroy, K. L.; Goudsmit, J.; Asher, D. M.; Gajdusek, D. C.

    1986-01-01

    Serum samples from 119 healthy individuals and 106 epilepsy patients inhabiting Grand Bassa County, Liberia, were tested for antibodies to hemorrhagic fever viruses (HFV) by indirect immunofluorescence. E6 Vero cells infected with Lassa fever virus (LAS), Rift Valley Fever virus (RVF), Congo

  19. Determinantes de la transmisión de dengue en Veracruz: un abordaje ecológico para su control Dengue fever transmission in Veracruz, Mexico: an ecological approach to disease control

    Directory of Open Access Journals (Sweden)

    Javier Escobar-Mesa

    2003-01-01

    included data for 1,249 localities within the 11 Health Jurisdictions of the State of Veracruz, Mexico, for the 1995-1998 period. The following data were collected for each locality: total number of cases per year, population by sex, number of households, provision of public services, altitude, latitude, longitude, and deprivation index. RESULTS: Dengue transmission was registered in 17% of the localities in the State; 70% of the cases were concentrated in only 6% of the localities. Recurrent localities were urban centers with adequate availability of public services and low deprivation indices. Dengue transmission was detected in rural areas, but it was not common. The average number of cases differed according to the size of the locality and the number of years dengue was reported. A population threshold to maintain transmission was found. CONCLUSION: Recurrent localities concentrating 70% of dengue fever cases were identified, as well as the ecological and demographic factors associated with dengue transmission. The risk stratification approach to dengue transmission may improve control and prevention of this disease in high-risk areas.

  20. Recurrent fever in children

    OpenAIRE

    Sofia Torreggiani; Giovanni Filocamo; Susanna Esposito

    2016-01-01

    Children presenting with recurrent fever may represent a diagnostic challenge. After excluding the most common etiologies, which include the consecutive occurrence of independent uncomplicated infections, a wide range of possible causes are considered. This article summarizes infectious and noninfectious causes of recurrent fever in pediatric patients. We highlight that, when investigating recurrent fever, it is important to consider age at onset, family history, duration of febrile episodes,...

  1. Feeding ecology of Bornean orangutans (Pongo pygmaeus morio) in Danum Valley, Sabah, Malaysia: a 3-year record including two mast fruitings.

    Science.gov (United States)

    Kanamori, Tomoko; Kuze, Noko; Bernard, Henry; Malim, Titol P; Kohshima, Shiro

    2010-09-01

    We observed the diet and activity of Bornean orangutans (Pongo pygmaeus morio) in the primary lowland dipterocarp forests of Danum Valley, Sabah, Malaysia, during 2005-2007, including two mast fruitings. We collected 1,785 hr of focal data on 26 orangutans. We identified 1,466 samples of their food plants and conducted a fallen fruit census to monitor fruit availability in the study area. Their activity budget was 47.2% feeding, 34.4% resting, and 16.9% traveling. Fruits accounted for the largest part (60.9%) of feeding time, especially during mast fruiting periods (64.0-100%), although the percentages of leaves (22.2%) and bark (12.3%) were higher than those reported for P. abelii and P. pygmaeus wurmbii. Although 119 genera and 160 plant species were consumed by focal animals, only 9 genera accounted for more than 3% of feeding time (total: 67.8% for 9 genera). In particular, the focal orangutans fed intensively on Ficus and Spatholobus during most of the study period, especially in periods of fruit shortage. The percentage of fruit feeding changed markedly from 11.7 to 100% across different months of the year, and was positively correlated with the amount of fallen fruit. When fruit feeding and availability decreased, orangutans fed primarily on leaves of Spatholobus and Ficus, and the bark of Spatholobus and dipterocarp. The percentage of time devoted to feeding during mast fruitings, when the orangutans foraged almost exclusively on fruits, was lower than during seasons when the orangutan diet included leaves and bark as well as fruits. Resting increased as feeding decreased in the late stage of each fruiting season, suggesting that the orangutans adopted an energy-minimizing strategy to survive the periods of fruit shortage by using energy stored during the fruit season. (c) 2010 Wiley-Liss, Inc.

  2. Veronica longifolia L. as an important initial larval food plant of Scarce Fritillary Euphydryas maturna (LINNAEUS, 1758 (Lepidoptera, Nymphalidae: the ecological uniqueness of populations from the Natura 2000 area “Dolina Biebrzy” (Biebrza Valley in NE Poland

    Directory of Open Access Journals (Sweden)

    Sielezniew Marcin

    2016-06-01

    Full Text Available The Euro-Siberian Scarce Fritillary Euphydryas maturna is considered a vulnerable species in the European Union and is listed in Annexes II and IV of the Habitats Directive. The butterfly shows a complex pattern of larval plant use throughout its range. In central Europe females oviposit on some trees and bushes, especially Fraxinus spp., on which hatched larvae spend their pre-diapause phase of development feeding gregariously in conspicuous webs. However, some herbal plants are also reported in the north and east. During a study performed in the Natura 2000 area “Dolina Biebrzy” (Biebrza Valley in NE Poland we recorded populations showing a unique mixture of ecological characteristics. Both Fraxinus excelsior and Veronica longifolia were used as larval food plants before hibernation, and some local populations seemed to be completely dependent on the latter plant. Moreover, in the spring, at one site, we observed larvae feeding on Salix rosmarinifolia - the first host record for this plant species. The importance of our findings for conservation, as well as for the monitoring of the butterfly, is discussed.

  3. Marburg Hemorrhagic Fever (Marburg HF)

    Science.gov (United States)

    ... Submit Search the CDC Marburg hemorrhagic fever (Marburg HF) Note: Javascript is disabled or is not supported ... Fever (VHF) Information for Specific Groups, References... Marburg HF Outbreak Distribution Map Factsheet: Marburg Hemorrhagic Fever [PDF – ...

  4. Q Fever: Statistics and Epidemiology

    Science.gov (United States)

    ... Other Spotted Fever Rocky Mountain Spotted Fever More Epidemiology and Statistics Recommend on Facebook Tweet Share Compartir ... in 2007. In 2008, the Q fever case definition was changed to allow for the reporting of ...

  5. Rat Bite Fever

    Science.gov (United States)

    ... Issues Listen Español Text Size Email Print Share Rat Bite Fever Page Content Article Body Rat-bite fever is a disease that occurs in humans who have been bitten by an infected rat or, in some cases, squirrels, mice, cats, and ...

  6. African tick bite fever

    DEFF Research Database (Denmark)

    Johansen, Jakob Aaquist; Thybo, Søren

    2011-01-01

    The incident of spotted fever imported to Denmark is unknown. We present a classic case of African Tick Bite Fever (ATBF) to highlight a disease, which frequently infects wildlife enthusiasts and hunters on vacation in South Africa. ATBF has a good prognosis and is easily treated with doxycyclin...

  7. VIRAL FEVER WITH THROMBOCYTOPENIA

    OpenAIRE

    Shilpa Anand Hakki

    2017-01-01

    BACKGROUND There is an alarming increase in the incidence of fever with thrombocytopenia especially during monsoon and peri-monsoon period. Infections with protozoa, bacteria and viruses can cause thrombocytopenia with or without disseminated intravascular coagulation. Commonly, dengue, malaria, scrub typhus and other rickettsial infections, meningococci, Leptospira and certain viral infections present as fever with thrombocytopenia. Occasionally, these patients can go on to devel...

  8. Behavioural ecology of captive otters Lutra lutra in the Breeding Centre of the Natural Park of Ticino Valley (Piemonte Region, Northern Italy

    Directory of Open Access Journals (Sweden)

    Renato Fumagalli

    1995-12-01

    Full Text Available Abstract The study was conducted on a pair of otters (Lutra lutra housed in an enclosure of 1.64 ha, located within a wet wood in the Natural Park of the Ticino Valley (northern Italy, Piemonte region. This enclosure contained two ponds (0.2 and 0.45 ha with fairly good cover vegetation, where a fish biomass of 201.5 kg/ha, represented by 14 fish species, was assessed by electrofishing. Though the food supply for otter was fairly good, the animals were daily fed with 1.5 kg of chicks, meat or rainbow trout (Salmo gairdneri. In order to evaluate the habitat selection of otters, the enclosure was divided into 15 environmental units (EU. Hunting, swimming and playing (exclusively in pair were the main behavioural activities and were preferentially performed close to the ponds' bank, where a thick cover occurred. Otters selected patches for foraging where fish was concentrated and particularly vulnerable to predation. The hunting impact in a given EU (defined as ratio between the number of prey caught in the EU and the total number of prey was correlated with the hunting time spent in the same EU. Habitat use evaluated by direct observations differed from that determined by considering the marking level (number of spraints and anal secretions. The consumption of the different fish species did not seem to be determined by their relative abundance. Perca fluviatilis was particularly selected. Riassunto Ecologia comportamentale della lontra Lutra lutra nel centro di studio del Parco Naturale della Valle del Ticino (Regione Piemonte - Lo studio è stato condotto su una coppia di lontra (Lutra lutra tenuta in un ampio recinto (1.64 ha, situato nel Parco Naturale della Valle del Ticino (Regione Piemonte, Provincia di Novara. L'area cintata è ritagliata all'interno di un bosco planiziale e comprende 2 bacini idrici (0,2 e 0,4 ha bordati da discreta copertura

  9. Ecological Study of Periphytic Algal Community of Doodh Ganga and Khansha-Mansha Streams of Yusmarg Forests: A Health Resort of Kashmir Valley, India

    Directory of Open Access Journals (Sweden)

    Rafia Rashid

    2013-06-01

    Full Text Available The present study on Doodh Ganga and Khansha-Mansha streams of Yusmarg forests deals with the general ecological studies on periphytic algal community in terms of species composition and density. During the present investigation the periphytic algal community of Doodh Ganga and Khansha-Mansha streams were represented by 30 taxa which belonged to 4 major classes namely Bacillariophyceae (14, Chlorophyceae (11, Cyanophyceae (4 and Euglenophyceae (1. The most common periphytic species encountered across all the sites included Closterium sp., Zygnema sp., Amphora sp., Cymbella sp., Epithemia sp., Fragilaria sp., Navicula sp., Synedra sp., Tabellaria sp., Lyngbya sp. and Phormidium sp. Among the two streams, Doodh Ganga showed large number of taxa (45 and Khansha-Mansha was having 37 taxa of periphyton. Bacillariophyceae was the dominant group both in diversity and density and included 14 taxa contributing 57% of total periphytic algal population. Cyanophyceae forming the second dominant class was represented by 4 genera comprising 22% of the total periphytic algae .Chlorophyceae ranked third in its dominance pattern with 11 genera forming 20% of all the periphytic algae. Euglenophyceae was represented by only one species of Euglena sp. forming 1% of all the periphytic algae and found only at site 2 (Doodh Ganga downstream.Amongst the study sites the highest (5.69 value of Shannon Weiner Index was found at Doodh Ganga upstream while as lowest (4.38 at Khansha-Mansha downstream. The primary conclusion is that the streams, having crystal clear water, and are free from pollution as Chlorophyceae are better represented in both the streams. Further, as a result of less anthropogenic pressures the quality of water is fairly good.

  10. Yellow fever cases in Asia: primed for an epidemic

    Directory of Open Access Journals (Sweden)

    Sean Wasserman

    2016-07-01

    Full Text Available There is currently an emerging outbreak of yellow fever in Angola. Cases in infected travellers have been reported in a number of other African countries, as well as in China, representing the first ever documented cases of yellow fever in Asia. There is a large Chinese workforce in Angola, many of whom may be unvaccinated, increasing the risk of ongoing importation of yellow fever into Asia via busy commercial airline routes. Large parts of the region are hyperendemic for the related Flavivirus dengue and are widely infested by Aedes aegypti, the primary mosquito vector of urban yellow fever transmission. The combination of sustained introduction of viraemic travellers, an ecology conducive to local transmission, and an unimmunized population raises the possibility of a yellow fever epidemic in Asia. This represents a major global health threat, particularly in the context of a depleted emergency vaccine stockpile and untested surveillance systems in the region. In this review, the potential for a yellow fever outbreak in Asia is discussed with reference to the ecological and historical forces that have shaped global yellow fever epidemiology. The limitations of surveillance and vector control in the region are highlighted, and priorities for outbreak preparedness and response are suggested.

  11. Yellow fever cases in Asia: primed for an epidemic.

    Science.gov (United States)

    Wasserman, Sean; Tambyah, Paul Anantharajah; Lim, Poh Lian

    2016-07-01

    There is currently an emerging outbreak of yellow fever in Angola. Cases in infected travellers have been reported in a number of other African countries, as well as in China, representing the first ever documented cases of yellow fever in Asia. There is a large Chinese workforce in Angola, many of whom may be unvaccinated, increasing the risk of ongoing importation of yellow fever into Asia via busy commercial airline routes. Large parts of the region are hyperendemic for the related Flavivirus dengue and are widely infested by Aedes aegypti, the primary mosquito vector of urban yellow fever transmission. The combination of sustained introduction of viraemic travellers, an ecology conducive to local transmission, and an unimmunized population raises the possibility of a yellow fever epidemic in Asia. This represents a major global health threat, particularly in the context of a depleted emergency vaccine stockpile and untested surveillance systems in the region. In this review, the potential for a yellow fever outbreak in Asia is discussed with reference to the ecological and historical forces that have shaped global yellow fever epidemiology. The limitations of surveillance and vector control in the region are highlighted, and priorities for outbreak preparedness and response are suggested. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  12. Lithotrites and postoperative fever

    DEFF Research Database (Denmark)

    Chu, David I; Lipkin, Michael E; Wang, Agnes J

    2013-01-01

    OBJECTIVE: To compare the risks of fever from different lithotrites after percutaneous nephrolithotomy (PNL). MATERIALS AND METHODS: The Clinical Research Office of the Endourological Society (CROES) PNL database is a prospective, multi-institutional, international PNL registry. Of 5,803 total...... with fever [Odds Ratio (OR) 1.17, p = 0.413], while diabetes (OR 1.32, p = 0.048), positive urine culture (OR 2.08, p PNL...... fever was not significantly different among the various lithotrites used in the CROES PNL study....

  13. Travelers' Health: Yellow Fever

    Science.gov (United States)

    ... Books, Journals, Articles & Websites Resources for the Travel Industry Yellow Book Contents Chapter 3 (83) Yellow Fever ... should be taken to avoid medications, such as aspirin or nonsteroidal anti-inflammatory drugs, which may increase ...

  14. The Fever Effect

    OpenAIRE

    Milton, Damian

    2016-01-01

    In episode 4 of ‘The A word’, Jo, the young Autistic child depicted in the series has a fever, during which he shows more signs or reciprocal communication and empathy. Whilst it is mentioned in this program that there have been studies in to the ‘fever effect’, in fact there have not been in-depth scientific studies carried out on this phenomenon.

  15. [Dengue fever: clinical features].

    Science.gov (United States)

    Dellamonica, P

    2009-10-01

    The vector for dengue fever and chikungunya, Aedes albopictus, was recently identified in Southeastern France, although the usual vector for dengue fever is Aedes aegypti, raising the possibility of cases occurring among the local population via viraemic individuals returning from endemic areas. Dengue fever is usually transmitted by Aedes aegypti. It is due to an arbovirus-flavivirus of which four different serotypes are known: Den 1 to 4. Each serotype is responsible for specific prolonged immunity but no cross-reactivity exists between serotypes. Clinically, the onset is abrupt with frontal headache, retro-orbital pain, myalgia, joint pain, prostration and, in many cases, a macular rash usually sparing the face and extremities. Haemorrhagic signs may occur, such as petechiae, purpura, epistaxis or bleeding gingivae. Two severe forms of dengue fever, particularly among children below 3 years of age, include dengue haemorrhagic fever (DHF) and DHF with shock (dengue shock syndrome). If a case is suspected in metropolitan France, the diagnosis should be systematically confirmed by positive specific IgM, RT-PCR or viral isolation. Treatment of dengue fever, whether in its uncomplicated form or with hemorrhagic manifestations or shock, remains symptomatic. There is no specific anti-viral treatment. A case should be notified to allow French health authorities to take the appropriate measures for vector control.

  16. Range management research, Fort Valley Experimental Forest

    Science.gov (United States)

    Henry A. Pearson; Warren P. Clary; Margaret M. Moore; Carolyn Hull Sieg

    2008-01-01

    Range management research at the Fort Valley Experimental Forest during the past 100 years has provided scientific knowledge for managing ponderosa pine forests and forest-range grazing lands in the Southwest. Three research time periods are identified: 1908 to 1950, 1950 to 1978, and 1978 to 2008. Early research (1908-1950) addressed ecological effects of livestock...

  17. Recurrent Fever in Children

    Directory of Open Access Journals (Sweden)

    Sofia Torreggiani

    2016-03-01

    Full Text Available Children presenting with recurrent fever may represent a diagnostic challenge. After excluding the most common etiologies, which include the consecutive occurrence of independent uncomplicated infections, a wide range of possible causes are considered. This article summarizes infectious and noninfectious causes of recurrent fever in pediatric patients. We highlight that, when investigating recurrent fever, it is important to consider age at onset, family history, duration of febrile episodes, length of interval between episodes, associated symptoms and response to treatment. Additionally, information regarding travel history and exposure to animals is helpful, especially with regard to infections. With the exclusion of repeated independent uncomplicated infections, many infective causes of recurrent fever are relatively rare in Western countries; therefore, clinicians should be attuned to suggestive case history data. It is important to rule out the possibility of an infectious process or a malignancy, in particular, if steroid therapy is being considered. After excluding an infectious or neoplastic etiology, immune-mediated and autoinflammatory diseases should be taken into consideration. Together with case history data, a careful physical exam during and between febrile episodes may give useful clues and guide laboratory investigations. However, despite a thorough evaluation, a recurrent fever may remain unexplained. A watchful follow-up is thus mandatory because new signs and symptoms may appear over time.

  18. Comparison of sampling techniques for Rift Valley Fever virus ...

    African Journals Online (AJOL)

    A total of 1814 mosquitoes were collected, of which 738 were collected by CDC light traps and 1076 by Mosquito Magnet trapping technique. Of the collected mosquitoes, 12.46% (N= 226) were Aedes aegypti and 87.54% (N= 1588) were Culex pipiens complex. More mosquitoes were collected outdoors using Mosquito ...

  19. Rift Valley Fever in Camels in Northern Burkina Faso | Boussini ...

    African Journals Online (AJOL)

    Recommendations for systematic RVF investigation in camels and others domestic ruminants were made in order to improve the animal productivity. Habitual consumption of raw milk and close contact with infected animals signify possible zoonotic importance of RVF in the studied area. A risk assessment of the disease ...

  20. Occurrence of rift valley fever (RVF) in Dodoma region, Tanzania ...

    African Journals Online (AJOL)

    While waiting for the results the patients were treated for malaria and/or meningitis based on visual/ clinical signs. However, most of the patients did not recover and the situation worsened followed by several deaths. Most of the blood samples were negative for Malaria and/or meningitis. This led to suspicion of RVF.

  1. Rift Valley Fever Virus Glycoproteins, Key to Entry and Control

    NARCIS (Netherlands)

    de Boer, S.M.

    2013-01-01

    In this thesis we have focussed on the RVFV Gn and Gc glycoproteins, the keys for virus entry and virus control. RVFV is an emerging virus that has already spread across the African continent and to the Arabian Peninsula. Outbreaks of RVFV are characterized by abortion storms and high mortality,

  2. Rift Valley fever potential mosquito vectors and their infection status ...

    African Journals Online (AJOL)

    They were tested for RVFV RNA using real time reverse transcription-polymerase chain reaction (rRT-PCR). Results: A total of 2,094 adult mosquitoes belonging to three genera and nine species were collected. Most of them (87.5%) were collected in Meshili, followed by Malambo (8.2%) and Osinoni (4%) villages.

  3. Comparison of sampling techniques for Rift Valley Fever virus ...

    African Journals Online (AJOL)

    which 738 were collected by CDC light traps and 1076 by Mosquito Magnet trapping technique. Of the collected mosquitoes, 12.46% (N= 226) were Aedes aegypti and 87.54% (N= 1588) were Culex pipiens complex. More mosquitoes were collected outdoors using Mosquito Magnets baited with octenol attractant, 36.38%.

