Atabrine suppression is not only important in suppressing individual attacks of malaria, but it has a dampening effect on the development of epidemic malaria in troops. This is demonstrable since the malaria rate in troops, the gametocyte rate in troops, and the infection rate in mosquitoes vary in direct relation to one another. Thus adequate atabrine suppression in large numbers of men prevents many infections that would otherwise take place.
Studies on two divisions during and after combat illustrate the thesis. The studies include determination of stabrine levels, thick smear surveys, mosquito dissections and malaria surveys.
The routine administration of plasmochin in acute attacks of malaria is found of little practical value in preventing transmission among troops under suppression. None of four carriers picked up on routine surveys had been treated for malaria previously. The symptomless development of the carrier state under atabrine suppression was demonstrated in one case.
Although atabrine suppression so depresses the total malaria rate that this is no indication of recent transmission, it is possible during imperfect suppression to follow transmission by following the ratio of falciparum to vivax malaria.