Cysticercus pisiformis (larval form)

Etiology:  Taenia pisiformis is a cestode (tapeworm).

Incidence: Incidence of infection is rare in laboratory animals.

Transmission: Transmission occurs via ingestion of feed or bedding contaminated with dog fecal material.

Rabbits serve as the intermediate host for the canine tapeworm Taenia pisiformis. Rabbits ingest feed or bedding that has been contaminated with dog feces. The eggs develop into cysticerci (intermediate form) within the liver or peritoneal cavity. The life cycle is completed when the definitive host (dog) ingests an infected rabbit.

Distribution:  Taenia pisiformis is found in the liver and peritoneal cavity.

Clinical Signs:  Clinical signs are not usually observed.

Diagnosis:

Antemortem: Cysts may be palpable if numerous.

Postmortem: Cysts may be identified

Diagnostic Morphology:  A 10 – 18 mm cystic structure (bladder) containing straw-colored fluid is attached to liver, mesentery or viscera in the peritoneal cavity. Sometimes Taenia pisiformis is found free in the peritoneal cavity.