Who is at risk for alveolar echinococcosis (AE)?

People who accidentally swallow the eggs of the Echinococcus multilocularis tapeworm are at risk for infection. Humans can be exposed to these eggs in two main ways that involve "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.

Where is alveolar echinococcosis (AE) found?

AE is found worldwide, mostly in northern latitudes. Cases have been reported in central Europe, Russia, China, Central Asia, Japan, and North America. In North America Echinococcus multilocularis is found primarily in the north central region from eastern Montana to central Ohio, as well as Alaska and Canada. Human cases have been reported in Alaska, the province of Manitoba, and Minnesota. Prevalence among wild foxes and coyotes is high, and may reach over 50% in some areas; however, even in these areas, transmission to humans has been low.

How is alveolar echinococcosis (AE) spread?

For 50 years, Echinococcus multilocularis was thought to be confined to the Alaskan coast and Canada. Now, because wild coyotes, foxes, and wolves are being trapped and transported to states where Echinococcus multilocularis has not previously been found, there is increased risk of spreading the disease to animals and humans. Wild animals carrying the tapeworm could set up the transmission cycle and expose animals not already infected. Many states prohibit this movement of wild animals, but trapping and movement of infected wild canines still occurs. If the transportation and relocation of these animals continues, the risk of human transmission will increase. Although the chances of contracting AE are low, certain groups may be at greater risk.

You may be at greater risk if you live in an area where Echinococcus multilocularis is found. People at high risk include trappers, hunters, veterinarians, or others who have contact with wild foxes, coyotes, or their stool, or household dogs and cats that have the opportunity to eat wild rodents infected with AE.

What are the symptoms of alveolar echinococcosis (AE)?

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 do I know if I have alveolar echinococcosis (AE)?

See your health care provider if you think you may have been exposed to the parasite by one of the ways described above. Diagnosis of AE can be made by a blood test that looks for the presence of antibodies to Echinococcus multilocularis.

How is alveolar echinococcosis (AE) treated?

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.

Can alveolar echinococcosis (AE) be prevented?

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 the possible need for 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.

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This information is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the disease described above or think that you may have a parasitic infection, consult a health care provider.