FOURTEENTH ANNUAL YEAR BOOK— PART VI. 521 



been carried to the hogs in the clean yard, and they got sick, while the 

 man with the filthy yards has escaped the virus. 



Typhoid fever in man is quite similar to hog cholera in hogs. The 

 most vigorous man is more apt to take an acute case of typhoid fever. 

 A vigorous man of twenty-five or thirty years generally has it pretty bad, 

 while a weakly man may survive or not take the disease when he has 

 an opport 'nity. So the important thing for us to remember in connec- 

 tion with the spread of hog cholera is that we must be careful not to 

 bring the virus to our place. In the work which has been carried on in 

 some of the counties of Iowa by the federal government, in co-operation 

 with the State College and the state veterinarian, it has been observed 

 that while the veterinarians and the college people in charge of this 

 work have been constantly telling the farmers to be careful, it is an 

 extremely hard matter to sliow the people what they ought to do, or get 

 them to do it, in order to prevent the spread of hog cholera. 



In Dallas county it has been shown that a number of outbreaks of 

 hog cholera were brought about by the farmer. He would haul his well 

 hogs to the nearest market, and it seems there is a stock yards there in 

 which to unload the hogs. The man has to drive his team into the 

 yards where the hogs run. Several farmers near that town have had 

 hog cholera break out in their herds in eight or ten days after they had 

 driven their hogs there. They have gotten out, walked around the yard, 

 let the hogs out, and then driven the wagons back to their own farms; 

 and the supposition is that they carried the virus from the infected 

 stock yards to their own farms, and their hogs became exposed in that 

 way. In a year like this every stock yard in the country must be re- 

 garded as infected; and consequently you see the danger of going into 

 that yard. 



Another source of infection which seems to play a more or less im- 

 portant part is the carrying of the virus by farmers in changing work. 

 You are obliged to change work to carry on certain farm procedures. 

 Y'ou change work when you build your silo, when you thresh, when you 

 shell corn; and you have a number of farm operations in which it is 

 necessary for you to have more help than you have on your own farm; 

 and consequently you change work with your neighbors. There is great 

 danger in a case like this of carrying hog cholera from one farm to an- 

 other. I know of numerous instances in different years where hog 

 cholera has followed up a threshing crew. You can readily see that if 

 you drive your team into your neighbor's yard where hogs are dying, 

 and then drive it back into your own yard with a load of corn, where 

 the hogs are running around, there is a chance for them to become in- 

 fected. Or if you go into your yard with infected boots on, you carry 

 enough litter from the infected yard to convey disease. If you have to 

 change work with a neighbor having hog cholera, you should not drive 

 your team into the infected yard. You ought to wear different clothes 

 and foot covering from what you wear around your own premises. 



There are one or two other sources of infection that you can readily 

 guard against. You can guard against going away from home and buy- 

 ing hogs and putting them into your own herd. In some instances we 

 ^ound that that started up an outbreak of hog cholera. If you have to 



