Orf virus infection of workers in the meat industry.

Two hundred and thirty-one cases of orf were reported in one year from 18 meat works slaughtering lambs and sheep. This represented 1.4 percent of the total employees at these works and 4 percent of those working on the mutton slaughter board. One hundred and nineteen of these reports were accompanied by samples of the lesion and 85 percent of lesions contained orf virus particles as determined by electron microscopy. The tasks that led to the greatest risk of contracting orf were related to handling pelts and/or wool. Ninety-five percent of lesions were on the hands. The risk of a worker contracting orf did not decrease with the number of years employed at the meat works and 18 cases of re-infection were reported. Control of the disease in man in the meat industry will be difficult in the short term. In the long term control of the disease in man will rely on control of the disease in sheep. Alternative vaccines for sheep will need to be found.