Mange in Sheep and Goats

Sarcoptes scabiei var ovis infests sheep, and S scabiei var caprae infests goats, throughout the world. However, S scabiei var ovis is rare in the USA. This mite infests nonwooly skin, usually on the head and face. Typical of scabies, lesions manifest with formation of crusts and intense pruritus. Affected animals have decreased reproduction, meat gain, and milk yield. In goats, S scabiei var caprae is responsible for a generalized skin condition characterized by marked hyperkeratosis. Lesions start usually on the head and neck and can extend to the inner thighs, hocks, brisket, ventral abdomen, and axillary region. Both S scabiei var ovis and S scabiei var caprae are zoonotic. Consistent with other animal variants of Sarcoptes, zoonoses are initiated from direct contact with infested animals but are self-limiting infestations.

Chorioptes bovis infests sheep and goats worldwide. Prevalence of C bovis is more common in rams than ewes or lambs. Infestation of C bovis on goats is fairly common, with most of a herd infested. Distribution of lesions is the same as that in cattle, with papules and crusts seen on the feet and legs. Most sheep are subclinically infested with C bovis. However, C bovis can cause exudative dermatitis on the lower legs and scrota of rams (scrotal mange). Semen quality may be affected, presumably due to increased temperature of infested scrota.

Psoroptes ovis is a highly contagious and severe infestation of sheep. This mite has been eradicated from sheep in Canada, New Zealand, and the USA. However, sheep scab persists in many countries, including some in Europe. Intense pruritus leads to large, scaly, crusted lesions that develop in more densely haired or woolly parts of the body. Lesions begin on the back and side but may become generalized and cover a large portion of the body. Animals bite, lick, and scratch in response to the pruritus, which results in wool loss and secondary bacterial infection. If affected sheep are not treated, infested animals may become emaciated and anemic and possibly die.

Psoroptic mange (ear mange) in goats and sheep is caused by P cuniculi, which is likely a variant of P ovis. P cuniculi typically infests the ears of goats but can spread to the head, neck, and body. Infestation of P cuniculi in goats can be common, with 80%–90% of a herd infested. Disease can range from subclinical to scaling, crusting, inflammation, alopecia, ear scratching, head shaking, and rubbing of ears and head to alleviate irritation. Although the course is chronic, the prognosis is good with appropriate treatment.

Demodex ovis infests sheep, and D caprae infests goats. Demodectic mange in sheep is not common, whereas D caprae are relatively common in goats. Lesions are similar to those in cattle. In goats, nonpruritic papules and nodules develop, especially over the face, neck, shoulders, and sides or udder. Demodectic mange in goats occurs most commonly in kids, pregnant does, and dairy goats. The nodules contain a thick, waxy, grayish material that can be easily expressed; mites can be found in this exudate. The disease can become chronic. Historically, in some cases, localized lesions in goats have been managed by incision, expression, and infusion with Lugol’s iodine or rotenone in alcohol (1:3). This practice should not be continued or condoned. Rotenone, a plant-derived ketone once a popular pesticide and ectoparasiticide approved for use in organic farming, is now available only as a piscicide in the USA and Canada.

Psorobia ovis (formerly Psorergates ovis) is a common skin mite of sheep in Africa, Australia, New Zealand, and South America. Most infested sheep are not affected. However, intense generalized pruritus and scaliness, with matting and loss of wool can result from infestation with P ovis. All breeds of domestic sheep are susceptible. Because of their small size, the mites are difficult to find in skin scrapings. This disease can cause significant economic losses through weight loss and wool damage. Treatments effective against sarcoptic, chorioptic, and psoroptic mange in sheep are expected to be efficacious for psorergatic mange.