High exposure of West Nile virus in equid and wild bird populations in Spain following the epidemic outbreak in 2020.
Abstract: A cross-sectional study was conducted to assess the circulation and risk factors associated with West Nile virus (WNV) exposure in equine and wild bird populations following the largest epidemic outbreak ever reported in Spain. A total of 305 equids and 171 wild birds were sampled between November 2020 and June 2021. IgG antibodies against flaviviruses were detected by blocking enzyme-linked immunosorbent assay (bELISA) in 44.9% (109/243) and 87.1% (54/62) of unvaccinated and vaccinated equids, respectively. The individual seroprevalence in unvaccinated individuals (calculated on animals seropositive by both bELISA and virus microneutralization test [VNT]) was 38.3% (95%CI: 33.1-43.4). No IgM antibodies were detected in animals tested (0/243; 0.0%; 95%CI: 0.0-1.5) by capture-ELISA. The main risk factors associated with WNV exposure in equids were age (adult and geriatric), breed (crossbred) and the absence of a disinsection programme on the facilities. In wild birds, IgG antibodies against flaviviruses were found in 32.7% (56/171; 95%CI: 26.8-38.6) using bELISA, giving an individual WNV seroprevalence of 19.3% (95%CI: 14.3-24.3) after VNT. Seropositivity was found in 37.8% of the 37 species analysed. Species group (raptors), age (>1-year old) and size (large) were the main risk factors related to WNV seropositivity in wild birds. Our results indicate high exposure and widespread distribution of WNV in equid and wild bird populations in Spain after the epidemic outbreak in 2020. The present study highlights the need to continue and improve active surveillance programmes for the detection of WNV in Spain, particularly in those areas at greatest risk of virus circulation.
© 2022 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.
Publication Date: 2022-10-22 PubMed ID: 36222172PubMed Central: PMC10092718DOI: 10.1111/tbed.14733Google Scholar: Lookup
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- Journal Article
Summary
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The research article focuses on a study tracing the high exposure and circulation of West Nile virus (WNV) among equine and wild bird populations in Spain, precipitated by a major epidemic outbreak in 2020. The study evaluates the predominant risk factors contributing to such exposure, underscoring the crucial role of constant, improved surveillance programs in virus detection and control.
Study Design and Sampling
- The research was built on a cross-sectional study aiming to measure the circulation of West Nile virus (WNV) and associated risk factors in equine and wild bird populations after the largest WNV outbreak in Spain.
- 305 equids (a family of mammals that include horses and zebras) and 171 wild birds were sampled between November 2020 and June 2021 to conduct this research.
Testing and Results
- A blocking enzyme-linked immunosorbent assay (bELISA) was used to identify IgG antibodies against flaviviruses—an important step in diagnosing the infection.
- In unvaccinated and vaccinated equids, the test results showed a high rate of flavivirus exposure, with 44.9% and 87.1% respectively being seropositive. No IgM antibodies were found, indicating a lack of recent exposure to the virus.
- In wild birds, 32.7% tested positive for flavivirus exposure using bELISA, revealing widespread WNV circulation among these populations as well.
Risk Factors
- For equids, identified risk factors for WNV exposure included age (adult and geriatric), breed (crossbred), and lack of a disinsection programme in their habitat facilities.
- For wild birds, risk factors included species (raptors), age (>1-year old), and size (large) in relation to WNV seropositivity.
Implications and Recommendations
- The study confirmed the high exposure and wide distribution of WNV in equid and wild bird populations following the 2020 epidemic.
- This underlines the importance of continuous and enhanced active surveillance, especially in areas of higher virus circulation risk, to better detect and manage WNV in Spain.
Cite This Article
APA
(2022).
High exposure of West Nile virus in equid and wild bird populations in Spain following the epidemic outbreak in 2020.
Transbound Emerg Dis, 69(6), 3624-3636.
https://doi.org/10.1111/tbed.14733 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Horses
- West Nile virus
- West Nile Fever / epidemiology
- West Nile Fever / veterinary
- Spain / epidemiology
- Seroepidemiologic Studies
- Cross-Sectional Studies
- Animals, Wild
- Flavivirus
- Birds
- Disease Outbreaks / veterinary
- Enzyme-Linked Immunosorbent Assay / veterinary
- Immunoglobulin G
- Antibodies, Viral
- Horse Diseases / epidemiology
Conflict of Interest Statement
None of the authors of this study has a financial or personal relationship with other people or organizations that could inappropriately influence or bias the content of the paper.
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