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Biological Therapy 



weaning time. Infection occurs through the digestive tract 

 from contaminated foods and water. 



ETIOLOGY. B. ovisepticus, a member of the hemor- 

 rhagic septicemia group of organisms. 



SYMPTOMS. An acute form of the disease is observed 

 in young sheep whereas in older animals it tends to chron- 

 icity with the general symptoms of cachexia. 



The acute form is ushered in by a high temperature, 

 shivering, inappetence, dyspnoea, trembling of the muscles 

 and colicy pains. Death generally occurs in one to three 

 days. If the attack is less acute pulmonary symptoms de- 

 velop. These consist of labored breathing, discharge from 

 the eyes and nose, followed by enteric disturbances, particu- 

 larly colic and diarrhoea. Petechiation and cyanosis of the 

 visible mucous membranes is at times followed by ulceration, 

 particularly of the tongue and cheeks. The mortality in 

 the active type is from ninety to one hundred per cent. 



In adult sheep the disease tends to be less acute or the 

 chronic type may follow an acute attack. The symptoms of 

 chronic pneumonia predominate, although these may be 

 associated with swelling of various parts of the body, par- 

 ticularly the joints. Coughing, nasal discharge and labored 

 breathing are pronounced. Emaciation is progressive and 

 persists until death. 



LESIONS. Petechia and hemorrhages occur on all 

 serous surfaces and are particularly marked on the kidneys, 

 heart and lungs, while the lymphatic glands are hem- 

 orrhagic. The glands are at times completely engorged with 

 blood while subcutaneous hemorrhages in any part of the 

 body are by no means rare. All mucous membranes are 

 hyperemic and somewhat thickened. The lung involvement 

 varies from petechiation, red and gray hepatization to 

 pleuropneumonia, while the bronchi may be filled with 

 bloody mucus. An excessive amount of straw-colored fluid 

 may be found in the abdominal or pleural cavity, in which 

 case an endocarditis is quite regularly observed. 



In the chronic form, observed most frequently in older 

 animals, large areas of lung tissue and pleura are involved. 

 This involvement progresses from hepatization to necrosis 

 which is marked by yellow caseation surrounded by layers 

 of connective tissue. In some, these lesions are alDsent and 

 are replaced by enteric changes and the lesions of a toxemia 

 associated with anaemia. 



