West Nile Virus (WNV) is a mosquito-borne virus that affects horses, causing neurological disease. It is transmitted primarily through the bite of infected mosquitoes, which acquire the virus from feeding on infected birds. Horses are considered a dead-end host, meaning they do not contribute to the transmission cycle of the virus. Clinical signs in horses can range from mild fever and lethargy to severe neurological symptoms such as ataxia, weakness, and paralysis. Diagnosis is typically confirmed through serological testing or detection of the virus in tissues. Vaccination is available and serves as a preventive measure to reduce the incidence of the disease. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, clinical presentation, and management of West Nile Virus in equine populations.
Romi R, Pontuale G, CIufolini MG, Fiorentini G, Marchi A, Nicoletti L, Cocchi M, Tamburro A.In the late summer of 1998, an outbreak of equine encephalomyelitis due to West Nile virus (WNV) occurred in the Tuscany region of central Italy. The disease was detected in 14 race horses from nine localities in four Provinces: Firenze, Lucca, Pisa and Pistoia. The outbreak area included Fucecchio wetlands (1800 ha), the largest inland marsh in Italy, and the adjacent hilly Cerbaie woodlands with farms breeding horses. To detect potential vectors of WNV, entomological surveys of Fucecchio and Cerbaie were undertaken during 1999-2002 by collecting mosquito larvae from breeding sites and adult ...
Nelson DM, Gardner IA, Chiles RF, Balasuriya UB, Eldridge BF, Scott TW, Reisen WK, Maclachlan NJ.Jamestown Canyon (JC) and Saint Louis encephalitis (SLE) viruses are mosquito-transmitted viruses that have long been present in California. The objective of this study was to determine the seroprevalence of these two viruses in horses prior to the introduction of West Nile (WN) virus. Approximately 15% of serum samples collected in 1998 from 425 horses on 44 equine operations horses throughout California had serum antibodies to JC virus, whereas antibodies were not detected to SLE virus. The results indicate that horses in California were commonly infected prior to 1998 with mosquito-transmit...
Kleiboeker SB, Loiacono CM, Rottinghaus A, Pue HL, Johnson GC.The North American West Nile virus (WNV) epizootic, which began in 1999, has caused significant morbidity and mortality in horses. Because experimental infection has failed to consistently produce encephalitis in inoculated horses, investigation of naturally occurring cases was used to optimize strategies for diagnosis of this disease. Although WNV RNA could be detected by reverse transcriptase-polymerase chain reaction (RT-PCR) performed on whole blood collected from both clinically affected horses and unaffected herdmates, the diagnostic sensitivity of this approach was low compared with IgM...
Zeller HG, Schuffenecker I.West Nile (WN) virus is a mosquito-transmitted flavivirus. It is widely distributed in Africa, the Middle East, Asia, and southern Europe and was recently introduced to North America. Birds are involved in the cycle of transmission as amplifying hosts. Humans and horses are considered accidental dead-end hosts. WN fever was initially considered a minor arbovirosis, usually inducing a nonsymptomatic or a mild flu-like illness in humans, but some cases of encephalitis associated with fatalities were reported in Israel in the 1950s. After two silent decades, several human and equine outbreaks of ...
Ng T, Hathaway D, Jennings N, Champ D, Chiang YW, Chu HJ.To meet the urgent need of controlling West Nile virus (WNV) infection in the equine population, we have developed a killed WNV vaccine. A dose titration study in horses was first conducted to evaluate serum neutralization antibody responses against WNV in these animals. Horses were vaccinated intramuscularly twice with the test vaccine at low, medium and high dose, three weeks apart. Serum samples were collected periodically and were measured for serum neutralizing antibody using a plaque reduction neutralization test. Significant increases in serum neutralizing antibody were detected in all ...
Weissenböck H, Hubálek Z, Halouzka J, Pichlmair A, Maderner A, Fragner K, Kolodziejek J, Loupal G, Kölbl S, Nowotny N.Avian mortality and encephalomyelitis in equines are considered good indicators for West Nile virus (WNV) activity. We retrospectively tested 385 horse sera for WNV antibodies and looked for WNV nucleic acid and/or WNV antigen in paraffin embedded tissues from 12 horses with aetiologically unresolved encephalomyelitis and 102 free-living birds of different species which had been found dead. With the exception of four horses originating from eastern European countries investigated on the occasion of transit through Austria, all horse sera were negative. Nested RT-PCR of the horse tissues yielde...
