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Maiga H, Morrison RD, Duffy PE. Sanger sequencing and deconvolution of polyclonal infections: a quantitative approach to monitor drug-resistant Plasmodium falciparum. EBioMedicine 2024; 103:105115. [PMID: 38636200 PMCID: PMC11031737 DOI: 10.1016/j.ebiom.2024.105115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 04/20/2024] Open
Abstract
BACKGROUND Anti-malarial drug resistance in Plasmodium falciparum is a major public health problem in malaria-endemic regions. Although various technical improvements in sequencing methods have been introduced to identify SNPs, the conventional approach with current tools does not discriminate mixed infections, and thus can be improved for more sensitive surveillance of anti-malarial resistance to better inform control strategies. METHODS We developed a computational approach for deconvolution of chromatograms generated by standard Sanger sequencing of PCR amplicons in order to quantify molecular marker variants of anti-malarial drug resistance genes [Plasmodium falciparum dihydropteorate synthase (Pfdhps) and P. falciparum dihydrofolate reductase (Pfdhfr)]. We validated this computational approach using mixtures of V1/S and FCR3 at varying proportions between 0 and 100%, then applied it to field samples collected in Doneguebougou, Mali in 2018. We determined the mean fraction of resistance alleles in individual samples, as well as the prevalence of infections carrying resistant parasites. FINDINGS We observed a highly significant correlation between the predicted and measured proportions of V1/S and FCR3 alleles in mixed laboratory samples (all p < 0.001). Among field samples, the mean fraction of resistant Pfdhps alleles was 4.7% 431V, 95.9% 436F/A, 49.9% 437G, 0.0% 540E, 1.2% 581G and 1.5% 613S/T; corresponding prevalences were 50.0%, 100%, 72.5%, 0.0%, 25.0%, and 12.5%, respectively. The mean fraction of resistant Pfdhfr alleles was 0.6% 16V, 11.1% 50R, 89.0% 51I, 98.3% 59R, 74.7% 108T/N, 8.6% 140L and 8.7% 164L; corresponding prevalences were 12.5%, 75.0%, 100%, 100%, 100%, 50.0%, and 28.6%, respectively. We identified two new point mutations on the Pfdhps gene at codons D484T and D545N. INTERPRETATION Computational deconvolution of sequencing chromatograms can discriminate varying proportions of antimalarial drug-sensitive versus -resistant alleles. This cost-effective and quantitative variant-sequencing approach will be useful for population-based surveys that characterize mixed infections at the individual level to survey known and unknown mutations in P. falciparum drug-resistance genes. FUNDING This work was supported by the Division of Intramural Research of the National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH). HM was supported by the African Postdoctoral Training Initiative (APTI) Fellowship program jointly managed by the US NIH, The African Academy of Sciences (AAS) and Bill & Melinda Gates Foundation (BMGF); Grant Reference Number: APTI-18-01.
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Affiliation(s)
- Hamma Maiga
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 29 Lincoln Drive, Bethesda, MD, 20892, USA; Institut National de Santé Publique (INSP), Ministère de la Santé et du Développement Social (MSDS), Bamako, BP: 1771, Mali.
