High capacity of BrazilianAedes aegyptipopulations to transmit a locally circulating lineage of Chikungunya virus

Abstract

AbstractThe global incidence of chikungunya has surged in recent decades, with South America, particularly Brazil, experiencing devastating outbreaks. The primary vector for transmitting CHIKV in urban areas is the mosquito speciesAedes aegypti, which is very abundant in Brazil. However, little is known about the impact of locally circulating CHIKV genotypes and specific combinations of mosquito populations on vector competence. In this study, we analyzed and compared the infectivity and transmissibility of a recently isolated CHIKV-ECSA lineage from Brazil among fourAe. aegyptipopulations collected from different regions of the country. When exposed to CHIKV-infected mice for blood feeding, all mosquito populations showed high infection rates and dissemination efficiency. Moreover, using a mouse model to assess transmission rates in a manner that better mirrors natural cycles, we observed that these populations exhibit highly efficient transmission rates of CHIKV-ECSA. Our findings underscore the robust capability of BrazilianAe. aegyptipopulations to transmit the locally circulating CHIKV-ECSA lineage, potentially explaining its higher prevalence compared to the Asian lineage also introduced in Brazil.Author SummaryChikungunya virus (CHIKV) is an alphavirus transmitted by mosquitoes, gaining attention due to its rapid global spread and public health impact. Initially isolated in Tanzania in 1952, it was confined to Africa, Asia, and the Indian subcontinent. Local transmission of CHIKV in the Americas began in December 2013, leading to a 2014 epidemic. TheAedes aegyptimosquito, prevalent in Brazil, is suspected as the primary vector. Yet, our understanding of how different mosquito populations and virus lineages impact spread is limited. In this Brazilian study, we collected mosquitoes from four regions, exposing them to the local African ECSA lineage of CHIKV. Remarkably, all mosquito populations exhibited high infection rates and efficient virus transmission to vertebrate hosts. This research sheds light on why the ECSA chikungunya lineage is spreading rapidly in Brazil. The BrazilianAe. aegyptimosquitoes appear to possess exceptional capabilities in transmitting African ECSA lineage of CHIKV, potentially contributing to its rapid dissemination within the country and neighboring regions. Comprehending these dynamics is vital for developing strategies to control and mitigate the impact of chikungunya in affected areas.