Are sheep contagious for sore mouth after the scabs are gone?

Asked April 16, 2013, 10:49 AM EDT

I was recently given some sheep, after looking gift sheep in the mouth I realized the lambs had a slight case of sore mouth. I have had them all quarantined in a pen, so as not to spread the sore mouth. My question is do the sheep continue to be contagious after the scabs are gone or are they only contagious when the infection is active?

Lane County Oregon

1 Response

Unfortunately, regardless of scab status, some of the affected animals may become chronic carriers and serve as a source of infection for the flock. I think your best response at this point is to consider your flock infected and vaccinate all animals. This will cause a (hopefully) mild form of the disease in all vaccinated animals not previously exposed but protect them from the vaccine strain of the virus for a long time. Each new lamb flock will have to be vaccinated annually. Alternatively, you could send the quarantined animals back to their source, clean and disinfect the isolation pen and leave it off limits for a long, long time (maybe forever!). Your footwear, hands, clothing and equipment may have already transferred the virus throughout your premises, however, so selling the new sheep may be pointless at this point. As stated in a very good article about soremouth (http://www.sheepandgoat.com/articles/soremouth.html),
"After a herd is infected, it is difficult to eliminate the disease because the virus can remain stable in the crusts. Scabs that fall from the animals have long been incriminated as the source infection to other animals months or even years later."
Because there are different strains of the virus, you can have a farm-specific vaccine made to protect animals against the strain present on the farm; this is effective but expensive. Contact your veterinarian and discuss the pros and cons and methods of vaccinating your herd at this point. Best wishes!