genetic variation among temporally and geographically distinct west nile virus isolates, united states, 2001, 2002.analysis of partial nucleotide sequences of 22 west nile virus (wnv) isolates collected during the summer and fall of 2001 and 2002 indicated genetic variation among strains circulating in geographically distinct regions of the united states and continued divergence from isolates collected in the northeastern united states during 1999 and 2000. sequence analysis of a 2,004-nucleotide region showed that 14 isolates shared two nucleotide mutations and one amino acid substitution when they were com ...200314718086
the 2002 introduction of west nile virus into harris county, texas, an area historically endemic for st. louis encephalitis.harris county, texas, is an endemic area of st. louis encephalitis (sle); and an active surveillance program that monitors sle virus activity in mosquitoes, birds, and humans has been in place there for the past 28 years. in june of 2002, west nile (wn) virus appeared in houston and quickly spread throughout the region. this report describes the results of 12 years of sle surveillance in harris county and the contrasting pattern of wn virus activity, when it arrived in 2002. our data indicate th ...200415211013
west nile virus activity--united states, september 8-14, 2004.during september 8-14, a total of 195 cases of human west nile virus (wnv) illness were reported from 26 states (alabama, arizona, arkansas, california, colorado, florida, georgia, idaho, illinois, iowa, kansas, maryland, minnesota, missouri, nebraska, nevada, new mexico, new york, north dakota, oklahoma, oregon, pennsylvania, south dakota, tennessee, texas, and wisconsin).200415371969
year-round west nile virus activity, gulf coast region, texas and louisiana.west 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.200415498169
characterization of a west nile virus isolate from a human on the gulf coast of texas.genetic characterization of a human cerebrospinal fluid west nile virus isolate from beaumont, texas, revealed several nucleotide changes and amino acid substitutions that differentiated it from all other north american strains isolated to date, suggesting that isolates from the texas gulf coast may form a unique genetic group among north american strains.200415528747
first report of west nile virus in mosquitoes from lubbock county, texas.since july 2002, ongoing surveillance efforts have been conducted to determine potential vectors of west nile virus (wnv) and saint louis encephalitis virus (slev) in the mosquito population occurring in lubbock county, texas. adult mosquitoes collected in lubbock county during 2002 and 2003 represented 7 genera, with culex tarsalis and ochlerotatus sollicitans being the predominant species collected. mosquitoes were initially screened for wnv and slev by using the vectest antigen panel assay. p ...200515825772
spread of equine west nile virus encephalomyelitis during the 2002 texas epidemic.using reports of clinical west nile virus (wnv) encephalomyelitis in texas equids during 2002, the distribution of disease was analyzed using cluster statistics and spatial modeling to develop hypotheses of disease spread during the first year of its detection. significant (p < 0.05) clusters of cases reported early during the outbreak were identified in east, northcentral, and north texas, and significant (p < 0.05) clusters late during the outbreak were detected in central, south, and west tex ...200616760526
west nile virus activity--united states, january 1-august 15, 2006.this report summarizes west nile virus (wnv) surveillance data reported to cdc through arbonet as of 3 a.m. mountain daylight time, august 15, 2006. a total of 26 states had reported 388 cases of human wnv illness to cdc. a total of 214 (56%) cases for which such data were available occurred in males; median age of patients was 49 years (range: 2-91 years). dates of illness onset ranged from january 6 to august 10; a total of 13 cases were fatal. a total of 68 presumptive west nile viremic blood ...200616915222
antibodies to west nile virus in feral swine from florida, georgia, and texas, usa.west nile virus (wnv) exposure has not yet been reported in feral swine (sus scrofa) despite the broad geographic range and population density of this species. the objectives of this study were to determine the prevalence of antibodies to wnv in feral pigs, and to evaluate serologic diagnostics as applied to this species. feral pig serum from three states was evaluated for antibodies to wnv. the overall wnv seroprevalence rate for 222 samples collected in 2001-2004 was 22.5%. seroprevalence rate ...200616989565
demographic and spatial analysis of west nile virus and st. louis encephalitis in houston, texas.this descriptive prevalence study describes the relationships between mosquito density and the presence of arboviruses (in mosquitoes and humans) with various socioeconomic and environmental factors present near the time of teh arbovirus outbreak in harris county, texas, in 2002. this study suggests that mosquito density increased if the trap was located in an area with a large number of containers that may inadvertently retain rainwater (p = 0.056). when considering only virus-positive mosquito ...200617019771
