• Definition

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

    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