No. 6. DEPARTMENT OF AGRICULTURE. 133 



If we use tlie double Ireatniout we will have to keep on vaccinat- 

 ing? the 3'ouug stock and newly purchased animals from year to year. 

 Tliis expensive procedure would have to be kept up indefinitely and 

 a man would not onl.y be harboring infection upon his premises but 

 would be a constant source of danger to his community and pos- 

 sibly to any section into which his hogs were shipped. 



Hog cholera was reported from sixty counties during the year 

 1914 and fifty-five counties in 1015. It occurred in some parts of 

 the State that in former years were considered free. The losses were 

 only about one-half as much as in former years. Those who are en- 

 gaged in hog raising are becoming more familiar with the symptoms 

 of the disease; what to do when it occurs and how to prevent it. 

 When the disease is reported early in an outbreak the Board is able 

 in most cases to prevent its spread and save most of the animals in 

 a herd. 



Upon receiving information of an outbreak the local veterinarian 

 is furnished serum, free of charge. If the veterinarian is satisfied 

 that the disease is cholera he administers serum to all hogs in the 

 herd that show no symptoms of the disease and also to those that 

 are sick but in which the animal is not so sick but what it may re- 

 cover. In many hog raising states cholera infected blood is injected 

 into those showing no symptoms at the same time the serum is given. 

 Immunity is produced by this method that will last for a year or 

 more. Our experience has shown that sufficient infection is picked 

 up naturally by susceptible hogs in an infected herd to produce just 

 as sure and lasting immunity and there is less danger of spreading 

 the infection. The percentage of losses subsequent to vaccination 

 during the last year was a fraction less than twenty-one per cent. 

 These figures include all losses, including pigs. 



A number of requests have been received to vaccinate hogs on 

 other farms in a neighborhood when the disease breaks out in a 

 nearby herd. This request is seldom complied with for the reason 

 that if reasonable precautions are taken to prevent carrying the in- 

 fection the disease will be avoided. Serum alone given in such 

 cases will produce immunity that will last but about one month. 

 After this time they are again susceptible to the disease. If the in- 

 fection is injected with the serum they will have a longer immunity ; 

 but a herd so vaccinated is an infected herd. The plan is expensive 

 and under usual conditions is unnecessary for the rea.son that the 

 herd should not become infected if it is not vaccinated. This plan 

 of immunization may be necessary in communities where the disease 

 is wide-spread and always present. Fortunately Pennsylvania has 

 never been afflicted with such territory. We believe that it never 

 will be if our people continue to exercise the good judgment in the 

 future that they have shown in the past. Everything possible should 

 be done to prevent infection and where it does occur it should be 

 destroyed as soon as possible. Neither requisite is impossible. 



The following is a record of the amount of serum on hand at the 

 beginning of the rear, the amount produced and used during tlie 

 years 1914 and 1915: 



