Chikungunya Virus Replication Rate Determines the Capacity of Crossing Tissue Barriers in Mosquitoes

Abstract

It is well established that selective pressures in mosquito vectors impose population bottlenecks for arboviruses. Here, we used a CHIKV Caribbean lineage mutant carrying a deletion in the 3′ UTR to study host-virus interactions in vivo in the epidemic mosquito vector Aedes aegypti . We found that the mutant virus had a delayed replication rate in mosquitoes, which lengthened the extrinsic incubation period (EIP) and reduced fitness relative to the wild-type virus. As a result, the mutant virus displayed a reduced capacity to cross anatomical barriers during the infection cycle in mosquitoes, thus reducing the virus transmission rate. Our findings show how selective pressures act on CHIKV noncoding regions to select variants with shorter EIPs that are preferentially transmitted by the mosquito vector.