Abstract
The life-cycle of canine Isospora bigemina was studied in dogs, cattle, cats and mice. Under experimental conditions dogs served as both definitive and intermediate hosts. Unsporulated oocysts (11 × 12 μm) were shed in the faeces and sporulated outside the host within 12 h at 30–37 °C and 36 to 48 h at 23 °C. Sporulated oocysts measured 12 × 13 μm and contained 2 sporocysts which in turn contained 4 sporozoites. Sporocysts averaged 6 × 9 μm and sporozoites averaged 2 × 6 μm. Although no stages were found microscopically in tissues or in faeces of 23 dogs orally inoculated with sporulated oocysts, the oocysts were infectious because 5 of 14 dogs that ingested tissues of dogs fed oocysts, shed oocysts. Prepatent periods were 7 to 15 days; patency was 1–3 days. No dogs became ill. In the naturally infected dog and one experimentally infected dog, schizonts were found in epithelial cells, distal to the host cell nucleus at the tips of villi throughout the small intestine. Schizonts were 5–7 μm and contained 3–12 merozoites. In the naturally infected dog, gametes were found in the same location. Male gametocytes were 6–8 μm and contained 6–12 microgametes, and female gametes were 7–8 μm.Sporulated I. bigemina oocysts from a naturally infected dog were not infectious to cattle, cats or mice. Structurally identical oocysts were shed by 2 dogs after ingesting hearts and diaphragm from naturally infected cattle; these oocysts were also not infectious to cattle. Although dogs acted as both intermediate and definitive hosts under experimentation, this is not likely to occur in nature. A canine-bovine-canine cycle would appear to be the natural mode of infection but I. bigemina was not infectious to cattle under experimental conditions.
Publisher
Cambridge University Press (CUP)
Subject
Infectious Diseases,Animal Science and Zoology,Parasitology
Reference19 articles.
1. Note preliminaire sur quelques parasites;Stiles;Bulletin de la Société zoologique de France,1891
2. Thegnotobiotic dog;Griesemer;Laboratory Animal Care,1963
3. Coccidia of the Genus Isospora in Cats, Dogs and Man
4. Experimental Hammondia Hammondi Infection in Dogs
5. The pathology of coccidiosis in the dog;Lee;Journal of the American Veterinary Medical Association,1934
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