Hymenolepiasis

Hymenolepiasis is infestation by one of two species of tapeworm: Hymenolepis nana or H. diminuta.

Hymenolepis nana tapeworms

Other names

Dwarf tapeworm infection and rat tapeworm infection. The disease is a type of helminthiasis which is classified as a neglected tropical disease.

Symptoms

• Hymenolepiasis does not always have symptoms, but they usually are described as abdominal pain, loss of appetite, itching around the anus, irritability, and diarrhea. Hymenolepis infection or infection with the dwarf tapeworm is found worldwide. It is most often seen in children in countries in which sanitation and hygiene are inadequate. Although the dwarf tapeworm infection rarely causes symptoms, it can be misdiagnosed for pinworm infection.

Transmission

• One becomes infected by accidentally ingesting dwarf tapeworm eggs.
• This can happen by ingesting fecally contaminated foods or water, by touching your mouth with contaminated fingers, or by ingesting contaminated soil.
• People can also become infected if they accidentally ingest an infected arthropod (intermediate host, such as a small beetle or mealworm) that has gotten into food.
• Adult dwarf tapeworms are very small in comparison with other tapeworms and may reach 15-40 mm (up to 2 inches) in length. The adult dwarf tapeworm is made up of many small segments, called proglottids As the dwarf tapeworm matures inside the intestine, these segments break off and pass into the stool.
• An adult dwarf tapeworm can live for 4-6 weeks. However, once you are infected, the dwarf tapeworm may reproduce inside the body (autoinfection) and continue the infection.

Signs and symptoms

• Most people who are infected do not have any symptoms.
• Those who have symptoms may experience nausea, weakness, loss of appetite, diarrhea, and abdominal pain.
• Young children, especially those with a heavy infection, may develop a headache, itchy bottom, or have difficulty sleeping. Sometimes infection is misdiagnosed as a pinworm infection.
• Contrary to popular belief, a dwarf tapeworm infection does not generally cause weight loss.
• You cannot feel the dwarf tapeworm inside your body.

Diagnosis

• Diagnosis is made by identifying dwarf tapeworm eggs in stool.
• Your health care provider will ask you to submit stool specimens collected over several days to see if you are infected.

Treatment

• Treatment is available. A prescription drug called praziquantel is given.
• The medication causes the dwarf tapeworm to dissolve within the intestine.
• Praziquantel is generally well tolerated. Sometimes more than one treatment is necessary.

Spread to family members

Eggs are infectious (meaning they can re-infect you or infect others) immediately after being shed in feces.

Prevention

Wash your hands with soap and warm water after using the toilet, changing diapers, and before preparing foods.

Teach children the importance of washing hands to prevent infection.

When traveling in countries where food is likely to be contaminated, wash, peel or cook all raw vegetables and fruits with safe water before eating.