DOURINE 363 
locality, it spread to a considerable number of breeding mares and 
stallions. The disease was verv largely stamped out of that region 
by a rigid quarantine of diseased and exposed animals. Some exposed 
animals had, however, been taken from the district. In 1892, it 
appeared among fhe breeding horses in northwestern Nebraska. 
Five years later it reappeared in the same locality. In 1901, it 
occurred in South Dakota and Nebraska. In 1903, it was reported in 
Iowa and again in 1911. It was discovered in Canada by Burnett in 
1904 and the trypanosome was demonstrated by Watson in 1907. 
In 1912 it was found in Montana. 
Etiology. Rouget, in 1896, described a Trypanosoma found in the 
blood of a horse suffering from dourine, and for over two years con- 
tinued the study of this organism in 
susceptible animals. In 1899 Schneider 
and Buffard demonstrated its causal 
relation to the disease. Wasileswky 
and Senn also confirmed Rouget’s work 
and determined the pathogenic action 
of this Trypanosoma for the horse, pas- 
sing it through other animals and back 
to the horse, reproducing the disease. 
Laveran and Mesnil (1901) proposed 
the name Tr. rougeti for the para- 
site of dourine but Doflein had Fy. 87. trypanosoma oF DOU- 
previously named it Tr. equiper- (he eae OR DIVISION 
dum. 
In its morphology and evolutionary forms, the trypanosoma of 
dourine has not been shown to differ from that of surra by any striking 
character. The granule form, the spherical, the club shaped or 
pyriform bodies, the fusiform with more or less stellate groupings 
seem to be generic characteristics. Baldrey states that it is smaller 
than the trypanosoma of surra. The specific distinction is found in 
the pathogenesis as shown by the two diseases, surra and dourine. 
In the active stages, the parasite is usually found abundantly in 
edematous fluid, the blood, semen, milk, vaginal secretions and. the 
erosions of the vaginal mucosa and penis. During intermissions, 
however, and in the absence of local lesions, the parasites are not 
found in the blood on microscopic examination, yet the inoculation of 
the blood into a dog will usually produce the disease. The parasite 
disappears from the blood and tissues very rapidly after death. 
