Contagious pustular dermatitis (CPD, contagious ecthyma, Orf) is a highly contagious viral disease afflicting sheep and goats. The infectious agent is a parapoxvirus which is widespread and also contagious for humans (zoonosis). Recently the disease in sheep and goats is marked by increased incidence and severe cases which cause many losses especially among lambs in fattening farms. The immunity of once infected animals is based on cellular defense mechanisms which are very unstable. The most suitable method for the prevention of ecthyma is parenteral vaccination with attenuated live vaccines. Effective vaccination programmes should enclose the whole animal population at intervals of 6-8 months.