Dwarf tapeworm infection, also known as Hymenolepis nana infection, is the world’s most prevalent cestode parasite. H. nana is more common in regions with warmer climates, such as South Europe, the United States, Russia, India, and Latin America. Infection is most prevalent among youngsters, those who reside in institutions and crowded surroundings, and those who reside in regions with poor hygiene and sanitation. In dry, warm locations of poor countries, infection is most frequent among children aged 4–10 years.
People can become infected by unknowingly consuming dwarf tapeworm eggs, ingesting polluted food or water, or by touching mouth parts with infected fingers. Humans can also get infected by unintentionally ingesting an infected arthropod that has gotten into their food. It is possible for the worm’s full life cycle to be completed in the intestines of an infected individual; therefore, the illness may linger for years.