Differential Susceptibility and Innate Immune Response of and to the Haitian Strain of the Mayaro Virus.

Mayaro (MAYV) is an emerging arthropod-borne virus belonging to the Alphavirus genus of the family. Although forest-dwelling mosquitoes have been considered as its main vector, the virus has also been detected in circulating mosquitoes. Here we assess the susceptibility of and to infection with MAYV and their innate immune response at an early stage of infection. was more susceptible to infection with MAYV than Analysis of transcript levels of twenty immunity-related genes by real-time PCR in the midgut of both mosquitoes infected with MAYV revealed increased expression of several immune genes, including CLIP-domain serine proteases, the anti-microbial peptides defensin A, E, cecropin E, and the virus inducible gene. The regulation of certain genes appeared to be species-dependent. Infection of with MAYV resulted in increased levels of myeloid differentiation2-related lipid recognition protein () transcripts, as compared to . Increased expression levels of thio-ester-containing protein 22 () and Niemann-Pick type C1 () gene transcripts were observed in infected , but not . The differences in these gene expression levels during MAYV infection could explain the variation in susceptibility observed in both mosquito species.