| west nile virus activity in the united states, 2001. | west nile virus (wnv) first appeared in the naive environment of the western hemisphere in 1999 in new york. genetic analysis determined that the virus was introduced into the united states from the mediterranean basin. this review discusses the spread of the virus in 2001 from the initial focus in queens, new york, to widespread activity in the eastern and midwestern united states. it concentrates on viral ecology, epizootiology, pathology, prediction, and prevention. research questions to furt ... | 2001 | 11792062 |
| update: surveillance for west nile virus in overwintering mosquitoes--new york, 2000. | following the 1999 west nile encephalitis outbreak in new york, guidelines were developed to direct surveillance, prevention, and control efforts in the eastern united states. as recommended in the guidelines, the new york city and new york state departments of health developed comprehensive west nile virus (wnv) surveillance and control programs, which included collecting overwintering culex mosquitoes to determine whether wnv might persist throughout the winter and initiate a zoonotic transmis ... | 2000 | 11795498 |
| sentinel chickens as a surveillance tool for west nile virus in new york city, 2000. | | 2001 | 11797795 |
| west nile virus human surveillance in nassau county, new york: 1999-2000. | | 2001 | 11797796 |
| vector competence of three north american strains of aedes albopictus for west nile virus. | to 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 ... | 2002 | 12542184 |
| comparison of vero cell plaque assay, taqman reverse transcriptase polymerase chain reaction rna assay, and vectest antigen assay for detection of west nile virus in field-collected mosquitoes. | mosquitoes collected during the epidemic of west nile virus (wn) in staten island, ny, during 2000 were identified to species, grouped into pools of up to 50 individuals, and tested for the presence of wn by using taqman reverse transcriptase polymerase chain reaction (rt-pcr) to detect west nile viral rna, vero cell plaque assay to detect infectious virus, and vectest wnv/sle antigen panel assay. a total of 10,866 specimens was tested in 801 pools. analysis of results indicated that taqman rt-p ... | 2002 | 12542186 |
| serologic evidence for west nile virus infection in birds in staten island, new york, after an outbreak in 2000. | after an outbreak of west nile virus (wnv) infections in people, horses, and wildlife in staten island, ny, during the summer of 2000, we surveyed the bird population of the island for evidence of infection. neutralizing antibodies were detected in 59 of 257 (23.0%) resident birds and none of 96 transient (migrating) birds sampled in early october. species with the greatest seroprevalence were northern cardinal (cardinalis cardinalis) (69.2%) and rock dove (columba livia) (54.5%). house sparrows ... | 2001 | 12653147 |
| complete genome sequences and phylogenetic analysis of west nile virus strains isolated from the united states, europe, and the middle east. | the complete nucleotide sequences of eight west nile (wn) virus strains (egypt 1951, romania 1996-mq, italy 1998-equine, new york 1999-equine, md 2000-crow265, nj 2000mq5488, ny 2000-grouse3282, and ny 2000-crow3356) were determined. phylogenetic trees were constructed from the aligned nucleotide sequences of these eight viruses along with all other previously published complete wn virus genome sequences. the phylogenetic trees revealed the presence of two genetic lineages of wn viruses. lineage ... | 2002 | 12093177 |
| host-feeding habits of culex and other mosquitoes (diptera: culicidae) in the borough of queens in new york city, with characters and techniques for identification of culex mosquitoes. | the host-feeding patterns of mosquitoes (n = 247) collected in the borough of queens in new york city in july and august 2000 were investigated using an indirect elisa and a polymerase chain reaction (pcr)-heteroduplex assay. culex pipiens l. and cx. restuans theobald fed primarily on birds, and their feeding habits support their implication as enzootic vectors of west nile virus. culex salinarius coquillett and coquillettidia perturbans (walker) fed mainly on mammals, with fewer blood meals tak ... | 2002 | 12349862 |
| first isolation of west nile virus from a patient with encephalitis in the united states. | west nile virus (wnv) was isolated from a patient who developed encephalitis while undergoing treatment with chop (cyclophosphamide, hydroxydoxorubicin, vincristine [oncovin], predisone) and rituximab for a non-hodgkin b-cell lymphoma. both standard reverse transcription-polymerase chain reaction (rt-pcr) and taqman rt-pcr established the diagnosis of wnv infection from cerebrospinal fluid (csf). several whole blood samples and one serum sample underwent further testing. csf and serum samples we ... | 2002 | 12498649 |
| west nile virus encephalitis in the united states. | west nile virus appeared in new york city in 1999 and has subsequently spread over the eastern united states. the mode of transport across the atlantic ocean is unknown. during the past decade, encephalitis has been a more prominent feature of west nile virus infection in europe, the middle east, and the united states, suggesting the emergence of more neurovirulent strains. the rapid spread of the virus and more serious disease caused by the virus have spurred vaccine development. | 2002 | 12359102 |
| detection of west nile virus-infected mosquitoes and seropositive juvenile birds in the vicinity of virus-positive dead birds. | mosquitoes and wild birds were collected from three sites near locations in the new york city metropolitan area where single, west nile (wn) virus-positive dead birds were found early in the 2000 transmission season. the mosquitoes were tested for the presence of infectious virus with a vero cell culture assay and for wn viral rna by using reverse transcriptase-polymerase chain reaction (rt-pcr) protocols. serum samples from wild birds were tested for the presence of neutralizing antibodies agai ... | 2002 | 12479550 |
| 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. ... | 2003 | 12758166 |
| larvicide debate marks start of another west nile virus summer. | | 2003 | 12771083 |
