| Year-round West Nile Virus Activity, Gulf Coast Region, Texas and Louisiana | Tesh, Robert B. | 2004 |
KeywordsWNV AbstractWest Nile virus (WNV) was detected in 11 dead birds and two mosquito pools collected in east Texas and southern Louisiana during surveillance studies in the winter of 2003 to 2004. These findings suggest that WNV is active throughout the year in this region of the United States. AuthorsTesh, Robert B., Parsons, Ray, Siirin, Marina, Randle, Yvonne, Sargent, Chris, Guzman, Hilda, Wuithiranyagool, Taweesak, Higgs, Stephen, Vanlandingham, Dana L., Bala, Adil A., Haas, Keith and Zerinque, Brian Year Published2004 PublicationEmerging Infectious Diseases LocationsDOI10.3201/eid1009.040203 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/15498169 |
| Wintering of Neurotropic Velogenic Newcastle Disease Virus and West Nile Virus in Double-Crested Cormorants (Phalacrocorax auritus) from the Florida Keys | Allison, A. B. | 2005 |
KeywordsNewcastle disease virus, double-crested cormorant, fusion protein, West Nile virus, Florida, wintering grounds, reservoir, WNV AbstractDuring November 2002, six double-crested cormorants (DCCs; Phalacrocorax auritus) were found moribund in Big Pine Key, FL, exhibiting clinical signs indicative of neurologic disease. Postmortem diagnostic evaluations were performed on two adult birds. Virulent Newcastle disease virus (NDV) was isolated from a cloacal swab from cormorant 1. West Nile virus (WNV) was isolated from the brain and lung of cormorant 2. Nucleotide sequence analysis of a portion of the fusion (F) protein gene of the NDV cormorant isolate revealed it shared a 100% deduced amino acid identity with only two viruses: the 1992 epizootic cormorant isolate from Minnesota and the 1992 turkey isolate from North Dakota. The epidemiologic significance of the recognition of virulent NDV on cormorant wintering grounds during a nonepizootic period, in addition to the potential implications of the concurrent isolation of NDV and WNV from cormorants, is discussed. AuthorsAllison, A. B., Gottdenker, N. L. and Stallknecht, D. E. Year Published2005 PublicationAvian Diseases LocationsDOI10.1637/7278-091304R Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/16094838 |
| Winter Biology of Wetland Mosquitoes at a Focus of Eastern Equine Encephalomyelitis Virus Transmission in Alabama, USA | Burkett-Cadena, Nathan D. | 2011 |
Keywordsoverwintering, mosquito, winter emergence, eastern equine encephalitis, WNV AbstractAt temperate latitudes, vectors and pathogens must possess biological mechanisms for coping with cold temperatures and surviving from one transmission season to the next. Mosquitoes that overwinter in the adult stage have been proposed as winter maintenance hosts for certain arboviruses. In the cases of West Nile virus (family Flaviviridae, genus Flavivirus) and St. Louis encephalitis virus (family Flaviviridae, genus Flavivirus), discovery of infected overwintering females lends support to this hypothesis, but for other arboviruses, in particular Eastern equine encephalomyelitis virus (family Togaviridae, genus Alphavirus, EEEV), overwintering of the virus in mosquito hosts as not been demonstrated. In the current study, we collected overwintering mosquitoes from a focus of EEEV transmission in the southeastern United States to determine whether mosquitoes serve as winter maintenance hosts for EEEV and to document overwintering biologies of suspected vectors. No virus was detected via reverse transcription-polymerase chain reaction of >500 female mosquitoes collected during three winters. Investigation into the winter biologies indicated that Anopheles punctipennis (Say), Culex erraticus (Dyar & Knab), Culex peccator Dyar & Knab, and Uranotaenia sapphirina (Osten Sacken) overwinter as females. Females of these species were collected from hollow trees and emergence traps placed over ground holes. Southern magnolia, Magnolia grandiflora L., trees were preferred overwintering sites of culicine mosquitoes. Emergence from underground overwintering sites peaked in mid-March, when air temperatures reached 18–22°C, and the first bloodengorged females of Cx. erraticus and Cx. peccator were collected during this same period. Blood-fed Culex territans Walker females were collected as early as mid-February. This work provides insight into the overwintering biologies of suspected virus vectors at a site of active EEEV transmission and provides limited evidence against the hypothesis that EEEV persists through intertransmission periods in overwintering mosquitoes. AuthorsBurkett-Cadena, Nathan D., White, Gregory S., Eubanks, Micky D. and UNNASCH, THOMAS R. Year Published2011 PublicationJournal of Medical Entomology LocationsDOI10.1603/ME10265 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/21936314 |
