The global outbreak of Oropouche virus: surveillance of global trends

Oropouche virus (OROV) is a re-emerging arthropod-borne virus of the genus Orthobunyavirus (family Peribunyaviridae) that poses an increasing public health concern in South and Central America and the Caribbean. First identified in Trinidad in 1955, OROV has caused recurrent outbreaks, with recent resurgence associated with geographic expansion and increased urban transmission. In 2024 alone, more than 11,600 confirmed cases were reported in the Region of the Americas, with continued transmission documented in early 2025. The virus is primarily transmitted in urban settings by the biting midge Culicoides paraensis, while other mosquito species have demonstrated variable laboratory vector competence. Clinically, OROV infection presents as an acute febrile illness resembling dengue, chikungunya, and other arboviral infections, frequently complicating diagnosis in co-endemic areas. Although molecular diagnostics such as RT-PCR enable early detection, standardized diagnostic protocols and validated commercial assays remain limited. No specific antiviral therapy or licensed vaccine is currently available, and prevention relies on vector control and personal protective measures. Emerging evidence has raised concern regarding potential vertical transmission of OROV during pregnancy. Case reports and recent genomic analyses have described associations between maternal infection and adverse fetal outcomes, including stillbirth, congenital microcephaly, and structural anomalies. Detection of viral RNA in placental or fetal tissues supports biological plausibility; however, systematic cohort-based epidemiological data remain limited. At present, causality cannot be definitively established, and further prospective surveillance studies are urgently needed to clarify risk magnitude and pathogenic mechanisms. This review synthesizes current knowledge on the epidemiology, virology, transmission dynamics, clinical manifestations, diagnostics, and prevention strategies of OROV and identifies key research priorities to strengthen surveillance, preparedness, and outbreak response in affected and at-risk regions.