Dog tapeworm cysticercoid stage (Taenia pisiformis)
Copyright 2003 Dennis Kunkel Microscopy, Inc.
Caption: Dog tapeworm cysticercoid stage (Taenia pisiformis) found in peritoneal cavity of an intermediate rabbit host. The tapeworm larvae develop into the cysticercoid stage in the host rabbit liver and intestinal tissue with the scolex being inverted into a fluid filled bladder. Tapeworms have no specialized digestive system but feed on the partially digested food in the intestines by direct absorption through their entire skin surface. In humans Taenia saginata tapeworms can cause diarrhea, weight loss and abdominal discomfort. Adult tapeworms may grow 5-10 meters in length. Life cycle: -Gravid proglottids are passed in dog feces. -Rabbits ingest eggs which are released from proglottids. -Hexacanth embryos hatch, penetrate the intestinal wall and arrive in the liver. -After developing in the liver 15-30 days, immature cysticerci penetrate thru the liver parenchyma. -Mature cysticerci are found in the peritoneal cavity, loosely attached to the viscera or mesenteries. -Canids are infected by eating cysticerci in rabbit viscera. -After ingestion the cysticerci evaginate and the scolex attaches to the mucosa of the small intestine to begin development of proglottids. Magnification*: x8 Type: SEM
*(Magnifications are based on a 35mm slide image of 24mm in the narrow dimension.)