PSEUDO-ACTINOMYCOSIS OF DOGS 623 



PSEUDO-ACTINOMYCOSIS OF DOGS. 



Streptotrichosu Canum. Actinomyces Canis. 



Definition. A specific disease, caused by the Actinomyces 

 canis, cliaracterized by an inflammation of serous mem- 

 branes, and abscess formation of the subcutaneous tissues. 



Occurrence. This disease is not of frequent occurrence in 

 dogs. A few cases have also been noted in cats. 



Etiology. The specific virus, Actinomyces canis, produces 

 long divided filaments, which are easily stained by the Gram- 

 Weigert method. Sometimes they form club-shaped bodies. 

 On artificial media the fungus grows at the body temperature. 



Pathogenicity. When pure cultures are injected intra- 

 peritoneally into mice, they produce at the point of inoculation 

 nodules of varying size (pea to bean) containing pus. Sub- 

 cutaneous injections into rabbits cause at the point of injec- 

 tion nodules which form abscesses. The same condition may 

 be produced in dogs by subcutaneous injections. 



Pathology. The lesions usually found are in the pleura or 

 peritoneum. They consist of an exudate of reddish color 

 collected in the body cavity, containing numerous small, 

 white, pin-point nodes. On the serous membrane will be a 

 number of small nodules, and on the pleura fibrinous exudate. 

 The lungs often contain a number of pea-sized nodes with 

 caseous centers. 



Abscess formation occurs in different parts of the body, 

 particularly in the subparotid region, the vagina, or in the 

 subperitoneal connective tissue of the pelvis. The abscesses 

 contain a grayish turbid mass in which are many of the 

 characteristic granules. The abscesses usually heal after 

 discharging their contents. The spleen, kidneys and heart 

 muscles often show nodular lesions. Arthritis with pus 

 formation is seen in some cases. 



Symptoms. The disease during the early stages does not 

 present any characteristic symptoms. Later, however, 

 there will be evidence of chronic inflammation of the serous 

 membranes with collections of fluid in the thoracic and 

 abdominal cavities. As the disease progresses, the animal 

 shows general emaciation, weakness, and the presence of 



