Dour in e 753 



In these areas of infection the disease has not been definitely 

 traced to its source. The outbreak in Illinois was believed 

 to have been introduced by stallions imported from France, 

 a conclusion which, although unproven, time has not served 

 to change. The affected area in Illinois produced consider- 

 able numbers of grade draft stallions and mares which were 

 sold to go to the West and Northwest for breeding purposes, 

 and, although it cannot be clearly shown, there is good reason 

 to conclude that this outbreak furnished the infection for 

 the others which have occurred in America. 



Nature. Dourine is a highly infectious venereal disease 

 transmitted naturally by coition only. Experimentally it 

 may be transmitted by inoculation to other animals than 

 solipeds. It is due to a protozoan parasite belonging to the 

 trypanosoma group. This parasite, the trypanosomum 

 equiperdum, was discovered by Rouget in 1896, and its re- 

 lation to the disease clearly demonstrated by Schneider and 

 Buffard in 1899. The trypanosome of dourine is a one- 

 celled organism provided with a flagellum at the anterior 

 end. It is about 18 to 26 microns in length and, when ob- 

 served in the living state, is highly motile. It occurs in the 

 blood, the spinal fluid, the discharge from the genital 

 organs, the plaques of the skin, and perhaps in other tissues 

 and fluids of the infected animal. It multiplies by longitud- 

 inal division. When removed from an animal and kept 

 moist, it will live for several days or even a week. 



It is not always easily found. It is said to be most readily 

 discovered in recently formed plaques. Baldrey says, in re- 

 ference to the appearance of the trypanosoma in the fresh 

 plaques, "If these appear, then a positive diagnosis can be 

 made; if not, the case is not dourine." The parasites are 

 said to disappear quickly from the plaques, so that it is diffi- 

 cult or impossible to find them after twenty-four hours. 

 They may be found in the discharge from the vagina or 

 urethra of the infected animal, but it seems that their exis- 

 tence here is not as uniform as in the fresh plaques. Some 

 investigators believe that they are quite uniformly present 

 in the spinal fluid. It is generally very difficult to discover 

 them in the blood. 

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