West Nile virus (WNV) is an arthropod-borne virus primarily transmitted by Culex mosquitoes, among birds, but occasionally infecting humans and equids. Understanding environmental factors on the disease occurrence is crucial for planning effective prevention and control strategies. Our study estimates the short-term effects of ambient temperature, relative humidity and precipitation on weekly cases of WNV in equids in Spain, using a space-time stratified case-crossover design. Because WNV transmission occurs sometime after the weather conditions become favorable for the vector, we aimed to estimate the lagged effect of the three weather variables on the incidence of WNV cases in equids. Therefore, we applied a conditional Poisson regression within the framework of lag-distributed models. These models are particularly effective for examining the delayed effects of exposures. The incidence of WNV confirmed cases was associated with temperatures registered within the prior two and eight weeks. The highest incidence was observed at lag four, where the incident rate ratio (IRR) increased to 11.96 (95 % CI: 9.84-50.40) with mean temperature at 33 °C, likewise relative humidity effect peaked also at lag four (IRR=3.99; 95 % CI: 1.43-11.16) at 93 % of relative humidity. On the other hand, the confidence intervals for precipitation were very wide, making it difficult to discern a clear change in the risk of WNV infection associated with total precipitation. This study sheds light on the complex relationships between meteorological variables and the incidence of WNV cases. Considering the zoonotic nature of the disease, these results could provide valuable information for surveillance and early warning of the disease.
- Klíčová slova
- Case-crossover design, Distributed lag non-linear models, Equids, Precipitation, Relative humidity, Temperature, West Nile virus,
- MeSH
- Equidae * virologie MeSH
- incidence MeSH
- klinické křížové studie MeSH
- koně MeSH
- nemoci koní * epidemiologie virologie MeSH
- počasí * MeSH
- teplota MeSH
- virus západního Nilu izolace a purifikace MeSH
- vlhkost MeSH
- západonilská horečka * epidemiologie veterinární MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Španělsko epidemiologie MeSH
The emergence of West Nile virus (WNV) and Usutu virus (USUV) in addition to the autochthonous tick-borne encephalitis virus (TBEV) in Europe causes rising concern for public and animal health. The first equine case of West Nile neuroinvasive disease in Austria was diagnosed in 2016. As a consequence, a cross-sectional seroprevalence study was conducted in 2017, including 348 equids from eastern Austria. Serum samples reactive by ELISA for either flavivirus immunoglobulin G or M were further analyzed with the plaque reduction neutralization test (PRNT-80) to identify the specific etiologic agent. Neutralizing antibody prevalences excluding vaccinated equids were found to be 5.3% for WNV, 15.5% for TBEV, 0% for USUV, and 1.2% for WNV from autochthonous origin. Additionally, reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed to detect WNV nucleic acid in horse sera and was found to be negative in all cases. Risk factor analysis did not identify any factors significantly associated with seropositivity.
