Epidemiology and surveillance of West Nile virus in the Mediterranean Basin during 2010-2023: A systematic review.
Abstract: Climate change can cause spatio-temporal shifts in the epidemiology of various vector borne pathogens, especially in vulnerable areas such as the Mediterranean Basin (MB). Among these pathogens, the West Nile virus (WNV) became endemic in the region. This systematic review and meta-analysis study summarizes WNV epidemiology, molecular characteristics, and surveillance in various MB countries, relying on data and scientific articles on WNV published during 2010-2023. The number of published articles varied across the three MB subregions: Southern Europe (n = 153), North Africa (n = 33), and Western Asia (n = 14). During this period, 5765 WNV cases in humans were documented across 19 MB countries with peaks during 2018-2022, mostly in Italy and Greece. The latter had neurological disease in 70.3% of 1868 cases, and a high case fatality rate (13.7%). Fewer WNV cases were reported in North Africa despite having the highest pooled human seroprevalence (15.4%), suggesting potential underdiagnosis and cryptic transmission. Overall, 6.5% out of 160,775 individuals had WNV-IgG antibodies in their sera, and WNV-neutralizing antibodies (NA) were detected in ∼50% of 731 IgG-seropositive individuals, indicating co-circulation of other flaviviruses in the MB. In horses, 698 confirmed cases were reported across 14 MB countries. Compared to humans, horses had a higher pooled IgG (26.0%) and NA (71.8%) prevalence, but a lower case fatality rate (6.1%). Wild birds, the key amplifying hosts, displayed a pooled IgG seroprevalence of 11.9%. WNV-RNA was detected in 4.5% of 3040 dead or neurologically diseased wild birds. Entomological surveillance revealed WNV-RNA in 2.5% of 52,159 mosquito pools tested, mostly Culex pipiens. WNV lineages 1 and 2 co-circulate, with Lineage 2 being dominant in Southern Europe. Surveillance capabilities vary across subregions, with robust integrated strategies in Southern Europe and limited efforts in North Africa and Western Asia. Since no vaccines are available for humans, integrated One Health approaches are crucial for effective surveillance and early warning.
© 2025 The Authors.
Publication Date: 2025-06-02 PubMed ID: 40586111PubMed Central: PMC12205625DOI: 10.1016/j.crpvbd.2025.100277Google Scholar: Lookup
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The research article provides a detailed review and analysis of the epidemiology and surveillance of West Nile Virus (WNV) in the Mediterranean Basin region from 2010 to 2023, underlining the impacts of climate change on the spread of vector borne pathogens. The research underlines an increase in WNV cases in these regions during the said period, with a high impact on Italy and Greece, while highlighting potential underdiagnosis in North Africa. The prevalence of WNV in horses and wild birds is also discussed, and the research showcases the varying surveillance capabilities in different regions.
Epidemiology of West Nile Virus
- This study provides a synthesis of the epidemiology, molecular characteristics, and surveillance of West Nile virus (WNV) in various Mediterranean Basin (MB) countries based on data and articles published from 2010-2023.
- During this period, there were documented 5765 WNV cases in humans across 19 MB countries, with the most notable outbreaks in Italy and Greece, with high case fatality rates.
- The research highlights a significant prevalence of WNV, with 6.5% of tested individuals having WNV-IgG antibodies in their blood, and neutralizing antibodies were found in approximately 50% of IgG-seropositive individuals, suggesting co-circulation of other flaviviruses in the MB.
Underdiagnosis and Cryptic Transmission
- In North Africa, despite having the highest recorded human seroprevalence of 15.4%, fewer cases of WNV were reported, indicating possible underdiagnosis and covert transmission in the region.
Prevalence in Horses and Wild Birds
- The research reveals that the infection rate was higher in horses, with a reported 698 cases across 14 MB countries during the reviewed time. Compared to humans, horses displayed a higher prevalence of IgG (26.0%) and neutralizing antibodies (71.8%) but a lower fatality rate (6.1%).
- Wild birds, the key hosts for WNV amplification, showed an IgG seroprevalence of 11.9%, while 4.5% of tested dead or neurologically impaired birds had WNV-RNA detected.
Surveillance and Control Measures
- Surveillance capacities were revealed to vastly differ across the various subregions, with Southern Europe displaying more robust and integrated strategies as compared to North Africa and Western Asia.
- Due to the absence of a vaccine for humans, the study underlines the importance of a One Health approach that integrates human, animal, and environmental health for effective surveillance and early warning.
Cite This Article
APA
Abbas I, Ahmed F, Muqaddas H, Alberti A, Varcasia A, Sedda L.
(2025).
Epidemiology and surveillance of West Nile virus in the Mediterranean Basin during 2010-2023: A systematic review.
Curr Res Parasitol Vector Borne Dis, 7, 100277.
https://doi.org/10.1016/j.crpvbd.2025.100277 Publication
Researcher Affiliations
- Parasitology Department, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt.
- Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Coleraine, BT52 1SA, UK.
- Department of Zoology, The Women University Multan, Multan, Pakistan.
- Department of Veterinary Medicine, University of Sassari, Sassari, Italy.
- Department of Veterinary Medicine, University of Sassari, Sassari, Italy.
- Lancaster Ecology and Epidemiology Group, Lancaster University, UK.
Conflict of Interest Statement
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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