Equine Outbreaks Research Articles

Survey of state animal health officials reveals lack of personnel and resources to manage equine infectious disease outbreaks.

The purpose of the study was to assess the challenges faced by state animal health officials (SAHOs) when managing equine disease outbreaks. A survey was conducted to assess SAHOs' collaboration with horse owners and practicing veterinarians to provide biosecurity and infection disease control. It was sent to 180 email addresses listed in the Equine Disease Communication Center website database. The responses in each category for each question were tabulated and reported as a percentage. There were 72 survey responses from 45 states. The number of states responding suggested that the results represent SAHOs' current opinions. Fifty percent of responders identified the lack of resources and training for equine health management and equine reportable disease prevention and control. There is a lack of owner compliance in managing disease outbreaks, and boarding stables, horse shows, and racing facilities require the most resources for outbreak management. The survey indicated on-site communication as the most effective for managing an outbreak, and the Equine Disease Communication Center is to be a valued resource for alerts and disease information. At the state level, there is a lack of needed personnel and resources to effectively manage an equine infectious disease outbreak. Furthermore, failure of veterinary and owner compliance in reporting and managing equine infectious diseases allows disease spread. Lack of sufficient resources for management of reportable diseases will potentially result in disease spread with a negative impact on horse health and the equine industry.

Equine dermatitis outbreak associated with parapoxvirus

Equine dermatitis outbreak associated with parapoxvirus

Equine dermatitis outbreak associated with parapoxvirus.

Parapoxviruses (PPV) cause skin and mucous membrane lesions in several animal species, and of the five recognized PPVs, at least three are zoonotic. Equine PPV (EqPPV) is the sixth one initially described in humans in the United States and later in a severely sick horse in Finland in 2013-2015. In 2021-2022, a large-scale pustulo-vesicular pastern dermatitis outbreak occurred in horses all over Finland. This study aimed at analysing the outbreak, identifying and describing the causative agent, describing clinical signs, and searching for risk factors. EqPPV was identified as a probable causative agent and co-infections with several potentially pathogenic and zoonotic bacteria were observed. Histopathologically, suppurative and ulcerative dermatitis was diagnosed. Due to the lack of specific tests for this virus, we developed a novel diagnostic EqPPV-PCR with sensitivity of 10 copies/reaction. Based on a large proportion of the genome sequenced directly from clinical samples, very little variation was detected between the sequences of the case from 2013 and the cases from 2021 to 2022. Based on an epidemiological survey, the main risk factor for pastern dermatitis was having racehorses. Approximately one third of the horses at each affected stable got clinical dermatitis, manifesting as severe skin lesions. Skin lesions were also occasionally reported in humans, indicating potential zoonotic transmission. Case stables commonly reported attendance at race events before acquiring the disease. Survey also identified differences in practises between case and control stables. Taken together, these results enable a better preparedness, diagnostics, and guidelines for future outbreaks.

Reoccurrence of West Nile virus lineage 1 after 2-year decline: first equine outbreak in Campania region

West Nile virus (WNV) is the most widespread arbovirus worldwide, responsible for severe neurological symptoms in humans as well as in horses and birds. The main reservoir and amplifier of the virus are birds, and migratory birds seem to have a key role in the introduction and spread of WNV during their migratory routes. WNV lineage 1 (L1) has been missing in Italy for almost 10 years, only to reappear in 2020 in two dead raptor birds in southern Italy. The present study reports the first equine outbreak in the Campania region. A 7-year-old horse died because of worsening neurological signs and underwent necropsy and biomolecular analyses. WNV-L1 was detected by real-time RT-PCR in the heart, brain, gut, liver, and spleen. Next Generation Sequence and phylogenetic analysis revealed that the strain responsible for the outbreak showed a nucleotide identity of over 98% with the strain found in Accipiter gentilis 2 years earlier in the same area, belonging to the WNV-L1 Western-Mediterranean sub-cluster. These results underline that WNV-L1, after reintroduction in 2020, has probably silently circulated during a 2-year eclipse, with no positive sample revealed by both serological and biomolecular examinations in horses, birds, and mosquitoes. The climate changes that have occurred in the last decades are evolving the epidemiology of WNV, with introductions or re-introductions of the virus in areas that were previously considered low risk. Thereby, the virus may easily amplify and establish itself to reappear with sporadic evident cases in susceptible hosts after several months or even years.

