Microsatellite Characterization of Plasmodium falciparum from Cerebral and Uncomplicated Malaria Patients in Southern Vietnam

Abstract

If parasite genotype influences the clinical course of malaria, we expect that isolates from patients with similar pathology would be more closely related than would be expected by chance. To explore this prediction, we typed nine microsatellite markers in sympatric Plasmodium falciparum isolates from cerebral and uncomplicated malaria patients from Vietnam. Temporal structure and linkage disequilibrium were also examined in this data set.

Genetic relatedness of Plasmodium falciparum isolates and the origin of allelic diversity at the merozoite surface protein-1 (MSP-1) locus in Brazil and Vietnam

“…The epidemic propagation of a few discrete P. falciparum clones might explain these findings. This hypothesis is consistent with the epidemic structure (defined by Maynard Smith and colleagues [8] as the result of short-term expansions of highly successful clonal lineages in an otherwise panmictic population) that characterize most P. falciparum populations outside Africa, including those in Brazil [9] and Vietnam [10]. Since identical MSP-1 alleles have been found in the same area in Brazil over more than one decade [5], some epidemic clones could have remained relatively unchanged over several generations.…”

“…Blood samples were collected, after informed consent, at malaria treatment facilities, and all patients had symptomatic P. falciparum infections when enrolled. The average proportions of multiple-clone P. falciparum infections, as estimated by microsatellite typing, were 11.5% in Rondônia, Brazil [9], and 39.6% in Bao Loc, Vietnam [10]. MSP-1 alleles had been previously characterized in these isolates by combining PCR typing with allele-specific primers and partial DNA sequencing (Figure 1A); each allele was defined as a unique combination of block 2 and 17 haplotypes and other polymorphisms across the molecule (Figure 1B) [5].…”

“…Length variation of PCR products (a single PCR product was obtained for each locus in each isolate) was measured on either ABI377 (all Brazilian samples) or ABI3100 (all Vietnamese samples) automated DNA sequencers (Applied Biosystems). Part of these microsatellite data had been published elsewhere [9,10]. …”

Parasite Polymorphism and Severe Malaria in Dakar (Senegal): A West African Urban Area

“…These data are in agreement with Nzila [25] and Conway [26], but not with Ferreira [27]. All parasite isolates collected from patients who subsequently died were polyclonal.…”

Microsatellite characterization of Plasmodium falciparum from symptomatic and non-symptomatic infections from the Western Amazon reveals the existence of non-symptomatic infection-associated genotypes

“…In a previous report from parasite samples from French-Guyana (Ariey et al 2001), different genotypes of P. falciparum and certain alleles of polymorphic genes were associated to severe disease. In another study in Vietnam (Ferreira et al 2002), where the circulating P. falciparum were genotyped using neutral microsatellites, the clinical outcome of the individual malaria cases could not be associated to specific P. falciparum genotypes.…”