| identifying west nile virus risk areas: the dynamic continuous-area space-time system. | the dynamic continuous-area space-time (dycast) system was developed to identify and prospectively monitor high-risk areas for west nile virus in new york, new york (new york city). the system is based on a geographic model that uses a localized knox test to capture the nonrandom space-time interaction of dead birds, as an indicator of an intense west nile virus amplification cycle, within a 1.5-mile (2.41-km) buffer area and 21-day moving window. the knox analysis is implemented as an interpola ... | 2003 | 12727678 |
| dead bird clusters as an early warning system for west nile virus activity. | an early warning system for west nile virus (wnv) outbreaks could provide a basis for targeted public education and surveillance activities as well as more timely larval and adult mosquito control. we adapted the spatial scan statistic for prospective detection of infectious disease outbreaks, applied the results to data on dead birds reported from new york city in 2000, and reviewed its utility in providing an early warning of wnv activity in 2001. prospective geographic cluster analysis of dea ... | 2003 | 12781002 |
| from the centers for disease control and prevention. intrauterine west nile virus infection--new york, 2002. | | 2003 | 12532964 |
| public health and the media: the challenge now faced by bioterrorism. | | 2002 | 11937610 |
| west nile virus: uganda, 1937, to new york city, 1999. | west nile virus, first isolated in 1937, is among the earliest arthropod-borne viruses discovered by humans. its broad geographical distribution, not uncommon infection of humans, transmission by mosquitoes, and association with wild birds as enzootic hosts were well documented by the mid-1960s. however, west nile virus was not considered to be a significant human pathogen because most infections appeared to result in asymptomatic or only mild febrile disease. several epidemics had been document ... | 2001 | 11797781 |
| discrimination of west nile virus and japanese encephalitis virus strains using rt-pcr rflp analysis. | west nile (wn) virus is a mosquito-borne flavivirus that induces lethal encephalitis in humans and horses. since an outbreak of wn encephalitis in humans and horses occurred in new york city in late august 1999, the possibility exists that wn virus will invade regions that have close links with the united states, such as japan. we developed a genetic diagnostic method that discriminates between strains of wn virus and japanese encephalitis (je) virus. the method involves rt-pcr restriction fragm ... | 2003 | 12906104 |
| intrauterine west nile virus infection--new york, 2002. | west nile virus (wnv), a mosquito-borne flavivirus and human neuropathogen, is epidemic in the united states. in 2002, newly recognized mechanisms of person-to-person wnv transmission were described, including possible transmission from mother to infant through breast milk. wnv has not been previously associated with intrauterine infection or adverse birth outcomes. this report describes a case of transplacental wnv transmission. pregnant women should take precautions to reduce their risk for wn ... | 2002 | 12537289 |
| arbovirus surveillance in rhode island: assessing potential ecologic and climatic correlates. | during 1995-2000, mosquitoes were collected from sites throughout rhode island and tested for the presence of arboviruses. mosquito trapping was done weekly from june to october with co2-baited light traps. in all, 186,537 mosquitoes belonging to 7 different genera were collected, of which coquillettidia perturbans was most abundant. a total of 6,434 pools were processed for arbovirus isolation, from which 193 arboviral isolations were made. these included 109 highlands j, 71 eastern equine ence ... | 2003 | 14524538 |
| host feeding patterns of established and potential mosquito vectors of west nile virus in the eastern united states. | an important variable in determining the vectorial capacity of mosquito species for arthropod-borne infections is the degree of contact of the vector and the vertebrate reservoir. this parameter can be estimated by examining the host-feeding habits of vectors. serological and polymerase chain reaction based methods have been used to study the host-feedings patterns of 21 mosquito species from new york, new jersey, and tennessee, 19 of which previously have been found infected with west nile viru ... | 2004 | 15018775 |
| aliens on the shores. | | 2003 | 12776170 |
| spinal cord neuropathology in human west nile virus infection. | during the 1999 new york city west nile virus (wnv) outbreak, 4 patients with profound muscle weakness, attributed to guillain-barré syndrome, were autopsied. these cases were the first deaths caused by wnv, a flavivirus, to be reported in the united states. the patients' brains had signs of mild viral encephalitis; spinal cords were not examined. during the 2002 national epidemic, several patients in mississippi had acute flaccid paralysis. electrophysiologic studies localized the lesions to th ... | 2004 | 15086282 |
| 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 ... | 2004 | 15119761 |
| early season crow mortality as a sentinel for west nile virus disease in humans, northeastern united states. | the 1999 new york epidemic of human west nile virus (wn) encephalitis and meningitis was preceded by a crow die-off also caused by wn infection. as one component of the subsequently developed national surveillance system, crow mortality data were collected to detect wn activity before humans might become infected. however, predicting areas at risk for human wn disease likely requires assessment of multiple factors, including the intensity and timing of crow epizootics. to identify early season m ... | 2002 | 12737544 |
| spatial analysis of west nile virus: rapid risk assessment of an introduced vector-borne zoonosis. | the distribution of human risk for west nile virus was determined by spatial analysis of the initial case distribution for the new york city area in 1999 using remote sensing and geographic information system technologies. cluster analysis revealed the presence of a statistically significant grouping of cases, which also indicates the area of probable virus introduction. within the cluster, habitat suitability for potentially infective adult mosquitoes was measured by the amount of vegetation co ... | 2002 | 12737545 |
| 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 ... | 2003 | 12855943 |
