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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
West Nile Virus from Female and Male Mosquitoes (Diptera: Culicidae) in Subterranean, Ground, and Canopy Habitats in ConnecticutAnderson, John F.2006

West Nile Virus from Female and Male Mosquitoes (Diptera: Culicidae) in Subterranean, Ground, and Canopy Habitats in Connecticut

Keywords

West Nile virus, Culex restuans, Culex salinarius, Aedes vexans, Culex pipiens, WNV

Abstract

In total, 93,532 female mosquitoes (Diptera: Culicidae) were captured in traps placed in subterranean (catch basin), ground (≈ 1.5 m above ground), and canopy (≈7.0 m above ground) habitats in Stamford and Stratford, CT, during 2003–2005. Culex pipiens L. was the most abundant (64.8%) of the 31 species identified. Significantly greater numbers of Cx. pipiens were captured in canopy-placed mosquito magnet experimental traps, and significantly greater numbers were collected in catch basin-placed (Centers for Disease Control) CDC traps than in CDC traps placed elsewhere. Culex restuans Theobald was captured in significantly greater numbers in traps placed in catch basins. Aedes vexans (Meigen), Aedes cinereus Meigen, and Aedes cantator (Coquillett) were significantly more abundant in ground traps. In total, 429 isolations of West Nile virus (WNV) were made from seven species of mosquitoes from late June through the end of October during 2003 through 2005. Three hundred ninety-eight (92.8%) isolates were from Cx. pipiens. Others were from Cx. restuans (n = 16), Culex salinarius Coquillett (n = 5), Ae. vexans (n = 4), Ae. cantator (n = 3), Aedes triseriatus (Say) (n = 2), and Ae. cinereus (n = 1). Multiple isolates from Cx. pipiens were made each week, primarily during the later part of July through the end of September. Weekly minimum infection rates (MIRs) were lower in 2004 (highest weekly MIR = 7.1) when no human cases were reported in Connecticut in comparison with 2003 and 2005 (highest weekly MIR = 83.9) when human cases were documented. Frequencies of infected pools were significantly higher in Cx. pipiens captured in traps in the canopy and significantly higher in catch basin placed traps than in traps at ground level. The physiological age structure of Cx. pipiens captured in the canopy was significantly different from that of Cx. pipiens collected in catch basins. Invariably, Cx. pipiens captured in the canopy were nulliparous or parous with ovaries in Christophers’ stage 2, whereas 58.7% of the females captured in catch basins possessed ovaries filled with mature oocytes in Christophers’ stage 5. Our results suggest that females in the canopy are seeking hosts, and after digestion of the bloodmeal and development of mature oocytes, they descend to catch basins for shelter and deposition of eggs. WNV was isolated from three, one, and two pools of male Cx. pipiens captured in catch basin-, ground-, and canopy-placed traps, respectively, and from six nulliparous Cx. pipiens females collected in the canopy. Weekly MIR ranged from 1.2 to 31.1 per 1,000 male specimens. These data show that mosquitoes become infected by means other than by blood feeding, possibly by transovarial transmission. The placement of traps in tree canopies and in catch basins can be used to augment current practices of placement of traps near the ground for surveillance of mosquitoes infected with WNV and for studies of the ecology of WNV.

Authors

Andreadis, Theodore G., Anderson, John F., Vossbrinck, Charles R., Main, Andy J. and Ferrandino, Francis J.

Year Published

2006

Publication

Journal of Medical Entomology

Locations
DOI

10.1603/0022-2585(2006)43[1010:WNVFFA]2.0.CO;2

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/17017241

Importance of Vertical and Horizontal Transmission of West Nile Virus by Culex pipiens in the Northeastern United States Anderson, John F.2006

Importance of Vertical and Horizontal Transmission of West Nile Virus by Culex pipiens in the Northeastern United States

Keywords

WNV

Abstract

West Nile virus (WNV) has become established in the northeastern United States, where mosquitoes are inactive during winter. There have been no documented studies to explain how this virus survives winter and reinitiates infection in spring. We report that WNV was vertically transmitted to 2 F1 female Culex pipiens from a naturally infected female collected in Stratford, Connecticut. One vertically infected F1 female, which was 168 days old, fed on a hamster that died 8 days later of West Nile disease. This suggests that WNV survives winter in unfed, vertically infected C. pipiens with amplification initiated in spring by horizontal transmission

Authors

Anderson, John F. and Main, Andy J.

