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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
NONTARGET EFFECTS OF THE MOSQUITO ADULTICIDE PYRETHRIN APPLIED AERIALLY DURING A WEST NILE VIRUS OUTBREAK IN AN URBAN CALIFORNIA ENVIRONMENTBOYCE, WALTER M.2007

NONTARGET EFFECTS OF THE MOSQUITO ADULTICIDE PYRETHRIN APPLIED AERIALLY DURING A WEST NILE VIRUS OUTBREAK IN AN URBAN CALIFORNIA ENVIRONMENT

Keywords

Ultra-low volume adulticide, nontarget mortality, pyrethrins, WNV

Abstract

In August 2006, a pyrethrin insecticide synergized with piperonyl butoxide (EverGreen® Crop Protection EC 60-6, McLaughlin Gormley King Company, Golden Valley, MN) was sprayed in ultra-low volumes over the city of Davis, CA, by the Sacramento–Yolo Mosquito and Vector Control District to control mosquitoes transmitting West Nile virus. Concurrently, we evaluated the impact of the insecticide on nontarget arthropods by 1) comparing mortality of treatment and control groups of sentinel arthropods, and 2) measuring the diversity and abundance of dead arthropods found on treatment and control tarps placed on the ground. We found no effect of spraying on nontarget sentinel species including dragonflies (Sympetrum corruptum), spiders (Argiope aurantia), butterflies (Colias eurytheme), and honeybees (Apis mellifera). In contrast, significantly higher diversity and numbers of nontarget arthropods were found on ground tarps placed in sprayed versus unsprayed areas. All of the dead nontarget species were small-bodied arthropods as opposed to the large-bodied sentinels that were not affected. The mortality of sentinel mosquitoes placed at the same sites as the nontarget sentinels and ground tarps ranged from 0% to 100%. Dead mosquitoes were not found on the ground tarps. We conclude that aerial spraying with pyrethrins had no impact on the large-bodied arthropods placed in the spray zone, but did have a measurable impact on a wide range of small-bodied organisms.

Authors

Reisen, William K., BOYCE, WALTER M., LAWLER, SHARON P., SCHULTZ, JENNIFER M., McCAULEY, SHANNON J., KIMSEY, LYNN S., NIEMELA, MICHAEL K. and NIELSEN, CARRIE F.

Year Published

2007

Publication

Journal of the American Mosquito Control Association

Locations
DOI

10.2987/8756-971X(2007)23[335:NEOTMA]2.0.CO;2

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/17939516

ENTOMOLOGICAL STUDIES ALONG THE COLORADO FRONT RANGE DURING A PERIOD OF INTENSE WEST NILE VIRUS ACTIVITYBOLLING, B.G.2007

ENTOMOLOGICAL STUDIES ALONG THE COLORADO FRONT RANGE DURING A PERIOD OF INTENSE WEST NILE VIRUS ACTIVITY

Keywords

West Nile virus, vector ecology, Culex pipiens, Culex tarsalis, overwintering, WNV

Abstract

To better understand the ecology of West Nile virus transmission in Northern Colorado, field studies were conducted in Larimer and Weld counties from September 2003 through March 2005. During summer studies, 18,540 adult mosquitoes were collected using light traps and gravid traps. West Nile virus RNA was detected in 24 of the 2,140 mosquito pools tested throughout the study area in 2003 and 2004. Culex tarsalis had the highest minimum infection rate (MIR) in both 2003 (MIR  =  34.48) and in 2004 (MIR  =  8.74). During winter studies, 9,391 adult mosquitoes were collected by aspirator from various overwintering sites including bridges and storm drains. The most frequently collected species was Culex pipiens. West Nile virus was not detected in our overwintering collections. The relationship between spring adult emergence and temperature inside and outside overwintering sites is described. Species composition of collections as well as the spatial and temporal distribution of West Nile virus detections are presented.

Authors

BOLLING, B.G., MOORE, C.G., ANDERSON, S.L., BLAIR, C.D. and BEATY, B.J.

