First Chikungunya-infected Aedes aegypti mosquitoes found in Brazil

Chikungunya, which often causes a fever and joint pain, is endemic in Africa and Asia and was first reported to be transmitted within Brazil in 2014. Researchers have identified three genotypes of Chikungunya virus (CHIKV) -- ECSA, West African, and Asian. Both ECSA and Asian genotypes of CHIKV have been reported in patients in Brazil, and all Brazilian states are infested with Aedes aegypti and Ae. albopictus mosquitoes, which have both been shown to be possible vectors of CHIKV in the lab.

In the new work, Margareth Capurro, of the University of Sao Paulo, Brazil, and colleagues collected 248 mosquitoes from both inside and outside homes in urban areas of Aracaju, where residents were complaining of symptoms consistent with CHIKV or related diseases. They then tested the mosquitoes for CHIKV, as well as dengue virus and Zika virus.

Four strains of mosquitoes were captured, with Culex quinquefasciatus the most common, making up 78.2%, and Ae. aegypti making up 20.2% of the mosquitoes. One female Aedes aegypti mosquito was identified as carrying CHIKV and when the genome was sequenced, it was found to be the ECSA genotype. No mosquitoes carrying dengue or Zika were identified in the current study.

"The surveillance of the Aedes mosquito should be expanded in order to prevent new CHIKV outbreaks in Brazil, since this country presents adequate conditions for the establishment of an endemic situation, which can also expose other countries at risk," the authors write.