Eucoccidiorida is an order of microscopic, spore-forming, single-celled parasites belonging to the apicomplexan class Conoidasida. Protozoans of this order include parasites of humans, and both domesticated and wild animals including birds. Among these parasites are the Toxoplasma gondii that cause toxoplasmosis and Isospora belli, which results in isosporiasis.
Definition
This is the largest order in the class Conoidasida and contains those species that all undergo merogony (asexual), gametogony (sexual) and sporogony (spore formation) during their life cycle
Genera
There are 19 families, 3 subfamilies and 69 genera recognised in this order. In alphabetical order the genera are:
Adelea, Adelina, Aggregata, Alveocystis, Atoxoplasma, Babesiosoma, Barrouxia, Besnoitia, Calyptospora, Caryospora, Caryotropha, Chagasella, Choleoeimeria, Cryptosporidium, Crystallospora, Cyclospora, Cyrilia, Cystoisospora, Dactylosoma, Desseria, Diaspora, Dorisa, Dorisiella, Eimeria, Elleipsisoma, Epieimeria, Frenkelia, Ganapatiella, Gibbsia, Goussia, Gousseffia, Grasseella, Hammondia, Haemogregarina, Hemolivia, Hepatozoon, Hoarella, Hyaloklossia, Isospora, Ithania, Karyolysus, Klossia, Klossiella, Lankesterella, Legerella, Margolisiella, Mantonella, Merocystis, Nephroisospora, Neospora, Octosporella, Orcheobius, Ovivora, Pfeifferinella, Polysporella, Pseudoklossia, Pythonella, Rasajeyna, Sarcocystis, Schellackia, Selenococcidium, Selysina, Sivatoshella, Skrjabinella, Spirocystis, Toxoplasma, Tyzzeria, Wenyonella
Notes
Among the heteroxenous and cyst forming genera are: Besnoitia, Cystoisospora, Frenkelia, Hammondia, Neospora, Sarcocystis and Toxoplasma.
Taxonomy
The taxonomy of this group is complex and only partly understood. Two major clades have been identified: the isosporoid coccidia (Toxoplasma, Neospora, Isospora [in part], and Sarcocystis) and a second clade containing Lankesterella, Caryospora and the eimeriid coccidia (Cyclospora, Isospora [in part] and Eimeria).[1] Isospora is more closely related to the Toxoplasma/Neospora clade than to Sarcocystis.[2]
Families
There are ~1,000 species in the genus Eimeria.
Some of the genera have been organised into families.
- Family Sarcocystidae
- Genera
- Besnoitia
- Cystoisospora
- Neospora
- Sarcocystis
- Toxoplasma