Mapping Eastern (EEE) and Venezuelan Equine Encephalitides (VEE) among Equines Using Geographical Information Systems, Colombia, 2008–2019

Eastern equine encephalitis virus (EEEV) and Venezuelan equine encephalitis virus (VEEV) viruses are zoonotic pathogens affecting humans, particularly equines. These neuroarboviruses compromise the central nervous system and can be fatal in different hosts. Both have significantly influenced Colombia; however, few studies analyse its behaviour, and none develop maps using geographic information systems to characterise it. To describe the temporal-spatial distribution of those viruses in Colombia between 2008 and 2019. Retrospective cross-sectional descriptive study, based on weekly reports by municipalities of the ICA, of the surveillance of both arboviruses in equines, in Colombia, from 2008 to 2019. The data were converted into databases in Microsoft Access 365®, and multiple epidemiological maps were generated with the Kosmo RC1®3.0 software coupled to shape files of all municipalities in the country. In the study period, 96 cases of EEE and 70 of VEE were reported, with 58% of EEE cases occurring in 2016 and 20% of EEV cases in 2013. The most affected municipalities for EEE corresponded to the department of Casanare: Yopal (20), Aguazul (16), and Tauramena (10). In total, 40 municipalities in the country reported ≥1 case of EEE. The maps allow a quick appreciation of groups of neighbouring municipalities in different departments (1° political division) and regions of the country affected by those viruses, which helps consider the expansion of the disease associated with mobility and transport of equines between other municipalities, also including international borders, such as is the case with Venezuela. In that country, especially for EEV, municipalities in the department of Cesar are bordering and at risk for that arboviral infection. there is a high risk of equine encephalitis outbreaks, especially for VEE. This poses a risk also, for municipalities in the department of Cesar, bordering with Venezuela.

Inference for a spatio-temporal model with partial spatial data: African horse sickness virus in Morocco

African horse sickness virus (AHSV) is a vector-borne virus spread by midges (Culicoides spp.). The virus causes African horse sickness (AHS) disease in some species of equid. AHS is endemic in parts of Africa, previously emerged in Europe and in 2020 caused outbreaks for the first time in parts of Eastern Asia. Here we analyse a unique historic dataset from the 1989–1991 emergence of AHS in Morocco in a naïve population of equids. Sequential Monte Carlo and Markov chain Monte Carlo techniques are used to estimate parameters for a spatial–temporal model using a transmission kernel. These parameters allow us to observe how the transmissibility of AHSV changes according to the distance between premises. We observe how the spatial specificity of the dataset giving the locations of premises on which any infected equids were reported affects parameter estimates. Estimations of transmissibility were similar at the scales of village (location to the nearest 1.3 km) and region (median area 99 km2), but not province (median area 3000 km2). This data-driven result could help inform decisions by policy makers on collecting data during future equine disease outbreaks, as well as policies for AHS control.

Active Circulation of Madariaga Virus, a Member of the Eastern Equine Encephalitis Virus Complex, in Northeast Brazil.

Madariaga virus (MADV) is a member of the eastern equine encephalitis virus (EEEV) complex that circulates in Central and South America. It is a zoonotic, mosquito-borne pathogen, belonging to the family Togaviridae. Disturbances in the natural transmission cycle of this virus result in outbreaks in equines and humans, leading to high case fatality in the former and acute febrile illness or neurological disease in the latter. Although a considerable amount of knowledge exists on the eco-epidemiology of North American EEEV strains, little is known about MADV. In Brazil, the most recent isolations of MADV occurred in 2009 in the States of Paraíba and Ceará, northeast Brazil. Because of that, health authorities have recommended vaccination of animals in these regions. However, in 2019 an equine encephalitis outbreak was reported in a municipality in Ceará. Here, we present the isolation of MADV from two horses that died in this outbreak. The full-length genome of these viruses was sequenced, and phylogenetic analyses performed. Pathological findings from postmortem examination are also discussed. We conclude that MADV is actively circulating in northeast Brazil despite vaccination programs, and call attention to this arbovirus that likely represents an emerging pathogen in Latin America.

Pathogenesis of Two Western Mediterranean West Nile Virus Lineage 1 Isolates in Experimentally Infected Red-Legged Partridges (Alectoris rufa).

