Limited advantage of multiple consecutive samples for genotyping Plasmodium falciparum populations during the first days of treatment.

The informative value of genotyping Plasmodium falciparum populations in single blood samples was studied before and during treatment in 13 patients with P. falciparum malaria. Genotyping of the two merozoite surface proteins (msp1 [block 2] and msp2) and the glutamate-rich protein showed multiple genotypes in seven patients, and single genotypes in the remaining six patients. The same genotype profiles were detected in consecutive samples obtained every 12 hours during treatment from the respective patients, although some genotypes were cleared earlier than others. These patterns are in contrast to the extensive daily dynamics previously described in asymptomatic infections. The genotypes detected in one pre-treatment sample thus appear to reflect the parasite subpopulations of the clinical malaria infection during the following days, and additional sampling does not provide any additional information.