Hydatid disease (Echinococcosis)

Hydatid disease is caused by infection with the larval stage of the dog tapeworm Echinococcus granulosus, acquired by ingestion of tapeworm eggs.

It is maintained via a sheep to dog cycle in which, occasionally, humans (rather than sheep) are infected by eggs excreted in the faeces of infected dogs.

In the United Kingdom, hydatid disease is found mainly in the sheep farming areas of Herefordshire, mid-Wales, and the Western Isles of Scotland. Mid-Wales had the highest incidence in the UK up until the mid-1980s when a scheme for compulsory free worming of dogs was introduced. This resulted in the disappearance of new cases in children under fifteen years of age. The scheme was discontinued in the early 1990s.