West Nile virus (WNV) is the most widespread flavivirus in the world with a wide vertebrate host range. Its geographic expansion and activity continue to increase with important human and equine outbreaks and local bird mortality. In a previous experiment, we demonstrated the susceptibility of 7-week-old red-legged partridges (Alectoris rufa) to Mediterranean WNV isolates Morocco/2003 and Spain/2007, which varied in virulence for this gallinaceous species. Here we study the pathogenesis of the infection with these two strains to explain the different course of infection and mortality. Day six post-inoculation was critical in the course of infection, with the highest viral load in tissues, the most widespread virus antigen, and more severe lesions. The most affected organs were the heart, liver, and spleen. Comparing infections with Morocco/2003 and Spain/2007, differences were observed in the viral load, virus antigen distribution, and lesion nature and severity. A more acute and marked inflammatory reaction (characterized by participation of microglia and CD3+ T cells) as well as neuronal necrosis in the brain were observed in partridges infected with Morocco/2003 as compared to those infected with Spain/2007. This suggests a higher neurovirulence of Morocco/2003, probably related to one or more specific molecular determinants of virulence different from Spain/2007.

Information-Seeking Preferences of the Colorado Equine Industry for Distribution of Disease Outbreak Information

The purpose of this study was to learn how perceptions of accuracy and availability of sources affect how members of the Colorado equine industry seek both everyday information and information during an equine disease outbreak. A survey was distributed by email and social media to members of Colorado-based equine organizations. A total of 256 survey responses were obtained from individuals representing a spectrum of ages and roles in the Colorado equine industry. Survey participants predominantly identified as female (95.3%) and their industry role as a horse owner (41%) or a competitive (25.8%) or pleasure (13.3%) rider. Younger survey participants reported greater (P < .0001) use of social media, and both participant age (P < .015) and information source (P < .0001) affected the perception of resource accuracy. In the event of an equine disease outbreak, industry role was an important factor (P = .003) in the selection of news sources, whereas age was not (P = .19). Many participants (56%) identified disease symptoms/signs to be the most important information to be sought during a disease outbreak and most (69.9%) preferred state or veterinary resources for this information. The identification of why Colorado equine industry members access information from specific sources may guide animal health and extension professionals to tailor their online presence to best meet the communication needs of the Colorado equine industry.

Development of a multilocus sequence typing scheme for Rhodococcus equi

Rhodococcus equi causes pulmonary and extrapulmonary infections in animals and humans, with endemic situations and significant young foal mortality in stud farms worldwide. Despite its economic impact in the horse-breeding industry, the broad geographic and host distribution, global diversity and population structure of R. equi remain poorly characterised. In this context, we developed a multilocus sequence typing (MLST) scheme using 89 clinical and environmental R. equi of various origins and eight Rhodococcus sp. Data can be accessed at http://pubmlst.org/rhodococcus/. A clonal R. equi population was observed with 16 out of 37 sequence types (STs) grouped into six clonal complexes (CC) based on single-locus variants. One of the six CCs (CC3) is not host-specific, suggesting potential exchanges between different R. equi reservoirs. Most of the virulent equine R. equi CCs/unlinked STs were plasmid-type-specific. Despite this, marked genetic variability with the circulation of multiple R. equi genotypes was generally observed even within the same animal. Focusing on outbreaks, data indicated (i) the potential contagious transmission of R. equi during the 2012-Mayotte equine outbreak because of the poor genotype diversity of clinical strains; (ii) a potential porcine outbreak among the 30 Belgian farms investigated in 2013. This first Rhodococcus equi MLST is a powerful tool for further epidemiological investigations and population biology studies of R. equi isolates.

Human transcriptome response to immunization with live-attenuated Venezuelan equine encephalitis virus vaccine (TC-83): Analysis of whole blood

