TRYPANOSOMA EQUIPERDUM 97 



American rodent, the capybara (Hydrochcvnis capybara). This animal 

 appears to be a reservoir of the parasite. Dogs may become infected 

 by eating diseased capybaras, and it is suggested that the infection is 

 spread from the dogs to horses by the agency of fleas. Some authorities 

 consider that T. equinum may be spread by various Tabanidce and by 

 Stomoxys. Neiva (1913) x doubts, all these modes of transmission in 

 Brazil, and suggests Chrysops or Triatoma as vectors. 



Trypanosoma equiperdum, Doflein, 1901. 

 Syn. : Trypanosoma rougeti^ Laveran and Mesnil. 



The malady of horses known as " dourine " or " mal du co'it " is 

 due to a trypanosome, T. equiperdum, discovered by Rouget in 1894. 

 "Dourine" also known as " stallion disease" or "covering disease" 

 is found among horses and asses in Europe, 

 India, North Africa and North America. The 

 trypanosome is transmitted by coitus, and so 

 far as is known not by insect agency. 



The progress of the disease may be con- 

 sidered under three periods. The period of 

 cedetna, when signs of oedema of the genitalia 

 are seen. The oedema is generally painless 

 and non-inflammatory. This period lasts about 

 a month. It is succeeded by the period of 

 eruption, which sets in about two months 

 after infection. Circular cedematous areas 

 (" plaques "), often about the size of a two- FIG. 43. Trypanosoma 

 shilling piece, appear under the skin of the sides equip'rdum. x 2 oooapprox- 



imately. (Original. From 



and hind quarters, and also, at times, under the preparation by Fantham.) 

 skin of the neck, thighs and shoulders. The 



eruption is variable, but usually lasts about a week and leaves the 

 animal in an enfeebled condition. Gland enlargement and swelling 

 of the joints and synovia also may occur. The third period of the 

 disease is described as that of aucemia and paralysis. The animal 

 becomes very anaemic, emaciation is marked, superficial non-healing 

 abscesses often form, and conjunctivitis and ulcerative keratitis can 

 occur. Paralysis ensues, and in from two to eighteen months the 

 animal dies. In the acute form of the disease the animal may die 

 after the first period from acute paralysis. 



It is difficult to find the trypanosomes in naturally infected 

 animals, and they are best obtained from the plaques of the 

 eruption. Apparently the parasite occurs more in the lymph than 

 in the blood. 



1 Brazil Medico, xxvii, p. 366. 



