Distinct New York Cityaedes Albopictusmosquito Populations Display Differences In Salivary Gland Protein D7 Diversity And Chikungunya Virus Replication

In an increasingly interconnected world, the exposure and subsequent spread of emergent viruses has become inevitable. This is particularly true forAedes(Ae.) mosquito-vectored viruses, whose range has increased over the past decade from tropical to temperate regions. However, it is unclear if all populations ofAe.mosquitoes in temperate New York City are able to successfully replicate and transmit arboviruses. To answer this question, we rearedAe. albopictusmosquitoes living in a temperate climate from three locations in New York City. We first sequenced the salivary antiviral protein D7 from individual mosquitoes in each population and found single nucleotide variants that are both shared and unique for eachAe. albopictuspopulation. We then fed each population chikungunya virus (CHIKV) via an artificial blood meal. All three mosquito populations could be infected with CHIKV, yet viral titers differed between populations at 7 days post infection. Moreover, we found that these mosquitoes could transmit CHIKV to mice, and that virus RNA reached the saliva as early as two days post infection. Upon sequencing of the saliva CHIKV genomic RNA, we found mutations at sites correlated with increased transmission and virulence. These studies show that NYCAe. albopictuspopulations can be infected with and transmit CHIKV, CHIKV is able to evolve in these mosquitoes, and that host salivary factors display population-specific diversity. Taken together, these studies highlight the need to study how distinct mosquito populations control viral infections, both at the virus and host level.