Plasmodium, the causative agent of malaria, was discovered by Charles Laveran in 1880. Lancisi first suspected a relationship between mosquito and malaria. Ronald Ross (1897) discovered (confirmed) relationship between malaria and mosquito. In 1897 Ross discovered oocytes of Plasmodium in the stomach of mosquito. He got Nobel Prize in 1902. Grassi (1898) described the life history of the parasite in female Anopheles mosquito. Shortt and Garnham (1948) are associated with the discovery of life cycle of malarial parasite. Malaria means 'Bad air'. Causative agent of malaria is Plasmodium. There are 60 species of Plasmodium. Only four species cause malaria in man. They are Plasmodium vivex (the most common species), P. ovale, P. malariae and P. falciparum. Plasmodium belongs to class Sporozoa of phylum Protozoa. Plasmodium is an endoparasite, blood parasite, intracellular parasite, pathogenic parasite and digenetic parasite. Carrier or vector is female Anopheles. Asexual cycle is passed in man by a process termed schizogony (schizogony in lever and RBCs). Schizogony is a type of multiple fission.
Plasmodium vivax (malaria parasite) - a digenetic parasite protozoan
Organisms that live on or in other living organisms and obtain their food from them are called parasite. The organisms on or in which parasite live are called hosts. Plasmodium is a protozoan parasite and spends its life in two hosts - partly in man where the adult parasite lives; man is, therefore, the primary or definitive host and in whom it causes malaria fever and partly in various species of mosquitoes of the genus Anopheles. Mosquito is the intermediate host because a very important part of its life-history is passed in it. Some author takes mosquitoes as a definite host. Having two host, (digenetic life cycle). Plasmodium ensures continuance of its existence in the event of death of any one host. The anopheles carries the malarial parasite from an infected human host to a fresh human host whom its bites, hence the mosquito is also a vector or carrier of disease. Monkeys have malarial parasite in their blood but themselves do not suffer from malaria, hence they act as reservoir hosts. Mosquitoes may transmit the parasite from monkeys to man.