The malaria parasite, Plasmodium falciparum, increases the frequency of multiple feeding of its mosquito vector, Anopheles gambiae.
It has often been suggested that vector-borne parasites alter their vector's feeding behaviour to increase their transmission, but these claims are often based on laboratory studies and lack rigorous testing in a natural situation. We show in this field study that the malaria parasite, Plasmodium falciparum, alters the blood-feeding behaviour of its mosquito vector, Anopheles gambiae s.l., in two ways. First, mosquitoes infected with sporozoited, the parasite stage that is transmitted from the mosquito to a human, took up larger blood meals than uninfected mosquitoes. Whereas 72% of the uninfected mosquitoes had obtained a full blood meal, 82% of the infected ones had engorged fully. Second, mosquitoes harbouring sporozoites were more likely to bite several people per night. Twenty-two per cent of the infected mosquitoes, but only 10% of the uninfected mosquitoes, contained blood from at least two people. We conclude that the observed changes in blood-feeding behaviour allow the parasite to spread more rapidly among human hosts, and thus confirm that the parasite manipulates the mosquito to increase its own transmission.
Koella
J C
JC
Department of Zoology, University of Aarhus, Denmark. jacob.koella@biology.aau.dk
Sørensen
F L
FL
Anderson
R A
RA
D000818:Animals; D000852:Anopheles / Q000469:parasitology* / Q000502:physiology*; D005247:Feeding Behavior; D006790:Host-Parasite Interactions; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000502:physiology*