272 , DISEASES OF THE SKIN 



LIP-AND-LEG ULCERATION OF SHEEP. 



Necrobacillosis . 



Definition. — Necrobacillosis is an inflammatory process 

 which terminates in necrosis of the skin and mucous mem- 

 branes attacking the mouth, lips, legs, feet and external 

 genital organs of sheep. 



Occurrence. — The disease is closely allied to necrotic sto- 

 matitis of calves and pigs. It attacks sheep on the Western 

 ranges, particularly in Montana and Wyoming, where it 

 sometimes assumes a malignant form, causing considerable 

 losses through deaths, lost service of bucks, and abortion in 

 ewes. While during favorable weather and with abundant 

 feed the disorder is mild, where opposite conditions prevail 

 it is often malignant, leading to the loss of from 10 to 20 

 per cent, of the sheep herd. The disease has been introduced 

 into the Eastern States by the importation of Western sheep. 

 It also exists in England, on the continent of Europe, and has 

 been reported from New Zealand. 



Etiology. — The cause of the disease is the Bacillus necro- 

 phorus, which enters skin lesions often made by cactus or 

 other sharp-pointed particles of plants. The disease is most 

 frequent during cold seasons and among sheep which are 

 pasturing among thistles, cacti and briers. It is transmissible 

 both by natural and artificial inoculation. 



Symptoms. — From a clinical standpoint four forms are 

 described : (a) the lip-and-leg, (b) the venereal, (c) the foot- 

 rot, (d) the sore mouth of lambs. 



(a) Lip-and-leg Form. The first stages are those of acute 

 inflammation of the skin, usually of the lips. Pustules develop 

 which undergo puriform softening, erupt and lead to ulcers. 

 The ulcers are usually covered with exudate which dries to 

 form dark gray-colored crusts. By confluence a large, irregu- 

 lar shaped scab forms along the lip margins and extending 

 upwardly in front to the nasal openings. The lips are swollen 

 and present a scabby or warty appearance. The appetite 

 usually remains good, though the prehension of food is difficult 

 owing to the sensitiveness of the lips. In some cases the 



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