366 DISEASES LOCALIZED IN CERTAIN ORGANS 



(a) Active Immunity. — Some good results have apparently 

 been obtained by the use of bacterial vaccines in the preven- 

 tion of strangles. For this purpose either dead or attenuated 

 cultures of the Streptococcus equi have been employed. The 

 use of the non-attenuated culture proved too dangerous. 



(b) Passive Immunity. — A polyvalent antistreptococcus 

 serum has been employed, but as the Streptococcus equi is 

 different from the Streptococcus pyogenes of man and animals 

 it proved ineffectual either as a preventative or cure. A 

 serum made from the cultures of the Streptococcus equi is 

 said to have given better results. Acting therapeutically it 

 diminished the nasal discharge, lowered the fever and stopped 

 in some instances further development of the abscess. It is 

 employed in doses of 10 c.c. 



MALIGNANT HEAD CATARRH OF THE OX. 



Gangrenous Coryza. Coryza Gangrenosa Bovum. 



Definition. — A non-contagious, acute infectious disease of 

 the ox and buffalo, characterized by an inflammation of the 

 mucous membranes of the head, leading to ulceration and the 

 formation of pseudomembranes. The eye is also involved 

 and nervous symptoms are present. 



Occurrence. — Usually occurs sporadically or as a stable 

 miasma, especially in insanitary barns. The disease is rela- 

 tively rare in the United States, but outbreaks have been 

 reported from Ohio, New York, New Jersey and Minnesota. 

 The disease is common in Europe. 



Etiology. — The specific organism is yet unknown. It is 

 assumed that the virus which causes the disease reduces the 

 resistance of the body tissues, especially mucous membranes, 

 through toxins which it eliminates. The ulcers and pseudo- 

 membranes may be due to secondary invading bacteria. 



Natural Infection. — The mode of infection is not yet under- 

 stood. Probably the germs harbored in damp, dirty stables 

 contaminate the food and water and thus be taken in through 

 the digestive tract. Occasionally the disease appears among 

 cattle in pasture, but usually only when the available drinking 

 water is foul. 



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