| | - Robert D Morrison
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 29 Lincoln Drive, Bethesda, MD, 20892, USA
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), 29 Lincoln Drive, Bethesda, MD, 20892, USA
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2
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Wong W, Schaffner SF, Thwing J, Seck MC, Gomis J, Diedhiou Y, Sy N, Ndiop M, Ba F, Diallo I, Sene D, Diallo MA, Ndiaye YD, Sy M, Sene A, Sow D, Dieye B, Tine A, Ribado J, Suresh J, Lee A, Battle KE, Proctor JL, Bever CA, MacInnis B, Ndiaye D, Hartl DL, Wirth DF, Volkman SK. Evaluating the performance of Plasmodium falciparum genetic metrics for inferring National Malaria Control Programme reported incidence in Senegal. Malar J 2024; 23:68. [PMID: 38443939 PMCID: PMC10916253 DOI: 10.1186/s12936-024-04897-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 02/29/2024] [Indexed: 03/07/2024] Open
Abstract
BACKGROUND Genetic surveillance of the Plasmodium falciparum parasite shows great promise for helping National Malaria Control Programmes (NMCPs) assess parasite transmission. Genetic metrics such as the frequency of polygenomic (multiple strain) infections, genetic clones, and the complexity of infection (COI, number of strains per infection) are correlated with transmission intensity. However, despite these correlations, it is unclear whether genetic metrics alone are sufficient to estimate clinical incidence. METHODS This study examined parasites from 3147 clinical infections sampled between the years 2012-2020 through passive case detection (PCD) across 16 clinic sites spread throughout Senegal. Samples were genotyped with a 24 single nucleotide polymorphism (SNP) molecular barcode that detects parasite strains, distinguishes polygenomic (multiple strain) from monogenomic (single strain) infections, and identifies clonal infections. To determine whether genetic signals can predict incidence, a series of Poisson generalized linear mixed-effects models were constructed to predict the incidence level at each clinical site from a set of genetic metrics designed to measure parasite clonality, superinfection, and co-transmission rates. RESULTS Model-predicted incidence was compared with the reported standard incidence data determined by the NMCP for each clinic and found that parasite genetic metrics generally correlated with reported incidence, with departures from expected values at very low annual incidence (< 10/1000/annual [‰]). CONCLUSIONS When transmission is greater than 10 cases per 1000 annual parasite incidence (annual incidence > 10‰), parasite genetics can be used to accurately infer incidence and is consistent with superinfection-based hypotheses of malaria transmission. When transmission was < 10‰, many of the correlations between parasite genetics and incidence were reversed, which may reflect the disproportionate impact of importation and focal transmission on parasite genetics when local transmission levels are low.
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Affiliation(s)
- Wesley Wong
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Stephen F Schaffner
- Infectious Disease and Microbiome Program, The Broad Institute, Cambridge, MA, USA
| | - Julie Thwing
- Malaria Branch, Division of Parasitic Diseases and Malaria, Global Health Center, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Mame Cheikh Seck
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Jules Gomis
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Younouss Diedhiou
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Ngayo Sy
- Section de Lutte Anti-Parasitaire (SLAP) Clinic, Thies, Senegal
| | - Medoune Ndiop
- Programme National de Lutte contre le Paludisme (PNLP), Dakar, Senegal
| | - Fatou Ba
- Programme National de Lutte contre le Paludisme (PNLP), Dakar, Senegal
| | - Ibrahima Diallo
- Programme National de Lutte contre le Paludisme (PNLP), Dakar, Senegal
| | - Doudou Sene
- Programme National de Lutte contre le Paludisme (PNLP), Dakar, Senegal
| | - Mamadou Alpha Diallo
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Yaye Die Ndiaye
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Mouhamad Sy
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Aita Sene
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Djiby Sow
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Baba Dieye
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Abdoulaye Tine
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Jessica Ribado
- Institute for Disease Modeling at the Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - Joshua Suresh
- Institute for Disease Modeling at the Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - Albert Lee
- Institute for Disease Modeling at the Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - Katherine E Battle
- Institute for Disease Modeling at the Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - Joshua L Proctor
- Institute for Disease Modeling at the Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - Caitlin A Bever
- Institute for Disease Modeling at the Bill and Melinda Gates Foundation, Seattle, WA, USA
| | - Bronwyn MacInnis
- Infectious Disease and Microbiome Program, The Broad Institute, Cambridge, MA, USA
| | - Daouda Ndiaye
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS), Dakar, Senegal
| | - Daniel L Hartl
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
- Infectious Disease and Microbiome Program, The Broad Institute, Cambridge, MA, USA
| | - Sarah K Volkman
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
- Infectious Disease and Microbiome Program, The Broad Institute, Cambridge, MA, USA.
- College of Natural, Behavioral, and Health Sciences, Simmons University, Boston, MA, USA.
