Cystoisospora suis

Cystoisospora suis is an apicomplexan coccidian parasite that infects suckling piglets, causing neonatal porcine cystoisosporosis (also known as porcine coccidiosis), characterized by non-hemorrhagic diarrhea, mucosal damage in the small intestine, poor weight gain, and disrupted gut microbiome establishment. The parasite's direct life cycle occurs entirely within the pig host: sporulated oocysts are ingested, excyst, and release sporozoites that invade enterocytes, undergoing asexual merogony (multiple types peaking at 4-5 days post-infection) followed by sexual gamogony, leading to unsporulated oocysts excreted in feces that sporulate externally within days. Neonates are highly susceptible due to immature immune responses, while older pigs develop age-related resistance; extraintestinal stages in tissues like spleen, lymph nodes, and liver may enable persistence, though not fully confirmed. In disease, it destroys villous epithelium, promotes secondary bacterial invasions (e.g., E. coli), and results in high litter morbidity but low mortality. Toltrazuril is used for treatment, and genomic studies (~84 Mb, >8000 genes) suggest potential for new anticoccidials targeting kinases or parasite-specific pathways, given its relation to Toxoplasma and Neospora.

Other names

Isospora suis

null (no specific mechanisms detailed for drugs; toltrazuril treatment noted in infection studies)