Oropouche fever (OROV) is a neglected arboviral disease transmitted by Culicoides paraensis, with sylvatic and urban cycles. Although initially considered benign, outbreaks recorded in Brazil in 2023 and 2024 revealed an increase in cases and clinical severity, including deaths and neurological complications, highlighting its epidemic potential and risk to public health. The objective of this article was to address the impacts and the main clinical characteristics of Oropouche fever, a little-known and under-studied viral disease that is often confused with other arboviral diseases. This is a systematic review with meta-analysis, based on the PICOS strategy, registered in PROSPERO (ID: CDRD420251083644). The guiding question was: “What was the impact of the Oropouche fever outbreak in Brazil in 2024 and what are its main clinical and epidemiological characteristics?”. The search was conducted in PubMed, BVS, and LILACS, including articles published between 2024 and 2025, in Portuguese, English, and Spanish. Studies with clinical, epidemiological, and social data on the 2024 outbreak in Brazil were included. After screening and eligibility criteria, 10 original articles were selected. A total of 13,801 confirmed cases were identified in 2024, with expansion to non-endemic states. Studies pointed to a new viral lineage with greater virulence and immune escape capacity. Severe cases included meningitis, encephalitis, and vertical transmission, resulting in congenital malformations such as microcephaly. The increase in cases was related to environmental factors such as deforestation, climate change, and precarious urbanization. The lack of specific diagnosis and similarities with dengue and zika favored underreporting. Evidence of autochthonous transmission in urban areas and new strains with rapid replication suggest a high potential for dissemination. The North region was the most affected, and the 20–49-year age group concentrated most cases. Oropouche fever is an emerging and neglected threat. Recent outbreaks demonstrate its clinical severity and the need for active surveillance, specific diagnosis, prevention campaigns, and investment in vaccines. Recognizing the risk is essential to prevent new outbreaks and protect vulnerable populations.
Mazuco et al. (Sun,) studied this question.