Isospora bigemina (fig. 75) appears to occur also in man, for Virchow published a case which was communicated to him by Kjellberg, and attributed the illness to this parasite.[189] Possibly also it would be more correct to ascribe the observation of Railliet and Lucet, which is mentioned under “Human Intestinal Coccidiosis,” p. [148], to this species, as the Coccidia in that case were distinguished by their diminutive size (length 15 µ, breadth 10 µ). The case communicated by Grunow may also possibly refer to Isospora bigemina.[190] Roundish or oval structures of 6 µ to 13 µ in diameter occurred in the mucous membrane of the gut and in the fæces of a case of enteritis.
Fig. 75.—Isospora bigemina, Stiles (from the intestine of a dog). a, Piece of an intestinal villus beset with Isospora, slightly enlarged; b, Isospora bigemina (15 µ in diameter), shortly before division; c, divided; d, each portion encysted forming two spores; e, four sporozoites in each part, on the left seen in optical section, together with a residual body—highly magnified. (After Stiles.)
Doubtful Species.
In literature many other statements are found as to the occurrence of Coccidia-like organisms in different diseases of man. In some of the cases the parasites proved to be fungi. This was the case with the parasites of a severe skin disease of man, formerly called Coccidioides immitis and Coccidioides pyogenes. Other statements are founded on misapprehensions, or are still much disputed. If reference is here made to “Eimeria hominis,” R. Blanchard, 1895, this is done on the authority of the investigator mentioned. The structures in question are nucleated spindle-shaped bodies of very different lengths (18 µ to 100 µ), which either occurred isolated or were enclosed in large globular or oval cysts, alone or with a larger tuberculated body (“residual body”). These formations were found by J. Künstler and A. Pitres in the pleural exudation removed from a man by tapping. The man was employed on the ships plying between Bordeaux and the Senegal River.
Blanchard looks upon the fusiform bodies as merozoites and the cysts as schizonts of a Coccidium. On the other hand, Moniez declares the spindle bodies to be the ova and the supposed residual bodies to be “floating ovaries” of an Echinorhynchus.
Severi’s “monocystid Gregarines,” which were taken from the lung tissue of a still-born child, are also quite problematical.
No less doubtful are the bodies which Perroncito calls Coccidium jalinum, and which he found in severe diseases of the intestine in human beings, pigs, and guinea-pigs; Borini also reported another case.