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Equine Encephalomyelitis Outbreak, Uruguay, 2023-2024

Sandra Frabasile et al. Emerg Infect Dis. 2025 Jan.

Abstract

We report the genomic analysis from early equine cases of the Western equine encephalitis virus outbreak during 2023-2024 in Uruguay. Sequences are related to a viral isolate from an outbreak in 1958 in Argentina. A viral origin from South America or continuous enzootic circulation with infrequent spillover is possible.

Keywords: Uruguay; Western equine encephalomyelitis; meningitis/encephalitis; outbreak; viruses; zoonoses.

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Figures

Figure 1
Figure 1
Location of samples analyzed in investigation of equine encephalomyelitis outbreak in Uruguay, 2023–2024. Red dots indicate equine Western equine encephalomyelitis virus cases in Uruguay. Green dots represent sequences retrieved from GenBank that correspond with equine Western equine encephalomyelitis virus cases from Rio Grande do Sul, Brazil. Blue dots represent human cases. Inset map shows location of Uruguay in South America.
Figure 2
Figure 2
Maximum-likelihood phylogenetic analysis of alphavirus sequences from South and North America and WEEV sequences described in investigation of equine encephalomyelitis outbreak, Uruguay. A) Phylogeny based on partial nonstructural protein 4 gene sequences. B) Phylogeny based on complete sequences. GenBank accession numbers are provided. Subclades are assigned as previously described (5,6). Clades including reference sequences from other alphaviruses were collapsed for better visualization. Red, sequences from Uruguay 2023–2024; orange, 2009 sequences; blue, sequences from Argentina; green, sequences from Brazil. Branch numbers are approximate likelihood ratio supports. Scale bar indicates substitutions per site. CHIKV, chikungunya virus; EEEV, Eastern equine encephalomyelitis virus; MADV, Madariaga virus; MDPV, Mosso das Pedras virus; MIDV, Middelburg virus; MAYV, Mayaro virus; MUCV, Mucambo virus; OCKV, Ockelbo virus; ONYV, o'nyong-nyong virus; RNV, Rio Negro virus; SINDV, Sindbis virus; VEEV, Venezuelan equine encephalitis virus; WEEV, Western equine encephalomyelitis virus.
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References

    1. Sánchez-Seco MP, Rosario D, Quiroz E, Guzmán G, Tenorio A. A generic nested-RT-PCR followed by sequencing for detection and identification of members of the alphavirus genus. J Virol Methods. 2001;95:153–61. 10.1016/S0166-0934(01)00306-8 - DOI - PubMed
    1. Moreira Marrero L, Botto Nuñez G, Frabasile S, Delfraro A. Alphavirus identification in neotropical bats. Viruses. 2022;14:269. 10.3390/v14020269 - DOI - PMC - PubMed
    1. Katoh K, Rozewicki J, Yamada KD. MAFFT online service: multiple sequence alignment, interactive sequence choice and visualization. Brief Bioinform. 2019;20:1160–6. 10.1093/bib/bbx108 - DOI - PMC - PubMed
    1. Guindon S, Dufayard JF, Lefort V, Anisimova M, Hordijk W, Gascuel O. New algorithms and methods to estimate maximum-likelihood phylogenies: assessing the performance of PhyML 3.0. Syst Biol. 2010;59:307–21. 10.1093/sysbio/syq010 - DOI - PubMed
    1. Bergren NA, Auguste AJ, Forrester NL, Negi SS, Braun WA, Weaver SC. Western equine encephalitis virus: evolutionary analysis of a declining alphavirus based on complete genome sequences. J Virol. 2014;88:9260–7. 10.1128/JVI.01463-14 - DOI - PMC - PubMed

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