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.
Coccidia (Coccidiasina) are a subclass of microscopic, spore-forming, single-celled obligate intracellular parasites belonging to the apicomplexan class Conoidasida. As obligate intracellular parasites, they must live and reproduce within an animal cell. Coccidian parasites infect the intestinal tracts of animals, and are the largest group of apicomplexan protozoa.
Eimeria is a genus of apicomplexan parasites that includes various species capable of causing the disease coccidiosis in animals such as cattle, poultry and smaller ruminants including sheep and goats. Eimeria species are considered to be monoxenous because the life cycle is completed within a single host, and stenoxenous because they tend to be host specific, although a number of exceptions have been identified. Species of this genus infect a wide variety of hosts. Thirty-one species are known to occur in bats (Chiroptera), two in turtles, and 130 named species infect fish. Two species infect seals. Five species infect llamas and alpacas: E. alpacae, E. ivitaensis, E. lamae, E. macusaniensis, and E. punonensis. A number of species infect rodents, including E. couesii, E. kinsellai, E. palustris, E. ojastii and E. oryzomysi. Others infect poultry, rabbits and cattle. For full species list, see below.
The gregarines are a group of Apicomplexan alveolates, classified as the Gregarinasina or Gregarinia. The large parasites inhabit the intestines of many invertebrates. They are not found in any vertebrates. Gregarines are closely related to both Toxoplasma and Plasmodium, which cause toxoplasmosis and malaria, respectively. Both protists use protein complexes similar to those that are formed by the gregarines for gliding motility and for invading target cells. This makes the gregarines excellent models for studying gliding motility, with the goal of developing treatment options for both toxoplasmosis and malaria. Thousands of different species of gregarine are expected to be found in insects, and 99% of these gregarine species still need to be described. Each insect species can be the host of multiple gregarine species. One of the most-studied gregarines is Gregarina garnhami. In general, gregarines are regarded as a very successful group of parasites, as their hosts are distributed over the entire planet.
The dwarf musk deer or Chinese forest musk deer is an artiodactyl native to southern and central China and northernmost Vietnam. The species name is after the collector Mikhail Mikhailovich Berezovsky. On June 14, 1976, China entered the dwarf musk deer onto its endangered species list. Four subspecies are recognized:
Adeleorina is a suborder of parasites in the phylum Apicomplexa.
Eimeriidae is a family of Apicomplexa. It contains the following genera:
Choleoeimeria is a genus of alveolate parasites that infect the biliary tracts of reptiles. Morphologically they are similar to the Eimeria, to whom they are closely related. The genus was described in 1989 by Paperna and Landsberg.
Acroeimeria is a genus of parasites that contains those species which initially develop immediately beneath the brush-border of the intestinal epithelium, but the meronts and gamonts of which are early on extruded to form a layer on the surface of the gut mucosa. Morphologically they are similar to the Eimeria to which they are closely related. The genus was described in 1989 by Paperna and Landsberg.
Goussia is a taxonomic genus, first described in 1896 by Labbé, containing parasitic protists which largely target fish and amphibians as their hosts. Members of this genus are homoxenous and often reside in the gastrointestinal tract of the host, however others may be found in organs such as the gallbladder or liver. The genera Goussia, as current phylogenies indicate, is part of the class Conoidasida, which is a subset of the parasitic phylum Apicomplexa; features of this phylum, such as a distinct apical complex containing specialized secretory organelles, an apical polar ring, and a conoid are all present within Goussia, and assist in the mechanical invasion of host tissue. The name Goussia is derived from the French word gousse, meaning pod. This name is based on the bi-valve sporocyst morphology which some Goussians display. Of the original 8 classified Goussians, 6 fit the “pod” morphology. As of this writing, the genera consists of 59 individual species.
Achromatorida is an order of non-pigmented intraerythrocytic parasitic alveolates belonging to the subclass Haemosporidiasina. The order was created by Jacques Euzéby in 1988.
Cyclospora is a genus of apicomplexan parasites. It includes the species Cyclospora cayetanensis, the causative agent of cyclosporiasis. Members of Cyclospora are characterized as having oocysts with two sporocysts, each containing two sporozoites.
Aggregata is a genus of parasitic alveolates belonging to the phylum Apicomplexa.
Frenkelia is a genus of parasites in the phylum Apicomplexa. The species in this genus infect the gastrointestinal tracts of birds of prey and the tissues of small rodents.
Calyptospora is a genus of parasitic protozoa in the phylum Apicomplexa.
Epieimeria is a genus of parasitic alveaolates of the phylum Apicomplexa.
Hyaloklossia is a genus of parasitic alveolates in the phylum Apicomplexa. Only two species in this genus are currently recognised.
The Neogregarinorida are an order of parasitic alveolates in the phylum Apicomplexa. Species in this order infect insects and are usually found in the fat body, hemolymph, hypodermis, intestine or Malpighian tubules. The most common site of infection is the fat body: many species are pathogenic for their hosts.
The Eugregarinorida are the most large and diverse order of gregarines — parasitic protists belonging to the phylum Apicomplexa. Eugregarines are found in marine, freshwater and terrestrial habitats. These species possess large trophozoites that are significantly different in morphology and behavior from the sporozoites. This taxon contains most of the known gregarine species.
Aseptatorina is a suborder of parasitic alveolates of the phylum Apicomplexa