  4. Response to Rift Valley Fever in Tanzania: Challenges and ...

    African Journals Online (AJOL)

    cattle, sheep, goats and camels), wildlife and humans caused by Phlebovirus. The disease occurs in periodic cycles of 4-15 years associated with flooding from unusually high precipitations in many flood-prone habitats. Aedes and Culex spp and ...

  5. Pathogenesis of Lassa Fever

    Directory of Open Access Journals (Sweden)

    David H. Walker

    2012-10-01

    Full Text Available Lassa virus, an Old World arenavirus (family Arenaviridae, is the etiological agent of Lassa fever, a severe human disease that is reported in more than 100,000 patients annually in the endemic regions of West Africa with mortality rates for hospitalized patients varying between 5-10%. Currently, there are no approved vaccines against Lassa fever for use in humans. Here, we review the published literature on the life cycle of Lassa virus with the specific focus put on Lassa fever pathogenesis in humans and relevant animal models. Advancing knowledge significantly improves our understanding of Lassa virus biology, as well as of the mechanisms that allow the virus to evade the host’s immune system. However, further investigations are required in order to design improved diagnostic tools, an effective vaccine, and therapeutic agents.

  6. Pathogenesis of Lassa fever.

    Science.gov (United States)

    Yun, Nadezhda E; Walker, David H

    2012-10-09

    Lassa virus, an Old World arenavirus (family Arenaviridae), is the etiological agent of Lassa fever, a severe human disease that is reported in more than 100,000 patients annually in the endemic regions of West Africa with mortality rates for hospitalized patients varying between 5-10%. Currently, there are no approved vaccines against Lassa fever for use in humans. Here, we review the published literature on the life cycle of Lassa virus with the specific focus put on Lassa fever pathogenesis in humans and relevant animal models. Advancing knowledge significantly improves our understanding of Lassa virus biology, as well as of the mechanisms that allow the virus to evade the host's immune system. However, further investigations are required in order to design improved diagnostic tools, an effective vaccine, and therapeutic agents.

  7. Familial Mediterranean Fever

    Directory of Open Access Journals (Sweden)

    Adem Kucuk

    2014-01-01

    Full Text Available Familial Mediterranean Fever is an autosomal recessive inherited disease with a course of autoinflammation, which is characterized by the episodes of fever and serositis. It affects the populations from Mediterranean basin. Genetic mutation of the disease is on MEFV gene located on short arm of Chromosome 16. The disease is diagnosed based on clinical evaluation. Amyloidosis is the most important complication. The only agent that decreases the development of amyloidosis and the frequency and severity of the episodes is colchicine, which has been used for about 40 years. In this review, we aimed to discuss especially the most recent advances about Familial Mediterranean Fever which is commonly seen in our population.

  8. Energy valley in transition

    NARCIS (Netherlands)

    Verwayen, Barbara

    2006-01-01

    The Energy Valley foundation was born in 2004. It functions as a catalyst and platform for private and public organisations. It has a supporting and facilitating role in realising projects on energy conservation and sustainable energy. The Energy Valley a

  9. Signs of scarlet fever (image)

    Science.gov (United States)

    Scarlet fever is a disease caused by an infection with group A beta-hemolytic streptococcal bacteria that occurs in a small percentage of people with strep throat. The illness typically begins with a fever and ...

  10. Borrelia miyamotoi: a widespread tick-borne relapsing fever spirochete

    NARCIS (Netherlands)

    Wagemakers, Alex; Staarink, Pieter J.; Sprong, Hein; Hovius, Joppe W. R.

    2015-01-01

    Borrelia miyamotoi is a relapsing fever spirochete that has only recently been identified as a human pathogen. Borrelia miyamotoi is genetically and ecologically distinct from Borrelia burgdorferi sensu lato, while both are present in Ixodes ticks. Over 50 patients with an acute febrile illness have

  11. Hereditary periodic fever syndromes

    NARCIS (Netherlands)

    McDermott, MF; Frenkel, J

    Hereditary periodic fever syndromes are defined by recurrent attacks of generalised inflammation for which no infectious or auto-immune cause can be identified. For most of these disorders, the molecular basis has recently been elucidated. This has opened the prospect of novel therapeutic

  12. Fever of unknown origin

    NARCIS (Netherlands)

    Mulders-Manders, C.; Simon, A.; Bleeker-Rovers, C.P.

    2015-01-01

    More than 50 years after the first definition of fever of unknown origin (FUO), it still remains a diagnostic challenge. Evaluation starts with the identification of potential diagnostic clues (PDCs), which should guide further investigations. In the absence of PDCs a standardised diagnostic

  13. Ebola haemorrhagic fever

    Science.gov (United States)

    Feldmann, Heinz; Geisbert, Thomas W

    2012-01-01

    Ebola viruses are the causative agents of a severe form of viral haemorrhagic fever in man, designated Ebola haemorrhagic fever, and are endemic in regions of central Africa. The exception is the species Reston Ebola virus, which has not been associated with human disease and is found in the Philippines. Ebola virus constitutes an important local public health threat in Africa, with a worldwide effect through imported infections and through the fear of misuse for biological terrorism. Ebola virus is thought to also have a detrimental effect on the great ape population in Africa. Case-fatality rates of the African species in man are as high as 90%, with no prophylaxis or treatment available. Ebola virus infections are characterised by immune suppression and a systemic inflammatory response that causes impairment of the vascular, coagulation, and immune systems, leading to multiorgan failure and shock, and thus, in some ways, resembling septic shock. PMID:21084112

  14. Tick-Borne Relapsing Fever Spirochetes in the Americas

    Directory of Open Access Journals (Sweden)

    Job E. Lopez

    2016-08-01

    Full Text Available Relapsing fever spirochetes are tick- and louse-borne pathogens that primarily afflict those in impoverished countries. Historically the pathogens have had a significant impact on public health, yet currently they are often overlooked because of the nonspecific display of disease. In this review, we discuss aspects of relapsing fever (RF spirochete pathogenesis including the: (1 clinical manifestation of disease; (2 ability to diagnose pathogen exposure; (3 the pathogen’s life cycle in the tick and mammal; and (4 ecological factors contributing to the maintenance of RF spirochetes in nature.

  15. Swarming Mechanisms in the Yellow Fever Mosquito: Aggregation Pheromones are Involved in the Mating Behavior of Aedes aegypti

    Science.gov (United States)

    2014-12-01

    Vol. 39, no. 2 Journal of Vector Ecology 347 Swarming mechanisms in the yellow fever mosquito: aggregation pheromones are involved in the mating...aegypti Linnaeus is one of the most medically important mosquitoes as the main vector of dengue, chikungunya, and yellow fever viruses, in addition to its...2014 to 00-00-2014 4. TITLE AND SUBTITLE Swarming Mechanisms in the Yellow Fever Mosquito: Aggregation Pheromones are Involved in the Mating

  16. Flood Frequency Analysis of Main Nara Valley

    OpenAIRE

    Manohar Lal; Bakhshal Khan Lashari; Khalifa Qasim Laghari

    2011-01-01

    This paper deals with the flood of 2007 and its frequency analysis at MNY (Main Nara Valley), and generally describe flood of 2010 in Sindh Pakistan. Heavy monsoon rain and cyclones cause the flood conditions in Sindh. The damages happened to the infrastructure of the MNVD from RD (Reduced Distance) 0-100 and the ecological impacts of the flood on the local region of Taluka Johi, District Dadu. For flood risk assessment and its description, knowledge of extreme flood events and...

  17. [Ecology and ecologies].

    Science.gov (United States)

    Valera, Luca

    2011-01-01

    Ecology (from the Greek words οιχοσ, "house" and λογια "study of") is the science of the "house", since it studies the environments where we live. There are three main ways of thinking about Ecology: Ecology as the study of interactions (between humans and the environment, between humans and living beings, between all living beings, etc.), Ecology as the statistical study of interactions, Ecology as a faith, or rather as a science that requires a metaphysical view. The history of Ecology shows us how this view was released by the label of "folk sense" to gain the epistemological status of science, a science that strives to be interdisciplinary. So, the aim of Ecology is to study, through a scientific methodology, the whole natural world, answering to very different questions, that arise from several fields (Economics, Biology, Sociology, Philosophy, etc.). The plurality of issues that Ecology has to face led, during the Twentieth-century, to branch off in several different "ecologies". As a result, each one of these new approaches chose as its own field a more limited and specific portion of reality.

  18. Ebola hemorrhagic Fever.

    Science.gov (United States)

    Burnett, Mark W

    2014-01-01

    Ebola hemorrhagic fever is an often-fatal disease caused by a virus of the Filoviridae family, genus Ebolavirus. Initial signs and symptoms of the disease are nonspecific, often progressing on to a severe hemorrhagic illness. Special Operations Forces Medical Providers should be aware of this disease, which occurs in sporadic outbreaks throughout Africa. Treatment at the present time is mainly supportive. Special care should be taken to prevent contact with bodily fluids of those infected, which can transmit the virus to caregivers. 2014.

  19. Perehdytysopas, Fashion Fever Oy

    OpenAIRE

    Schwartz-Kröger, Matilda

    2016-01-01

    Tässä toiminnallisessa opinnäytetyössä keskityttiin perehdyttämisen teoriaan ja perehdyttämisoppaan kokoamiseen. Tavoitteena oli tuottaa toimiva perehdyttämisopas Porin, Vaasan, Turun ja Seinäjoen Vila-myymälöiden tarpeisiin. Toimeksiantajana toimi Fashion Fever Oy. Perehdyttämisopas oli hyvä valinta opinnäytetyön aiheeksi, koska yritys oli kasvanut sen kokoiseksi, että kaikkien toimipisteiden rutiinit oli tärkeä yhtenäistää. Sen avulla voitiin varmistaa, että kaikki aloittavat työntekijät...

  20. California's Central Valley Groundwater Study: A Powerful New Tool to Assess Water Resources in California's Central Valley

    Science.gov (United States)

    Faunt, Claudia C.; Hanson, Randall T.; Belitz, Kenneth; Rogers, Laurel

    2009-01-01

    Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley's population has nearly doubled to 3.8 million people. It is expected to increase to 6 million by 2020. Statewide population growth, anticipated reductions in Colorado River water deliveries, drought, and the ecological crisis in the Sacramento-San Joaquin Delta have created an intense demand for water. Tools and information can be used to help manage the Central Valley aquifer system, an important State and national resource.

  1. Serological evidence of dengue fever among refugees, Hargeysa, Somalia.

    Science.gov (United States)

    Botros, B A; Watts, D M; Soliman, A K; Salib, A W; Moussa, M I; Mursal, H; Douglas, C; Farah, M

    1989-10-01

    Epidemics of a malaria-like illness affected several thousand residents of the Dam Camp, a refugee camp near Hargeysa in Somalia, during 1985, 1986, and 1987. The disease was characterized by fever, chills, sweats, headache, back and joint pains for as long as 10 days in some patients. Blood smears from acutely ill patients were negative for malaria. Of 28 acute and 10 convalescent sera tested by the indirect fluorescent antibody (IFA) and by the hemagglutination inhibition (HI) tests, all were negative for antibody to Rift Valley fever, Crimean-Congo hemorrhagic fever, Sindbis, Chikungunya, yellow fever, and Zika viruses. However, antibody reactive to dengue 2 virus was detected by the IFA test in 39% (15/38), and 11 of 29 (38%) of the same sera were antibody positive by the HI test. Also, IgG antibody reactive to dengue 2 was demonstrated in 60% (17/28) of the same sera by the enzyme immunoassay (EIA), and 14% (4/28) were positive for IgM antibody. Of ten patients for which acute and convalescent sera were available, two developed four fold or greater rises in antibody titer evidencing infection. These data suggested that dengue virus may have been the cause of the epidemic among the Dam Camp refugees.

  2. relapsing fever, a disappearing cause of fever and maternal death

    African Journals Online (AJOL)

    2013-04-01

    Apr 1, 2013 ... by various Borrelia spirochetes transmitted either by lice (epidemic relapsing fever) or ticks (endemic relapsing fever, caused by Borrelia Duttoni). Clinically, these spirochetes all produce an undulating febrile disease in humans, with signs and symptoms often indistinguishable from those of malaria (3,4) .

  3. Relapsing fever, a disappearing cause of fever and maternal death ...

    African Journals Online (AJOL)

    Objective: To study the incidence of tick borne relapsing fever (TBRF) during the last 50 years, once like malaria an endemic disease in Sengerema, Tanzania. Design: By analyzing the annual reports, focusing on the number of admissions, maternal deaths, blood smears of patients with fever for Borrelia.

  4. Silicon Valley: Planet Startup

    NARCIS (Netherlands)

    Dr. P. Ester; dr. A. Maas

    2016-01-01

    For decades now, Silicon Valley has been the home of the future. It's the birthplace of the world's most successful high-tech companies-including Apple, Yahoo, Google, Facebook, Twitter, and many more. So what's the secret? What is it about Silicon Valley that fosters entrepreneurship and

  5. Febre amarela Yellow fever

    Directory of Open Access Journals (Sweden)

    Pedro Fernando da Costa Vasconcelos

    2003-04-01

    Full Text Available A febre amarela é doenca infecciosa não-contagiosa causada por um arbovírus mantido em ciclos silvestres em que macacos atuam como hospedeiros amplificadores e mosquitos dos gêneros Aedes na África, e Haemagogus e Sabethes na América, são os transmissores. Cerca de 90% dos casos da doença apresentam-se com formas clínicas benignas que evoluem para a cura, enquanto 10% desenvolvem quadros dramáticos com mortalidade em torno de 50%. O problema mostra-se mais grave em África onde ainda há casos urbanos. Nas Américas, no período de 1970-2001, descreveram-se 4.543 casos. Os países que mais diagnosticaram a doença foram o Peru (51,5%, a Bolívia (20,1% e o Brasil (18,7%. Os métodos diagnósticos utilizados incluem a sorologia (IgM, isolamento viral, imunohistoquímica e RT-PCR. A zoonose não pode ser erradicada, mas, a doença humana é prevenível mediante a vacinação com a amostra 17D do vírus amarílico. A OMS recomenda nova vacinação a cada 10 anos. Neste artigo são revistos os principais conceitos da doença e os casos de mortes associados à vacina.Yellow fever is an infectious and non-contagious disease caused by an arbovirus, the yellow fever virus. The agent is maintained in jungle cycles among primates as vertebrate hosts and mosquitoes, especially Aedes in Africa, and Haemagogus and Sabethes in America. Approximately 90% of the infections are mild or asymptomatic, while 10% course to a severe clinical picture with 50% case-fatality rate. Yellow fever is largely distributed in Africa where urban epidemics are still reported. In South America, between 1970-2001, 4,543 cases were reported, mostly from Peru (51.5%, Bolivia (20.1% and Brazil (18.7%. The disease is diagnosed by serology (detection of IgM, virus isolation, immunohistochemistry and RT-PCR. Yellow fever is a zoonosis and cannot be eradicated, but it is preventable in man by using the 17D vaccine. A single dose is enough to protect an individual for at least

  6. Q fever: the Dutch policy

    NARCIS (Netherlands)

    Bruschke, C. J. M.; Roest, H. I. J.; Coutinho, R. A.

    2016-01-01

    Between 2007 and 2010, the Netherlands experienced an unprecedented outbreak of Q fever of more than 4000 human cases. Q fever infections of dairy goats, leading to abortion waves, were considered to be the cause of this outbreak. Measures to combat the outbreak had to be taken based on limited

  7. Q fever: The Dutch Policy

    NARCIS (Netherlands)

    Bruschke, C.J.M.; Roest, H.I.J.; Coutinho, R.A.

    2016-01-01

    Between 2007 and 2010, the Netherlands experienced an unprecedented outbreak of Q fever of more than 4000 human cases. Q fever infections of dairy goats, leading to abortion waves, were considered to be the cause of this outbreak. Measures to combat the outbreak had to be taken based on limited

  8. Borrelia hispanica Relapsing Fever, Morocco

    Science.gov (United States)

    Sarih, M’hammed; Garnier, Martine; Boudebouch, Najma; Bouattour, Ali; Rihani, Abdelaziz; Hassar, Mohammed; Gern, Lise; Postic, Danièle

    2009-01-01

    We found that 20.5% of patients with an unexplained fever in northwestern Morocco had tick-borne relapsing fever. Molecular detection specific for the 16S rRNA gene identified Borrelia hispanica. The noncoding intergenic spacer sequence domain showed high sensitivity and good resolution for this species. PMID:19861058

  9. Pathogens, disease, and the social-ecological resilience of protected areas

    Directory of Open Access Journals (Sweden)

    Alta De Vos

    2016-03-01

    Full Text Available It is extremely important for biodiversity conservation that protected areas are resilient to a range of potential future perturbations. One of the least studied influences on protected area resilience is that of disease. We argue that wildlife disease (1 is a social-ecological problem that must be approached from an interdisciplinary perspective; (2 has the potential to lead to changes in the identity of protected areas, possibly transforming them; and (3 interacts with conservation both directly (via impacts on wild animals, livestock, and people and indirectly (via the public, conservation management, and veterinary responses. We use southern African protected areas as a case study to test a framework for exploring the connections between conservation, endemic disease, and social-ecological resilience. We first define a set of criteria for the social-ecological identity of protected areas. We then use these criteria to explore the potential impacts of selected diseases (foot-and-mouth disease, anthrax, malaria, rabies, rift valley fever, trypanosomiasis, and canine distemper on protected area resilience. Although endemic diseases may have a number of direct impacts on both wild animals and domestic animals and people, the indirect pathways by which diseases influence social-ecological resilience also emerge as potentially important. The majority of endemic pathogens found in protected areas do not kill large numbers of wild animals or infect many people, and may even play valuable ecological roles; but occasional disease outbreaks and mortalities can have a large impact on public perceptions and disease management, potentially making protected areas unviable in one or more of their stated aims. Neighboring landowners also have a significant impact on park management decisions. The indirect effects triggered by disease in the human social and economic components of protected areas and surrounding landscapes may ultimately have a greater

  10. Comparison of plant cover of river valley fragments by using GIS tools and multivariate analysis

    Science.gov (United States)

    Waldon-Rudzionek, Barbara

    2017-11-01

    Selected landscape registers and results of ecological analyses of flora used in studies of transformations of anthropogenic plant cover and river valley landscapes were presented. The results were shown pursuant to a comparison of fragments of two adjacent valleys in north-western Poland.

  11. ETIOLOGY OF YELLOW FEVER

    Science.gov (United States)

    Noguchi, Hideyo

    1922-01-01

    Analysis of the records of instances in which non-immune persons contracted yellow fever notwithstanding vaccination shows that the onset of disease occurs soon after vaccination, the longest period being 13 days. Since the average incubation period in yellow fever is 6 days, it seems that infection must have taken place in some instances during the period while protection was developing. These instances led to a study of the possibility of immediate protection by means of the anti-icteroides serum. It had already been shown that the immune serum protects at once against experimental Leptospira icteroides infection, but it remained to determine how long the protection would last. Guinea pigs were given different quantities of the immune serum and subsequently injected, at various intervals, with a virulent strain of Leptospira icteroides. Complete protection enduring 5 days was obtained with as minute a quantity of serum as 0.002 cc. per 1,000 gm. of body weight. After 5 days, however, the immune substance rapidly diminished, and to keep the animal protected for as long as 10 days it was necessary to give 100 times as much, or 0.2 cc. For a man weighing 80 kilos, 0.16 cc. (0.002 x 80) would theoretically be sufficient to protect for at least 5 days, 1.6 cc. for 7 days, and 16 cc. for 10 days. This temporary protection may be a valuable antecedent to that furnished by vaccination, since the final effect of the latter cannot be expected until at least 9 to 10 days have passed. PMID:19868677

  12. Rhombencephalitis associated with Dengue fever.

    Science.gov (United States)

    Verma, Rajesh; Bharti, Kavita; Mehta, Mannan; Bansod, Amrit

    2016-05-01

    Dengue infection is gradually disseminating throughout the world in alarming proportions. It is a arbovirus infection,transmitted by aedes mosquitoes. It is a multi-systemic disorder associated with varied neurological complications. There is increased trend of development of neurological complications in dengue fever. The neurological complications arising due to dengue infection can be categorized into central and neuromuscular complications. The central nervous system disorders reported with dengue fever are encephalopathy,encephalitis and myelitis.Here we report a case of rhombencephalitis associated with dengue fever. The literature does not mention rhombencephalitis occurring with dengue illness. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Laboratory Diagnosis of Lassa Fever.

