MALARIA Malaria, the most important protozoa disease in humans, is caused by the genus Plasmodium. Four species are pathogenic, P. vivax, P. falciparum, P. malariae and P. ovale, of which the first two occur in India. Mosquitoes usually breed in edges of streams, water tanks, pits, cisterns and overhead tanks fountains burrowed pits, pools, ponds,