Declining chloroquine resistance of Plasmodium falciparum in Lambarene, Gabon from 1992 to 1998

Plasmodium falciparum malaria continues to threaten human populations in th e tropics and travellers in endemic areas. Drug resistance of the parasite is a major problem in treating this devastating disease. In a prospective trial we investigated the in vitro sensitivity of Plasmodi um falciparum to chloroquine, quinine and mefloquine in the Albert Schweitz er Hospital in Lambarene, Gabon every second year from 1992 to 1998. We use d the standard WHO in vitro sensitivity assay. Parasite sensitivity to quinine and mefloquine remained stable over the yea rs. However, parasite resistance to chloroquine decreased highly significan tly with the change in local malaria treatment policy. In 1992, 100% of par asite isolates showed resistance to chloroquine, whereas in 1998 only 45% w ere found resistant.