THE TRYPANOSOME OF DOURINE 809 



2. Trypanosoma equiperdum (Doflein). 

 Trypanosome of Dourine. 1 

 8301. Trypanosoma rougeti. 



The trypanosome of dourine was discovered in Constantinople by Rouget, 

 in the blood of a stallion affected with mal du coit. It has been studied more 

 recently by Schneider and Buffard. 



Horse syphilis is transmitted by the act of coitus, perhaps also by fleas (Rabino- 

 witch and Kempner, Sieber and Gonder). In the first stage of the disease in the 

 stallion there is oedema of the penis, scrotum and inguinal regions ; in the mare this 

 painless oedema affects the vulva and vagina and leads to a more or less abundant 

 mucous secretion. In the second stage about a month after coitus characteristic 

 infiltrated firm plaques appear, affecting the sub-cutaneous tissue covering the ribs, 

 the crupper and sometimes the neck, shoulders and thighs. Finally, in the third 

 stage, extreme anaemia, paralysis and sometimes epileptiform attacks appear. 

 Recovery is exceptional and when it does occur is as a rule merely apparent, the 

 animal soon suffering a relapse. 



Morphology. The trypanosome of dour- 

 ine is fusiform in shape and measures about 

 25-28/A long by 2/x broad in the centre. Its 

 protoplasm stains uniformly blue by La- 

 veran's method and contains no chromatin 

 granules. The nucleus is distinctly cen- 

 trally situated. There is a folded un- 

 dulating membrane the free border of 

 which terminates anteriorly in the flagellum 

 and is lost posteriorly in the centrosome. 

 It is distinctly less motile than T. lewisi 

 but nevertheless shows obvious movements 

 of translation : the motility is still apparent 

 after about 18 hours in preparations of 

 fresh blood. 



Reproduction appears to take place in FlG - 

 the same way as in T. lewisi ; binary longi- 

 tudinal fission is the method most frequently seen. Forms with 8 to 10 

 nuclei developing into a sort of rosette have been recorded (Laveran, Rabino- 

 witch, Kempner). 



Cultures. All attempts to grow Trypanosoma equiperdum outside the body 

 in the blood of susceptible animals have failed (Rouget) : in such blood the 

 parasite loses its virulence in less than 24 hours. 



Experimental inoculation. Cold-blooded animals, birds, cattle, monkeys 

 and guinea-pigs are immune. 



Mice, white rats, rabbits, dogs, horses and mules are all susceptible to 

 infection. 



In determining the susceptibility of a given animal to the parasite it is necessary 

 to take into account the adaptation which the parasite undergoes as a result of 

 repeated passages through a given species (Nocard). Rouget experimenting with 

 rats and mice recovered a parasite which proved to be very virulent for these animals. 

 Schneider and Buffard after several passages through dogs recovered a trypanosome 

 which was harmless for mice and rats ; this trypanosome was inoculated by Nocard 

 into the brain of a young rat, which it infected, and it was then found to be virulent 

 for adult rats. 



1 [Dourine, Horse syphilis, or Mal du coit is a disease of horses occurring in Europe, 

 North America, Algeria and India. ] 



