Differential diagnosis and treatment of sheep scab

CLINICAL sheep scab (Psoroptes ovis infestation) is a highly contagious ectoparasitic disease affecting sheep of all ages. The clinical signs include pruritus, serous exudation and eventually severe debilitation in untreated sheep. The failure to identify early lesions and/or improper treatment of sheep infested with P ovis, are real welfare concerns. Following the deregulation of the previous sheep scab control measures (Sheep Scab [National Dip] Order 1990) in July 1992, there has been an alarming increase in the number of outbreaks of sheep scab reported in the UK. There is now no statutory device to ensure that sheep are correctly plunge‐dipped for the control of P ovis infestation. Veterinary surgeons must, therefore, advise on the most appropriate treatment for each outbreak of sheep scab, depending on the severity of the infestation, the stage of pregnancy of the sheep and the handling facilities available.