Small

United States Articles found through PubMed 2000-2012

Description

West Nile Virus (WNV) is a mosquito-borne virus that can infect humans. Originally known in East Africa, WNV has now spread throughout the world. The first case of WNV in the western hemisphere was identified in New York in 1999, and within 5 years the disease had spread throughout the United States and into Canada, Latin America, and the Caribbean. While most of WNV infections cause no symptoms, the remaining cases show flu-like symptoms, and can lead to neurological disease or death.

latest article added on November 2013

ArticleFirst AuthorPublished
West Nile Virus Antibodies in Permanent Resident and Overwintering Migrant Birds in South-Central KansasShelite, Thomas R.2008

West Nile Virus Antibodies in Permanent Resident and Overwintering Migrant Birds in South-Central Kansas

Keywords

WNV

Abstract

We conducted serological studies, using epitope-blocking ELISAs directed at West Nile virus (WNV) and flavivirus antibodies, of wild birds in south-central Kansas, the first for this state, in the winters of 2003-04 through 2005-06. Overwintering migratory species (primarily the American tree sparrow and dark-eyed junco) consistently showed significantly lower seropositivity than permanent residents (primarily the northern cardinal). The cardinal showed annual variation in seropositivity between winters. Of 35 birds that were serial sampled within a single winter, one cardinal may have seroconverted between late December and mid-February, providing a preliminary suggestion of continued enzootic transmission, chronic infection, or bird-bird transfer as overwintering mechanisms. Breeding population size of the cardinal did not change after the introduction of WNV to Kansas. Of eighteen birds that were serial sampled between winters, none seroconverted. Among overwintering migrants, the Harris' Sparrow showed the highest seropositivity, possibly related to its migration route through the central Great Plains, an area of recent high WNV activity. The finding that permanent resident birds exhibit higher seropositivity than migrant birds suggests that resident birds contribute to the initiation of annual infection cycles,although this conclusion is speculative in the absence of data on viral titers and the length of viremia. KeyWords: West Nile Virus-flavivirus-birds-epitope-blocking ELISA-winter.

Authors

Shelite, Thomas R., Rogers, Christopher M., Litzner, Brandon R., Johnson, R. Roy and Schneegurt, Mark A.

Year Published

2008

Publication

Vector-Borne and Zoonotic Diseases

Locations
DOI

10.1089/vbz.2007.0176

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18471059

West Nile Virus Antibodies in Bats from New Jersey and New YorkPilipski, Jacob D.2004

West Nile Virus Antibodies in Bats from New Jersey and New York

Keywords

Antibodies, bats, New Jersey, survey, West Nile virus, WNV

Abstract

Eighty-three serum samples were obtained from big brown (Eptesicus fuscus), little brown (Myotis lucifugus), and northern long-eared (Myotis septentrionalis) bats (Chiroptera: Vespertilionidae), from New Jersey and New York (USA) between July and October 2002. Samples were analyzed for neutralizing antibodies to West Nile virus (WNV) and St. Louis encephalitis (SLE) virus. One little brown bat and one northern long-eared bat tested positive for WNV neutralizing antibodies. No bats had antibodies to SLE virus. This was the first large-scale investigation of WNV infection in bats in New Jersey. Additional work is needed to determine the effects of WNV on bat populations.

Authors

Pilipski, Jacob D., Pilipski, Lucas M. and Risley, Lance S.

Year Published

2004

Publication

Journal of Wildlife Diseases

Locations
DOI

10.7589/0090-3558-40.2.335

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/15362837

West Nile Virus Antibodies in Avian Species of Georgia, USA: 2000–2004Gibbs, Samantha E.J.2006

