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A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M.; 2013.

A.D.A.M. Medical Encyclopedia.

Echinococcus

Hydatidosis; Hydatid disease, Hydatid cyst disease

Last reviewed: August 1, 2012.

Echinococcus is an infection caused by the Echinococcus granulosus or Echinococcus multilocularis worm.

Causes, incidence, and risk factors

Echinococcus is common in:

  • Africa
  • Central Asia
  • Southern South America
  • The Mediterranean
  • The Middle East

In the United States, the disease is very rare. However, it has been reported in California, Arizona, New Mexico, and Utah.

Humans become infected when they swallow eggs in contaminated food. The infection is carried to the liver, where cysts form. Cysts can also form in the:

Risk factors include being exposed to:

  • Cattle
  • Deer
  • Feces of dogs, wolves, or coyotes
  • Pigs
  • Sheep

Symptoms

A liver cyst may produce no symptoms for 10 - 20 years until it is large enough to be felt by physical examination.

Symptoms include:

Signs and tests

A physical examination may show signs of:

  • Abdominal pain
  • Problems with the skin and other organs

The following tests may be done to find the cysts:

Most often, echinococcosis is found when an imaging test is done for another reason.

Treatment

Many patients can be treated with albendazole or mebendazole. These medications are often used for up to 3 months. Another drug, praziquantel, may be helpful combined with albendazole or mebendazole.

The cysts may be removed with surgery, if possible. This can be a complicated surgery.

Expectations (prognosis)

If the cysts respond to oral medication, the likely outcome is good.

Complications

The cysts may break open (rupture) and cause severe illness, including:

The cysts may also spread throughout the body.

Calling your health care provider

Call your health care provider if you develop symptoms of this disorder.

Prevention

In areas where the disease is known to occur, health education and routinely removing tapeworms from dogs can help prevent the disease.

References

  1. King CH, Fairley JK. Cestodes (Tapeworms).In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 29.

Review Date: 8/1/2012.

Reviewed by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.

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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 endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

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 endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

Figures

  • Liver echinococcus - CT scan.
    Antibodies.

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