Cystic Echinococcosis (CE) FAQs
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How do people get cystic echinococcosis (CE)?
People who accidentally swallow the eggs of the Echinococcus granulosus tapeworm are at risk for infection. Dogs that eat home-slaughtered sheep and other livestock become infected with the tapeworm Echinococcus granulosus and the tapeworm eggs can be found in their stool. Direct contact with infected dogs, particularly intimate contact between children and their pet dogs, may lead to human infection. Ingestion of soil, water and vegetables contaminated with infected dog feces may also lead to infections. Echinococcus granulosus eggs can survive snow and freezing conditions.
Humans can be exposed to these eggs by "hand-to-mouth" transfer or contamination.
- By ingesting food, water or soil contaminated with stool from infected dogs. This might include grass, herbs, greens, or berries gathered from fields.
- By petting or handling dogs infected with the Echinococcus granulosus tapeworm. These dogs may shed the tapeworm eggs in their stool, and their fur may be contaminated.
Where is cystic echinococcosis (CE) found?
CE is found in Africa, Europe, Asia, the Middle East, and Central and South America. Highest prevalence is found in populations that raise sheep. In North America, Echinococcus granulosus is rarely reported in Canada and Alaska, and a few human cases have also been reported in Arizona and New Mexico in sheep-raising areas. In the United States, most infections are diagnosed in immigrants from counties where CE is endemic. Risk factors for human infection include uncontrolled dogs living closely with people, uncontrolled slaughter of livestock, and unsanitary living conditions.
What are the symptoms of cystic echinococcosis (CE)?
CE is caused by cyst-like tapeworm larvae growing in the body. CE usually involves the liver or the lungs, but can also be found in other organs of the body. Because the cysts are slow-growing, infection with CE may not produce any symptoms for many years. Pain or discomfort in the upper abdominal region or chest, nausea, vomiting, or coughing may occur as a result of the growing cysts. Rupture of cyst fluid can lead to allergic reactions or even death.
What should I do if I think I have cystic echinococcosis (CE)?
See your health care provider if you think you may have cystic echinococcosis. CE can be diagnosed with imaging studies such as X-rays or MRI scans, which are helpful to see the cysts in most organs. Blood tests are available to help diagnose an infection, but may not always be accurate. If surgery is necessary, confirmation of the diagnosis can be made by the laboratory.
How is cystic echinococcosis (CE) treated?
Until recently, surgery was the only option for treatment of CE. However, now medication and a modified surgical procedure (aspiration) are increasingly used and can replace the need for surgical removal of the hydatid cysts. Even so, surgery may be necessary in certain circumstances. After surgery, medication may be needed to keep the cyst from growing back.
Can cystic echinococcosis (CE) be prevented?
If you live in an area where Echinococcus granulosus is found in sheep or cattle, take the following precautions to avoid infection:
- Wash your hands with soap and warm water after handling dogs, and before handling food.
- Teach children the importance of washing hands to prevent infection.
- Avoid ingestion of food, water or soil contaminated with stool from dogs. This might include grass, herbs, greens, or berries gathered from fields.
- Don't allow your dogs to wander freely or to capture and eat raw meat from sheep, cattle, pigs, and goats.
- Don't home slaughter sheep and other livestock.
- If you think your pet may have eaten infected meat, consult your veterinarian about the possible need for preventive treatments.
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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 parasites described above or think that you may have a parasitic infection, consult a health care provider.