Taenia hydatigena

Taenia hydatigena (thin-necked bladderworm, causative agent of cysticercosis) is one of the adult forms of the canine and feline tapeworm. This infection has a worldwide geographic distribution. Humans with taeniasis can infect other humans or animal intermediate hosts by eggs and gravid proglottids passed in the feces. T. solium eggs can cause cysticercosis in humans. Intermediate hosts, which harbor the disease for a short period of time, include: sheep, horses, cattle, pigs, and deer. Definitive hosts, which harbor the parasite until it reaches maturity and during sexual reproduction, include dogs, foxes, and other canids. The cysticercus, the larval form, travels and persists in the liver for 18 – 30 days, then burrows out into the peritoneal cavity and attaches to the viscera. When the sheep viscera is scavenged and the scavenger ingests the cysticercus, the protoscolex attaches to the small intestinal wall and the worm begins to form proglottids. Gravid proglottids, containing the eggs, move from the end of the worm and leave the body in the feces. The prepatent period is about 51 days.