832 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



The organisms are eliminated in the exudates from suppurating 

 buboes, in the sputum in the pneumonic type, and are present through- 

 out the body after death. The dead bodies of human beings and of 

 rats are sources of infection for other rats. There seems good evidence 

 of these animals becoming chronic carriers though showing no symp- 

 toms of disease, and may thus be important factors in maintaining and 

 spreading plague. 



The disease is largely communicated by means of fleas which have 

 become infected by living on other human beings or even upon rats. 



Prophylaxis consists of isolation of pneumonic cases, thorough 

 disinfection involving the killing of fleas, and chiefly the destruction of 

 rats, squirrels, and other animals which may serve as carriers. Haff- 

 kine's vaccination method has also been shown to be a valuable 

 prophylactic measure. 



The serum of immunized animals has been tried as a therapeutic 

 agent and gives encouraging results when administered in the early 

 stages. 



SWINE ERYSIPELAS* 

 Bacterium rhusiopathia suis 



Swine erysipelas is an infectious disease of hogs characterized by 

 red or violet discoloration of the skin and mucous membranes. Swine 

 erysipelas does not exist in the United States but is very prevalent in 

 continental Europe. It is caused by a very small, slender, non-motile, 

 non-spore-bearing bacterium (Bact. rhusiopathia suis) which stains by 

 Gram's method, and grows feebly on the ordinary culture media. 

 Development is best under anaerobic conditions. In gelatin stab 

 cultures, after three or four days, a white growth can be seen along 

 the needle puncture. Radiating from this are a number of delicate 

 tufts which give the growth the appearance of a fine test-tube brush. 

 White and gray mice, white rats, and pigeons succumb to the inocula- 

 tion of minute amounts of the culture. The bacteria tend to collect 

 within the bodies of the leucocytes. This microorganism is closely 

 related to and possibly identical with the bacterium of mouse septicaemia 

 (Bact. murisepticum) . Preventive inoculation with attenuated cul- 

 tures has long been practiced successfully in Europe. 



Prepared by M. Dorset. 



