Geographic Expansion of Oropouche Fever Into Non-Endemic Regions of Brazil: Implications for Health Surveillance

Oropouche fever is an arboviral disease caused by the Oropouche virus (OROV; Peribunyaviridae family), first identified in Brazil in 1960. This study aims to describe the epidemiological profile and spatio-temporal dispersion of Oropouche fever cases across Brazil in 2024. The variables analyzed were sex, age, transmission area, macroregion, and federative unit. A simple descriptive analysis (absolute frequencies and proportions) was performed. Data were extracted from the Oropouche Fever Epidemiological Panel and the Brazilian Institute of Geography and Statistics (IBGE). The analysis revealed 13,786 reported cases (6.80/100,000 inhabitants), with a predominance of males (52.6%; n = 7247). The North region presented the highest incidence (41.60%; n = 5732; 33.03/100,000 inhabitants). Incidence peaks during early (weeks 5-6) and late 2024 (week 52) were identified, with heterogeneous regional spread reflecting a possible outbreak progression from the North to Northeast and subsequently Southeast. Espírito Santo state recorded the highest national incidence (151.60/100,000 inhabitants; 42.20% of cases; n = 5812). The expansion of OROV into non-endemic regions highlights an emerging public health threat. Urgent, systematic measures are required to strengthen Brazil's health surveillance system, ensuring timely and effective responses to mitigate further geographic spread.