Sheep scab: Tiny mites, huge impact

Sheep scab is not limited to a single flock or farm.

- Koos du Pisanie

It can spread rapidly and, if not controlled, quickly escalate into a serious outbreak. Because of its potential damage, sheep scab is classified as a notifiable disease. This means the National Department of Agriculture and provincial authorities may intervene if an outbreak occurs.

Dr Willie Harris, a veterinarian at Noord-Kaap Repro en Veeartsenydienste in Upington, explains that sheep scab is caused by the mite Psoroptes ovis, which lives on the skin of sheep and goats. Once an animal becomes infected, the mite population doubles every six days. Visible clinical signs usually appear after six to eight weeks, and within two to three months the disease can spread through an entire flock.

Certain areas in South Africa are considered hotspots where sheep scab occurs more frequently. The Eastern Cape is particularly affected, especially in communal farming regions. This is partly because many producers do not make use of dipping or prophylactic sprays.

According to Dr Harris, outbreaks also occur regularly in the Free State, often because cases are reported too late. In the Western Cape, areas such as Hopefield, Moorreesburg, Bredasdorp, and Beaufort West are also known for recurring outbreaks. One contributing factor is the introduction of animals that are already infected. Sheep scab occurs sporadically but not widespread in the Northern Cape.