depression after infection with west nile virus.previous reports have noted depression after west nile virus (wnv) infection. we further measured this outcome and found that 31% of patients reported new-onset depression and 75% of these had center for epidemiologic studies depression scores indicative of mild-to-severe depression. physicians should be aware of neuropsychiatric consequences of wnv in patients.200717552106
using geographic information systems and spatial and space-time scan statistics for a population-based risk analysis of the 2002 equine west nile epidemic in six contiguous regions of 2002, west nile virus (wnv) first appeared in texas. surveillance data were retrospectively examined to explore the temporal and spatial characteristics of the texas equine wnv epidemic in 2002. using geographic information systems (gis) and the spatial and space-time scan (satscan) statistics, we analyzed 1421 of the reported equine wnv cases from six contiguous state health service regions (hsrs), comprising 158 counties, in western, northern, central and eastern texas.200717888159
associations between two mosquito populations and west nile virus in harris county, texas, 2003-06.associations between culex quinquefasciatus, aedes albopictus and west nile virus (wnv) activity, temperature, and rainfall in harris county, texas 2003-06 are discussed. human cases were highly correlated to cx. quinquefasciatus (r = 0.87) and ae. albopictus (r = 0.78) pools, blue jays (r = 0.83), and ae. albopictus collected (r = 0.71), but not cx. quinquefasciatus collected (r = 0.45). human cases were associated with temperature (r = 0.71), not rainfall (r = 0.29), whereas temperature correl ...200717939505
relative susceptibilties of south texas mosquitoes to infection with west nile virus.three species of mosquitoes (culex pipiens quinquefasciatus, aedes aegypti, and ae. albopictus) collected in texas were compared with respect to their relative susceptibility to infection with west nile virus (wnv) strain 114. oral infection and dissemination rates were 73% infected with 86% dissemination for ae. aegypti, 13% infected with 100% dissemination for ae. albopictus, and 100% infected and disseminated for cx. p. quinquefasciatus. the oral infectious dose required to establish a 50% in ...200717984355
a multiple cage-holding, wind-sensitive vane design for use in ground adulticiding efficacy testing in harris county, texas.a wind-sensitive vane apparatus was designed and implemented specifically to accommodate the attachment of otherwise unidirectional insecticide treatment cages used in ground ultra-low volume mosquito adulticide field tests. this cage support system is useful in keeping the potential west nile virus and st. louis encephalitis vector culex quinquefasciatus caged mosquitoes oriented into the wind during field efficacy tests. testing capacity for resistance surveillance was tripled during the 2005 ...200717847862
host feeding pattern of culex quinquefasciatus (diptera: culicidae) and its role in transmission of west nile virus in harris county, texas.the vertebrate hosts of 672 blood-engorged culex quinquefasciatus say, collected in harris county, texas, during 2005, were identified by nucleotide sequencing pcr products of the cytochrome b gene. analysis revealed that 39.1% had acquired blood from birds, 52.5% from mammals, and 8.3% were mixed avian and mammalian blood meals. most frequent vertebrate hosts were dog (41.0%), mourning dove (18.3%), domestic cat (8.8%), white-winged dove (4.3%), house sparrow (3.2%), house finch (3.0%), gray ca ...200717620633
serologic evidence of west nile virus exposure in north american mesopredators.sera from 936 mammalian mesopredators (virginia opossums, gray foxes, striped skunks, hooded skunks, raccoons, a bobcat, and a red fox) were collected during 2003 and 2004 in california, arizona, texas, louisiana, ohio, and wyoming and screened for flavivirus-specific antibodies by an epitope-blocking enzyme-linked immunosorbent assay (blocking elisa). serum samples positive for antibodies against flaviviruses were screened for west nile virus (wnv)-specific antibodies by blocking elisa and sele ...200717255248
human west nile virus neuroinvasive disease in texas, 2003 epidemic: regional differences.arboviral diseases, such as west nile virus (wnv) epizootics, tend to be geographically unique because of the biomes that support the vector(s) and reservoir host(s). understanding such details aids in preventive efforts. we studied the 2003 epidemic of human west nile neuroinvasive disease (wnnd) in texas because it initially appeared that incidence was not uniform across regions of the state.200616978879
characteristics of an outbreak of west nile virus encephalomyelitis in a previously uninfected population of horses.equine west nile virus (wnv) encephalomyelitis cases - based on clinical signs and elisa serology test results - reported to texas disease control authorities during 2002 were analyzed to provide insights into the epidemiology of the disease within a previously disease-free population. the epidemic occurred between june 27 and december 17 (peaking in early october) and 1,698 cases were reported. three distinct epidemic phases were identified, occurring mostly in southeast, northwest and then cen ...200616971067
