Why has the Zika virus (ZIKV) not wreaked as much devastation in Africa, its continent of origin, as in America?
Outside of Africa, this flavivirus is transmitted by a ubiquitous mosquito subspecies, Aedes aegypti aegypti, which emerged from the African precursor subspecies A. aegypti formosus and has acquired a preference for human blood and a peridomestic lifestyle, researchers said in one of Science on study published November 20, 2020.
Aubry et al. tested 14 laboratory mosquito colonies for their relative susceptibility to ZIKV. The quantitative mapping of the trait locus showed differences on chromosome 2 between mosquitoes from Gabon and Guadeloupe.
Experiments with mouse infections have shown that African mosquitoes transmit a smaller virus inoculum than South American insects. Increased susceptibility, coupled with A. aegypti aegypti’s ability to reproduce in a discarded object that contains water, has compounded the problem of this virus as it has circled the world.
The Aedes aegypti mosquito is a major arbovirus vector native to Africa that has invaded most of the world’s tropical belt over the past four centuries, having developed a “native” form that targets human biting and specialized in breeding in water storage tanks.
The recent development and global expansion of A. aegypti therefore promoted the development of arboviruses not only through increased vector-host contact, but also as a result of increased vector susceptibility.
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