I82 



HOG CHOLERA 



i6. Rabbits inoculated with cul- 

 ture of an attenuated variety live 

 from lo to 20 days or recover. 

 The lesions are enlarged spleen, 

 and infiltration of the follicles in 

 Peyer's patches. 



17. In guinea-pigs the lesions 

 are practically the same as in rab- 

 bits. Death occurs in from 7 to 12 

 days. 



18. Pigs are not usually 

 affected by subcutaneous injection 

 of small quantities of culture. If 

 the pigs are killed within i to 3 

 weeks the bacilli are found in the 

 local lesion and certain of the lym- 

 phatic glands. Fatal results are 

 reported in a few cases by these in- 

 jections. 



19. Feeding cultures to pigs 

 which have fasted for 24 hours 

 produces extensive intestinal lesi- 

 ons with fatal results. 



20. Intravenous inoculation in- 

 to pigs causes either an acute sep- 

 ticaemia or a chronic form of the 

 disease in which are produced 

 quite typical round, firm, elevated 

 ulcers. 



16. Rabbits inoculated with a 

 culture of an attenuated variety 

 will live from 4 to 10 days. The 

 lesions are local infiltration of pus 

 cells with pleuritis, pericarditis or 

 peritonitis. 



17. Guinea-pigs are slightly 

 less susceptible than rabbits. There 

 is more local reaction. Death oc- 

 curs in from i to 4 days. 



18. Pigs are not usually affected 

 by the subcutaneous injection of 

 small -quantities of culture. The 

 bacilli are not found except in the 

 local lesion. In a few cases fatal 

 results are reported. 



19. Feeding cultures to pigs 

 usually produces no effect. 



20. Intravenous inoculation in- 

 to pigs usually produces a septic 

 form of the disease which kills in 

 from I to 2 days. Inoculation into 

 the lungs causes pleuritis, usually 

 accompanied by pneumonia. 



§ 139. Prevention. As hog cholera is caused by a 

 specific organism the first fact to be determined is to find the 

 channel or means b}' which it can be carried from an infected 

 to a |non-infected herd. The thorough investigations which 

 have been made in the United States Bureau of Animal Indus- 

 try have shed much light upon this subject. The observa- 

 tions of more recent years have confirmed the conclusion 

 reached in the earlier reports of the Bureau concerning the 

 means of spreading this disease. With these results, the 

 pointing out of the ways by which the virus may be dissemin- 

 ated and the methods necessar}" for checking its .spread is no 

 longer questionable and there is a certainty that it can be kept 

 away from individual herds even in the midst of wide spread 