seasonal dynamics of four potential west nile vector species in north-central texas.a population survey was conducted from april through september 2002 on mosquito species occurring on the ray roberts greenbelt, a riparian corridor used for public recreation on the elm fork of the trinity river, in denton county, tx. geographic information system software was used to set up a stratified random sampling design based on habitat parameters. mosquitoes were collected using light traps, gravid traps, and resting boxes. a total of 29 species was collected during this study belonging ...200516599151
short report: comparison of oral infectious dose of west nile virus isolates representing three distinct genotypes in culex quinquefasciatus.phylogenetic analysis of west nile virus in north america has identified replacement of the originally introduced clade, eastern united states (ny99), by the north american clade. in addition, the transient emergence of other clades and genetic variants has also been observed. in this study, we investigated the potential role of the mosquito in the selection of these clades and genetic variants. we determined the relative susceptibility of culex quinquefasciatus to infection with isolates from t ...200819052310
west nile virus isolation in human and mosquitoes, mexico.west nile virus has been isolated for the first time in mexico, from a sick person and from mosquitoes (culex quinquefasciatus). partial sequencing and analysis of the 2 isolates indicate that they are genetically similar to other recent isolates from northern mexico and the western united states.200516229779
west nile virus activity--united states, november 9-16, 2004.during november 9-16, a total of 31 cases of human west nile virus (wnv) illness were reported from eight states (arizona, georgia, maryland, michigan, missouri, new york, pennsylvania, and texas).200415549023
genomic sequence and phylogenetic analysis of culex flavivirus, an insect-specific flavivirus, isolated from culex pipiens (diptera: culicidae) in mosquitoes (diptera: culicidae) were collected in 2007 and tested for specific viruses, including west nile virus, as part of the ongoing arbovirus surveillance efforts in the state of iowa. a subset of these mosquitoes (6,061 individuals in 340 pools) was further tested by reverse transcription-polymerase chain reaction (rt-pcr) using flavivirus universal primers. of the 211 pools of culex pipiens (l.) tested, 50 were positive. one of 51 pools of culex tarsalis coquillet was also positive ...200919645300
west nile virus activity--united states, november 3-8, 2004.during november 3-8, a total of 41 cases of human west nile virus (wnv) illness were reported from seven states (california, maryland, minnesota, new mexico, oregon, tennessee, and texas).200415538322
temporal and spatial alterations in mutant swarm size of st. louis encephalitis virus in mosquito louis encephalitis virus (slev; flaviviridae; flavivirus) is a member of the japanese encephalitis serocomplex and a close relative of west nile virus (wnv). although slev remains endemic to the us, both levels of activity and geographical dispersal are relatively constrained when compared to the widespread distribution of wnv. in recent years, wnv appears to have displaced slev in california, yet both viruses currently coexist in texas and several other states. it has become clear that vira ...201121215334
west nile virus infection in killer whale, texas, usa, 2007, nonsuppurative encephalitis was identified in a killer whale at a texas, usa, marine park. panviral dna microarray of brain tissue suggested west nile virus (wnv); wnv was confirmed by reverse transcription pcr and sequencing. immunohistochemistry demonstrated wnv antigen within neurons. wnv should be considered in cases of encephalitis in cetaceans.201121801643
emergence of attenuated west nile virus variants in texas, order to understand how west nile virus (wnv) has evolved since its introduction into north america, we have studied the genetic and phenotypic variation among wnv isolates collected in various areas during consecutive transmission seasons. the present report describes for the first time phenotypic changes occurring in the north american wnv population. several isolates collected in texas during 2003 display a small plaque (sp) and temperature sensitive (ts) phenotype, as well as reduced repl ...200415527859
use of testing for west nile virus and other the united states, the most commonly diagnosed arboviral disease is west nile virus (wnv) infection. diagnosis is made by detecting wnv igg or viral genomic sequences in serum or cerebrospinal fluid. to determine frequency of this testing in wnv-endemic areas, we examined the proportion of tests ordered for patients with meningitis and encephalitis at 9 hospitals in houston, texas, usa. we identified 751 patients (567 adults, 184 children), among whom 390 (52%) experienced illness onset durin ...201627537988
west nile virus activity--united states, october 6-12, 2004.during october 6-12, a total of 86 cases of human west nile virus (wnv) illness were reported from 18 states (arizona, florida, illinois, kansas, louisiana, michigan, minnesota, missouri, nevada, new jersey, new mexico, north dakota, ohio, oklahoma, pennsylvania, tennessee, texas, and utah).200415483530