| Wild Birds as Sentinels for Multiple Zoonotic Pathogens Along an Urban to Rural Gradient in Greater Chicago, Illinois | Hamer, S. A. | 2012 |
Keywordswild birds, urbanization, Salmonella, Borrelia burgdorferi, West Nile virus, Zoonoses, WNV AbstractWild 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 caused by three types of zoonotic pathogens: Salmonella pathogens, mosquito-borne West Nile virus (WNV) and tick-borne pathogens, including the agents of Lyme disease and human anaplasmosis. Wild birds were captured using mist nets at five sites throughout greater Chicago, Illinois, and blood, faecal and ectoparasite samples were collected for diagnostic testing. A total of 289 birds were captured across all sites. A total of 2.8% of birds harboured Ixodes scapularis– the blacklegged tick – of which 54.5% were infected with the agent of Lyme disease, and none were infected with the agent of human anaplasmosis. All infested birds were from a single site that was relatively less urban. A single bird, captured at the only field site in which supplemental bird feeding was practised within the mist netting zone, was infected with Salmonella enterica subspecies enterica. While no birds harboured WNV in their blood, 3.5% of birds were seropositive, and birds from more urban sites had higher exposure to the virus than those from less urban sites. Our results demonstrate the presence of multiple bird-borne zoonotic pathogens across a gradient of urbanization and provide an assessment of potential public health risks to the high-density human populations within the area. AuthorsHamer, S. A., Lehrer, E. and Magle, S. B. Year Published2012 PublicationZoonoses and Public Health Locations- Des Plaines, Illinois (42.0334, -87.8834)
- Batavia, Illinois (41.85, -88.3126)
- Wheaton, Illinois (41.8661, -88.107)
- Maywood, Illinois (41.8792, -87.8431)
- Lemont, Illinois (41.6736, -88.0017)
DOI10.1111/j.1863-2378.2012.01462.x |
| WILD BIRD MORTALITY AND WEST NILE VIRUS SURVEILLANCE: BIASES ASSOCIATED WITH DETECTION, REPORTING, AND CARCASS PERSISTENCE | Ward, Marsha R. | 2006 |
KeywordsAmerican crow, carcass, house sparrow, persistence, scavenging, surveillance, West Nile virus, WNV AbstractSurveillance targeting dead wild birds, in particular American crows (Corvus brachyrhynchos), plays a critical role in West Nile virus (WNV) surveillance in the United States. Using crow decoy surrogates, detection and reporting of crow carcasses within urban and rural environments of DeKalb County, Georgia were assessed for potential biases that might occur in the county's WNV surveillance program. In each of two replicated trials, during July and September 2003, 400 decoys were labeled with reporting instructions and distributed along randomly chosen routes throughout designated urban and rural areas within DeKalb County. Information-theoretic methods were used to compare alternative models incorporating the effects of area and trial on probabilities of detection and reporting. The model with the best empirical support included the effects of area on both detection and reporting of decoys. The proportion of decoys detected in the urban area (0.605, SE=0.024) was approximately twice that of the rural area (0.293, SE=0.023), and the proportion of decoys reported in the urban area (0.273, SE=0.023) was approximately three times that of the rural area (0.103, SE=0.028). These results suggest that human density and associated factors can substantially influence dead crow detection and reporting and, thus, the perceived distribution of WNV. In a second and separate study, the persistence and fate of American crow and house sparrow (Passer domesticus) carcasses were assessed in urban and rural environments in Athens-Clarke, Madison, and Oconee counties, Georgia. Two