INFECTIOUS DISEASES 265 



SURRA. 



Synonyms. Relapsing fever of equines ; pernicious anae- 

 mia of horses. 



§ ig6. Characterization. Surra is an infectious disease 

 of solipeds and camels caused by a flagellate protozoon. It is 

 determined by a continuous fever with alternate paroxysms 

 and intermissions, with a general or localized eruption of the 

 skin, petechiae of the mucosae and more or less subcutaneous 

 oedema. There is rapid emaciation and great weakness. It is 

 usually fatal. It attacks horses, asses, mules, goats, dogs, 

 cattle and rats. It can be inoculated into other animals such 

 as rabbits and guinea pigs. From an economic point of view it 

 is reported to be essentially a disease of horses. 



§ 197. 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 northwest frontier of India. Haig appears to 

 have observed it in Persia in 1876. In 1880, Evans found sev- 

 eral cases of it in the Dera Ismael Khan country. 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 Evan's 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 epizootic in 

 Bombay. 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 1S95 are reported to be appalling. 



§ ig8. 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 the 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 the t.se-tse 

 fly disease is accepted, as it seems to be, it has a wide dis- 

 tribution in Central Africa. • 



Surra does not exist in the United States, but because of 

 its prevalence and long standing in the Philippines it is liable 



