This contagious disease of sheep is caused by a virus. Lesions of the prepuce, penis, and vulva occur as a result of transmission by breeding. In early stages of infection in rams, a small lesion on the prepuce may be the only visible lesion, so it is difficult to differentiate from sheath rot. As the condition spreads, the penis becomes infected and the ram may be unable to breed because of swelling and secondary infection. To minimize disease transmission, remove infected animals from the flock and do not return them until they are completely recovered. Recoveries with or without treatment normally require two to eight weeks. Treatment is of value if secondary infection occurs or if severe ulcerations interfere with the animal's ability to eat or walk. The scab may be removed from the ulceration and copper sulfate solution or other antiseptics applied.