- Klíčová slova
- Austria, Usutu virus, West Nile virus, epidemiology, flavivirus, horses, seroprevalence, tick-borne encephalitis virus,
- MeSH
- endemické nemoci veterinární MeSH
- Equidae virologie MeSH
- Flavivirus imunologie MeSH
- infekce viry z rodu Flavivirus epidemiologie veterinární MeSH
- klíšťová encefalitida epidemiologie veterinární MeSH
- koně MeSH
- nemoci koní epidemiologie MeSH
- protilátky virové krev MeSH
- průřezové studie MeSH
- rizikové faktory MeSH
- séroepidemiologické studie MeSH
- virus západního Nilu imunologie MeSH
- viry klíšťové encefalitidy imunologie MeSH
- západonilská horečka epidemiologie veterinární MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Rakousko epidemiologie MeSH
- Názvy látek
- protilátky virové MeSH
BackgroundDespite the known circulation of West Nile virus (WNV) and Usutu virus (USUV) in Slovakia, no formal entomological surveillance programme has been established there thus far.AimTo conduct contemporaneous surveillance of WNV and USUV in different areas of Slovakia and to assess the geographical spread of these viruses through mosquito vectors. The first autochthonous human WNV infection in the country is also described.MethodsMosquitoes were trapped in four Slovak territorial units in 2018 and 2019. Species were characterised morphologically and mosquito pools screened for WNV and USUV by real-time reverse-transcription PCRs. In pools with any of the two viruses detected, presence of pipiens complex group mosquitoes was verified using molecular approaches.ResultsAltogether, 421 pools containing in total 4,508 mosquitoes were screened. Three pools tested positive for WNV and 16 for USUV. USUV was more prevalent than WNV, with a broader spectrum of vectors and was detected over a longer period (June-October vs August for WNV). The main vectors of both viruses were Culex pipiens sensu lato. Importantly, WNV and USUV were identified in a highly urbanised area of Bratislava city, Slovakias' capital city. Moreover, in early September 2019, a patient, who had been bitten by mosquitoes in south-western Slovakia and who had not travelled abroad, was laboratory-confirmed with WNV infection.ConclusionThe entomological survey results and case report increase current understanding of the WNV and USUV situation in Slovakia. They underline the importance of vector surveillance to assess public health risks posed by these viruses.
- Klíčová slova
- Europe, Slovakia, Usutu, West Nile, arbovirus, flavivirus, mosquitoes,
- MeSH
- Culex * MeSH
- Culicidae * MeSH
- Flavivirus * genetika MeSH
- lidé MeSH
- virus západního Nilu * genetika MeSH
- západonilská horečka * diagnóza epidemiologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
- Geografické názvy
- Slovenská republika epidemiologie MeSH
Monitoring infectious diseases is a crucial part of preventive veterinary medicine in zoological collections. This zoo environment contains a great variety of animal species that are in contact with wildlife species as a potential source of infectious diseases. Wild birds may be a source of West Nile virus (WNV) and Usutu (USUV) virus, which are both emerging pathogens of rising concern. The aim of this study was to use zoo animals as sentinels for the early detection of WNV and USUV in Slovenia. In total, 501 sera from 261 animals of 84 animal species (including birds, rodents, lagomorphs, carnivores, ungulates, reptiles, equids, and primates) collected for 17 years (2002-2018) were tested for antibodies to WNV and USUV. Antibodies to WNV were detected by indirect immunofluorescence tests in 16 (6.1%) of 261 animals representing 10 species, which were sampled prior to the first active cases of WNV described in 2018 in Slovenia in humans, a horse, and a hooded crow (Corvus cornix). Antibodies to USUV were detected in 14 out of 261 animals tested (5.4%) that were positive prior to the first positive cases of USUV infection in common blackbirds (Turdus merula) in Slovenia. The study illustrates the value of zoological collections as a predictor of future emerging diseases.
- Klíčová slova
- Usutu virus epidemiology, West Nile virus, biosurveillance, infectious diseases, zoo environment,
- MeSH
- Flavivirus imunologie MeSH
- infekce viry z rodu Flavivirus krev diagnóza epidemiologie imunologie MeSH
- neutralizující protilátky krev MeSH
- protilátky virové krev MeSH
- virus západního Nilu imunologie MeSH
- západonilská horečka krev diagnóza epidemiologie imunologie MeSH
- zvířata v ZOO klasifikace virologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Slovinsko epidemiologie MeSH
- Názvy látek
- neutralizující protilátky MeSH
- protilátky virové MeSH
West Nile virus lineage 2 (WNV-2) was detected in the brain of 17 goshawks (Accipiter gentilis) that succumbed to neuroinvasive disease in the Czech Republic during 2018: twelve birds were captive and five wild. Furthermore, two wild sparrowhawks (Accipiter nisus) and three other captive birds of prey (golden eagle Aquila chrysaetos, hybrid saker falcon Falco cherrug × F. rusticolus and Harris's hawk Parabuteo unicinctus) also died due to WNV encephalitis. The 2018 outbreak in Czech raptors clearly reflects a new epidemiological situation and indicates an increasing risk of both raptor and human infection with WNV-2 in the country.
