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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
Field Comparison of Novel and Gold Standard Traps for Collecting Aedes albopictus in Northern VirginiaMeeraus, Wilhelmine H.2008

Field Comparison of Novel and Gold Standard Traps for Collecting Aedes albopictus in Northern Virginia

Keywords

Centers for Disease Control and Prevention miniature light trap, BG-SentinelTM, CMT-20TM (ZumbaTM), Aedes albopictus, adult mosquito surveillance, WNV

Abstract

Aedes albopictus is a potential West Nile virus bridge vector in Northern Virginia; however, information regarding its virus transmission dynamics is limited, as this species is not readily collected in existing traps. This study used 5 replicates of a 5 × 5 Latin square to evaluate the efficiency and effectiveness of 2 novel host-seeking mosquito traps (the BG-SentinelTM and the Collapsible Mosquito Trap (CMT-20TM) in collecting Ae. albopictus, relative to a carbon dioxide (CO2)–baited Centers for Disease Control and Prevention (CDC) miniature light trap. When used with CO2, the BG-Sentinel (with BG-Lure) collected 33 times more female Ae. albopictus per 24-h trapping period than did the CO2-baited CDC light trap. Without CO2, the BG-Sentinel (with BG-Lure) still collected over 6 times as many female Ae. albopictus as the CO2-baited CDC trap. Both configurations of the BG-Sentinel were significantly more effective than the other traps. The BG-Sentinel was also significantly more efficient in collecting Ae. albopictus and collected a high proportion of this species, both with CO2 and without CO2. The CMT-20 (with SkinLureTM) collected significantly more Ae. albopictus when used with CO2 than without CO2, but did not collect significantly more Ae. albopictus than the CO2-baited CDC light trap. The proportion of Ae. albopictus collected in the CMT-20 with CO2 and without CO2 did not differ significantly from the proportion of Ae. albopictus collected in the CDC trap.

Authors

Meeraus, Wilhelmine H., Armistead, Jennifer S. and Arias, Jorge R.

Year Published

2008

Publication

Journal of the American Mosquito Control Association

Locations
DOI

10.2987/5676.1

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18666532

Juvenile Dogs as Potential Sentinels for West Nile Virus SurveillanceResnick, M. P.2008

Juvenile Dogs as Potential Sentinels for West Nile Virus Surveillance

Keywords

West Nile virus;surveillance;canines;seroconversion;sentinels;enzyme-linked immunosorbant assay, WNV

Abstract

We conducted a study to determine whether juvenile stray dogs could be sentinels for West Nile virus (WNV) surveillance. Seroconversion was detected 6 weeks before the first reported human case. Our findings provide evidence that dogs could be useful sentinels for monitoring areas for evidence of WNV during transmission seasons.

Authors

Resnick, M. P., Grunenwald, P., Blackmar, D., Hailey, C., Bueno, R. and Murray, K. O.

Year Published

2008

Publication

Zoonoses and Public Health

Locations
DOI

10.1111/j.1863-2378.2008.01116.x

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18399945

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

Landscape, demographic, entomological, and climatic associations with human disease incidence of West Nile virus in the state of Iowa, USADeGroote, John P2008

Landscape, demographic, entomological, and climatic associations with human disease incidence of West Nile virus in the state of Iowa, USA

Keywords

WNV

Abstract

Background West Nile virus (WNV) emerged as a threat to public and veterinary health in the Midwest United States in 2001 and continues to cause significant morbidity and mortality annually. To investigate biotic and abiotic factors associated with disease incidence, cases of reported human disease caused by West Nile virus (WNV) in the state of Iowa were aggregated by census block groups in Iowa for the years 2002–2006. Spatially explicit data on landscape, demographic, and climatic conditions were collated and analyzed by census block groups. Statistical tests of differences between means and distributions of landscape, demographic, and climatic variables for census block groups with and without WNV disease incidence were carried out. Entomological data from Iowa were considered at the state level to add context to the potential ecological events taking place. Results Numerous statistically significant differences were shown in the means and distributions of various landscape and demographic variables for census block groups with and without WNV disease incidence. Census block groups with WNV disease incidence had significantly lower population densities than those without. Landscape variables showing differences included stream density, road density, land cover compositions, presence of irrigation, and presence of animal feeding operations. Statistically significant differences in the annual means of precipitations, dew point, and minimum temperature for both the year of WNV disease incidence and the prior year, were detected in at least one year of the analysis for each parameter. However, the differences were not consistent between years. Conclusion The analysis of human WNV disease incidence by census block groups in Iowa demonstrated unique landscape, demographic, and climatic associations. Our results indicate that multiple ecological WNV transmission dynamics are most likely taking place in Iowa. In 2003 and 2006, drier conditions were associated with WNV disease incidence. In a significant novel finding, rural agricultural settings were shown to be strongly associated with human WNV disease incidence in Iowa.

