Diversity of Plasmodium falciparum clones infecting children living in a holoendemic area in north-eastern Tanzania.
The diversity of Plasmodium falciparum clones and their role in progression from asymptomatic to symptomatic condition in children have been investigated. Attempts to identify whether particular parasite genotypes were associated with the development of clinical symptoms have been made. A cohort of 34 initially asymptomatic parasitaemic children aged 1-5 years were followed daily for 31 days. Clinical examinations were made each day for signs and symptoms of clinical malaria, followed by parasitological investigation. Nineteen children developed symptoms suggestive of clinical malaria during this period. Daily blood parasite samples from 13 children who developed clinical malaria symptoms and 7 who remained asymptomatic were genotyped by PCR-amplification of the polymorphic regions of the merozoite surface proteins 1 and 2 (MSP1 and MSP2) and the glutamate rich protein (GLURP) genes. Infections were found to be highly complex in both groups of children. Every isolate examined from both groups had a mixture of parasite clones. Daily changes were observed in both parasite density and genotypic pattern. The mean number of genotypes per individual was estimated at 4.9 and 2.7 for asymptomatic and symptomatic groups of children, respectively. Analysis of allele frequency distributions showed that these differed significantly for the MSP1 locus only.
Magesa
S M
SM
National Institute for Medical Research, Ubwari Field Station, P O Box 81, Muheza, Tanzania. smagea@hotmail.com
Mdira
K Y
KY
Babiker
H A
HA
Alifrangis
M
M
Färnert
A
A
Simonsen
P E
PE
Bygbjerg
I C
IC
Walliker
D
D
Jakobsen
P H
PH
D000483:Alleles; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics / Q000302:isolation & purification; D002675:Child, Preschool; D002999:Clone Cells; D005838:Genotype; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000235:genetics*; D020066:Merozoite Surface Protein 1 / Q000235:genetics / Q000302:isolation & purification; D010963:Plasmodium falciparum / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000235:genetics / Q000302:isolation & purification; D013636:Tanzania
D000953:Antigens, Protozoan; D020066:Merozoite Surface Protein 1; D015800:Protozoan Proteins; C065974:merozoite surface protein 2, Plasmodium