Parasitemia in children with Plasmodium falciparum malaria recerving chemoprophylaxis

Among 36 nonimmune children hospitalized in Paris for acute Plasmodium falciparum malaria after travel in Africa, 12 had received regular prophylaxis with chloroquine and proguanil until hospitalization, 16 had taken prophylaxis irregularly and 8 had received no prophylaxis. All had high fever and common symptoms of acute malaria. In patients who received regular prophylaxis, 4 of 8 had low levels of parasitemia (< 5 trophozoites/mul), and mean parasitemia was 32 trophozoites/mul (range, 1 to 190). Only 2 of 34 in the other 2 groups have values < 5 trophozoites/mul, mean parasitemia being 105.1 and 142.8 trophozoites/mul, respectively (P < 0.05; range, 1 to 525). The diagnosis of malaria could easily be missed in patients with fever and low levels of parasitemia because of chemoprophylaxis.