Between the unknown and the emerging: mapping the Oropouche and Mayaro viruses in Brazil

Abstract

Arboviruses are infectious diseases caused by arthropod-transmitted viruses. Before the introduction of the Chikungunya and Zika viruses in Brazil, the Oropouche virus (OROV) was the second most prevalent arbovirus in humans, behind only Dengue. Currently, the Mayaro virus (MAYV) and OROV stand out as important viral agents, especially in the Amazon Region. Despite the considerable impact, cases of OROV and MAYV remain neglected and underreported. The aim of the present study was to analyze the geospatial distribution of cases of OROV and MAYV to assist in the implementation of control measures. For such, a cross-sectional study was conducted using secondary data obtained via Fala.BR from the Laboratory Environment Manager and the Brazilian Institute of Geography and Statistics on Mayaro fever and Oropouche fever, including laboratory records and population-based information for epidemiological and spatial analysis. A total of 16,571 cases of OROV and 379 cases of MAYV were analyzed. The spatial analysis revealed clusters of the high incidence (high-high) of OROV in the North Region and the state of Espírito Santo. High-high clusters of MAYV were found in the North Region and points in the Central-West. The overlap between deforestation in the Amazon and the incidence of cases suggests a spatial relationship. The areas with the highest incidence coincide with intensely deforested regions. The increase in cases of MAYV and OROV may be linked to the decentralization of the diagnosis and active search in negative samples. The cases are concentrated in the North, where environmental and social factors favor transmission, especially in vulnerable populations. There is evidence of a relationship between incidence and deforestation. MAYV also has an apparent association with environmental degradation.