West Nile Virus Antibodies in Avian Species of Georgia, USA: 2000–2004

Keywords

WNV

Abstract

West Nile virus (WNV) was first isolated in the state of Georgia in the summer of 2001. As amplifying hosts of WNV, avian species play an important role in the distribution and epidemiology of the virus. The objective of this study was to identify avian species that are locally involved as potential amplifying hosts of WNV and can serve as indicators of WNV transmission over the physiographic and land use variation present in the southeastern United States. Avian serum samples (n = 14,077) from 83 species of birds captured throughout Georgia during the summers of 2000–2004 were tested by a plaque reduction neutralization test for antibodies to WNV and St. Louis encephalitis virus. Over the 5-year period, WNV-neutralizing antibodies were detected in 869 (6.2%) samples. The WNV seroprevalence increased significantly throughout the study and was species dependent. The highest antibody prevalence rates were detected in rock pigeons (Columba livia), northern cardinals (Cardinalis cardinalis), common ground doves (Columbina passerina), grey catbirds (Deumetella carolinensis), and northern mockingbirds (Mimus polyglottos). Northern cardinals, in addition to having high geometric mean antibody titers and seroprevalence rates, were commonly found in all land use types and physiographic regions. Rock pigeons, common ground doves, grey catbirds, and northern mockingbirds, although also having high seroprevalence rates and high antibody titers against WNV, were more restricted in their distribution and therefore may be of more utility when attempting to assess exposure rates in specific habitat types. Of all species tested, northern cardinals represent the best potential avian indicator species for widespread serologic-based studies of WNV throughout Georgia due to their extensive range, ease of capture, and high antibody rates and titers. Due to the large geographic area covered by this species, their utility as a WNV sentinel species may include most of the eastern United States.

Authors

Stallknecht, David E., Gibbs, Samantha E.J., Yabsley, Michael J., Allison, Andrew B., Mead, Daniel G. and Wilcox, Benjamin R.

Year Published

2006

Publication

Vector-Borne and Zoonotic Diseases

Locations
DOI

10.1089/vbz.2006.6.57

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/16584328

West Nile virus and sage-grouse: What more have we learned?Naugle, DE2005

West Nile virus and sage-grouse: What more have we learned?

Keywords

Centrocercus urophasianus; emerging infectious disease; monitoring; population decline; sage-grouse; survival; West Nile virus

Abstract

West Nile virus (WNv) has emerged as a new issue in the conservation of native avifauna in North America. Mortality associated with WNv infection decreased survival of female greater sage-grouse (Centrocercus urophasianus) by 25% across 4 populations in Wyoming and Montana, USA, and Alberta, Canada, in 2003. In 2004 WNv spread to populations in Colorado and California, and female survival in late summer was 10% lower at 4 sites with confirmed WNv mortalities (86% survival) than at 8 sites without (96%). We still have no evidence that sage-grouse show resistance to the virus. The 2004 WNv season was not the catastrophe that many had predicted, and the decrease in prevalence of infection and mortality in sage-grouse, humans, and horses (except in California) has left many wondering if the worst has past. Evidence suggests that risk of infection was low in 2004 because unseasonably cool summer temperatures delayed or reduced mosquito production. Moreover, mortalities occurred 2-3 weeks later in 2004 than in 2003, and the shift to later timing was consistent between years at sites where WNv reduced survival both years. Mosquito surveillance data indicated a sharp decline in prevalence and infection rate of adult C. tarsalis in southeast Alberta, the most northern latitude where WNv reduced survival, in 2003 but not in 2004. A full understanding of the implications of WNv for sage-grouse requires a long-term, coordinated monitoring strategy among researchers and a sensitivity analysis to evaluate the role of WNv in population viability. Epidemiological research examining the prevalence and ecology of the virus among reservoir hosts is crucial.

Authors

Naugle, DE; Aldridge, CL; Walker, BL; Doherty, KE; Matchett, MR; McIntosh, J; Cornish, TE; Boyce, MS

Year Published

2005

Publication

Wildlife Society Bulletin

Locations
DOI

10.2193/0091-7648(2005)33[616:WNVASW]2.0.CO;2

West Nile Virus and Greater Sage-Grouse: Estimating Infection Rate in a Wild Bird PopulationWalker, Brett L.2007

West Nile Virus and Greater Sage-Grouse: Estimating Infection Rate in a Wild Bird Population

Keywords

Centrocercus urophasianus, coal-bed natural gas, energy development, flavivirus, greater sage-grouse, infection rate, sagebrush-steppe, West Nile virus