Year Published

2007

Publication

Journal of the American Mosquito Control Association

Locations
DOI

10.2987/8756-971X(2007)23[37:ESATCF]2.0.CO;2

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/17536366

URBAN HABITAT EVALUATION FOR WEST NILE VIRUS SURVEILLANCE IN MOSQUITOES IN ALBUQUERQUE, NEW MEXICODiMenna, Mark A.2007

URBAN HABITAT EVALUATION FOR WEST NILE VIRUS SURVEILLANCE IN MOSQUITOES IN ALBUQUERQUE, NEW MEXICO

Keywords

Albuquerque, New Mexico, mosquitoes, West Nile virus, surveillance, WNV

Abstract

As part of an ongoing mosquito surveillance program, 27 sites in the greater metropolitan Albuquerque area (Bernalillo County, New Mexico) were trapped from May through September 2004. Each site was sampled for 1 night weekly, using a standard CO2-baited Centers for Disease Control and Prevention light trap and a gravid trap. Captured mosquitoes were catalogued by location, species, and date, and selected pools were tested for West Nile virus (WNV) by reverse transcription–polymerase chain reaction. Based on previous surveillance, WNV was already established in the state of New Mexico. Surveillance during 2003, the 1st year of WNV detection in New Mexico mosquitoes, was focused on the bosque forest of the Rio Grande river valley. Surveillance during summer of 2004 was extended to additional areas around the city of Albuquerque, the state's largest population center. In addition to the standard surveillance objectives, a secondary goal was to determine whether foci of WNV activity were detectable in other habitats besides the riparian ecosystem of the Rio Grande, and in other species not previously identified as vectors. There was no demonstrable advantage to extending the traditional trapping area outside of the Rio Grande valley. Sites in the valley area had WNV-positive mosquitoes earlier in the season, and for a longer period than the added sites. In addition, riparian sites had the highest diversity of species, the largest numbers of Culex spp. captured, and the largest proportion of the WNV-positive mosquito pools from the study. Species found in other areas of the metropolitan area were also represented in the valley. Although WNV activity was detected in other areas of the city, its activity began later and ended earlier than in the river valley. We surmise that the greatest benefit to mosquito surveillance could be achieved by focusing on the river valley area.

Authors

Parmenter, Robert R., DiMenna, Mark A., Bueno, Rudy, Norris, Douglas E., Sheyka, Jeff M., Molina, Josephine L., LaBeau, Elisa M., Hatton, Elizabeth S., Glass, Gregory E. and ROBERTS, CHRISTINE M.

Year Published

2007

Publication

Journal of the American Mosquito Control Association

Locations
DOI

10.2987/8756-971X(2007)23[153:UHEFWN]2.0.CO;2

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/17847847

Land Use and West Nile Virus Seroprevalence in Wild MammalsGómez, Andrés2008

Land Use and West Nile Virus Seroprevalence in Wild Mammals

Keywords

WNV

Abstract

We examined West Nile virus (WNV) seroprevalence in wild mammals along a forest-to-urban gradient in the US mid-Atlantic region. WNV antibody prevalence increased with age, urbanization, and date of capture for juveniles and varied significantly between species. These findings suggest several requirements for using mammals as indicators of transmission.

Authors

Kramer, Laura D., Kilpatrick, A. Marm, Marra, Peter P., Daszak, Peter, Dupuis, Alan P., Maffei, Joseph G., Gómez, Andrés, Goetz, Scott J. and Aguirre, A. Alonso

Year Published

2008

Publication

Emerging Infectious Diseases

Locations
DOI

10.3201/eid1406.070352

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18507915

A Method to Increase Efficiency in Testing Pooled Field-Collected MosquitoesChisenhall, Daniel M.2008

A Method to Increase Efficiency in Testing Pooled Field-Collected Mosquitoes

Keywords

West Nile virus, mosquito pool, quantitative reverse transcriptase polymerase chain reaction, arbovirus testing, surveillance, WNV

Abstract

Testing field-caught mosquito collections can result in thousands of pools, and testing pools of 50 mosquitoes each can be both time consuming and cost prohibitive. Consequently, we have developed an alternative approach to testing mosquito pools for arboviruses, utilizing a superpool strategy. When mosquito samples are processed for extraction of viral RNA and subsequent virus testing via quantitative real-time polymerase chain reaction, each pool is tested individually. Using the method described here, 0.025 ml from each of 10 pools is combined into a superpool for RNA extraction and testing. When a virus-positive superpool sample is found, each of the original 10 pools that constitute this sample is tested individually in order to find the specific positive sample. By retesting the original samples after the initial superpool screen, we are still able to obtain reliable estimates for minimum infection rates or maximum likelihood estimations. To test this principle, we created controlled mosquito pools of known titer and subjected them to our superpool process. We were able to detect our entire range of laboratory-created pools as being West Nile virus (WNV) positive. In 2005, field surveillance efforts from our laboratory resulted in over 4,000 mosquito pools tested, with 8 resulting WNV-positive samples. We found that all of these field samples were detected as WNV positive using the superpool method and contained calculated virus titers from <0.1 to 4.1 log10 plaque-forming units/ml WNV, indicating that the limit of superpool detection of WNV is below this point. These results reveal that the superpool method could be accurately used to detect WNV in field-collected specimens.

Authors

Chisenhall, Daniel M., Vitek, Christopher J., Richards, Stephanie L. and Mores, Christopher N.

