15 



Mosquito Work i.\ Khartoum and in the .VxaLo-ErrYPTiAN 



Sudan Generally 



111 tlie First Report of these Laboratories an account was given of the starting of a 

 mosquito brigade, and of its operations. 



It was shown that 50 per cent, of the total water collections in Khartoum were found 

 to be infected, and that six months' work reduced this number to 9"5 per cent., and in 

 adtlition caused the disappearance of Anopheliues, and a great lessening in the number of 

 Stegomyia. 



These results were so encouraging that it was decided to continue the brigade, and to 

 bring Khartoum North into the sphere of operations. This was done in March, 1904, and 'n'^r'^ase m 

 I am now able to give a nearly complete list of statistics of mosquito reduction for operations 

 Khartoum and Khartoum North. As previously pointed out these figures make no pretence 

 at absolute accuracy, but they closely approach the truth. 



The term water collection is a somewhat arbitrary one. It includes all wells holding Definition of 

 water in which mosquitoes might breed, rain-pools of sufficient size or depth to remain for a | '■"^■^'^ 

 period of at least one week, similar pools left by the falling Nile, the syphon pits of collection" 

 irrigation channels, or pools formed by leaking channels, permanent garden pools or ponds, 

 and bath waste-pits. 



Zeers, fire-buckets holding water, and similar cuUectiuus which cannot be regarded as 

 permanent, are not counted in the monthly returns unless found infected. 



This method is about the most satisfactory that can be devised, and gives a fairly 

 definite basis on which to work. 



Collections in boats, barges and steamers are not included in these returns, though 

 statistics are kept about them for purposes of reference.* 



MOSQUITO statistics— KHARTOUM, 1904-1905. 

 Continuation from First Repobt. 



Statistics, 

 Khartoum 



• In the tables A signifies Anophelines, C, Culices and S, Stegomyiae. 



