832 Dourine. 



As the ring and semi-circular dollar spots have been ob- 

 served in northern regions only in dourine, they may be con- 

 sidered as characteristic for the disease, or at least accepted 

 as suspicious in a high degree. Their repeated appearance 

 for weeks and months, and frequently also their persistence 

 for several days, distinguish them from the ordinary urticaria. 



In tropical regions the differentiation of dourine from 

 nagana, surra and Mai de caderas may evidently cause diffi- 

 culty, but as according to the reports so far available, trypano- 

 somes in the secretions of the genital organs are found only 

 in dourine, their presence there would clear the diagnosis ; like- 

 wise an infection which may be shown to have been trans- 

 mitted by coitus speaks for dourine. 



Fig. 149. Vaginal secretion of a mare affected with dourine. a trypanosomes ; 6 

 epithelial cells from the deeper, d from the superficial layer of the mucous membrane ; 

 c leucocytes ; e erythrocytes. After a fresh, unstained preparation. 



According to Baldrey the disease may be distinguished from surra 

 in that the latter usually occurs in epizootics, geldings and unbred mares 

 become affected, the body temperatures reach high degrees and last 

 longer, and trypanosomes are present in the blood in great numbers at 

 the beginning of the fever. According to Davison, Bursattee (see p. 

 -739) also resembles dourine as it also is associated with a swelling of 

 the genitals and inflammation of the skin; these however are very 

 painful. 



At times where there exists no suspicion of infection, the 

 initial stage of dourine is sometimes mistaken for a traumatic 

 jiilammation of the genitals ; however, the traumatic origin may 



