871 



THE IMPORTANCE OF BLOOD-SUCKING FLIES AS 



TRANSMITTERS OF DISEASE TO MAN 



AND ANIMALS. 



BY 



Lieut.-Colonel W. B. Bannekman, M.D., B.Sc., I. M.S., 



Director, Bombay Bacteriological Laboratory. 



{Read before the Bombay Natural History Society 

 on the 13th December 1906.) 



The importance of knowing something about biting flies is manifest 

 when one realises that many tropical diseases are conveyed from one 

 man to another, and one beast to another by means of their bites. For 

 instance, it has been common knowledge since the days of David 

 Livingstone that in Africa a destructive disease among horses and cattle 

 was due to the bites of the Tsetse-fly (Glossina morsitans). A few 

 years ago Colonel David Bruce, R.A.M.C., discovered the cause of 

 this disease to be a parasite [Trypanosoma brucei) living in the animal 

 which parasite was sucked up by the Tsetse-fly along with its meal of 

 blood, and transferred by it to the body of the next animal it attacked. 

 This parasite belongs to the Protozoa, the lowest order in the animal 

 kingdom, and lives in the blood of the wild game in South Africa. In 

 them it appears to cause no disease, but when transplanted by means of 

 the biting fly to domestic animals it produces a fatal disease, which 

 becomes so prevalent that it was found impossible to keep farm stock in 

 the affected regions until all the wild game, which acted the part of 

 reservoirs of the parasite, had been destroyed. Later still the same 

 observer found that a parasite, in all respects similar to this Tsetse-flv 

 protozoon, was the cause of the fatal disease of human beings in 

 Uganda known as Sleeping Sickness. In the blood of patients suffer- 

 ing from this disease exists a minute eel-like organism {Trypanosoma 

 gambiense) furnished with a fin-like membrane along the back and a 

 flagellum in front, which ultimately makes its way into the cerebro- 

 spinal fluid and produces the well known symptoms of this terrible 

 disease. It has been discovered that the trypanosome is taken up by a 

 Tsetse-fly {Glossina palpalis) as it sucks the blood of a patient, and 

 that it then may be transferred by the fly to the blood of a healthy 

 individual should such happen to be bitten by it within a shoit time 

 afterwards. It was further discovered that Sleeping Sickness was 



