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Frontiers in Cellular and Infection... 2023In Spain, the largest human West Nile virus (WNV) outbreak among humans was reported in 2020, constituting the second most important outbreak in Europe that season....
In Spain, the largest human West Nile virus (WNV) outbreak among humans was reported in 2020, constituting the second most important outbreak in Europe that season. Extremadura (southwestern Spain) was one of the affected areas, reporting six human cases. The first autochthonous human case in Spain was reported in Extremadura in 2004, and no other human cases were reported until 2020. In this work, we describe the first WNV human outbreak registered in Extremadura, focusing on the most important clinical aspects, diagnostic results, and control actions which followed. In 2020, from September to October, human WNV infections were diagnosed using a combination of molecular and serological methods (an in-house specific qRT-PCR and a commercial ELISA for anti-WNV IgM and IgG antibodies) and by analysing serum, urine, and/or cerebrospinal fluid samples. Serological positive serum samples were further tested using commercial kits against related flaviviruses Usutu and Tick-borne encephalitis in order to analyse serological reactivity and to confirm the results by neutralisation assays. In total, six cases of WNV infection (five with neuroinvasive disease and one with fever) were identified. Clinical presentation and laboratory findings are described. No viral RNA was detected in any of the analysed samples, but serological cross-reactivity was detected against the other tested flaviviruses. Molecular and serological methods for WNV detection in various samples as well as differential diagnosis are recommended. The largest number of human cases of WNV infection ever registered in Extremadura, Spain, occurred in 2020 in areas where circulation of WNV and other flaviviruses has been previously reported in humans and animals. Therefore, it is necessary to enhance surveillance not only for the early detection and implementation of response measures for WNV but also for other emerging flaviviruses that could be endemic in this area.
Topics: Animals; Humans; West Nile virus; West Nile Fever; Spain; Flavivirus; Antibodies, Viral
PubMed: 37469597
DOI: 10.3389/fcimb.2023.1155867 -
Veterinaria Italiana Dec 2022West Nile virus (WNV) is an emerging arbovirus which affects humans and horses. A cross sectional study was carried out on 106 local horses in Kaduna and 78 domestic...
West Nile virus (WNV) is an emerging arbovirus which affects humans and horses. A cross sectional study was carried out on 106 local horses in Kaduna and 78 domestic chickens in Federal Capital Territory. A total of 184 sera were screened for West Nile virus anti Pr‑E antibodies using ID Screen® West Nile competitive enzyme linked immunosorbent assay. For the horses, an overall prevalence of 92.45% was recorded while domestic chickens had a preponderance of 7.69%. From our study, there was a statistical significant difference between the occurrences of WNV in stallions than mares with p < 0.05. Comparing the occurrence of West Nile virus between species, horses were more likely to be infected by West Nile virus than domestic chickens (OR 147). This is the first seroprevalence study investigating West Nile virus infection in domestic chickens in Nigeria. The presence of the antibodies indicates the widespread circulation and the potential risk of infection in humans and animals. In order to understand the epidemiology of West Nile virus infection in Nigeria, there is need for surveillance to be implemented in human and animal sectors.
Topics: Humans; Animals; Horses; Female; Male; West Nile virus; West Nile Fever; Nigeria; Chickens; Cross-Sectional Studies; Seroepidemiologic Studies; Antibodies, Viral; Horse Diseases
PubMed: 37219829
DOI: 10.12834/VetIt.2596.16323.2 -
Viruses Mar 2022West Nile virus lineage 2 (WNV-L2) emerged in Europe in 2004; since then, it has spread across the continent, causing outbreaks in humans and animals. During 2017 and...
West Nile virus lineage 2 (WNV-L2) emerged in Europe in 2004; since then, it has spread across the continent, causing outbreaks in humans and animals. During 2017 and 2020, WNV-L2 was detected and isolated from four northern goshawks in two provinces of Catalonia (north-eastern Spain). In order to characterise the first Spanish WNV-L2 isolates and elucidate the potential overwintering of the virus in this Mediterranean region, complete genome sequencing, phylogenetic analyses, and a study of phenotypic characterisation were performed. Our results showed that these Spanish isolates belonged to the central-southern WNV-L2 clade. In more detail, they were related to the Lombardy cluster that emerged in Italy in 2013 and has been able to spread westwards, causing outbreaks in France (2018) and Spain (2017 and 2020). Phenotypic characterisation performed in vitro showed that these isolates presented characteristics corresponding to strains of moderate to high virulence. All these findings evidence that these WNV-L2 strains have been able to circulate and overwinter in the region, and are pathogenic, at least in northern goshawks, which seem to be very susceptible to WNV infection and may be good indicators of WNV-L2 circulation. Due to the increasing number of human and animal cases in Europe in the last years, this zoonotic flavivirus should be kept under extensive surveillance, following a One-Health approach.