| vector competence of culex tarsalis from orange county, california, for west nile virus. | to evaluate the vector competence of culex tarsalis coquillett for west nile virus (wn), females reared from larvae collected in huntington beach, orange county, ca, were fed on 2-3-day-old chickens previously inoculated with a new york strain (crow 397-99) of wn. the cx. tarsalis mosquitoes were efficient laboratory vectors of wn, with estimated transmission rates of 81% and 91% for mosquitoes that ingested 10(6.5) or 10(7.3) plaque-forming units of wn/ml of blood, respectively. based on effici ... | 2002 | 12737548 |
| west nile virus: a primer for infection control professionals. | in 1999, an outbreak of human west nile encephalitis occurred in new york city. during the outbreak, 62 cases of human west nile virus (wnv) infection were diagnosed, with 7 deaths. this was the first time that human wnv infections were detected in the western hemisphere. by 2002, the total number of human cases of wnv that year alone reached 4156, with 284 fatalities. in addition, investigations have shown that wnv can be acquired through organ transplantation, blood transfusion, breast milk, t ... | 2004 | 15057202 |
| pesticide spraying for west nile virus control and emergency department asthma visits in new york city, 2000. | pyrethroid pesticides were applied via ground spraying to residential neighborhoods in new york city during july-september 2000 to control mosquito vectors of west nile virus (wnv). case reports link pyrethroid exposure to asthma exacerbations, but population-level effects on asthma from large-scale mosquito control programs have not been assessed. we conducted this analysis to determine whether widespread urban pyrethroid pesticide use was associated with increased rates of emergency department ... | 2004 | 15289164 |
| west nile virus infection. | the epidemiology, virology, and transmission of west nile virus (wnv) are reviewed, and the clinical features, diagnosis, and treatment of wnv infection are examined. | 2004 | 15259752 |
| west nile virus antibodies in bats from new jersey and new york. | eighty-three serum samples were obtained from big brown (eptesicus fuscus), little brown (myotis lucifugus), and northern long-eared (myotis septentriotalis) bats (chiroptera: vespertilionidae), from new jersey and new york (usa) between july and october 2002. samples were analyzed for neutralizing antibodies to west nile virus (wnv) and st. louis encephalitis (sle) virus. one little brown bat and one northern long-eared bat tested positive for wnv neutralizing antibodies. no bats had antibodies ... | 2004 | 15362837 |
| west nile virus in the united states: an update on an emerging infectious disease. | west nile virus is a mosquito-borne flavivirus and human neuropathogen. since the virus was recognized in new york city in 1999, it has spread rapidly across the united states, with human disease documented in 39 states and the district of columbia. west nile virus can cause a broad range of clinical syndromes, including fever, meningitis, encephalitis, and a flaccid paralysis characteristic of a poliomyelitis-like syndrome. approximately one in 150 infections results in severe neurologic illnes ... | 2003 | 12952382 |
| 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 ... | 2004 | 15295314 |
| long-term prognosis for clinical west nile virus infection. | relatively little is known about the long-term prognosis for patients with clinical west nile virus (wnv) infection. we conducted a study to describe the recovery of new york city residents infected during the 1999 wnv encephalitis outbreak. patients were interviewed by telephone on self-perceived health outcomes 6, 12, and 18 months after wnv illness onset. at 12 months, the prevalence of physical, functional, and cognitive symptoms was significantly higher than that at baseline, including musc ... | 2004 | 15496241 |
| 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). | 2004 | 15514584 |
| 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). | 2004 | 15269701 |
| emergence of attenuated west nile virus variants in texas, 2003. | in 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 ... | 2004 | 15527859 |
| different chemokine expression in lethal and non-lethal murine west nile virus infection. | west nile (wn) virus is a mosquito-borne flavivirus that can cause lethal encephalitis in humans and horses. the wn virus endemic in new york city (ny) in 1999 caused large-scale mortality of wild birds that was not evident in endemic areas in other parts of the world, and the pathogenesis of the wn virus strain isolated in ny (ny strain) appears to differ from that of previously isolated strains. however, the pathogenesis of ny strain infection remains unclear. this study examined cc (rantes/cc ... | 2004 | 15368509 |
| 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). | 2004 | 15371969 |
| poor replication of west nile virus (new york 1999 strain) in three reptilian and one amphibian species. | because west nile (wn) virus primarily cycles between mosquitoes and birds, north american reptiles and amphibians have not been evaluated as reservoir hosts of this virus. we infected three species of reptiles and one species of amphibian: iguana iguana (green iguana), thamnophis sirtalis sirtalis (florida garter snake), trachymes scripta elegans (red-ear slider), and rana catesbeiana (north american bullfrog). after inoculation with wn virus, some of the green iguanas, bullfrogs, and garter sn ... | 2003 | 14628941 |
| vectest as diagnostic and surveillance tool for west nile virus in dead birds. | the vectest antigen-capture assay for west nile virus was performed on oral and tissue swabs from dead birds in new york state from april 2003 through july 2004. results were compared with those from real-time reverse transcriptase-polymerase chain reaction of kidney or brain. oral vectest sensitivity is adequate for surveillance in american crows (corvus brachyrhynchos) (87%), blue jays (cyanocitta cristata) (80%), and house sparrows (passer domesticus) (76%). oral vectest performed well for sm ... | 2004 | 15663856 |
