Synonyms: Gastrocystis gilruthi, Globidium gilruthi.
Hosts: Sheep, goat.
Location: Abomasum, seldom small intestine.
Geographic Distribution: Worldwide.
Prevalence: This form is very common in Europe. Chatton (1910) and Triffitt (1928) found it in the abomasa of almost all the sheep they examined in France and England, respectively. Alicata (1930) found it in 9% of 78 sheep in Indiana, 11% of 101 sheep from West Virginia and 8% of 72 sheep from Idaho. It has also been seen in Montana, Wyoming, Michigan (Morgan and Hawkins, 1952) and Illinois. Sarwar (1951) found it in 34% of the sheep and goats slaughtered at the Lahore, Pakistan abattoir, and found it in as many as 94% in other parts of East Punjab. Soliman (19 58) found it in 18% of 250 sheep and 28% of 150 goats slaughtered in Egypt. Soliman (1960) found it in 32% of 425 sheep and 40% of 240 goats in the Sudan. Rac and Willson (1959) reported it in Australia.
Morphology: Only the schizonts and merozoites of this form have been described. The schizonts occur in the connective tissue of the abomasal wall. They are 300 to 700 u long and 300 to 465 u wide, and are easily visible to the naked eye as whitish nodules. The host cell nucleus is flattened and greatly enlarged. The mature schizonts are filled with many thousands of crescent-shaped merozoites about 4.5 to 7.5 u long and 1.2 to 2.0 u wide. One end of the merozoites is rounded and the other pointed. The nucleus is near the broad end, and a heavily staining granule is in the center.
These schizonts are undoubtedly those of a species of Eimeria presently known from its oocysts alone, but we do not know which species it is. Reichenow (1940) said that it was very probably E. intricata. Becker (1956) agreed and, since the specific name gilruthi has priority, synonymized E. intricata with it. However, Kotlan, Pellerdy and Versenyi (1951, 1951a) found two types of giant schizonts in sheep. One type, which measured 64 to 256 by 48 to 179 u and contained straight, slender merozoites 10 to 12 u long, they found to be those of E. parva. The other type of schizont was larger and contained merozoites about 16 u long which were bent like a hoe at one end ("hacken-formigen"). These they said were those of E. intricata. However, they saw both schizonts in the small intestine and not in the abomasum, and they used only 2 lambs in their work. Hence, it is felt best for the present not to attempt to assign the gilruthi schizonts to any other species of Eimeria.