Abstract

Understanding impacts of disease on wild bird populations requires knowing not only mortality rate following infection, but also the proportion of the population that is infected. Greater sage-grouse (Centrocercus urophasianus) in western North America are known to have a high mortality rate following infection with West Nile virus (WNv), but actual infection rates in wild populations remain unknown. We used rates of WNv-related mortality and seroprevalence from radiomarked females to estimate infection rates in a wild greater sage-grouse population in the Powder River basin (PRB) of Montana and Wyoming from 2003 to 2005. Minimum WNv-related mortality rates ranged from 2.4% to 13.3% among years and maximum possible rates ranged from 8.2% to 28.9%. All live-captured birds in 2003 and 2004 tested seronegative. In spring 2005 and spring 2006, 10.3% and 1.8% respectively, of newly captured females tested seropositive for neutralizing antibodies to WNv. These are the first documented cases of sage-grouse surviving infection with WNv. Low to moderate WNv-related mortality in summer followed by low seroprevalence the following spring in all years indicates that annual infection rates were between 4% and 29%. This suggests that most sage-grouse in the PRB have not yet been exposed and remain susceptible. Impacts of WNv in the PRB in the near future will likely depend more on annual variation in temperature and changes in vector distribution than on the spread of resistance. Until the epizootiology of WNv in sagebrush-steppe ecosystems is better understood, we suggest that management to reduce impacts of WNv focus on eliminating man-made water sources that support breeding mosquitoes known to vector the virus. Our findings also underscore problems with using seroprevalence as a surrogate for infection rate and for identifying competent hosts in highly susceptible species.

Authors

Walker, Brett L.; Naugle, David E.; Doherty, Kevin E.; Cornish, Todd E.

Year Published

2007

Publication

Avian Diseases

Locations
DOI

10.1637/0005-2086(2007)51[691:WNVAGS]2.0.CO;2

Weather Variability Affects Abundance of Larval Culex (Diptera: Culicidae) in Storm Water Catch Basins in Suburban ChicagoGardner, Allison M.2012

Weather Variability Affects Abundance of Larval Culex (Diptera: Culicidae) in Storm Water Catch Basins in Suburban Chicago

Keywords

WNV

Abstract

Culex pipiens L. (Diptera: Culicidae) and Culex restuans Theobald are the primary enzootic and bridge vectors of West Nile virus in the eastern United States north of 36° latitude. Recent studies of the natural history of these species have implicated catch basins and underground storm drain systems as important larval development sites in urban and suburban locales. Although the presence of larvae in these habitats is well-documented, the influence of abiotic factors on the ecology of Culex larvae developing in them remains poorly understood. Therefore, we examined the effects of multiple abiotic factors and their interactions on abundance of Culex larvae in catch basins in the Chicago, IL, metropolitan area. Low precipitation and high mean daily temperature were associated with high larval abundance, whereas there was no correlation between catch basin depth or water depth and larval abundance. Rainfall was an especially strong predictor of presence or absence of larvae in the summer of 2010, a season with an unusually high precipitation. Regression tree methods were used to build a schematic decision tree model of the interactions among these factors. This practical, visual representation of key predictors of high larval production may be used by local mosquito abatement districts to target limited resources to treat catch basins when they are particularly likely to produce West Nile virus vectors.

Authors

Gardner, Allison M., Hamer, Gabriel L., Hines, Alicia M., Newman, Christina M., Walker, Edward D. and Ruiz, Marilyn O.

Year Published

2012

Publication

Journal of Medical Entomology

Locations
DOI

10.1603/ME11073

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/22493843

Weather and Land Cover Influences on Mosquito Populations in Sioux Falls, South DakotaChuang, Ting-Wu2011

Weather and Land Cover Influences on Mosquito Populations in Sioux Falls, South Dakota

Keywords

West Nile virus, Culex tarsalis, Aedes vexans, weather, land cover, WNV

Abstract

This study compared the spatial and temporal patterns of Culex tarsalis Coquillett and Aedes vexans Meigen populations and examined their relationships with land cover types and climatic variability in Sioux Falls, SD. Between 24 and 30 CDC CO2-baited light traps were set annually in Sioux Falls from May to September 2005–2008. Land cover data were acquired from the 2001 National Land Cover Dataset and the percentages of selected land cover types were calculated within a 600-m buffer zone around each trap. Meteorological information was summarized from local weather stations. Cx. tarsalis exhibited stronger spatial autocorrelation than Ae. vexans. Land cover analysis indicated that Cx. tarsalis was positively correlated with grass/hay, and Ae. vexans was positively correlated with wetlands. No associations were identified between irrigation and the host-seeking population of each species. Higher temperature in the current week and 2 wk prior and higher precipitation 3–4 wk before collection of host-seeking adult mosquitoes had positive influences on Cx. tarsalis abundance. Temperature in the current week and rainfall 2–3 wk before sampling had positive influences on Ae. vexans abundance. This study revealed the different influences of weather and land cover on important mosquito species in the Northern Great Plains region, which can be used to improve local vector control strategies and West Nile virus prevention efforts.

Authors

Chuang, Ting-Wu, Hildreth, Michael B., Vanroekel, Denise L. and Wimberly, Michael C.

