Malaria parasites. Image 3 of 10. Coloured transmission electron micrograph (TEM) of malaria-infected red blood cells in a human liver. The malaria (Plasmodium sp.) parasites (merozoites, brown, for example upper left) invade the red blood cells after the sporozoite stage is injected into the host by a mosquito (Anopheles sp.). There they undergo asexual replication, forming many more merozoites. These may re-invade the red blood cells, causing cyclic fevers, anaemia or even death. Magnification: x19,100 at 6x7cm size. For the complete malaria parasite life cycle, see images M210/207-216.