Are Plasmodium falciparum parasites present in peripheral blood genetically the same as those sequestered in the tissues?

Abstract

Since quinine does not inhibit the growth of Plasmodium falciparum ring stages or mature schizonts, parasites may continue to emerge from sequestration sites after starting treatment. We used polymerase chain reaction amplification of P. falciparum merozoite surface protein 1 (MSP-1) and MSP-2 alleles to distinguish genotypes infecting 58 children with severe malaria. To examine changes in parasite populations in peripheral blood over time, we compared changes in number and spectrum of genotypes in samples on admission to a hospital to those obtained up to 24 hours later. Thirty-four children lost genotypes, 21 retained genotypes, and 3 gained an extra P. falciparum genotype at one locus but not the other. The lack of novel genotypes emerging suggests that among children with severe malaria the dominant clones sequestered in deep organs are usually the same as those in peripheral circulation. Copyright © 2006 by The American Society of Tropical Medicine and Hygiene.