replicated trials using 96 carcasses of each species were conducted during July and September 2004. For a portion of the carcasses, motion sensitive cameras were used to monitor scavenging species visits. Most carcasses (82%) disappeared or were decayed by the end of the 6-day study. Carcass persistence averaged 1.6 days in rural areas and 2.1 days in urban areas. We analyzed carcass persistence rates using a known-fate model framework in program MARK. Model selection based on Akaike's Information Criteria (AIC) indicated that the best model explaining carcass persistence rates included species and number of days of exposure; however, the model including area and number of days of exposure received approximately equal support. Model-averaged carcass persistence rates were higher for urban areas and for crow carcasses. Six mammalian and one avian species were documented scavenging upon carcasses. Dead wild birds could represent potential sources of oral WNV exposure to these scavenging species. Species composition of the scavenger assemblage was similar in urban and rural areas but “scavenging pressure” was greater in rural areas. AuthorsWard, Marsha R., Stallknecht, David E., Willis, Juanette, Conroy, Michael J. and Davidson, William R. Year Published2006 PublicationJournal of Wildlife Diseases LocationsDOI10.7589/0090-3558-42.1.92 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/16699152 |
| Wicking Assays for the Rapid Detection of West Nile and St. Louis Encephalitis Viral Antigens in Mosquitoes (Diptera: Culicidae) | Ryan, J. | 2003 |
Keywordsarbovirus, West Nile virus, St. Louis encephalitis, rapid detection, wicking assay, surveillance, WNV AbstractThe recent outbreaks of West Nile (WN) encephalitis and St. Louis encephalitis (SLE) in the United States have highlighted the need for rapid and specific methods of detecting arboviral antigens in mosquitoes. We evaluated rapid, field-usable assays for detecting and differentiating WN and SLE viruses in mosquito pools, based on a patent-pending, immunochromatographic technology (VecTest) formatted on a dipstick. The device provides results in less than 20 min and can be used in laboratories with adequate containment facilities. In laboratory assessments, both the SLE and WN virus tests demonstrated sensitivity comparable with that of an antigen capture ELISA, but less than can be achieved with Vero cell plaque or reverse-transcriptase polymerase chain reaction assays. There was no evidence of cross-reaction when tested with high concentrations of heterologous flavivirus antigens or with Eastern equine encephalitis or Western equine encephalitis viruses. Both the WN and SLE dipstick tests delivered a clear positive result with a single positive specimen in a pool of 50 mosquitoes. This virus assay technology reduces the time required to obtain test results and will allow rapid medical threat assessment and effective targeting of vector control measures. AuthorsRyan, J., Davé, K., Emmerich, É., Fernández, B., Turell, M., Johnson, J., Gottfried, K., Burkhalter, K., Kerst, A., Hunt, A., Wirtz, R. and Nasci, R. Year Published2003 PublicationJournal of Medical Entomology LocationsDOI10.1603/0022-2585-40.1.95 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/12597660 |
| West Nile virus: pending crisis for greater sage-grouse | Naugle, DE | 2004 |
KeywordsCentrocercus urophasianus, emerging infectious disease, endangered species; greater sage-grouse; mosquito; population decline; survival; vector surveillance; West Nile virus AbstractScientists have feared that emerging infectious diseases could complicate efforts to conserve rare and endangered species, but quantifying impacts has proven difficult until now. We report unexpected impacts of West Nile virus (WNv) on radio-marked greater sage-grouse (Centrocercus urophasianus), a species that has declined 45-80% and is endangered in Canada and under current consideration for federal listing in the US. We show that WNv reduced late-summer survival an average of 25% in four radio-marked populations in the western US and Canada. Serum from 112 sage-grouse collected after the outbreak show that none had antibodies, suggesting that they lack resistance. The spread of WNv represents a significant new stressor on sage-grouse and probably other at-risk species. While managing habitat might lessen its impact on sage-grouse populations, WNv has left wildlife and public health officials scrambling to address surface water and vector control issues in western North America. AuthorsNaugle, DE; Aldridge, CL; Walker, BL; Cornish, TE; Moynahan, BJ; Holloran, MJ; Brown, K; Johnson, GD; Schmidtmann, ET; Mayer, RT; Kato, CY; Matchett, MR; Christiansen, TJ; Cook, WE; Creekmore, T; Falise, RD; Rinkes, ET; Boyce, MS Year Published2004 PublicationEcology Letters LocationsDOI10.1111/j.1461-0248.2004.00631.x |
