METHODS FOR DETECTING SPOROZOITS AND ZYGOTES 

 IN MOSQUITOS INFECTED WITH MALARIA. 



By J. W. W. STEPHENS, M.D. Cantab., D.P.H. 



JVultcr A[ijer.<i Lecturer in Tropical Medicine, Lirerpool School of Tropical 

 Medicine. 



CArXFRE AND PiJELIMINARY PREPARATION OF MOSQUITOS. 



Where to find infected Anophelines. 



(rt.) Select a village or any small collection of native huts where you know, 

 either from a blood examination or from spleen palpation, that the children are 

 infected with malaria. 



(J I.) Anophelines and also Culicines will he found in the huts, near the lire- 

 place, behind curtains, in cupboards, behind clothing, in old boots, collections of 

 bottles, lumber, rubbish of all sorts, and on the thatch of the huts hanging to the 

 sooty straw and cobwebs, often in hundreds. If none can be found, stir the 

 thatch with a stick, as Anoiahelines frequently lie deeply hidden. Examine also 

 out-houses, cowhouses, piles of dried grass in barns, and the outside of mosquito 

 nets before the sun is well up. 



(c.) In short drains or under bridges they may be sometimes caught in 

 hundreds. 



{d.) Or finally, " traps " may be set. These are made out of roomy biscuit 

 tins (lined with felt), with the lid ajar. INIosquitos retreat into these as the sim 

 rises. 



Method of Capture. 



Place a test tube or specimen tube slowly over the Anopheline, and then close 

 it by slipping a plug of cotton wool into the mouth. 



It will save a good deal of time if fifty mosquitos are required, to bring fifty 

 test tubes instead of transferring each one when caught to a bottle. Also the 

 trouble of getting them out of the bottle is avoided. But in case the supply of 

 tubes is insufficient they should be transferred, as caught, into any dry bottle, 

 such as a whisky bottle. There must be no obvious moisture in the bottle, as if 

 there is, the mosquito is caught by its wings and soon dies. 



Identification of Species. 



There is still very little accurate knowledge as to which species actiially do 

 transmit malaria, and also as to which of these are the most concerned. It is 

 essential then to identify, or to get identified, the Anopheline you dissect. A 



(19127—2.) Wt. P352S— 16. 1000. 4/11. D & S. 



