Comparative population structure of Plasmodium malariae and Plasmodium falciparum under different transmission settings in Malawi
Abstract Background Described here is the first population genetic study of Plasmodium malariae , the causative agent of quartan malaria. Although not as deadly as Plasmodium falciparum , P. malariae is more common than previously thought, and is frequently in sympatry and co-infection with P. falci...
| Published in: | Malaria Journal |
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| Main Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
BMC
2011
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| Subjects: | |
| Online Access: | https://doi.org/10.1186/1475-2875-10-38 https://doaj.org/article/19787fb9abc44683b889f4d623f51284 |
| Summary: | Abstract Background Described here is the first population genetic study of Plasmodium malariae , the causative agent of quartan malaria. Although not as deadly as Plasmodium falciparum , P. malariae is more common than previously thought, and is frequently in sympatry and co-infection with P. falciparum , making its study increasingly important. This study compares the population parameters of the two species in two districts of Malawi with different malaria transmission patterns - one seasonal, one perennial - to explore the effects of transmission on population structures. Methods Six species-specific microsatellite markers were used to analyse 257 P. malariae samples and 257 P. falciparum samples matched for age, gender and village of residence. Allele sizes were scored to within 2 bp for each locus and haplotypes were constructed from dominant alleles in multiple infections. Analysis of multiplicity of infection (MOI), population differentiation, clustering of haplotypes and linkage disequilibrium was performed for both species. Regression analyses were used to determine association of MOI measurements with clinical malaria parameters. Results Multiple-genotype infections within each species were common in both districts, accounting for 86.0% of P. falciparum and 73.2% of P. malariae infections and did not differ significantly with transmission setting. Mean MOI of P. falciparum was increased under perennial transmission compared with seasonal (3.14 vs 2.59, p = 0.008) and was greater in children compared with adults. In contrast, P. malariae mean MOI was similar between transmission settings (2.12 vs 2.11) and there was no difference between children and adults. Population differentiation showed no significant differences between villages or districts for either species. There was no evidence of geographical clustering of haplotypes. Linkage disequilibrium amongst loci was found only for P. falciparum samples from the seasonal transmission setting. Conclusions The extent of similarity between P. falciparum ... |
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