Plasmodium falciparum population dynamics during the early phase of anti-malarial drug treatment in Tanzanian children with acute uncomplicated malaria
Anja M Carlsson, Billy E Ngasala, Sabina Dahlström, Christopher Membi, Isabel M Veiga, Lars Rombo, Salim Abdulla, Zul Premji, J Pedro Gil, Anders Björkman, Andreas Mårtensson, Anja M Carlsson, Billy E Ngasala, Sabina Dahlström, Christopher Membi, Isabel M Veiga, Lars Rombo, Salim Abdulla, Zul Premji, J Pedro Gil, Anders Björkman, Andreas Mårtensson
Abstract
Background: This study aimed to explore Plasmodium falciparum population dynamics during the early phase of anti-malarial drug treatment with artemisinin-based combination therapy in children with clinical malaria in a high transmission area in Africa.
Methods: A total of 50 children aged 1-10 years with acute uncomplicated P. falciparum malaria in Bagamoyo District, Tanzania, were enrolled. Participants were hospitalized and received supervised standard treatment with artemether-lumefantrine according to body weight in six doses over 3 days. Blood samples were collected 11 times, i.e. at time of diagnosis (-2 h) and 0, 2, 4, 8, 16, 24, 36, 48, 60 and 72 h after initiation of treatment. Parasite population dynamics were assessed using nested polymerase chain reaction (PCR)-genotyping of merozoite surface protein (msp) 1 and 2.
Results: PCR-analyses from nine sequential blood samples collected after initiation of treatment identified 20 and 21 additional genotypes in 15/50 (30%) and 14/50 (28%) children with msp1 and msp2, respectively, non-detectable in the pre-treatment samples (-2 and 0 h combined). Some 15/20 (75%) and 14/21 (67%) of these genotypes were identified within 24 h, whereas 17/20 (85%) and 19/21 (90%) within 48 h for msp1 and msp2, respectively. The genotype profile was diverse, and varied considerably over time both within and between patients, molecular markers and their respective families.
Conclusion: PCR analyses from multiple blood samples collected during the early treatment phase revealed a complex picture of parasite sub-populations. This underlines the importance of interpreting PCR-outcomes with caution and suggests that the present use of PCR-adjustment from paired blood samples in anti-malarial drug trials may overestimate assessment of drug efficacy in high transmission areas in Africa.The study is registered at http://www.clinicaltrials.gov with identifier NCT00336375.
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References
- World Health Organization. Guidelines for the treatment of malaria. 2. Geneva: WHO; 2010.
- Venture MfM, World Health Organization. Methods and techniques for clinical trials on antimalarial drug efficacy: genotyping to identify parasite populations. Informal consultation organized by the MMV and cosponsored by the WHO 29-31 May 2007 Amsterdam; 2008.
- Snounou G, Beck HP. The use of PCR genotyping in the assessment of recrudescence or reinfection after antimalarial drug treatment. Parasitol Today. 1998;14:462–467. doi: 10.1016/S0169-4758(98)01340-4.
- Juliano JJ, Gadalla N, Sutherland CJ, Meshnick SR. The perils of PCR: can we accurately 'correct' antimalarial trials? Trends Parasitol. 2010;26:119–124. doi: 10.1016/j.pt.2009.12.007.
- World Health Organization. Assessment and monitoring of antimalarial drug efficacy for the treatment of uncomplicated falciparum malaria. Geneva; 2003.
- Farnert A, Snounou G, Rooth I, Bjorkman A. Daily dynamics of Plasmodium falciparum subpopulations in asymptomatic children in a holoendemic area. Am J Trop Med Hyg. 1997;56:538–547.
- Jafari-Guemouri S, Boudin C, Fievet N, Ndiaye P, Deloron P. Plasmodium falciparum genotype population dynamics in asymptomatic children from Senegal. Microbes Infect. 2006;8:1663–1670. doi: 10.1016/j.micinf.2006.01.023.
- Farnert A, Bjorkman A. Short report: Limited advantage of multiple consecutive samples for genotyping Plasmodium falciparum populations during the first days of treatment. Am J Trop Med Hyg. 2005;73:204–206.
- Jafari S, Le J, Bouchaud O, Durand R. Plasmodium falciparum clonal population dynamics during malaria treatment. J Infect Dis. 2004;189:195–203. doi: 10.1086/380910.
- Missinou MA, Kun JFJ, Kremsner PG. No change in parasite genotype during single episodes of Plasmodium falciparum malaria in Gabonese children. Parasitol Res. 2004;93:322–327.
- Martensson A, Ngasala B, Ursing J, Veiga MI, Wiklund L, Membi C, Montgomery SM, Premji Z, Farnert A, Bjorkman A. Influence of consecutive-day blood sampling on polymerase chain reaction-adjusted parasitological cure rates in an antimalarial-drug trial conducted in Tanzania. J Infect Dis. 2007;195:597–601. doi: 10.1086/510910.
- U.S National Institute of Health Clinical Trial register.
- Hietala SF, Martensson A, Ngasala B, Dahlstrom S, Lindegardh N, Annerberg A, Premji Z, Farnert A, Gil P, Bjorkman A, Ashton M. Population Pharmacokinetics and pharmacodynamics of artemether and lumefantrine during combination treatment in children with uncomplicated falciparum malaria in Tanzania. Antimicrob Agents Chemother. 2010;54:4780–4788. doi: 10.1128/AAC.00252-10.
- Dahlstrom S, Veiga MI, Ferreira P, Martensson A, Kaneko A, Andersson B, Bjorkman A, Gil JP. Diversity of the sarco/endoplasmic reticulum Ca2+ - ATPase orthologue of Plasmodium falciparum (PfATP6) Infection Genetics and Evolution. 2008;8:340–345. doi: 10.1016/j.meegid.2008.02.002.
- Farnert A, Arez AP, Babiker HA, Beck HP, Benito A, Bjorkman A, Bruce MC, Conway DJ, Day KP, Henning L, Mercereau-Puijalon O, Ranford-Cartwright LC, Rubio JM, Snounou G, Walliker D, Zwetyenga J, do Rosario VE. Genotyping of Plasmodium falciparum infections by PCR: a comparative multicentre study. Trans R Soc Trop Med Hyg. 2001;95:225–232. doi: 10.1016/S0035-9203(01)90175-0.
- Cattamanchi A, Kyabayinze D, Hubbard A, Rosenthal PJ, Dorsey G. Distinguishing recrudescence from reinfection in a longitudinal antimalarial drug efficacy study: comparison of results based on genotyping of msp-1, msp-2, and glurp. Am J Trop Med Hyg. 2003;68:133–139.
- Snounou G, Zhu XP, Siripoon N, Jarra W, Thaithong S, Brown KN, Viriyakosol S. Biased distribution of msp1 and msp2 allelic variants in Plasmodium falciparum populations in Thailand. Trans R Soc Trop Med Hyg. 1999;93:369–374. doi: 10.1016/S0035-9203(99)90120-7.
- Bereczky S, Martensson A, Gil JP, Farnert A. Short report: Rapid DNA extraction from archive blood spots on filter paper for genotyping of Plasmodium falciparum. Am J Trop Med Hyg. 2005;72:249–251.
- Liljander A, Wiklund L, Falk N, Kweku M, Martensson A, Felger I, Farnert A. Optimization and validation of multi-coloured capillary electrophoresis for genotyping of Plasmodium falciparum merozoite surface proteins (msp1 and 2) Malar J. 2009;8:78. doi: 10.1186/1475-2875-8-78.
Source: PubMed