150 DISEASES WHOSE CAUSE IS UNKNOWN 



HOG CHOLERA 



The cause of hog cholera has been determined to be a virus that 

 will pass through a bacteria proof filter. King, Baeslack and Hoff- 

 mann state that they have constantly found by dark field examina- 

 tion a spirochete in the blood of hogs (40 cases) affected with hog 

 cholera but did not find it in the blood of hogs (48 cases) not 

 affected with hog cholera. The spirochetes were not found in 

 large numbers, but were found with less difficulty in the acute 

 form of the disease and when it was at its height. The spirochete, 

 which they named Spirochaeta suis, later Sp. hyos, is relatively 

 large, averaging from 5-7 micra in length by one micron in width. 

 The blood was drawn aseptically from the caudal artery into 

 sterile sodium citrate solution and kept in the incubator until the 

 examination was completed. Dilution was in the proportion of 

 about one part of blood to ten or fifteen of citrate solution. 



The changes occurring in the blood in hog cholera were studied 

 by King and Wilson. They found the red corpuscles and hemo- 

 globin decreased. The red corpuscles varied from 2.8 to 9 millions 

 with an average of 5.84 millions. "The hemoglobin varied from 50 

 to 82, average 72. There was an increase of onvi minute in the 

 average time of coagulation. 



The leucocytes were decreased. The number varied from 7,200 

 to 23,600 with an average of 15,515. The decrease was in the 

 lymphocytes, polymorphonuclears and eosinophiles. The large 

 mononuclears and mast cells were increased. The lymphocytes 

 varied from 16.5 to 74.2 per cent., average 50.3; the large mononu- 

 clears 2 to 42 per cent., average 11.3; polymorphonuclears 10 to 70 

 per cent., average 31.8; eosinophiles to 16 per cent., average 3.5 

 and mast cells to 18.1, average 3.5. 



EQUINE INFECTIOUS ANEMIA 



The cause of equine infectious anemia has not been discovered. 

 It is so minute it will pass through a bacteria proof filter (Carree 

 and Valle). The disease may be transmitted by the inoculation 

 of blood or urine (Caree and Valle\ Francis and Marstellar and 

 others) of a diseased animal. It is probable that the disease in 

 America known as swamp fever is the same. 