ABSTRACTVenezuelan equine encephalitis virus (VEEV) is an important human and animal alphavirus pathogen transmitted by mosquitoes. The virus is endemic in Central and South America, but has also caused equine outbreaks in southwestern areas of the United States. In an effort to better understand the molecular mechanisms of the development of immunity to this important pathogen, we performed transcriptional analysis from whole, unfractionated human blood of patients who had been immunized with the live-attenuated vaccine strain of VEEV, TC-83. We compared changes in the transcriptome between naïve individuals who were mock vaccinated with saline to responses of individuals who received TC-83. Significant transcriptional changes were noted at days 2, 7, and 14 following vaccination. The top canonical pathways revealed at early and intermediate time points (days 2 and 7) included the involvement of the classic interferon response, interferon-response factors, activation of pattern recognition receptors, and engagement of the inflammasome. By day 14, the top canonical pathways included oxidative phosphorylation, the protein ubiquitination pathway, natural killer cell signaling, and B-cell development. Biomarkers were identified that differentiate between vaccinees and control subjects, at early, intermediate, and late stages of the development of immunity as well as markers which were common to all 3 stages following vaccination but distinct from the sham-vaccinated control subjects. The study represents a novel examination of molecular processes that lead to the development of immunity against VEEV in humans and which may be of value as diagnostic targets, to enhance modern vaccine design, or molecular correlates of protection.

Protection against henipaviruses in swine requires both, cell-mediated and humoral immune response

Hendra virus (HeV) and Nipah virus (NiV) are members of the genus Henipavirus, within the family Paramyxoviridae. Nipah virus has caused outbreaks of human disease in Bangladesh, Malaysia, Singapore, India and Philippines, in addition to a large outbreak in swine in Malaysia in 1998/1999. Recently, NiV was suspected to be a causative agent of an outbreak in horses in 2014 in the Philippines, while HeV has caused multiple human and equine outbreaks in Australia since 1994. A swine vaccine able to prevent shedding of infectious virus is of veterinary and human health importance, and correlates of protection against henipavirus infection in swine need to be better understood. In the present study, three groups of animals were employed. Pigs vaccinated with adjuvanted recombinant soluble HeV G protein (sGHEV) and challenged with HeV, developed antibody levels considered to be protective prior to the challenge (titers of 320). However, activation of the cell-mediated immune response was not detected, and the animals were only partially protected against challenge with 5×105 PFU of HeV per animal. In the second group, cross-neutralizing antibody levels against NiV in the sGHEV vaccinated animals did not reach protective levels, and with no activation of cellular immune memory, these animals were not protected against NiV. Only pigs orally infected with 5×104 PFU of NiV per animal were protected against nasal challenge with 5×105 PFU of NiV per animal. This group of pigs developed protective antibody levels, as well as cell-mediated immune memory. Peripheral blood mononuclear cells restimulated with UV-inactivated NiV upregulated IFN-gamma, IL-10 and the CD25 activation marker on CD4+CD8+ T memory helper cells and to lesser extent on CD4−CD8+ T cells. In conclusion, both humoral and cellular immune responses were required for protection of swine against henipaviruses.

Serological investigation of equine respiratory outbreaks at a racetrack in Ontario, Canada (2011-2015)

Serological investigation of equine respiratory outbreaks at a racetrack in Ontario, Canada (2011-2015)

West Nile Disease Epidemiology in North-West Africa: Bibliographical Review.

West Nile fever (WNF) or West Nile disease (WND) is a mosquito-borne viral disease that can affect birds, humans and horses. West Nile virus (WNV) is a member of the genus Flavivirus in the family Flaviviridae. WNV is maintained in a mosquito-bird-mosquito transmission cycle, whereas humans and horses are considered dead-end hosts. In human and horses, symptoms range from unapparent infection to mild febrile illness, meningitis, encephalitis or death. WNV has a wide geographical range that includes portions of Europe, Asia, Africa, Australia (Kunjin virus), and in North, Central and South America. Migratory birds are thought to be primarily responsible for virus dispersal, including reintroduction of WNV from endemic areas into regions that experience sporadic outbreaks (Fields Virology, 2001, Lippincott Williams and Wilkins, Philadelphia, Pennsylvania, USA, 1043-1125). The occurrence of disease in humans and animals along with birds and mosquitoes surveillance for WNV activity demonstrates that the virus range has dramatically expanded including North, Central and South America as well as Europe and countries facing the Mediterranean Basin. WND infection in humans has been reported in Morocco in 1996 (Virologie, 1, 1997, 248), in Tunisia in 2007 (Ann. N. Y. Acad., 951, 2001, 117) (Med. Trop., 61, 2001, 487) and 2003 (Epidémiologie de la fièvre West Nile, 2012, Thèse de doctorat, Université Montpellier II, Sciences et techniques du Langueduc, Montpellier, France), and in Algeria in 1994 (Rev. Sci. Tech., 31, 2012, 829). Outbreaks of equine encephalitis have been also reported in Morocco in 1996 (Bull. OIE, 11, 1996, 867), in 2003 (Emerg. Infect. Dis., 11, 2005, 306) and in 2010 (World Animal Health Information Database. WAHID, 2010). Serological evidence of WNV has been demonstrated in the three countries in many species. The aim of this review was to assess the epidemiological situation of WND in north-west Africa comprising Morocco, Algeria and Tunisia, with an updated literature review based on of human cases and equine outbreaks reports as well as serological studies in these countries.