| genetic and phenotypic variation of west nile virus in new york, 2000-2003. | west nile virus (wnv) strains circulating during the first five years of wnv transmission in new york were collected, partial nucleotide sequences were determined, and in vitro and in vivo phenotypic analyses of selected strains were undertaken to determine whether observed increases in the intensity of enzootic and epidemic transmission in new york state during 2002 and 2003 were associated with viral genetic changes. functionally diverse regions of the wnv genome were also compared to determin ... | 2004 | 15516648 |
| serologic evidence of exposure of wild mammals to flaviviruses in the central and eastern united states. | serosurveys were conducted to obtain flavivirus and west nile virus (wnv) seroprevalence data from mammals. sera from 513 small- and medium-sized mammals collected during late summer and fall 2003 from colorado, louisiana, new york, ohio, and pennsylvania were screened for flavivirus-specific antibodies. sera samples containing antibody to flaviviruses were screened for wnv-specific antibodies by epitope-blocking enzyme-linked immunosorbent assays and confirmed with plaque reduction neutralizati ... | 2005 | 15891139 |
| west nile virus: epidemiology, clinical presentation, diagnosis, and prevention. | west nile virus was recognized in the united states for the first time in 1999, when it caused an epidemic of encephalitis and meningitis in new york city, ny. since then, the disease has been steadily moving westward, and human cases were recognized in 39 states and the district of columbia in 2002. the infection is caused by a flavivirus that is transmitted from birds to humans through the bite of culicine mosquitoes. most infections are mild, with symptoms primarily being fever, headache, and ... | 2003 | 12962168 |
| migratory birds and west nile virus. | west nile virus was first recorded in the new world during august 1999 in new york city. aetiology of the disease in the old world indicated birds as the likely introductory and amplifying hosts with ornithophilous mosquitoes, e.g. culex pipiens, as the principal vectors. speculation regarding likely agents for movement of the virus in its new environment focused on migratory birds, but evidence to date is equivocal. while spread of the disease has been fairly rapid, at a rate of roughly 70 km a ... | 2003 | 12675936 |
| the west nile virus: a lesson in emerging infections. | since its identification in new york city in 1999, the west nile virus has spread to 45 states and caused human infections in at least 44 states. west nile virus is difficult to correctly diagnose without a high level of clinical suspicion and can cause severe debilitation or death in those with the most severe symptoms. this paper reviews the epidemiology, surveillance, prevention, clinical features, diagnosis, and treatment of this important emerging infection. lessons learned from west nile v ... | 2004 | 15228065 |
| genetic variation in west nile virus from naturally infected mosquitoes and birds suggests quasispecies structure and strong purifying selection. | intrahost genetic diversity was analysed in naturally infected mosquitoes and birds to determine whether west nile virus (wnv) exists in nature as a quasispecies and to quantify selective pressures within and between hosts. wnv was sampled from ten infected birds and ten infected mosquito pools collected on long island, ny, usa, during the peak of the 2003 wnv transmission season. a 1938 nt fragment comprising the 3' 1159 nt of the wnv envelope (e) coding region and the 5' 779 nt of the non-stru ... | 2005 | 16033965 |
| the effect of pesticide spraying on the rate and severity of ed asthma. | we report on the incidence of emergency department (ed) asthma presentations and admissions to the lincoln hospital, located in the south bronx of new york city, during the 1999 eradication program of the mosquito vector for west nile virus. spraying of malathion and resmethrin occurred in the hospital's geographic area over 4 days in september 1999. during that time, 1318 pediatric and adult patients were seen in the ed for asthma-related symptoms. of these, 222 (16.8%) were hospitalized. emerg ... | 2005 | 16032612 |
| patterns of west nile virus infection in ohio blue jays: implications for initiation of the annual cycle. | west nile virus (wnv) was first detected in north america in new york city in 1999 and rapidly moved westward. understanding the mechanisms by which the amplification cycle is reinitiated each year increases our ability to predict epizootics and geographic expansion of the disease. such understanding is enhanced by knowledge of the patterns of infection in the vertebrate reservoir hosts. blue jays (cyanocitta cristata) may serve as reservoir hosts for wnv. we examined the influence of age and da ... | 2004 | 15155993 |
| west nile virus and north america: an unfolding story. | before the introduction of the west nile virus (wnv) into the united states of america (usa) in 1999, conditions in north america were ideal for an arboviral epidemic. such factors as the large, susceptible and non-immune animal and human populations, the presence of competent vectors, increasing international travel and commerce, existing methods for rapid dissemination and an ill-prepared animal and public health infrastructure all combined to create the essential elements for a severe animal ... | 2004 | 15702719 |
| insecticide resistance in culex pipiens from new york. | insecticides are the primary means to control culex pipiens, an enzootic vector of west nile virus, in the usa. to better understand how the evolution of resistance might impact control of this insect, we investigated the levels of resistance in populations collected from 2 metropolitan areas (albany and syracuse, ny) to 4 larvicides (methoprene, phenothrin, bacillus sphaericus [bs], and bacillus thuringiensis israelensis [bti]) and 1 adulticide (phenothrin) registered for mosquito control in ne ... | 2005 | 16252522 |
| epidemic west nile virus encephalomyelitis: a temperature-dependent, spatial model of disease dynamics. | since first being detected in new york in 1999, west nile virus (wnv) has spread throughout the united states and more than 20,000 cases of equine wnv encephalomyelitis have been reported. a spatial model of disease occurrence was developed, using data from an outbreak of serologically confirmed disease in an unvaccinated population of horses at 108 locations in northern indiana between 3 august and 17 october 2002. daily maximum temperature data were recorded at meteorological stations surround ... | 2005 | 16112761 |
