Scabby mouth

By Dr Nik Cronin, Forbes District Vet

We saw quite a few outbreaks of scabby mouth in sheep right across our region last year, and heard of many other verbal reports as well. Scabby mouth is a well known viral disease that causes pustules and scabs to develop, usually around the face and mouth of affected animals, but also on other non-woolled parts of the body like the legs and udder. The virus is reasonably prevalent on sheep properties in our district and persists in the environment for many years. It is also important to remember that it’s a zoonosis and so we can be affected by pustules and scabs ourselves!

Face lesions are not uncommon, and often seen in mild form in lambs at marking. The classic presentation in outbreak form is young sheep, often weaners grazing rough feed - thistles, burr or stubbles. These feeds cause abrasions, resulting in a break in the skin’s defences necessary for viral entry and infection. Moving the mob to a paddock where the feed is not abrasive should stop new infections occurring. Badly affected animals may be reluctant to eat and drink and suffer a setback, particularly unweaned lambs.

When scabby mouth occurs on the legs, it is known as ‘strawberry footrot’. The bacteria that causes ‘dermo’ can sometimes also be involved. Constant wetting and maceration of the lower limbs in the lush, wet spring was a big factor in the cases seen last year. This form of the disease also ranges in severity, but can get really nasty with severe swelling of affected limbs.

Scabby mouth is generally self-limiting, however for badly affected animals pain relief may be considered. In addition, antibiotics may increase the rate of healing where extensive sores are secondarily infected.

There is a vaccine available to protect against scabby mouth, however it does not provide lifelong immunity. It's a live vaccine given by ‘scratch’ to a protected skin area and works to induce immunity following infection with a mild, controlled form of the disease. It is not advised to use the vaccine on properties that do not have a history of infection.

If you have any questions about scabby mouth, or strawberry footrot, you can get in contact us by calling the Central West Local Land Services animal health team on 1300 795 299.