THE PROTOZOAN SUBGROUPS 333 



gresses in spite of a good appetite. The temperature is often raised to 

 104° to 105.8° F. After a varible time it is noticed that the hind quar- 

 ters are weak, and that the animal drags its legs, the hoofs grazing the 

 ground. These sj-mptons increase and become characteristic, so that 

 when the animal is made t > walk it staggers along, the hind quarters 

 swaying from side to side. On account of this sympton the name liial 

 de caderas, or disease of the hind quarters, has been given to the disease. 

 There comes a time when the animal is unable to stand; if in the stable, 

 it leans up against a wall or seeks other support; if in the open, it stag- 

 gers and falls. After thus falling to the ground an animal may still live 

 for several days if it be fed; otherwise the inevitably fatal end is 

 hastened bj' inanition." 



Infection. — The mode of natural infection is not as yet known. The 

 observed fact that horses separated from affected animals only by a 

 fence remain healthy in spite of the presence of piercing flies, would indi- 

 cate that these insects are not the transmitters. Until something definite 

 is established as to the transmitting agent, no certain preventive meas- 

 ures can be adopted. 



DOURINE 



Dourine is an infectious disease of the horse and ass affecting prima- 

 rily the genital tract. It is due to Trypanosoma equiperdum, transmitted 

 from animal to animal in the act of copulation. The disease is vari- 

 ously^ named "maladie du coit," " el dourine," or " dourine," according 

 to the country in which it is found, dourine, which is from the Arabic for 

 "unclean," being the term most commonly employed for it in the United 

 States. It is supposed to have been introduced into Continental Eu- 

 rope early in the nineteenth century by horses imported for breeding, 

 especially those from the Orient where the disease has long existed. 



In the United States dourine first appeared in Illinois where it was 

 recognized b}^ Dr. W. L. Williams in 1886. The source of the infection 

 was found to be imported Percheron stallion, and it had been dissemi- 

 nated for some time before the true nature of the malady became known. 

 By the application of rigid preventive measures, the disease was eradi- 

 cated from Illinois in 1888, but it had been carried by a stallion to Ne- 

 braska, where an investigation of an outbreak in 1892 by an inspector of 

 the Bureau of Animal Industry revealed that upward of two hundred 

 mares and stallions in the northwestern part of that state were aflfeeted 

 with the disease. Measures taken by the federal authorities brought this 

 outbreak under control for a time, but a few 3'ears later the infection 

 again appeared in the same part of the state. In 1901 there was an out- 

 break in the Pine Ridge and Rosebud Indian Reservations of South 

 Dakota, and in 1903 the disease was reported in Van Buren County, 

 Iowa. It was again found in Taylor County. Iowa, in 1911. Thus dour- 



