A-Z Index × Submit A-Z Index × Submit A-Z Index Search Dropdown × Submit Facebook Twitter LinkedIn Syndicate Emerging Infectious Disease journal ISSN: 1080-6059 Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
We describe 5 cases of human Oropouche virus infection detected in rural Venezuela in 2025. All isolates belonged to the OROVBr 2015–2024 reassortant lineage linked to the 2024–2025 epidemic. Our results emphasize ongoing transmission, which highlights the need for strengthened surveillance and laboratory capacity in South America.
Oropouche virus (OROV) is an arthropodborne virus and member of the family Peribunyaviridae, genus Orthobunyavirus ; the species is Orthobunyavirus oropoucheense . The genome consists of 3 segments of a linear negative-stranded RNA: small, medium, and large ( 1 ). Several outbreaks of OROV infection have occurred in the Amazon region since 1960. The largest OROV outbreak has been ongoing since 2022 ( 1 ). By February 2025, a total of 9 countries in the Americas reported autochthonous cases of OROV. Meanwhile Canada, Cayman Islands, the United States, Germany, Italy and Spain also reported 30 imported cases, mostly in travelers returning from Cuba ( 2 ).
Figure 1 . Locations of Oropouche virus cases detected in Venezuela, 2025. The numbers represent the cases detected. The cases were detected in the Portugesa and Miranda states. The first detected Oropouche virus...
The National Institute of Hygiene Rafael Rangel (Caracas, Venezuela) has been detecting OROV by using reverse transcription PCR since 2023. Beginning in 2024, a total of 25% of the samples negative for dengue, chikungunya, and Zika viruses were tested for Mayaro and Oropuche viruses by quantitative reverse transcription PCR (qRT-PCR) ( 3 ). During the first trimester of 2025, five samples tested positive for OROV by qRT-PCR in 2 states of Venezuela, Miranda and Portuguesa ( Figure 1 ). After the first case of OROV was detected in January 2025, all the samples negative for the 3 other arboviruses from January–March 2025 were retrospectively tested for Mayaro virus and OROV, which were all negative. This study was approved by the Bioethical Committee of Instituto Venezolano de Investigaciones Científicas (protocol no. CBioEtIVIC-2022–001): written informed consent was obtained in OROV-positive human cases. We described the clinical findings of the 5 patients in accordance with the Pan American Health Organization guidelines ( Appendix Table 1) ( 2 ). We observed no neurologic compromise in those cases. For the first case, the patient had a possible relapse 3 weeks later, although qRT-PCR was negative. Recurrence seems to be a frequent phenomenon in OROV infection ( 4 ).
We collected serum samples 2 or 3 days after the appearance of acute febrile illness. We performed genome sequencing on an Illumina iSeq platform (Illumina, https://www.illumina.com ) by using a COVIDSeq library and primers specific for the OROV genome ( Appendix Table 2) ( 2 ). We assembled genome sequences by using both Genome Detective ( https://www.genomedetective.com ) and INSaFLU-TELEVIR bioinformatic tools ( https://insaflu.insa.pt ).
We deposited complete genome sequences into the GISAID database (accession nos. EPI_ISL_19859479–81), and in GenBank (GenBank accession nos. PX494099–101, PX495048–50 and PX495206–8). We aligned sequences by usin…