Definition
Tapeworms are internal parasites that live in the small intestines of their definitive mammalian hosts, causing little serious harm to them other than possible enteritis, anal itchiness and ill thrift. In dogs, the primary tapeworm parasites are Taenia pisiformis, Dipylidium caninum, Echinococcus spp. and Mesocestoides.
How Tapeworms Affect Dogs
Dogs frequently are infected with tapeworms without showing any clinical signs. When symptoms do occur, they usually are nonspecific and include perianal pruritus, weight loss, poor coat quality, increased appetite with little weight gain, abdominal pain, diarrhea, lethargy and general irritability. Owners may notice tapeworm segments crawling around their dog’s anal area that resemble grains of white rice or sesame seeds. Affected animals may “scoot” their bottom along the ground from the itchiness and irritation often caused by tapeworms. Uncommonly, heavy loads of adult tapeworms may cause intestinal obstruction.
Causes of Tapeworm Infection
Dogs become infected with tapeworms by ingesting an intermediate host that contains tapeworm larvae or cysts. Taenia, Echinococcus and Mesocestoides typically are acquired by ingestion of the viscera of infected birds, reptiles, sheep, rabbits, rats or other rodents. Dipylidium is caused by ingestion of adult fleas containing tapeworm eggs.
Preventing Tapeworm Infection
Regular de-worming with veterinarian-recommended products is effective in preventing or eliminating tapeworm infection. Flea control is also important in preventing tapeworm infection. Good hygiene is essential to prevent human acquisition of tapeworms through fecal-oral contamination from infected dogs. People should avoid eating undercooked meat of potential intermediate host animals (sheep, cattle, rabbits).
Special Notes
The prognosis for dogs infected with tapeworms is excellent, as long as the owners follow the appropriate treatment protocol. Because of their indiscriminate oral experimentation, young children are at risk for Dipylidium tapeworm infection by ingestion of adult fleas. Humans are also at risk of developing highly pathogenic or even fatal hydatid disease if they ingest Echinococcus eggs either from the feces of definitive host animals (dog licking owner’s face) or from the cyst form in raw or undercooked meat from intermediate hosts such as cattle, rabbits or sheep.