Orf

DURING the spring and early summer of 1955 an unusually large number of cases of orf were seen in patients attending the various skin clinics in Northern Ireland. The condition aroused considerable interest, and it is hoped that these notes may prove helpful to local practitioners. Orf is an infective disease, caused by a filtrable virus of the pox group, affecting commonly sheep and goats. The lesions which occur in animals are often secondarily infected with pathogenic bacteria and appear as vesicles and pustules on the skin of the lips, legs, and genitalia, frequently followed by ulceration, suppuration, and necrosis. Orf occurs throughout the world, and though the mortality from the uncomplicated disease is negligible, the rapid loss of weight and condition of the young animal is serious. The infestation of the lesions of orf with the screw-worm fly in Texas causes enormous animal losses (Boughton and Hardy, 1935). The condition in humans is, of course, usually seen amongst those who work with sheep, and was reported for the first time by Peterkin (1937). VETERINARY ASPECTS. There are three main clinical types in sheep (KrAl and Novak, 1953): (a) Labial, which is the most common with small vesicles occurring on the mouth, lip, and nose. These vesicles rupture, are secondarily infected with resulting ulceration, so that eating and swallowing becomes painful and the young animals frequently develop ulcerative gastro-enteritis and broncho-pneumonia. The mortality rate is about 90 per cent. (b) Podalic form or foot rot. The lesions are present between the hoof clefts or in advanced cases up to the knee joint. Ulceration leads to necrosis of ligaments, tendons, and bones. TFhis type is almost always fatal. (c) Genital form affecting the vulva and skin of mucous membrane underneath the tail, and in males the prepuce. The prognosis in young animals is poor, especially if more than one clinical form is present. Prophylactic measures include the maintenance of strict hygiene, periods of observation before putting newly purchased sheep in with old flocks. Vaccination has occasionally been carried out successfully. The treatment is mainly local since the sulphonamides and antibiotics have not proved of any value.