Surra : Rot. 585 



Definition. An acute, relapsing, protozoan fever of equines, 

 camels and elephants, inoculable on other animals, occurring 

 during or after the rainy season, and characterized by hyper- 

 thermia which is liable to be intermittent, remittent or relapsing, 

 anasarcous swellings, petechias of the mucosae, icterus, cutaneous 

 eruption, nasal, ophthalmic, vaginal and other mucous dis- 

 charges, rapidly advancing ansemia, emaciation and debility, and 

 above all, by the presence in the blood, at intervals from one to 

 six days, of swarms of protozoa, analogous to those found in 

 dourine or nagana. 



Geographical Distribution . Surra has long been known to the 

 English veterinarians in India, occurring during or just after the 

 rainy season, and especially on the low flooded lands, along 

 canals, rivers, lakes, etc., and later in Burma, Cochin China, the 

 Persian Gulf, Persia. I,ingard claims its existence in East 

 Africa, North and South America, Australia and Southern 

 Europe, but he has evidently confounded it with nagana and 

 other affections. The discovery of the disease by Dr. Slee in 

 1901, among American, Australian and Chinese ponies in the 

 Philippines is suggestive of a very wide diffusion of the infection 

 in Southern A,sia and adjacent islands, with which an American 

 work on veterinary medicine must dtal. 



Cause. Parasite. Trypanosoma Evansi. The essential cau.se 

 of the disease, Trypano.soma Evansi, discovered by Dr. Griffith 

 Evans, Inspecting Veterinary Surgeon, British Army, in 1880, 

 is a flagellate infusoriau, pointed at one end, iiear which is a 

 dark centrosome, and from this a flagellum running along the 

 free border of the broad undulating membrane to the extreme op- 

 posite end of the parasite and extended beyond this as a waving 

 la.sh. The length of the Trypanosoma Evansi is 20 to 50/*, (10 

 to 14/1, Smith and Kinyoun, Manila), its breadth i to 1.5/1. By 

 reason of its large size and active motion it is ea.sily detected in 

 a film of fre.sh blood under J^th inch objective, and no less easily 

 when dried and .stained on a cover glass. It must be borne in 

 mind that the mature parasite appears in the blood at intervals 

 in swarms, so that examination at one time of day, or on a par- 

 ticular day, may fail to detect it, while examinations made earlier 

 or later are successful. The general .structure and successive 



