Health Encyclopedia

Tapeworm infection - hymenolepis

Definition

Hymenolepis infection is an infestation by one of two species of tapeworm: Hymenolepis nana or Hymenolepis diminuta. The disease is also called hymenolepiasis.

Alternative Names

Hymenolepiasis; Dwarf tapeworm infection; Rat tapeworm; Tapeworm - infection

Causes

Hymenolepis worms live in warm climates and are common in the southern United States. Insects eat the eggs of these worms.

Humans and other animals become infected when they eat material contaminated by insects (including fleas associated with rats). In an infected person, it is possible for the worm's entire life cycle to be completed in the bowel, so infection can last for years.

Hymenolepis nana infections are much more common than Hymenolepis diminuta infections in humans. These infections used to be common in the southeastern United States, in crowded environments, and in people who were confined to institutions. However, the disease occurs throughout the world.

Symptoms

Symptoms occur only with heavy infections. Symptoms include:

Diarrhea
Gastrointestinal discomfort
Itchy anus
Poor appetite
Weakness

Exams and Tests

A stool exam for the tapeworm and its eggs confirms the diagnosis.

Treatment

The treatment for this condition is a single dose of praziquantel, repeated in 10 days.

Household members may also need to be screened and treated because the infection can be spread easily from person to person.

Outlook (Prognosis)

Expect full recovery following treatment.

Possible Complications

Health problems that may result from this infection include:

Abdominal discomfort
Dehydration from prolonged diarrhea

When to Contact a Medical Professional

Contact your health care provider if you have chronic diarrhea or abdominal cramping.

Prevention

Good hygiene, public health and sanitation programs, and elimination of rats help prevent the spread of hymenolepiasis.

References

Alroy KA, Gilman RH. Tapeworm infections. In: Ryan ET, Hill DR, Solomon T, Aronson NE, Endy TP, eds. Hunter's Tropical Medicine and Emerging Infectious Disease. 10th ed. Philadelphia, PA: Elsevier; 2020:chap 130.

White AC, Brunetti E. Cestodes. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 325.

Review Date:8/26/2023
Reviewed By:Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.