82 REPORT OF THE AGRICULTURAL RESEARCH INSTITUTE 



Surra Investigation. 



Mr. Patel visited Kathgodam and Bareiliy in Septem- 

 ber-December 1915, to ascertain what kinds of biting flies* 

 were prevalent in the Surra Zone and to carry out trans- 

 mission experiments. A full account of these has been sent 

 to the Imperial Bacteriologist, who will (I understand) 

 publish them with his own results; it is therefore only 

 necessary to give here a short summary of the results 

 attained, viz. : — 



(1) Tabanus albimedius and T. striatus were found 



capable of transmitting the Surra organism, not 

 only by an interrupted feeding, but also by com- 

 plete feeding. 



(2) Tabanus albimedius was proved to transmit Surra 



24 hours after feeding on Surra-infected animal; 

 it failed to transmit disease after a longer inter- 

 val. T . striatus, however, was found capable of 

 transmitting Surra (in one experiment with two 

 flies) as long as 72 hours after feeding on an 

 infected host. 



(3) Smaller species of Tabanus (T . sp. near virgo) were 



tried but not found to transmit disease. 



(4) Ctenocephalus felis, dog and cattle fleas, were 



found incapable of transmitting Surra. 



(5) Philcematomyia insignis is only capable of trans- 



mitting Surra in the case of an immediate 

 interrupted feeding, the maximum interval {i.e., 

 between leaving an infected host and commenc- 

 ing to feed on a previously uninfected animal), 

 for which positive results were obtained, being 

 only seven minutes, although positive results 

 were obtained by direct inoculation of abdo- 

 minal contents of infected flies as long as 28 

 hours after feeding on a Surra-infested animal. 



(6) Surra is not transmitted hereditarily to the 



progeny of infected females of Tabanus stria- 

 tus, T. albimedius, or Philoematomyia insignis 



