Fatal Oropouche Virus Infections in Nonendemic Region, Brazil, 2024

Abstract

We report acute Oropouche virus infections in 2 previously healthy women from a nonendemic region of Brazil outside the Amazon Basin. Infections rapidly progressed to hemorrhagic manifestations and fatal outcomes in 4-5 days. These cases highlight the critical need for enhanced surveillance to clarify epidemiology of this neglected disease.

Keywords: Bahia; Brazil; Oropouche fever; Oropouche virus; outbreak; vector-borne infections; viruses.

Figure

Maximum-likelihood phylogenetic trees of the 3 independent OROV segments from fatal Oropouche virus infections in nonendemic region, Brazil, 2024. A) Medium segment (n = 122); B) large segment (n = 138); C) small segment (n = 264). Tips of prototypical viruses and major clusters are color-coded according to locations of isolation. The trees included annotations indicating the bootstrap probability support for both major lineages and specific clades. Trees were constructed by using IQ-TREE 2 software under the Hasegawa-Kishino-Yano plus gamma 4 substitution model (11). MDDV was included as an outgroup in the large and small segment trees. Scale bars indicate nucleotide substitutions per site. MDDV, Madre de Dios virus; OROV, Oropouche virus.