Life Cycle of Cystoisospora felis (Coccidia: Apicomplexa) in Cats and Mice

Abstract

Cystoisospora felis is a ubiquitous apicomplexan protozoon of cats. The endogenous development of C. felis was studied in cats after feeding them infected mice. For this, five newborn cats were killed at 24, 48, 72, 96, and 120 h after having been fed mesenteric lymph nodes and spleens of mice that were inoculated with C. felis sporulated sporocysts. Asexual and sexual development occurred in enterocytes throughout the villi of the small intestine. The number of asexual generations was not determined with certainty, but there were different sized merozoites. At 24 h, merogony was seen only in the duodenum and the jejunum. Beginning at 48 h, the entire small intestine was parasitized. At 24 h, meronts contained 1-4 zoites, and at 48 h up to 12 zoites. Beginning with 72 h, the ileum was more heavily parasitized than the jejunum. At 96 and 120 h, meronts contained many zoites in various stages of development; some divided by endodyogeny. The multiplication was asynchronous, thus both immature multinucleated meronts and mature merozoites were seen in the same parasitophorous vacuole. Gametogony occurred between 96 and 120 h, and oocysts were present at 120 h. For the study of the development of C. felis in murine tissues, mice were killed from day 1 to 720 d after having been fed 10(5) sporocysts, and their tissues were examined for the parasites microscopically, and by bioassay in cats. The following conclusions were drawn. (1) Cystoisospora felis most frequently invaded the mesenteric lymph nodes of mice and remained there for at least 23 mo. (2) It also invaded the spleen, liver, brain, lung, and skeletal muscle of mice, but division was not seen based on microscopical examination. (3) This species could not be passed from mouse to mouse.

Experimental transmission of Cystoisospora felis-like coccidium from bobcat (Lynx rufus) to the domestic cat (Felis catus)

“…Others have indicated that developmental stages of C. felis are in the enterocytes of the small intestine and above the host cell nucleus (Hitchcock, 1955;Shah, 1971;Dubey, 2014). Additionally, the bobcat C. felis-like had an 87% identity to domestic cat C. felis isolate AEH CF14 (KP411388) published in GenBank.…”

Occurrence and genetic diversity of piroplasms and other apicomplexa in wild carnivores

“…Cystoisospora spp. are ubiquitous intestinal protists of wild and domestic carnivores that can also invade extra-intestinal organs such as spleen of definitive and paratenic host (Dubey, 2014). Badgers are commonly infected with Cystoisospora melis (Pellérdy, 1955), however, sequences of this coccidium are not available and published records are based on the morphology of oocysts isolated from badgers’ fecal samples (Anwar et al 2000).…”

Re-evaluation of merogony of aCystoisospora ohioensis-like coccidian and its distinction from gametogony in the intestine of a naturally infected dog

“…The undivided mass was considered multinucleated meront and not a residual body. This is normal pattern in asexual stages of cat and dog coccidia (Dubey, 2018; Dubey and Lindsay, 2019 b , 2019 c ). However, ultrastructural studies are needed to resolve mode of multiplication of all canine Cystoisospora species.…”

“…Up to eight nuclei were seen in meronts in preparations stained with Giemsa but the mode of division was not clear and multinucleated round or oval-shaped meronts commonly seen in Eimeria species (Levine, 1973) were not detected. A review of literature and re-review of histological sections of enteric stages of C. felis , C. rivolta , C. canis , C. ohioensis , of dogs and cats revealed that there is lack of confirmation of schizony in their asexual stages (Dubey, 2018; Dubey and Lindsay, 2019 a , 2019 b ). Therefore, asexual stages were termed meronts.…”