| west nile virus: legal responses that further environmental health. | | 2005 | 16121486 |
| experimental and natural infection of north american bats with west nile virus. | big brown (eptesicus fuscus) and mexican free-tailed (tadarida brasiliensis) bats were inoculated with the new york 99 strain of west nile virus to assess their potential to serve as amplifying hosts and determine the clinical effect of infection. groups of three or four bats were bled at daily intervals between 1 and 6 days after inoculation to determine the pattern of viremia. beginning 2 days after inoculation, virus was isolated each day from one or more e. fuscus bats, in titers ranging fro ... | 2005 | 16103624 |
| west nile virus activity--united states, january 1-december 1, 2005. | west nile virus (wnv) is the leading cause of arboviral encephalitis in the united states. originally discovered in africa in 1937, wnv was first detected in the western hemisphere in 1999 in new york city. since then it has caused seasonal epidemics of febrile illness and severe neurologic disease. during january 1-december 1, 2005, a total of 2,744 cases of wnv disease in humans were reported in the united states, an increase from 2,359 during the same period in 2004. a total of 1,165 cases we ... | 2005 | 16357821 |
| assessing capacity for surveillance, prevention, and control of west nile virus infection--united states, 1999 and 2004. | indigenous human disease caused by west nile virus (wnv) was first identified in the united states in august 1999 in the greater new york city area. by the end of 2004, human wnv disease had been reported in all states except washington, hawaii, and alaska, and wnv transmission to humans had been documented by five routes: mosquito bites (principally from culex spp.), blood transfusions, organ transplantation, transplacental transfer, and breastfeeding. during 1999-2005, a total of 19,525 cases ... | 2006 | 16484978 |
| culex restuans (diptera: culicidae) relative abundance and vector competence for west nile virus. | the abundance and vector competence of culex restuans theobald and culex pipiens l. were compared to determine the relative importance of these species as west nile virus (wnv) vectors in the northeastern united states. abundance was estimated from egg raft collections at 12 sites in albany, suffolk, and richmond counties, new york, during july, august, and september 2002 and 2003. cx. restuans was more abundant than cx. pipiens in both urban and rural areas, comprising 86% of 1,623 egg rafts co ... | 2005 | 16363169 |
| west nile virus: epidemiology and clinical features of an emerging epidemic in the united states. | west nile virus (wnv) was first detected in north america in 1999 during an outbreak of encephalitis in new york city. since then the virus has spread across north america and into canada, latin america, and the caribbean. the largest epidemics of neuroinvasive wnv disease ever reported occurred in the united states in 2002 and 2003. this paper reviews new information on the epidemiology and clinical aspects of wnv disease derived from greatly expanded surveillance and research on wnv during the ... | 2006 | 16409144 |
| sentinel pigeon surveillance for west nile virus by using lard-can traps at differing elevations and canopy cover classes. | sentinel pigeons, columba livia, were installed in lard-can traps at heights of 1.5 m and 7.6-9.1 m within differing canopy cover classes in new york city. adult mosquitoes were collected weekly from july to october 2002, as were serum samples from each pigeon. culex pipiens l. and culex restuans theobald comprised 97% of mosquitoes collected and were most numerous in canopy-level, forested traps. the west nile virus (family flaviviridae, genus flavivirus, wnv) seroconversion rate was significan ... | 2005 | 16465746 |
| discovering spatio-temporal models of the spread of west nile virus. | emerging infectious diseases are characterized by complex interactions among disease agents, vectors, wildlife, humans, and the environment. since the appearance of west nile virus (wnv) in new york city in 1999, it has infected over 8,000 people in the united states, resulting in several hundred deaths in 46 contiguous states. the virus is transmitted by mosquitoes and maintained in various bird reservoir hosts. its unexpected introduction, high morbidity, and rapid spread have left public heal ... | 2006 | 16573630 |
| pre-west nile virus outbreak: perceptions and practices to prevent mosquito bites and viral encephalitis in the united states. | mosquitoes can transmit over 100 of the viruses that can cause encephalitis, meningitis, and hemorrhagic disease in humans (chin 2000; gubler 1996; monath 1989). while much is known about the ecology, epidemiology, and clinical manifestations of the arboviral encephalitides (campbell et al. 2002; centers for disease control and prevention 1997; gubler 1998; hayes 1989; hubálek and halouzka 1999), little empirical research exists regarding the u.s. population's knowledge of mosquitoes and arbovir ... | 2003 | 14733669 |
| west nile virus in the united states (1999-2005). | the accidental introduction of west nile virus into new york city from the old world in 1999 resulted in an epidemic in humans, horses, and birds that swept to the west coast in just 3 years. the virus is transmitted by infective mosquitoes among susceptible native birds, which serve as amplifying hosts. clinical disease occurs in humans and horses, but not enough virus is produced in their blood to infect other mosquitoes; therefore, humans and horses are considered dead-end hosts. humans can b ... | 2006 | 16611928 |
| prevalence of west nile virus antibodies in a breeding population of american kestrels (falco sparverius) in pennsylvania. | west nile virus (wnv) has been identified in nearly 300 species of wild birds, including raptors, in north america since its introduction in new york city in 1999. american kestrels (falco sparverius) are susceptible to wnv infection, and the numbers of these birds have declined along the atlantic coast in recent years. we examined the population biology and wnv exposure of kestrels breeding in the area surrounding hawk mountain sanctuary in kempton, pennsylvania, usa. the reproductive biology o ... | 2007 | 17699096 |
