DISEASES BORNE BY NON-BITING FLIES 119 



Mastigophora: Binucleata: Trypanosomidae 



< Castellanella evansi (Steel) Chalmers (Trypanosoma) -, the cause of 

 I SURRA, an African disease of horses and other mammals, may be carried 

 by Musca domestica by contact with wounds. 



CasteUanella hippicum (Darling) Chalmers {Trypanosoma)^- the 

 cause of MURRINA, a disease of horses and mules in the United States 

 and Panama, may be carried according to Darling (1911, 1912) by Musca 

 domestica, Chrysom3'a and Sarcophaga, from wounds by mechanical 

 transmission. He ascertained that the trypanosomes remained alive in 

 the proboscis of the fly at least two hours, and he also successfully inocu- 

 lated a mouse with the crushed portions of a proboscis of a fly which had 

 fed on infected blood. Isolation of tlie animals from fl}' attack, and bind- 

 ing up of wounds wiped out the epidemic. He did not ascertain whether 

 the trypanosome might pass out of the fly's feces and contaminate lesions 

 in this manner, which naturally is the normal method of fly transmission. 



Mastigophora: Spirochaetacea: Spirochaetidae 



Treponema pertenue (Castellani), the cause of YAWS, an infectious 

 disease of men, may be transmitted by the house fly, Musca domestica. 

 Castellani in Ceylon (1907) found that flies eagerly crowd around the 

 open sores of yaws patients. In the hospitals as soon as the dressings 

 were removed from the yaws ulcerations, they became covered with flies, 

 sucking with avidity the secretion, which they may afterward deposit in 

 the same way on ordinary ulcers on other people. He conducted experi- 

 ments which proved that the flies do take up the organism, which he recov- 

 ered from the dissected mouth parts. He fed flies on the organism, then 

 removed their appendages and fastened them over scarified areas of skin 

 of monkeys, and obtained in two experiments positive lesions by this 

 organism. Robertson (1908) also definitely obtained this spirochaete 

 from flies collected on yaws lesions. Nicholls (1912) ascribes most of the 

 cases of yaws in the West Indies to inoculation of surface injuries by 

 Oscinis pallipes Loew. Sarcophaga is also considered a carrier. None 

 of the experiments have been directed at obtaining infection through the 

 deposition of the spirochaetes, taken up by the fly in feeding, in its feces 

 on other ulcers or injuries. This would appear to be the most likely 

 method of infection. 



^ The classification of the Trypanosomes has recently been modified by Chalmers, 

 including several genera composed of species with similar morphological and bio- 

 logical characteristics. 