- Klíčová slova
- Accipiter gentilis, Czechland, Flavivirus, West Nile virus mortality, goshawk, raptors,
- MeSH
- epidemický výskyt choroby * MeSH
- některé rody čeledi Accipitridae mikrobiologie MeSH
- nemoci ptáků epidemiologie virologie MeSH
- veřejné zdravotnictví MeSH
- virus západního Nilu genetika MeSH
- západonilská horečka epidemiologie veterinární MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika epidemiologie MeSH
Monitoring West Nile virus (WNV) and Usutu virus (USUV) activity now has the highest priority among mosquito-borne pathogenic viruses circulating in the European Union. This study documents a first time detection and the co-circulation of WNV lineage-2 (with the minimal prevalence of 0.46%) and USUV clade Europe 2 (with the minimal prevalence of 0.25%) in mosquitoes from the same habitat of south-western Slovakia and underlines necessity to perform rigorous surveillance in birds, mosquitoes, horses and humans in that country.
- Klíčová slova
- Culex spp., Usutu virus, West Nile fever, West Nile virus, mosquitoes, surveillance,
- MeSH
- Culex virologie MeSH
- Culicidae virologie MeSH
- ekosystém MeSH
- Flavivirus genetika izolace a purifikace MeSH
- fylogeneze MeSH
- infekce viry z rodu Flavivirus epidemiologie veterinární MeSH
- komáří přenašeči virologie MeSH
- koně virologie MeSH
- lidé MeSH
- prevalence MeSH
- ptáci virologie MeSH
- veřejné zdravotnictví MeSH
- virus západního Nilu genetika izolace a purifikace MeSH
- západonilská horečka epidemiologie veterinární MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Slovenská republika epidemiologie MeSH
Here we report the first detection of lineage 2 of neuroinvasive West Nile virus (WNV-2) in mosquitoes collected in a fishpond area of the Trebon Basin in southern Bohemia during the 2018 mosquito season. A total of 6790 mosquito females belonging to the Culex modestus, Culex pipiens, and Coquillettidia richiardii species were investigated in 136 pools, and WNV RNA was detected in two of them. The WNV strain shares genetic homology with other WNV-2 strains isolated in southern Moravia as well as with those causing outbreaks in southern and central Europe. The results highlight the need for entomological surveillance of pathogenic arboviruses even in areas not yet affected (WNV-free areas). The South Bohemian Region (in addition to southern Moravia) is becoming another risk zone of autochthonous occurrence of West Nile fever in the Czech Republic.
- Klíčová slova
- Coquillettidia richiardii, Culex modestus, Culex pipiens, South Bohemia, West Nile virus, arboviruses, emerging zoonoses, mosquitoes,
- MeSH
- Culicidae * virologie MeSH
- virus západního Nilu * klasifikace fyziologie MeSH
- západonilská horečka * epidemiologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika epidemiologie MeSH
AIM: To analyse repeated detection of West Nile virus (WNV) in mosquitoes in South Moravia in correlation with the first documented autochthonous human cases of West Nile fever (WNF), focusing on epidemiological and environmental investigation. MATERIALS AND METHODS: Here we report case studies of five patients with autochthonous WNF without any travel history diagnosed in South Moravia in 2018, along with in-depth epidemiological and environmental investigation. The cases were classified as confirmed based on the case definition criteria established in Commission Implementing Decision (EU) 2018/945. RESULTS: Between July and September 2018, a total of five human cases of West Nile virus infection were suspected and subsequently confirmed by the National Reference Laboratory for Arboviruses in Ostrava. All mosquito suspensions from the area where the first case of WNV infection was diagnosed tested WNV negative. CONCLUSIONS: WNV circulation in South Moravia has been known since 1997 when the first human cases (probably caused by WNV lineage 1) were confirmed after floods. The presence of more serious neuroinvasive lineage 2 (WNV-2), now circulating in central and eastern Europe, was detected repeatedly in 2013, 2015, and 2016 in Cx. modestus and Cx. pipiens mosquitoes within the scope of targeted entomological surveillance. These findings were published in 2016-2018 in both the professional press and mass media. It was only a matter of time and of making the correct differential diagnosis in patients with non-specific neuroinfections before there were confirmed autochthonous human cases of WNF caused by WNV-2. These presumptions were corroborated by epidemiological investigations performed by the staff of the Regional Public Health Authority of the South Moravian Region and Academy of Sciences.
