Isospora Aksaica

Host: Ox.

Location: Unknown. Oocysts found in feces.

Geographic Distribution: USSR (Kazakhstan).

Prevalence: Unknown. This species was found only in calves 12 to 30 days old.

Morphology: The oocysts are 26 u in diameter, spherical, dark silver under low magnification and light, pinkish grey under high. The oocyst wall is 1.6 u thick, smooth and double-contoured, with a light blue outer layer and a greenish, dingy rose inner layer. The sporocysts are ellipsoidal or spherical, 22 by 15 u. Micropyle, oocyst residuum and sporocyst residuum are presumably absent. Polar granules are possibly present. The sporozoites are spherical, bean-shaped or ellipsoidal, 15 by 11 u.

Life Cycle: Unknown.

Pathogenesis: Unknown.

Remarks: There is a question whether this is actually a valid species of bovine coccidium or whether it is a pseudoparasite, i.e., an avian or other foreign coccidium which the cattle had ingested along with its host’s feces. Further work will be necessary to decide this point. The subjacent discussion of the Isospora species found by Levine and Mohan (1960) in cattle has a bearing on I. aksaica also.