Echinococcus

• Alternative Names

  Hydatidosis; Hydatid disease, Hydatid cyst disease

• 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:

  • Brain
  • Bones
  • Kidney
  • Lungs
  • Skeletal muscles
  • Spleen

  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:

  • Pain in the upper right part of the abdomen
  • Bloody sputum
  • Chest pain
  • Cough
  • Fever
  • Severe skin itching
• Signs and tests

  A physical examination may show signs of:

  • Abdominal pain
  • Problems with the skin and other organs
  • Shock

  The following tests may be done to find the cysts:

  • Abdominal CT scan or ultrasound
  • Abdominal X-ray
  • Blood test
  • Chest x-ray
  • Liver function tests
  • Thoracic CT scan or ultrasound

  Most often, echinococcosis is found accidentally 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:

  • Fever
  • Low blood pressure
  • Shock

  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

  Craig PS, McManus DP, Lightowlers MW, Chabalgoity JA, Garcia HH, Gavidia CM, et al. Prevention and control of cystic echinococcosis. Lancet Infect Dis. 2007;7:385-394.

Review Date: 8/1/2008

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., Inc.