Authors

DeGroote, John P, Sugumaran, Ramanathan, Brend, Sarah M, Tucker, Brad J and Bartholomay, Lyric C

Year Published

2008

Publication

International Journal of Health Geographics

Locations
DOI

10.1186/1476-072X-7-19

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18452604

Mosquito Species Richness, Composition, and Abundance along Habitat-Climate-Elevation Gradients in the Northern Colorado Front RangeEisen, Lars2008

Mosquito Species Richness, Composition, and Abundance along Habitat-Climate-Elevation Gradients in the Northern Colorado Front Range

Keywords

Aedes, Culex, Culiseta, Ochlerotatus, climate, WNV

Abstract

We exploited elevation gradients (1,500–2,400 m) ranging from plains to montane areas along the Poudre River and Big Thompson River in the northern Colorado Front Range to determine how mosquito species richness, composition, and abundance change along natural habitat-climate-elevation gradients. Mosquito collections in 26 sites in 2006 by using CO2-baited CDC light traps yielded a total of 7,136 identifiable mosquitoes of 27 species. Commonly collected species included Aedes vexans (Meigen) (n = 4,722), Culex tarsalis Coquillett (n = 825), Ochlerotatus increpitus (Dyar) (n = 546), Ochlerotatus trivittatus (Coquillett) (n = 303), Aedes cinereus Meigen (n = 280), Ochlerotatus melanimon (Dyar) (n = 146), Ochlerotatus dorsalis (Meigen) (n = 67), Culiseta inornata (Williston) (n = 52), Ochlerotatus pullatus (Coquillett) (n = 38), Ochlerotatus spencerii idahoensis (Theobald) (n = 37), and Culex pipiens L. (n = 29). Species richness was highest in plains habitats at elevations below 1,600 m. Numerous species were found exclusively or predominantly at low elevations below 1,700 m [Anopheles earlei Vargas, Anopheles freeborni Aitken, Coquilletidia perturbans (Walker), Culex erythrothorax (Dyar), Cx. pipiens, Culex territans Walker, Oc. dorsalis, Ochlerotatus hendersoni (Cockerell), Oc. melanimon, and Oc. trivittatus], whereas others occurred predominantly at high elevations above 2,300 m [Ae. cinereus, Culiseta incidens (Thomson), Culiseta morsitans (Theoblad), Ochlerotatus cataphylla (Dyar), Ochlerotatus intrudens (Dyar), Oc. pullatus, and Ochlerotatus punctor (Kirby)]. Ae. vexans and Cx. tarsalis were abundant in the plains (19.5°C), occurred at low abundances in foothills and low montane areas (1,610–1,730 m; 18.0–19.5°C), and they were collected only sporadically in montane areas above 1,750 m (mean June–August temperature <17.5°C). These findings suggest that future climate warming may lead to shifts in distribution patterns of West Nile virus vectors (e.g., Cx. tarsalis) toward higher elevations in Colorado.

Authors

Eisen, Lars, Bolling, Bethany G., Blair, Caroll D., Beaty, Barry J. and Moore, Chester G.

Year Published

2008

Publication

Journal of Medical Entomology

Locations
DOI

10.1603/0022-2585(2008)45[800:MSRCAA]2.0.CO;2

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18714885

Urban Wet Environment as Mosquito Habitat in the Upper MidwestIrwin, Patrick2008

Urban Wet Environment as Mosquito Habitat in the Upper Midwest

Keywords

WNV

Abstract

Sampling of Culex larval habitat plays an important role in West Nile virus surveillance and control programs. Although many cities have established mosquito sampling programs and abatement districts, there is relatively little information describing the extent and ecology of urban surface waters and stormwater systems in different geographic areas and how these parameters affect mosquito communities and control strategies. An aerial survey of the city of Madison, Wisconsin revealed 521 above-ground wet sites. These included both constructed stormwater systems (ditches, retention ponds, detention ponds) and natural wetlands (marshes, flood areas, creeks, and rivers). Repeat sampling of 351 of these sites was conducted during 2004 and 2005. The majority of sites, 58% in 2004 and 72% in 2005, yielded no mosquito larvae, suggesting that physical and biological features of these wet sites limit the development of mosquito larvae. For both years, analysis of the positive samples revealed that less than 25% of sites produced Culex spp. while a small number of ditches and detention ponds were consistent “superproducers” of Culex larvae from year to year. This information will facilitate comparisons across geographical areas and provides insight into local variation in the public health risk due to mosquito transmission of human disease agents.

