About Alveolar echinococcosis (AE)

Key points

  • Alveolar echinococcosis is a parasitic tapeworm infection found in foxes, coyotes, and dogs.
  • Cases in people are rare but can be fatal if left untreated.
  • Symptoms include tumors in the liver, lungs, brain, and other organs.

Symptoms

AE is caused by tumor-like or cyst-like tapeworm larvae growing in the body. AE usually involves the liver but can spread to other organs of the body. Because the cysts are slow-growing, infection with AE may not produce any symptoms for many years. Pain or discomfort in the upper abdominal region, weakness, and weight loss may occur as a result of the growing cysts. Symptoms may mimic those of liver cancer and cirrhosis of the liver.

How it spreads

People who accidentally swallow the eggs of the Echinococcus multilocularis tapeworm are at risk for infection. People at high risk include trappers, hunters, veterinarians, or others who have contact with wild foxes, or coyotes, or their stool, or household dogs and cats that have the opportunity to eat wild rodents infected with AE. Humans can be exposed to these eggs by "hand-to-mouth" transfer or contamination.

  • By directly ingesting food items contaminated with stool from foxes or coyotes. This might include grass, herbs, greens, or berries gathered from fields.
  • By petting or handling household dogs or cats infected with the Echinococcus multilocularis tapeworm. These pets may shed the tapeworm eggs in their stool, and their fur may be contaminated. Some dogs "scent roll" in foreign material (such as wild animal feces) and may become contaminated this way.

Prevention

If you live in an area where Echinococcus multilocularis is found in rodents and wild canines, take the following precautions to avoid infection:

  • Don't touch a fox, coyote, or other wild canine, dead or alive, unless you are wearing gloves. Hunters and trappers should use plastic gloves to avoid exposure.
  • Don't keep wild animals, especially wild canines, as pets or encourage them to come close to your home.
  • Don't allow your dogs and cats to wander freely or to capture and eat rodents.
  • If you think that your pet may have eaten rodents, consult your veterinarian about possible preventive treatments.
  • Wash your hands with soap and warm water after handling dogs or cats, and before handling food.
  • Teach children the importance of washing hands to prevent infection.
  • Do not collect or eat wild fruits or vegetables picked directly from the ground. All wild-picked foods should be washed carefully or cooked before eating.

Diagnosis

See your healthcare provider if you think you may have alveolar echinococcosis (AE). Diagnosis of AE can be made by a blood test that looks for the presence of antibodies to Echinococcus multilocularis.

Treatment

Surgery is the most common form of treatment for AE, although removal of the entire parasite mass is not always possible. After surgery, medication may be necessary to keep the cyst from growing back.