480 VETERINARY BACTERIOLOGY 



considerable risk. An efficient and safe method of immunization 

 or vaccination has not been developed. 



Transmission. The organisms gain entrance through contact 

 of healthy animals with the saliva or other secretions of an in- 

 fected animal. They may be transmitted to young animals or to 

 man in milk. 



Virus of Rinderpest or Cattle Plague 



Disease Produced. Cattle plague, rinderpest, or contagious 

 typhus in cattle, rarely in sheep, goats, and camels. 



Nocard, and later Tartakowsky, observed that the body fluids 

 in animals having this disease contained no visible microorgan- 

 isms, but were infective. Nicolle and Adelbey established that 

 these fluids, if thinned with water, could be passed through the 

 coarser Berkefeld filters, but not through a fine-pored Chamber- 

 land, without losing their virulence. 



Distribution. The disease has been reported from a large 

 portion of the area of Europe. It is endemic in southern Asia, 

 is known in the Philippines, and has caused great losses in Egypt 

 and in Southern Africa. It has not gained entrance to the United 

 States. 



Character of Virus. It is both ultramicroscopic and filterable. 

 It has not been cultivated. Blood sealed hermetically in tubes is 

 found to retain its virulence for months. The virus is destroyed 

 by desiccation or by heating to 58 to 60. It may survive in 

 putrefying flesh for considerable periods. It is easily destroyed 

 by disinfectants. 



Pathogenesis. The virus is present in all the body tissues 

 and excretions. One one-thousandth of a gram of blood from 

 an infected animal at the height of the disease has been found 

 sufficient to reproduce the disease in a susceptible animal. The 

 infection is an acute, highly fatal fever, in which there are croupous 

 diphtheritic lesions of the intestinal tract. It is typically a cattle 

 disease, but occasionally attacks other animals. 



Immunity. Animals which recover spontaneously from the 

 disease are highly immune, and the blood has some power of pas- 

 sive immunization when injected into another animal. Vac- 

 cination with the nasal secretion of sick animals into the tails of 



