Scabby mouth (contagious pustular dermatitis) is a non-fatal but debilitating disease of sheep and goats. Highly contagious, it’s caused by a pox virus that usually infects lambs in the first year of life.
The virus is present in the scabs in affected animals, but it can also survive off the sheep for many years if environmental conditions are suitable – once introduced to a property, it tends to remain.
Impact on humans
Scabby mouth is a zoonoses – that means it can spread to humans! Always wear gloves and protective clothing to safeguard against inadvertent vaccine splash entering skin wounds.
Critical to the development of scabby mouth are injuries and abrasions on the bare skin around the lips (most common area) and other areas including the udder, scrotum and coronet. The virus enters through the broken skin and 2 to 4 days later the infected areas become red and swollen, quickly progressing to blisters, pustules, then ruptured lesions and scab formation.
While healing is quite fast after the scabs fall off – this takes 1 to 2 weeks – with lesions gone within 4 to 6 weeks, severely affected lambs will often be too sore to eat. Loss of condition is common. This can be compounded if the ewe develops lesions on her udder, the pain making her reluctant to allow suckling.
Treatment and control
There is no treatment for the scabby mouth virus apart from individual cases where antibiotics can combat secondary infection. Control is focused on minimising spread by avoiding the feeding of hay containing thistles or grazing on paddocks with burrs and thistles, and avoiding crowding in sheds – the virus will contaminate feed troughs, increasing spread of the disease.
Routine vaccination of all sheep on a property is recommended only where the disease exists – ring us to discuss your particular situation. The vaccine is live, meaning non-vaccinated stock are vulnerable to infection. Click here to refer to our fact sheet on vaccinating lambs.
- A single scabby mouth vaccination protects sheep for life.
- Vaccinate lambs at marking.
- Don’t vaccinate pregnant ewes within 6 weeks of lambing.
- Scabby mouth vaccination is essential for sheep destined for live sheep export.