characterization of west nile viruses isolated from captive american flamingoes (phoenicopterus ruber) in medellin, colombia.serum samples from a total of 71 healthy captive birds belonging to 18 species were collected in july of 2008 in medellin (colombia) and tested for flaviviruses. eighteen of 29 samples from american flamingoes (phoenicopterus ruber) were positive for west nile virus (wnv) by reverse transcription-polymerase chain reaction. selected positive samples were serially passaged and wnv was confirmed by immunofluorescence. two isolates (524/08, 9835/08) were characterized in vitro and in vivo. sequence ...201222802436
west nile virus activity--united states, september 29-october 5, 2004.during september 29-october 5, a total of 81 cases of human west nile virus (wnv) illness were reported from 18 states (alabama, arizona, arkansas, california, florida, georgia, illinois, iowa, kansas, kentucky, minnesota, missouri, ohio, oklahoma, pennsylvania, south dakota, texas, and virginia).200415470326
west nile virus, texas, usa, 2012.during the 2012 west nile virus outbreak in texas, usa, 1,868 cases were reported. male patients, persons >65 years of age, and minorities were at highest risk for neuroinvasive disease. fifty-three percent of counties reported a case; 48% of case-patients resided in 4 counties around dallas/fort worth. the economic cost was >$47.6 million.024210089
west nile virus activity--united states, august 11-17, 2004.during august 11-17, a total of 194 cases of human west nile virus (wnv) illness were reported from 17 states (alabama, arizona, california, colorado, florida, illinois, louisiana, maryland, minnesota, mississippi, missouri, new mexico, ohio, south dakota, texas, utah, and virginia).200415318160
west nile virus activity--united states, july 14-20, 2004.during the week of july 14-20, a total of 74 cases of human west nile virus (wnv) illness were reported from seven states (arizona, california, florida, new mexico, new york, south dakota, and texas).200415269701
molecular determinants of virulence of west nile virus in north america.west nile virus (wnv) is a mosquito-borne flavivirus that until very recently had not been found in the americas. in 1999, there was an outbreak of west nile encephalitis in new york and surrounding areas, involving 62 human cases, including 7 fatalities. the virus has subsequently become established in the united states of america (u.s.) with 4156 human cases, including 284 deaths, in 2002. the wnv strains found in the u.s. are members of "lineage i", a genetic grouping that includes viruses fr ...200415119761
limited evolution of west nile virus has occurred during its southwesterly spread in the united states.analysis of partial nucleotide sequences of nine west nile virus strains isolated in southeast texas during june-august 2002 revealed a maximum of 0.35% nucleotide variation from a new york 1999 strain. two sequence subtypes were identified that differed from each other by approximately 0.5%, suggesting multiple introductions of virus to this area. analysis of sequences from cloned pcr products for one strain revealed up to 0.6% divergence from the consensus sequence at the subpopulation level. ...200312758166
vector competence of three north american strains of aedes albopictus for west nile evaluate the potential for north american (na) aedes albopictus to transmit west nile virus (wn), mosquito strains derived from 3 na sources (frederick county, maryland, fred strain; cheverly, md, chev strain; chambers and liberty counties, texas, tamu strain) were tested. these strains were tested along with a previously tested strain from a hawaiian source (oahu strain). mosquitoes were fed on 2- to 3-day-old chickens previously inoculated with a new york strain (crow 397-99) of wn. all of ...200212542184
west nile virus infection among the homeless, houston, texas.among 397 homeless participants studied, the overall west nile virus (wnv) seroprevalence was 6.8%. risk factors for wnv infection included being homeless >1 year, spending >6 hours outside daily, regularly taking mosquito precautions, and current marijuana use. public health interventions need to be directed toward this high-risk population.200718257995
identification of hyperendemic foci of horses with west nile virus disease in 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.200818312137
clinical investigation of hospitalized human cases of west nile virus infection in houston, texas, 2002-2004.the objective of this study was to describe the clinical features of cases hospitalized with west nile virus (wnv) infections and identify clinical parameters that could potentially predict poor outcome (death). retrospective medical chart reviews were completed for 172 confirmed cases of wnv infection hospitalized in the houston, texas, metropolitan area between 2002 and 2004. of the 172 patients, 113 had encephalitis which resulted in 17 deaths, 47 had meningitis, and 12 had uncomplicated feve ...200818399781
genetic stasis of dominant west nile virus genotype, houston, texas.the accumulation and fixation of mutations in west nile virus (wnv) led to the emergence of a dominant genotype throughout north america. subsequent analysis of 44 isolates, including 19 new sequences, from houston, texas, suggests that wnv has reached relative genetic stasis at the local level in recent years.200717553276
