Location: Animal Parasitic Diseases LaboratoryTitle: Gametogony of Cystoisospora canis and its distinction from meronts in the intestines of dogs
|LINDSAY, DAVID - Virginia-Maryland Regional College Of Veterinary Medicine (VMRCVM)|
Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2018
Publication Date: 4/25/2019
Citation: Dubey, J.P., Lindsay, D. 2019. Gametogony of Cystoisospora canis and its distinction from meronts in the intestines of dogs. Journal of Parasitology. 105(2)345-350. https://doi.org/10.1645/18-200
Interpretive Summary: Toxoplasma, Neospora, Sarcocystis, and Cystoisopora are related coccidian parasites that cause severe illness in livestock and companion animals. Oocyst is the environmentally resistant stage passed in feces of the definitive hosts. While Toxoplasma and Neospora have wide host range, Cystoisospora are more host specific. Cystoisospora canis is a pathogenic coccidian of dogs with many aberrant/paratenic hosts. Its life cycle is not fully known. Here, authors describe sexual cycle of C. canis using archived specimens; no new experiments were performed in dogs. These results will be of interest to parasitologists and veterinarians in diagnosis of coccidiosis in dogs.
Technical Abstract: The coccidian parasite Cystoisospora canis (syn. Isospora canis) can cause clinical disease in dogs. Three generation of schizonts have been reported previously in the small intestine of dogs before gametogony and oocyst excretion 9-11 days post inoculation (PI). Recently, we re-evaluated asexual development of C. canis in 2 dogs necropsied 10 days after oral inoculation with 100,000 C. canis oocysts; both dogs had excreted oocysts 9 days PI. Asexual and sexual stages were seen in the lamina propria, throughout the small intestine in sections stained with hematoxylin and eosin (HE). In previously reported life cycle studies no distinction between the last asexual generation of meronts and early microgamonts was reported. Here, we report development of microgamonts and their distinction from asexual stages using periodic acid Schiff reaction counter stained with hematoxylin and eosin. Using this method, we demonstrated that PAS positive granules can be used to identify microgamonts and differentiate them from developing meront stages.