Arbovirus outbreak in a rural region of the Brazilian Amazon.

Background: An outbreak of febrile illness was reported from January to February 2018 in the Expedito Ribeiro Settlement, ​​Santa Bárbara do Pará municipality, Pará State, Brazil.

Objective: This study aimed to investigate the pathogenic agent responsible for the outbreak and the circulation of arboviruses in the region.

Study Design: We analyzed 94 individuals through laboratory tests for arboviruses. Forty out of 94 individuals were asymptomatic but were living with or near febrile cases, and 55 participants were symptomatic.

Results: Our results showed that 51.1% of the investigated individuals were positive for arboviruses (Oropouche, Mayaro, and Chikungunya), of which 77.8% were symptomatic. We detected 93.7% of positive cases for Oropouche infection, 2.1% for Mayaro fever, and 4.2% were positive for both Oropouche and Chikungunya infection.

Conclusion: Oropouche virus was mainly responsible for the outbreak; however, we also detected a few Chikungunya and Mayaro fever cases. Serologic assays showed evidence of arboviruses circulation of different genera in the area.