The genera Eimeria (sporulated oocyst contains four sporocysts) and Isospora (sporulated oocyst contains two sporocysts) contain many species that infect a wide variety of birds, mammals and reptiles, but almost all are species host-specific. Infections occur throughout the world.

The oocysts of what was later called Eimeria stiedai were first seen by the pioneering Dutch microscopist Antonie van Leeuwenhoek (1632–1723) in the bile of a rabbit in 1674. The genus is named after the German zoologist Theodor Eimer (1843–1898).

Coccidiosis is a worldwide ovine problem caused by the genus Eimeria, protozoal intracellular parasites of the intestinal epithelial cells. They cause considerable disease and economic loss. Under most sheep production systems, all, or nearly all, animals are exposed to some Eimeria spp, although most infections are inapparent.

The Eimeria life cycle has basically two stages: the exogenous phase (sporogony) and the endogenous phase (schizogony and gametogony) . The initial infective unit of all Eimeria spp. is the sporozoite stage, which is a banana-shaped motile cell.

Eimeria spp. [these species cause coccidiosis in vertebrates, especially herbivores] Parasite morphology: Coccidian parasites form three developmental stages: schizonts, gamonts and oocysts. Schizonts range in size depending on parasite species, location in …

Sporulated oocysts of Eimeria contain four sporocysts, each with two sporozoites. An eimerian species was one of the first protists ever visualized when Antoni van Leeuwenhoek saw what surely were oocysts of Eimeria steidai (Lindemann, 1895) in the bile of a rabbit in 1674.

The prerequisite for the control and treatment of coccidiosis in poultry is to correctly identify the presence of disease. Two of the most widely used methods for this purpose are the identification and enumeration of oocysts, and the identification of lesions in the intestine.

According to the morphology of the recorded oocysts, five species were found. Eimeria necatrix was the first species discovered, and it was distinguished by oblong, ovoid-shaped oocysts with double-layered walls that measured 20 (23–23) and 17 (16–20) μm.

2022年9月1日 · Purified field samples were analyzed to count Eimeria oocysts using both manual McMaster technique and ImageJ methods. Oocysts were classified by size (small, medium, and large).

In this review, we discuss different aspects of the life cycle and stages of Eimeria species, focusing on cellular structures and organelles typical of the coccidian family as well as genus-specific features, complementing some ‘unknowns’ with what is described in the closely related coccidian Toxoplasma gondii.