Molecular Epidemiology of Western Equine Encephalitis Virus, South America, 2023-2024.
Abstract: Western equine encephalitis virus (WEEV) is a mosquitoborne virus that reemerged in December 2023 in Argentina and Uruguay, causing a major outbreak. We investigated the outbreak using epidemiologic, entomological, and genomic analyses, focusing on WEEV circulation near the Argentina‒Uruguay border in Rio Grande do Sul state, Brazil. During November 2023‒April 2024, the outbreak in Argentina and Uruguay resulted in 217 human cases, 12 of which were fatal, and 2,548 equine cases. We determined cases on the basis of laboratory and clinical epidemiologic criteria. We characterized 3 fatal equine cases caused by a novel WEEV lineage identified through a nearly complete coding sequence analysis, which we propose as lineage C. Our findings highlight the importance of continued surveillance and equine vaccination to control future WEEV outbreaks in South America.
Publication Date: 2024-08-23 PubMed ID: 39173662PubMed Central: PMC11346983DOI: 10.3201/eid3009.240530Google Scholar: Lookup
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- Journal Article
Summary
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The research article discusses a major outbreak of the Western equine encephalitis virus (WEEV) that occurred in Argentina and Uruguay from November 2023 to April 2024 and proposes a new lineage or variant of the virus based on the genomic analysis of fatal equine cases.
Study Design and Focus
- This study is an in-depth investigation into a major outbreak of the Western equine encephalitis virus (WEEV) that occurred in Argentina and Uruguay.
- The research focused specifically on WEEV circulation near the Argentina–Uruguay border in the state of Rio Grande do Sul in Brazil.
- It applied a combination of epidemiologic, entomological, and genomic analyses to gather data and insights.
Outbreak Impact
- This major outbreak of WEEV spanned a period from November 2023 to April 2024.
- In total, the outbreak resulted in 217 human cases, with 12 of those being fatal.
- Additionally, there were 2,548 equine cases reported during the same period.
Methodology and Findings
- Case determination was based on laboratory and clinical epidemiologic criteria, ensuring a rigorous and evidence-based approach.
- Three fatal equine cases were extensively analyzed revealing a newly identified lineage of the WEEV.
- This new variant was discovered through meticulous coding sequence analysis and has been proposed to be called “lineage C”.
Importance and Implications
- The study underscores the significance of regular surveillance and equine vaccination in controlling future outbreaks of WEEV in South America.
- This newly identified lineage “C” gives important insights into the evolving nature of the WEEV virus, which could be essential in developing effective preventive and control strategies.
Cite This Article
APA
Campos AS, Franco AC, Godinho FM, Huff R, Candido DS, da Cruz Cardoso J, Hua X, Claro IM, Morais P, Franceschina C, de Lima Bermann T, Dos Santos FM, Bauermann M, Selayaran TM, Ruivo AP, Santin C, Bonella J, Rodenbusch C, Ferreira JC, Weaver SC, Gewehr VR, Wallau GL, de Souza WM, Salvato RS.
(2024).
Molecular Epidemiology of Western Equine Encephalitis Virus, South America, 2023-2024.
Emerg Infect Dis, 30(9), 1834-1840.
https://doi.org/10.3201/eid3009.240530 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Encephalitis Virus, Western Equine / genetics
- Humans
- Disease Outbreaks
- Horses
- Phylogeny
- Molecular Epidemiology
- Uruguay / epidemiology
- South America / epidemiology
- Horse Diseases / epidemiology
- Horse Diseases / virology
- Male
- Encephalomyelitis, Western Equine / epidemiology
- Encephalomyelitis, Western Equine / virology
- Female
- Argentina / epidemiology
- Encephalomyelitis, Equine / epidemiology
- Encephalomyelitis, Equine / virology
- Encephalomyelitis, Equine / veterinary
- Adult
Grant Funding
- Wellcome Trust
- R01 AI121452 / NIAID NIH HHS
- U01 AI151801 / NIAID NIH HHS
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