Topics: Animals; Europe; Phylogeny; Spain; West Nile Fever; West Nile virus
PubMed: 35336976
DOI: 10.3390/v14030569 -
Viruses May 2021West Nile virus (WNV) has never been reported from Lebanon. Yet, this country is located on the flyway of migratory birds in the Middle East region. Serological...
West Nile virus (WNV) has never been reported from Lebanon. Yet, this country is located on the flyway of migratory birds in the Middle East region. Serological screening was conducted to assess the potential circulation of this virus. Human, horse, and chicken sera were collected from the Bekaa and North districts. Specific IgG and IgY were first screened by ELISA. Then, positive samples were confirmed by plaque reduction neutralization test (PRNT). Besides this, adult mosquitoes were collected and tested for the presence of WNV RNA using conventional RT-PCR. Sera screening revealed a seroprevalence rate reaching 1.86% among humans and 2.47% among horses. Cross-reactions revealed by ELISA suggested the circulation of flaviviruses other than WNV. None of the tested mosquitoes was positive for WNV. The observed results constitute strong evidence of local exposure of the Lebanese population to this virus and the first report of equine WNV in Lebanon.
Topics: Antibodies, Neutralizing; Antibodies, Viral; Enzyme-Linked Immunosorbent Assay; Geography, Medical; Humans; Lebanon; Mass Screening; Neutralization Tests; Public Health Surveillance; Seroepidemiologic Studies; West Nile Fever; West Nile virus
PubMed: 34073485
DOI: 10.3390/v13060994 -
Viruses Jan 2023In 2022, Greece was the second most seriously affected European country in terms of the West Nile virus (WNV), after Italy. Specifically, Central Macedonia was the...
In 2022, Greece was the second most seriously affected European country in terms of the West Nile virus (WNV), after Italy. Specifically, Central Macedonia was the region with the most reported human cases (81.5%). In the present study, 30,816 female Culex pipiens sensu lato mosquitoes were collected from May to September 2022 in the seven regional units of Central Macedonia; they were then grouped into 690 pools and tested for WNV, while next-generation sequencing was applied to the samples, which showed a cycle threshold of Ct < 30 in a real-time RT-PCR test. WNV was detected in 5.9% of pools, with significant differences in the detection rate among regional units and months. It is of interest that in the Thessaloniki regional unit, where most of the human cases were observed, the virus circulation started earlier, peaked earlier, and lasted longer than in the other regional units. All sequences clustered into the Central European subclade of WNV lineage 2, and the virus strain differed from the initial Greek strain of 2010 by 0.52% and 0.27% at the nucleotide and amino acid levels, respectively. Signature substitutions were present, such as S73P and T157A in the prM and E structural proteins, respectively. The screening of mosquitoes provides useful information for virus circulation in a region with a potential for early warning, while the availability of whole-genome sequences is essential for further studies, including virus evolution.
Topics: Animals; Female; Humans; West Nile virus; Culex; Culicidae; Greece; West Nile Fever
PubMed: 36680264
DOI: 10.3390/v15010224 -
Virulence Dec 2021West Nile virus (WNV) is a flavivirus which transmission cycle is maintained between mosquitoes and birds, although it occasionally causes sporadic outbreaks in horses...
West Nile virus (WNV) is a flavivirus which transmission cycle is maintained between mosquitoes and birds, although it occasionally causes sporadic outbreaks in horses and humans that can result in serious diseases and even death. Since its first isolation in Africa in 1937, WNV had been considered a neglected pathogen until its recent spread throughout Europe and the colonization of America, regions where it continues to cause outbreaks with severe neurological consequences in humans and horses. Although our knowledge about the characteristics and consequences of the virus has increased enormously lately, many questions remain to be resolved. Here, we thoroughly update our knowledge of different aspects of the WNV life cycle: virology and molecular classification, host cell interactions, transmission dynamics, host range, epidemiology and surveillance, immune response, clinical presentations, pathogenesis, diagnosis, prophylaxis (antivirals and vaccines), and prevention, and we highlight those aspects that are still unknown and that undoubtedly require further investigation.
Topics: Animals; Culicidae; Europe; Horses; Virulence; West Nile Fever; West Nile virus
PubMed: 33843445
DOI: 10.1080/21505594.2021.1908740 -
Journal of the American Mosquito... Dec 2020Identifying the array of vectors that play a role in perpetuating West Nile virus (WNV) infection in endemic foci will help in controlling the disease. Aedes japonicus...
