378 DISEASES OF CATTLE. 



Ill the past rinderpest has been supposed to be identical with vari- 

 ous human diseases, ;imong them smallpox and typhoid fever. These 

 suppositions are unfounded, and the view of authorities to-day is 

 that it is a disease of a peculiar kind, not identical with any other 

 known infectious disease. 



The contagion of liruJerpest. — The cause of rinderpest must be 

 looked for among microorganisms — most likely bacteria. The inves- 

 tigations made thus far for this causal factor have been fruitless. 

 However, certain recent experiments would indicate that the unseen 

 microbe is of such dimensions that it is withheld by the dense 

 bacterial filters, but passes through the more porous ones. For- 

 merly it was supposed by various authorities that rinderpest virus 

 appeared spontaneously under the influence of deteriorated feed and 

 long and exhausting drives; also during unusual meteorological con- 

 ditions. This view, however, is no longer maintained. It is probable 

 that in its home in Asia the disease is perpetuated by continual infec- 

 tion of fresh animals, and some authorities go even so far as to believe 

 that the disease would be entirely stami^ed out, even in its native 

 haunts, by a destruction of all sick and infected herds. However this 

 may lie, the success of such an undertaking would largely depend on 

 the nature of the cause. If a strictlv parasitic organism, like the con- 

 tagion of pleuropneumonia, it might be comjjletely extirpated in this 

 way. If, however, the germs or bacteria maj^ live and multiply out- 

 side of the bovine body, in the soil, water, or in some other animal, 

 extirpation would be impossible. 



The virus may be transmitted in a variety of ways, both direct 

 and indirect, from sick to healthy animals. It is said to be present 

 in the ^'arious excreta, such as the discharges from the nose, and the 

 saliva, the urine, and the manure, of the diseased. For months it 

 retains its vitality in a moist state outside the body, and the disease 

 is reported to have developed after feeding hay a year after it had 

 lain in an infected stable; hence manure and the fodder and bedding 

 soiled with discharges may convey it. Persons may carry the ^irus 

 on their shoes, clothing, or implements. Even small animals, such 

 as cats and rats, which frequent barns and stables, have been looked 

 upon as carriers of the virus. 



Cattle are very susceptible to the disease, and in its virulent type 

 all those exposed are said to become infected. Builaloes, sheep, and 

 goats are likewise susceptible, but in a less degree. 



It is also claimed that animals after having passed through one 

 attack successfully resist future attacks. Inoculation with virus is 

 said to produce immunity, but in many cases the process of inocula- 

 tion itself is followed by death. 



Si/m/>tor/h'i. — The symptoms of rinderpest are not very character- 

 istic, and hence the diagnosis of a suspected case in the beginning of 



