Malaria. Coloured scanning electron micrograph (SEM) of red blood cells and Plasmodium falciparum protozoa. These protozoa (yellow) cause malaria. The disease is spread by bites from infected tropical mosquitoes (Anopheles sp.). At this stage the plasmodia are in their sex form, and are known as gametocytes. They stay in the bloodstream waiting to be sucked up by a mosquito, where they breed and can infect other people through the mosquito's bite. The disease causes a lack of red blood cells, leading to anaemia, and mis-shapen infected blood cells can block blood vessels, leading to kidney failure, coma, and death. Magnification: x2450 at 6x7cm size.