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.

Wangeci Gatei; Simon Kariuki; William Hawley; Feiko Ter Kuile; Anja Terlouw; Penelope Phillips-Howard; Bernard Nahlen; John Gimnig; Kim Lindblade; Edward Walker; Mary Hamel; Sara Crawford; John Williamson; Laurence Slutsker; Ya Ping Shi

doi:10.1186/1475-2875-9-353

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.

Wangeci Gatei
, Simon Kariuki
, William Hawley
, Feiko Ter Kuile
, Anja Terlouw
, Penelope Phillips-Howard
, Bernard Nahlen
, John Gimnig
, Kim Lindblade
, Edward Walker
, Mary Hamel
, Sara Crawford
, John Williamson
, Laurence Slutsker
, Ya Ping Shi

Clinical Sciences

Research output: Contribution to journal › Article › peer-review

24 Citations (Scopus)

Abstract

Background: Insecticide-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.

Methods: Parasite 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).

Results: There 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 IS

A = 0.016) that was broken in the follow up parasite population (6 significant pairs and IS

A = 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.

Conclusions: The 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.

Original language	English
Article number	353
Journal	Malaria Journal
Volume	9
Issue number	1
DOIs	https://doi.org/10.1186/1475-2875-9-353
Publication status	Published - 6 Dec 2010

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Gatei, W., Kariuki, S., Hawley, W., Ter Kuile, F., Terlouw, A., Phillips-Howard, P., Nahlen, B., Gimnig, J., Lindblade, K., Walker, E., Hamel, M., Crawford, S., Williamson, J., Slutsker, L., & Shi, Y. P. (2010). 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, 9(1), Article 353. https://doi.org/10.1186/1475-2875-9-353

@article{dd20449b53da4676856b987352d846c3,

title = "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.",

abstract = "Background: Insecticide-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 parasitegenetics population structure. This study examined the relationship between transmission reduction from ITN useand the population genetic diversity of Plasmodium falciparum in an area of high ITN coverage in western Kenya.Methods: Parasite 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).Results: There were no significant changes in overall high mixed infections and unbiased expected heterozygositybetween baseline (\%MA = 94\% and He = 0.75) and follow up (\%MA = 95\% and He = 0.79) years. However, locusspecific 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 wasobserved in the erythrocyte binding protein (EBP) MS marker. There was moderate genetic differentiation at thePfg377 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-wisetests 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 baselineand follow up years suggest an underlying change in population sub-structure despite the stability in the overallgenetic diversity and multiple infection levels.Conclusions: The results from this study suggest that although P. falciparum population maintained an overallstability in genetic diversity after five years of high ITN coverage, there was significant locus specific changeassociated with gametocytes, marking these for further investigation.",

author = "Wangeci Gatei and Simon Kariuki and William Hawley and \{Ter Kuile\}, Feiko and Anja Terlouw and Penelope Phillips-Howard and Bernard Nahlen and John Gimnig and Kim Lindblade and Edward Walker and Mary Hamel and Sara Crawford and John Williamson and Laurence Slutsker and Shi, \{Ya Ping\}",

year = "2010",

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day = "6",

doi = "10.1186/1475-2875-9-353",

language = "English",

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Gatei, W, Kariuki, S, Hawley, W, Ter Kuile, F , Terlouw, A , Phillips-Howard, P, Nahlen, B, Gimnig, J, Lindblade, K, Walker, E, Hamel, M, Crawford, S, Williamson, J, Slutsker, L & Shi, YP 2010, '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, vol. 9, no. 1, 353. https://doi.org/10.1186/1475-2875-9-353

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. / Gatei, Wangeci; Kariuki, Simon; Hawley, William et al.
In: Malaria Journal, Vol. 9, No. 1, 353, 06.12.2010.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - 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.

AU - Gatei, Wangeci

AU - Kariuki, Simon

AU - Hawley, William

AU - Ter Kuile, Feiko

AU - Terlouw, Anja

AU - Phillips-Howard, Penelope

AU - Nahlen, Bernard

AU - Gimnig, John

AU - Lindblade, Kim

AU - Walker, Edward

AU - Hamel, Mary

AU - Crawford, Sara

AU - Williamson, John

AU - Slutsker, Laurence

AU - Shi, Ya Ping

PY - 2010/12/6

Y1 - 2010/12/6

N2 - Background: Insecticide-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 parasitegenetics population structure. This study examined the relationship between transmission reduction from ITN useand the population genetic diversity of Plasmodium falciparum in an area of high ITN coverage in western Kenya.Methods: Parasite 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).Results: There were no significant changes in overall high mixed infections and unbiased expected heterozygositybetween baseline (%MA = 94% and He = 0.75) and follow up (%MA = 95% and He = 0.79) years. However, locusspecific 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 wasobserved in the erythrocyte binding protein (EBP) MS marker. There was moderate genetic differentiation at thePfg377 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-wisetests 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 baselineand follow up years suggest an underlying change in population sub-structure despite the stability in the overallgenetic diversity and multiple infection levels.Conclusions: The results from this study suggest that although P. falciparum population maintained an overallstability in genetic diversity after five years of high ITN coverage, there was significant locus specific changeassociated with gametocytes, marking these for further investigation.

AB - Background: Insecticide-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 parasitegenetics population structure. This study examined the relationship between transmission reduction from ITN useand the population genetic diversity of Plasmodium falciparum in an area of high ITN coverage in western Kenya.Methods: Parasite 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).Results: There were no significant changes in overall high mixed infections and unbiased expected heterozygositybetween baseline (%MA = 94% and He = 0.75) and follow up (%MA = 95% and He = 0.79) years. However, locusspecific 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 wasobserved in the erythrocyte binding protein (EBP) MS marker. There was moderate genetic differentiation at thePfg377 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-wisetests 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 baselineand follow up years suggest an underlying change in population sub-structure despite the stability in the overallgenetic diversity and multiple infection levels.Conclusions: The results from this study suggest that although P. falciparum population maintained an overallstability in genetic diversity after five years of high ITN coverage, there was significant locus specific changeassociated with gametocytes, marking these for further investigation.

U2 - 10.1186/1475-2875-9-353

DO - 10.1186/1475-2875-9-353

M3 - Article

SN - 1475-2875

VL - 9

JO - Malaria Journal

JF - Malaria Journal

IS - 1

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