Maintenance of high temporal Plasmodium falciparum genetic diversity and complexity of infection in asymptomatic and symptomatic infections in Kilifi, Kenya from 2007 to 2018
© 2022. The Author(s)..
BACKGROUND: High levels of genetic diversity are common characteristics of Plasmodium falciparum parasite populations in high malaria transmission regions. There has been a decline in malaria transmission intensity over 12 years of surveillance in the community in Kilifi, Kenya. This study sought to investigate whether there was a corresponding reduction in P. falciparum genetic diversity, using msp2 as a genetic marker.
METHODS: Blood samples were obtained from children (< 15 years) enrolled into a cohort with active weekly surveillance between 2007 and 2018 in Kilifi, Kenya. Asymptomatic infections were defined during the annual cross-sectional blood survey and the first-febrile malaria episode was detected during the weekly follow-up. Parasite DNA was extracted and successfully genotyped using allele-specific nested polymerase chain reactions for msp2 and capillary electrophoresis fragment analysis.
RESULTS: Based on cross-sectional surveys conducted in 2007-2018, there was a significant reduction in malaria prevalence (16.2-5.5%: P-value < 0.001), however msp2 genetic diversity remained high. A high heterozygosity index (He) (> 0.95) was observed in both asymptomatic infections and febrile malaria over time. About 281 (68.5%) asymptomatic infections were polyclonal (> 2 variants per infection) compared to 46 (56%) polyclonal first-febrile infections. There was significant difference in complexity of infection (COI) between asymptomatic 2.3 [95% confidence interval (CI) 2.2-2.5] and febrile infections 2.0 (95% CI 1.7-2.3) (P = 0.016). Majority of asymptomatic infections (44.2%) carried mixed alleles (i.e., both FC27 and IC/3D7), while FC27 alleles were more frequent (53.3%) among the first-febrile infections.
CONCLUSIONS: Plasmodium falciparum infections in Kilifi are still highly diverse and polyclonal, despite the reduction in malaria transmission in the community.
| Medienart: |
E-Artikel |
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| Erscheinungsjahr: |
2022 |
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| Erschienen: |
2022 |
| Enthalten in: |
Zur Gesamtaufnahme - volume:21 |
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| Enthalten in: |
Malaria journal - 21(2022), 1 vom: 20. Juni, Seite 192 |
| Sprache: |
Englisch |
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| Beteiligte Personen: |
Kimenyi, Kelvin M [VerfasserIn] |
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| Links: |
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| Themen: |
Antigens, Protozoan |
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| Anmerkungen: |
Date Completed 22.06.2022 Date Revised 16.07.2022 published: Electronic Citation Status MEDLINE |
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| doi: |
10.1186/s12936-022-04213-7 |
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| funding: |
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| Förderinstitution / Projekttitel: |
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| PPN (Katalog-ID): |
NLM342466879 |
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| 100 | 1 | |a Kimenyi, Kelvin M |e verfasserin |4 aut | |
| 245 | 1 | 0 | |a Maintenance of high temporal Plasmodium falciparum genetic diversity and complexity of infection in asymptomatic and symptomatic infections in Kilifi, Kenya from 2007 to 2018 |
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| 500 | |a Date Revised 16.07.2022 | ||
| 500 | |a published: Electronic | ||
| 500 | |a Citation Status MEDLINE | ||
| 520 | |a © 2022. The Author(s). | ||
| 520 | |a BACKGROUND: High levels of genetic diversity are common characteristics of Plasmodium falciparum parasite populations in high malaria transmission regions. There has been a decline in malaria transmission intensity over 12 years of surveillance in the community in Kilifi, Kenya. This study sought to investigate whether there was a corresponding reduction in P. falciparum genetic diversity, using msp2 as a genetic marker | ||
| 520 | |a METHODS: Blood samples were obtained from children (< 15 years) enrolled into a cohort with active weekly surveillance between 2007 and 2018 in Kilifi, Kenya. Asymptomatic infections were defined during the annual cross-sectional blood survey and the first-febrile malaria episode was detected during the weekly follow-up. Parasite DNA was extracted and successfully genotyped using allele-specific nested polymerase chain reactions for msp2 and capillary electrophoresis fragment analysis | ||
| 520 | |a RESULTS: Based on cross-sectional surveys conducted in 2007-2018, there was a significant reduction in malaria prevalence (16.2-5.5%: P-value < 0.001), however msp2 genetic diversity remained high. A high heterozygosity index (He) (> 0.95) was observed in both asymptomatic infections and febrile malaria over time. About 281 (68.5%) asymptomatic infections were polyclonal (> 2 variants per infection) compared to 46 (56%) polyclonal first-febrile infections. There was significant difference in complexity of infection (COI) between asymptomatic 2.3 [95% confidence interval (CI) 2.2-2.5] and febrile infections 2.0 (95% CI 1.7-2.3) (P = 0.016). Majority of asymptomatic infections (44.2%) carried mixed alleles (i.e., both FC27 and IC/3D7), while FC27 alleles were more frequent (53.3%) among the first-febrile infections | ||
| 520 | |a CONCLUSIONS: Plasmodium falciparum infections in Kilifi are still highly diverse and polyclonal, despite the reduction in malaria transmission in the community | ||
| 650 | 4 | |a Journal Article | |
| 650 | 4 | |a Complexity of infections | |
| 650 | 4 | |a Genetic diversity | |
| 650 | 4 | |a Kenya | |
| 650 | 4 | |a Malaria | |
| 650 | 4 | |a P. falciparum | |
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| 700 | 1 | |a Ngoi, Joyce M |e verfasserin |4 aut | |
| 700 | 1 | |a de Laurent, Zaydah R |e verfasserin |4 aut | |
| 700 | 1 | |a Ndwiga, Leonard |e verfasserin |4 aut | |
| 700 | 1 | |a Osoti, Victor |e verfasserin |4 aut | |
| 700 | 1 | |a Obiero, George |e verfasserin |4 aut | |
| 700 | 1 | |a Abdi, Abdirahman I |e verfasserin |4 aut | |
| 700 | 1 | |a Bejon, Philip |e verfasserin |4 aut | |
| 700 | 1 | |a Ochola-Oyier, Lynette Isabella |e verfasserin |4 aut | |
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