infectious diseases
Echinococcosis
Introduction
Echinococcosis is infection with larvae of the tapewormEchinococcus granulosus(cystic echinococcosis, hydatid disease) orEchinococcus multilocularis(alveolar disease). Symptoms depend on the organ involved—eg, jaundice and abdominal discomfort with liver cysts or cough, chest pain, and hemoptysis with lung cysts. Cyst rupture can cause fever, urticaria, and serious anaphylactic reactions. Diagnosis is with imaging, examination of cyst fluid, or serologic tests. Treatment is withalbendazole, surgery, or both or with cyst aspiration and instillation of a scolicidal agent. Echinococcus granulosusis common in sheep-raising areas of the Mediterranean, Middle East, Australia, New Zealand, South Africa, and South America. Foci also exist in regions of Canada, Alaska, and California. Dogs are the definitive hosts, which may have adult tapeworms in their gastrointestinal tract, and herbivores (eg, sheep, goats, swine, cattle, camels, horses, deer) or humans are intermediate hosts that develop cystic lesions in the liver or other organs. AdultE. multilocularisworms are present in foxes, coyotes, and dogs, and the hydatid larvae occur in small wild rodents. Infected dogs are the primary link to occasional human infection.E. multilocularisoccurs mainly in Central Europe, Alaska, Canada, and Siberia. Its range of natural infection in the continental United States extends from Wyoming and the Dakotas to the upper Midwest. Rarely,Echinococcus vogeliiorEchinococcus oliganthuscauses hydatid disease in humans, primarily in the liver. The disease may be polycystic (E. vogelii) or unicystic (E. oliganthus). These species occur in Central and South America. 