The Apicomplexa are organisms of a large phylum of mainly parasitic alveolates. Most possess a unique form of organelle structure that comprises a type of (non-photosynthetic) plastid called an apicoplast—with an apical complex membrane. The organelle's apical shape is an adaptation that the apicomplexan applies in penetrating a host cell.
Plasmodium is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of Plasmodium species involve development in a blood-feeding insect host which then injects parasites into a vertebrate host during a blood meal. Parasites grow within a vertebrate body tissue before entering the bloodstream to infect red blood cells. The ensuing destruction of host red blood cells can result in malaria. During this infection, some parasites are picked up by a blood-feeding insect, continuing the life cycle.
Plasmodium vivax is a protozoal parasite and a human pathogen. This parasite is the most frequent and widely distributed cause of recurring malaria. Although it is less virulent than Plasmodium falciparum, the deadliest of the five human malaria parasites, P. vivax malaria infections can lead to severe disease and death, often due to splenomegaly. P. vivax is carried by the female Anopheles mosquito; the males do not bite.
Plasmodium ovale is a species of parasitic protozoon that causes tertian malaria in humans. It is one of several species of Plasmodium parasites that infect humans, including Plasmodium falciparum and Plasmodium vivax which are responsible for most cases of malaria in the world. P. ovale is rare compared to these two parasites, and substantially less dangerous than P. falciparum.
Plasmodium malariae is a parasitic protozoan that causes malaria in humans. It is one of several species of Plasmodium parasites that infect other organisms as pathogens, also including Plasmodium falciparum and Plasmodium vivax, responsible for most malarial infection. Found worldwide, it causes a so-called "benign malaria", not nearly as dangerous as that produced by P. falciparum or P. vivax. The signs include fevers that recur at approximately three-day intervals – a quartan fever or quartan malaria – longer than the two-day (tertian) intervals of the other malarial parasite.
Plasmodium knowlesi is a parasite that causes malaria in humans and other primates. It is found throughout Southeast Asia, and is the most common cause of human malaria in Malaysia. Like other Plasmodium species, P. knowlesi has a life cycle that requires infection of both a mosquito and a warm-blooded host. While the natural warm-blooded hosts of P. knowlesi are likely various Old World monkeys, humans can be infected by P. knowlesi if they are fed upon by infected mosquitoes. P. knowlesi is a eukaryote in the phylum Apicomplexa, genus Plasmodium, and subgenus Plasmodium. It is most closely related to the human parasite Plasmodium vivax as well as other Plasmodium species that infect non-human primates.
Plasmodium berghei is a single-celled parasite causing rodent malaria. It is in the Plasmodium subgenus Vinckeia.
Plasmodium azurophilum is a species of the genus Plasmodium. Like all species in this genus it is a parasite of both vertebrates and insects. The vertebrate hosts are anole lizards.
Vinckeia is a subgenus of the genus Plasmodium — all of which are parasitic alveolates. The subgenus Vinckeia was created by Cyril Garnham in 1964 to accommodate the mammalian parasites other than those infecting the primates.
Plasmodium eylesi is a parasite of the genus Plasmodium subgenus Plasmodium.
Plasmodium beltrani is a parasite of the genus Plasmodium subgenus Sauramoeba. As in all Plasmodium species, P. beltrani has both vertebrate and insect hosts. The vertebrate hosts for this parasite are spiny lizards.
Plasmodium basilisci is a parasite of the genus Plasmodium subgenus Carinamoeba.
Avian malaria is a parasitic disease of birds, caused by parasite species belonging to the genera Plasmodium and Hemoproteus. The disease is transmitted by a dipteran vector including mosquitoes in the case of Plasmodium parasites and biting midges for Hemoproteus. The range of symptoms and effects of the parasite on its bird hosts is very wide, from asymptomatic cases to drastic population declines due to the disease, as is the case of the Hawaiian honeycreepers. The diversity of parasites is large, as it is estimated that there are approximately as many parasites as there are species of hosts. As research on human malaria parasites became difficult, Dr. Ross studied avian malaria parasites. Co-speciation and host switching events have contributed to the broad range of hosts that these parasites can infect, causing avian malaria to be a widespread global disease, found everywhere except Antarctica.
Plasmodium acuminatum is a species in the genus Plasmodium subgenus Lacertamoeba.
Plasmodium neusticuri is a parasite of the genus Plasmodium.
Hematozoa is a subclass of blood parasites of the Apicomplexa clade. Well known examples include the Plasmodium spp. which cause malaria in humans and Theileria which causes theileriosis in cattle. A large number of species are known to infect birds and are transmitted by insect vectors. The pattern in which Haematozoa infect a host cell depends on the genera of the blood parasite. Plasmodium and Leucozytozoon displace the nucleus of the host cell so that the parasite can take control of the cell where as Hemoproteus completely envelops the nucleus in a host cell.
Plasmodium fieldi is a parasite of the genus Plasmodium sub genus Plasmodium found in Malaysia. This species is related to Plasmodium ovale and Plasmodium simiovale. As in all Plasmodium species, P. fieldi has both vertebrate and insect hosts. The vertebrate hosts for this parasite are primates.
Plasmodium vaughani is a parasite of the genus Plasmodium, and the type species of the subgenus Novyella. As in all Plasmodium species, P. vaughani has both vertebrate and insect hosts. The vertebrate hosts for this parasite are birds.
Nycteria is a genus of protozoan parasites that belong to the phylum Apicomplexa. It is composed of vector-borne haemosporidian parasites that infect a wide range of mammals such as primates, rodents and bats. Its vertebrate hosts are bats. First described by Garnham and Heisch in 1953, Nycteria is mostly found in bat species where it feeds off the blood of their hosts and causes disease. Within the host, Nycteria develops into peculiar lobulated schizonts in parenchyma cells of the liver, similarly to the stages of Plasmodium falciparum in the liver. The vector of Nycteria has been hard to acquire and identify. Because of this, the life cycle of Nycteria still remains unknown and understudied. It has been suggested that this vector could be an arthropod other than a mosquito or the vector of most haemosporidian parasites.
Plasmodium cynomolgi is an apicomplexan parasite that infects mosquitoes and Asian Old World monkeys. In recent years, a number of natural infections of humans have also been documented. This species has been used as a model for human Plasmodium vivax because Plasmodium cynomolgi shares the same life cycle and some important biological features with P. vivax.
