ACTINOMYCOSIS— LUMPY JAW 453 



food, will become victims. Stable-fed cattle are often 

 infected by forage fed in a dry state, but which was grown 

 on lowlands subject to overflow. While clinically the disease 

 is more important to the surgeon than to the internist, 

 it not infrequently affects internal organs (lungs, liver, 

 stomach), and leads to the condemnation of the carcass in 

 the abattoir. 



Etiology. — The cause of the infection is a thread-like 

 fungus known as the Streptothrix actinomyces or the Actino- 

 myces bo vis. A common name for it is the ray fungus. 

 This fungus grows on various kinds of grasses, particularly 

 on the awns and glumes of barley and related plants, especi- 

 ally when these have grown on bottom lands ' subject to 

 overflow. 



Natural Infection. — Infection takes place through the 

 mucous membrane, usually of the mouth, or through wounds 

 in the skin. Forage infested with the fungus, provided it 

 contains sharp awns or glumes or the sharp cut ends of 

 coarse straw (stubble), easily cuts the mucous membrane 

 introducing the fungus into the wound at the same time. 

 Cattle from the Southwest suffer from eating cactus, the 

 sharp spines of which wound the mouth. Obviously when the 

 mucous membrane of the mouth is edematous and tender as 

 occurs when the deciduous teeth are being shed, the oppor- 

 tunity for infection is greatest. Sometimes the infection 

 enters the alveolus of a tooth leading to the development of 

 disease of the bone of the jaw (periostitis, osteitis, osteomye- 

 litis). If the mucosa of the. cheek is infected, either abscesses 

 (young animals) or connective-tissue growths appear about 

 the head. If the tongue is invaded, either a diffuse, connective- 

 tissue proliferation follows or multiple, circumscribed, actino- 

 mycotic foci result. In swine sharp-pointed, plant particles 

 may enter the crypts of the tonsils and set up infection. 

 Otherwise swine are most commonly infected through skin 

 wounds. Sows with pendent udders pasturing on stubble 

 fields often suffer from udder actinomycosis, and pigs are 

 infected through castration wounds especially if allowed 

 access to straw stacks. The infection of internal organs may 

 be primary or secondary. Actinomycosis may involve the 



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