Emergence of genotype III St. Louis encephalitis virus in the western United States potentially linked to a wetland in Argentina

BERANEK M.; TORRES C.; LAURITO, MAGDALENA; FARIAS, A.; CONTIGIANI, M.; ALMIRÓN, WALTER R; DIAZ A.

Acta Tropica

Elsevier B.V.

Año: 2024 vol. 250

St. Louis encephalitis virus (SLEV) is endemic in the Americas and its transmission networks involve Culex mosquitoes and avian species. In 2015, a human encephalitis outbreak took place in Arizona and California, indicating the re-emergence of this pathogen in the US. Viral strains isolated in that outbreak belong to genotype III SLEV previously detected only in South America. In this study, genotype III SLEV was detected in mosquitoes collected in Mar Chiquita Lagoon (C´ ordoba, Argentina), an overwintering site for numerous migratory bird species. The genotype III SLEV sequence detected in this site shares the closest known ancestor with those introduced in Arizona in 2015. Our results highlight the potential significance of wetlands as key sites for arbovirus maintenance and emergence.