(also contagious ecthyma or sore mouth), a virus disease of sheep and goats (cases have been reported in man).

In animals, the disease is characterized by the formation of vesicles, pustules (blister-like rash), and scabs primarily near the lips and, less commonly, on other parts of the body. The disease may occur at any time of the year, and when it does, it attacks almost all the livestock (especially the young animals). Injury to the skin promotes infection. Sick and convalescent animals are the sources of the causative agent. In most cases the disease is complicated by a secondary infection of a microbial nature. The sick animals eat with difficulty, and lameness is often observed. The diagnosis is based on epizootiological data, symptoms, and results of laboratory tests.