Echinococcosis

Epidemiology

Cystic echinococcosis is globally distributed in most pastoral and rangeland areas of the world, with highly endemic areas in the eastern part of the Mediterranean region, northern Africa, southern and eastern Europe, at the southern tip of South America, in Central Asia, Siberia and western China.

In regions where cystic echinococcosis is endemic, incidence rates in humans can exceed 50 per 100 000 person-years; prevalence levels as high as 5–10% may occur in parts of Argentina, Central Asia, China, East Africa and Peru. In livestock, the prevalence in slaughterhouses in hyperendemic areas of South America varies from 20% to 95% of slaughtered animals.

The highest prevalence occurs in rural areas where older animals are slaughtered. Depending on the infected species involved, livestock production losses attributable to cystic echinococcosis stem from liver condemnation, reduction in carcass weight, decrease in hide value, decrease of milk production, and reduced fertility. Current estimates suggest that cystic echinococcosis results in the loss of 1–3 million disability-adjusted life years (DALYs) annually. Annual costs associated with cystic echinococcosis are estimated to be US$ 3 billion for treating cases and of losses to the livestock industry.

Conversely, alveolar echinococcosis is restricted to the northern hemisphere, in particular to regions of China, the Russian Federation and countries in continental Europe and North America. Alveolar echinococcosis results in the loss of about 650 000 DALYs annually, with most of the disease burden concentrated in western China.