Dipylidiasis is a common tapeworm infection of dogs and cats caused by Dipylidium caninum. Humans become infected by accidental ingestion of dog or cat fleas that contain D caninum cysticercoids (larva). The risk of infection to humans is low. These fleas and lice are the intermediate host for D caninum.
Dipylidiasis in humans occurs through accidental ingestion of the dog or cat flea or the dog louse infected with cysticercoids (the larval form of D caninum). These fleas and lice are the intermediate host for D caninum. Cysticercoids develop into adult worms in the small intestine of the host in about 20 days. The adult worm may attain a length of 10-70 cm and is 2-3 mm in diameter. The worms have a lifespan of less than 1 year.
Dipylidiasis is distributed worldwide, and human infection has been reported in Africa, Argentina, Australia, Chile, China, Europe, Guatemala, India, Japan, and the Philippines. Dipylidiasis does not appear to have a racial predilection. Dipylidiasis is most common in infants and in children younger than 8 years. The adult tapeworm develops in about 20 days; however, since most infections are asymptomatic, although some children with dipylidiasis may have intestinal disturbances. Symptoms that appear include abdominal pain with or without diarrhea, loss of appetite, allergic manifestations (eg, pruritus, rash) may occur, increased irritability, intestinal obstruction is a rare complication of dipylidiasis.
The anthelmintic agents praziquantel and niclosamide are the preferred drugs for treatment of dipylidiasis. Ivermectin has no effect on D caninum. The goals of pharmacotherapy are to reduce morbidity, to prevent complications, and to eradicate infection. The patient's stool should be examined for eggs and proglottids of D caninum at 1 and 3 months after treatment to ensure cure.