Ecological Niche Modelling of Potential West Nile Virus Vector Mosquito Species and Their Geographical Association with Equine Epizootics in Italy

In Italy, West Nile virus (WNV) equine outbreaks have occurred annually since 2008. Characterizing WNV vector habitat requirements allows for the identification of areas at risk of viral amplification and transmission. Maxent-based ecological niche models were developed using literature records of 13 potential WNV Italian vector mosquito species to predict their habitat suitability range and to investigate possible geographical associations with WNV equine outbreak occurrence in Italy from 2008 to 2010. The contribution of different environmental variables to the niche models was also assessed. Suitable habitats for Culex pipiens, Aedes albopictus, and Anopheles maculipennis were widely distributed; Culex modestus, Ochlerotatus geniculatus, Ochlerotatus caspius, Coquillettidia richiardii, Aedes vexans, and Anopheles plumbeus were concentrated in north-central Italy; Aedes cinereus, Culex theileri, Ochlerotatus dorsalis, and Culiseta longiareolata were restricted to coastal/southern areas. Elevation, temperature, and precipitation variables showed the highest predictive power. Host population and landscape variables provided minor contributions. WNV equine outbreaks had a significantly higher probability to occur in habitats suitable for Cx. modestus and Cx. pipiens, providing circumstantial evidence that the potential distribution of these two species coincides geographically with the observed distribution of the disease in equines.

West Nile Virus outbreak in Sardinia, Italy, in 2011

West Nile Virus (WNV) is an enveloped, positive-sense RNA virus belonging to the genus Flavivirus, antigenically related to the Japanese encephalitis complex in the family Flaviviridae. The principal vectors are mosquitoes, in particular Culex spp, and virus amplification seems to occur in susceptible birds that are the principal vertebrate reservoir hosts, whereas humans, horses and other vertebrates are considered incidental or dead-end hosts. The first Italian equine outbreak was reported in late summer of 1998 in Tuscany, in the area surrounding the Fucecchio marshes, where 14 clinical cases of WND in housed equines were recorded. In 2011 WNV appeared for the first time in Sardinia, representing the first clinical cases in equines in Italy in 2011. The outbreak occurred both in humans and in equines. The serological survey performed on 253 equines living in the province of Oristano detected a total of 87 IgG-positive subjects. Among them, 46 horses showed neurological signs such as ataxia, paresis, paralysis, hyperesthesia, muscle fasciculations, seizures, or fever. Nine of them died or were euthanized. In forthcoming years, surveillance of wild birds and insects will be used to forecast the extension and spread of WNV. The information gathered will be used to direct or optimise strategies intended to prevent virus transmission.

Comparison of different trapping methods for surveillance of mosquito vectors of West Nile virus in Rhône Delta, France

Five trapping methods were compared for monitoring potential vectors of the West Nile virus in four areas in the Camargue Plain of France: carbon dioxide traps, bird-baited traps, gravid traps, resting boxes, and human landing catches. A total of 73,721 specimens, representing 14 species, was trapped in 2006. Results showed significant differences in species and abundance between the type of traps. Many more specimens were collected using CO(2) traps than any other method, with an average of 212 specimens per night per trap (p<0.05). Culex pipiens was the most abundant species collected (36.8% of total with CO(2) traps), followed by Aedes caspius (22.7%), Anopheles hyrcanus (18.3%), Culex modestus (18.3%), and Aedes detritus (3.2%). Bird-baited traps captured only eight specimens per night per trap on average, mainly Cx. pipiens (89.9%). The species collected and their abundance are influenced by the trap location, at ground or canopy level. Culex pipiens was twice as abundant in the canopy as on the ground, whereas it was the opposite for Ae. caspius, An. hyrcanus, and Ae. detritus. Culex modestus was equally abundant at both levels. Resting boxes and gravid traps were much less efficient, capturing around 0.3 specimens per night per trap. Results are discussed in relation to West Nile virus surveillance.

