Steep Rebound of Chloroquine-Sensitive Plasmodium falciparum in Zimbabwe

Abstract Removal of chloroquine from national malaria formularies can lead to the reversion of resistant Plasmodium falciparum to wild-type. We report a steep decline in chloroquine-resistant P falciparum within 10 years of national discontinuation of chloroquine monotherapy in Zimbabwe. Drug resistance surveillance is a vital component of malaria control programs, and the experience with chloroquine in Zimbabwe and elsewhere in sub-Saharan Africa is illustrative of the potentially rapid and dramatic impact of drug policy on antimalarial resistance. Within 10 years after national discontinuation of chloroquine monotherapy for Plasmodium falciparum malaria in Zimbabwe, the frequency of chloroquine resistance declined from 67% to 3% and was undetected 5 years later.