SURRA 373 
SURRA 
Synonyms. Relapsing fever of equines; pernicious anemia of 
horses. 
Characterization. Surra is an infect’ous disease of solipeds, 
camels and cattle caused by a flagellate protozoan. It is determined 
by a continuous fever with alternate paroxysms and intermissions, 
with a general or localized eruption of the skin, petechie of the 
mucose and more or less subcutaneous edema. There is rapid 
emaciation and great weakness. It is usually fatal. It can be 
inoculated into other animals such as dogs, rats, rabbits, guinea pigs 
and mice. From an economic point of view it is reported to be essen- 
tially a disease of horses. 
In India, cattle are said to be infected with the trypanosomes of 
surra but they are not appreciably affected by them. It is reported 
that horses become infected by insects that have first bitten such 
cattle. 
History. This disease appears to have been known for many years 
to the natives of the low lands on both sides of the Indus on the north- 
west frontier of India. Haig appears to have observed it in Persia in 
1876. In 1880, Evans found several cases of it in the Dera Ismael 
Khan county. He was the first to describe it and attribute its cause 
to an animal parasite which he discovered in the blood. In 1885, 
Steel met with a disease among mules in Burma which he regarded as 
identical with Evans’ surra, and which he believed to be relapsing 
fever. In 1888, there was an outbreak among the Bombay Tramway 
Company’s horses. Since then surra has become epizodtic in Bom- 
bay; Lingard reports that thousands of ponies, horses, camels and 
asses died from it during the rains of 1893 and 1894. Its ravages in 
the Punjab and Northwest Provinces during 1895 are reported to be 
appalling. 
Geographical distribution. It is a disease of Asia and Africa. It 
is reported that “the distribution of this malady seems to be entirely 
influenced by the physical aspect of this country; being far more 
prevalent in those parts where floods and inundations occur than in 
the higher and dryer portions” (Pease). If the identity of surra with 
tsétsé-fly disease proves to be true, which is still questioned, it has a 
wide distribution in Central Africa. 
Surra does not exist in the United States, but because of its preval- 
ence and long standing in the Philippines it is liable to be introduced 
