Echinococcus granulosus and cystic hydatid in people

People are in the intermediate host position in the life cycle. If people ingest viable E. granulosus eggs from carnivore feces, they can develop a unilocular hydatid cyst in various organs and tissues, in Canada primarily in the lungs. These hydatids may be associated with clinical signs. The incidence of this condition in people in Canada has declined significantly over the past fifty years, although cases are still diagnosed in northern residents (often as an incidental finding during thoracic imaging), and in immigrants from countries where the parasite is more common. A recent study of cystic hydatid disease in people in Canada reported 108 hospitalizations during the period 2001 to 2005 in which the disease was the primary or secondary diagnosis (the latter where the primary diagnosis was likely related to cystic hydatid disease).  In this study incidence increased with latitude, and the disease was significantly more common in women than in men.  Because of the selection criteria used for case inclusion, however, the results of this study are likely an underestimate of the incidence of cystic hydatid in Canada.  In other parts of the world, the risk to human health has resulted in the implementation of comprehensive control programs, often with notable success.

Additional information about Echinococcus granulosus  is available under Dogs.