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Surface and Subtext: Literature, Research, Writing (2nd Edition)
No full textOER textbook for ENGL 20
Effects of Heterogeneous Microclimates on the Vector Competence of Aedes aegypti
No full textAedes aegypti is a prolific vector of medically important arthropod-borne viruses (arboviruses) including yellow fever virus (YFV), dengue virus serotypes 1-4 (DENV1-4), chikungunya virus (CHIKV), and Zika virus (ZIKV). Our understanding of the transmission dynamics of mosquito-borne viral diseases is limited by the paucity of information about the molecular mechanisms underlying the susceptibility of vector species to arboviral infection. Notably, there is a dearth of information on how temperatures present in mosquito breeding and resting sites influence the innate immune systems of these ectothermic insects. Previous work has shown that Ae. aegypti reared at a colder temperature exhibited evidence of an impaired small interfering RNA (siRNA) pathway, the primary antiviral pathway in mosquitoes, which correlated with an increased susceptibility to arbovirus infection. To further investigate the role of the siRNA pathway in the transmission of ZIKV and its potential relationship with temperature dependent changes in vector competence, we conducted experiments using Ago2 and Dcr2 knockout mutant Ae. aegypti lacking a functional siRNA pathway and a transgenic siRNA ���sensor��� strain reared under heterogenous temperature conditions over various life stages. We observed an inhibition of the siRNA pathway in adult Ae. aegypti reared at temperatures as high as 25��C, which correlated with significant increases in midgut infection prevalence and the development of systemic infection following ingestion of ZIKV. Further, we found that this temperature dependent inhibition of RNA silencing and increased vector competence was associated with exposure to lower temperatures during pupal development. Temperatures below 25��C were routinely recorded in microhabitats surrounding mosquito trap sites throughout the greater metropolitan area of Houston, Texas, suggesting that mosquitoes may experience these temperatures in nature. We observed that disruptions in essential genes in the siRNA pathway resulted in increased dissemination of virus from the midgut but did not increase transmission of ZIKV. Overall, our findings indicate that while the siRNA pathway may not be the major contributor to observed temperature dependent changes in vector competence, Ae. aegypti exposed to diurnal temperatures of 25��C or lower over the short and relatively immobile pupal stage may have a greater potential to transmit ZIKV