    Science.gov (United States)

    Raabe, Vanessa; Koehler, Jeffrey

    2017-06-01

    Lassa virus remains an important cause of illness in West Africa and among the travelers returning from this region with an acute febrile illness. The symptoms of Lassa fever can be nonspecific and mimic those of other endemic infections, especially early in illness, making a clinical diagnosis difficult; therefore, laboratory testing is needed to confirm the diagnosis. An early identification of Lassa fever is crucial for maximizing the benefit of available antiviral therapy, as treatment efficacy rapidly decreases following the clinical onset of the disease. This minireview provides an overview of the currently available diagnostic tests for Lassa fever and their strengths and weaknesses. Copyright © 2017 American Society for Microbiology.

  14. Geometry of Valley Growth

    CERN Document Server

    Petroff, Alexander P; Abrams, Daniel M; Lobkovsky, Alexander E; Kudrolli, Arshad; Rothman, Daniel H

    2011-01-01

    Although amphitheater-shaped valley heads can be cut by groundwater flows emerging from springs, recent geological evidence suggests that other processes may also produce similar features, thus confounding the interpretations of such valley heads on Earth and Mars. To better understand the origin of this topographic form we combine field observations, laboratory experiments, analysis of a high-resolution topographic map, and mathematical theory to quantitatively characterize a class of physical phenomena that produce amphitheater-shaped heads. The resulting geometric growth equation accurately predicts the shape of decimeter-wide channels in laboratory experiments, 100-meter wide valleys in Florida and Idaho, and kilometer wide valleys on Mars. We find that whenever the processes shaping a landscape favor the growth of sharply protruding features, channels develop amphitheater-shaped heads with an aspect ratio of pi.

  15. Intermontane valley fills

    OpenAIRE

    Mey, Jürgen (Diplom-Geologe)

    2017-01-01

    Sedimentary valley fills are a widespread characteristic of mountain belts around the world. They transiently store material over time spans ranging from thousands to millions of years and therefore play an important role in modulating the sediment flux from the orogen to the foreland and to oceanic depocenters. In most cases, their formation can be attributed to specific fluvial conditions, which are closely related to climatic and tectonic processes. Hence, valley-fill deposits constitute v...

  16. Birds of Rishi Valley, and Renewal of their Habitats

    Indian Academy of Sciences (India)

    Nehru Memorial Museum Library. New Delhi, 1993, pp. 235. At a time when environmental concerns are commonly identified with lost causes and battles fought against heavy odds, it is a delight to come across a story of hope. Rishi. Valley's is a tale of ecological renewal in more ways than one. Rayalaseema, in Andhra.

  17. Range management research, Fort Valley Experimental Forest (P-53)

    Science.gov (United States)

    Henry A. Pearson; Warren P. Clary; Margaret M. Moore; Carolyn Hull Sieg

    2008-01-01

    Range management research at the Fort Valley Experimental Forest during the past 100 years has provided scientific knowledge for managing ponderosa pine forests and forest-range grazing lands in the Southwest. Three research timeperiods are identified: 1908 to 1950, 1950 to 1978, and 1978 to 2008. Early research (1908-1950) addressed ecological effects of livestock...

  18. Fever in Infants and Children

    Science.gov (United States)

    ... quickly lead to dehydration. Give your child an oral rehydration solution to prevent it. For the fever, give ... doctor or take your child to the emergency room right away.Start OverDiagnosisThese may be symptoms of ...

  19. Discriminating fever behavior in house flies.

    Directory of Open Access Journals (Sweden)

    Robert D Anderson

    Full Text Available Fever has generally been shown to benefit infected hosts. However, fever temperatures also carry costs. While endotherms are able to limit fever costs physiologically, the means by which behavioral thermoregulators constrain these costs are less understood. Here we investigated the behavioral fever response of house flies (Musca domestica L. challenged with different doses of the fungal entomopathogen, Beauveria bassiana. Infected flies invoked a behavioral fever selecting the hottest temperature early in the day and then moving to cooler temperatures as the day progressed. In addition, flies infected with a higher dose of fungus exhibited more intense fever responses. These variable patterns of fever are consistent with the observation that higher fever temperatures had greater impact on fungal growth. The results demonstrate the capacity of insects to modulate the degree and duration of the fever response depending on the severity of the pathogen challenge and in so doing, balance the costs and benefits of fever.

  20. Experimental therapies for yellow fever

    OpenAIRE

    Julander, Justin G.

    2012-01-01

    A number of viruses in the family Flaviviridae are the focus of efforts to develop effective antiviral therapies. Success has been achieved with inhibitors for the treatment of hepatitis C, and there is interest in clinical trials of drugs against dengue fever. Antiviral therapies have also been evaluated in patients with Japanese encephalitis and West Nile encephalitis. However, no treatment has been developed against the prototype flavivirus, yellow fever virus (YFV). Despite the availabili...

  1. Crimean-Congo hemorrhagic fever

    OpenAIRE

    Ergonul, O.

    2016-01-01

    Crimean Congo hemorrhagic fever virus (CCHFV) is a geographically widespread pathogen that causes severe hemorrhagic fever with high mortality. Although it is primarily zoonosis, sporadic cases and outbreaks of CCHF affecting humans do occur. The disease is endemic in many countries in Africa, Europe and Asia, and during 2002-2006, is has been reported in Turkey. People become infected through tick bites (especially Hyalomma spp.), by crushing infected ticks, after contact with a patient with...

  2. Treatment of dengue fever

    Directory of Open Access Journals (Sweden)

    Rajapakse S

    2012-07-01

    Full Text Available Senaka Rajapakse,1,2 Chaturaka Rodrigo,1 Anoja Rajapakse31Department of Clinical Medicine, Faculty of Medicine, University of Colombo, Sri Lanka; 2Lincoln County Hospital, United Lincolnshire NHS Trust, Lincoln, UK; 3Kings Mill Hospital, Sherwood Forest NHS Foundation Trust, Mansfield, UKAbstract: The endemic area for dengue fever extends over 60 countries, and approximately 2.5 billion people are at risk of infection. The incidence of dengue has multiplied many times over the last five decades at an alarming rate. In the endemic areas, waves of infection occur in epidemics, with thousands of individuals affected, creating a huge burden on the limited resources of a country's health care system. While the illness passes off as a simple febrile episode in many, a few have a severe illness marked by hypovolemic shock and bleeding. Iatrogenic fluid overload in the management may further complicate the picture. In this severe form dengue can be fatal. Tackling the burden of dengue is impeded by several issues, including a lack of understanding about the exact pathophysiology of the infection, inability to successfully control the vector population, lack of specific therapy against the virus, and the technical difficulties in developing a vaccine. This review provides an overview on the epidemiology, natural history, management strategies, and future directions for research on dengue, including the potential for development of a vaccine.Keywords: dengue, treatment, fluid resuscitation

  3. Ecological Schoolyards.

    Science.gov (United States)

    Danks, Sharon Gamson

    2000-01-01

    Presents design guidelines and organizational and site principles for creating schoolyards where students can learn about ecology. Principles for building schoolyard ecological systems are described. (GR)

  4. [Ebola and Marburg fever--outbreaks of viral haemorrhagic fever].

    Science.gov (United States)

    Chlíbek, R; Smetana, J; Vacková, M

    2006-12-01

    With an increasing frequency of traveling and tourism to exotic countries, a new threat-import of rare, very dangerous infections-emerges in humane medicine. Ebola fever and Marburg fever, whose agents come from the same group of Filoviridae family, belong among these diseases. The natural reservoir of these viruses has not yet been precisely determined. The pathogenesis of the diseases is not absolutely clear, there is neither a possibility of vaccination, nor an effective treatment. Fever and haemorrhagic diathesis belong to the basic symptoms of the diseases. Most of the infected persons die, the death rate is 70-88 %. The history of Ebola fever is relatively short-30 years, Marburg fever is known almost 40 years. Hundreds of people have died of these diseases so far. The study involves epidemics recorded in the world and their epidemiological relations. Not a single case has been recorded in the Czech Republic, nevertheless a sick traveler or infected animals are the highest risk of import these diseases. In our conditions, the medical staff belong to a highly endangered group of people because of stringent isolation of patients, strict rules of barrier treatment regime and high infectivity of the diseases. For this reason, the public should be prepared for possible contact with these highly virulent infections.

  5. A sero-epidemiological study of arboviral fevers in Djibouti, Horn of Africa.

    Directory of Open Access Journals (Sweden)

    Fred Andayi

    2014-12-01

    Full Text Available Arboviral infections have repeatedly been reported in the republic of Djibouti, consistent with the fact that essential vectors for arboviral diseases are endemic in the region. However, there is a limited recent information regarding arbovirus circulation, and the associated risk predictors to human exposure are largely unknown. We performed, from November 2010 to February 2011 in the Djibouti city general population, a cross-sectional ELISA and sero-neutralisation-based sero-epidemiological analysis nested in a household cohort, which investigated the arboviral infection prevalence and risk factors, stratified by their vectors of transmission. Antibodies to dengue virus (21.8% were the most frequent. Determinants of infection identified by multivariate analysis pointed to sociological and environmental exposure to the bite of Aedes mosquitoes. The population was broadly naïve against Chikungunya (2.6% with risk factors mostly shared with dengue. The detection of limited virus circulation was followed by a significant Chikungunya outbreak a few months after our study. Antibodies to West Nile virus were infrequent (0.6%, but the distribution of cases faithfully followed previous mapping of infected Culex mosquitoes. The seroprevalence of Rift valley fever virus was 2.2%, and non-arboviral transmission was suggested. Finally, the study indicated the circulation of Toscana-related viruses (3.7%, and a limited number of cases suggested infection by tick-borne encephalitis or Alkhumra related viruses, which deserve further investigations to identify the viruses and vectors implicated. Overall, most of the arboviral cases' predictors were statistically best described by the individuals' housing space and neighborhood environmental characteristics, which correlated with the ecological actors of their respective transmission vectors' survival in the local niche. This study has demonstrated autochthonous arboviral circulations in the republic of

  6. 17DD yellow fever vaccine

    Science.gov (United States)

    Martins, Reinaldo M.; Maia, Maria de Lourdes S.; Farias, Roberto Henrique G.; Camacho, Luiz Antonio B.; Freire, Marcos S.; Galler, Ricardo; Yamamura, Anna Maya Yoshida; Almeida, Luiz Fernando C.; Lima, Sheila Maria B.; Nogueira, Rita Maria R.; Sá, Gloria Regina S.; Hokama, Darcy A.; de Carvalho, Ricardo; Freire, Ricardo Aguiar V.; Filho, Edson Pereira; Leal, Maria da Luz Fernandes; Homma, Akira

    2013-01-01

    Objective: To verify if the Bio-Manguinhos 17DD yellow fever vaccine (17DD-YFV) used in lower doses is as immunogenic and safe as the current formulation. Results: Doses from 27,476 IU to 587 IU induced similar seroconversion rates and neutralizing antibodies geometric mean titers (GMTs). Immunity of those who seroconverted to YF was maintained for 10 mo. Reactogenicity was low for all groups. Methods: Young and healthy adult males (n = 900) were recruited and randomized into 6 groups, to receive de-escalating doses of 17DD-YFV, from 27,476 IU to 31 IU. Blood samples were collected before vaccination (for neutralization tests to yellow fever, serology for dengue and clinical chemistry), 3 to 7 d after vaccination (for viremia and clinical chemistry) and 30 d after vaccination (for new yellow fever serology and clinical chemistry). Adverse events diaries were filled out by volunteers during 10 d after vaccination. Volunteers were retested for yellow fever and dengue antibodies 10 mo later. Seropositivity for dengue was found in 87.6% of volunteers before vaccination, but this had no significant influence on conclusions. Conclusion: In young healthy adults Bio-Manguinhos/Fiocruz yellow fever vaccine can be used in much lower doses than usual. International Register ISRCTN 38082350. PMID:23364472

  7. Geographic patterns and environmental factors associated with human yellow fever presence in the Americas.

    Science.gov (United States)

    Hamrick, Patricia Najera; Aldighieri, Sylvain; Machado, Gustavo; Leonel, Deise Galan; Vilca, Luz Maria; Uriona, Sonia; Schneider, Maria Cristina

    2017-09-01

    In the Americas, yellow fever virus transmission is a latent threat due to the proximity between urban and wild environments. Although yellow fever has nearly vanished from North and Central America, there are still 13 countries in the Americas considered endemic by the World Health Organization. Human cases usually occur as a result of the exposure to sylvatic yellow fever in tropical forested environments; but urban outbreaks reported during the last decade demonstrate that the risk in this environment still exists. The objective of this study was to identify spatial patterns and the relationship between key geographic and environmental factors with the distribution of yellow fever human cases in the Americas. An ecological study was carried out to analyze yellow fever human cases reported to the Pan American Health Organization from 2000 to 2014, aggregated by second administrative level subdivisions (counties). Presence of yellow fever by county was used as the outcome variable and eight geo-environmental factors were used as independent variables. Spatial analysis was performed to identify and examine natural settings per county. Subsequently, a multivariable logistic regression model was built. During the study period, 1,164 cases were reported in eight out of the 13 endemic countries. Nearly 83.8% of these cases were concentrated in three countries: Peru (37.4%), Brazil (28.1%) and Colombia (18.4%); and distributed in 57 states/provinces, specifically in 286 counties (3.4% of total counties). Yellow fever presence was significantly associated with altitude, rain, diversity of non-human primate hosts and temperature. A positive spatial autocorrelation revealed a clustered geographic pattern in 138/286 yellow fever positive counties (48.3%). A clustered geographic pattern of yellow fever was identified mostly along the Andes eastern foothills. This risk map could support health policies in endemic countries. Geo-environmental factors associated with presence

  8. Managing Rocky Mountain spotted fever.

    Science.gov (United States)

    Minniear, Timothy D; Buckingham, Steven C

    2009-11-01

    Rocky Mountain spotted fever is caused by the tick-borne bacterium Rickettsia rickettsii. Symptoms range from moderate illness to severe illness, including cardiovascular compromise, coma and death. The disease is prevalent in most of the USA, especially during warmer months. The trademark presentation is fever and rash with a history of tick bite, although tick exposure is unappreciated in over a third of cases. Other signature symptoms include headache and abdominal pain. The antibiotic therapy of choice for R. rickettsii infection is doxycycline. Preventive measures for Rocky Mountain spotted fever and other tick-borne diseases include: wearing long-sleeved, light colored clothing; checking for tick attachment and removing attached ticks promptly; applying topical insect repellent; and treating clothing with permethrin.

  9. Boyne Valley Tombs

    Science.gov (United States)

    Prendergast, Frank

    The passage tombs of the Boyne Valley exhibit the greatest level of development of the megalithic tomb building tradition in Ireland in terms of their morphology, embellishment, burial tradition, grave goods, clustering, and landscape siting. This section examines these characteristics and gives a summary archaeoastronomical appraisal of their orientation and detected astronomical alignment.

  10. Fever of unknown origin: subacute thyroiditis versus typhoid fever.

    Science.gov (United States)

    Cunha, Burke A; Thermidor, Marjorie; Mohan, Sowjanya; Valsamis, Ageliki S; Johnson, Diane H

    2005-01-01

    Fever of unknown origin (FUO) is not infrequently a diagnostic dilemma for clinicians. Common infectious causes include endocarditis and abscesses in adults, and noninfectious causes include neoplasms and certain collagen vascular diseases, for example, polymyalgia rheumatica, various vasculitides, and juvenile rheumatoid arthritis (adult Still's disease). Subacute thyroiditis is a rare cause of FUO. Among the infectious causes of FUO, typhoid fever is relatively uncommon. We present a case of FUO in a traveler returning from India whose initial complaints were that of left-sided neck pain and angle of the jaw pain, which initially suggested the diagnosis of subacute thyroiditis. After an extensive FUO workup, when typhoid fever is a likely diagnostic possibility, an empiric trial of anti- Salmonella therapy has diagnostic and therapeutic significance. The presence of relative bradycardia, and response to quinolone therapy, was the basis of the clinical diagnosis of typhoid fever as the explanation for this patients FUO. This case illustrates the diagnostic difficulties in assessing patients with FUO with few diagnostic findings.

  11. relapsing fever, a disappearing cause of fever and maternal death

    African Journals Online (AJOL)

    2013-04-01

    Apr 1, 2013 ... labor, puerperal sepsis, post-partum haemorrhage, complications of abortion, and pre-eclampsia. There were few reports of abortions and abortion-related mortality. Relapsing fever or Borrelia infection was an indirect cause of death common to the region and particularly hazardous to pregnant women and ...

  12. Overview of Classical Swine Fever (Hog Cholera, Classical Swine fever)

    Science.gov (United States)

    Classical swine fever is a contagious often fatal disease of pigs clinically characterized by high body temperature, lethargy, yellowish diarrhea, vomits and purple skin discoloration of ears, lower abdomen and legs. It was first described in the early 19th century in the USA. Later, a condition i...

  13. Bringing Silicon Valley inside.

    Science.gov (United States)

    Hamel, G

    1999-01-01

    In 1998, Silicon Valley companies produced 41 IPOs, which by January 1999 had a combined market capitalization of $27 billion--that works out to $54,000 in new wealth creation per worker in a single year. Multiply the number of employees in your company by $54,000. Did your business create that much new wealth last year? Half that amount? It's not a group of geniuses generating such riches. It's a business model. In Silicon Valley, ideas, capital, and talent circulate freely, gathering into whatever combinations are most likely to generate innovation and wealth. Unlike most traditional companies, which spend their energy in resource allocation--a system designed to avoid failure--the Valley operates through resource attraction--a system that nurtures innovation. In a traditional company, people with innovative ideas must go hat in hand to the guardians of the old ideas for funding and for staff. But in Silicon Valley, a slew of venture capitalists vie to attract the best new ideas, infusing relatively small amounts of capital into a portfolio of ventures. And talent is free to go to the companies offering the most exhilarating work and the greatest potential rewards. It should actually be easier for large, traditional companies to set up similar markets for capital, ideas, and talent internally. After all, big companies often already have extensive capital, marketing, and distribution resources, and a first crack at the talent in their own ranks. And some of them are doing it. The choice is yours--you can do your best to make sure you never put a dollar of capital at risk, or you can tap into the kind of wealth that's being created every day in Silicon Valley.

  14. What about My Child and Rheumatic Fever?

    Science.gov (United States)

    ... occur after a streptococcal infection of the throat (“strep throat”). Most strep throat infections don’t lead to rheumatic fever. When they do, the time between the strep throat and rheumatic fever is about two to four ...

  15. Estudo preliminar sobre a ecologia de Lontra longicaudis (Olfers (Carnivora, Mustelidae no Vale do Taquari, Sul do Brasil Preliminary study by the ecology of Lontra longicaudis (Olfers (Carnivora, Mustelidae in Taquari Valley, South Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Benhur Kasper

    2004-03-01

    Full Text Available O estudo foi realizado em duas áreas no Vale do Taquari, região central do Estado do Rio Grande do Sul, Sul do Brasil. Entre agosto de 2000 e dezembro de 2001 foi realizado um estudo sobre a dieta e o uso de abrigos e marcas odoríferas por Lontra longicaudis (Olfers, 1818. Coletaram-se 275 marcas odoríferas, das quais 261 foram analisadas para determinação da dieta. O uso de marcas odoríferas ocorreu por deposição de fezes, sobretudo sobre locais conspícuos das margens dos rios ou no interior dos abrigos. Os abrigos foram formados principalmente por escavação paralela a margem dos rios. Estes abrigos foram altamente reutilizados. Ocorreu predação sobre três grupos de presas: peixes, mamíferos e insetos. Os peixes formam a base da dieta, e as famílias Loricariidae/Callichthyidae, Cichlidae, Pimelodidae/Auchenipteridae e Erythrinidae foram as mais freqüentes nas análises fecais. A ocorrência destes grupos de peixes na dieta é maior do que sua disponibilidade relativa no ambiente.The study was carried out in two areas of Taquari Valley, central region of Rio Grande do Sul State, Southern Brazil. Between August 2000 and December 2001 a study about diet and use of shelters and scent marks by Lontra longicaudis (Olfers, 1818 was performed. 275 spraints were colleted, of which 261 were analised for diet determination. The use of scent marks occured by the deposition of feaces mainly under conspicuous sites of the river margin or inside the shelters. The shelters were often formed by parallel excavation of river margin. The shelters were highly reused. Predation occurred on 3 groups of preys: Fish, Mammals and Insects. The fish, formed the diet base, and the families Loricariidae/Callichthyidae, Cichlidae, Pimelodidae/ Auchenipteridae and Erythrinidae were the most frequently identified ones in fecal analysis. The occurrence of these fish groups in the diet was higher then the relative availability in environment.

