

TRANSMISSION OF DISEASES BY INSECTS 269 



tubercle bacilli from fly-specks is unlikely. If mechanically disturbed, 

 infection of the surrounding air may occur." 



If it is true that tuberculosis can be transmitted by means of food, 

 as experiments with some of the lower animals seem to indicate, the 

 house fly is evidently a factor that must be reckoned with in the fight 

 against this disease. 



There is conclusive evidence that Egyptian ophthalmia is trans- 

 mitted by flies and it is highly probable that certain other infections 

 of the eye are conveyed by the same means. 



The bacillus of the deadly disease anthrax can be transmitted by 

 tabanid flies and stable flies, Stomoxys. 



Dr. H. Graham and others have proved that dengue is conveyed by 

 two species of mosquitoes, the common house mosquito of the tropics 

 (Culex quinquefasciatus) and the yellow fever mosquito (A edes argenteus) . 



Phlebotomus fever of Mediterranean regions and India is known to 

 be carried by a sand fly, Phlebotomus; and the peculiar Oroya fever of 

 Peru is possibly transmitted by a fly of the same genus. 



There is partial proof that the destructive kala-azar in India is 

 disseminated by the common Indian bedbug. 



Tropical sore is probably spread by flies of some kind. 



In Ceylon, the skin disease known as yaws is conveyed by the com- 

 mon house fly, Musca domestica; and in the West Indies, probably by 

 common flies of the genera Oscinis and Sarcophaga. 



In 1912 Professor M. J. Rosenau and Dr. C. T. Brues announced 

 that they had succeeded in transmitting infantile paralysis (polio- 

 myelitis) to monkeys by means of the stable fly, Stomoxys calcitrans, 

 and their results were confirmed by Dr. J. F. Anderson. Whether 

 this is the usual means of transmission among human beings it remains 

 to be determined. There is also some experimental evidence that the 

 disease may be carried by the bedbug. 



Rocky Mountain spotted fever was proved by Ricketts in 1906 

 to be conveyed by two or more common species of wood ticks of the 

 genus Dermacentor. 



Smith and Kilborne demonstrated that the destructive Texas fever 

 of cattle, due to a protozoan parasite, is transmitted by a common tick, 

 Margaropus annulatus. The adoption of methods of pasturing that 

 enable cattle to avoid the ticks has been highly successful. 



