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Chapter XXI 

 To MAKE A MALARIAL SURVEY 



ENDEMIC MALARIA 



The clue to the epidemiology of malaria in the 

 tropics is to be found in the infection of the native 

 population of a country. The malaria of Europeans 

 is merely the result of their exposure to infection from 

 this source. Investigation into the natural history 

 of malaria, therefore, resolves itself largely into the 

 study of native or endemic malaria. It has always 

 been recognised that in a particular country certain 

 districts are more malarial than others. It was not, 

 however, till Koch used the percentage of infected 

 children as the test of the malarial intensity of a place 

 that accurate measurement of this became possible. 



To INVESTIGATE THE ENDEMIC MALARIA OF A 

 DISTRICT 



(A) The Breeding-Places of Ano-phelines 



It is the case in India, and almost certainly will be 

 found to be so in other countries, that certain kinds 

 of breeding-places are preferred by certain species.* 

 A collection of larvae made from shallow puddles will 

 be found to yield quite a different set of species to one 

 made from a streamlet or pool full of vegetation, even 

 though close to the puddles (Fig. 68). 



I. Examine all collections of water within half 

 a mile. Stir up the mud of small puddles, and use a 

 dipper where the water is weedy or difficult of access. 

 Examine wells, ' chatties,' streams, and swamps, as 



* Thus M . lutzi is said to breed only in the water collected in the leaves of 

 the parasitic Bromeliaceae, and N. annulipes is said to breed in the sea. 



