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Volume 32, Number 8—August 2026

CME ACTIVITY - Synopsis

Western Equine Encephalitis Virus in Blood Donors during Outbreak, Argentina, 2023–2024

Sebastián BlancoComments to Author , María C. Frutos, Kevin Brenot, Alejandra González Bustamante, Luis H. Carrizo, and Sandra V. Gallego
Author affiliation: Universidad Católica de Córdoba, Córdoba, Argentina (S. Blanco); Universidad Nacional de Córdoba, Córdoba (S. Blanco, M.C. Frutos, K. Brenot, S.V. Gallego); Fundación Banco Central de Sangre, Córdoba (S. Blanco, A. González Bustamante, L.H. Carrizo, S.V. Gallego); Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina (M.C. Frutos, S.V. Gallego)

Main Article

Figure

Phylogenetic analysis from study of western equine encephalitis virus (WEEV) in blood donors during outbreak, Argentina, 2023–2024. We generated a maximum-likelihood phylogenetic tree of a partial nucleotide sequence nonstructural protein 4 (201 bp) of a WEEV isolate from Argentina (black square) compared with other sequences from GenBank (accession numbers shown). We edited the tree using FigTree version 1.4.4 (https://tree.bio.ed.ac.uk/software/figtree). We selected the best-fit nucleotide substitution model general time-reversible substitution model with estimated base frequencies and gamma-distribution rate with 4 discrete categories according to the Bayesian Information Criterion. Black dots at nodes show the highest support (>80%) by SH-like approximate-likelihood ratio test. WEEV strains from the 2023–2024 outbreak group closely with other reported strains from Uruguay and Brazil (C sublineage). We defined WEEV lineages in accordance with previous research (22). Scale bar indicates number of nucleotide substitutions per site.

Figure. Phylogenetic analysis from study of western equine encephalitis virus (WEEV) in blood donors during outbreak, Argentina, 2023–2024. We generated a maximum-likelihood phylogenetic tree of a partial nucleotide sequence nonstructural protein 4 (201 bp) of a WEEV isolate from Argentina (black square) compared with other sequences from GenBank (accession numbers shown). We edited the tree using FigTree version 1.4.4 (https://tree.bio.ed.ac.uk/software/figtree). We selected the best-fit nucleotide substitution model general time-reversible substitution model with estimated base frequencies and gamma-distribution rate with 4 discrete categories according to the Bayesian Information Criterion. Black dots at nodes show the highest support (>80%) by SH-like approximate-likelihood ratio test. WEEV strains from the 2023–2024 outbreak group closely with other reported strains from Uruguay and Brazil (C sublineage). We defined WEEV lineages in accordance with previous research (22). Scale bar indicates number of nucleotide substitutions per site.

Main Article

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Page created: June 07, 2026
Page updated: July 22, 2026
Page reviewed: July 22, 2026
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