| Completeness of West Nile virus testing in patients with meningitis and encephalitis during an outbreak in Arizona, USA | WEBER, I. B. | 2012 |
KeywordsWNV AbstractAccurate 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 tested for WNV. Only 12 (28%) of 43 patients aged <0·01). Patients with clinical signs of weakness or paralysis, elevated CSF protein, admitted to an inpatient facility, or discharged to a rehabilitation facility were also more likely to have WNV testing performed. The lack of testing in younger age groups and in those with less severe disease probably resulted in substantial underestimates of WNV neuroinvasive disease burden. AuthorsWEBER, 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. Year Published2012 PublicationEpidemiology and Infection LocationsDOI10.1017/S0950268811002494 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/22123531 |
| Aquatic Effects of Aerial Spraying for Mosquito Control over an Urban Area | Weston, Donald P. | 2006 |
KeywordsWNV AbstractIn an effort to combat West Nile Virus, planes dispersed insecticide over Sacramento, CA, treating nearly 50,000 hectares with pyrethrins and the synergist piperonyl butoxide (PBO). Widespread dispersal of insecticide over a metropolitan area, coupled with extensive pretreatment data on the area's urban creeks, provided a unique opportunity to study effects of mosquito control agents on aquatic habitats within an urban setting. There was no evidence of aquatic toxicity from the two active ingredients in the product applied. However, PBO concentrations were high enough to enhance toxicity of pyrethroids already existing in creek sediments from general urban pesticide use. PBO concentrations of 2−4 μg/L were high enough to nearly double the toxicity of sediments to the amphipod Hyalella azteca. Though the increase in toxicity was modest, it was unexpected to find environmental synergy at all. Risk assessments for mosquito control agents have focused on the active ingredients but have failed to recognize the potential for interactions with pesticides previously existing in the environment, which in this case appeared to represent a risk to aquatic life greater than that of the active ingredients themselves. AuthorsWeston, Donald P., Amweg, Erin L., Mekebri, Abdou, Ogle, R. Scott and Lydy, Michael J. Year Published2006 PublicationEnvironmental Science & Technology LocationsDOI10.1021/es0601540 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/17007146 |
| Vector Surveillance for West Nile Virus | WHITE, DENNIS J. | 2001 |
KeywordsWNV AbstractWest 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. AuthorsWHITE, DENNIS J. Year Published2001 PublicationAnnals of the New York Academy of Sciences LocationsDOI10.1111/j.1749-6632.2001.tb02686.x Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/11797806 |
| Identification of hyperendemic foci of horses with West Nile virus disease in Texas | Wittich, Courtney A. | 2008 |
KeywordsWNV AbstractObjective—To determine whether West Nile virus (WNV) disease hyperendemic foci (hot spots) exist within the horse population in Texas and, if detected, to identify the locations.
Sample Population—Reports of 1,907 horses with WNV disease in Texas from 2002 to 2004.
Procedures—Case data with spatial information from WNV epidemics occurring in 2002 (1,377 horses), 2003 (396 horses), and 2004 (134 horses) were analyzed by use of the spatial scan statistic (Poisson model) and kriging of empirical Bayes smoothed county attack rates to determine locations of horses with WNV disease in which affected horses were consistently (in each of the 3 study years) clustered (hyperendemic foci, or hot spots).
Results—2 WNV hot spots in Texas, an area in northwestern Texas and an area in eastern Texas, were identified with the scan statistic. Risk maps of the WNV epidemics were qualitatively consistent with the hot spots identified.
Conclusions and Clinical Relevance—WNV hot spots existed within the horse population in Texas (2002 to 2004). Knowledge of disease hot spots allows disease control and prevention programs to be made more efficient through targeted surveillance and education. AuthorsWard, Michael P., Wittich, Courtney A., Fosgate, Geoffrey T. and Srinivasan, Raghavan Year Published2008 PublicationAmerican Journal of Veterinary Research LocationsDOI10.2460/ajvr.69.3.378 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/18312137 |
| Mosquito Larval Habitat Mapping Using Remote Sensing and GIS: Implications of Coalbed Methane Development and West Nile Virus | Zou, Li | 2006 |
KeywordsCulex tarsalis, risk, discharge water, WNV AbstractPotential larval habitats of the mosquito Culex tarsalis (Coquillett), implicated as a primary vector of West Nile virus in Wyoming, were identified using integrated remote sensing and geographic information system (GIS) analyses. The study area is in the Powder River Basin of north central Wyoming, an area that has been undergoing a significant increase in coalbed methane gas extractions since the late 1990s. Large volumes of water are discharged, impounded, and released during the extraction of methane gas, creating aquatic habitats that have the potential to support immature mosquito development. Landsat TM and ETM+ data were initially classified into spectrally distinct water and vegetation classes, which were in turn used to identify suitable larval habitat sites. This initial habitat classification was refined using knowledge-based GIS techniques requiring spatial data layers for topography, streams, and soils to reduce the potential for overestimation of habitat. Accuracy assessment was carried out using field data and high-resolution aerial photography commensurate with one of the Landsat images. The classifier can identify likely habitat for ponds larger than 0.8 ha (2 acres) with generally satisfactory results (72.1%) with a lower detection limit of ≈0.4 ha (1 acre). Results show a 75% increase in potential larval habitats from 1999 to 2004 in the study area, primarily because of the large increase in small coalbed methane water discharge ponds. These results may facilitate mosquito abatement programs in the Powder River Basin with the potential for application throughout the state and region. AuthorsMiller, Scott N., Zou, Li and Schmidtmann, Edward T. Year Published2006 PublicationJournal of Medical Entomology LocationsDOI10.1603/0022-2585(2006)43[1034:MLHMUR]2.0.CO;2 Additional Information:http://www.ncbi.nlm.nih.gov/pubmed/17017244 |