Identifying the array of vectors that play a role in perpetuating West Nile virus (WNV) infection in endemic foci will help in controlling the disease. Aedes japonicus has the potential to be a vector in the wild of at least 3 kinds of encephalitis, including WNV. Aedes japonicus is a nonnative species in the USA that is temperature tolerant and a potential human biter. Detection of WNV in mosquito pools of this field-collected invasive species, combined with their ability to feed on humans, make this mosquito species a possible public health concern. In this study, we collected mosquito abundance data and tested them for WNV-positive mosquito samples from 3 counties in New York State. We found a significant association between the season and land demography and the likelihood of the virus in Ae. japonicus.
Topics: Aedes; Animals; Female; New York; West Nile virus
PubMed: 33647113
DOI: 10.2987/20-6958.1 -
Viruses Jul 2022There are at least five common mosquito-borne viruses (MBVs) recorded in Egypt, including dengue virus (DENV), Rift Valley fever virus (RVFV), West Nile virus (WNV),... (Review)
Review
There are at least five common mosquito-borne viruses (MBVs) recorded in Egypt, including dengue virus (DENV), Rift Valley fever virus (RVFV), West Nile virus (WNV), Chikungunya virus, and Sindbis virus. Unexpected outbreaks caused by MBVs reflect the deficiencies of the MBV surveillance system in Egypt. This systematic review characterized the epidemiology of MBV prevalence in Egypt. Human, animal, and vector prevalence studies on MBVs in Egypt were retrieved from Web of Science, PubMed, and Bing Scholar, and 33 eligible studies were included for further analyses. The monophyletic characterization of the RVFV and WNV strains found in Egypt, which spans about half a century, suggests that both RVFV and WNV are widely transmitted in this nation. Moreover, the seropositive rates of DENV and WNV in hosts were on the rise in recent years, and spillover events of DENV and WNV to other countries from Egypt have been recorded. The common drawback for surveillance of MBVs in Egypt is the lack of seroprevalence studies on MBVs, especially in this century. It is necessary to evaluate endemic transmission risk, establish an early warning system for MBVs, and develop a sound joint system for medical care and public health for managing MBVs in Egypt.
Topics: Animals; Culicidae; Egypt; Humans; Rift Valley fever virus; Seroepidemiologic Studies; West Nile Fever; West Nile virus
PubMed: 35891557
DOI: 10.3390/v14071577 -
Emerging Infectious Diseases Apr 2022West Nile virus (WNV) is an emergent arthropodborne virus that is transmitted from bird to bird by mosquitoes. Spillover events occur when infected mosquitoes bite...
West Nile virus (WNV) is an emergent arthropodborne virus that is transmitted from bird to bird by mosquitoes. Spillover events occur when infected mosquitoes bite mammals. We created a geopositioned database of WNV presence in Africa and considered reports of the virus in all animal components: reservoirs, vectors, and nonhuman dead-end hosts. We built various biogeographic models to determine which drivers explain the distribution of WNV throughout Africa. Wetlands of international importance for birds accounted for the detection of WNV in all animal components, whereas human-related drivers played a key role in the epizootic cases. We combined these models to obtain an integrative and large-scale perspective of the areas at risk for WNV spillover. Understanding which areas pose the highest risk would enable us to address the management of this spreading disease and to comprehend the translocation of WNV outside Africa through avian migration routes.
Topics: Africa; Animals; Culicidae; Mammals; Mosquito Vectors; West Nile Fever; West Nile virus
PubMed: 35318911
DOI: 10.3201/eid2804.211103 -
Expert Opinion on Drug Discovery Mar 2020: West Nile virus (WNV) is a neurotropic mosquito-borne flavivirus, which is endemic in many countries, especially in Europe and in North America, where the virus has... (Review)
Review
: West Nile virus (WNV) is a neurotropic mosquito-borne flavivirus, which is endemic in many countries, especially in Europe and in North America, where the virus has increased its activity in the recent years. No vaccines nor antiviral drugs are available for the prevention and treatment of WNV infection in humans.: This review article describes viral and host targets that have been addressed by anti-WNV drug discovery studies and summarizes the most relevant anti-WNV candidate compounds identified so far, focusing on those showing antiviral efficacy in models and broad-spectrum anti-flavivirus activity.: The most promising anti-WNV drug candidates target conserved enzymatic motifs in viral NS3 protease and NS5 polymerase and are effective against different flaviviruses. Targeting host factors required for viral infection and replication and modulation of host innate antiviral response are also promising approaches, which may lead to the development of compounds with broad-spectrum antiviral activity, a desirable feature for an antiviral drug.
Topics: Animals; Antiviral Agents; Drug Development; Drug Discovery; Humans; Immunity, Innate; Mosquito Vectors; Virus Replication; West Nile Fever; West Nile virus
PubMed: 32017639
DOI: 10.1080/17460441.2020.1714586