Year Published

2011

Publication

Journal of Medical Entomology

Locations
DOI

10.1603/ME10246

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/21661329

Vector Surveillance for West Nile VirusWHITE, DENNIS J.2001

Vector Surveillance for West Nile Virus

Keywords

WNV

Abstract

West Nile virus (WNV) was detected in the metropolitan New York City (NYC) area during the summer and fall of 1999. Sixty-two human cases, including seven fatalities, were documented. The New York State Department of Health (NYSDOH) initiated and implemented a statewide mosquito and WNV surveillance system. We developed a WNV response plan designed to provide local health departments (LHD) a standardized means to begin to assess basic mosquito population data and to detect WNV circulation in mosquito populations. During the 2000 arbovirus surveillance season, local health agencies collected 317,676 mosquitoes and submitted 9,952 pools for virus testing. NYSDOH polymerase chain reaction (PCR) testing detected 363 WNV-positive pools. Eight species of mosquitoes were found to be infected. Of the 26 counties conducting mosquito surveillance, WNV-positive mosquitoes were detected only in NYC, on Long Island, and in four counties in the lower Hudson River valley region. LHD larval surveillance provided initial or enhanced mosquito habitat location and characterization and mosquito species documentation. Adult mosquito surveillance provided LHD information on species' presence, density, seasonal fluctuations, virus infection, minimum infection ratios (MIR) and indirect data on mosquito control efficacy after larval or adult control interventions. Collective surveillance activities conducted during 1999 and 2000 suggest that WNV has dispersed throughout the state and may affect local health jurisdictions within NYS, adjacent states, and Canada in future years. Vector surveillance will remain a critical component of LHD programs addressing public health concerns related to WNV.

Authors

WHITE, DENNIS J.

Year Published

2001

Publication

Annals of the New York Academy of Sciences

Locations
DOI

10.1111/j.1749-6632.2001.tb02686.x

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/11797806

Using Hydrologic Conditions to Forecast the Risk of Focal and Epidemic Arboviral Transmission in Peninsular FloridaDay, Jonathan F.2008

Using Hydrologic Conditions to Forecast the Risk of Focal and Epidemic Arboviral Transmission in Peninsular Florida

Keywords

arboviral epidemics, water table depth, hydrologic monitoring, St. Louis encephalitis virus, West Nile virus, WNV

Abstract

The accurate forecasting and tracking of arboviral transmission is becoming increasingly critical for the early recognition and management of arboviral epidemics. Meteorological factors, especially rainfall and temperature, drive arboviral epidemics, but monitoring rainfall and temperature alone is not predictive of increased levels of vector-borne disease transmission. In Florida, model simulations of water table depth (WTD) provide a measure of drought, and they have been shown to provide an accurate forecast of arboviral transmission. Here, we tracked WTD in two peninsular Florida regions where focal West Nile virus (family Flaviviridae, genus Flavivirus, WNV) transmission was reported during 2004 and 2005. We compared the resulting WTD profiles with historical WTD simulations for Indian River County (IRC), FL, where two peninsular Florida St. Louis encephalitis virus epidemics had their epicenters in 1977 and 1990. In both of the regions where focal WNV transmission was reported during 2004 and 2005, the local WTD profiles approached the 1977 and 1990 IRC WTD profiles; however, differences in the local temporal sequence of hydrologic conditions were observed. These differences seem in part to explain why the focal WNV transmission during 2004 and 2005 failed to reach epidemic levels in peninsular Florida. These findings suggest that hydrologic monitoring, specifically WTD, may help determine the geographic extent, timing, and intensity of WNV transmission. We speculate that a more precise sequence of drought and wetting, including a secondary summer drying and wetting cycle, as occurred in IRC during 1977 and 1990, may provide the optimal hydrologic conditions for the expansion of an arbovirus outbreak from focal to epidemic. This study documents that monitoring hydrologic conditions, along with vector, avian amplification host, and virus population data, increases our ability to track and predict significant levels of arboviral transmission.

