west nile virus activity--united states, october 20-26, 2004.during october 20-26, a total of 80 cases of human west nile virus (wnv) illness were reported from 16 states (arizona, california, florida, iowa, kentucky, louisiana, michigan, mississippi, missouri, montana, nebraska, new york, ohio, south dakota, texas, and utah).200415514584
spatio-temporal cluster analysis of county-based human west nile virus incidence in the continental united states.west nile virus (wnv) is a vector-borne illness that can severely affect human health. after introduction on the east coast in 1999, the virus quickly spread and became established across the continental united states. however, there have been significant variations in levels of human wnv incidence spatially and temporally. in order to quantify these variations, we used kulldorff's spatial scan statistic and anselin's local moran's i statistic to uncover spatial clustering of human wnv incidence ...200919594928
stable fly phenology in a mixed agricultural--wildlife ecosystem in northeast montana.the stable fly, stomoxys calcitrans (l.), is a cosmopolitan species of blood-feeding muscidae and an important pest of cattle. although the cattle industry is the largest commodity in montana, no research has been conducted on the abundance, distribution, or impact of stable flies in the state. observations of stable flies attacking west nile virus (family flaviviridae, genus flavivirus, wnv) -infected pelicans on a refuge in close proximity to pastured and confined cattle provided an opportunit ...201323339785
mosquito and west nile virus surveillance in northeast montana, u.s.a., 2005 and 2006.mosquito and west nile virus (wnv) surveillance was conducted on a national wildlife refuge in northeast montana in 2005 and 2006, during which outbreaks of wnv in a colony of american white pelicans (pelecanus erythrorhynchos gmelin) (pelecaniformes: pelecanidae) resulted in juvenile mortality rates of ∼ 31%. both years, floodwater species ochlerotatus dorsalis (meigen) (diptera: culicidae), aedes vexans (meigen) (diptera: culicidae) and ochlerotatus flavescens (muller) (diptera: culicidae) com ...201423647177
evaluation of methods for collecting blood-engorged mosquitoes from habitats within a wildlife refuge.mortality of american white pelican (pelecanus erythrorhynchos) chicks attributed to west nile virus (wnv) prompted field studies on the bionomics of mosquitoes on a wildlife refuge in northern montana. one component of these studies was to identify blood meal sources for culex tarsalis, the primary vector of wnv in the region, and the potential bridge vectors aedes vexans and culiseta inornata. to accomplish this, 3 methods were evaluated to collect bloodfed mosquitoes: a gasoline powered aspir ...201323923324
using undergraduate researchers to build vector and west nile virus surveillance capacity.vector surveillance for infectious diseases is labor intensive and constantly threatened by budget decisions. we report on outcomes of an undergraduate research experience designed to build surveillance capacity for west nile virus (wnv) in montana (usa). students maintained weekly trapping stations for mosquitoes and implemented assays to test for wnv in pools of culex tarsalis. test results were verified in a partnership with the state health laboratory and disseminated to the arbonet surveill ...201323912200
vector competence of the stable fly (diptera: muscidae) for west nile 2006-2007, stable flies, stomoxys calcitrans (l.) (diptera: muscidae), were suspected of being enzootic vectors of west nile virus (family flaviviridae, genus flavivirus, wnv) during a die-off of american white pelicans (pelecanus erythrorhynchos gmelin) (pelecanidae) in montana, usa. wnv-positive stable flies were observed feeding en masse on incapacitated, wnv-positive pelicans, arousing suspicions that the flies could have been involved in wnv transmission among pelicans, and perhaps to li ...201121661328
human jamestown canyon virus infection --- montana, 2009.jamestown canyon virus (jcv) is a mosquito-borne zoonotic pathogen belonging to the california serogroup of bunyaviruses. although jcv is widely distributed throughout temperate north america, reports of human jcv infection in the united states are rare. this is the first report of human jcv infection detected in montana, one of only 15 cases reported in the united states since 2004, when jcv became reportable. on may 26, 2009, a man aged 51 years with no travel history outside of montana went t ...201121617630
surveillance for west nile virus in american white pelicans, montana, usa, 2006-2007.west nile virus (wnv)-associated deaths of american white pelican (pelecanus erythrorhynchos) chicks have been recognized at various nesting colonies in the united states since 2002. we evaluated american white pelican nesting colonies in sheridan county, montana, usa, for an association between wnv-positive pelican carcasses and human west nile neuroinvasive disease. persons in counties hosting affected colonies had a 5x higher risk for disease than those in counties with unaffected colonies. w ...201020202414
ecological niche of the 2003 west nile virus epidemic in the northern great plains of the united states.the incidence of west nile virus (wnv) has remained high in the northern great plains compared to the rest of the united states. however, the reasons for the sustained high risk of wnv transmission in this region have not been determined. to assess the environmental drivers of wnv in the northern great plains, we analyzed the county-level spatial pattern of human cases during the 2003 epidemic across a seven-state region.200819057643
effects of single and multiple applications of mosquito insecticides on nontarget arthropods.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 ...200818666536
liver metal concentrations in greater sage-grouse (centrocercus urophasianus).greater sage-grouse (centrocercus urophasianus) are a species of concern due to shrinking populations associated with habitat fragmentation and loss. baseline health parameters for this species are limited or lacking, especially with regard to tissue metal concentrations. to obtain a range of tissue metal concentrations, livers were collected from 71 greater sage-grouse from wyoming and montana. mean +/- se metal concentrations (mg/kg wet weight) in liver were determined for vanadium (v) (0.12 + ...200818436686
factors contributing to process variance in annual survival of female greater sage-grouse in montana.populations of greater sage-grouse (centrocercus urophasianus) have declined by 69-99% from historic levels, and information on population dynamics of these birds at a landscape scale is essential to informed management. we examined the relationships between hen survival and a suite of landscape-scale habitat and environmental conditions. we radio-marked 237 female sage-grouse and measured 426 vegetation plots during 2001-2004 at four sites in a 3200-km2 landscape in north-central montana, usa. ...200616937816
cerebrospinal fluid neutrophilic pleocytosis in hospitalized west nile virus patients.a description of 7 consecutive patients admitted for various forms of neurological impairment. all these patients were found to have cerebrospinal fluid positive for west nile virus igm, and routine bacterial cultures were negative. six of these patients did not present with the typical lymphocytic pleocytosis often quoted when discussing a viral meningitis/encephalitis; rather most presented with a cerebrospinal fluid neutrophilia.200415575040
west nile virus activity--united states, september 22-28, 2004.during september 22-28, a total of 180 cases of human west nile virus (wnv) illness were reported in the district of columbia (dc) and 24 states (alabama, arizona, california, georgia, illinois, iowa, kansas, kentucky, louisiana, maryland, michigan, minnesota, mississippi, missouri, montana, nebraska, nevada, new mexico, ohio, pennsylvania, texas, utah, wisconsin, and wyoming).200415457147
west nile virus activity--united states, august 25-31, 2004.during august 25-31, a total of 210 cases of human west nile virus (wnv) illness were reported from 14 states (arizona, california, florida, illinois, indiana, kansas, maryland, minnesota, montana, nevada, new mexico, north dakota, oklahoma, and pennsylvania).200415343148
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