Psoroptic mange is caused by scab mites, Psoroptes ovis, and is a highly contagious skin disease of sheep. State and federal quarantines and treatment apparently have eradicated the mite; however, reduced vigilance in the detection of this pest may result in outbreaks of scabies anywhere in the United States. The mites, which live in colonies on the skin surface, cause the wool to fall off and the skin to become roughened and covered with a dried crust or scab. The mites pierce the skin with their mouthparts, and scabs form over the bites when blood and serum ooze from the wounds. The areas that are usually affected include the withers, back, sides, and rump. Infested animals bite and rub continuously. Sheep with serious infestations may gradually weaken and eventually die.
Positive diagnosis can be made only by scraping lesions on the sheep with a knife and observing the mites in the scrapings. The mite is small with a white or yellow body and brown legs. Because of federal and state quarantine and treatment regulations, a veterinarian should examine animals suspected of having scabies.
Because of federal and state quarantine and treatment regulations, a veterinarian should examine animals suspected of having scabies.