Year Published

2008

Publication

Journal of the American Mosquito Control Association

Locations
DOI

10.2987/5671.1

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18666541

Delinquent Mortgages, Neglected Swimming Pools, and West Nile Virus, CaliforniaReisen, William K.2008

Delinquent Mortgages, Neglected Swimming Pools, and West Nile Virus, California

Keywords

WNV

Abstract

Adjustable rate mortgages and the downturn in the California housing market caused a 300% increase in notices of delinquency in Bakersfield, Kern County. This led to large numbers of neglected swimming pools, which were associated with a 276% increase in the number of human West Nile virus cases during the summer of 2007.

Authors

Reisen, William K., Takahashi, Richard M., Carroll, Brian D. and Quiring, Rob

Year Published

2008

Publication

Emerging Infectious Diseases

Locations
DOI

10.3201/eid1411.080719

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18976560

Effects of Single and Multiple Applications of Mosquito Insecticides on Nontarget ArthropodsDavis, Ryan S.2008

Effects of Single and Multiple Applications of Mosquito Insecticides on Nontarget Arthropods

Keywords

Mosquito control, adulticide, larvicide, ecological risk, nontarget organisms, West Nile virus, WNV

Abstract

Mosquito management plans have been implemented in the United States and globally to manage mosquito vectors of West Nile virus and many other diseases. However, there is public concern about ecological risks from using insecticides to manage mosquitoes. Two studies were conducted during the late summers of 2004 through 2006 at Benton Lake National Wildlife Refuge near Great Falls, MT. The first experiment was conducted in 2004 and 2005 to assess acute impacts of mosquito adulticides (permethrin and d-phenothrin) and larvicides (Bacillus thuringiensis israelensis and methoprene) on nontarget aquatic and terrestrial arthropods after a single application. The second experiment was conducted in 2005 and 2006 to assess longer-term impacts of permethrin on nontarget terrestrial arthropods after multiple repeated applications. For aquatic samples, in the first study, no overall treatment effects were observed despite a potentially deleterious effect on amphipods on sample date 1 in 2004. During the same study, 1 of 54 responses had a significant overall treatment effect for sticky-card samples. Many of the responses for sticky-card samples suggested significant time effects and time × treatment effects. Three response variables were associated with fewer individuals present in the insecticide-treated plots in a multivariate analysis. For the multiple-spray study conducted in 2005 and 2006, 6 of the response variables collected via sticky cards exhibited significant overall treatment effects, but none was associated with fewer individuals in the insecticide-treated plots. None of the responses collected using sweep-net sampling suggested overall treatment effects. Time and time × treatment effects were prevalent in 2005, but no discernable pattern was evident. In general, nearly all of the responses evaluated for either study indicated few, if any, deleterious effects from insecticide application.

Authors

Davis, Ryan S. and Peterson, Robert K. D.

Year Published

2008

Publication

Journal of the American Mosquito Control Association

Locations
DOI

10.2987/5654.1

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18666536

Intensive Early Season Adulticide Applications Decrease Arbovirus Transmission Throughout the Coachella Valley, Riverside County, CaliforniaLothrop, Hugh D.2008

Intensive Early Season Adulticide Applications Decrease Arbovirus Transmission Throughout the Coachella Valley, Riverside County, California

Keywords

WNV

Abstract

In the Coachella Valley of California the seasonal onset of St. Louis encephalitis virus (SLEV), western equine encephalomyelitis virus (WEEV), and West Nile virus (WNV) has been detected consistently at the shoreline of the Salton Sea near the community of North Shore. The timing and intensity of initial amplification in the Culex tarsalis Coquillett/wild bird cycle at this focus seemed closely linked to the subsequent dispersal of virus to the rest of the Coachella Valley and perhaps southern California. In 2004, an attempt was made to interrupt the amplification and dispersal of WNV using ground ultra-low volume (ULV) applications of Pyrenone 25-5®. Although these localized treatments were started 1 month after the initial detection in April, surveillance indicated no dispersal from this focus at this time. However, these treatments appeared to have little effect, and WNV eventually was detected throughout the valley, with seven human cases reported in the urbanized upper valley near Palm Springs. In 2005, the initial detection of WNV at North Shore at the end of May was followed rapidly by dispersal throughout the valley precluding efforts at containment. Evaluation of ground and aerial applications at North Shore during May and June 2005, respectively, indicated variable kill of sentinel mosquitoes (overall mortality: ground, 43%; air, 34%) and limited control of the target Cx. tarsalis population. In 2006, aerial ULV applications with the same chemical were begun immediately following the first detection of virus in mid-April, resulting in an apparent reduction of Cx. tarsalis abundance and delay of WNV activity in the rural lower valley and a marked decline in transmission by Culex quinquefasciatus Say populations in the densely populated upper northwestern valley with no human cases reported.