Guthrie AJ, Howell PG, Gardner IA, Swanepoel RE, Nurton JP, Harper CK, Pardini A, Groenewald D, Visage CW, Hedges JF, Balasuriya UB, Cornel AJ....West Nile virus (WNV) infection is endemic in southern Africa. With the recent emergence of WNV infection of horses in Europe and the USA the present study was performed to estimate the risk of seroconversion to WNV in a cohort of 488 young Thoroughbred (TB) horses. Objective: To estimate the risk of seroconversion to WNV among a cohort of South African TB yearlings sold at the 2001 National Yearling Sales (NYS) and to determine whether the risk varied geographically. Two horses were also infected with a recent South African isolate of WNV to evaluate its virulence in horses. Methods: Serum sa...
Blackmore CG, Stark LM, Jeter WC, Oliveri RL, Brooks RG, Conti LA, Wiersma ST.After West Nile virus (WNV) was first detected in Florida in July 2001, intensive surveillance efforts over the following five months uncovered virus activity in 65 of the state's 67 counties with 1,106 wild birds, 492 horses, 194 sentinel chickens, and 12 people found infected with the virus. Thirteen of 28 mosquito isolations came from Culex mosquitoes. As seen in the northeastern United States, wild bird mortality was the most sensitive surveillance method. However, unlike the predominantly urban 1999 and 2000 epizootics, the Florida transmission foci were rural with most activity detected ...
This report summarizes West Nile virus (WNV) surveillance data reported to CDC through ArboNET as of 3 a.m., Mountain Daylight Time, September 10, 2003.
Loroño-Pino MA, Blitvich BJ, Farfán-Ale JA, Puerto FI, Blanco JM, Marlenee NL, Rosado-Paredes EP, García-Rejón JE, Gubler DJ, Calisher CH....Serum samples were obtained from 252 horses in the State of Yucatan, Mexico, from July to October 2002. Antibodies to West Nile virus were detected by epitope-blocking enzyme-linked immunosorbent assays in three (1.2%) horses and confirmed by plaque reduction neutralization test. We report the first West Nile virus activity in the State of Yucatan.
Blitvich BJ, Fernandez-Salas I, Contreras-Cordero JF, Marlenee NL, Gonzalez-Rojas JI, Komar N, Gubler DJ, Calisher CH, Beaty BJ.Serum samples were obtained from 24 horses in the State of Coahuila, Mexico, in December 2002. Antibodies to West Nile virus were detected by epitope-blocking enzyme-linked immunosorbent assay and confirmed by plaque reduction neutralization test in 15 (62.5%) horses. We report the first West Nile virus activity in northern Mexico.
Weese JS, Baird JD, DeLay J, Kenney DG, Staempfli HR, Viel L, Parent J, Smith-Maxie L, Poma R.West Nile virus encephalomyelitis was diagnosed in 28 horses presented to the Ontario Veterinary College Veterinary Teaching Hospital between August 20 and October 15, 2002. The age range of affected horses was 5 months to 20 years (mean 6.9 years, median 6 years). Clinical signs were highly variable. Duration of hospitalization ranged from < 1 to 12 days (mean 5 days, median 5.4 days). Overall, 16 of the 28 (57%) horses were discharged and, of the 14 from which follow-up information was available, 13 (93%) were reported to be clinically normal 4 to 6 weeks following discharge, while the other...
Barker CM, Reisen WK, Kramer VL.The California Mosquito-Borne Virus Surveillance and Response Plan recently was developed to provide a semi-quantitative means for assessing risk for western equine encephalomyelitis (WEE) or St. Louis encephalitis (SLE) viruses and to provide intervention guidelines for mosquito control and public health agencies during periods of heightened risk for human infection. West Nile virus recently has arrived in California, and the response plan also will provide a baseline for assessing the risk for human and equine infection with this virus. In the response plan, overall risk is calculated by ave...
Ulloa A, Langevin SA, Mendez-Sanchez JD, Arredondo-Jimenez JI, Raetz JL, Powers AM, Villarreal-Treviño C, Gubler DJ, Komar N.A serologic survey in domestic animals (birds and mammals) was conducted in four communities located in the Lacandón Forest region of northeastern Chiapas, Mexico, during June 29 to July 1, 2001, with the objective to identify zoonotic arboviruses circulating in this area. We collected 202 serum samples from healthy domestic chickens, geese, ducks, turkeys, horses and cattle. The samples were tested by plaque-reduction neutralization test for antibodies to selected mosquito-borne flaviviruses (family Flaviviridae), including St. Louis encephalitis (SLE), Rocio (ROC), Ilheus (ILH), Bussuquara ...