| West nile virus-associated optic neuritis and chorioretinitis | Anninger, William V. | 2003 |
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| West Nile Virus Surveillance: A Simple Method for Verifying the Integrity of RNA in Mosquito (Diptera: Culicidae) Pools | Hoffmann, Peter R. | 2004 |
KeywordsWest Nile virus, reverse transcriptase-polymerase chain reaction, mosquito, arbovirus, 18S rRNA, WNV AbstractIn a West Nile virus (WNV)-free ecosystem, it is essential to verify the integrity of RNA before concluding that RNA extracted from mosquito specimens is negative for WNV gene sequences. The primary objective of our study was to develop a rapid molecular assay to rapidly screen mosquitoes for the presence of 18S RNA and WNV gene sequences. Mosquitoes, collected from multiple sites on the island of O‘ahu, were pooled into groups of 1–50 mosquitoes according to capture site, date, and species. Using primer design software and the GenBank database, generic oligonucleotide primer pairs were designed to amplify mosquito18S rRNA gene sequences from different species. RNA was extracted from mosquito pools, and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed for the presence of mosquito18S rRNA and WNV gene sequences. Three of the seven primer pairs successfully detected 18S rRNA sequences for both Aedes and Culex by RT-PCR, and one primer pair successfully amplified 18S rRNA sequences for 15 different mosquito species. All 64 mosquito pools from 10 different sites on the island of Oahu, Hawaii, were negative for WNV nonstructural protein-5 gene sequences. This simple, one-step RT-PCR method for screening mosquito pools for arboviruses will become an increasingly valuable tool as WNV becomes endemic throughout the Americas. AuthorsHoffmann, Peter R., Woodrow, Robert J., Calimlim, Precilia S., Sciulli, Rebecca, Effler, Paul V., Miyamoto, Vernon, Imrie, Allison, Yanagihara, Richard and Nerurkar, Vivek R. Year Published2004 PublicationJournal of Medical Entomology LocationsDOI10.1603/0022-2585-41.4.731 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/15311468 |
| WEST NILE VIRUS SURVEILLANCE IN MOSQUITOES IN NEW YORK STATE, 2000–2004 | LUKACIK, GARY | 2006 |
KeywordsWest Nile virus, Culex, virus surveillance, gravid traps, WNV AbstractA West Nile virus (WNV) surveillance system was created and implemented in New York State (NYS) in 2000 and described previously (White et al. 2001). We examine and evaluate the results of mosquito and virus surveillance for 2000 through 2004 exclusive of New York City. Forty-nine counties submitted 1,095,426 mosquitoes in 35,280 pools for WNV assay. Specimens of 47 species were tested, with Culex species accounting for 47.6% of all pools tested. WNV was detected in 814 pools from 10 species, with combined Culex pipiens/Culex restuans pools accounting for 90.8% of all detections. Pools submitted from gravid traps were 5.7 times more likely to be positive than submissions from carbon dioxide-baited light traps. Most human WNV cases resided in counties that conducted mosquito surveillance. Local health departments' use of mosquito surveillance information often led to an enhanced disease prevention response. In NYS, Cx. pipiens/Cx. restuans group are the most likely vectors of WNV. Future efforts to improve system efficacy are discussed. AuthorsWHITE, DENNIS J., Kramer, Laura D., LUKACIK, GARY, ANAND, MADHU, SHUSAS, EMILY J., HOWARD, JOHN J., OLIVER, JOANNE, CHEN, HAIYAN, BACKENSON, P. BRYON, KAUFFMAN, ELIZABETH B. and BERNARD, KRISTEN A. Year Published2006 PublicationJournal of the American Mosquito Control Association LocationsDOI10.2987/8756-971X(2006)22[264:WNVSIM]2.0.CO;2 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/17019772 |
