Typical lesions include papules, pustules, and scabs covering ulceration, granulation and inflammation. Lambs cannot suck or graze. The malignant form occurs with invasion of alimentary tract and severe systemic reaction. Lesions can be chronic and the virus withstands drying and is capable of surviving at room temperature for at least 15 years . Transmission is by direct contact with infected animals and as a result most human cases occur in people working with infected sheep and abattoir workers especially those handling wool and skins.
Typical lesions occur at an area of skin abrasion or by accidental means when vaccinating.
Lesions are similar to those seen in animals including scabs, pustules, granulation tissue and secondary lesions. The lesions are very itchy and respond poorly to local treatment. No specific treatment is available, but it is important to care for the lesions and prevent secondary infections. Lambs with oral lesions require feeding with soft, palatable food until lesions are gone from the muzzle and oral cavity. Affected animals can be isolated from susceptible animals and handled with care.