Banet-Noach C, Malkinson M, Brill A, Samina I, Yadin H, Weisman Y, Pokamunski S, King R, Deubel V, Stram Y.In November 1997, an outbreak of a neuroparalytic disease caused by West Nile (WN) virus was diagnosed in young goose flocks. Domestic geese were similarly affected in the late summer and fall of 1998, 1999, 2000 and 2001. WN viruses were also isolated from migratory and wild birds and horses in 1998-2001. A 1278 bp sequence of the envelope gene of 24 Israeli WN virus isolates was compared with those of seven isolates from Africa, Europe and New York. As a result, the Israeli isolates could then be grouped into two clusters. The 15 avian and three equine from 1997-2001 in the first cluster of ...
Blitvich BJ, Bowen RA, Marlenee NL, Hall RA, Bunning ML, Beaty BJ.We evaluated the ability of epitope-blocking enzyme-linked immunosorbent assays (ELISAs) to detect West Nile virus (WNV) antibodies in domestic mammals. Sera were collected from experimentally infected horses, cats, and pigs at regular intervals and screened in ELISAs and plaque reduction neutralization tests. The diagnostic efficacies of these techniques were similar.
Porter MB, Long MT, Getman LM, Giguère S, MacKay RJ, Lester GD, Alleman AR, Wamsley HL, Franklin RP, Jacks S, Buergelt CD, Detrisac CJ.To determine signalment, clinical findings, results of diagnostic testing, outcome, and postmortem findings in horses with West Nile virus (WNV) encephalomyelitis. Methods: Retrospective study. Methods: 46 horses with WNV encephalomyelitis. Methods: Clinical data were extracted from medical records of affected horses. Results: On the basis of clinical signs and results of serologic testing, WNV encephalomyelitis was diagnosed in 46 of 56 horses with CNS signs. Significantly more males than females were affected. Increased rectal temperature, weakness or ataxia, and muscle fasciculations were t...
Kent RJ, Lacer LD, Meisch MV.Migratory birds could introduce West Nile (WN) virus to Arkansas. The purpose of this study was to establish a cooperative arbovirus surveillance program to monitor mosquitoes and birds in Arkansas for arboviruses. Our objectives were to: 1) perform routine, multicounty collections of mosquitoes and test them for eastern equine encephalitis, St. Louis encephalitis, and WN viruses; and 2) conduct passive surveillance by testing dead wild birds for WN virus. Arbovirus surveillance was organized by the Arkansas Department of Health, University of Arkansas, and Vector Disease Control Incorporated....
Wang T, Magnarelli LA, Anderson JF, Gould LH, Bushmich SL, Wong SJ, Fikrig E.Recombinant West Nile virus envelope (E) protein was examined in enzyme-linked immunosorbent assay (ELISA) to detect antibodies elicited during West Nile virus infection. Horses (nine of 10) and humans (six of six) with confirmed West Nile virus infection had IgG and/or IgM antibodies to the E protein. Antibodies to the recombinant West Nile virus membrane and nonstructural 1 proteins were not detected in any of these sera. An E protein-based ELISA may aid in the serological diagnosis of West Nile virus infection.
Autorino GL, Battisti A, Deubel V, Ferrari G, Forletta R, Giovannini A, Lelli R, Murri S, Scicluna MT.During the late summer of 1998, veterinary authorities in Tuscany, Italy, received reports of cases of neurologic disease among horses residing in a large wetland area located in the provinces of Florence and Pistoia. West Nile virus was isolated from two of the six horses that died or were euthanized. A retrospective epidemiologic study identified 14 clinical neurologic cases that occurred from August 20 to October 6 (attack rate of 2.8%). A serologic survey conducted over a 700-km2 area in stables with and without apparent clinical cases confirmed a wider spread of the infection, with an ove...