juvenile dogs as potential sentinels for west nile virus surveillance.we conducted a study to determine whether juvenile stray dogs could be sentinels for west nile virus (wnv) surveillance. seroconversion was detected 6 weeks before the first reported human case. our findings provide evidence that dogs could be useful sentinels for monitoring areas for evidence of wnv during transmission seasons.200818399945
survey of mosquito fauna in lubbock county, texas.records of mosquito species occurring in lubbock county, tx, have not been reported since 1970. an updated mosquito survey was conducted as part of the west nile virus surveillance program conducted throughout lubbock county, tx from july 2002 through december 2004. a large number of species not previously recorded occurring in this area were collected, whereas several species historically occurring in the area were not collected during this survey. based upon the data from this study, dominant ...200818939702
fatal hemophagocytic lymphohistiocytosis associated with locally acquired dengue virus infection - new mexico and texas, 2012.dengue is caused by infection with any of four mosquito-transmitted dengue viruses (denv-1-4) and is characterized by fever, headache, myalgia, and leukopenia. hemophagocytic lymphohistiocytosis (hlh) is a potentially fatal hyperinflammatory syndrome that can be familial or acquired, and is characterized by persistent fever, pancytopenia, hepatosplenomegaly, and increased serum ferritin. acquired hlh is most frequently associated with epstein barr virus infection but also has been associated wit ...201424452132
environmental risk factors for equine west nile virus disease cases in texas.west nile virus (wnv) was first detected in the texas equine population during june 2002. infection has since spread rapidly across the state and become endemic in the equine population. environmental risk factors associated with equine wnv attack rates in texas counties during the period 2002 to 2004 were investigated. equine wnv attack rates were smoothed using an empirical bayesian model, because of the variability among county equine populations (range 46-9,517). risk factors investigated in ...200919031106
equine west nile virus disease occurrence and the normalized difference vegetation index.the association between the normalized difference vegetation index (ndvi) and periods of above- or below-average reported cases of equine west nile virus encephalomyelitis, reported in texas between 2002 and 2004, was investigated. a time-series of case reports, using a biweekly window, was constructed. because of the disparity in number of cases reported (1698, 672 and 101 in 2002, 2003 and 2004, respectively), data were standardized by calculating the number of cases reported during each biwee ...200919054585
multiple pathways to the attenuation of west nile virus in south-east texas in 2003.west nile virus (wnv) was first detected in texas in 2002. during 2003, several isolates exhibiting significant attenuation of mouse neuroinvasiveness, and in some cases a small plaque and temperature sensitive phenotype when compared to other north american wnv isolates, were obtained from birds and mosquitoes in south-east texas. to determine the attenuation markers of wnv, we have sequenced the genomes of three attenuated isolates and four temporally related virulent isolates and compared the ...201020580395
community-acquired meningitis in older adults: clinical features, etiology, and prognostic investigate the epidemiology and outcomes of community-acquired meningitis in older adults.201425370434
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, september 15-21, 2004.during september 15-21, a total of 218 cases of human west nile virus (wnv) illness were reported from 21 states (arizona, california, florida, illinois, indiana, kansas, maryland, michigan, minnesota, mississippi, missouri, nebraska, nevada, new mexico, north dakota, oklahoma, south dakota, texas, utah, wisconsin, and wyoming).200415385920
west nile virus activity--united states, july 28-august 3, 2004.during july 28-august 3, a total of 141 cases of human west nile virus (wnv) illness were reported from 11 states (alabama, arizona, california, colorado, florida, illinois, nevada, new york, north dakota, south dakota, and texas). during 2004, a total of 20 states have reported a total of 406 cases of human wnv illness to cdc through arbonet. of these, 247 (61%) were reported from arizona. a total of 226 (57%) of the 406 cases occurred in males; the median age of patients was 51 years (range: 1 ...200415295314
surveillance for acute insecticide-related illness associated with mosquito-control efforts--nine states, 1999-2002.ground and aerial applications of insecticides are used to control populations of adult mosquitoes, which spread such diseases as west nile virus--related illness, eastern equine encephalitis, and dengue fever. this report summarizes investigations of illnesses associated with exposures to insecticides used during 1999-2002 to control mosquito populations in nine states (arizona, california, florida, louisiana, michigan, new york, oregon, texas, and washington) (estimated 2000 population: 118 mi ...200312855943
