XXI] LYPEROSIA AND DISEASE 371 



LYPEROSIA and Disease 



There is no direct experimental evidence in support 

 of the view that Lyperosia carries any infection, but certain 

 authors have suggested that this fly may occasionally 

 be responsible for the spread of various trypanosomiases 

 of animals. Schat is of the opinion that Lyperosia exigua 

 de Meijere, takes a part in the spread of Surra in Java. 

 Montgomery and Kinghorn, in Rhodesia, record an outbreak 

 of trypanosomiasis occurring under the following circumstances. 

 A herd of cattle in Northern Rhodesia which had been in good 

 health for a year was kept on a farm two-and-a-half miles 

 from the nearest tsetse area. In April six bullocks were sent 

 on a journey and as they passed through a fly belt were prob- 

 ably bitten by tsetse. These bullocks returned to the farm a 

 few days later. In June, three of these animals and also one 

 which had not been away shewed trypanosomes. In July, 

 fifteen animals were infected so all the healthy cattle were 

 isolated in a place that seemed free from biting-flies. Five 

 more of these animals shewed trypanosomes in August and were 

 removed, but the balance continued to remain uninfected. 

 The average duration of the disease was about 30 days, and the 

 parasite is described as T. dimorphon. The authors write : 



" From an examination of all conditions, we think it prob- 

 able that one or more of the six cattle that went to Mwomboshi 

 in April contracted the disease on the road and brought it to 

 the farm, where, in the presence of Stomoxys and Lyperosia in 

 the kraals, the animals, including cows and bulls, which did 

 not leave the place, became infected, and that the segregation 

 from these flies checked its spread to the fourteen cattle which 

 remained healthy." Montgomery and Kinghorn believe that in 

 this case, Lyperosia was partly responsible for the transmission, 

 the trypanosomes being directly carried from infected to healthy 

 animals. 



In India, Leese has given an interesting account of an out- 

 break of Surra in the Bikanir State in the desert of Rajputana. 

 During this outbreak the Imperial Service Camel Corps, out of 

 500 camels, had only 205 survivors and of these 130 were 



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