A. quadriannulatus mosquito feeding. Lateral view of a female Anopheles quadriannulatus mosquito feeding on human skin. It has used its sharp, needle-like labrum to extract blood that is seen in its abdomen, forming a blood meal. As a member of the A. gambiae species complex, A. quadriannulatus is a known vector for the parasitic disease malaria. Malaria is caused by the Plasmodium falciparum parasite, which is transmitted into the bloodstream by mosquito bites. Malaria results in cyclic fevers and can kill. It affects millions of people in tropical and subtropical regions of the world.