Malaria host manipulation increases probability of mosquitoes feeding on humans

Abstract

Cite as: Duncan A. Malaria host manipulation increases probability of mosquitoes feeding on humans. Cohuet A, Dabire KR, and Lefevre T. Field evidence for manipulation of mosquito host selection by the human malaria parasite, Plasmodium falciparum. bioRxiv, 207183 ver. 6 peer-reviewed and recommended by PCI Evol Biol (2018). Parasites can manipulate their host's behaviour to ensure their own transmission. These manipulated behaviours may be outside the range of ordinary host activities [5], or alter the crucial timing and/or location of a host's regular activity. Vantaux et al. show that the latter is true for the human malaria parasite, Plasmodium falciparum [6]. They demonstrate that three species of Anopheles mosquito were 24% more likely to choose human hosts, rather than other vertebrates, for their blood feed when they harboured transmissible stages (sporozoites) compared to when they were uninfected, or infected with non-transmissible malaria parasites [6]. Host choice is crucial for the malaria parasite Plasmodium falciparum to complete its life-cycle, as their host range is much narrower than the mosquito's for feeding; P. falciparum can only develop in hominids, or closely related apes [4]. The study only shows this stage-dependent parasite manipulation retrospectively (by identifying host type and parasite stage in mosquitoes after their blood feed [6]). There was no difference in the preferences of infectious (with sporozoites) or un-infectious (infected without sporozoites, or uninfected) mosquitoes between human versus cow hosts in a choice test [6]. This suggests that the final decision about whether to feed occurs when the mosquito is in close range of the host. This, coupled with previous findings, shows that vector manipulation is a fine-tuned business, that can act at multiple stages of the parasite life-cycle and on many behaviours [2]. Indeed,