  16. Typhoid fever: the experience of last decade

    OpenAIRE

    A. N. Kovalenko; A. M. Ivanov; N. S. Odynaev; M. I. Rachmanov; A. A. Murachev

    2009-01-01

    This article is about analyses of diagnostics and treatment of the modern typhoid fever. In the past typhoid fever was critical and lifethreatening inflectional disease. But nowadays thanks to using of chloramphenicol and other antimicrobial preparations, typhoid fever is serious but well curable disease. In the second part of the 20th century the number of typhoid fever cases has decreased. As a result a new generation of physicians, who has never come across this disease, appeared. Nowadays...

  17. Abdominal Disturbances Among Dengue Fever Patients

    OpenAIRE

    Harahap, Arnold Hasahatan; Simadibrata, Marcellus; Makmun, Dadang; Hasan, Irsan

    2009-01-01

    Background: Abdominal disturbances are common symptoms found in approximately 40% of patients with dengue fever, which frequently cause significant morbidity. This study was developed as an attempt to understand the effect of plasma leakage in dengue hemorrhagic fever; particularly on ab dominal problems. Method: The study was conducted in hospitalized patients who were diagnosed with dengue fever and dengue hemorrhagic fever (based on the 1997 WHO criteria for DHF) at Fatmawati hospital, Ja...

  18. Mothers' Perception of Fever Management in Children

    African Journals Online (AJOL)

    Alasia Datonye

    Results: A total of 151 mothers participated with age range 19 years to 54 years with mean of 31.4±5.7SD. One hundred and thirteen (74.8%) defined fever as hotness of the body. Commonest associated symptom with fever was loss of appetite (71.5%). Commonest identified cause of fever was malaria (71 (47%) mothers).

  19. Yellow Fever Outbreak, Southern Sudan, 2003

    Science.gov (United States)

    Onyango, Clayton O.; Grobbelaar, Antoinette A.; Gibson, Georgina V.F.; Sang, Rosemary C.; Sow, Abdourahmane; Swanepoel, Robert

    2004-01-01

    In May 2003, an outbreak of fatal hemorrhagic fever, caused by yellow fever virus, occurred in southern Sudan. Phylogenetic analysis showed that the virus belonged to the East African genotype, which supports the contention that yellow fever is endemic in East Africa with the potential to cause large outbreaks in humans. PMID:15498174

  20. First Outbreak of Dengue Hemorrhagic Fever, Bangladesh

    OpenAIRE

    Rahman, Mahbubur; Rahman, Khalilur; Siddque, A. K.; Shoma, Shereen; Kamal, A.H.M.; Ali, K.S.; Nisaluk, Ananda; Robert F Breiman

    2002-01-01

    During the first countrywide outbreak of dengue hemorrhagic fever in Bangladesh, we conducted surveillance for dengue at a hospital in Dhaka. Of 176 patients, primarily adults, found positive for dengue, 60.2% had dengue fever, 39.2% dengue hemorrhagic fever, and 0.6% dengue shock syndrome. The Dengue virus 3 serotype was detected in eight patients.

  1. Fever, sore throat and myalgia

    African Journals Online (AJOL)

    a continual significant fever daily. Shotty cervical lymphadenopathy was noted. The relevant laboratory investigations are shown in Table 1. On admission to tertiary care, an aetiological differential diagnosis for the pyrexia of unknown origin (PUO)[1] (Table 2) included retropharyngeal abscess, Lemierre's syndrome, HIV ...

  2. Sandfly Fever Sicilian Virus, Algeria

    Science.gov (United States)

    Izri, Arezki; Temmam, Sarah; Moureau, Grégory; Hamrioui, Boussad; de Lamballerie, Xavier

    2008-01-01

    To determine whether sandfly fever Sicilian virus (SFSV) is present in Algeria, we tested sandflies for phlebovirus RNA. A sequence closely related to that of SFSV was detected in a Phlebotomus ariasi sandfly. Of 60 human serum samples, 3 contained immunoglobulin G against SFSV. These data suggest SFSV is present in Algeria. PMID:18439364

  3. Diarrhea associated with typhoid fever

    NARCIS (Netherlands)

    Roy, S. K.; Speelman, P.; Butler, T.; Nath, S.; Rahman, H.; Stoll, B. J.

    1985-01-01

    To study the pathogenesis of diarrhea occurring with typhoid fever, we selected 42 patients with diarrhea and blood cultures positive for Salmonella typhi or Salmonella paratyphi A, but without diarrheal copathogens, for measurement of stool output and examination of fecal composition. The mean

  4. Behavioral fever in newborn rabbits

    Science.gov (United States)

    Satinoff, E.; Mcewen, G. N., Jr.; Williams, B. A.

    1976-01-01

    New Zealand white rabbit pups aged 12 to 72 hr were divided into three groups and given an intraperitoneal injection of Pseudomonas polysaccharide, a saline vehicle alone, and no treatment, respectively. The animals injected with pyrogen and maintained at an ambient temperature of 32 C for 2 hr did not develop fever. When placed in a thermally graded alleyway, the animals injected with pyrogen selected gradient positions that represented significantly higher temperatures than controls injected with saline. Further stay at selected positions for 5 min caused a considerable increase in the rectal temperature of the pyrogen-injected pups but not that of controls. The results support the hypothesis that newborn rabbits will develop a fever by behavioral means after a single injection of an exogenous pyrogen if the opportunity for thermoregulatory behavior is present. No fever develops if the pups must rely solely on internal thermoregulatory mechanisms. The behavioral system for producing a fever is mature at birth, but an adequate system of internal reflexes does not appear to develop for some days.

  5. THE TRANSMISSION OF YELLOW FEVER

    Science.gov (United States)

    Davis, Nelson C.

    1930-01-01

    1. Saimiri sciureus has been infected with yellow fever virus, both by the inoculation of infectious blood and by the bites of infective mosquitoes. Some of the monkeys have died, showing lesions, including hepatic necrosis, suggesting yellow fever as seen in human beings and in rhesus monkeys. Virus has been transferred back to M. rhesus from infected Saimiri both by blood inoculation and by mosquito bites. The virus undoubtedly has been maintained through four direct passages in Saimiri. Reinoculations of infectious material into recovered monkeys have not given rise to invasion of the blood stream by virus. Sera from recovered animals have protected M. rhesus against the inoculation of virus. 2. It has been possible to pass the virus to and from Ateleus ater by the injection of blood or liver and by the bites of mosquitoes. The livers from two infected animals have shown no necrosis. The serum from one recovered monkey proved to be protective for M. rhesus. 3. Only three out of twelve Lagothrix lagotricha have reacted to yellow fever virus by a rise in temperature. Probably none have died as a result of the infection. In only one instance has the virus been transferred back to M. rhesus. The sera of recovered animals have had a protective action against yellow fever virus. PMID:19869721

  6. Green valley galaxies

    Directory of Open Access Journals (Sweden)

    Salim S.

    2014-01-01

    Full Text Available The “green valley” is a wide region separating the blue and the red peaks in the ultraviolet-optical color magnitude diagram, first revealed using GALEX UV photometry. The term was coined by Christopher Martin (Caltech, in 2005. Green valley highlights the discriminating power of UV to very low relative levels of ongoing star formation, to which the optical colors, including u−r, are insensitive. It corresponds to massive galaxies below the star-forming, “main” sequence, and therefore represents a critical tool for the study of the quenching of star formation and its possible resurgence in otherwise quiescent galaxies. This article reviews the results pertaining to (predominantly disk morphology, structure, environment, dust content and gas properties of green valley galaxies in the local universe. Their relationship to AGN is also discussed. Attention is given to biases emerging from defining the “green valley” using optical colors. We review various evolutionary scenarios and we present evidence for a new one, the quasi-static view of the green valley, in which the majority (but not all of galaxies currently in the green valley were only partially quenched in the distant past and now participate in a slow cosmic decline of star formation, which also drives down the activity on the main sequence, presumably as a result of the dwindling accretion/cooling onto galaxy disks. This emerging synthetic picture is based on the findings from Fang et al. (2012, Salim et al. (2012 and Martin et al. (2007, as well as other results.

  7. Fluvial valleys and Martian palaeoclimates

    Science.gov (United States)

    Gulick, Virginia C.; Baker, Victor R.

    1989-10-01

    Theoretical models of early Martian atmospheric evolution describe the maintenance of a dense CO2 atmosphere and a warm, wet climate until the end of the heavy-bombardment phase of impacting. However, the presence of very young, earthlike fluvial valleys on the northern flank of Alba Patera conflicts with this scenario. Whereas the widespread ancient Martian valleys generally have morphologies indicative of sapping erosion by the slow outflow of subsurface water, the local Alba valleys were probably formed by surface-runoff processes. Because subsurface water flow might be maintained by hydrothermal energy inputs and because surface-runoff valleys developed late in Martian history, it is not necessary to invoke drastically different planet-wide climatic conditions to explain valley development on Mars. The Alba fluvial valleys can be explained by hydrothermal activity or outflow-channel discharges that locally modified the atmosphere, including precipitation and local overland flow on low-permeability volcanic ash.

  8. Rheumatic fever prophylaxis: Gisborne experience.

    Science.gov (United States)

    Frankish, J D

    1984-10-10

    There were 300 admissions to the Cook Hospital with rheumatic fever in 1958-83. During 1958-73 oral penicillin was used for secondary prophylaxis and 77 (35%) of 223 admissions were recurrences. From 1974-83 when parenteral benzathine penicillin was increasingly used there were 77 admissions of which 14 (18%) were readmissions. An effective programme of secondary prophylaxis using benzathine penicillin and co-ordination of hospital and community health services is outlined. One hundred and eight patients with a first attack of rheumatic fever were seen in 1968-82. The chance of a recurrence in patients in whom oral prophylaxis was instituted was 15% two years after the initial attack and 35% after six years. Institution of parenteral prophylaxis significantly reduced the risk of recurrence (p = 0.0009) which was 2% six years after the first attack.

  9. Yellow Fever: A Reemerging Threat

    Science.gov (United States)

    Gardner, Christina L.; Ryman, Kate D.

    2014-01-01

    Yellow fever (YF) is a viral disease, endemic to tropical regions of Africa and the Americas. YF principally affects humans and nonhuman primates, and is transmitted via the bite of infected mosquitoes. The agent of YF, yellow fever virus (YFV), can cause devastating epidemics of potentially fatal, hemorrhagic disease. We rely on mass vaccination campaigns to prevent and control these outbreaks. However, the risk of major YF epidemics, especially in densely populated, poor urban settings, both in Africa and South America, has greatly increased due to: (1) reinvasion of urban settings by the mosquito vector of YF, Aedes aegypti; (2) rapid urbanization, particularly in parts of Africa, with populations shifting from rural to predominantly urban; and (3) waning immunization coverage. Consequently, YF is considered an emerging, or reemerging disease of considerable importance. PMID:20513550

  10. Imported chikungunya fever in Madrid.

    Science.gov (United States)

    Richi Alberti, Patricia; Steiner, Martina; Illera Martín, Óscar; Alcocer Amores, Patricia; Cobo Ibáñez, Tatiana; Muñoz Fernández, Santiago

    2016-01-01

    Chikungunya Fever is a mosquito-transmitted viral disease that causes fever, rash and musculoskeletal complaints. The latest may persist for several months, or even years or developed a relapsing course, that deserve an adequate treatment. Due to the large outbreak declared in the Caribbean in 2013, imported cases of Chikungunya as well as the risk of autochthonous transmission in case of available vectors have increased in non-endemic countries, like Spain. We described four cases of Chikungunya treated in our clinic. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  11. Optical manipulation of valley pseudospin

    Science.gov (United States)

    Ye, Ziliang; Sun, Dezheng; Heinz, Tony F.

    2017-01-01

    The coherent manipulation of spin and pseudospin underlies existing and emerging quantum technologies, including quantum communication and quantum computation. Valley polarization, associated with the occupancy of degenerate, but quantum mechanically distinct valleys in momentum space, closely resembles spin polarization and has been proposed as a pseudospin carrier for the future quantum electronics. Valley exciton polarization has been created in the transition metal dichalcogenide monolayers using excitation by circularly polarized light and has been detected both optically and electrically. In addition, the existence of coherence in the valley pseudospin has been identified experimentally. The manipulation of such valley coherence has, however, remained out of reach. Here we demonstrate all-optical control of the valley coherence by means of the pseudomagnetic field associated with the optical Stark effect. Using below-bandgap circularly polarized light, we rotate the valley exciton pseudospin in monolayer WSe2 on the femtosecond timescale. Both the direction and speed of the rotation can be manipulated optically by tuning the dynamic phase of excitons in opposite valleys. This study unveils the possibility of generation, manipulation, and detection of the valley pseudospin by coupling to photons.

  12. Dengue fever complicated by hemophagocytosis

    OpenAIRE

    Koshy, Maria; Mishra, Ajay Kumar; Agrawal, Bhumi; Kurup, Akhil Rajendra; Hansdak, Samuel George

    2016-01-01

    Dengue is a common acute viral febrile illness in the tropics. Although the usual presentation is that of a self-limiting illness, its complications are protean. We report a 29-year-old man who presented with an acute febrile illness and was diagnosed with dengue hemorrhagic fever. Despite appropriate supportive therapy, the patient initially improved, but subsequently had clinical deterioration. Evaluation revealed features of hemophagocytic lymphohistiocytosis. He was successfully treated w...

  13. [Crimean-Congo hemorrhagic fever].

    Science.gov (United States)

    Saijo, Masayuki; Moriikawa, Shigeru; Kurane, Ichiro

    2004-12-01

    Crimean-Congo hemorrhagic fever (CCHF) is an acute infectious disease caused by CCHF virus (CCHFV), a member of the family Bunyaviridae, genus Nairovirus. The case fatality rate of CCHF ranges from 10-40%. Because CCHF is not present in Japan, many Japanese virologists and clinicians are not very familiar with this disease. However, there remains the possibility of an introduction of CCHFV or other hemorrhagic fever viruses into Japan from surrounding endemic areas. Development of diagnostic laboratory capacity for viral hemorrhagic fevers is necessary even in countries without these diseases. At the National Institute of Infectious Diseases, Tokyo, Japan, laboratory-based systems such as recombinant protein-based antibody detection, antigen-capture and pathological examination have been developed. In this review article, epidemiologic and clinical data on CCHF in the Xinjiang Uygur Autonomous Region, compiled through field investigations and diagnostic testing utilizing the aforementioned laboratory systems, are presented. CCHFV infections are closely associated with the environmental conditions, life styles, religion, occupation, and human economic activities. Based on these data, preventive measures for CCHFV infections are also discussed.

  14. Azathioprine-induced fever in autoimmune hepatitis

    Science.gov (United States)

    Khoury, Tawfik; Ollech, Jacob E; Chen, Shmuel; Mizrahi, Meir; Shalit, Meir

    2013-01-01

    Underdiagnosis of drug-induced fever leads to extensive investigation and prolongation of hospitalization, and may lead to multiple unnecessary invasive procedures and a wrong diagnosis. Azathioprine is a widely used immunosuppressive drug. We report a case of a 53-year-old female patient diagnosed with autoimmune hepatitis treated with azathioprine, who presented to the emergency room with a 6-wk history of fever and chills without other associated symptoms. Since the patient’s fever was of unknown origin, she was hospitalized. All treatment was stopped and an extensive workup to explore the source of fever and chills was performed. Results of chest X-ray, viral, urine, and blood cultures, autoimmune serology, transthoracic and transesophageal echocardiography, and abdominal ultrasound revealed no source of infection. A rechallenge test of azathioprine was performed and the fever and chills returned within a few hours. Azathioprine was established as the definite cause following rechallenge. Fever as an adverse drug reaction is often unrecognized. Azathioprine has been reported to cause drug-induced fever in patients with inflammatory bowel disease, rheumatoid arthritis, and sarcoidosis. To the best of our knowledge there have been no previous reports documenting azathioprine-induced fever in patients with autoimmune hepatitis. The occurrence of fever following the readministration of azathioprine suggests the diagnosis of drug-induced fever, particularly after the exclusion of other causes. A careful rechallenge is recommended to confirm the diagnosis. PMID:23840156

  15. Landscape Ecology

    DEFF Research Database (Denmark)

    Christensen, Andreas Aagaard; Brandt, Jesper; Svenningsen, Stig Roar

    2017-01-01

    Landscape ecology is an interdisciplinary field of research and practice that deals with the mutual association between the spatial configuration and ecological functioning of landscapes, exploring and describing processes involved in the differentiation of spaces within landscapes......, and the ecological significance of the patterns which are generated by such processes. In landscape ecology, perspectives drawn from existing academic disciplines are integrated based on a common, spatially explicit mode of analysis developed from classical holistic geography, emphasizing spatial and landscape...... pattern analysis and ecological interaction of land units. The landscape is seen as a holon: an assemblage of interrelated phenomena, both cultural and biophysical, that together form a complex whole. Enduring challenges to landscape ecology include the need to develop a systematic approach able...

  16. Restoration Ecology

    Science.gov (United States)

    Jordan, William R.; Gilpin, Michael E.; Aber, John D.

    1990-08-01

    This book explores the ecological concepts and ideas involved in the practice of habitat restoration by taking a theoretical approach that will appeal to ecologists concerned with the structure and dynamics of communities. The contributors examine aspects of this new realization and its implications for both ecology and the practice of habitat restoration. What emerges is the outline of a new paradigm for ecological research and the basis for a stronger relationship between theory and practice in this area.

  17. Agricultural Development, Land Change, and Livelihoods in Tanzania's Kilombero Valley

    Science.gov (United States)

    Connors, John Patrick

    The Kilombero Valley lies at the intersection of a network of protected areas that cross Tanzania. The wetlands and woodlands of the Valley, as well as the forest of surrounding mountains are abundant in biodiversity and are considered to be critical areas for conservation. This area, however, is also the home to more than a half million people, primarily poor smallholder farmers. In an effort to support the livelihoods and food security of these farmers and the larger Tanzanian population, the country has recently targeted a series of programs to increase agricultural production in the Kilombero Valley and elsewhere in the country. Bridging concepts and methods from land change science, political ecology, and sustainable livelihoods, I present an integrated assessment of the linkages between development and conservation efforts in the Kilombero Valley and the implications for food security. This dissertation uses three empirical studies to understand the process of development in the Kilombero Valley and to link the priorities and perceptions of conservation and development efforts to the material outcomes in food security and land change. The first paper of this dissertation examines the changes in land use in the Kilombero Valley between 1997 and 2014 following the privatization of agriculture and the expansion of Tanzania's Kilimo Kwanza program. Remote sensing analysis reveals a two-fold increase in agricultural area during this short time, largely at the expense of forest. Protected areas in some parts of the Valley appear to be deterring deforestation, but rapid agricultural growth, particularly surrounding a commercial rice plantation, has led to loss of extant forest and sustained habitat fragmentation. The second paper focuses examines livelihood strategies in the Valley and claims regarding the role of agrobiodiversity in food security. The results of household survey reveal no difference or lower food security among households that diversify their

  18. Spatiotemporal causal modeling for the management of Dengue Fever

    Science.gov (United States)

    Yu, Hwa-Lung; Huang, Tailin; Lee, Chieh-Han

    2015-04-01

    Increasing climatic extremes have caused growing concerns about the health effects and disease outbreaks. The association between climate variation and the occurrence of epidemic diseases play an important role on a country's public health systems. Part of the impacts are direct casualties associated with the increasing frequency and intensity of typhoons, the proliferation of disease vectors and the short-term increase of clinic visits on gastro-intestinal discomforts, diarrhea, dermatosis, or psychological trauma. Other impacts come indirectly from the influence of disasters on the ecological and socio-economic systems, including the changes of air/water quality, living environment and employment condition. Previous risk assessment studies on dengue fever focus mostly on climatic and non-climatic factors and their association with vectors' reproducing pattern. The public-health implication may appear simple. Considering the seasonal changes and regional differences, however, the causality of the impacts is full of uncertainties. Without further investigation, the underlying dengue fever risk dynamics may not be assessed accurately. The objective of this study is to develop an epistemic framework for assessing dynamic dengue fever risk across space and time. The proposed framework integrates cross-departmental data, including public-health databases, precipitation data over time and various socio-economic data. We explore public-health issues induced by typhoon through literature review and spatiotemporal analytic techniques on public health databases. From those data, we identify relevant variables and possible causal relationships, and their spatiotemporal patterns derived from our proposed spatiotemporal techniques. Eventually, we create a spatiotemporal causal network and a framework for modeling dynamic dengue fever risk.

