452 CHRONIC INFECTIOUS DISEASES 



involved, especially the liver, spleen and kidneys, and more 

 rarely the mesenteric lymph glands. 



Symptoms. — The symptoms are rather vague. Most 

 cases are discovered in the slaughter house. Where the 

 affection involves superficial lymph glands, tumors appear 

 on the surface of the body, most frequently in the prescapular 

 and precrural regions. They are about the size of an average 

 potato and are not sensitive on palpation. The condition 

 of the sheep otherwise may be normal except that the 

 enlarged lymph glands may interfere with locomotion. 



When the lungs are affected the patient shows cough, 

 dyspnea, anemia, emaciation and ultimately cachexia and 

 death. 



Course and Prognosis. — ^The course is prolonged, the disease 

 lasting for weeks or months with a gradual wasting of the 

 patient. The mortality varies but may reach, especially 

 among lambs, as high as 70 per cent. 



Treatment. — ^Medicinal treatment is of no avail. The 

 disease may be presented to a certain extent by a thorough 

 disinfection of the navel immediately after birth and of 

 wounds surgical and accidental. Vaccination has been 

 successfully practised, using an attenuated strain of the 

 bacillus. When feasible the infected droppings should be 

 rendered innocuous by disinfection or removal to fields not 

 used for sheep. 



ACTINOMYCOSIS. LUMPY JAW. 



Definition. — Actinomycosis is an infectious disease due to 

 a specific fungus and characterized clinically by the appear- 

 ance of either connective-tissue enlargements, bone growths, 

 or abscesses which usually occur about the head of the animal 

 affected. The disease is not contagious. 



Occurrence. — ^While most common among cattle, actino- 

 mycosis occurs occasionally in swine and rarely in horses. 

 Cattle which have access to straw stacks, especially of 

 barley or bearded wheat, are most often attacked. It may 

 happen that a whole herd of steers or heifers running about 

 a straw stack, which serves them for shelter and in part 



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