316 ACUTE GENERAL INFECTIOUS DISEASES 



Cattle may be vaccinated any time of the year. Obviously 

 those already infected should not be treated with anything 

 except serum. Heifers in advanced pregnancy should not be 

 vaccinated. The immunity conferred by attenuated vac- 

 cines should last from twelve to eighteen months. Many 

 cattlemen, however, vaccinate two or more times a year. 

 With aggressins, as noted, one treatment lasts for the natural 

 life of the animal. 



BRAXY. GASTROMYCOSIS OVIS. 



Definition. — An infectious disease of sheep characterized by 

 its short, fatal coiu-se, and due to a specific anaerobic bacillus 

 resembling the blackleg bacillus. 



Occurrence. — Braxy has not yet been reported in the United 

 States. In Norway, Denmark, Iceland, Germany and Scot- 

 land it is common, leading to great losses among yearling 

 lambs. The disease is rarely seen in suckling lambs or in 

 sheep over two years of age. While sporadic cases may occur 

 during the summer months when sheep are on pasture, serious 

 outbreaks take place diu-ing the late fall and early winter 

 months after the sheep have been returned to the fold for 

 the winter. Peculiarly, outbreaks seem more common fol- 

 lowing a heavy frost. 



Etiology. — Braxy is due to the Bacillus gastromycosis ovis, 

 an anaerobe which usually carries a spore near one end, pro- 

 duces gas and stains according to Gram. The germ is patho- 

 genic to guinea pigs, rabbits, and pigeons. While subcutane- 

 ous inoculations generally produce the disease in susceptible 

 sheep, feeding experiments with this bacillus have given 

 negative results. 



Natural Infection. — ^Probably through wounds (in upper 

 digestive tract?) and possibly through the digestive tract with 

 food. The disease is not thought to be spread by drinking 

 water. 



Necropsy. — In peracute cases few, if any, postmortem 

 changes can be noted. In acute cases usually the principal 

 lesions are found in the abomasum and duodenum> the mucous 

 membrane of which is swollen, edematous, and spotted with 



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