Oropouche virus disease

Oropouche virus disease is a febrile zoonotic illness caused by Oropouche virus, a segmented single-stranded RNA arbovirus in the genus Orthobunyavirus, family Peribunyaviridae, first isolated in 1955 from a febrile patient in Vega de Oropouche, Trinidad and Tobago ^[1][2][5].

After an incubation period of typically 3 to 10 days following the bite of an infected arthropod, illness begins abruptly with fever, headache, arthralgia, myalgia, chills, nausea, vomiting, and rash, with most patients recovering within about 7 days though some experience prolonged illness or a biphasic course with recurrence about a week after onset ^[2][3]. Severe manifestations are uncommon but may include aseptic meningitis, encephalitis, peri-infectious Guillain-Barré syndrome, and—reported for the first time in 2024—two deaths in previously healthy young adults ^[2][3]. Possible vertical transmission with associated fetal adverse outcomes including stillbirth, miscarriage, and microcephaly has been described, although causality for fetal loss has not been definitively established ^[2][3].

OROV is endemic to parts of South America, Central America, and the Caribbean, with most historically reported cases occurring near the Amazon rainforest in countries including Brazil, Peru, Panama, Bolivia, Colombia, Ecuador, Haiti, French Guiana, Trinidad and Tobago, and Venezuela ^[1][2][5]. Brazil has recorded more than 30 epidemics and over half a million cumulative clinical cases, making OROV fever the second most common arboviral disease in Brazil after dengue and, before chikungunya and Zika emerged in 2013 and 2015, the second most common arboviral disease in South America overall ^[1][2]. Since late 2023, transmission has been documented in previously non-endemic regions; in 2024, locally acquired cases were reported across seven Latin American and Caribbean countries, including for the first time in Cuba, with 9,852 confirmed cases reported by the end of August 2024 ^[3][4].

OROV is maintained in two distinct cycles: a sylvatic cycle involving forest-dwelling hosts such as sloths, non-human primates, and birds together with mosquitoes, and an urban cycle in which the anthropophilic biting midge Culicoides paraensis serves as the primary vector and humans act as the amplifying host ^[1][3][5]. Human infection occurs through the bite of an infected midge or, less commonly, mosquito, and no direct human-to-human transmission has been documented to date ^[1][2][5]. Recent evidence of vertical transmission from mother to fetus during pregnancy raises additional transmission routes warranting further investigation ^[2][3].

Recommended individual strategies include the use of insect repellents, wearing protective clothing, and sleeping under fine-mesh bed nets, complemented by community-level vector management targeting Culicoides midges and mosquitoes in both urban and sylvatic transmission settings ^[1][5].

1. 1Sakkas H et al. Oropouche Fever: A Review. Viruses. 2018 Apr 4. PMID: 29617280. doi: 10.3390/v10040175.PubMed: https://pubmed.ncbi.nlm.nih.gov/29617280/
2. 2World Health Organization. Oropouche virus disease [Internet]. cited 4 Sept 2026.Available from: https://www.who.int/news-room/fact-sheets/detail/oropouche-virus-disease
3. 3Pastula DM et al. Oropouche Virus: An Emerging Neuroinvasive Arbovirus. Ann Neurol. 2024 Nov 19. PMID: 39560215. doi: 10.1002/ana.27139.PubMed: https://pubmed.ncbi.nlm.nih.gov/39560215/
4. 4Tilston-Lunel NL et al. Oropouche Virus: An Emerging Orthobunyavirus. J Gen Virol. 2024 Oct. PMID: 39351896. doi: 10.1099/jgv.0.002027.PubMed: https://pubmed.ncbi.nlm.nih.gov/39351896/
5. 5Zhang Y et al. Oropouche virus: A neglected global arboviral threat. Virus Res. 2024 Mar. PMID: 38224842. doi: 10.1016/j.virusres.2024.199318.PubMed: https://pubmed.ncbi.nlm.nih.gov/38224842/