312 VETERINARY HYGIENE 



Total Number Number Percentage 



Class of Pig. in Infected * m . Affected 



Herds. of Total. 



Boars 225 27 12.0 



Sows 3,051 423 13.9 



Unweaned pigs 5,500 289 5.25 



Fatting pigs 13,514 2,592 19.2 



Store pigs 12,564 1,861 14.8 



The Chief Veterinary Officer draws attention to the fact that 

 stores are also attacked and that unweaned pigs do not always 

 escape. The author has seen a very acute outbreak in unweaned 

 pigs less than a fortnight old. 



Infection usually occurs by ingestion, probably through the 

 medium of excreta. On the Continent the disease has been noted 

 to occur following castration. With pigs housed in cement 

 concrete sties with cement floors and which never leave the sty 

 until they go to slaughter and where all the food is cooked, it is 

 possible that the contagium is brought in on straw used for bedding. 



PREVENTIVE MEASURES. These consist of isolation of affected 

 pigs, and deep burial of the dead. Once an outbreak has occurred it 

 is a good plan to keep the affected and suspects in sties and so 

 lessen risk of grossly contaminating pastures. Sties and feeding 

 appliances must be disinfected. Infected litter must be kept apart 

 from other litter and treated with quicklime or burnt. No fresh 

 pigs should, of course, be introduced until the outbreak is at an end. 

 Since swine erysipelas is due to a saprophytic organism normally 

 present in the soil it will never be completely stamped out, and 

 owing to this the Chief Veterinary Officer, Board of Agriculture, 

 does not advocate its compulsory notification, stating that if it were 

 adopted it " would probably result in a maximum amount of incon- 

 venience to pig owners with a minimum amount of success." 



One attack produces immunity. Although in this country one 

 does not often see extensive outbreaks such as occur from time to 

 time on the Continent, these do occur. 



On the Continent methods of producing immunity have been 

 practised to a large extent. In France at one time (1882) Pasteur's 

 method was used, which consisted in injecting with a certain interval 

 two living vaccines attenuated in virulence for the pig by means 

 of passage through rabbits. Pasteur's method was found to be 

 not entirely free from danger. More satisfactory is the method of 

 Lorenz (1893), which consists in injecting a dose of protective 

 serum obtained from hyperimmunised horses, followed a few days 



