In addition to those occurring in humans, Plasmodium species occur in many other mammals and avians. The life cycle involves sporozoites being introduced with the bite of the infected mosquito. Merozoites enter either new hepatic cells or RBCs. If gametes are picked up along with the blood meal taken by a susceptible mosquito, these gametocytes initiate the sexual cycle. A-sexual division results in sporozoites that migrate to the salivary glands and are capable of producing an infection when inoculated by the feeding mosquito.
Schizogony occurs in endothelial cells of blood vessels.
Hippobosid flies are the typical vector for most species. Most cases are asymptomatic with a large percentage of wild birds, especially morning doves, being infected. Concurrent infections with Leucocytozoon spp are common. This is another malaria-like organism infecting birds. There are several important species in birds with some being pathogenic, especially in young birds.