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3
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Zhan Q, He Q, Tiedje KE, Day KP, Pascual M. Hyper-diverse antigenic variation and resilience to transmission-reducing intervention in falciparum malaria. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.02.01.24301818. [PMID: 38370729 PMCID: PMC10871444 DOI: 10.1101/2024.02.01.24301818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Intervention against falciparum malaria in high transmission regions remains challenging, with relaxation of control efforts typically followed by rapid resurgence. Resilience to intervention co-occurs with incomplete immunity, whereby children eventually become protected from severe disease but not infection and a large transmission reservoir results from high asymptomatic prevalence across all ages. Incomplete immunity relates to the vast antigenic variation of the parasite, with the major surface antigen of the blood stage of infection encoded by the multigene family known as var. Recent deep sampling of var sequences from individual isolates in northern Ghana showed that parasite population structure exhibited persistent features of high-transmission regions despite the considerable decrease in prevalence during transient intervention with indoor residual spraying (IRS). We ask whether despite such apparent limited impact, the transmission system had been brought close to a transition in both prevalence and resurgence ability. With a stochastic agent-based model, we investigate the existence of such a transition to pre-elimination with intervention intensity, and of molecular indicators informative of its approach. We show that resurgence ability decreases sharply and nonlinearly across a narrow region of intervention intensities in model simulations, and identify informative molecular indicators based on var gene sequences. Their application to the survey data indicates that the transmission system in northern Ghana was brought close to transition by IRS. These results suggest that sustaining and intensifying intervention would have pushed malaria dynamics to a slow-rebound regime with an increased probability of local parasite extinction.
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Affiliation(s)
- Qi Zhan
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago; Chicago, IL, 60637, USA
| | - Qixin He
- Department of Biological Sciences, Purdue University; West Lafayette, IN, 47907, USA
| | - Kathryn E Tiedje
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
| | - Karen P Day
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
| | - Mercedes Pascual
- Department of Biology, New York University; New York, NY, 10012, USA
- Department of Environmental Studies, New York University; New York, NY, 10012, USA
- Santa Fe Institute; Santa Fe, NM, 87501, USA
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4
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Wong W, Schaffner SF, Thwing J, Seck MC, Gomis J, Diedhiou Y, Sy N, Ndiop M, Ba F, Diallo I, Sene D, Diallo MA, Ndiaye YD, Sy M, Sene A, Sow D, Dieye B, Tine A, Ribado J, Suresh J, Lee A, Battle KE, Proctor JL, Bever CA, MacInnis B, Ndiaye D, Hartl DL, Wirth DF, Volkman SK. Evaluating the performance of Plasmodium falciparum genetics for inferring National Malaria Control Program reported incidence in Senegal. RESEARCH SQUARE 2023:rs.3.rs-3516287. [PMID: 37961451 PMCID: PMC10635402 DOI: 10.21203/rs.3.rs-3516287/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Genetic surveillance of the Plasmodium falciparum parasite shows great promise for helping National Malaria Control Programs (NMCPs) assess parasite transmission. Genetic metrics such as the frequency of polygenomic (multiple strain) infections, genetic clones, and the complexity of infection (COI, number of strains per infection) are correlated with transmission intensity. However, despite these correlations, it is unclear whether genetic metrics alone are sufficient to estimate clinical incidence. Here, we examined parasites from 3,147 clinical infections sampled between the years 2012-2020 through passive case detection (PCD) across 16 clinic sites spread throughout Senegal. Samples were genotyped with a 24 single nucleotide polymorphism (SNP) molecular barcode that detects parasite strains, distinguishes polygenomic (multiple strain) from monogenomic (single strain) infections, and identifies clonal infections. To determine whether genetic signals can predict incidence, we constructed a series of Poisson generalized linear mixed-effects models to predict the incidence level at each clinical site from a set of genetic metrics designed to measure parasite clonality, superinfection, and co-transmission rates. We compared the model-predicted incidence with the reported standard incidence data determined by the NMCP for each clinic and found that parasite genetic metrics generally correlated with reported incidence, with departures from expected values at very low annual incidence (<10/1000/annual [‰]). When transmission is greater than 10 cases per 1000 annual parasite incidence (annual incidence >10 ‰), parasite genetics can be used to accurately infer incidence and is consistent with superinfection-based hypotheses of malaria transmission. When transmission was <10 ‰, we found that many of the correlations between parasite genetics and incidence were reversed, which we hypothesize reflects the disproportionate impact of importation and focal transmission on parasite genetics when local transmission levels are low.