  19. Fever and signs of shock: the essential dangerous fever.

    Science.gov (United States)

    Reifel Saltzberg, Jennifer M

    2013-11-01

    A common cause of fever with signs of shock is sepsis. Sepsis describes the spectrum of illness caused by severe infection. The incidence of sepsis is increasing and mortality can be high. Diagnosing the disease and implementing treatment early can decrease mortality. Early treatment includes empirical antibiotics and resuscitation. The diverse physiology present in sepsis can make the resuscitation complex; many different types of hemodynamic monitoring may be necessary. Even with this complexity, an organized approach can improve patient outcomes. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. NNDSS - Table II. Salmonellosis (excluding typhoid fever and paratyphoid fever) to Shigellosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Salmonellosis (excluding typhoid fever and paratyphoid fever) to Shigellosis - 2018. In this Table, provisional cases of selected notifiable...

  1. Soil Ecology

    Science.gov (United States)

    Killham, Ken

    1994-04-01

    Soil Ecology is designed to meet the increasing challenge faced by today's environmental scientists, ecologists, agriculturalists, and biotechnologists for an integrated approach to soil ecology. It emphasizes the interrelations among plants, animals, and microbes, by first establishing the fundamental physical and chemical properties of the soil habitat and then functionally characterizing the major components of the soil biota and some of their most important interactions. The fundamental principles underpinning soil ecology are established and this then enables an integrated approach to explore and understand the processes of soil nutrient (carbon, nitrogen, and phosphorus) cycling and the ecology of extreme soil conditions such as soil-water stress. Two of the most topical aspects of applied soil ecology are then selected. First, the ecology of soil pollution is examined, focusing on acid deposition and radionuclide pollution. Second, manipulation of soil ecology through biotechnology is discussed, illustrating the use of pesticides and microbial inocula in soils and pointing toward the future by considering the impact of genetically modified inocula on soil ecology.

  2. Hepatic involvement in dengue Fever in children

    National Research Council Canada - National Science Library

    Jagadishkumar, Kalenahalli; Jain, Puja; Manjunath, Vaddambal G; Umesh, Lingappa

    2012-01-01

    .... 110 children with serologically positive dengue fever aged between 2 months - 14 years were studied for their hepatic functions both clinically and biochemically after excluding malaria, enteric...

  3. Describing the Breakbone Fever: IDODEN, an Ontology for Dengue Fever

    Science.gov (United States)

    Mitraka, Elvira; Topalis, Pantelis; Dritsou, Vicky; Dialynas, Emmanuel; Louis, Christos

    2015-01-01

    Background Ontologies represent powerful tools in information technology because they enhance interoperability and facilitate, among other things, the construction of optimized search engines. To address the need to expand the toolbox available for the control and prevention of vector-borne diseases we embarked on the construction of specific ontologies. We present here IDODEN, an ontology that describes dengue fever, one of the globally most important diseases that are transmitted by mosquitoes. Methodology/Principal Findings We constructed IDODEN using open source software, and modeled it on IDOMAL, the malaria ontology developed previously. IDODEN covers all aspects of dengue fever, such as disease biology, epidemiology and clinical features. Moreover, it covers all facets of dengue entomology. IDODEN, which is freely available, can now be used for the annotation of dengue-related data and, in addition to its use for modeling, it can be utilized for the construction of other dedicated IT tools such as decision support systems. Conclusions/Significance The availability of the dengue ontology will enable databases hosting dengue-associated data and decision-support systems for that disease to perform most efficiently and to link their own data to those stored in other independent repositories, in an architecture- and software-independent manner. PMID:25646954

  4. Fever-Induced Brugada Syndrome

    Directory of Open Access Journals (Sweden)

    Sandhya Manohar MD

    2015-03-01

    Full Text Available Brugada syndrome is increasingly recognized as a cause of sudden cardiac death. Many of these patients do not get diagnosed due its dynamic and often hidden nature. We have come a long way in understanding the disease process, and its electrophysiology appears to be intimately linked with sodium channel mutations or disorders. The cardiac rhythm in these patients can deteriorate into fatal ventricular arrhythmias. This makes it important for the clinician to be aware of the conditions in which arrhythmogenicity of Brugada syndrome is revealed or even potentiated. We present such an instance where our patient’s Brugada syndrome was unmasked by fever.

  5. Dengue fever complicated by hemophagocytosis

    Science.gov (United States)

    Koshy, Maria; Mishra, Ajay Kumar; Agrawal, Bhumi; Kurup, Akhil Rajendra; Hansdak, Samuel George

    2016-01-01

    Dengue is a common acute viral febrile illness in the tropics. Although the usual presentation is that of a self-limiting illness, its complications are protean. We report a 29-year-old man who presented with an acute febrile illness and was diagnosed with dengue hemorrhagic fever. Despite appropriate supportive therapy, the patient initially improved, but subsequently had clinical deterioration. Evaluation revealed features of hemophagocytic lymphohistiocytosis. He was successfully treated with glucocorticoids and had an uneventful recovery. This case adds to the limited adult cases of virus-associated hemophagocytic syndrome in the literature and the need for prompt recognition and treatment of this rare complication. PMID:27274854

  6. [Myocarditis in severe typhoid fever].

    Science.gov (United States)

    Bobin, A N; Antukh, E A; Parkhomenko, Iu G; Makanin, M A

    2005-01-01

    The article explains the development of toxic infective myocarditis and, in many cases, pancarditis, in patients with severe typhoid fever (TF) with lethal outcome. The authors present the most frequently found symptoms and ECG signs, the main histological features and possibilities of clinical diagnostics of myocarditis. The latter is of special importance, because a significant number of patients do not have typical clinical presentation. The work is based on the data from 109 autopsy records and 42 case histories as well as the results of morphological study of the heart in archive samples received from 47 military men who died of TF.

  7. Geographical distribution of the red howler monkey (Alouatta seniculus) and yellow fever in Colombia.

    Science.gov (United States)

    Piedrahita-Cortés, Juan; Soler-Tovar, Diego

    2016-02-11

    Colombia is a country with an important diversity of non-human primates, of which the red howler monkey (Alouatta seniculus) stands out because of its distribution and the role it plays in the occurrence of yellow fever.  To describe the geographic co-occurrence of Alouatta seniculus and the reported presence of yellow fever.  We conducted a descriptive study. The reported presence of yellow fever in Colombia was obtained from the reports and bulletins issued by the Instituto Nacional de Salud, and the study by Segura, et al. (2013). The occurrence of A. seniculus was determined based on the data from the Global Biodiversity Information Facility and the Colombian Biodiversity Information System. A map of the occurrence was developed using the DIVA-GIS program, and the ecological niche model under current conditions was created with the Maxent program.  The departments with the highest occurrence of A. seniculus were Antioquia, Meta and Casanare; 69.5% of the departments with reported history of yellow fever had co-occurrence with A. seniculus. The ecological niche model showed that Antioquia, Bolívar, La Guajira, Magdalena, Meta, Santander, Norte de Santander and Vichada had geographical portions with a probability rate nearing to 0.9 (90%).  In 69.5% of the departments with a history of yellow fever there was co-occurrence with A. seniculus, which is relevant because non-human primates play a well-known role as natural reservoirs of the virus, and they might contribute to the occurrence of the yellow fever, which makes them very useful as sentinels.

  8. Fever During Pregnancy Tied to Autism in Study

    Science.gov (United States)

    ... study cannot prove that a fever during pregnancy causes autism, only that there appears to be an association. ... it's the fever that's predisposing the baby to autism or the cause of the fever or the body's immune response ...

  9. Pancreatic disturbances and typhoid fever.

    Science.gov (United States)

    Hermans, P; Gerard, M; van Laethem, Y; de Wit, S; Clumeck, N

    1991-01-01

    During an 8-year period, 14 adult patients were hospitalized with typhoid fever confirmed by positive blood cultures for Salmonella typhi. Among these patients, we have retrospectively (n = 7) and prospectively (n = 7) evaluated pancreatic disturbance by serum amylase and lipase measurements at the time of admission. In 7 (50%) biological signs of pancreatitis were noted: mean amylase level 81 IU (range 30-201 IU, normal value less than 40 IU), mean lipase level 949 IU (range 468-2,000 IU, normal value less than 300 IU). Clinical signs of pancreatitis were observed in 4 cases, one of whom had a concomitant salmonella biliary tract infection and gall stones demonstrated by laparotomy and the others a normal biliary ultrasonographic examination with a swelling of the pancreas. No alcohol or drug use or other infection were noted before admission. This study suggests that biological or clinical pancreatitis should be considered as a frequent complication of typhoid fever. S. typhi should therefore be added to the list of pathogens implicated in the pathogenesis of non-alcoholic or non-lithiasic pancreatitis.

  10. Leptospirosis presenting as honeymoon fever.

    Science.gov (United States)

    de Sainte Marie, B; Delord, M; Dubourg, G; Gautret, P; Parola, P; Brouqui, P; Lagier, J C

    2015-05-01

    An increasing number of travelers from western countries visit tropical regions, questioning western physicians on the prophylaxis, the diagnosis and the therapeutic management of patients with travel-associated infection. In July 2014, a French couple stayed for an adventure-travel in Columbia without malaria prophylaxis. A week after their return the woman presented with fever, myalgia, and retro-orbital pain. Three days later, her husband presented similar symptoms. In both patients, testing for malaria, arboviruses and blood cultures remained negative. An empirical treatment with doxycycline and ceftriaxone was initiated for both patients. Serum collected from the female patient yielded positive IgM for leptospirosis but was negative for her husband. Positive Real-Time PCR were observed in blood and urine from both patients, confirming leptospirosis. Three lessons are noteworthy from this case report. First, after exclusion of malaria, as enteric fever, leptospirosis and rickettsial infection are the most prevalent travel-associated infections, empirical treatment with doxycycline and third generation cephalosporin should be considered. In addition, the diagnosis of leptospirosis requires both serology and PCR performed in both urine and blood samples. Finally, prophylaxis using doxycycline, also effective against leptospirosis, rickettsial infections or travellers' diarrhea should be recommended for adventure travelers in malaria endemic areas. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Dark Valley in Newton Crater

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-418, 11 July 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) high resolution image shows part of a dark-floored valley system in northern Newton Crater. The valley might have been originally formed by liquid water; the dark material is probably sand that has blown into the valley in more recent times. The picture was acquired earlier this week on July 6, 2003, and is located near 39.2oS, 157.9oW. The picture covers an area 2.3 km (1.4 mi) across; sunlight illuminates the scene from the upper left.

  12. Educational Fever and South Korean Higher Education

    Science.gov (United States)

    Lee, Jeong-Kyu

    2006-01-01

    This paper examines the influence of educational fever on the development of the Republic of Korea education and economy in the context of the cultural history of this country. In order to examine this study, the author explains the concept of educational fever and discusses the relation between Confucianism and education zeal. Educational fever…

  13. Rocky Mountain spotted fever in children.

    Science.gov (United States)

    Woods, Charles R

    2013-04-01

    Rocky Mountain spotted fever is typically undifferentiated from many other infections in the first few days of illness. Treatment should not be delayed pending confirmation of infection when Rocky Mountain spotted fever is suspected. Doxycycline is the drug of choice even for infants and children less than 8 years old. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Typhoid Fever: Misdiagnosis or Overdiagnosis | Onyekwere ...

    African Journals Online (AJOL)

    Recently there has been a public panic about an increase in cases of typhoid fever. Typhoid fever caused by salmonella typhi is common and constitutes a major public health problem in developing countries including sub-Saharan Africa, South America and parts of Asia. Its clinical features are non-specific and available ...

  15. Chronic Q fever in The Netherlands

    NARCIS (Netherlands)

    Kampschreur, L.M.|info:eu-repo/dai/nl/344824497

    2013-01-01

    From 2007-2010, during the recent Q fever epidemic in the Netherlands, over 4000 cases of acute Q fever were registered, which is an underestimation of the total amount of Coxiella burnetii infections due to a high amount of asymptomatic primary infections. In the literature it is stated that 1-5%

  16. The immune response in Q fever

    NARCIS (Netherlands)

    Schoffelen, T.

    2015-01-01

    Q fever is an infection caused by the bacterium Coxiella burnetii. A large outbreak of Q fever occurred in the Netherlands between 2007 and 2010, in which infected goats and sheep were the source of human infections. In some people, so-called ‘chronic Q fever’ develops, which mainly manifests as

  17. Ecological diversity

    National Research Council Canada - National Science Library

    Pielou E. C

    1975-01-01

    The richness and variety-in a word, the diversity-of natural ecological communities have never been more highly valued than they are now, as they become increasingly threatened by the environmental crisis...

  18. Cognitive ecology.

    Science.gov (United States)

    Hutchins, Edwin

    2010-10-01

    Cognitive ecology is the study of cognitive phenomena in context. In particular, it points to the web of mutual dependence among the elements of a cognitive ecosystem. At least three fields were taking a deeply ecological approach to cognition 30 years ago: Gibson's ecological psychology, Bateson's ecology of mind, and Soviet cultural-historical activity theory. The ideas developed in those projects have now found a place in modern views of embodied, situated, distributed cognition. As cognitive theory continues to shift from units of analysis defined by inherent properties of the elements to units defined in terms of dynamic patterns of correlation across elements, the study of cognitive ecosystems will become an increasingly important part of cognitive science. Copyright © 2010 Cognitive Science Society, Inc.

  19. Community Ecology

    CERN Document Server

    1988-01-01

    This book presents the proceedings of a workshop on community ecology organized at Davis, in April, 1986, sponsored by the Sloan Foundation. There have been several recent symposia on community ecology (Strong et. al., 1984, Diamond and Case, 1987) which have covered a wide range of topics. The goal of the workshop at Davis was more narrow: to explore the role of scale in developing a theoretical approach to understanding communities. There are a number of aspects of scale that enter into attempts to understand ecological communities. One of the most basic is organizational scale. Should community ecology proceed by building up from population biology? This question and its ramifications are stressed throughout the book and explored in the first chapter by Simon Levin. Notions of scale have long been important in understanding physical systems. Thus, in understanding the interactions of organisms with their physical environment, questions of scale become paramount. These more physical questions illustrate the...

  20. Educational Fever and South Korean Higher Education

    Directory of Open Access Journals (Sweden)

    Jeong-Kyu Lee

    2006-05-01

    Full Text Available This paper examines the influence of educational fever on the development of the Republic of Korea education and economy in the context of the cultural history of this country. In order to examine this study, the author explains the concept of educational fever and discusses the relation between Confucianism and education zeal. Educational fever and human capitalization in South Korean higher education are analyzed from a comparative viewpoint. The study evaluates the effects and problems of education fever this country’s current higher education, and it concludes that Koreans’ educational fever has been a core factor by which to achieve the development of the national economy as well as the rapid expansion of higher education.

  1. Rat Bite Fever Resembling Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Ripa Akter

    2016-01-01

    Full Text Available Rat bite fever is rare in Western countries. It can be very difficult to diagnose as blood cultures are typically negative and a history of rodent exposure is often missed. Unless a high index of suspicion is maintained, the associated polyarthritis can be mistaken for rheumatoid arthritis. We report a case of culture-positive rat bite fever in a 46-year-old female presenting with fever and polyarthritis. The clinical presentation mimicked rheumatoid arthritis. Infection was complicated by discitis, a rare manifestation. We discuss the diagnosis and management of this rare zoonotic infection. We also review nine reported cases of rat bite fever, all of which had an initial presumptive diagnosis of a rheumatological disorder. Rat bite fever is a potentially curable infection but can have a lethal course if left untreated.

  2. Typhoid fever: the experience of last decade

    Directory of Open Access Journals (Sweden)

    A. N. Kovalenko

    2009-01-01

    Full Text Available This article is about analyses of diagnostics and treatment of the modern typhoid fever. In the past typhoid fever was critical and lifethreatening inflectional disease. But nowadays thanks to using of chloramphenicol and other antimicrobial preparations, typhoid fever is serious but well curable disease. In the second part of the 20th century the number of typhoid fever cases has decreased. As a result a new generation of physicians, who has never come across this disease, appeared. Nowadays typhoid fever is still actual for practical public health in Russia. There are two causes: first, there is a risk of delivery of infections with tourists and immigrants. Second, the small number of physicians, who possess well knowledge of clinical features and modern therapy.

  3. The geographical distribution of Q fever.

    Science.gov (United States)

    KAPLAN, M M; BERTAGNA, P

    1955-01-01

    The results of a WHO-assisted survey of the distribution of Q fever in 32 countries and an analysis of reports published to date indicate that Q fever exists in 51 countries on five continents. Q-fever infection was most often reported in man and the domestic ruminants, such as cattle, sheep, and goats.The disease was found to exist in most countries where investigations were carried out. Notable exceptions were Ireland, the Netherlands, New Zealand, Poland, and the Scandinavian countries. With the exception of Poland, where the results were inconclusive, all these countries import relatively few domestic ruminants-the most important animal reservoirs of human Q-fever infection. It seems, therefore, that the traffic of infected ruminants may be one of the most important, if not the most important, means for the geographical spread of Q fever. The importance, if any, of ticks associated with such traffic needs to be defined.

  4. The Distribution and Identity of Edaphic Fungi in the McMurdo Dry Valleys

    Directory of Open Access Journals (Sweden)

    Lisa L. Dreesens

    2014-07-01

    Full Text Available Contrary to earlier assumptions, molecular evidence has demonstrated the presence of diverse and localized soil bacterial communities in the McMurdo Dry Valleys of Antarctica. Meanwhile, it remains unclear whether fungal signals so far detected in Dry Valley soils using both culture-based and molecular techniques represent adapted and ecologically active biomass or spores transported by wind. Through a systematic and quantitative molecular survey, we identified significant heterogeneities in soil fungal communities across the Dry Valleys that robustly correlate with heterogeneities in soil physicochemical properties. Community fingerprinting analysis and 454 pyrosequencing of the fungal ribosomal intergenic spacer region revealed different levels of heterogeneity in fungal diversity within individual Dry Valleys and a surprising abundance of Chytridiomycota species, whereas previous studies suggested that Dry Valley soils were dominated by Ascomycota and Basidiomycota. Critically, we identified significant differences in fungal community composition and structure of adjacent sites with no obvious barrier to aeolian transport between them. These findings suggest that edaphic fungi of the Antarctic Dry Valleys are adapted to local environments and represent an ecologically relevant (and possibly important heterotrophic component of the ecosystem.

