Natural Infection of Aedes aegypti by Chikungunya and Dengue type 2 Virus in a Transition Area of North-Northeast Brazil

Abstract

Dengue fever, chikungunya, and Zika are diseases caused by viruses transmitted by <i>Aedes aegypti</i> and <i>Aedes albopictus</i>. In Brazil, the number of human infections is high, but few studies are performed in mosquito vectors. This study aimed to investigate the presence of Zika, Dengue and Chikungunya viruses in <i>Ae. aegypti</i> and <i>Ae. albopictus</i> from the municipalities of Alto Alegre, Caxias, Codó, and São Mateus do Maranhão, located in the state of Maranhão, Northeast Brazil. The mosquitoes were collected with a mechanical aspirator, identified, triturated, and then submitted to RNA extraction and RT-qPCR. The positive samples were confirmed by virus isolation and genome sequencing. Three hundred and forty-eight <i>Ae. aegypti</i> (176 males and 172 females) and 12 <i>Ae. albopictus</i> (eight males and four females) were collected and tested. <i>Ae. aegypti</i> was the only vector positive in two municipalities-Codó, with detection of <i>Chikungunya virus</i> (CHIKV) belonging to the East-Central-South African genotype, and in Caxias, with detection of <i>Dengue virus</i> (DENV)-2 belonging to the Asian/American genotype. The detection of CHIKV and DENV-2 is evidence that those viruses are maintained in arthropod vectors, and shows the epidemiological risk in the area for chikungunya cases and a possible increase of severe dengue cases, associated with the occurrence of dengue hemorrhagic fever.