Intestinal tapeworm infestation frequently occurs without symptoms; occasionally there is abdominal discomfort, diarrhea, constipation, or weight loss. The presence of tapeworm proglottids in clothing, bedding, or feces is the usual sign of infestation. Treatment is with quinacrine hydrochloride (Atabrine) or niclosamide, which kill the worm.
The most serious tapeworm infestation in humans is caused by the ingestion of T. solium eggs through fecal contamination, which results in the person serving as the intermediate, rather than the primary, host. The embryos migrate throughout the body, producing serious illness if they lodge in the central nervous system. In many poorer regions of the world, the larvae of T. solium are a major cause of human epilepsy. The embryos of the dog tapeworm encyst in various internal organs of humans, most commonly in the liver. The cysts produced by these embryos are called hydatid cysts, and the infestation of the liver is called hydatid disease.