  5. Geographic patterns and environmental factors associated with human yellow fever presence in the Americas.

    Directory of Open Access Journals (Sweden)

    Patricia Najera Hamrick

    2017-09-01

    Full Text Available In the Americas, yellow fever virus transmission is a latent threat due to the proximity between urban and wild environments. Although yellow fever has nearly vanished from North and Central America, there are still 13 countries in the Americas considered endemic by the World Health Organization. Human cases usually occur as a result of the exposure to sylvatic yellow fever in tropical forested environments; but urban outbreaks reported during the last decade demonstrate that the risk in this environment still exists. The objective of this study was to identify spatial patterns and the relationship between key geographic and environmental factors with the distribution of yellow fever human cases in the Americas.An ecological study was carried out to analyze yellow fever human cases reported to the Pan American Health Organization from 2000 to 2014, aggregated by second administrative level subdivisions (counties. Presence of yellow fever by county was used as the outcome variable and eight geo-environmental factors were used as independent variables. Spatial analysis was performed to identify and examine natural settings per county. Subsequently, a multivariable logistic regression model was built. During the study period, 1,164 cases were reported in eight out of the 13 endemic countries. Nearly 83.8% of these cases were concentrated in three countries: Peru (37.4%, Brazil (28.1% and Colombia (18.4%; and distributed in 57 states/provinces, specifically in 286 counties (3.4% of total counties. Yellow fever presence was significantly associated with altitude, rain, diversity of non-human primate hosts and temperature. A positive spatial autocorrelation revealed a clustered geographic pattern in 138/286 yellow fever positive counties (48.3%.A clustered geographic pattern of yellow fever was identified mostly along the Andes eastern foothills. This risk map could support health policies in endemic countries. Geo-environmental factors associated

  6. RailroadValleySpringfish_CH

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These data identify the areas where final critical habitat for the Railroad Valley springfish (Crenichthys nevadae) occur. The irrigation ditch that is on the north...

  7. Water Hyacinth in the Rift Valley Water Bodies of Ethiopia: Its Distribution, Socioeconomic Importance and Management

    NARCIS (Netherlands)

    Firehun, Y.; Struik, P.C.; Lantinga, E.A.; Taye, T.

    2014-01-01

    A survey was conducted in the Rift Valley water bodies of Ethiopia from 2009 to 2011 to (i) determine the prevalence, agro-ecological distribution and sources of infestation of water hyacinth, (ii) investigate the socio-economic impact of water hyacinth, and (iii) assess changes in its

  8. 76 FR 12365 - Canaan Valley National Wildlife Refuge, Tucker and Grant Counties, WV; Final Comprehensive...

    Science.gov (United States)

    2011-03-07

    ... Highway, Davis, WV 26260-8061. Fax: Attention: Ken Sturm, 304-866-3852. FOR FURTHER INFORMATION CONTACT: Ken Sturm, Acting Refuge Manager, Canaan Valley NWR, 6263 Appalachian Highway, Davis, WV 26260-8061..., interpretation, hunting, and fishing. Management activities include maintaining and perpetuating the ecological...

  9. Winter flooding in Dutch stream valley floodplains: biogeochemical effects and vegetation consequences

    NARCIS (Netherlands)

    Beumer, V.

    2009-01-01

    Winter flooding in Dutch stream valley floodplains: biogeochemical effects and vegetation consequences Victor Beumer Climatic change has great impacts on stream catchments and their ecology. Expectations are that more extreme climate events will result in undesired flooding in stream catchments. In

  10. Mating patterns in a savanna population of valley oak (Quercus labata Neé)

    Science.gov (United States)

    Victoria L. Sork; Frank W. Davis; Rodney J. Dyer; Peter E. Smouse

    2002-01-01

    California valley oak is threatened by landscape alteration and failing recruitment in remnant stands. Its reproductive ecology is a key element of the seedling recruitment process. We first examine the mating system, to determine the extent of inbreeding in a population at Sedgwick Reserve, in Santa Barbara County. We then quantify variation in germination success and...

  11. Fever in pregnancy and offspring head circumference.

    Science.gov (United States)

    Dreier, Julie Werenberg; Strandberg-Larsen, Katrine; Uldall, Peter Vilhelm; Nybo Andersen, Anne-Marie

    2017-12-06

    To examine whether maternal fever during pregnancy is associated with reduced head circumference and risk of microcephaly at birth. A prospective study of 86,980 live-born singletons within the Danish National Birth Cohort was carried out. Self-reported maternal fever exposure was ascertained in two interviews during pregnancy and information on head circumference at birth was extracted from the Danish Medical Birth Registry. Fever in pregnancy was reported by 27% of the mothers, and we identified 3370 cases of microcephaly (head circumference less than or equal to third percentile for sex and gestational age) and 1140 cases of severe microcephaly (head circumference less than or equal to first percentile for sex and gestational age). In this study, maternal fever exposure was not associated with reduced head circumference (adjusted β = 0.03, 95% confidence intervals [CI]: 0.01-0.05), increased risk of microcephaly (odds ratio: 0.95, 95% CI: 0.88-1.03) nor severe microcephaly (odds ratio: 1.01, 95% CI: 0.88-1.15) in the offspring. These findings were consistent for increasing numbers of fever episodes, for increasing fever severity, and for exposure in both early pregnancy and midpregnancy. In this most comprehensive study to date, we found no indication that maternal fever in pregnancy is associated with small head size in the offspring. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Fluoroquinolones for treating typhoid and paratyphoid fever (enteric fever).

    Science.gov (United States)

    Effa, Emmanuel E; Lassi, Zohra S; Critchley, Julia A; Garner, Paul; Sinclair, David; Olliaro, Piero L; Bhutta, Zulfiqar A

    2011-10-05

    Typhoid and paratyphoid are febrile illnesses, due to a bacterial infection, which remain common in many low- and middle-income countries. The World Health Organization (WHO) currently recommends the fluoroquinolone antibiotics in areas with known resistance to the older first-line antibiotics. To evaluate fluoroquinolone antibiotics for treating children and adults with enteric fever. We searched The Cochrane Infectious Disease Group Specialized Register (February 2011); Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library (2011, Issue 2); MEDLINE (1966 to February 2011); EMBASE (1974 to February 2011); and LILACS (1982 to February 2011). We also searched the metaRegister of Controlled Trials (mRCT) in February 2011. Randomized controlled trials examining fluoroquinolone antibiotics, in people with blood, stool or bone marrow culture-confirmed enteric fever. Two authors independently assessed the trial's methodological quality and extracted data. We calculated risk ratios (RR) for dichotomous data and mean difference for continuous data with 95% confidence intervals (CI).Comparative effectiveness has been interpreted in the context of; length of treatment, dose, year of study, known levels of antibiotic resistance, or proxy measures of resistance such as the failure rate in the comparator arm. Twenty-six studies, involving 3033 patients, are included in this review.Fluoroquinolones versus older antibiotics (chloramphenicol, co-trimoxazole, amoxicillin and ampicillin)In one study from Pakistan in 2003-04, high clinical failure rates were seen with both chloramphenicol and co-trimoxazole, although resistance was not confirmed microbiologically. A seven-day course of either ciprofloxacin or ofloxacin were found to be superior. Older studies of these comparisons failed to show a difference (six trials, 361 participants).In small studies conducted almost two decades ago, the fluoroquinolones were demonstrated to have fewer

  13. Information Ecology

    DEFF Research Database (Denmark)

    Christiansen, Ellen Tove

    2006-01-01

    The paper describes a pedagogical didactical paradigm for teaching student-designers how to deal with context issues. Form/context-relationships are conceptualized as information ecologies and described as behavioral settings using a key concept developed by social psychologist R.A. Baker...... in the 1960ties, and chosen here because it integrates cultural and psychological trajectories in a theory of living settings. The pedagogical-didactical paradigm comprises three distinct information ecologies, named after their intended outcome: the problem-setting, the exploration-setting, and the fit......-setting. It is specified how context issues can be treated within each of these information ecologies. The paper concludes by discussing the outcome of applying this paradigm with respect to the student-designers’ competence as reflective practitioners....

  14. Anterior ischemic optic neuropathy following dengue fever.

    Science.gov (United States)

    Ramakrishnan, Reshma; Shrivastava, Saurabh; Deshpande, Shrikant; Patkar, Priyanka

    2016-01-01

    Dengue fever is caused by a flavivirus. This infection is endemic in the tropics and warm temperate regions of the world. Ocular manifestations of dengue fever include subconjunctival, vitreous, and retinal haemorrhages; posterior uveitis; optic neuritis; and maculopathies, haemorrhage, and oedema. However anterior ischemic optic neuropathy is a rare presentation. Optic nerve ischemia most frequently occurs at the optic nerve head, where structural crowding of nerve fibers and reduction of the vascular supply may combine to impair perfusion to a critical degree and produce optic disc oedema. Here we present a case of anterior ischemic optic neurapathy associated with dengue fever.

  15. Appendicular perforation in dengue fever: our experience

    Directory of Open Access Journals (Sweden)

    Gunjan Desai

    2014-09-01

    Full Text Available Dengue viral infections have become one of major emerging infectious diseases in the tropics. Acute abdomen occurring in dengue viral infection is not uncommon. The spectrums of acute surgical emergencies which raise suspicion of an abdominal catastrophe in patients presenting with dengue fever include acute pancreatitis, acute acalculous cholecystitis, non-specific peritonitis and very rarely acute appendicitis. The presence of low white cell count and platelet count can raise suspicion of a diagnosis of dengue in a patient presenting with acute abdominal pain, during a dengue epidemic. We herein report three patients with dengue fever who had appendicular perforation during the course of their viral fever.

  16. Lassa fever: another threat from West Africa.

    Science.gov (United States)

    Brosh-Nissimov, Tal

    2016-01-01

    Lassa fever, a zoonotic viral infection, is endemic in West Africa. The disease causes annual wide spread morbidity and mortality in Africa, and can be imported by travelers. Possible importation of Lassa fever and the potential for the use of Lassa virus as an agent of bioterrorism mandate clinicians in Israel and other countries to be vigilant and familiar with the basic characteristics of this disease. The article reviews the basis of this infection and the clinical management of patients with Lassa fever. Special emphasis is given to antiviral treatment and infection control.

  17. Epidural Labor Analgesia and Maternal Fever.

    Science.gov (United States)

    Sharpe, Emily E; Arendt, Katherine W

    2017-06-01

    Women receiving an epidural for labor analgesia are at increased risk for intrapartum fever. This relationship has been supported by observational, before and after, and randomized controlled trials. The etiology is not well understood but is likely a result of noninfectious inflammation as studies have found women with fever have higher levels of inflammatory markers. Maternal pyrexia may change obstetric management and women are more likely to receive antibiotics or undergo cesarean delivery. Maternal pyrexia is associated with adverse neonatal outcomes. With these consequences, understanding and preventing maternal fever is imperative.

  18. [Ebola and Marburg hemorrhagic fever viruses: update on filoviruses].

    Science.gov (United States)

    Leroy, E; Baize, S; Gonzalez, J P

    2011-04-01

    The Ebola and Marburg viruses are the sole members of the Filoviridae family of viruses. They are characterized by a long filamentous form that is unique in the viral world. Filoviruses are among the most virulent pathogens currently known to infect humans. They cause fulminating disease characterized by acute fever followed by generalized hemorrhagic syndrome that is associated with 90% mortality in the most severe forms. Epidemic outbreaks of Marburg and Ebola viruses have taken a heavy toll on human life in Central Africa and devastated large ape populations in Gabon and Republic of Congo. Since their discovery in 1967 (Marburg) and 1976 (Ebola), more than 2,300 cases and 1,670 deaths have been reported. These numbers pale in comparison with the burden caused by malnutrition or other infectious disease scourges in Africa such as malaria, cholera, AIDS, dengue or tuberculosis. However, due to their extremely high lethality, association with multifocal hemorrhaging and specificity to the African continent, these hemorrhagic fever viruses have given rise to great interest on the part not only of the international scientific community but also of the general public because of their perceived potential as biological weapons. Much research has been performed on these viruses and major progress has been made in knowledge of their ecology, epidemiology and physiopathology and in development of vaccine candidates and therapeutic schemes. The purpose of this review is to present the main developments in these particular fields in the last decade.

  19. Borrelia miyamotoi: a widespread tick-borne relapsing fever spirochete.

    Science.gov (United States)

    Wagemakers, Alex; Staarink, Pieter J; Sprong, Hein; Hovius, Joppe W R

    2015-06-01

    Borrelia miyamotoi is a relapsing fever spirochete that has only recently been identified as a human pathogen. Borrelia miyamotoi is genetically and ecologically distinct from Borrelia burgdorferi sensu lato, while both are present in Ixodes ticks. Over 50 patients with an acute febrile illness have been described with a B. miyamotoi infection, and two infected immunocompromised patients developed a meningoencephalitis. Seroprevalence studies indicate exposure in the general population and in specific risk groups, such as patients initially suspected of having human granulocytic anaplasmosis. Here, we review the available literature on B. miyamotoi, describing its presence in ticks, reservoir hosts, and humans, and discussing its potential impact on public health. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Clinical Features Of Malaria And Typhoid Fever | Mba | Journal of ...

    African Journals Online (AJOL)

    Features to distinguish Malaria from Typhoid fever. These can be discerned from a good and detailed clinical history, in addition to a thorough physical examination. The following would help. The paroxysms of malaria fever as against the step ladder pattern fever of typhoid fever. The prominence of headaches in typhoid ...

  1. Trash Ecology

    Science.gov (United States)

    Lind, Georgia J.

    2004-01-01

    A hands on activity involving density, frequency and biomass using transects, quadrats and a local good deed by cleaning up the neighborhood while practicing important techniques in ecology is detailed. The activity is designed for KCC-STEP, whose primary goal is to expand the scientific knowledge and research experiences of their students, who…

  2. Ecological restoration

    Science.gov (United States)

    Christopher D. Barton; John I. Blake; Donald W. Imm

    2005-01-01

    The long history of human settlement, agriculture, and industry at the Savannah River Site (SRS) has created extensive opportunities for ecological restoration. Two hundred years of farming, drainage, dam construction, stream channeling, fire protection, subsistence hunting and fishing, exotic animal and plant introduction, and selective timber harvesting have caused...

  3. Visual ecology

    National Research Council Canada - National Science Library

    Cronin, Thomas W; Johnsen, Sönke; Marsahll, N. Justin; Warrant, Eric

    2014-01-01

    ... ecology. . Physiology, Comparative. . Eye- Evolution. I. Title. QP.C  .'- dc British Library Cataloging-in-Publication Data is available This book...

  4. Transfusion support in patients with dengue fever.

    Science.gov (United States)

    Kaur, Paramjit; Kaur, Gagandeep

    2014-09-01

    Dengue fever has emerged as a global public health problem in the recent decades. The clinical spectrum of the disease ranges from dengue fever to dengue hemorrhagic fever and dengue shock syndrome. The disease is characterized by increased capillary permeability, thrombocytopenia and coagulopathy. Thrombocytopenia with hemorrhagic manifestations warrants platelet transfusions. There is lack of evidence-based guidelines for transfusion support in patients with dengue fever. This contributes to inappropriate use of blood components and blood centers constantly face the challenge of inventory management during dengue outbreaks. The current review is aimed to highlight the role of platelets and other blood components in the management of dengue. The review was performed after searching relevant published literature in PubMed, Science Direct, Google scholar and various text books and journal articles.

  5. Scarlet Fever: A Group A Streptococcal Infection

    Science.gov (United States)

    ... uses them Stay home from work, school, or daycare until you no longer have a fever and ... last updated: January 22, 2018 Content source: National Center for Immunization and Respiratory Diseases , Division of Bacterial ...

  6. Rocky Mountain Spotted Fever (For Parents)

    Science.gov (United States)

    ... Safety for the Whole Family Evaluate Your Child's Lyme Disease Risk Lyme Disease Lyme Disease Hey! A Tick Bit Me! Bug Bites and Stings Rocky Mountain Spotted Fever Lyme Disease Contact Us Print Resources Send to a Friend ...

  7. Acute cerebellar ataxia in enteric fever.

    Science.gov (United States)

    Sawhney, I M; Prabhakar, S; Dhand, U K; Chopra, J S

    1986-01-01

    Acute cerebellar ataxia as an isolated neurological manifestation of enteric fever is very rare. Three cases of acute cerebellar ataxia associated with enteric fever are reported. The diagnosis of enteric fever was confirmed by positive blood culture, strongly positive Widal test and rising antibody titres. The major clinical features were rapid development of gait ataxia, limb ataxia and dysarthria. None of the patients had altered sensorium. The cerebellar involvement was noticed on the second or third day of fever which progressed for one to two days. The symptoms remained static for one to two weeks and thereafter all the patients showed gradual recovery in a few weeks. Acute onset of cerebellar lesion, self limiting course and cerebrospinal fluid pleocytosis suggest par- or post-infectious demyelinating pathology in these patients, who were not related to each other.

  8. THE MEANING OF FEVER IN CHILDREN

    Directory of Open Access Journals (Sweden)

    A. S. Polyakova

    2015-01-01

    Full Text Available Fever is a normal physiological response to illness in young children and it is often associated with a self-limiting viral infection. Fever is not a diagnosis, but a symptom of illness. A diagnosis of the underlying illness is essential to institute appropriate treatment. Although it is a normal response, that facilitates and accelerates recovery, some people, including many doctors, believe that fever should be treated to reduce temperature without determining the underlying illness causing the fever. Antipyretics should be used to make the child more comfortable and not used routinely with the sole aim of reducing the temperature. This article aims to acquaint primary healthcare workers and general practitioners with last guidelines to assist the measurement of body temperature, deciding on when to refer and the appropriate use of antipyretic medication in children, efficacy and safety of paracetamol and ibuprofen in oral and rectal forms. 

  9. Biological control of cattle fever ticks

    Science.gov (United States)

    Cattle fever ticks (CFT) Rhipicephalus microplus and Rhipicephalus annulatus are invasive livestock pests that are endemic to Mexico and invasive along the Texas – Mexico border. Acaricide resistance, alternate wildlife hosts, and pathogenic landscape forming weeds present challenges for sustainable...

  10. Causes of Fever in Rural Southern Laos.

    Science.gov (United States)

    Mayxay, Mayfong; Sengvilaipaseuth, Onanong; Chanthongthip, Anisone; Dubot-Pérès, Audrey; Rolain, Jean-Marc; Parola, Philippe; Craig, Scott B; Tulsiani, Suhella; Burns, Mary-Anne; Khanthavong, Maniphone; Keola, Siamphay; Pongvongsa, Tiengkham; Raoult, Didier; Dittrich, Sabine; Newton, Paul N

    2015-09-01

    The etiology of fever in rural Lao People's Democratic Republic (Laos) has remained obscure until recently owing to the lack of laboratory facilities. We conducted a study to determine the causes of fever among 229 patients without malaria in Savannakhet Province, southern Laos; 52% had evidence of at least one diagnosis (45% with single and 7% with apparent multiple infections). Among patients with only one diagnosis, dengue (30.1%) was the most common, followed by leptospirosis (7.0%), Japanese encephalitis virus infection (3.5%), scrub typhus (2.6%), spotted fever group infection (0.9%), unspecified flavivirus infection (0.9%), and murine typhus (0.4%). We discuss the empirical treatment of fever in relation to these findings. © The American Society of Tropical Medicine and Hygiene.

  11. Typhoid Fever: The Challenges of Medical Management

    African Journals Online (AJOL)

    Typhoid Fever: The Challenges of Medical Management. Dr J A Otegbayo. Gastrointeslinal/ Liver Unit, Department of Medicine,. University oflbaa'an/ University College Hospital, Ibadan, Nigeria. Keywords: Typhoid, medical management, challenges. INTRODUCTION. Salmonella enterica serotype typhi is the aetiological.

  12. A case of ADEM following Chikungunya fever.

    Science.gov (United States)

    Maity, Pranab; Roy, Pinaki; Basu, Arindam; Das, Biman; Ghosh, U S

    2014-05-01

    Chikungunya most often is a self-limiting febrile illness with polyarthritis and the virus is not known to be neurotropic. We are reporting a case of chikugunya fever presenting as acute demyelinating encephalomyelitis(ADEM) which is very rare.

