Complexity of plasmodium falciparum clinical samples from Uganda during short-term culture.

Abstract

We cultured Plasmodium falciparum parasites from 98 Ugandan children with malaria and determined the complexity of infection (COI) on the basis of msp-2 polymorphisms daily for 9 days. The mean COI decreased during culture from 1.73 to 1.56. New strains appeared after day 0 in 20 cultures. Strains disappeared after day 0 in56%of 45 cultures that were initially mixed; persisting strains more commonly had wild-type dhfr (C59) and dhps (K540) sequences and mutant pfmdr1 (86Y) sequences. Thus, initial genotypes offer an imperfect representation of clinical COI. Loss of strains in culture may be due to diminished fitness of some drug-resistant strains.