dwarf tapeworm infection, a type of intestinal parasitic disease caused by an infestation of Hymenolepis nana. It occurs mainly in the southern United States and usually affects children who ingest eggs by placing contaminated materials into the mouth. It is the most common tapeworm infection diagnosed in the United States and throughout the world. The disease may be asymptomatic or may result in abdominal complaints and diarrhea. An infection may be treated with niclosamide or paromomycin. Prevention involves good hygiene practices. It is often seen in children subject to institutional living. See also Hymenolepis.