| characterization of a small plaque variant of west nile virus isolated in new york in 2000. | a small-plaque variant (sp) of west nile virus (wnv) was isolated in vero cell culture from kidney tissue of an american crow collected in new york in 2000. the in vitro growth of the sp and parental (wt) strains was characterized in mammalian (vero), avian (df-1 and pde), and mosquito (c6/36) cells. the sp variant replicated less efficiently than did the wt in vero cells. in avian cells, sp growth was severely restricted at high temperatures, suggesting that the variant is temperature sensitive ... | 2007 | 17617432 |
| first record of aedes japonicus japonicus in illinois: defining its spatial distribution and associated mosquito species. | since the initial discovery of aedes japonicus japonicus in 1998 from sites in the northeastern united states (new york, connecticut, and new jersey), this invasive mosquito species now permeates local faunas throughout eastern north america and continues to expand its distribution westward. in july and august of 2006, the 1st reported specimens of ae. japonicus were detected in east central illinois at 2 woodlots in southern urbana. sampling efforts were concentrated around the site of the orig ... | 2007 | 17939502 |
| a survey for west nile virus in bats from illinois. | a blocking enzyme-linked immunosorbent assay was used to test 97 serum samples from big brown bats (eptesicus fuscus) captured in six counties in illinois between may 2002 and february 2004 for west nile virus (wnv) antibodies. one female big brown bat tested positive for wnv antibodies. samples of kidney, liver, and heart tissue were collected from 312 bats of seven species that were submitted to the illinois (usa) department of public health or the illinois department of agriculture diagnostic ... | 2006 | 16870875 |
| epidemiology and transmission dynamics of west nile virus disease. | from 1937 until 1999, west nile virus (wnv) garnered scant medical attention as the cause of febrile illness and sporadic encephalitis in parts of africa, asia, and europe. after the surprising detection of wnv in new york city in 1999, the virus has spread dramatically westward across the united states, southward into central america and the caribbean, and northward into canada, resulting in the largest epidemics of neuroinvasive wnv disease ever reported. from 1999 to 2004, >7,000 neuroinvasiv ... | 2005 | 16102302 |
| west nile virus infections in organ transplant recipients--new york and pennsylvania, august-september, 2005. | in september 2005, west nile virus (wnv) infection was confirmed in three of four recipients of organs transplanted from a common donor. two recipients subsequently had neuroinvasive disease, one recipient had asymptomatic wnv infection, and a fourth recipient apparently was not infected. this report summarizes the ongoing investigation. clinicians should be aware of the potential for transplant-associated transmission of infectious disease. | 2005 | 16224451 |
| health assessment of black-crowned night-herons (nycticorax nycticorax) of the new york harbor estuary. | blood samples from 145 black-crowned night-heron (nycticorax nycticorax, bcnh) chicks (mean age 3 weeks) were taken from four island colonies (goose (2004), canarsie pol (2005), hoffman (2004 and 2005) and north brother (2004 and 2005)) in new york harbor in 2004 and 2005 to establish baseline health reference ranges for this species and to compare health indices of birds reared on different islands. packed cell volume (pcv) and total solids (ts) did not differ among islands in either year. hero ... | 2007 | 17720576 |
| dead crow density and west nile virus monitoring, new york. | new york state used the health commerce system to monitor the number of west nile virus (wnv) human disease cases and the density of dead crows. in each year from 2001 to 2003 and for the 3 years combined, persons living in new york counties (excluding new york city) with elevated weekly dead crow densities (above a threshold value of 0.1 dead crows per square mile) had higher risk (2.0-8.6 times) for disease caused by wnv within the next 2 weeks than residents of counties reporting fewer dead c ... | 2005 | 16229764 |
| geographic prediction of human onset of west nile virus using dead crow clusters: an evaluation of year 2002 data in new york state. | the risk of becoming a west nile virus case in new york state, excluding new york city, was evaluated for persons whose town of residence was proximal to spatial clusters of dead american crows (corvus brachyrhynchos). weekly clusters were delineated for june-october 2002 by using both the binomial spatial scan statistic and kernel density smoothing. the relative risk of a human case was estimated for different spatial-temporal exposure definitions after adjusting for population density and age ... | 2006 | 16306307 |
| field evaluation of cdc gravid trap attractants to primary west nile virus vectors, culex mosquitoes in new york state. | a field study was conducted to evaluate two cdc gravid trap attractants available for the west nile virus surveillance program in new york state (nys). according to potential attractiveness, a common lawn sod in nys, kentucky bluegrass (poa pratensis) infusion and a rabbit chow infusion were compared for attractiveness to primary west nile virus vectors, culex mosquitoes. attractiveness of each infusion was measured by the number of adult mosquitoes caught in cdc gravid traps and the number of e ... | 2004 | 15532922 |
| west nile virus infection among pregnant women in a northern colorado community, 2003 to 2004. | since west nile virus (wnv) was first detected in new york in 1999, it has spread across north america and become a major public health concern. in 2002, the first documented case of intrauterine wnv infection was reported, involving an infant with severe brain abnormalities. to determine the frequencies of wnv infections during pregnancy and of intrauterine wnv infections, we measured wnv-specific antibodies in cord blood from infant deliveries after a community-wide epidemic of wnv disease. | 2006 | 16510662 |
| host-feeding patterns of culex mosquitoes in relation to trap habitat. | mosquito feeding patterns identify vertebrate species potentially involved in the amplification of west nile virus. in new york, northern cardinals (cardinalis cardinalis) were the predominant hosts in most habitats. crow (corvus sp.) blood meals were most frequently identified from sewage treatment plant and storm water catch basin habitats. | 2007 | 18258048 |
