Comprehensive analysis of epidemiological and clinical features of Oropouche virus infection (1975 to 2025): a systematic review

Background Oropouche virus (OROV) has re-emerged since late 2023 with expanding urban transmission in Latin America. OROV causes an acute febrile illness with symptoms overlapping other arboviral infections, complicating diagnosis. Recent reports of fatalities and suspected vertical transmission have raised concerns regarding disease severity. This study aims to provide a comprehensive analysis of epidemiological and clinical features of OROV infection.

Methods We conducted a PRISMA-compliant systematic review by searching major bibliographic databases and preprint servers. Observational studies reporting OROV infection in febrile patients or the general population were included, and pooled prevalence estimates were calculated.

Results 59 studies were included. The pooled seroprevalence of anti-OROV antibodies in the general population was 7% (95% CI, 0-21%). Among febrile patients, pooled prevalence was 16% (95% CI, 10-24%) by virus detection and 24% (95% CI, 13-36%) by serology. Sex distribution was comparable (male 51% vs female 49%), while infections were most common among individuals aged 20-39 years (38%; 95% CI, 32-43%). The most frequent symptoms were fever (94%; 95% CI, 90-98%), headache (87%; 95% CI, 84-91%), and myalgia (73%; 95% CI, 67-80%), with gastrointestinal and ocular manifestations also common. Compilation of reported fatal cases showed a rapidly progressive clinical course. 17 pregnancy-associated cases suggested possible vertical transmission with heterogeneous outcomes, including congenital abnormalities and fetal loss.

Conclusions OROV contributes to acute febrile illness in Latin America and presents as a multisystem disease. Emerging reports of fatal outcomes and pregnancy-associated adverse events warrant heightened clinical awareness, improved diagnostics, and strengthened surveillance.