Hydatid disease is caused by a tapeworm that lives in the intestines of domestic dogs, foxes and
wolves. The disease often starts without symptoms and this may last for years. The symptoms and
signs that occur depend on the cyst’s location and size, but are commonly found in the liver or lungs.
The disease is spread when food or water that contains the parasite eggs are ingested or through
contact with feces of infected dogs.
How do dogs become infected?
Dogs that eat the internal organs of an animal that contains the cysts such as sheep or cattle can
become infected. In Chile, there are millions of sheep in the southern Patagonia region and this
disease exists at very high prevalence. Interestingly, dogs are not negatively affected by the
tapeworms. Sheep with internal cysts are rarely affected, but there are economic losses when the
animals are butchered. It is when people become infected, that serious problems occur.
Image courtesy of http://www.medindia.net/patients/patientinfo/hydatid-disease.htm
Treatment and Prevention
Prevention of the disease is by constant and consistent administration of dewormers to dogs, that treat this kind of
tapeworm and through vaccination of sheep. Diagnosis and treatment of disease is often difficult. People are
usually diagnosed using radiographs (x-rays), but because the cysts and symptoms take some time to
develop, the cysts can be very large when the person is actually diagnosed. The cysts have to be
removed through surgery and followed up with medication, sometimes the disease is fatal. Education is
key in prevention of human cases.
The disease occurs in most areas of the world and currently affects about one million people. In
some areas of South America, Africa, and Asia up to 10% of the certain populations are affected. In
2010, it caused about 1200 deaths down from 2000 in 1990. The economic cost of the disease is
estimated to be around 3 billion USD a year.