646 IOWA DEPARTMENT OF AGRICULTURE 



such an organization would be supported. It was necessary to substitute 

 something, so far as this could be done, and four veterinarians have 

 been doing educational work, and in this way securing more or less uni- 

 formity in ideas and co-operation. 



Since 1884, this state has experienced three severe outbreaks of hog 

 cholera, which appeared in the form of "waves." The first came in 1886, 

 the second in 1897, and we are just passing through the third. A 

 short study of conditions convinced us that the immediate problem was 

 to save all the Iowa hogs possible, and that the more deliberate and 

 thorough work of complete suppression should be taken up when the 

 disease is at its minimum. Our efforts, therefore, were designed to meet 

 the existing «onditions. Our plan must necessarily include the state as 

 a whole. 



The chief reliance was placed in vaccination and education. Vaccina- 

 tion is the practical application of the scientific fact that a hog once re- 

 covered from hog cholera will not contract the disease a second time, due 

 to substances which circulate in the blood. If these substances are 

 sufficiently concentrated, the blood will protect susceptible hogs when in- 

 troduced into their body. Concentration can be secured by intensifying 

 the exposure. The animal receiving these substances, however, soon 

 eliminates them, and again becomes susceptible, while the animal pro- 

 ducing them has lasting protection. Therefore, in order to make the tem- 

 porary protection permanent, the animal thus protected is exposed to in- 

 fection usually by inoculation. 



The latter method, commonly called the simultaneous treatment, is 

 recommended in all cases except pregnant or nursing sows, sucking pigs, 

 or when only temporary immunity is desired. Our reports indicate that 

 pigs from susceptible sows are more easily permanently immunized than 

 those from immune sows. In a considerable number of herds, the pigs 

 under sixty pounds from immune sows have lost their immunity in six 

 to ten weeks' time, especially when a small dose of virus was given. 



Too many people do not appreciate that in order to withstand the 

 simultaneous treatment, the hogs should not be suffering from some de- 

 bilitating condition. Too frequently we hear a statement as follows: 

 "My hogs are not doing well, guess I will vaccinate them," and vaccina- 

 tion is ordered, whether the hogs are suffering from hog cholera, lung 

 worms, intestinal worms, improper rations, mange, or any one or more 

 of debilitating conditions. The results in such cases are usually more 

 or less unsatisfactory. We should not lose sight of the fact that in order 

 to secure the desired results, the hogs should be in the best possible 

 condition, and that every detrimental influence operates in favor of the 

 virus and counter to the serum. Therefore, every herd should be care- 

 fully studied by a competent person, and serum and virus used according 

 to indications. Anti-hog cholera serum is specific in counteracting the 

 virus, and we have no right to assume that it will prevent any of the 

 numerous other infections which may accompany or are a part of hog 

 cholera. 



