Malaria parasite. Image 5 of 10. Coloured transmission electron micrograph (TEM) of a sexual malaria ookinete in a mosquito gut wall. The ookinete (blue, Plasmodium sp.) is penetrating the gut (lower frame) of the mosquito (Anopheles sp.). This stage occurs after the sexual gametes, formed after the parasites are ingested by a feeding mosquito, fuse. The ookinete forms an oocyst in the wall, in which sporozoites, which infect humans, grow. Malaria later invades human red blood cells, causing fevers and anaemia. Magnification unknown. For the complete malaria parasite life cycle, see images M210/197-206.