HOG CHOLERA— SWINE FEVER 329 



disease breaks out it is spread, as noted, by the urine, feces, 

 and other discharges of the sick, and by careless disposition 

 of the dead (throwing carcasses into water-ways or leaving 

 them on the fields; too shallow burial, incomplete cremation, 

 etc.)- Hauling the carcasses in wagons through the premises 

 and along the roadways is a further factor in the spread of the 

 disease. It is a common practice when hog cholera is dis- 

 covered to exist on a farm for the owner to attempt getting 

 rid of the disease by selling those hogs which are in a market- 

 able condition. Too often a close discrimination between 

 the infected and uninfected is not made. In transit or soon 

 after arrival at their destination the disease may break out, 

 infecting the railway cars, shutes, pens, etc. Hog cholera, 

 therefore, is spread over great areas, and especially along 

 lines of traffic. 



A transmission of the disease along the course of a flowing 

 stream is probable, the current carrying the infection. 



Necropsy. — (a) Septicemic Form. — Lesions, as in hemor- 

 rhagic septicemia. Petechise and ecchymoses of the skin, 

 serous membranes and of the mucous membranes of the 

 gastro-intestinal tract, especially of the bowels. In the latter, 

 accumulations of clotted blood may be found; the lymph 

 glands are swollen and blood-shot; the parenchymatous 

 organs congested, the spleen little if at all swollen. The 

 petechise over the kidneys give them a spotted appearance, 

 known as "turkey-egg" kidney. On the serous membranes 

 fibrinous exudates appear; catarrh of the stomach and small 

 intestine is also noted. 



(6) The Intestinal Form. — The most characteristic lesions 

 are noted in the large bowels, especially in the cecum. There 

 appear in the mucosa and submucosa, flat, round, hard, 

 elevated, yellowish, greenish-yellow or gray areas of necrosis. 

 The areas vary in size from a pin-head to a twenty-five-cent 

 piece. They are commonly known as "button ulcers." 



(c) Pectoral Form. — The lungs present the signs of pneu- 

 monia (croupous, catarrhal or mixed) with serofibrinous 

 pleuritis and pericarditis. In subacute or chronic cases 

 multiple necrotic foci are present in the lung with caseation 

 Which may involve the lymph glands. 



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