STATE HYGIENE 609 



The incubative period is about twenty-one days ; one 

 attack probably gives immunity. Eecovery is frequent in 

 cases treated early, otherwise it is very fatal. The preven- 

 tive treatment is not to expose horses foreign to the 

 country to infected pastures, and to keep them free from 

 ticks. It is to Theiler that we are indebted for a clear 

 account of the disease and the discovery of the parasite.* 



Pyroplasmosis of the donkey has been described by 

 Dale.t In the donkey there is no jaundiced condition as 

 in the horse, though the parasite (also discovered by 

 Theiler) is very like that of the horse and mule, if not 

 identical with it. The disease is amenable to treatment. 



EPIZOOTIC DISEASES DUE TO TEYPANOSOMATA. 



Surra — Tse-tse — Maladie de Co'it — Gall-Sickness — 

 Mai de Caderas — Gambian Horse Disease. 



These diseases are due to a trypanosome in the blood of 

 animals, and in all but one case, noted below, it is probable 

 that a blood- sucking insect is the means of infection. No 

 practicable means of prevention is known, protection from 

 fly attacks by avoiding those districts known to be affected 

 is at present the only thing to be done. 



Something may, however, be done to prevent a country 

 becoming infected, by the quarantine of all animals from 

 affected countries and the examination of their blood. 

 Should the disease find its way in, destruction of all affected 

 is the only course to pursue. In this way the Dutch 

 stamped out ' Surra ' in Java. 



Surra particularly affects horses, though cattle and dogs 

 are known to be attacked. In cattle it is a benign 

 disease. In Tse-tse disease, horses, cattle, and dogs are all 

 equally affected, and in each equally fatal. Dourine or 

 maladie de edit is essentially a disease of equines, and con- 

 veyed under ordinary circumstances exclusively by sexual 



* Journal of Comparative PatJwlogy, vol. xv., 1902. 

 t Idem, vol. xvi. , 1903. 



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