Malaria N° 7 - Subject N° 6

PLASMODIUM FALCIPARUM CHEMORESISTANCE IN THE CONGO RESULTS OF A SURVEY CONDUCTED IN BRAZZAVILLE IN 1996
B. Carme, M. Ndounga, A.M. Kissila, A. Mbitsi, G. Samba & B. Tsika

SUMMARY
No significant variation, both in vivo and in vitro, in the degree and level of Plasmodium falciparum chloroquine resistance (CQR) was seen following technically controlled surveys carried out in comparable populations in Brazzaville between 1986-87, 1990, 1993 and 1996. In the capital of the Congo, the level of CQR remained moderate in 1996 even though the percentage of semi-immune children, still parasitaemic but asymptomatic at D7, was relatively high (simplified in vivo test, 25 mg/kg in divided doses over 3 days). Indeed, no case of R3 type resistance was found in 46 tests; the parasitic loads (Pf/ml) at D7 and particularly from D2 onwards were low.
Quinine retained good in vivo efficacy (25 mg/kg/day) though one strain out of five however had a relatively high IC50 according to the in vitro maturation test used; there has been no significant variation since 1990. The absence of a correlation between the IC50, the mean defervescence time and the lack of a parasitaemia during the first three days of treatment is is worth noting.
Plasmodium falciparum remains very sensitive to halofantrine in vitro.

KEY WORDS: Malaria, P. falciparum, Chemoresistance, Chloroquine, Quinine, Halofantrine, In vivo tests, In vitro tests, Congo