Authors

Irwin, Patrick, Arcari, Christine, Hausbeck, John and Paskewitz, Susan

Year Published

2008

Publication

EcoHealth

Locations
DOI

10.1007/s10393-007-0152-y

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18648797

Remotely-Sensed Vegetation Indices Identify Mosquito Clusters of West Nile Virus Vectors in an Urban Landscape in the Northeastern United StatesBrown, Heidi2008

Remotely-Sensed Vegetation Indices Identify Mosquito Clusters of West Nile Virus Vectors in an Urban Landscape in the Northeastern United States

Keywords

WNV

Abstract

Heterogeneity in urban landscapes can influence the effectiveness of mosquito-borne disease control. We used remotely sensed vegetation indices to discriminate among mosquito habitats within a densely populated urban environment in New Haven, CT. ASTER derived vegetation indices were identified for 16 sites where adult mosquitoes were trapped over the summer of 2004. Canonical correlation analysis showed a significant relationship between the environmental variables (normalized difference vegetation index, disease/water stress index and distance to water) and four local West Nile virus competent vectors (Cx. pipiens, Cx. restuans, Cx. salinarius, and Ae. vexans) (0.93, P = 0.03) explaining 86% of the variance in the environmental and mosquito measures. Sites were clustered based on these remotely sensed environmental variables. Three clusters were identified which provide insight into the distribution of West Nile virus vectors in an urban area. Identification of habitat differences of mosquitoes within the urban landscape has important implications for understanding West Nile virus transmission and for control of vector-competent mosquito species.

Authors

Fish, Durland, Brown, Heidi, Diuk-Wasser, Maria and Andreadis, Theodore

Year Published

2008

Publication

Vector-Borne and Zoonotic Diseases

Locations
DOI

10.1089/vbz.2007.0154

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18452400

Predictable ecology and geography of West Nile virus transmission in the central United StatesPeterson, A. Townsend2008

Predictable ecology and geography of West Nile virus transmission in the central United States

Keywords

West Nile virus, ecological niche modeling, prediction, forecasting, WNV

Abstract

West Nile virus (WNV) arrived in North America and spread rapidly through the western hemisphere. We present a series of tests to determine whether ecological factors are consistently associated with WNV transmission to humans. We analyzed human WNV cases in the states of Illinois, Indiana, and Ohio in 2002 and 2003, building ecological niche models to associate WNV case occurrences with ecological and environmental parameters. In essentially all tests, both within states, among states, between years, and across the region, we found high predictivity of WNV case distributions, suggesting that one or more elements in the WNV transmission cycle has a strong ecological determination. Areas in the geographic region included in this study predicted as suitable for WNV transmission tended to have lower values of the vegetation indices in the summer months, pointing to consistent ecological differences between suitable and unsuitable areas.

Authors

Nasci, Roger, Peterson, A. Townsend, Robbins, Amber, Restifo, Robert and Howell, James

Year Published

2008

Publication

Journal of Vector Ecology

Locations
DOI

10.3376/1081-1710-33.2.342

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/19263855

Rapid Amplification of West Nile Virus: The Role of Hatch-Year BirdsHamer, Gabriel L.2008

Rapid Amplification of West Nile Virus: The Role of Hatch-Year Birds

Keywords

WNV

Abstract

Epizootic transmission of West Nile virus (WNV) often intensifies rapidly leading to increasing risk of human infection, but the processes underlying amplification remain poorly understood. We quantified epizootic WNV transmission in communities of mosquitoes and birds in the Chicago, Illinois (USA) region during 2005 and 2006. Using quantitative polymerase chain reaction (PCR) methods, we detected WNV in 227 of 1195 mosquito pools (19%) in 2005 and 205 of 1685 (12%) in 2006; nearly all were Culex pipiens. In both years, mosquito infection rates increased rapidly in the second half of July to a peak of 59/1000 mosquitoes in 2005 and 33/1000 in 2006, and then declined slowly. Viral RNA was detected in 11 of 998 bird sera (1.1%) in 2005 and 3 of 1285 bird sera (<1%) in 2006; 11 of the 14 virus-positive birds were hatch-year birds. Of 540 hatch-year birds, 100 (18.5%) were seropositive in 2005, but only 2.8% (14/493) tested seropositive in 2006 for WNV antibodies using inhibition enzyme-linked immunosorbent assay (ELISA). We observed significant time series cross-correlations between mosquito infection rate and proportion of virus-positive birds, proportion of hatch-year birds captured in mist nets (significant in 2006 only), seroprevalence of hatch-year birds, and number of human cases in both seasons. These associations, coupled with the predominance of WNV infection and seropositivity in hatch-year birds, indicate a key role for hatch-year birds in the amplification of epizootic transmission of WNV, and in increasing human infection risk by facilitating local viral amplification.

Authors

Hamer, Gabriel L., Walker, Edward D., Brawn, Jeffrey D., Loss, Scott R., Ruiz, Marilyn O., Goldberg, Tony L., Schotthoefer, Anna M., Brown, William M., Wheeler, Emily and Kitron, Uriel D.

Year Published

2008

Publication

Vector-Borne and Zoonotic Diseases

Locations
DOI

10.1089/vbz.2007.0123

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18237262

Naturally Induced Humoral Immunity to West Nile Virus Infection in RaptorsNemeth, Nicole M.2008

Naturally Induced Humoral Immunity to West Nile Virus Infection in Raptors

Keywords

WNV

Abstract

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

Authors

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

Year Published

2008

Publication

EcoHealth

Locations
DOI

10.1007/s10393-008-0183-z

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18677535

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