Dipylidium is tapeworm of cats and dogs. People become infected when they accidentally swallow a flea infected with tapeworm larvae; most reported cases involve children. Dipylidium infection is easily treated in humans and animals.
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.
United States: A few cases of dipylidiasis have been reported in the United States, but the exact incidence is not known. International: Dipylidiasis is distributed worldwide, and human infection has been reported in Africa, Argentina, Australia, Chile, China, Europe, Guatemala, India, Japan, and the Philippines. Race: Dipylidiasis does not appear to have a racial predilection. Sex: Males and females are equally susceptible to dipylidiasis. Age: Dipylidiasis is most common in infants and in children younger than 8 years. Dipylidiasis has been reported in a 5-week-old infant.