The ultrastructure of endogenous stages of Eimeria ninakohlyakimovae was
observed in epithelial cells of cecum and colon crypts from a goat
experimentally infected with 2.0 x 10^5 oocysts/kg. The secondary meronts
developed above the nucleus of the host cell. The nucleus first divides and
merozoites then form on the surface of multinucleated meronts. Free
merozoites in the parasitophorous vacuole present a conoid, double
membrane, one pair of rhoptries, micronemes, micropore, anterior and
posterior polar ring, a nucleus with a nucleolus and peripheral chromatin.
The microgamonts are located below the nucleus of the host cell and contain
several nuclei at the periphery of the parasite. The microgametes consist
of a body, a nucleus, three flagella and mitochondria. The macrogamonts
develop below the nucleus of the host cell and have a large nucleus with a
prominent nucleolus. The macrogametes contain a nucleus, wall-forming
bodies of type I and type II. The young oocysts present a wall containing
two layers and a sporont.