Evaluation of Recombinant Proteins of Burkholderia mallei for Serodiagnosis of Glanders

Glanders is a contagious disease caused by the Gram-negative bacillus Burkholderia mallei. The number of equine glanders outbreaks has increased steadily during the last decade. The disease must be reported to the Office International des Epizooties, Paris, France. Glanders serodiagnosis is hampered by the considerable number of false positives and negatives of the internationally prescribed tests. The major problem leading to the low sensitivity and specificity of the complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA) has been linked to the test antigens currently used, i.e., crude preparations of whole cells. False-positive results obtained from other diagnostic tests utilizing crude antigens lead to financial losses to animal owners, and false-negative results can turn a risk into a possible threat. In this study, we report on the identification of diagnostic targets using bioinformatics tools for serodiagnosis of glanders. The identified gene sequences were cloned and expressed as recombinant proteins. The purified recombinant proteins of B. mallei were used in an indirect ELISA format for serodiagnosis of glanders. Two recombinant proteins, 0375H and 0375TH, exhibited 100% sensitivity and specificity for glanders diagnosis. The proteins also did not cross-react with sera from patients with the closely related disease melioidosis. The results of this investigation highlight the potential of recombinant 0375H and 0375TH proteins in specific and sensitive diagnosis of glanders.

Eastern Equine Encephalitis in Tennessee: 2002–2008

Human and equine outbreaks caused by eastern equine encephalomyelitis virus (EEEV) typically occur in North America adjacent to coastal wetlands associated with the presence of Culiseta melanura (Coquillet) mosquitoes. Eastern equine encephalomyelitis (EEE) is an emerging disease in Tennessee, as the first records of equine disease began in 2002. In 2006 we trapped and tested mosquitoes for EEEV at hardwood swamps in western Tennessee that were at the epicenter of a multi-equine outbreak in fall of 2005. Additionally, the Tennessee Valley Authority tested mosquito pools collected in Tennessee swamps from 2000 to 2007 for the presence of arboviruses. Two pools of EEEV positive Culex erraticus (Dyer and Knab) mosquitoes were found (one each in 2003 and 2004) in a county adjacent to where the 2005 outbreak occurred. In 2008, another EEE outbreak involving multiple horses occurred in West Tennessee. A brain specimen was collected from a horse during this outbreak and the first isolate of EEEV from Tennessee was obtained. In total, 74,531 mosquitoes collected from 2000 to 2008 were tested via polymerase chain reaction and VecTest for EEEV. The traditional enzootic vector, Cs. melanura, was found in low numbers at all collection sites. Cx. erraticus, however, was consistently found in high numbers and was the only mosquito species in which EEEV was detected. We suggest that EEE transmission may be maintained by Cx. erraticus in a nontraditional cycle. We discuss the importance of a nontraditional cycle from the perspective of EEEV adaptation and emergence.

Le virus West Nile: diagnostic, surveillance et évolution épidémiologique en Europe

West Nile virus is an arbovirus affecting horses and humans, highly susceptible incidental and deadend hosts. Its presence in Europe is not new, as West Nile virus infections were first reported in the 1960’ s : at the time, human and equine cases had already been described in France in the Camargue region. After 30 years without any reported outbreak, West Nile virus re-emerged in Europe at the end of the 90’ s with limited (Czech Republic 1997, Italy 1998, France 2000) or large-scale sporadic outbreaks (Romania 1996, Russia 1999). More recently, a resurgence of WNV has been observed since 2008, probably related to changes in the multiple viral strains present in Europe, and in ecological and climatic conditions favourable to the multiplication of vector mosquitoes. This resurgence peaked in 2010, with unprecedented numbers of equine outbreaks and human cases in numerous countries in Europe, particularly in the Mediterranean basin : 8 countries (Bulgaria, Spain, Greece, Hungary, Italy, Portugal, Romania and Russia) were affected, with large-scale foci in Greece and Russia. Even though an equine vaccine is available in Europe since 2009, the control of West Nile Virus infection still relies heavily on reinforced surveillance of neurological conditions in humans and horses.