survival analysis, long-term outcomes, and percentage of recovery up to 8 years post-infection among the houston west nile virus 2012, we witnessed a resurgence of west nile virus (wnv) in the united states, with the largest outbreak of human cases reported since 2003. wnv is now endemic and will continue to produce epidemics over time, therefore defining the long-term consequences of wnv infection is critical. over a period of eight years, we prospectively followed a cohort of 157 wnv-infected subjects in the houston metropolitan area to observe recovery over time and define the long-term clinical outcomes. we used su ...201425054656
proximity of residence to bodies of water and risk for west nile virus infection: a case-control study in houston, texas.west nile virus (wnv), a mosquito-borne virus, has clinically affected hundreds of residents in the houston metropolitan area since its introduction in 2002. this study aimed to determine if living within close proximity to a water source increases one's odds of infection with wnv. we identified 356 eligible wnv-positive cases and 356 controls using a population proportionate to size model with us census bureau data. we found that living near slow moving water sources was statistically associate ...201222315511
toscana meningoencephalitis: a comparison to other viral central nervous system infections.toscana virus (tosv) is an emerging pathogen causing central nervous system (cns) infection in mediterranean countries, mostly during summer season.201222867730
dynamic transmission of west nile virus across the united states-mexican border.confirmed clinical and veterinary cases of west nile virus (wnv) infection in mexico remain restricted to northern mexico, supporting a unidirectional transmission model from the us into mexico. full-length genomic sequencing of nine wnv isolates obtained from culex spp. mosquito pools in el paso, texas (n=7) and cuidad juarez, mexico (n=2) from 2005 to 2010 demonstrates the co-circulation of three independent genetic groups, two of which belong to the southwestern (sw/wn03) genotype and the oth ...201223141421
quantifying the potential pathways and locations of rift valley fever virus entry into the united states.the global invasion of west nile virus, chikungunya virus and zika virus in the past two decades suggests an increasing rate of mosquito-borne virus (arbovirus) dispersal. rift valley fever virus (rvfv) is an arbovirus identified as a high-consequence threat to the united states (usa) because of the severe economic and health consequences associated with disease. numerous studies demonstrate that the usa is receptive to rvfv transmission based on the widespread presence of competent mosquito spe ...201728191786
west nile virus activity--united states, september 5-11, 2002, and texas, january 1-september 9, 2002.this report summarizes west nile virus (wnv) surveillance data reported to cdc through arbonet and by states and other jurisdictions as of 7:30 a.m. mountain daylight time, september 11, 2002.200212269471
efficacy of deltagard(®), fyfanon(®), and evoluer™ 31-66 against culex quinquefasciatus in harris county, texas.the comparative efficacy of ultra-low volume applications of deltamethrin, permethrin, and malathion against specific adult populations of culex quinquefasciatus , a primary regional vector of saint louis encephalitis and west nile virus, using field cage tests is described. at labeled application rates, the estimated mass median diameters for fyfanon(®), evoluer™, and deltagard(®) were 18.32, 19.24, and 17.44 μm, respectively. no significant differences (p ≥ 0.01) in mean percent control were o ...201728388328
2014: a record-breaking year for west nile virus positive mosquito pools in harris county and the city of houston, the 14 years since the emergence of west nile virus (wnv) in harris county and the city of houston, texas, the number of mosquitoes infected with the virus has fluctuated with several high and low count years. during this 14-year period, mosquito surveillance operational areas in harris county were expanded from 248 to 268 and the distribution of the virus activity in mosquitoes varied from year to year. operational areas with wnv infected mosquitoes increased from 137 in 2002 to 197 in 2006, ...201627613203
Reduced avian virulence and viremia of West Nile virus isolates from Mexico and Texas.A West Nile virus (WNV) isolate from Mexico (TM171-03) and BIRD1153, a unique genotype from Texas, have exhibited reduced murine neuroinvasive phenotypes. To determine if murine neuroinvasive capacity equates to avian virulence potential, American crow (Corvus brachyrhynchos) and house sparrows (Passer domesticus) were experimentally inoculated with representative murine neuroinvasive/non-neuroinvasive strains. In both avian species, a plaque variant from Mexico that was E-glycosylation competen ...201121976584
west nile virus infection in kidney and pancreas transplant recipients in the dallas-fort worth metroplex during the 2012 texas 2012, the united states experienced one of its worst west nile virus (wnv) epidemics, reporting 5,387 human cases and final death toll of 243. texas was at the epicenter of the outbreak, with 1,875 reported cases and 89 deaths that year. the texas outbreak centered mainly in the dallas-fort worth area where 30 deaths were reported. we report three cases of severe wnv infection complicated by meningoencephalitis in our organ transplant population.201424827765
