Echinococcus

Causes and Risks:
The disease is common in southern South America, the Mediterranean, the Middle East, central Asia, and Africa. In the U.S., the disease has been reported in the lower Mississippi valley, Alaska, and northwestern Canada. Humans become infected when they swallow eggs passed in dog feces. The infection is carried to the liver where cysts form. Some cysts form in the lung. Infrequently cysts form in the brain, bones, skeletal muscles, kidney, spleen, or other tissues. A liver cyst may produce no symptoms for 10 to 20 years until it is large enough to be felt by physical examination or to produce symptoms. Risk factors include exposure to cattle, sheep, pigs, deer, or exposure to the feces of dogs, wolves, or coyotes. The incidence is 1 out of 100,000 people.

Prevention:
In endemic areas, health education and routine worming of dogs to remove tapeworms help prevent the disease.

Symptoms:



Signs and Tests:
A physical examination may reveal bony enlargement of joints.

Tests to determine the presence and location of the cysts are:



Treatment:
The definitive treatment is to remove the cysts surgically if the location of the cysts and the patient's condition permit the procedure. Treatment with chemotherapy is an alternative for inoperable cysts.

Prognosis:
The probable outcome is good for people with surgically removed cysts but less favorable when secondary cysts develop.

Complications:
Medications may produce side effects.

Call Your Healthcare Provider:
Call for an appointment with your health care provider if symptoms of this disorder develop.


This upper abdominal CT scan shows multiple cysts in the liver, caused by dog tapeworm (echinococcus). Note the large circular cyst (seen on the left side of the screen) and multiple smaller cysts throughout the liver.