128 ANNUAL REPORT OF THE Off. Doc. 



or higher. There is a discoloration of the skin over the abdomen 

 under the thighs, front legs and around the ears. The animal shows 

 an inclination to bur}^ itself under the straw and in cold weather 

 arches its back, shivers and usually avoids the rest of the herd. The 

 hind feet are kept close togetlier or crossed. There is loss of ap- 

 petite, diarrhoea or constipation, cough, rapid loss or flesh, difficult 

 breathing, wobblj^ g^^^, gummed condition of the eyelids and some- 

 times a discharge from the nostrils. No one set of symptoms are 

 always presented and to be relied upon to determine whether or not 

 an animal is affected with hog cholera. Any of the above symptoms 

 may or may not be present. 



The skin of a hog that has died of cholera is usually red or purple. 

 On opening the carcass blood is found in the tissue just under the 

 skin. The lymph glands, or "kernels" as they are sometimes called 

 by the stock owner, are swollen, inflamed and sometimes bloody. 

 The lining of the chest and abdominal cavities may be inflamed and 

 covered with small blood spots. The lungs and intestines are in- 

 flamed. In some cases the lungs show that the animal had suff'ered 

 from pneumonia and along the inside of the intestines, button shaped 

 ulcers may be found. The kidneys are inflamed and their surface is 

 speckled like a turkey's egg. 



In the first described or acute cases of cholera, death is due to hog 

 cholera infection alone. In chronic cases death is due to the presence 

 of other organisms which are found in the normal hog's carcass but 

 are kept in check by the animal's natural resistence. They overcome 

 this resistance and cause tissue destruction and other symptoms 

 of disease only w^hen the animal's vitality has been reduced by the 

 hog cholera infection. 



The acute form of hog cholera is due to cholera infection which is 

 a filterable virus. The organisms are so small that they cannot be 

 seen under the most powerful microscopes. They pass through the 

 finest porcelain filter. 



The chronic form of hog cholera is due, first, to the filterable virus, 

 but the conditions that are so noticeable are due to other bacteria : 

 Principally bacillus suipestifer and bacillus suisepticus. The former, 

 bacillus suipestifer, causes the ulcerations on the intestinal mucous 

 membrane, the necrosis of tissue, and the swelling, inflammation, etc., 

 of the lymph glands. The latter, bacillus suisepticus, cases the lung 

 lesions. 



It is not unusual for those who liave had limited exj^erieuce with 

 hog cholera to fail to recognize the disease in some instances. A 

 number of hogs may die suddenly and practically no signs of disease 

 will be found Avhen a carcass is opened. Another may lose a number 

 of hogs all of whicli showed every indication of having pneumonia 

 and the lungs are found afi'ected when the carcass is opened. No 

 other signs of disease are found and the inexperienced man would be 

 led to believe that he was dealing witli a contagious form of pneu- 

 monia or might term it, as was formerly the practice, an outbreak of 

 swine plague. There is a third class of cases frequently found. The 

 symptoms of disease shown before death, together with the findings 

 when the carcass is opened, (such as necrotic areas, ulcerations of 

 the intestinal tract, etc.) make up the case that is easily recognized 

 as hog cholera. 



