[Surveillance of the in vivo sensitivity of Plasmodium falciparum to antimalarial agents: the results of initial tests of the OCEAC Malaria Network].

The Malaria Control Division of the Organization for Endemic Disease Control in Central Africa (OCEAC) has developed a standardized method to measure the in vivo sensitivity of Plasmodium falciparum to antimalarial drugs. Between May 1996 and February 1997, a first series of tests using this method was carried out to determine the sensitivity of Plasmodium falciparum to chloroquine and amodiaquine in infected school children in four capital cities: Yaoundé, Brazzaville, Malabo, and Libreville. As expected, only children presenting more than 100 parasites per 1000 leucocytes were enrolled. Results showed variable degrees of in vivo resistance to chloroquine and amodiaquine at each location: 25% and 13% respectively in Yaoundé, 19% and 11% in Malabo, 23% and 43% in Brazzaville, and 29% and 0% in Libreville. Overall results concerning chloroquine of this test series were similar to recent data in comparable populations and confirmed the idea that the situation has stabilized in Central Africa. Findings concerning amodiaquine raise the need for further study to validate and explain the contrasting findings in Libreville (0%) and Brazzaville (43%). This first experience shows that the method is simple and quick and that it can be used with minimal means. Results could provide important early warning data for national health officials.