The feces of infected animals retain their virulence for sixty-five to 

 ninety-five days. My personal experience would indicate that it is 

 unsafe under the climatic conditions encountered here (Tennessee) 

 to endeavor to raise unvaccinated hogs on a farm or other infected 

 premise until after an interval of at least twelve months has elapsed 

 from the last outbreak. Disinfection of premises as ordinarily prac- 

 ticed is valueless in eliminating- the danger of reinfection. In fact, 

 in my opinion, the disinfection of premises by any method or under 

 any circumstances is of doubtful value in controlling cholera infec- 

 tion on a farm. It is often misleading in affording false security from 

 the lurking danger of subsequent outbreaks. 



Carbolic acid is not at all efficient in disinfecting premises, pens, 

 cars, etc., where hog cholera infection exists. Cresol Compound U. S. 

 P. in 3 per cent solutions should be used freely. For dipping or spray- 

 ing the hogs 2 per cent cresol is recommended. 



The best advice bearing on this point I am able to give is to do one 

 of two things : either raise "immunes," or retire from the hog-raising 

 business for at least one year— preferably the former. 



Methods by Which Hog Cholera Spreads. 



Remember that the infection must always come from the outside. 

 The disease never arises spontaneously. The urine is much more 

 virulent than any of the other body secretions or excretions. The 

 feces are also heavily laden with infection. The infection enters 

 through the digestive tract. 



The infecting agent of hog cholera is just as virulent and danger- 

 ous to hogs as is the virus of smallpox to people. Various animals, 

 such as dogs, rabbits, cats, buzzards, crows, pigeons, and other birds, 

 may carry the germs to another herd. Often when a hog dies the 

 owner thinks little of it and the carcass is allowed to remain in the 

 pen to be eaten by the other hogs. Or the carcass is left in the field 

 as a prey to other meat-eating animals. This hog may have been 

 the first to be infected and die of hog cholera, and by this method of 

 disposition the seed is sown for a good crop of cholera in the neighbor- 

 hood. In known outbreaks carelessness in the disposition of dead car- 

 casses may result in useless spread of the disease. The germs may be 

 carried on the shoes or clothing of anyone handling the hogs to herds 

 subsequently visited. Stock cars used for shipping hogs are to be 

 considered cholera-infested unless thoroughly cleaned and disinfected. 



Visiting Infected Places. — It is dangerous for the swine owner to 

 visit infected places and return to his own herd without at first dis- 



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