  13. Fever of unknown origin in rheumatic diseases.

    Science.gov (United States)

    Zenone, Thierry

    2007-12-01

    Noninfectious inflammatory diseases (connective tissue diseases, vasculitis syndromes, granulomatous diseases) emerged as the most frequent cause of fever of unknown origin in western countries. Among these diseases, giant cell arteritis and polymyalgia rheumatica are the most frequent specific diagnosis in the elderly and adult-onset Still's disease the most frequent in younger patients. This article focuses on noninfectious inflammatory diseases as a cause of classic fever of unknown origin (mainly rheumatic diseases, such as vasculitis and connective tissue diseases).

  14. Acute atrial fibrillation during dengue hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    Veloso Henrique Horta

    2003-01-01

    Full Text Available Dengue fever is a viral infection transmitted by the mosquito, Aedes aegypti. Cardiac rhythm disorders, such as atrioventricular blocks and ventricular ectopic beats, appear during infection and are attributed to viral myocarditis. However, supraventricular arrhythmias have not been reported. We present a case of acute atrial fibrillation, with a rapid ventricular rate, successfully treated with intravenous amiodarone, in a 62-year-old man with dengue hemorrhagic fever, who had no structural heart disease.

  15. STUDIES ON SOUTH AMERICAN YELLOW FEVER

    Science.gov (United States)

    Davis, Nelson C.; Shannon, Raymond C.

    1929-01-01

    Yellow fever virus from M. rhesus has been inoculated into a South American monkey (Cebus macrocephalus) by blood injection and by bites of infected mosquitoes. The Cebus does not develop the clinical or pathological signs of yellow fever. Nevertheless, the virus persists in the Cebus for a time as shown by the typical symptoms and lesions which develop when the susceptible M. rhesus is inoculated from a Cebus by direct transfer of blood or by mosquito (A. aegypti) transmission. PMID:19869607

  16. The challenge of enteric fever.

    Science.gov (United States)

    Waddington, Claire S; Darton, Thomas C; Pollard, Andrew J

    2014-01-01

    Enteric fever, a non-specific, systemic infection caused by S. Typhi or Paratyphi A, B or C, is common in resource-limited regions of the world, where poor sanitation infrastructure facilitates faeco-oral transmission. Prompt treatment with appropriate antibiotics minimises illness severity, but presentation to health care facilities is often delayed because of the non-specific nature of the symptoms and the lack of reliable diagnostic tests. Disease prevention requires significant investment in provision of clean water and sanitation in the long term; vaccination offers a more realistic strategy for medium term control. However, implementation of existing vaccines and development of more efficacious vaccines has been hindered by the lack of an established correlate of protection and under appreciation of the true disease burden. Human microbial infection studies could provide a vehicle for the rapid evaluation of novel vaccines and investigation of the immunobiology of enteric infection. Copyright © 2013 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  17. Typhoid fever: clinical diagnosis versus laboratory confirmation.

    Science.gov (United States)

    Ngwu, B A; Agbo, J A

    2003-01-01

    Recently there has been an increase in the clinically diagnosed typhoid fever in various parts of Nigeria with subsequent increase in public fear of possible epidemics of the disease. In this study the accuracy of clinically diagnosed typhoid fever were investigated. Blood and stool specimens from 260 patients clinically diagnosed typhoid fever were investigated using Widal test and bacteriological culture methods respectively. One hundred and thirty-four (51.5%) of the cases investigated were positive and that there was a significant difference (P clinically diagnosed and bacteriologically confirmed typhoid fever cases. Causative organisms were Salmonella typhi 46 (34.3%); S paratyphi B 34 (25.4%); S paratyphi A 24 (17.9%); S paratyphi C 20 (14.9%); other Salmonella spp 10 (7.5%). Young adults and males were predominantely affected. Most of the clinically diagnosed typhoid cases were misdiagnosis and the hue and cry by the general public on the epidemic of typhoid fever could not be justified. It is recommended that careful detailed history taking, meticulous clinical examination and prompt bacteriological culturing of specimens from suspected typhoid cases will improve the accuracy of clinically diagnosed typhoid fever.

  18. Ecological risk assessment of heavy metals pollution on irrigated ...

    African Journals Online (AJOL)

    This paper assessed the heavy metals pollution in irrigated soil of salanta river valley of Sharada industrial area with aim of assessing the potential ecological risk of Cd, Cu, Cr and Zn. Soil samples were collected from five plots randomly selected along the stream and heavy metals (Cd, Cu, Cr and Zn) and pH were ...

  19. Ecology of bottomland oaks in the southeastern United states

    Science.gov (United States)

    Emile S. Gardiner

    2001-01-01

    0aks (Querczrs spp.) are among the most ecologically and economically valued trees of the floodplain forests which occupy the river valleys that dissect the Gulf and Atlantic coastal plains of the southeastem United States. In these floodplain forests, several species from the sections Quercus and Lobarae are commonly found distributed along a gradient of sites ranging...

  20. The place of health and the health of place: dengue fever and urban governance in Putrajaya, Malaysia.

    Science.gov (United States)

    Mulligan, K; Elliott, S J; Schuster-Wallace, C

    2012-05-01

    This case study investigates the connections among urban planning, governance and dengue fever in an emerging market context in the Global South. Key informant interviews were conducted with leading figures in public health, urban planning and governance in the planned city of Putrajaya, Malaysia. Drawing on theories of urban political ecology and ecosocial epidemiology, the qualitative study found the health of place - expressed as dengue-bearing mosquitoes and dengue fever in human bodies in the urban environment - was influenced by the place of health in a hierarchy of urban priorities. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Epidemiological characteristics of Brazilian spotted fever in Minas Gerais State, Brazil, 2000-2008

    Directory of Open Access Journals (Sweden)

    Frederico Figueiredo Amâncio

    2011-10-01

    Full Text Available Brazilian spotted fever is the most common rickettsiosis in Brazil, most prevalent in the States of São Paulo and Minas Gerais. The aim of this study was to describe the epidemiological characteristics of Brazilian spotted fever in Minas Gerais from 2000 to 2008. Of the 132 cases of Brazilian spotted fever, 53 patients died, representing a case-fatality rate of 40.2%. Males predominated, with 78.8% of confirmed cases, and median age was 26.5 years. Absence of rash was associated with increased risk of death (p = 0.005. Greater Metropolitan Belo Horizonte, Rio Doce Valley, and Zona da Mata accounted for 70.6% of the cases, which occurred mainly from May to November. There was an increase in the number of cases, which could suggest an expansion of the disease, but probably resulted from an increase in the health system's diagnostic capacity and sensitivity. Despite this improvement, the case-fatality rate remains high and with no apparent tendency to decrease, thus indicating the need for improved prevention and patient care.

  2. Modelling photochemistry in alpine valleys

    Directory of Open Access Journals (Sweden)

    G. Brulfert

    2005-01-01

    Full Text Available Road traffic is a serious problem in the Chamonix Valley, France: traffic, noise and above all air pollution worry the inhabitants. The big fire in the Mont-Blanc tunnel made it possible, in the framework of the POVA project (POllution in Alpine Valleys, to undertake measurement campaigns with and without heavy-vehicle traffic through the Chamonix and Maurienne valleys, towards Italy (before and after the tunnel re-opening. Modelling is one of the aspects of POVA and should make it possible to explain the processes leading to episodes of atmospheric pollution, both in summer and in winter. Atmospheric prediction model ARPS 4.5.2 (Advanced Regional Prediction System, developed at the CAPS (Center for Analysis and Prediction of Storms of the University of Oklahoma, enables to resolve the dynamics above a complex terrain. This model is coupled to the TAPOM 1.5.2 atmospheric chemistry (Transport and Air POllution Model code developed at the Air and Soil Pollution Laboratory of the Ecole Polytechnique Fédérale de Lausanne. The numerical codes MM5 and CHIMERE are used to compute large scale boundary forcing. This paper focuses on modelling Chamonix valley using 300-m grid cells to calculate the dynamics and the reactive chemistry which makes possible to accurately represent the dynamics in the Chamonix valley (slope and valley winds and to process chemistry at fine scale. The summer 2003 intensive campaign was used to validate the model and to study chemistry. NOy according to O3 reduction demonstrates a VOC controlled regime, different from the NOx controlled regime expected and observed in the nearby city of Grenoble.

  3. EPA Region 1 - Valley Depth in Meters

    Data.gov (United States)

    U.S. Environmental Protection Agency — Raster of the Depth in meters of EPA-delimited Valleys in Region 1. Valleys (areas that are lower than their neighbors) were extracted from a Digital Elevation Model...

  4. Valley evolution by meandering rivers

    Science.gov (United States)

    Limaye, Ajay Brian Sanjay

    Fluvial systems form landscapes and sedimentary deposits with a rich hierarchy of structures that extend from grain- to valley scale. Large-scale pattern formation in fluvial systems is commonly attributed to forcing by external factors, including climate change, tectonic uplift, and sea-level change. Yet over geologic timescales, rivers may also develop large-scale erosional and depositional patterns that do not bear on environmental history. This dissertation uses a combination of numerical modeling and topographic analysis to identify and quantify patterns in river valleys that form as a consequence of river meandering alone, under constant external forcing. Chapter 2 identifies a numerical artifact in existing, grid-based models that represent the co-evolution of river channel migration and bank strength over geologic timescales. A new, vector-based technique for bank-material tracking is shown to improve predictions for the evolution of meander belts, floodplains, sedimentary deposits formed by aggrading channels, and bedrock river valleys, particularly when spatial contrasts in bank strength are strong. Chapters 3 and 4 apply this numerical technique to establishing valley topography formed by a vertically incising, meandering river subject to constant external forcing---which should serve as the null hypothesis for valley evolution. In Chapter 3, this scenario is shown to explain a variety of common bedrock river valley types and smaller-scale features within them---including entrenched channels, long-wavelength, arcuate scars in valley walls, and bedrock-cored river terraces. Chapter 4 describes the age and geometric statistics of river terraces formed by meandering with constant external forcing, and compares them to terraces in natural river valleys. The frequency of intrinsic terrace formation by meandering is shown to reflect a characteristic relief-generation timescale, and terrace length is identified as a key criterion for distinguishing these

  5. Tick bite fever and Q fever — a South African perspective

    African Journals Online (AJOL)

    infection, and a post—Q fever chronic fatigue syndrome has been described. The molecular pathophysiology of ... Chronic Q fever remains challenging to treat. The genera Rickettsia and Coxiella are aerobic ... gene nucleotide sequence homologies have allowed more than. 30 species and subspecies of rickettsiae to be ...

  6. Alterations in the host transcriptome in vitro following Rift Valley fever virus infection

    Science.gov (United States)

    2017-08-02

    segments were 121 converted into a multi-FASTA file. Bowtie213 was used to align trimmed paired-end reads to the viral 122 genomes. Counts of reads...intriguing given that our work was done using lung epithelial cells. Furthermore, non-280 muscle myosin heavy chain IIA (NMMHC-IIA), upregulated in our

  7. Potential for Stable Flies and House Flies (Diptera: Muscidae) to Transmit Rift Valley Fever Virus

    Science.gov (United States)

    2010-01-01

    hundreds of thousands of human infections and major economic disruption due to loss of livestock and to trade restrictions. As indicated by the rapid...that have resulted in hundreds of thousands of human infections and major economic disruption due to loss of livestock and to trade restrictions. As...serum in Medium 199 with Earle’s salts [Invitrogen Inc., Carlsbad, CA] and antibiotics ) and then frozen at 270uC until tested for infectious virus by a

  8. Entomological and Rift Valley Fever Surveillance Support to Operation Bright Star FY94

    Science.gov (United States)

    1994-01-01

    Oryzaephilus surinamensis , 3-specimens (Condemn @ levels > 7/1 lb sample). c. Mouse pellets. #5. Date submitted: 22 NOV 93 Submitted by: Capt L...Tribolium castancum, 21 larvae, 2- adults (Condemn @ levels represented). b. Saw-toothed grain beetle, Oryzaephilus surinamensis , 1-adult. c. ? flour...DET Source of specimens: CDC light trap Identity and importance: a. Mosquitoes, Cx. perexiguus, 2- females . b. Mosquitoes, Cx. pipiens, 2-males/5

  9. Respiratory Infectivity of a Recently Isolated Egyptian Strain of Rift Valley Fever Virus.

    Science.gov (United States)

    1981-04-10

    a-s IOr puppies (11.) , where approximately 25 mouse intracerebral LD 50Were required to induce infection. This is the first time the respirator’ LD...has been estabtlished50 for mnice. A comparable va tue is ava iltable For only, one o t ir 111imai spec ies. Mill er et a t. (18) , us ing p rocecdi

  10. The epidemiology and socio-economic impact of rift valley fever in ...

    African Journals Online (AJOL)

    http://dx.doi.org/10.4314/thrb.v13i5.1 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers ...

  11. 77 FR 68783 - Prospective Grant of Exclusive License: Veterinary Vaccines for Rift Valley Fever Virus

    Science.gov (United States)

    2012-11-16

    ... in the patent applications referred to below to Merial Limited, having a place of business in Duluth... conditions of 35 U.S.C. 209 and 37 CFR 404.7. Technology: The technology allows for the generation of... induce robust protective immunity following the administration of a single vaccine dose in a rat model of...

  12. Single-Molecule FISH Reveals Non-selective Packaging of Rift Valley Fever Virus Genome Segments

    NARCIS (Netherlands)

    Wichgers Schreur, Paul J.; Kortekaas, Jeroen

    2016-01-01

    The bunyavirus genome comprises a small (S), medium (M), and large (L) RNA segment of negative polarity. Although genome segmentation confers evolutionary advantages by enabling genome reassortment events with related viruses, genome segmentation also complicates genome replication and packaging.

  13. The epidemiology and socio-economic impact of rift valley fever in ...

    African Journals Online (AJOL)

    Tanzania Journal of Health Research. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 13, No 5 (2011) >. Log in or Register to get access to full text downloads.

  14. A Fusion-Inhibiting Peptide against Rift Valley Fever Virus Inhibits Multiple, Diverse Viruses

    Science.gov (United States)

    2013-09-12

    infection is severe in animals, especially sheep, cattle, and goats, resulting in high mortality rates in newborns and near 100% abortion rates in...small molecule drugs that could also block infectivity, expanding the utility of these peptides for therapeutics development. Supporting Information

  15. The epidemiology and socio-economic impact of rift valley fever in ...

    African Journals Online (AJOL)

    Tanzania is amongst the countries of the sub-Saharan Africa that have encoutered a number of disease epidemics. Relatively little is known about the trend of occurrence, epidemiological factors and socio-economic impact related to previous epidemics in the country. This review was conducted to provide comprehensive ...

  16. Transstadial and Horizontal Transmission of Rift Valley Fever Virus in Hyalomma truncatum

    Science.gov (United States)

    1989-01-01

    encephalitis virus above IC inoculation levels in fed H. truncatum in Ixodes ricinus are reported to be as low as males which had originally been infected as...disease in ixodes petauristae, 92-99. would not have interfered with our ability to 3. Davies FG, Highton RB, 1980. Possible vectors detect vertical

  17. Studies of Infection and Dissemination of Rift Valley Fever Virus in Mosquitoes.

    Science.gov (United States)

    1991-10-15

    Oxford. Rothschild, M., Y. Schlein & S. Ito. 1986. & Colour Atlas Insect Tissues--Via the Fea. Wolfe Publishing Ltd., London. Smith, D.S. 1968. Insect...borne diseases. Parasitologia 32: 87-111. AVIDIN-BIOTIN IMMUNOCYTOCHEMISTRY FOR PLASTIC SECTIONS AND PEPTIDE IMMUNOCYTOCHEMISTRY FOR ELECTRON

  18. Immunogenicity and Safety of an Inactivated Rift Valley Fever Vaccine in a 19-Year Study

    Science.gov (United States)

    2011-02-26

    5ml of sterile water before injection . A total of 31 lots and runs of the vaccine were administered during the study. 2.2. Serology Immunological...the inoculated cells were overlaid with nutrient medium containing 1% agar, 5% fetal bovine serum, 200U of peni - cillin/ml, and 200mg of streptomycin...always used to complete the primary series). The primary series of the vaccine consisted of three 1.0-ml subcutaneous injections in the triceps region

  19. Yellow fever vaccination in the Americas.

    Science.gov (United States)

    1984-01-01

    Outbreaks of yellow fever in recent years in the Americas have prompted concern about the possible urbanization of jungle fever. Vaccination, using the 17D strain of yellow fever virus, provides an effective, practical method of large scale protection against the disease. Because yellow fever can reappear in certain areas after a 2-year dormancy period, some countries maintain routine vaccination programs in areas where jungle yellow fever is endemic. The size of the endemic area (approximately half of South America), transportation and communication difficulties, and the inability to ensure a reliable cold chain are problems facing these programs. In addition, the problem of reaching dispersed and isolated populations has been addressed by the use of mobile teams, radio monitoring, and educational methods. During yellow fever outbreaks, many countries institute massive vaccination campaigns, targeted at temporary workers and migrants. Because epidemics in South America may involve extensive areas, these campaigns may not effectively address the problem. The ped-o-jet injector method, used in Brazil and Colombia, should be used in outbreak situations, as it is effective for large-scale vaccination. Vaccine by needle, suggested for maintenance programs, should be administered to those above 1 year of age. An efficient monitoring method to avoid revaccination, and to assess immunity, should be developed. The 17D strain produces seroconversion in 95% of recipients, and most is prepared in Brazil and Colombia. But, problems with storage methods, instability in seed lots, and difficulties in large-scale production were identified in 1981 by the Pan American Health Organization and WHO. The group recommended modernization of current production techniques and further research to develop a vaccine that could be produced in cell cultures. Brazil and Colombia have acted on these recommendations, modernizing vaccine production and researching thermostabilizing media for

  20. Chronic Q fever in the Netherlands 5 years after the start of the Q fever epidemic: results from the Dutch chronic Q fever database

    NARCIS (Netherlands)

    Kampschreur, L.M.; Delsing, C.E.; Groenwold, R.H.; Wegdam-Blans, M.C.; Bleeker-Rovers, C.P.; Jager-Leclercq, M.G. De; Hoepelman, A.I.; Kasteren, M.E.E. van; Buijs, J.; Renders, N.H.; Nabuurs-Franssen, M.H.; Oosterheert, J.J.; Wever, P.C.

    2014-01-01

    Coxiella burnetii causes Q fever, a zoonosis, which has acute and chronic manifestations. From 2007 to 2010, the Netherlands experienced a large Q fever outbreak, which has offered a unique opportunity to analyze chronic Q fever cases. In an observational cohort study, baseline characteristics and

  1. Malaria signs and infection rate among asymptomatic schoolchildren in Hajr Valley, Yemen.

    Science.gov (United States)

    Bin Mohanna, M A; Bin Ghouth, A S; Rajaa, Y A

    2007-01-01

    This study recorded malaria signs and the rate of parasitaemia among asymptomatic schoolchildren in Hajr valley, Hadhramout governorate, Yemen. Tests were made for malaria parasites and anaemia in 469 randomly selected primary-school children aged 6-11 years, together with clinical examination to determine spleen size, and interviews to study sociodemographic factors. Of the children, 12.8% had positive malaria blood films and 11.3% had spleen enlargement. There were significant associations between malaria infection, anaemia and splenomegaly and fever. Children with malaria parasitaemia were more often absent from school.

  2. Yellow fever risk assessment in the Central African Republic.

    Science.gov (United States)

    Staples, J Erin; Diallo, Mawlouth; Janusz, Kristen B; Manengu, Casimir; Lewis, Rosamund F; Perea, William; Yactayo, Sergio; Sall, Amadou A

    2014-10-01

    Starting in 2008, the Central African Republic (CAR) experienced an unprecedented number of reported yellow fever (YF) cases. A risk assessment of YF virus (YFV) activity was conducted to estimate potential disease risk and vaccine needs. A multistage cluster sampling design was used to sample humans, non-human primates, and mosquitoes in distinct ecologic zones. Humans and non-human primates were tested for YFV-specific antibodies; mosquitoes were tested for YFV RNA. Overall, 13.3% (125/938) of humans were found to have naturally-acquired YFV antibodies. Antibody levels were higher in zones in the southern and south central regions of CAR. All sampled non-human primates (n=56) were known YFV reservoirs; one tested positive for YFV antibodies. Several known YF vectors were identified including Aedes africanus, Ae. aegypti, Ae. luteocephalus, and Ae. simpsoni. Several more urban locations were found to have elevated Breateau and Container indices for Ae. aegypti. A country-wide assessment of YF risk found YFV to be endemic in CAR. The potential for future YF cases and outbreaks, however, varied by ecologic zone. Improved vaccination coverage through mass campaign and childhood immunization was recommended to mitigate the YF risk. © The Author 2014. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. The hemorrhagic fevers of Southern Africa with special reference to studies in the South African Institute for Medical Research.