| a dietary risk assessment of the pyrethroid insecticide resmethrin associated with its use for west nile virus mosquito vector control in california. | an outbreak of human illnesses associated with west nile virus (wnv) occurred in new york city in 1999. since then, it has gradually spread westwards, reaching northern california for the first time in 2005. wnv is transmitted by several mosquito species and birds serve as the main reservoir. several control measures have been used, targeting both the aquatic larvae and the adult mosquitoes. in the latter case, roosting birds in trees are sprayed with pyrethroid insecticides because these are hi ... | 2006 | 16518516 |
| crow deaths caused by west nile virus during winter. | in new york, an epizootic of american crow (corvus brachyrhynchos) deaths from west nile virus (wnv) infection occurred during winter 2004-2005, a cold season when mosquitoes are not active. detection of wnv in feces collected at the roost suggests lateral transmission through contact or fecal contamination. | 2007 | 18258045 |
| 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 ... | 2009 | 19281434 |
| west nile virus surveillance in mosquitoes in new york state, 2000-2004. | a west nile virus (wnv) surveillance system was created and implemented in new york state (nys) in 2000 and described previously (white et al. 2001). we examine and evaluate the results of mosquito and virus surveillance for 2000 through 2004 exclusive of new york city. forty-nine counties submitted 1,095,426 mosquitoes in 35,280 pools for wnv assay. specimens of 47 species were tested, with culex species accounting for 47.6% of all pools tested. wnv was detected in 814 pools from 10 species, wi ... | 2006 | 17019772 |
| 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). | 2004 | 15549023 |
| estimates of worst case baseline west nile virus disease effects in a suburban new york county. | serosurveys conducted where west nile virus (wnv) caused health impacts were used to construct a model of potential worst case health impacts in a suburban setting. this model addressed two common public perceptions regarding mosquito control activities and wnv disease: it is not a disease of major consequence, and exposed populations quickly become immune. comparisons to blood bank infection and serious disease incidence data were similar to some of the serosurvey model results. accounting for ... | 2008 | 19263849 |
| meteorologically conditioned time-series predictions of west nile virus vector mosquitoes. | 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 p ... | 2008 | 18279008 |
| density-equalizing euclidean minimum spanning trees for the detection of all disease cluster shapes. | existing disease cluster detection methods cannot detect clusters of all shapes and sizes or identify highly irregular sets that overestimate the true extent of the cluster. we introduce a graph-theoretical method for detecting arbitrarily shaped clusters based on the euclidean minimum spanning tree of cartogram-transformed case locations, which overcomes these shortcomings. the method is illustrated by using several clusters, including historical data sets from west nile virus and inhalational ... | 2007 | 17519338 |
| west nile virus activity--united states, 2006. | west nile virus (wnv) is the leading cause of arboviral encephalitis in the united states. originally discovered in africa in 1937, wnv was first detected in the western hemisphere in 1999 in new york city. since then, wnv has caused seasonal epidemics of febrile illness and severe neurologic disease in the united states. this report summarizes provisional wnv surveillance data for 2006 reported to cdc as of april 3, 2007. during 2006, wnv transmission to humans or animals expanded into 52 count ... | 2007 | 17557072 |
| pathogenicity of west nile virus and response to vaccination in sandhill cranes (grus canadensis) using a killed vaccine. | west nile virus was introduced into the united states in the vicinity of new york, new york, usa in 1999. the virus has since killed large numbers of birds nationwide, especially, but not limited to, crows (corvus brachyrhinchos). one sandhill crane (grus canadensis) at the bridgeport zoo (bridgeport, connecticut, usa) reportedly died from west nile virus, so sandhill cranes and endangered whooping cranes (grus americana), both in the wild and in captive breeding colonies at united states geolog ... | 2009 | 19569472 |
| changes in aedes albopictus (diptera: culicidae) populations in new jersey and implications for arbovirus transmission. | the asian tiger mosquito aedes albopictus (skuse) was first detected in new jersey in 1995 during mosquito surveillance operations in monmouth county. we tracked statewide changes in populations of the asian tiger mosquito and its association with west nile virus from 2003 to 2007. ae. albopictus population abundance has increased in new jersey since 2003, primarily along the urban corridor between new york city and philadelphia, and they are now expanding their range further into suburban and r ... | 2009 | 19769057 |
| declining mortality in american crow (corvus brachyrhynchos) following natural west nile virus infection. | the american crow (corvus brachyrhynchos) is known to suffer 100% mortality from infection with the new york 1999 strain of west nile virus (wnv). following the initial detection of wnv in north america in 1999, we measured prevalence of wnv-reactive antibodies ("seroprevalence") in free-ranging american and fish crows (corvus ossifragus) of central new jersey after each transmission season through 2005. in 2002, seroprevalence in american crow juveniles increased to 14% from the 5% of the previ ... | 2009 | 19848089 |
| dry weather induces outbreaks of human west nile virus infections. | since its first occurrence in the new york city area during 1999, west nile virus (wnv) has spread rapidly across north america and has become a major public health concern in north america. by 2002, wnv was reported in 40 states and the district of columbia with 4,156 human and 14,539 equine cases of infection. mississippi had the highest human incidence rate of wnv during the 2002 epidemic in the united states. epidemics of wnv can impose enormous impacts on local economies. therefore, it is a ... | 2010 | 20181272 |
