Hidden Plasmodium falciparum parasites in human infections: different genotype distribution in the peripheral circulation and in the placenta.
Sequestration of the mature Plasmodium falciparum forms complicates detection, quantification and molecular analysis of human infections. Whether the circulating parasites represent all or only a subset of co-infecting genotypes is unclear. We have investigated this issue and compared placenta and peripheral blood msp1 and msp2 genotypes in 58 women delivering with an ICT-positive placenta in Guediawaye, Senegal. Most placenta (91%) and blood samples (98%) were multiply infected. Multiplicity of infection was positively correlated in both tissues. However, the placental and circulating genotype profiles differed markedly. Only 10% of matched peripheral blood/placenta samples had identical genotypes, whereas 74% had only partially concordant genotypes, with some alleles detected in both tissues, together with additional allele(s) detected in one tissue only. Eight women (14%) had totally discordant placental and peripheral blood genotypes. Thus, in the vast majority of cases, some sequestered genotypes remain hidden, undetected in the peripheral circulation, indicating that analysis of peripheral parasites generates a partial picture of a P. falciparum infection.
Schleiermacher
Dietlind
D
Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique Unité de Recherche Associée 1960, Institut Pasteur, 25 Rue du Dr. Roux, 75015 Paris, France.
Le Hesran
Jean-Yves
JY
Ndiaye
Jean-Louis
JL
Perraut
Ronald
R
Gaye
Alioune
A
Mercereau-Puijalon
Odile
O
D000818:Animals; D005260:Female; D005787:Gene Frequency; D006801:Humans; D016778:Malaria, Falciparum / Q000097:blood*; D010920:Placenta / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000235:genetics* / Q000472:pathogenicity