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Affiliation(s)
| | | | | | - Mame Cheikh Seck
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Jules Gomis
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Younouss Diedhiou
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Ngayo Sy
- Section de Lutte Anti-Parasitaire (SLAP) Clinic
| | | | - Fatou Ba
- Programme National de Lutte Contre le Paludisme
| | - Ibrahima Diallo
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Doudou Sene
- Programme National de Lutte Contre le Paludisme
| | - Mamadou Alpha Diallo
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Yaye Die Ndiaye
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Mouhamad Sy
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Aita Sene
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Djiby Sow
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Baba Dieye
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Abdoulaye Tine
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
| | - Jessica Ribado
- Institute for Disease Modeling, Bill and Melinda Gates Foundation
| | - Joshua Suresh
- Institute for Disease Modeling, Bill and Melinda Gates Foundation
| | - Albert Lee
- Institute for Disease Modeling, Bill and Melinda Gates Foundation
| | | | - Joshua L Proctor
- Institute for Disease Modeling, Bill and Melinda Gates Foundation
| | - Caitlin A Bever
- Institute for Disease Modeling, Bill and Melinda Gates Foundation
| | | | - Daouda Ndiaye
- Centre International de recherche, de formation en Genomique Appliquee et de Surveillance Sanitaire (CIGASS)
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5
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Basco LK. Cultivation of Asexual Intraerythrocytic Stages of Plasmodium falciparum. Pathogens 2023; 12:900. [PMID: 37513747 PMCID: PMC10384318 DOI: 10.3390/pathogens12070900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
Successfully developed in 1976, the continuous in vitro culture of Plasmodium falciparum has many applications in the field of malaria research. It has become an important experimental model that directly uses a human pathogen responsible for a high prevalence of morbidity and mortality in many parts of the world and is a major source of biological material for immunological, biochemical, molecular, and pharmacological studies. Until present, the basic techniques described by Trager and Jensen and Haynes et al. remain unchanged in many malaria research laboratories. Nonetheless, different factors, including culture media, buffers, serum substitutes and supplements, sources of erythrocytes, and conditions of incubation (especially oxygen concentration), have been modified by different investigators to adapt the original technique in their laboratories or enhance the in vitro growth of the parasites. The possible effects and benefits of these modifications for the continuous cultivation of asexual intraerythrocytic stages of P. falciparum, as well as future challenges in developing a serum-free cultivation system and axenic cultures, are discussed.
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Affiliation(s)
- Leonardo K Basco
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique-Hôpitaux de Marseille (AP-HM), Service de Santé des Armées (SSA), Unité Mixte de Recherche (UMR) Vecteurs-Infections Tropicales et Méditerranéennes (VITROME), 13005 Marseille, France
- Institut Hospitalo-Universitaire-Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
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6
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Atuh NI, Anong DN, Jerome FC, Oriero E, Mohammed NI, D’Alessandro U, Amambua-Ngwa A. High genetic complexity but low relatedness in Plasmodium falciparum infections from Western Savannah Highlands and coastal equatorial Lowlands of Cameroon. Pathog Glob Health 2022; 116:428-437. [PMID: 34308788 PMCID: PMC9518281 DOI: 10.1080/20477724.2021.1953686] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To determine the diversity and connectivity of infections in Northwestern and Southwestern Cameroon, 232 Plasmodium falciparum infections, collected in 2018 from the Ndop Health District (NHD) in the western savannah highlands in the Northwest and the Limbe Health District (LHD) in the coastal lowland forests in the Southwest of Cameroon were genotyped for nine neutral microsatellite markers. Overall infection complexity and genetic diversity was significantly (p < 0.05) lower in NHD than LHD, (Mean MOI = 2.45 vs. 2.97; Fws = 0.42 vs. 0.47; Mean He = 0.84 vs. 0.89, respectively). Multi-locus linkage disequilibrium was generally low but significantly higher in the NHD than LHD population (mean ISA= 0.376 vs 0.093). Consequently, highly related pairs of isolates were observed in NHD (mean IBS = 0.086) compared to those from the LHD (mean IBS = 0.059). Infections from the two regions were mostly unrelated (mean IBS = 0.059), though the overall genetic differentiation across the geographical range was low. Indices of differentiation between the populations were however significant (overall pairwise Fst = 0.048, Jost's D = 0.133, p < 0.01). Despite the high human migration across the 270km separating the study sites, these results suggest significant restrictions to gene flow against contiguous geospatial transmission of malaria in west Cameroon. Clonal infections in the highland sites could be driven by lower levels of malaria prevalence and seasonal transmission. How these differences in genetic diversity and complexity affect responses to interventions such as drugs will require further investigations from broader community sampling.