Wamsley HL, Alleman AR, Porter MB, Long MT.To evaluate CSF in horses with confirmed West Nile virus encephalomyelitis. Methods: Retrospective study. Methods: 30 horses. Methods: Results of CSF analyses from horses with acute neurologic signs attributed to West Nile virus infection that was confirmed by immunoglobulin M antibody capture ELISA were reviewed and analyzed. Results: Among 30 CSF samples, findings in 8 (27%) were within reference ranges and in 22 (73%) were abnormal. Among the 22 abnormal samples, mononuclear pleocytosis was found in 16 (73%) and high protein concentration with nucleated cell count within reference range was...
This report summarizes West Nile virus (WNV) surveillance data reported to CDC through ArboNET and verified by states and other jurisdictions as of July 23, 2002. During the reporting week of July 17-23, nine human cases of WNV were reported from two states (Louisiana and Mississippi). During the same period, WNV infections were reported in 202 dead crows, 48 other dead birds, 13 horses, and 69 mosquito pools.
Beckwith WH, Sirpenski S, French RA, Nelson R, Mayo D.The emergence of the West Nile virus (WNV) in the northeastern United States has drawn emphasis to the need for expanded arbovirus surveillance in Connecticut. Although the state of Connecticut began a comprehensive mosquito-screening program in 1997, only since 1999 have there been efforts to determine the prevalence of arboviruses in bird populations in this state. Herein, we report on our results of an arbovirus survey of 1,704 bird brains. Included in this report are the first known isolations of eastern equine encephalitis virus (EEEV) from crows and data on the geographic and temporal di...
Steinman A, Banet C, Sutton GA, Yadin H, Hadar S, Brill A.Between August and October 2000, 76 horses were reported by veterinary practitioners as having signs of a neurological disorder, varying from an involvement of the spinal cord alone to the entire central nervous system; 15 of the horses died or were euthanased as a result of their grave prognosis or secondary complications. At the same time, an outbreak of West Nile virus infection affected people and birds, principally domestic geese. West Nile virus was isolated from four of the horses with encephalomyelitis and five other horses seroconverted, indicating that the virus was the probable caus...
Piero FD.This letter refers to the Veterinary Pathology brief communication “West Nile Virus Infection in Horses: Detection by Immunohistochemistry, In Situ Hybridization, and ELISA” by Toplu et al.5 The authors attempt to describe the clinicopathologic findings in naturally occurring West Nile virus (WNV) infection in horses. WNV was diagnosed in a foal by immunohistochemical and in situ hybridization techniques, and the presence of WNV antibodies was detected in 5 other horses with clinical signs suggestive of WNV infection. The foal was the only animal that received a complete postmortem and his...
Mentoor JL, Lubisi AB, Gerdes T, Human S, Williams JH, Venter M.We report here the complete genome sequence of a lineage 2 West Nile virus (WNV) strain that resulted in fatal neurological disease in a horse in South Africa. Several recent reports exist of neurological disease associated with lineage 2 WNV in humans and horses in South Africa and Europe; however, there are a lack of sequencing data from recent fatal cases in Southern Africa, where these strains likely originate. A better understanding of the genetic composition of highly neuroinvasive lineage 2 strains may facilitate the identification of putative genetic factors associated with increased v...
Laabassi F, Dheilly N, Beck C, Amaral R, Gonzalez G, Gaudaire D, Madeline A, Lecouturier F, Lecollinet S, Zientara S, Hans A, Valle-Casuso JC.In order to determine the prevalence of equine infectious anemia virus (EIAV), Usutu virus (USUV), and West Nile virus (WNV) in eastern Algerian drylands, 340 sera from distinct equids have been collected from 2015 to 2017. Serological analysis for the presence of antibodies against EIAV and flaviviruses was performed using commercially available ELISAs. Sera detected positive, doubtful, or negative close to the doubtful threshold in flavivirus ELISA were tested by the virus neutralization test (VNT), using WNV and USUV strains. The prevalence of WNV antibodies with ELISA was 11.47% (39/340) a...
Roberts H, Lopez M, Hartley M.African swine fever in the Caucasus and Leningrad regions of Russia. Equine infectious anaemia in several EU member states. Foot-and-mouth disease in Bulgaria--the first in an EU member state since 2007. Highly pathogenic avian influenza H5N1 in the Far East. West Nile virus in southern Europe. These are among matters discussed in the international disease monitoring report for October to December 2010, prepared by Defra's Food and Farming Group, Veterinary Science Team.
