Low gametocyte thresholds of infection of anopheles with plasmodium falciparum

Abstract

Observations in Gold Co,ast villages where malaria is hyperendemic have confirmed previous findings in Jamaica, and by American workers in South Carolina, that some carriers can infect anopheles with P. falciparum at a time when the density of gametocytes in the blood is so low that they may be detected only with difficulty in routine blood-film examination. In the Gold Coast experiments these cryptic carriers formed a significant proportion-roughly one-quarter of all infective carriers. This finding, together with the fact that many good crescent carriers are non-infective to mosquitoes, suggests that the blood-film examination may prove a very deceptive guide to the real malaria infectors in the African or native village community. The implications of these findings are discussed in the light of recent work on the uneven distribution of anopheles bites and feeds among different human age groups. © 1954, British Medical Journal Publishing Group. All rights reserved.