402 DISEASES LOCALIZED IN CERTAIN ORGANS 



several years, attempts have been made to immunize arti- 

 ficially horses against the disease. 



(a) Immunization. — ^A serum produced from horses hyper- 

 immunized with graduated intravenous doses of virulent 

 strangles streptococci, is recommended to produce a passive 

 immunity. It is given in 20 to 30 c.c. doses subcutaneously. 

 The immunity produced, however, lasts only about a month. 

 When injected during the incubation period of the disease 

 it does not prevent its development but is said to reduce the 

 severity of the attack and favorably modify sequels, fewer 

 horses being left unsound. 



(6) Therapy. — Daily doses (20 to 30 c.c.) of the immuniz- 

 ing serum seem to have a good effect upon the course of 

 strangles when given to animals suffering from the disease. 

 After its use the patient appears brighter, the nasal discharge 

 less and the abscessing of the lymph glands prevented. 



A vaccine prepared from the Streptococcus equi, so treated 

 as to kill the organism, is used therapeutically in strangles. 

 The dose is 1 to 10 c.c. subcutaneously, repeated in seven to 

 ten days if necessary. Its use is most valuable in subacute or 

 chronic cases in which it promotes the healing of abscesses 

 and reduces the nasal discharge. 



MALIGNANT HEAD CATARRH OF THE OX. 



Gangrenous Coeyza. Coryza Gangrenosa Bovum. 



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

 the ox and buffalo, characterized by an inflammation of the 

 mucous membrane 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 unsanitary 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 Eiu-ope. 



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

 assumed that the virus which causes the disease reduces the 



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