Epp T, Waldner C, Leighton FA, Berke O, Townsend HG.The primary objectives of this study were to determine the seroprevalence of West Nile virus (WNV) infection of horses in Saskatchewan in 2003 and to identify risk factors for the infection. Blood samples were collected in August and October from 212 horses in 20 herds in 5 geographic zones. After accounting for within-herd clustering, the proportion of horses that had been infected with WNV, as determined by IgG and IgM antibody response, was 55.7% (95% confidence interval, 44.9% to 65.8%). The proportion of antibody-positive horses differed among herds (0% to 100%) and across ecoregions (20%...
Kotelevska TM, Pryimenko NO, Dubynska HM, Iziumska OM, Koval TI, Pikul KV, Purdenko TY.West Nile Fever (WNF) is the most common arbovirus infection caused by West Nile Virus (WNV), which has been responsible for numerous epidemic outbreaks of disease among humans, birds and horses on all continents, with the exception of Antarctica, over the past two decades. On the territory of Ukraine, the earliest reports of cases of WNV circulation in humans and birds relate to the 70s of the XX century. In Poltava region WNF was first registered in 2011. Though the epidemiological and clinical patterns of WNF in Ukraine and Poltava region remain understudied, primarily due to the lack of al...
Tanner JM, Traub-Dargatz JL, Hill AE, Van Campen H, Knight AP, Cunningham WE, Salman MD.To describe the prevalence of West Nile virus (WNV) infection and evaluate factors associated with positive IgM capture ELISA results in equids with clinical signs compatible with WNV infection. Methods: Retrospective case series. Methods: Laboratory submission forms from 1,104 equids tested for WNV in Colorado in 2003. Methods: Submission forms accompanying samples submitted for detection of WNV via IgM capture ELISA were obtained from the Colorado state veterinarian and diagnostic laboratories performing the tests. Data on signalment, clinical signs, history of vaccination against WNV, and a...
Rebollo B, Sarraseca J, Lecollinet S, Abouchoaib N, Alonso J, García-Bocanegra I, Sanz AJ, Venteo Á, Jiménez-Clavero MA.West Nile virus (WNV) is a zoonotic arboviral pathogen affecting humans, birds, and horses. Vaccines are available for veterinary use, which efficiently prevent the infection in horses. Most common diagnostic tools rely on the identification of the agent (RT-PCR, virus isolation), or on the detection of antibodies (IgM and IgG) recognizing structural proteins of the virus or neutralizing virus infection in cell cultures (virus-neutralization tests). The recent emergence of WNV in different parts of the world has resulted in an increase in the vaccination of horses in many countries. Methods fo...
Recent outbreaks of equine infectious anaemia and equine viral arteritis in the UK. Update on the equine infectious anaemia situation in Europe. West Nile virus reported in several Mediterranean countries. Current and future approaches to equine viral arteritis control in the UK. These are among matters discussed in the quarterly equine disease surveillance report for April to June 2010, prepared by Defra, the Animal Health Trust and the British Equine Veterinary Association.
first infected cases caused by West Nile virus were reported in Cuba in 2004. Objective: to monitor and learn about the prevalence of the West Nile virus in those areas with confirmed cases. Methods: the study was conducted in Jatibonico municipality and in the city of sancti Spiritus. A total number of 14 persons, 8 horses and 41 birds were researched to detect antibodies to flavivirus and specific antibodies to West Nile virus. Results: the presence of specific antibodies to West Nile virus was confirmed in 4 samples of sera from birds and in 4 from horses. One person was confirmed as one ca...
Behrens NE, Gershwin LJ.Hypersensitivity reactions, such as hives or fatal anaphylactic shock, in response to vaccination constitute a health hazard for horses that develop allergies to vaccine components. In such horses vaccination with viral vaccines stimulates an IgE response to non-target antigens. Viral vaccines share contaminating non-target proteins, such as bovine serum albumin (BSA); these antigens can stimulate IgE production with each exposure. We hypothesized that the addition of a CpG oligodeoxynucleotide (ODN) administered in conjunction with a West Nile virus vaccine would decrease the IgE response; th...
Anderson C, Baha H, Boghdeh N, Barrera M, Alem F, Narayanan A.Zoonotic pathogens that are vector-transmitted have and continue to contribute to several emerging infections globally. In recent years, spillover events of such zoonotic pathogens have increased in frequency as a result of direct contact with livestock, wildlife, and urbanization, forcing animals from their natural habitats. Equines serve as reservoir hosts for vector-transmitted zoonotic viruses that are also capable of infecting humans and causing disease. From a One Health perspective, equine viruses, therefore, pose major concerns for periodic outbreaks globally. Several equine viruses ha...
