Over 500 species are in this order, organised into four families: the Garniidae, the Haemoproteidae, the Leucocytozoidae, and the Plasmodiidae. The majority of the species lie within three genera: Haemoproteus, Leucocytozoon, and Plasmodium.
The Haemoproteidae and the Plasmodiidae both produce pigment. These families have been placed in the suborder Laveraniina. Neither the Haemoproteidae nor the Leucocytozoidae have an asexual cycle in the peripheral blood. The Garniidae do not produce pigment, but do have an asexual cycle in the blood.
The genus Mesnilium is the only group that infects fish. The genus has a single species and has been reported only once. IThis genus may have been mistakenly placed in this genus. DNA studies are likely to be needed to clarify this point.
Several genera infect mammals: Bioccala, Biguetiella, Dionisia, Hepatocystis, Plasmodium,
Polychromophilus, Nycteria, and Rayella.
The insect vectors of Hepatocystis, Plasmodium and Polychromophilus are Ceratopogonidae, Culicidae, and Nycteribiidae, respectively. The vectors of Nycteria and Rayella are currently unknown. Bioccala also uses Nycteribiidae as its insect vector.
Rayella is thought to have originated from Hepatocystis.[4][5]
Morrison has shown using molecular data that the Haemosporidia are nested within the gregarines and that this clade is distinct from the piroplasms.[6] This latter clade is a sister group of the coccidians.
^Lainson R, Landau I, Shaw JJ (December 1971). "On a new family of non-pigmented parasites in the blood of reptiles: Garniidae fam. nov., (Coccidiida: Haemosporidiidea). Some species of the new genus Garnia". Int. J. Parasitol. 1 (3–4): 241–4. doi:10.1016/0020-7519(71)90027-0.
^Garnham PCC (1966). Malaria parasites and other Haemosporidia. Oxford: Blackwell Scientific. ISBN978-0397601325.
^Mattingly PF (1983). "The paleogeography of mosquito-borne disease". Biological Journal of the Linnean Society. 19 (2): 185–210. doi:10.1111/j.1095-8312.1983.tb00783.x.
