[Cross resistance to mefloquine and halofantrine in a case of P. falciparum malaria contracted in Sierra Leone].

Malaria caused by P. falciparum occurred during prophylaxis with mefloquine upon return from Sierra Leone (zone II). A typical and not recognized, with negative results of initial hematological examinations. Diagnosed on D.26 with parasitemia of 0.2%. Successful treatment of clinical symptoms with halofantrine but increased anemia and positive parasitemia at D.7. Successful treatment with chloroquine. Chemosensitivity tests confirmed sensitivity to chloroquine, threshold sensitivity to quinine (IC50 = 297), resistance to mefloquine (IC50 = 76) despite high levels in bloods, and to halofantrine (IC50 = 7-laboratory normal value = 1). This cross-resistance of P. falciparum originating from Sierra Leone to mefloquine-halofantrine seems to be the first observation of this danger in Africa. Prescription of chloroquine is still imperative in zone 11 countries.