Chalhoub FLL, Horta MAP, Alcantara LCJ, Morales A, Dos Santos LMB, Guerra-Campos V, Rodrigues CDS, Santos CC, Mares-Guia MAM, Pauvolid-Corrêa A....Infections with arboviruses are reported worldwide. Saint Louis encephalitis (SLEV) and West Nile (WNV) viruses are closely related flaviviruses affecting humans and animals. SLEV has been sporadically detected in humans, and corresponding antibodies have been frequently detected in horses throughout Brazil. WNV was first reported in western Brazil over a decade ago, has been associated with neurological disorders in humans and equines and its prevalence is increasing nationwide. Herein, we investigated by molecular and serological methods the presence of SLEV and WNV in equines from Rio de Ja...
Patroca da Silva S, Barbosa de Almeida Medeiros D, Ribeiro Cruz AC, Marques França AF, Diniz Nunes BT, Guerreiro Rodrigues DS, Pinto da Silva EV....In 2018, during the surveillance for West Nile virus (WNV) in horses with neurological clinical signs in the state of Espírito Santo (Brazil), 19 animals were investigated, and 52 biological samples were collected for WNV diagnostic. One brain sample was positive for WNV by RT-qPCR and the virus was isolated in C6/36 cell culture and sequenced. We obtained a nearly complete genome of WNV co-infected with Peruvian horse sickness virus (PHSV) in the cell culture. After confirmation of PHSV by next-generation sequencing, a new PHSV RT-qPCR protocol was developed, which was used to detect another...
Vignjević G, Vrućina I, Sestak I, Turić N, Bogojević MS, Merdić E.The West Nile Virus (WNV) is a zoonotic arbovirus that has recently been causing outbreaks in many countries in southern and Central Europe. In 2012, for the first time, it caused an outbreak in eastern Croatia with total of 7 human clinical cases. With an aim of assisting public health personnel in order to improve survey protocols and vector control, the high risk areas of the WNV transmission were estimated and mapped. The study area included cities of Osijek and Slavonski Brod and 8 municipalities in Vukovarsko-Srijemska County. Risk estimation was based on seroprevalence of WNV infections...
Cazeau G, Leblond A, Sala C, Froustey M, Beck C, Lecollinet S, Tapprest J.Few studies about the use of quantitative equine mortality data for monitoring purposes are available. Our study evaluated the utility of monitoring emerging equine diseases using mortality data collected by rendering plants. We used approaches involving modelling of historical mortality fluctuations and detection algorithm methods to analyse changes in equine mortality in connection with the West Nile Virus (WNV) outbreak that occurred between July and September 2015 along the Mediterranean coast of France. Two weeks after the first equine WNV case was detected by clinical surveillance, detec...
Trachsel DS, Drozdzewska K, Bergmann F, Ziegler U, Gehlen H.West Nile virus (WNV) is a mosquito-borne viral pathogen of global importance and is considered to be the most widespread flavivirus. In Germany, first infections with WNV were detected in 2018 and it is expected for these to become more frequent in consequence to warmer winters followed by a rainy/humid springtime. WNV is maintained in an enzootic cycle between ornithophilic mosquitoes and certain wild bird species. Humans and horses are so-called "dead-end hosts" of a WNV infection. They frequently do not fall ill, however occasionally develop overt infections ranging from mild febrile sympt...
Mazzei M, Savini G, Di Gennaro A, Macchioni F, Prati MC, Guzmàn LR, Tolari F.West Nile virus (WNV) is a mosquito-borne virus belonging to the family Flaviviridae included in the Japanese encephalitis antigenic complex (JEAC). A seroepidemiological study was carried out in 2011 using 160 horse sera collected from different areas of Bolivia to investigate the presence of WNV antibody. A high proportion (59.4%) of the tested sera were positive to a commercially available WNV competitive enzyme-linked immunosorbent assay (C-ELISA). Sixty-six randomly selected C-ELISA-positive sera were further tested by WNV plaque reduction neutralization test (PRNT), virus neutralization ...