Year Published

2006

Publication

The Journal of Infectious Diseases

Locations
DOI

10.1086/508754

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/17083043

Wintering of Neurotropic Velogenic Newcastle Disease Virus and West Nile Virus in Double-Crested Cormorants (Phalacrocorax auritus) from the Florida KeysAllison, A. B.2005

Wintering of Neurotropic Velogenic Newcastle Disease Virus and West Nile Virus in Double-Crested Cormorants (Phalacrocorax auritus) from the Florida Keys

Keywords

Newcastle disease virus, double-crested cormorant, fusion protein, West Nile virus, Florida, wintering grounds, reservoir, WNV

Abstract

During 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.

Authors

Allison, A. B., Gottdenker, N. L. and Stallknecht, D. E.

Year Published

2005

Publication

Avian Diseases

Locations
DOI

10.1637/7278-091304R

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/16094838

HEMATOLOGY, PLASMA BIOCHEMISTRY, AND ANTIBODIES TO SELECT VIRUSES IN WILD-CAUGHT EASTERN MASSASAUGA RATTLESNAKES (SISTRURUS CATENATUS CATENATUS) FROM ILLINOISAllender, Matthew C.2006

HEMATOLOGY, PLASMA BIOCHEMISTRY, AND ANTIBODIES TO SELECT VIRUSES IN WILD-CAUGHT EASTERN MASSASAUGA RATTLESNAKES (SISTRURUS CATENATUS CATENATUS) FROM ILLINOIS

Keywords

Biochemistry, hematology, massasauga, ophidian paramyxovirus, rattlesnake, serology, Sistrurus catenatus catenatus, West Nile virus, WNV

Abstract

During the 2004 field season, blood was collected from Eastern massasauga rattlesnakes (Sistrurus catenatus catenatus) in the Carlyle Lake (Carlyle, Illinois, USA) and Allerton Park (Monticello, Illinois, USA) populations to derive baseline complete blood count and plasma biochemistry data and to assess the prevalence of antibodies to West Nile virus (WNV) and ophidian paramyxovirus (OPMV). Massasaugas were located for sampling through visual encounter surveys. Body weight, snout–vent length, total protein, globulins, sodium, and potassium were normally distributed among the survey population. Aspartate aminotransferase, creatine kinase, albumin, calcium, uric acid, white blood cell count, heterophils, lymphocytes, monocytes, eosinophils, and basophils were non-normally distributed within these animals. Female snakes had significantly shorter tail lengths; lower blood glucose, packed cell volumes, and absolute azurophil counts; and higher plasma calcium and phosphorus concentrations than did males. None of the snakes tested (n=21) were seropositive for WNV, whereas all (n=20) were seropositive for OPMV.

Authors

Allender, Matthew C., Mitchell, Mark A., Phillips, Christopher A., Gruszynski, Karen and Beasley, Val R.

Year Published

2006

Publication

Journal of Wildlife Diseases

Locations
DOI

10.7589/0090-3558-42.1.107

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/16699153

Ecological correlates of risk and incidence of West Nile virus in the United StatesAllan, Brian F.2009

Ecological correlates of risk and incidence of West Nile virus in the United States

Keywords

WNV

Abstract

West Nile virus, which was recently introduced to North America, is a mosquito-borne pathogen that infects a wide range of vertebrate hosts, including humans. Several species of birds appear to be the primary reservoir hosts, whereas other bird species, as well as other vertebrate species, can be infected but are less competent reservoirs. One hypothesis regarding the transmission dynamics of West Nile virus suggests that high bird diversity reduces West Nile virus transmission because mosquito blood-meals are distributed across a wide range of bird species, many of which have low reservoir competence. One mechanism by which this hypothesis can operate is that high-diversity bird communities might have lower community-competence, defined as the sum of the product of each species' abundance and its reservoir competence index value. Additional hypotheses posit that West Nile virus transmission will be reduced when either: (1) abundance of mosquito vectors is low; or (2) human population density is low. We assessed these hypotheses at two spatial scales: a regional scale near Saint Louis, MO, and a national scale (continental USA). We found that prevalence of West Nile virus infection in mosquito vectors and in humans increased with decreasing bird diversity and with increasing reservoir competence of the bird community. Our results suggest that conservation of avian diversity might help ameliorate the current West Nile virus epidemic in the USA.

Authors

Allan, Brian F., Langerhans, R. Brian, Ryberg, Wade A., Landesman, William J., Griffin, Nicholas W., Katz, Rachael S., Oberle, Brad J., Schutzenhofer, Michele R., Smyth, Kristina N., St. Maurice, Annabelle, Clark, Larry, Crooks, Kevin R., Hernandez, Daniel E., McLean, Robert G., Ostfeld, Richard S. and Chase, Jonathan M.

Year Published

2009

Publication

Oecologia

Locations
DOI

10.1007/s00442-008-1169-9

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18941794

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