clinical features of west nile virus epidemic in dallas, texas, 2012, texas has reported the highest number of west nile virus (wnv) cases in the united states to the centers for disease control and prevention. in this report, we conducted a retrospective chart review of 57 patients with wnv disease and analyzed the clinical features of these patients. our results revealed that 25 (44%) patients were diagnosed with west nile fever and 32 (56%) with west nile neuroinvasive disease (wnnd). the median age for patients with wnnd was 54.5 years, and those with ...201424316017
prevalence of chronic kidney disease and progression of disease over time among patients enrolled in the houston west nile virus experimental models of west nile virus (wnv) infection, animals develop chronic kidney infection with histopathological changes in the kidney up to 8-months post-infection. however, the long term pathologic effects of acute infection in humans are largely unknown. the purpose of this study was to assess renal outcomes following wnv infection, specifically the development of chronic kidney disease (ckd).201222792293
west nile virus infection incidence based on donated blood samples and neuroinvasive disease reports, northern texas, usa, 2012.during the 2012 outbreak of west nile virus in the united states, approximately one third of the cases were in texas. of those, about half occurred in northern texas. models based on infected blood donors and persons with neuroinvasive disease showed, respectively, that ≈0.72% and 1.98% of persons in northern texas became infected.025812045
west nile virus infection among humans, texas, usa, 2002-2011.we conducted an epidemiologic analysis to document west nile virus infections among humans in texas, usa, during 2002-2011. west nile virus has become endemic to texas; the number of reported cases increased every 3 years. risk for infection was greatest in rural northwestern texas, where culex tarsalis mosquitoes are the predominant mosquito species.023260575
continued evolution of west nile virus, houston, texas, usa, 2002-2012.we investigated the genetics and evolution of west nile virus (wnv) since initial detection in the united states in 1999 on the basis of continual surveillance studies in the houston, texas, usa, metropolitan area (harris county) as a surrogate model for wnv evolution on a national scale. full-length genomic sequencing of 14 novel 2010-2012 wnv isolates collected from resident birds in harris county demonstrates emergence of 4 independent genetic groups distinct from historical strains circulati ...023965756
sequence analyses of 2012 west nile virus isolates from texas fail to associate viral genetic factors with outbreak 2012, texas experienced the largest outbreak of human west nile encephalitis (wne) since the introduction of west nile virus (wnv) in 2002. despite the large number of wnv infections, data indicated the rate of reported wne among human cases was no higher than in previous years. to determine whether the increase in wnv human cases could have been caused by viral genetic changes, the complete genomes of 17 isolates made from mosquito pools in dallas and montgomery counties in 2012 were sequenc ...201323817333
a temperature-limited assessment of the risk of rift valley fever transmission and establishment in the continental united states of america.the rapid spread of west nile virus across north america after its introduction in 1999 highlights the potential for foreign arboviruses to become established in the united states of america. of particular concern is rift valley fever virus (rvfv), which has been responsible for multiple african epidemics resulting in death of both humans and livestock, as well as major economic disruption due to livestock loss and trade restrictions. modern globalization, travel, and commerce allow viruses to e ...201222639118
incidence of west nile virus infection in the dallas-fort worth metropolitan area during the 2012 epidemic.the 2012 west nile virus (wnv) epidemic was the largest since 2003 and the north texas region was the most heavily impacted. we conducted a serosurvey of blood donors from four counties in the dallas-fort worth area to characterize the epidemic. blood donor specimens collected in november 2012 were tested for wnv-specific antibodies. donors positive for wnv-specific igg, igm, and neutralizing antibodies were considered to have been infected in 2012. this number was adjusted using a multi-step pr ...201626829991
persistence of detectable immunoglobulin m antibodies up to 8 years after infection with west nile houston, we have been monitoring the immune response to west nile virus (wnv) infection in a large cohort of study participants since 2002. using enzyme-linked immunosorbent assay techniques, serum from 163 participants was tested for the presence of anti-wnv immunoglobulin m (igm) and igg antibodies. we found that 42%, 34%, and 23% of study participants had either positive or equivocal results when tested for anti-wnv igm antibodies approximately 1, 6, and 8 years post-infection, respectivel ...201324062481
findings of long-term depression up to 8 years post infection from west nile examine the psychological sequelae following west nile virus (wnv) infection among a large cohort of participants over an 8-year period.201223929558
