Genetic diversity of Plasmodium falciparum among school-aged children from the Man region, western Côte d'Ivoire.
BACKGROUND
The genetic diversity of Plasmodium falciparum allows the molecular discrimination of otherwise microscopically identical parasites and the identification of individual clones in multiple infections. The study reported here investigated the P. falciparum multiplicity of infection (MOI) and genetic diversity among school-aged children in the Man region, western Côte d'Ivoire.


METHODS
Blood samples from 292 children aged seven to 15 years were collected in four nearby villages located at altitudes ranging from 340 to 883 m above sea level. Giemsa-stained thick and thin blood films were prepared and examined under a microscope for P. falciparum prevalence and parasitaemia. MOI and genetic diversity of the parasite populations were investigated using msp2 typing by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).


RESULTS
Plasmodium falciparum prevalence and parasitaemia were both found to be significantly lower in the highest altitude village. Genotyping of the isolates revealed 25 potentially new msp2 alleles. MOI varied significantly across villages but did not correlate with altitude nor children's age, and only to a limited extent with parasitaemia. An analysis of molecular variance (AMOVA) indicated that a small, but close to statistical significance (p = 0.07), fraction of variance occurs specifically between villages of low and high altitudes.


CONCLUSIONS
Higher altitude was associated with lower prevalence of P. falciparum but not with reduced MOI, suggesting that, in this setting, MOI is not a good proxy for transmission. The evidence for partially parted parasite populations suggests the existence of local geographical barriers that should be taken into account when deploying anti-malarial interventions.
Sarah E
SE
Mara
Kigbafori D
KD
Silué
Giovanna
G
Raso
Simon P
SP
N'guetta
Eliézer K
EK
N'goran
Marcel
M
Tanner
Jürg
J
Utzinger
Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303 Abidjan 01, Côte d'Ivoire. xavier.ding@gmail.com.
Xavier C
XC
Ding
D000293:Adolescent; D000953:Antigens, Protozoan / Q000235:genetics; D001769:Blood / Q000469:parasitology; D002648:Child; D007560:Cote d'Ivoire / Q000453:epidemiology; D005260:Female; D005787:Gene Frequency; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000469:parasitology*; D008297:Male; D059208:Parasite Load; D010963:Plasmodium falciparum / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D015800:Protozoan Proteins / Q000235:genetics; D012424:Rural Population; D013334:Students
D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C065974:merozoite surface protein 2, Plasmodium