EVIDENCE THAT RECURRENT PLASMODIUM-FALCIPARUM INFECTION IS CAUSED BY RECRUDESCENCE OF RESISTANT PARASITES

Isolates of Plasmodium falciparum obtained from 12 children attending different health facilities in the Madang Province, Papua NEW Guinea w ere typed for allelic variants of merozoite surface protein-1 and mero zoite surface protein-2. Blood was obtained just before treatment with either amodiaquine or chloroquine and at intervals following treatmen t. All patients examined were found to be infected with genetically di fferent parasites. Nine of the children were found to have single infe ctions while three had mixed infections. In all patients, parasites re appearing in the blood following treatment had the same genotype as pa rasites in the primary infection. These results indicate that parasite s reappearing in the blood following treatment were the result of true recrudescence and not new infections.