Isospora Species of Animals

Name

Greek: isos = identical; sporos = seed, spore; kystis = cyst, capsule.

Geographic Distributions/Epidemiology

The isospores are worldwide found as parasites of many groups of vertebrates. Their abundance in single infected hosts may reach very high numbers, as well as the rate of infection among given host population may reach 90 %.

Morphology/Life Cycle

In the present overlook only a few species are considered out of a number of several hundreds. The life cycle has the same phases (schizogony, gamagony, sporogony) like the Eimeria species, which are as numerous. The difference is that in Isospora species the oocysts include two sporocysts with four sporozoites (Fig. 1), while in oocysts of Eimeria species four sporocysts with two sporozoites occur (Coccidia). The oocysts are excreted in an unsporulated state and form their infectious stages in species-specific and temperature-dependent times outside of the host (=sporulation). Due to the extremely resistant oocyst wall the...