Between 1978 and 1988 Plasmodium falciparum resistance to
chloroquine has been reported in all countries of tropical Africa. Despite the intensification of resistance during the last 2 decades,
chloroquine remains in 2000 the first-line treatment for
malaria in most of these countries. Here we review published data on the public health impact of
antimalarial drug resistance in Africa. These data show that since the late 1980s convincing evidence of a major public health impact of the spread of
chloroquine resistance has been available. Hospital studies in various African countries have documented a 2- or 3-fold increase in
malaria deaths and admissions for severe
malaria, an increase temporally related to the emergence of
chloroquine resistance. Data from sentinel demographic surveillance systems in Senegal indicated that mortality attributable to
malaria in children increased by as much as 6-fold among populations where low levels of
malaria mortality had been achieved because of efficient health services before the emergence of
chloroquine resistance. Increasing incidence of severe malarial
anemia also contributed to human immunodeficiency virus dissemination. The dramatic impact of
chloroquine resistance on
malaria mortality has long been underestimated because only a low proportion of
malaria attacks are potentially lethal among persons continuously exposed since birth to high levels of transmission. There is an urgent need to change treatment policies in Africa.