284 THE DISSEMIXATIOX OF OTHER DISEASES BY FLIES 



conclusive to warrant the conclusion that, under the conditions 

 indicated by Leboeuf, namely, abundance of flies, proximity of 

 leprous ulcers or infected discharges and exposed places for in- 

 fection on healthy persons, house-flies are able to transmit the 

 leprous bacillus. 



Dysentery. 



It would appear to be not improbable that flies, in view of 

 their relation to typhoid fever, should sometimes be agents in 

 the spread of dysentery. The etiology of this disease has been 

 a matter of considerable controversy but it is generally accepted 

 now that in the bacillary type of the disease one of the causative 

 organisms is B. dysenteriae, these organisms being regarded as the 

 cause of epidemic dysentery, while in the sporadic or endemic 

 dysentery, usually known as amoebic dysentery, the causative 

 organism belongs to the Amoeba gi'oup of protozoa, of which 

 there are probably several species. The possibility of flies carrying 

 the infection of both types of disease appears to me to be highly 

 probable, especially in the amoebic type of the disease. The 

 amoebae multiply on the intestine by fission and are passed out 

 with the faeces. When the faeces become hard the amoebae 

 encyst. It is not unreasonable to suggest in view of positive 

 evidence in other cases of a similar nature, that flies bred in or 

 feeding upon infected faeces, might ingest the amoebic cysts and 

 with these infect food. 



Unfortunately we have no exact evidence as to flies carrying 

 dysenteric infection. Smith (1903) states : " An old idea of some 

 Anglo-Indian surgeons was that dysentery could be caught by 

 using the same latrine as a dysentery patient. There may be 

 something in this... the ubiquitous fly may, therefore, be a 

 dysentery inoculator in open camp latrines." While such in- 

 oculation is not unlikely, the probability of flies infected in the 

 latrine visiting food or patients in the hospital is greater. The 

 possibility of flies playing in dysentery a similar part to that 

 Avhich they do in typhoid and cholera is refen-ed to by Bergey 

 (1907). An epidemic of one hundred and thirty-six cases of 

 dysentery which occurred in an insane asylum at Worcester, 