- Klíčová slova
- West Nile fever (WNF), West Nile virus (WNV), epidemiological investigation, neuroinfections,
- MeSH
- cestování MeSH
- Culicidae * virologie MeSH
- lidé MeSH
- virus západního Nilu * fyziologie MeSH
- západonilská horečka * diagnóza epidemiologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika epidemiologie MeSH
OBJECTIVE: The aim of the study was to evaluate the seroprevalence of West Nile virus (WNV) among the variable population of Eastern Slovakia. METHODS: A serologic survey was conducted using 464 serum samples. The basic demographic, epidemiologic and clinical information was obtained for each serum sample at the time of specimen collection. The presence of antibodies against WNV was investigated using a commercial enzyme-linked immunosorbent assay (ELISA). All the ELISA positive samples were further analysed by a neutralization test with WNV and Usutu virus. RESULTS: Three serum samples (0.65%) from the participants (N = 464) were considered positive for antibodies to WNV. A 29-year-old female was repeatedly exposed to mosquito bites working as a shepherdess and participating in many outdoor activities. Two other females (61 and 76 years old) were treated at the Department of Neurology due to monoparesis of the upper extremity, vertigo; both had a significant epidemiological history with frequent tick and mosquito bites and stay in an endemic region. CONCLUSIONS: Although there was no evidence of WNV infection in the Slovak Republic, the epidemiological situation in the neighbouring countries warrants vigilance and appropriate measures, including the introduction of specific diagnostic tools into clinical practice. The constant monitoring of birds and mosquitoes also seems necessary.
- Klíčová slova
- West Nile virus, mosquitoes, seroprevalence,
- MeSH
- Culicidae MeSH
- ELISA MeSH
- protilátky virové MeSH
- séroepidemiologické studie MeSH
- virus západního Nilu izolace a purifikace MeSH
- západonilská horečka diagnóza epidemiologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Slovenská republika epidemiologie MeSH
- Názvy látek
- protilátky virové MeSH
BACKGROUND: West Nile virus (WNV) is currently the most important mosquito-borne pathogen spreading in Europe. Data on overwintering of WNV in mosquitoes are crucial for understanding WNV circulation in Europe; nonetheless, such data were not available so far. RESULTS: A total of 28,287 hibernating mosquitoes [27,872 Culex pipiens, 73 Anopheles maculipennis (sensu lato), and 342 Culiseta annulata], caught in February or March between 2011 and 2017 in a WNV-endemic region of South Moravia, Czech Republic, were screened for the presence of WNV RNA. No WNV positive pools were found from 2011 to 2016, while lineage 2 WNV RNA was detected in three pools of Culex pipens mosquitoes collected in 2017 at two study sites. CONCLUSIONS: To the best of our knowledge, this is the first record of WNV RNA in overwintering mosquitoes in Europe. The data support the hypothesis of WNV persistence in mosquitoes throughout the winter season in Europe.
- Klíčová slova
- Anopheles maculipennis, Culex pipiens, Culiseta annulata, Czech Republic, Flavivirus, Hibernation, Overwintering, West Nile fever, West Nile virus,
- MeSH
- Culicidae virologie MeSH
- hmyz - vektory virologie MeSH
- lidé MeSH
- roční období MeSH
- virus západního Nilu genetika izolace a purifikace fyziologie MeSH
- západonilská horečka epidemiologie přenos virologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Evropa epidemiologie MeSH
