Postdoctoral fellow
In the ArboVec project we assess the differential vectorial efficiency of Aedes and Anopheles mosquitoes for the transmission of arboviruses. While Anopheles mosquitoes are the main vectors of human malaria, they could also be the primary vector of only one arbovirus, the alphavirus O’nyong nyong (ONNV, family Togaviridae). In contrast, Aedes mosquitoes transmit many arboviruses such as dengue (DENV, family Flaviviridae) Zika (ZIKV, family Flaviviridae), chikungunya (CHIKV, family Togaviridae) but not human malaria. ONNV is very phylogenetically close to the Aedes-transmitted CHIKV, and is an emergent infectious disease that has been responsible for millions of cases during known epidemics across Africa, and many more undiagnosed cases. Both CHIKV and ONNV were first described in the 1950s as African infections with similar symptoms. By the 1960s, CHIKV was detected in Asia, with the first autochthonous cases in Europe in 2007, and is now a globally emerging pathogen. However, ONNV has not yet been detected outside of Africa, but the potential for emergence exists because Anopheles mosquitoes are widespread.It is a biological puzzle that almost all arbovirus transmission is mediated by Aedes aegypti and relatives while Anopheles transmit just a single known arbovirus. ONNV transmission is the exception that indicates arbovirus transmission by Anopheles. Both Ae. aegypti and An. coluzzii are strongly human-biting in nature, and both are exposed to arboviruses, so behavior does not explain the difference in vector specificity. The easiest hypothesis is that antiviral mechanisms are more efficient in Anopheles than Aedes. Here in the ArboVec project, we will compare the antiviral mechanisms of the African malaria and ONNV vector An. coluzzii, and the efficient arbovirus vector, Ae. aegypti. Dissecting host mechanisms of virus interaction will reveal the biology underlying the differential efficiency of arbovirus transmission by Anopheles and Aedes. The results provided will also indicate the level of risk that an arbovirus could shift between hosts to exploit Anopheles as a new vector, or that ONNV, which is more prevalent than CHIKV in Africa, could exploit Aedes mosquitoes. Vector shift was previously demonstrated for CHIKV between Aedes aegypti and Aedes albopictus species. Knowledge of antiviral barriers in Anopheles may also provide new tools to raise the barrier to arbovirus transmission by the more efficient culicine (Aedes and Culex) vectors.
