Life cycle of Isospora burrowsi n sp (Protozoa: Eimeriidae) from the dog Canis familiaris.
Exogenous and endogenous stages of Isospora burrowsi n sp from the dog are described. Oocysts were spherical or ellipisoidal and 17 to 22 by 16 to 19 micrometer (mean 20.3 by 17.3 micrometer). Micropyle, oocyst residuum, and polar granule were not present. Sporocysts were 12 to 16 by 8 to 11 micrometer (mean 14.4 by 9.7 micrometer). Stieda body was absent, but a sporocyst residuum was present. Endogenous stages were in the caudal three-fifths of the small intestine and in the cecum. Mature 1st-generation schizonts (11 to 18 by 9 to 18 micrometer) were present on the 4th day of infection. One day later, mature 2nd-generation schizonts (18 to 35 by 17 to 22 micrometer) were present. Immature gamonts were found 5 days after infection, and unsporulated oocysts were also present later that day. The prepatent period was 6 days, and the mean patent period was 11 days. The oocysts of I burrowsi differ markedly in size from all other Isospora species from dogs, except Isospora ohioensis; however, the endogenous stages of the 2 species differ.
D000818:Animals; D003048:Coccidiosis / Q000469:parasitology / Q000662:veterinary*; D004283:Dog Diseases / Q000469:parasitology*; D004285:Dogs; D007421:Intestine, Small / Q000469:parasitology; D007549:Isospora / Q000166:cytology / Q000254:growth & development*