Effects of transmission reduction by insecticide-treated bed nets (ITNs) on parasite genetics population structure: I. The genetic diversity of Plasmodium falciparum parasites by microsatellite markers in western Kenya

Malaria Journal

Research

Simon Kariuki¹  Penelope Phillips-Howard²  Dianne Terlouw³  Feiko ter Kuile³  John Williamson⁴  John Gimnig⁴  William Hawley⁴  Kim Lindblade⁴  Ya Ping Shi⁴  Laurence Slutsker⁴  Sara Crawford⁴  Wangeci Gatei⁵  Mary Hamel⁶  Edward Walker⁷  Bernard Nahlen⁸ 

[1] Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya;Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya;Centre for Public Health, Liverpool John Moores University, Liverpool, UK;Liverpool School of Tropical Medicine, Liverpool, UK;Malaria Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA;Malaria Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA;Atlanta Research and Education Foundation, Atlanta, GA, USA;Malaria Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA;Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya;Michigan State University, East Lansing, USA;President's Malaria Initiative, Washington, DC, USA;

关键词: Linkage Disequilibrium;    Malaria;    Malaria Transmission;    Transmission Intensity;    Parasite Population;   

DOI  :  10.1186/1475-2875-9-353

 received in 2010-06-28, accepted in 2010-12-06,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundInsecticide-treated bed nets (ITNs) reduce malaria transmission and are an important prevention tool. However, there are still information gaps on how the reduction in malaria transmission by ITNs affects parasite genetics population structure. This study examined the relationship between transmission reduction from ITN use and the population genetic diversity of Plasmodium falciparum in an area of high ITN coverage in western Kenya.MethodsParasite genetic diversity was assessed by scoring eight single copy neutral multilocus microsatellite (MS) markers in samples collected from P. falciparum- infected children (< five years) before introduction of ITNs (1996, baseline, n = 69) and five years after intervention (2001, follow-up, n = 74).ResultsThere were no significant changes in overall high mixed infections and unbiased expected heterozygosity between baseline (%MA = 94% and He = 0.75) and follow up (%MA = 95% and He = 0.79) years. However, locus specific analysis detected significant differences for some individual loci between the two time points. Pfg377 loci, a gametocyte-specific MS marker showed significant increase in mixed infections and He in the follow up survey (%MA = 53% and He = 0.57) compared to the baseline (%MA = 30% and He = 0.29). An opposite trend was observed in the erythrocyte binding protein (EBP) MS marker. There was moderate genetic differentiation at the Pfg377 and TAA60 loci (FST = 0.117 and 0.137 respectively) between the baseline and post-ITN parasite populations. Further analysis revealed linkage disequilibrium (LD) of the microsatellites in the baseline (14 significant pair-wise tests and ISA = 0.016) that was broken in the follow up parasite population (6 significant pairs and ISA = 0.0003). The locus specific change in He, the moderate population differentiation and break in LD between the baseline and follow up years suggest an underlying change in population sub-structure despite the stability in the overall genetic diversity and multiple infection levels.ConclusionsThe results from this study suggest that although P. falciparum population maintained an overall stability in genetic diversity after five years of high ITN coverage, there was significant locus specific change associated with gametocytes, marking these for further investigation.

【 授权许可】

Unknown   
© Gatei et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.