Clinical and Epidemiological Characteristics of an Oropouche Virus Outbreak in Loreto, Peru (October 2024–March 2025)

Oropouche virus (OROV) has emerged as a significant arboviral pathogen in South America, responsible for recurrent outbreaks of febrile illness. In the Loreto region of Peru, more than 600 cases were reported in 2024, markedly exceeding expected incidence rates. We conducted a retrospective observational study using clinical-epidemiological records of all RT-qPCR-confirmed cases of Oropouche fever from the Regional Health Directorate of Loreto between October 2024 and March 2025. A total of 100 confirmed cases were identified. The most frequent symptoms were fever (88%), headache (78%), and myalgia (72%). No atypical or neurological presentations were reported. No severe cases or deaths occurred. Eight patients required hospitalization, mainly due to severe abdominal pain, persistent vomiting, arthralgia, and pregnancy. Six pregnant women were identified; three experienced pregnancy complications, though no fetal malformations or miscarriages were observed. This outbreak represents a new OROV epidemic in the region, with fewer cases than in 2024 and predominantly mild clinical courses. Although outcomes were generally favorable, the occurrence of complications in pregnant women underscores the importance of continued molecular surveillance and targeted public health interventions.