Authors

Day, Jonathan F. and Shaman, Jeffrey

Year Published

2008

Publication

Journal of Medical Entomology

Locations
DOI

10.1603/0022-2585(2008)45[458:UHCTFT]2.0.CO;2

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18533440

Using a neural network for mining interpretable relationships of West Nile risk factorsGhosh, Debarchana2011

Using a neural network for mining interpretable relationships of West Nile risk factors

Keywords

West Nile virus; Risk factors; Nonlinear; Neural network; Urban morphology; USA, WNV

Abstract

The West Nile Virus (WNV) is an infectious disease spreading rapidly throughout the United States, causing illness among thousands of birds, animals, and humans. Yet, we only have a rudimentary understanding of how the mosquito-borne virus operates in complex avian–human environmental systems. The four broad categories of risk factors underlying WNV incidences are: environmental (temperature, precipitation, wetlands), socioeconomic (housing age), built-environment (catch basins, ditches), and existing mosquito abatement policies. This research first built a model incorporating the non-linear relationship between WNV incidences and hypothesized risk factors and second, identified important factor(s) whose management would result in effective disease prevention and containment. The research was conducted in the Metropolitan area of Minnesota, which had experienced significant WNV outbreaks from 2002. Computational neural network (CNN) modeling was used to understand the occurrence of WNV infected dead birds because of their ability to capture complex relationships with higher accuracy than linear models. Further a detailed interpretation technique, based on weights and biases of the network, provided a means for extracting relationships between risk factors and disease occurrence. Five risk factors: proximity to bogs, lakes, temperature, housing age, and developed medium density land cover class, were selected by the model. The detailed interpretation indicated that temperature, age of houses, and developed medium density land cover were positively related, and distance to bogs and lakes were negatively related to the incidence of WNV. This paper provides both applied and methodological contributions to the field of health geography. The relationships between the risk factors and disease occurrence could contribute to vector control strategies such as targeted insecticide spraying near bogs and lakes, mosquito control treatments for older houses, and extensive mapping, inspection, and treatments of catch basins. The proposed interpretation technique expanded the role of CNN models in health sciences as both predictive and explanatory tools.

Authors

Ghosh, Debarchana and Guha, Rajarshi

Year Published

2011

Publication

Social Science & Medicine

Locations
DOI

10.1016/j.socscimed.2010.09.014

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/20950908

Recent Articles

Effects of Temperature on Emergence and Seasonality of West Nile Virus in California

by Hartley, D. M., Barker, C. M., Le Menach, A., Niu, T., Gaff, H. D. and Reisen, W. K.

Temperature has played a critical role in the spatiotemporal dynamics of West Nile virus transmission throughout California from its introduction in 2003 through establishment by 2009. We compared two novel mechanistic measures of transmission risk, the temperature-dependent ratio of virus extrinsic incubation period to the mosquito gonotrophic period (BT), and the fundamental reproductive rati...

published 2012 in American Journal of Tropical Medicine and Hygiene

Weather Variability Affects Abundance of Larval culex (diptera: Culicidae) in Storm Water Catch Basins in Suburban Chicago

by Gardner, Allison M., Hamer, Gabriel L., Hines, Alicia M., Newman, Christina M., Walker, Edward D. and Ruiz, Marilyn O.

Culex pipiens L. (Diptera: Culicidae) and Culex restuans Theobald are the primary enzootic and bridge vectors of West Nile virus in the eastern United States north of 36° latitude. Recent studies of the natural history of these species have implicated catch basins and underground storm drain systems as important larval development sites in urban and suburban locales. Although the presence of la...

published 2012 in Journal of Medical Entomology


Wild Birds as Sentinels for Multiple Zoonotic Pathogens Along an Urban to Rural Gradient in Greater Chicago, Illinois

by Hamer, S. A., Lehrer, E. and Magle, S. B.

Wild birds are important in the maintenance and transmission of many zoonotic pathogens. With increasing urbanization and the resulting emergence of zoonotic diseases, it is critical to understand the relationships among birds, vectors, zoonotic pathogens, and the urban landscape. Here, we use wild birds as sentinels across a gradient of urbanization to understand the relative risk of diseases ...

published 2012 in Zoonoses and Public Health

Completeness of West Nile Virus Testing in Patients with Meningitis and Encephalitis During an Outbreak in Arizona, Usa

by WEBER, I. B., LINDSEY, N. P., BUNKO-PATTERSON, A. M., BRIGGS, G., WADLEIGH, T. J., SYLVESTER, T. L., LEVY, C., KOMATSU, K. K., LEHMAN, J. A., FISCHER, M. and STAPLES, J. E.

Accurate data on West Nile virus (WNV) cases help guide public health education and control activities, and impact regional WNV blood product screening procedures. During an outbreak of WNV disease in Arizona, records from patients with meningitis or encephalitis were reviewed to determine the proportion tested for WNV. Of 60 patients identified with meningitis or encephalitis, 24 (40%) were te...

published 2012 in Epidemiology and Infection