    Science.gov (United States)

    Gear, J H

    1982-01-01

    In this review of studies on the hemorrhagic fevers of Southern Africa carried out in the South African Institute for Medical Research, attention has been called to occurrence of meningococcal septicemia in recruits to the mining industry and South African Army, to cases of staphylococcal and streptococcal septicemia with hemorrhagic manifestations, and to the occurrence of plague which, in its septicemic form, may cause a hemorrhagic state. "Onyalai," a bleeding disease in tropical Africa, often fatal, was related to profound thrombocytopenia possibly following administration of toxic witch doctor medicine. Spirochetal diseases, and rickettsial diseases in their severe forms, are often manifested with hemorrhagic complications. Of enterovirus infections, Coxsackie B viruses occasionally caused severe hepatitis associated with bleeding, especially in newborn babies. Cases of hemorrhagic fever presenting in February-March, 1975 are described. The first outbreak was due to Marburg virus disease and the second, which included seven fatal cases, was caused by Rift Valley fever virus. In recent cases of hemorrhagic fever a variety of infective organisms have been incriminated including bacterial infections, rickettsial diseases, and virus diseases, including Herpesvirus hominis; in one patient, the hemorrhagic state was related to rubella. A boy who died in a hemorrhagic state was found to have Congo fever; another patient who died of severe bleeding from the lungs was infected with Leptospira canicola, and two patients who developed a hemorrhagic state after a safari trip in Northern Botswana were infected with Trypanosoma rhodesiense. An illness manifested by high fever and melena developed in a young man after a visit to Zimbabwe; the patient was found to have both malaria and Marburg virus disease.

  4. The Central Valley Hydrologic Model

    Science.gov (United States)

    Faunt, C.; Belitz, K.; Hanson, R. T.

    2009-12-01

    Historically, California’s Central Valley has been one of the most productive agricultural regions in the world. The Central Valley also is rapidly becoming an important area for California’s expanding urban population. In response to this competition for water, a number of water-related issues have gained prominence: conjunctive use, artificial recharge, hydrologic implications of land-use change, subsidence, and effects of climate variability. To provide information to stakeholders addressing these issues, the USGS made a detailed assessment of the Central Valley aquifer system that includes the present status of water resources and how these resources have changed over time. The principal product of this assessment is a tool, referred to as the Central Valley Hydrologic Model (CVHM), that simulates surface-water flows, groundwater flows, and land subsidence in response to stresses from human uses and from climate variability throughout the entire Central Valley. The CVHM utilizes MODFLOW combined with a new tool called “Farm Process” to simulate groundwater and surface-water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis. This model was discretized horizontally into 20,000 1-mi2 cells and vertically into 10 layers ranging in thickness from 50 feet at the land surface to 750 feet at depth. A texture model constructed by using data from more than 8,500 drillers’ logs was used to estimate hydraulic properties. Unmetered pumpage and surface-water deliveries for 21 water-balance regions were simulated with the Farm Process. Model results indicate that human activities, predominately surface-water deliveries and groundwater pumping for irrigated agriculture, have dramatically influenced the hydrology of the Central Valley. These human activities have increased flow though the aquifer system by about a factor of six compared to pre-development conditions. The simulated hydrology reflects spatial

  5. Fever of unknown origin (FUO) revised.

    Science.gov (United States)

    Unger, Manuel; Karanikas, Georgios; Kerschbaumer, Andreas; Winkler, Stefan; Aletaha, Daniel

    2016-11-01

    Fever of unknown origin (FUO) was originally characterised in 1961 by Petersdorf and Beeson as a disease condition of temperature exceeding 38.3 °C on at least three occasions over a period of at least three weeks, with no diagnosis made despite one week of inpatient investigation. However, since underlying diseases are often reported for classical FUO, these presentations may not be considered to be of "unknown origin". Rather, the aetiology of prolonged fever may resolve, or not resolve. The definition of fever with unresolved cause (true FUO) is difficult, as it is a moving target, given the constant advancement of imaging and biomarker analysis. Therefore, the prevalence of fever with unresolved cause (FUO) is unknown.In this review, we report such a case of prolonged fever, which initially has presented as classical FUO, and discuss current literature. Furthermore, we will give an outlook, how a prospective study on FUO will allow to solve outstanding issues like the utility of different diagnostic investigations, and the types and prevalence of various underlying diseases.

  6. A Multiplex PCR/LDR Assay for the Simultaneous Identification of Category A Infectious Pathogens: Agents of Viral Hemorrhagic Fever and Variola Virus.

    Directory of Open Access Journals (Sweden)

    Sanchita Das

    Full Text Available CDC designated category A infectious agents pose a major risk to national security and require special action for public health preparedness. They include viruses that cause viral hemorrhagic fever (VHF syndrome as well as variola virus, the agent of smallpox. VHF is characterized by hemorrhage and fever with multi-organ failure leading to high morbidity and mortality. Smallpox, a prior scourge, has been eradicated for decades, making it a particularly serious threat if released nefariously in the essentially non-immune world population. Early detection of the causative agents, and the ability to distinguish them from other pathogens, is essential to contain outbreaks, implement proper control measures, and prevent morbidity and mortality. We have developed a multiplex detection assay that uses several species-specific PCR primers to generate amplicons from multiple pathogens; these are then targeted in a ligase detection reaction (LDR. The resultant fluorescently-labeled ligation products are detected on a universal array enabling simultaneous identification of the pathogens. The assay was evaluated on 32 different isolates associated with VHF (ebolavirus, marburgvirus, Crimean Congo hemorrhagic fever virus, Lassa fever virus, Rift Valley fever virus, Dengue virus, and Yellow fever virus as well as variola virus and vaccinia virus (the agent of smallpox and its vaccine strain, respectively. The assay was able to detect all viruses tested, including 8 sequences representative of different variola virus strains from the CDC repository. It does not cross react with other emerging zoonoses such as monkeypox virus or cowpox virus, or six flaviviruses tested (St. Louis encephalitis virus, Murray Valley encephalitis virus, Powassan virus, Tick-borne encephalitis virus, West Nile virus and Japanese encephalitis virus.

  7. Fungal Biodiversity in the Alpine Tarfala Valley.

    Science.gov (United States)

    Coleine, Claudia; Selbmann, Laura; Ventura, Stefano; D'Acqui, Luigi Paolo; Onofri, Silvano; Zucconi, Laura

    2015-10-10

    Biological soil crusts (BSCs) are distributed worldwide in all semiarid and arid lands, where they play a determinant role in element cycling and soil development. Although much work has concentrated on BSC microbial communities, free-living fungi have been hitherto largely overlooked. The aim of this study was to examine the fungal biodiversity, by cultural-dependent and cultural-independent approaches, in thirteen samples of Arctic BSCs collected at different sites in the Alpine Tarfala Valley, located on the slopes of Kebnekaise, the highest mountain in northern Scandinavia. Isolated fungi were identified by both microscopic observation and molecular approaches. Data revealed that the fungal assemblage composition was homogeneous among the BSCs analyzed, with low biodiversity and the presence of a few dominant species; the majority of fungi isolated belonged to the Ascomycota, and Cryptococcus gilvescens and Pezoloma ericae were the most frequently-recorded species. Ecological considerations for the species involved and the implication of our findings for future fungal research in BSCs are put forward.

  8. Fungal Biodiversity in the Alpine Tarfala Valley

    Directory of Open Access Journals (Sweden)

    Claudia Coleine

    2015-10-01

    Full Text Available Biological soil crusts (BSCs are distributed worldwide in all semiarid and arid lands, where they play a determinant role in element cycling and soil development. Although much work has concentrated on BSC microbial communities, free-living fungi have been hitherto largely overlooked. The aim of this study was to examine the fungal biodiversity, by cultural-dependent and cultural-independent approaches, in thirteen samples of Arctic BSCs collected at different sites in the Alpine Tarfala Valley, located on the slopes of Kebnekaise, the highest mountain in northern Scandinavia. Isolated fungi were identified by both microscopic observation and molecular approaches. Data revealed that the fungal assemblage composition was homogeneous among the BSCs analyzed, with low biodiversity and the presence of a few dominant species; the majority of fungi isolated belonged to the Ascomycota, and Cryptococcus gilvescens and Pezoloma ericae were the most frequently-recorded species. Ecological considerations for the species involved and the implication of our findings for future fungal research in BSCs are put forward.

  9. Optimal Repellent Usage to Combat Dengue Fever.

    Science.gov (United States)

    Dorsett, Chasity; Oh, Hyunju; Paulemond, Marie Laura; Rychtář, Jan

    2016-05-01

    Dengue fever is one of the most important vector-borne diseases. It is transmitted by Aedes Stegomyia aegypti, and one of the most effective strategies to combat the disease is the reduction of exposure to bites of these mosquitoes. In this paper, we present a game-theoretical model in which individuals choose their own level of protection against mosquito bites in order to maximize their own benefits, effectively balancing the cost of protection and the risk of contracting the dengue fever. We find that even when the usage of protection is strictly voluntary, as soon as the cost of protection is about 10,000 times less than the cost of contracting dengue fever, the optimal level of protection will be within 5 % of the level needed for herd immunity.

  10. Hemophagocytic syndrome in classic dengue fever

    Directory of Open Access Journals (Sweden)

    Sayantan Ray

    2011-01-01

    Full Text Available A 24-year-old previously healthy girl presented with persistent fever, headache, and jaundice. Rapid-test anti-dengue virus IgM antibody was positive but anti-dengue IgG was nonreactive, which is suggestive of primary dengue infection. There was clinical deterioration during empiric antibiotic and symptomatic therapy. Bone marrow examination demonstrated the presence of hemophagocytosis. Diagnosis of dengue fever with virus-associated hemophagocytic syndrome was made according to the diagnostic criteria of the HLH 2004 protocol of the Histiocyte Society. The patient recovered with corticosteroid therapy. A review of literature revealed only a handful of case reports that showed the evidence that this syndrome is caused by dengue virus. Our patient is an interesting case of hemophagocytic syndrome associated with classic dengue fever and contributes an additional case to the existing literature on this topic. This case highlights the need for increased awareness even in infections not typically associated with hemophagocytic syndrome.

  11. Milk fever control principles: a review

    DEFF Research Database (Denmark)

    Thilsing-Hansen, T; Jørgensen, R J; Østergaard, S

    2002-01-01

    with sufficient magnesium to fulfil its needs, and to prevent the dry cows from being too fat. Available information on the influence of carbohydrate intake, and on the effect of the length of the dry period and prepartum milking, is at present insufficient to include these factors in control programmes....... prevention as well as prevention of milk fever relapse after intravenous treatment with calcium solutions. However, some drenches have been shown to cause lesions in the forestomacs. When using the DCAD (dietary cation-anion difference) principle, feeding rations with a negative DCAD (measured as (Na + K...... is a palatability problem. The principle of feeding rations low in calcium is highly efficient in milk fever prevention provided the calcium intake in the dry period is kept below 20 g per day. Calculating the relative risk (RR) of developing milk fever from controlled experiments results in a very low mean RR...

  12. [Rocky Mountain spotted fever in Brazil].

    Science.gov (United States)

    del Sá DelFiol, Fernando; Junqueira, Fábio Miranda; da Rocha, Maria Carolina Pereira; de Toledo, Maria Inês; Filho, Silvio Barberato

    2010-06-01

    Although the number of confirmed cases of spotted fever has been declining in Brazil since 2005, the mortality rate (20% to 30%) is still high in comparison to other countries. This high mortality rate is closely related to the difficulty in making the diagnosis and starting the correct treatment. Only two groups of antibiotics have proven clinical effectiveness against spotted fever: chloramphenicol and tetracyclines. Until recently, the use of tetracyclines was restricted to adults because of the associated bone and tooth changes in children. Recently, however, the American Academy of Pediatrics and various researchers have recommended the use of doxycycline in children. In more severe cases, chloramphenicol injections are often preferred in Brazil because of the lack of experience with injectable tetracycline. Since early diagnosis and the adequate drug treatment are key to a good prognosis, health care professionals must be better prepared to recognize and treat spotted fever.

  13. Clara Maass, yellow fever and human experimentation.

    Science.gov (United States)

    Chaves-Carballo, Enrique

    2013-05-01

    Clara Louise Maass, a 25-year-old American nurse, died of yellow fever on August 24, 1901, following experimental inoculation by infected mosquitoes in Havana, Cuba. The human yellow fever experiments were initially conducted by MAJ Walter Reed, who first used written informed consent and proved the validity of Finlay's mosquito-vector hypothesis. Despite informed consent form and an incentive of $100 in U.S. gold, human subjects were exposed to a deadly virus. The deaths of Clara Maass and two Spanish immigrants resulted in a public outcry and the immediate cessation of yellow fever human experiments in Cuba. Reprint & Copyright © 2013 Association of Military Surgeons of the U.S.

  14. Lost trust: a yellow fever patient response.

    Science.gov (United States)

    Runge, John S

    2013-12-13

    In the 19th century, yellow fever thrived in the tropical, urban trade centers along the American Gulf Coast. Industrializing and populated, New Orleans and Memphis made excellent habitats for the yellow fever-carrying Aedes aegypti mosquitoes and the virulence they imparted on their victims. Known for its jaundice and black, blood-filled vomit, the malady terrorized the region for decades, sometimes claiming tens of thousands of lives during the near annual summertime outbreaks. In response to the failing medical community, a small, pronounced population of sick and healthy laypeople openly criticized the efforts to rid the Gulf region of yellow jack. Utilizing newspapers and cartoons to vocalize their opinions, these critics doubted and mocked the medical community, contributing to the regional and seasonal dilemma yellow fever posed for the American South. These sentient expressions prove to be an early example of patient distrust toward caregivers, a current problem in clinical heath care.

  15. [Borrelia miyamotoi: a recently identified human pathogenic tick-borne relapsing fever spirochete].

    Science.gov (United States)

    Szekeres, Sándor; Lakos, András; Földvári, Gábor

    2017-07-01

    Borrelia miyamotoi is a recently described relapsing fever spirochete transmitted by ticks of the Ixodes ricinus complex. This pathogen is different from Borrelia burgdorferi sensu lato (the Lyme borreliosis spirochetes) in its epidemiology, ecology and also genetics. Over 50 patients have been described worldwide with Borrelia miyamotoi disease, and three immunocompromised patients were reported with neurological symptoms. Our knowledge about Borrelia miyamotoi infection in ticks and its distribution in different habitats and also the mechanism of the infection is limited. The most common symptom is fever; thus it can be easily confused with other tick-borne diseases. Due to the intensive research in recent years, Borrelia miyamotoi infection in ticks and hosts has been reported from different regions and also the number of patients is increasing, thus this bacterium is considered as an emerging pathogen. In this literature review we would like to summarize the available knowledge about this spirochete. Orv Hetil. 2017, 158(29): 1124-1130.

  16. Effect of (social) media on the political figure fever model: Jokowi-fever model

    Science.gov (United States)

    Yong, Benny; Samat, Nor Azah

    2016-02-01

    In recent years, political figures begin to utilize social media as one of alternative to engage in communication with their supporters. Publics referred to Jokowi, one of the candidates in Indonesia presidential election in 2014, as the first politician in Indonesia to truly understand the power of social media. Social media is very important in shaping public opinion. In this paper, effect of social media on the Jokowi-fever model in a closed population will be discussed. Supporter population is divided into three class sub-population, i.e susceptible supporters, Jokowi infected supporters, and recovered supporters. For case no positive media, there are two equilibrium points; the Jokowi-fever free equilibrium point in which it locally stable if basic reproductive ratio less than one and the Jokowi-fever endemic equilibrium point in which it locally stable if basic reproductive ratio greater than one. For case no negative media, there is only the Jokowi-fever endemic equilibrium point in which it locally stable if the condition is satisfied. Generally, for case positive media proportion is positive, there is no Jokowi-fever free equilibrium point. The numerical result shows that social media gives significantly effect on Jokowi-fever model, a sharp increase or a sharp decrease in the number of Jokowi infected supporters. It is also shown that the boredom rate is one of the sensitive parameters in the Jokowi-fever model; it affects the number of Jokowi infected supporters.

  17. Chikungunya fever: current status in Mexico

    Directory of Open Access Journals (Sweden)

    Margarita Nava-Frías

    2016-03-01

    Full Text Available Chikungunya fever is a tropical vector-borne disease that has been spreading rapidly around the world during the last 10 years, and which has been usually misdiagnosed as dengue. Nowadays, this disease is increasing in Mexico, mainly in the southern and central zones of the country, being significantly more common in women, children and young adults (28% in < 20 years of age. The classical presentation includes fever, arthralgia, polyarthritis, back-pain, and skin rashes. Although symptoms and treatment are similar to those for dengue, there are key clinical features to differentiate these two diseases.

  18. Milk Fever Control Principles: A Review

    Directory of Open Access Journals (Sweden)

    Østergaard S

    2002-03-01

    Full Text Available Three main preventive principles against milk fever were evaluated in this literature review, and the efficacy of each principle was estimated from the results of controlled investigations. Oral calcium drenching around calving apparently has a mean efficacy of 50%–60% in terms of milk fever prevention as well as prevention of milk fever relapse after intravenous treatment with calcium solutions. However, some drenches have been shown to cause lesions in the forestomacs. When using the DCAD (dietary cation-anion difference principle, feeding rations with a negative DCAD (measured as (Na + K – (Cl + S significantly reduce the milk fever incidence. Calculating the relative risk (RR of developing milk fever from controlled experiments results in a mean RR between 0.19 and 0.35 when rations with a negative versus positive DCAD are compared. The main drawback from the DCAD principle is a palatability problem. The principle of feeding rations low in calcium is highly efficient in milk fever prevention provided the calcium intake in the dry period is kept below 20 g per day. Calculating the relative risk (RR of developing milk fever from controlled experiments results in a very low mean RR (between 0 and 0.20 (daily calcium intake below versus above 20 g/d. The main problem in implementing the low-Ca principle is difficulties in formulating rations sufficiently low in calcium when using commonly available feeds. The use of large doses of vitamin D metabolites and analogues for milk fever prevention is controversial. Due to toxicity problems and an almost total lack of recent studies on the subject this principle is not described in detail. A few management related issues were discussed briefly, and the following conclusions were made: It is important to supply the periparturient cow with sufficient magnesium to fulfil its needs, and to prevent the dry cows from being too fat. Available information on the influence of carbohydrate intake, and on the

  19. Yellow fever vaccine-associated viscerotropic disease.

    Science.gov (United States)

    Rowland, Michael; Plackett, Timothy P; Smith, Richard

    2012-04-01

    Yellow fever is a mosquito-transmitted hemorrhagic viral disease that is endemic to tropical regions in South America and Africa. It remains a significant health concern for deploying military personnel, accordingly vaccination is frequently performed on troops. Although the vaccine is generally administered with only minor complications, rare severe complications are also reported. Herein, we report a mild case of yellow fever vaccine-associated viscerotropic disease 4 days after administration of the vaccine. The various complications of the vaccine and their pathogenesis are also reviewed.

  20. Fever in pregnancy and offspring head circumference

    DEFF Research Database (Denmark)

    Dreier, Julie Werenberg; Strandberg-Larsen, Katrine; Uldall, Peter Vilhelm

    2017-01-01

    was ascertained in two interviews during pregnancy and information on head circumference at birth was extracted from the Danish Medical Birth Registry. RESULTS: Fever in pregnancy was reported by 27% of the mothers, and we identified 3370 cases of microcephaly (head circumference less than or equal to third...... percentile for sex and gestational age) and 1140 cases of severe microcephaly (head circumference less than or equal to first percentile for sex and gestational age). In this study, maternal fever exposure was not associated with reduced head circumference (adjusted β = 0.03, 95% confidence intervals [CI]: 0...