Research
Genetic polymorphism of merozoite surface protein-1 and merozoite surface protein-2 in Plasmodium falciparum isolates from Brazzaville, Republic of Congo
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* Corresponding author: Francine Ntoumi fntoumi@fcrm-congo.com
1 Fondation Congolaise pour la Recherche Médicale, BP 2672 Brazzaville, Republic of Congo
2 Faculty of Health Sciences, University Marien Ngouabi, BP 2672, Brazzaville, Republic of Congo
3 Laboratoire de Pharmacologie, Centre d'Etudes sur les Ressources Végétales, BP 1249 Brazzaville, Republic of Congo
4 Centre de Recherche et d'Etude en Sciences Sociales et Humaines, BP 2019 Brazzaville, Republic of Congo
5 Institute for Tropical Medicine, University of Tübingen, 72074 Tübingen, Germany
Malaria Journal 2011, 10:276 doi:10.1186/1475-2875-10-276
Published: 22 September 2011Abstract
Background
The characterization of malaria parasite populations circulating in an area is part of site characterization, as a basis for evaluating the impact of malaria interventions on genetic diversity, parasite species, and multiplicity of infection. The present study was aimed at analysing genetic diversity of Plasmodium falciparum merozoite surface proteins 1 and 2 (MSP-1 and MSP-2) and to determine the multiplicity of infection in clinical isolates collected from children living in the Southern district of Brazzaville in the Republic of Congo.
Methods
A total of 125 isolates from patients with uncomplicated malaria attending Terinkyo and Madibou health centres were collected between January and June 2005 while evaluating the therapeutic efficacy of amodiaquine-artesunate combination. DNA was extracted and msp-1 and msp-2 genes were genotyped using allele-specific nested-PCR.
Results
Out of 468 distinct fragments detected, 15 msp-1 and 20 msp-2 genotypes were identified. For the msp-1 gene, K1 family was the predominant allelic type carried alone or in association with RO33 and Mad20 types, whereas the 3D7 family was the most prevalent in the msp-2 gene. Overall, the mean multiplicity of infection was 2.2. Out of 125 samples, 104 (83%) harboured more than one parasite genotype. There was no statistical significant difference in the multiplicity of infection by either sex or age of patients. However, a statistically significant correlation was found between parasite densities and the number of genotypes.
Conclusion
Polymorphism in P. falciparum clinical isolates from Brazzaville was high and mainly of multiple clones. The basis for the positive association between parasite densities and multiplicity of infection is discussed.