the 2012 west nile encephalitis epidemic in dallas, texas.after progressive declines over recent years, in 2012 west nile virus epidemics resurged nationwide, with the greatest number of cases centered in dallas county, texas.201323860988
preliminary disease surveillance in west texas quail (galliformes: odontophoridae) populations.northern bobwhite (colinus virginianus) and scaled quail (callipepla squamata) occur throughout northwestern texas and overall population numbers have been declining for the past 30 yr. this decline has been attributed to habitat loss associated with intensive agricultural practices. we propose that disease may be a contributing factor to decline. our findings suggest that west nile virus (wnv) infection may be common in wild quail populations on the rolling plains of northwestern texas. serum s ...201323568922
effect of aerial insecticide spraying on west nile virus disease--north-central texas, 2012.during 2012, four north-central texas counties experienced high west nile virus (wnv) disease incidence. aerial insecticide spraying was conducted in two counties. to evaluate the effect of spraying on wnv disease, we calculated incidence rate ratios (irrs) in treated and untreated areas by comparing incidence before and after spraying; for unsprayed areas, before and after periods were defined by using dates from a corresponding sprayed area. in treated areas, wnv neuroinvasive disease incidenc ...201424778196
texas records worst outbreak of west nile virus on record. 201222956635
controlling urban epidemics of west nile virus infection. 201222922679
us hit by massive west nile virus outbreak centred around texas. 201222915691
culex flavivirus and west nile virus in culex quinquefasciatus populations in the southeastern united states.little is known of the interactions between insect-only flaviviruses and other arboviruses in their mosquito hosts, or the potential public health significance of these associations. the specific aims of this study were to describe the geographic distribution, prevalence, and seasonal infection rates of culex flavivirus (cxfv) and west nile virus (wnv) in culex quinquefasciatus say in the southeastern united states, investigate the potential association between cxfv and wnv prevalence in cx. qui ...201222308785
perspective: one health: a compelling health has been defined as "the collaborative effort of multiple disciplines--working locally, nationally, and globally--to attain optimal health for people, animals, plants, and our environment." the broadly based one health movement includes domains as diverse as agricultural and animal science, environmental science, climatology, veterinary medicine, human medicine, and public health. one health, previously espoused by virchow, osler, and other pioneers in medical education, is not a new ...201323165268
[a new form of west nile virus. west nile virus in texas]. 201222988731
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
genetic variation associated with mammalian feeding in culex pipiens from a west nile virus epidemic region in chicago, illinois.mosquitoes of the culex pipiens complex are important vectors of west nile virus in the united states. we examined the genetic variations of cx. pipiens mosquitoes from chicago, illinois that were determined to be principally ornithophilic but exhibited a relatively higher inclination for mammalian hosts including humans. microsatellite analysis of 10 polymorphic markers was performed on 346 engorged cx. pipiens specimens with identified avian or mammalian blood meals. our results indicated that ...200919281434
use of laboratory reports as predictors of west nile virus disease cases, texas, 2008-2012.we evaluated laboratory reports as early indicators of west nile virus (wnv) disease cases in texas. we compared wnv laboratory results in the national electronic disease surveillance system base system (nbs) to wnv disease cases reported to the state health department from 2008 to 2012. we calculated sensitivity and positive predictive value (ppv) of nbs reports, estimated the number of disease cases expected per laboratory report, and determined lead and lag times. the sensitivity and ppv of n ...201524762928
west nile virus outbreak in houston and harris county, texas, usa, 2014.since 2002, west nile virus (wnv) has been detected every year in houston and the surrounding harris county, texas. in 2014, the largest wnv outbreak to date occurred, comprising 139 cases and causing 2 deaths. additionally, 1,286 wnv-positive mosquito pools were confirmed, the most reported in a single mosquito season.201728726615
the role of birds in arboviral disease surveillance in harris county and the city of houston, texas.avian arboviral surveillance is an integral part of any disease-based integrated mosquito control program. the harris county public health mosquito and vector control division has performed arboviral surveillance in the wild birds of harris county and the city of houston since 1965. blood samples from live trapped birds were tested for arboviral antibodies to west nile virus (wnv), st. louis encephalitis, eastern equine encephalitis, and western equine encephalitis. a dead bird surveillance prog ...201728511269
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