| distribution and abundance of host-seeking culex species at three proximate locations with different levels of west nile virus activity. | culex species were monitored at three proximate sites with historically different west nile virus (wnv) activities. the site with human wnv transmission (epidemic) had the lowest abundance of the putative bridge vectors, culex pipiens and cx. salinarius. the site with horse cases but not human cases (epizootic) had the highest percent composition of cx. salinarius, whereas the site with wnv-positive birds only (enzootic) had the highest cx. pipiens abundance and percent composition. a total of 2 ... | 2009 | 19346396 |
| utilization of an incident command system for a public health threat: west nile virus in nassau county, new york, 2008. | the summer of 2008 in nassau county, new york, was marked by a historic season of human west nile virus illness and west nile virus activity in mosquitoes. the commissioner of health of the state of new york declared a public health threat, and a decision was made to use adulticide for mosquito control. in contrast to prior years, the nassau county department of health utilized the incident command system (ics) to coordinate a multidisciplinary and multidepartment response to this public health ... | 2010 | 20520369 |
| identification of environmental covariates of west nile virus vector mosquito population abundance. | the rapid spread of west nile virus (wnv) in north america is a major public health concern. culex pipiens-restuans is the principle mosquito vector of wnv in the northeastern united states while aedes vexans is an important bridge vector of the virus in this region. vector mosquito abundance is directly dependent on physical environmental factors that provide mosquito habitats. the objective of this research is to determine landscape elements that explain the population abundance and distributi ... | 2010 | 20482343 |
| detection of broadly distributed sodium channel alleles characteristic of insect pyrethroid resistance in west nile virus vector culex pipiens complex mosquitoes in the united states. | west nile virus (wnv) has emerged as a health threat to the north american population since its initial outbreak in new york city in 1999. culex (culex) pipiens complex mosquitoes have been considered to play the primary role in the enzootic maintenance and transmission of wnv in north america. the voltage-gated sodium channel (nach) gene contains pyrethroid resistance-associated mutations in the coding region in many insect species. however, the knowledge of potential nach mutations was minimal ... | 2009 | 19351083 |
| the effect of west nile virus perceptions and knowledge on protective behavior and mosquito breeding in residential yards in upstate new york. | a knowledge, attitudes, and practices (kap) questionnaire combined with entomological surveys of residential mosquito-breeding sites were conducted in two upstate new york neighborhoods. we tested the hypothesis that "correct" west nile virus (wnv) knowledge and perceptions correspond with the use of practices that prevent mosquitoes from breeding and biting. our results demonstrate that perceptions of wnv relate to the number of positive containers in yards and the use of mosquito preventive me ... | 2009 | 19452223 |
| west nile virus activity--united states, 2007. | west nile virus (wnv) is the leading cause of arboviral encephalitis in the united states. originally identified in africa in 1937, wnv was first detected in the western hemisphere in 1999 in new york city. since then, wnv has caused seasonal epidemics of febrile illness and neurologic disease in the united states. this report summarizes national wnv surveillance data for 2007. wnv transmission to humans or animals expanded into 19 counties that had not reported transmission previously and recur ... | 2008 | 18600197 |
| two new real-time quantitative reverse transcription polymerase chain reaction assays with unique target sites for the specific and sensitive detection of lineages 1 and 2 west nile virus strains. | two novel 1-step real-time quantitative reverse transcription polymerase chain reaction (qrt-pcr) assays for the simultaneous detection of west nile virus (wnv) lineage 1 and 2 strains were developed. primers and the probe of assay 1 target the 5'-untranslated region (utr), whereas the amplicon of assay 2 is located in the nonstructural region ns2a, which enables an unambiguous and independent wnv diagnosis based on 2 different amplicons. both assays allow the detection of as few as 2-4 genome c ... | 2010 | 20807934 |
| assessment of a novel real-time pan-flavivirus rt-polymerase chain reaction. | outbreaks of west nile virus (wnv) have occurred intermittently in regions around the mediterranean coast, and the virus may have become established in northern italy and romania, with reported intermittent outbreaks in spain, hungary, and france. wnv has also spread rapidly throughout the americas since its introduction into new york in 1999. this capacity to emerge in new geographical locations and to spread rapidly together with the current increase in incidence of other flaviviruses such as ... | 2010 | 20854019 |
| factors associated with the risk of west nile virus among crows in new york state. | west nile virus (wnv) is transmitted between avian hosts in enzootic cycles by a mosquito vector. the virus has significant disease effects on humans and equines when it bridges into an epizootic cycle. as the initial epidemic of wnv in 1999, perennial outbreaks in new york state suggest the local establishment of natural foci with perpetuation of the virus among susceptible hosts rather than reintroduction of the virus. the factors that play a role in the perpetuation of the virus are not fully ... | 2011 | 20707862 |
| west nile virus activity - united states, 2009. | west nile virus (wnv) was first detected in the western hemisphere in 1999 in new york city and has since caused seasonal epidemics of febrile illness and neurologic disease across the united states, where it is now the leading cause of arboviral encephalitis. this report updates a previous report and summarizes wnv activity in the united states reported to cdc in 2009. a total of 38 states and the district of columbia (dc) reported 720 cases of wnv disease. of these, 33 states and dc reported 3 ... | 2010 | 20592686 |