Authors

Reisen, William K., Lothrop, Hugh D., Lothrop, Branka B. and Gomsi, Donald E.

Year Published

2008

Publication

Vector-Borne and Zoonotic Diseases

Locations
DOI

10.1089/vbz.2007.0238

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18494603

Increased Avian Diversity Is Associated with Lower Incidence of Human West Nile Infection: Observation of the Dilution EffectSwaddle, John P.2008

Increased Avian Diversity Is Associated with Lower Incidence of Human West Nile Infection: Observation of the Dilution Effect

Keywords

WNV

Abstract

Recent infectious disease models illustrate a suite of mechanisms that can result in lower incidence of disease in areas of higher disease host diversity–the ‘dilution effect’. These models are particularly applicable to human zoonoses, which are infectious diseases of wildlife that spill over into human populations. As many recent emerging infectious diseases are zoonoses, the mechanisms that underlie the ‘dilution effect’ are potentially widely applicable and could contribute greatly to our understanding of a suite of diseases. The dilution effect has largely been observed in the context of Lyme disease and the predictions of the underlying models have rarely been examined for other infectious diseases on a broad geographic scale. Here, we explored whether the dilution effect can be observed in the relationship between the incidence of human West Nile virus (WNV) infection and bird (host) diversity in the eastern US. We constructed a novel geospatial contrasts analysis that compares the small differences in avian diversity of neighboring US counties (where one county reported human cases of WNV and the other reported no cases) with associated between-county differences in human disease. We also controlled for confounding factors of climate, regional variation in mosquito vector type, urbanization, and human socioeconomic factors that are all likely to affect human disease incidence. We found there is lower incidence of human WNV in eastern US counties that have greater avian (viral host) diversity. This pattern exists when examining diversity-disease relationships both before WNV reached the US (in 1998) and once the epidemic was underway (in 2002). The robust disease-diversity relationships confirm that the dilution effect can be observed in another emerging infectious disease and illustrate an important ecosystem service provided by biodiversity, further supporting the growing view that protecting biodiversity should be considered in public health and safety plans.

Authors

Swaddle, John P. and Calos, Stavros E.

Year Published

2008

Publication

PLOS One

Locations
DOI

10.1371/journal.pone.0002488

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18575599

Meteorologically Conditioned Time-Series Predictions of West Nile Virus Vector MosquitoesTrawinski, P.R.2008

Meteorologically Conditioned Time-Series Predictions of West Nile Virus Vector Mosquitoes

Keywords

WNV

Abstract

An empirical model to forecast West Nile virus mosquito vector populations is developed using time series analysis techniques. Specifically, multivariate seasonal autoregressive integrated moving average (SARIMA) models were developed for Aedes vexans and the combined group of Culex pipiens and Culex restuans in Erie County, New York. Weekly mosquito collections data were obtained for the four mosquito seasons from 2002 to 2005 from the Erie County Department of Health, Vector and Pest Control Program. Climate variables were tested for significance with cross-correlation analysis. Minimum temperature (Tmin), maximum temperature (Tmax), average temperature (Tave), precipitation (P), relative humidity (RH), and evapotranspiration (ET) were acquired from the Northeast Regional Climate Center (NRCC) at Cornell University. Weekly averages or sums of climate variables were calculated from the daily data. Other climate indexes were calculated and were tested for significance with the mosquito population data, including cooling degree days base 60 degrees (CDD_60), cooling degree days base 63 (CDD_63), cooling degree days base 65 (CDD_65), a ponding index (IP), and an interactive CDD_65-precipitation variable (CDD_65 × Pweek_4). Ae. vexans were adequately modeled with a (2,1,1)(1,1,0)52 SARIMA model. The combined group of Culex pipiens-restuans were modeled with a (0,1,1)(1,1,0)52 SARIMA model. The most significant meteorological variables for forecasting Aedes vexans abundance was the interactive CDD_65 × Pweek_4 variable at a lag of two weeks, ET × ET at a lag of five weeks, and CDD_65 × CDD_65 at a lag of seven weeks. The most significant predictive variables for the grouped Culex pipiens-restuans were CDD_63 × CDD_63 at a lag of zero weeks, CDD_63 at a lag of eight weeks, and the cumulative maximum ponding index (IPcum) at a lag of zero weeks.

Authors

Trawinski, P.R. and MacKay, D.S.

Year Published

2008

Publication

Vector-Borne and Zoonotic Diseases

Locations
DOI

10.1089/vbz.2007.0202

Additional Information:

http://www.ncbi.nlm.nih.gov/pubmed/18279008

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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...

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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