264 VETERINARY HYGIENE 



are naturally less exposed to infection than those eating uncooked 

 fodder; they are, however, not immune, as in some instances they 

 have become infected from actinomycotic lesions of the udder. 

 In general, however, as might be expected it is more often seen in 

 stalled animals than in animals at pasture, and in winter and spring 

 corresponding to the season of dry feeding. In man infection has 

 occurred owing to the habit of chewing straws, and also it is said 

 by inhalation during threshing. 



The course of the disease is always chronic and may extend 

 over months or years, though with suitable treatment most cases 

 recover. That the disease is only slightly contagious is evident 

 from clinical experience and from the experiment of Salmon who 

 caused 21 healthy animals to be closely stalled with diseased animals 

 for four months, with the result that none of the former became 

 affected. 



The actinomyces shows considerable resistance to destructive 

 agencies, e.g., cultures remain alive at ordinary room temperature 

 for a year or more, and dry " spores " withstand continuous ex- 

 posure to sunlight for 238 hours (Berard and Nicolas).* J. Russell 

 Greig made careful post-mortem examinations of over sixty cases 

 of bovine actinomycosis. He found that there were more or less 

 extensive lesions present in the stomachs (rumen and reticulum) 

 in 25 per cent, of cases, with in many instances metastatic infection 

 of the relative lymph glands. In the great majority of such cases 

 primary lesions were found within the buccal cavity, usually on the 

 hard palate, gums and commissures of the mouth. The tongue 

 was affected in only 15 per cent, of cases. In one case there was 

 a generalisation of the disease apparently confined to the systemic 

 lymphatics, and in two cases primary but extensive lesions of the 

 skin were met with. The lungs and pleura and the liver in the case of 

 stomach infection are also fairly commonly seats of the lesions. The 

 above findings suggest, as Russell Greig points out, that actinomy- 

 cosis is a much more common affection of cattle than is generally 

 supposed. When extensive infection of the stomachs exists it is 

 accompanied with great emaciation, the animal giving a clinical 

 picture resembling that of the advanced stage of tuberculosis. 



PREVENTIVE MEASURES. The proper drainage of low damp 

 pastures is indicated. If numbers of cases are appearing, it would 

 be advisable to steam or soak the food with the object of softening 

 its consistency and so lessening the liability to traumatism. 

 Though direct inoculation from one animal to another does not 

 appear to be frequent, precautions should be taken to isolate 

 * Hutyra and Marek, Spec. Path., Vol. I., p. 645. 



