INFECTIOUS DISEASES 339 



and 2 to 3 microiis in diameter. House mice and pigeons may be suc- 

 cessfully inoculated with the B. of swine erysipelas. 



Period of incuhation. — The period of incubation in natural infec- 

 tion is not less than three days. 



Lesions. — Swine erysipelas may assume a septicemic form and a 

 less acute form. The septicemic form of the disease is so rapidly 

 fatal that there are no distinct characteristic lesions. In these 

 cases there is usually parenchymatous degeneration of the essential 

 organs. In the less acute cases there is an intense gastro-enteritis 

 which may be hemorrhagic or diphtheritic. There is usually tume- 

 faction and edema of the lymph glands and there may be nephritis, 

 hepatitis and myositis. The spleen is usually engorged with blood. 

 The characteristic lesion consists of red purpuric areas on the ears, 

 around the anus or vulva and on the inner surface of the thighs. 



Symptoms. — This disease has a sudden onset. The affected animal is 

 indifferent,, refuses food, retches frequently and may vomit, has a high 

 temperature and may evidence disturbances of the cerebral func- 

 tions. There is marked weakness and a tendency to inco-ordination of 

 the hind legs. The conjunctival mucosa may be injected and the eye- 

 lids swollen. There may be grinding of the teeth and diarrhea is usu- 

 ally present. 



The characteristic symptom occurs on the skin in various loca- 

 tions and consists of red areas three or four inches in diameter. These 

 areas later become purple and may fuse, forming large patches. Vesi- 

 cles appear in the purple areas, especially in those that occur upon 

 the ears or facial region. In some cases the discolored skin areas be- 

 come necrotic and slough. The various symptoms vary in intensity, 

 and in the very acute, rapidly fatal cases and the mild cases the skin 

 lesions may be wanting. 



The course of the disease varies from one to ten days and the 

 prognosis is unfavorable. The mortality averages about 60 per cent. 



Treatment. — Swine that recover from an attack of swine erysipelas 

 are immune. An immunizing serum may be successfully used in the 

 prevention of this disease, and according to reports the serum is also 

 of value as a curative agent. 



Rabies 



Rabies occurs in swine, but is not prevalent. It may occur enzooti- 

 cally, but is much more likely to affect only one animal, or few animals 

 at most, in any one locality. 