Docherty DE, Samuel MD, Egstad KF, Griffin KM, Nolden CA, Karwal L, Ip HS.After the 2001 occurrence of West Nile virus (WNV) in Wisconsin (WI), we collected sera, during 2003-2006, from south-central WI mesopredators. We tested these sera to determine WNV antibody prevalence and geometric mean antibody titer (GMAT). Four-fold higher antibody prevalence and 2-fold higher GMAT in 2003-2004 indicated greater exposure of mesopredators to WNV during the apparent epizootic phase. The period 2005-2006 was likely the enzootic phase because WNV antibody prevalence fell to a level similar to other flaviviruses. Our results suggest that, in mesopredators, vector-borne transmis...
Dauphin G, Zientara S.West Nile virus, a flavivirus transmitted by mosquitoes, has been intensively studied since a few years because of epidemics/epizootics it has caused the last ten years, in particular around the Mediterranean basin and on the North-American continent. This virus mainly circulates in birds ; migrating bird species disseminate the virus while resident species could play a role in viral cycle amplification. A large number of mammal, amphibian and reptile species can also be infected. This virus can cause a lethal disease in humans and horses. For this reason, an active and/or passive surveillance...
Hedell R, Andersson MG, Faverjon C, Marcillaud-Pitel C, Leblond A, Mostad P.A potentially sensitive way to detect disease outbreaks is syndromic surveillance, i.e. monitoring the number of syndromes reported in the population of interest, comparing it to the baseline rate, and drawing conclusions about outbreaks using statistical methods. A decision maker may use the results to take disease control actions or to initiate enhanced epidemiological investigations. In addition to the total count of syndromes there are often additional pieces of information to consider when assessing the probability of an outbreak. This includes clustering of syndromes in space and time as...
Ząbek T, Semik E, Wnuk M, Fornal A, Gurgul A, Bugno-Poniewierska M.DNA methylation patterns and their relation with genetic polymorphisms were determined in the equine OAS1 locus. Genetic variants of OAS1 were previously found to be associated with susceptibility to West Nile virus infections in horses. The subject of the study were white blood cells of 13 juvenile and 13 old horses from AA and HC breed and a set of solid tissues from a single adult horse. The aim was to determine the degree of variation of CpG methylation profiles with concern for tissue type, horse breed and age. Results of direct BSPCR and cloned BSPCR sequencing revealed that all of deter...
Kuhn KG, Shelton K, Sanchez G, Zamor R, Bohanan K, Nichols M, Morris L, Robert J, Austin A, Dart B, Bolding B, Maytubby P, Vogel J, Stevenson B.West Nile Virus (WNV) is the most widespread and frequently reported mosquito-borne disease in the US, with a high risk of outbreaks. Accurate surveillance of WNV is complicated by many mild or asymptomatic infections, resulting in human cases being under-reported and disease distribution and transmission not being well understood. In this study, we investigated how wastewater surveillance can be used for monitoring WNV in Oklahoma. We analyzed samples collected from wastewater treatment facilities in 16 counties during July 1 to September 31, 2023, for the presence of WNV genetic material and...
Tolnai CH, Forgách P, Marosi A, Fehér O, Paszerbovics B, Tenk M, Wagenhoffer Z, Kutasi O.In the last three decades, West Nile virus (WNV, Flaviviridae, Orthoflavivirus genus) has become one of the most important encephalitic agents worldwide, causing substantial numbers of cases in humans and horses every year by re-emerging in endemic areas and emerging in new territories. It is considered that after natural WNV infection, humans and birds develop long-term immunoprotection, but data on immunoprotection in horses is scarce. Objective: West Nile virus infection provides long-term humoral immunity in subclinically infected horses. Methods: Client-owned, naturally WNV subclinically ...
Schwarzer A, Ziegler U, Fertey J, Kreuz M, Vahlenkamp TW, Groschup MH, Ulbert S.West Nile virus (WNV), Usutu virus (USUV) and tick-borne encephalitis virus (TBEV) are worldwide endemic zoonotic orthoflaviviruses, often co-circulating in the same areas. Serological studies in animals, mostly birds and horses, are important means to monitor the spread of these viruses and the infection risks for humans. However, cross-reactive antibodies to these structurally similar flaviviruses frequently impact serological differentiation in enzyme-linked immunosorbent assays (ELISAs), hence time-consuming virus neutralization tests (VNTs) have to be employed in laboratories with high bi...