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Affiliation(s)
- Ngoh Ines Atuh
- Department of Biomedical Science, Faculty of Health Science, University of Buea, Buea, Cameroon
- Disease Control and Elimination, Medical Research Council Unit the Gambia at LSHTM. Banjul, The Gambia
| | - Damian Nota Anong
- Department of Microbiology & Parasitology, Faculty of Science, University of Buea, Molyko Buea, Cameroon
| | - Fru-Cho Jerome
- Department of Biomedical Science, Faculty of Health Science, University of Buea, Buea, Cameroon
| | - Eniyou Oriero
- Disease Control and Elimination, Medical Research Council Unit the Gambia at LSHTM. Banjul, The Gambia
| | - Nuredin Ibrahim Mohammed
- Disease Control and Elimination, Medical Research Council Unit the Gambia at LSHTM. Banjul, The Gambia
| | - Umberto D’Alessandro
- Department of Microbiology & Parasitology, Faculty of Science, University of Buea, Molyko Buea, Cameroon
| | - Alfred Amambua-Ngwa
- Disease Control and Elimination, Medical Research Council Unit the Gambia at LSHTM. Banjul, The Gambia
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7
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Wong W, Volkman S, Daniels R, Schaffner S, Sy M, Ndiaye YD, Badiane AS, Deme AB, Diallo MA, Gomis J, Sy N, Ndiaye D, Wirth DF, Hartl DL. R H: a genetic metric for measuring intrahost Plasmodium falciparum relatedness and distinguishing cotransmission from superinfection. PNAS NEXUS 2022; 1:pgac187. [PMID: 36246152 PMCID: PMC9552330 DOI: 10.1093/pnasnexus/pgac187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 09/08/2022] [Indexed: 01/29/2023]
Abstract
Multiple-strain (polygenomic) infections are a ubiquitous feature of Plasmodium falciparum parasite population genetics. Under simple assumptions of superinfection, polygenomic infections are hypothesized to be the result of multiple infectious bites. As a result, polygenomic infections have been used as evidence of repeat exposure and used to derive genetic metrics associated with high transmission intensity. However, not all polygenomic infections are the result of multiple infectious bites. Some result from the transmission of multiple, genetically related strains during a single infectious bite (cotransmission). Superinfection and cotransmission represent two distinct transmission processes, and distinguishing between the two could improve inferences regarding parasite transmission intensity. Here, we describe a new metric, R H, that utilizes the correlation in allelic state (heterozygosity) within polygenomic infections to estimate the likelihood that the observed complexity resulted from either superinfection or cotransmission. R H is flexible and can be applied to any type of genetic data. As a proof of concept, we used R H to quantify polygenomic relatedness and estimate cotransmission and superinfection rates from a set of 1,758 malaria infections genotyped with a 24 single nucleotide polymorphism (SNP) molecular barcode. Contrary to expectation, we found that cotransmission was responsible for a significant fraction of 43% to 53% of the polygenomic infections collected in three distinct epidemiological regions in Senegal. The prediction that polygenomic infections frequently result from cotransmission stresses the need to incorporate estimates of relatedness within polygenomic infections to ensure the accuracy of genomic epidemiology surveillance data for informing public health activities.
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Affiliation(s)
- Wesley Wong
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Sarah Volkman
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
- College of Natural, Behavioral, and Health Sciences, Simmons University, Boston, MA 02115, USA
| | - Rachel Daniels
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Stephen Schaffner
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Mouhamad Sy
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Yaye Die Ndiaye
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Aida S Badiane
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Awa B Deme
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Mamadou Alpha Diallo
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Jules Gomis
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Ngayo Sy
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Daouda Ndiaye
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Daniel L Hartl
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
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8
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Opute AO, Akinkunmi JA, Funsho AO, Obaniyi AK, Anifowoshe AT. Genetic diversity of Plasmodium falciparum isolates in Nigeria. A review. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2022. [DOI: 10.1186/s43042-022-00340-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
The complexity of infection in malaria-endemic areas is exacerbated by the presence of genetically diverse Plasmodium falciparum strains. There is a risk that more virulent or drug-resistant versions of the disease may arise. Therefore, we reviewed most reported molecular markers that have been detailed to date in Nigeria.
Main body of the abstract
In this review, we have summarized the genetic diversity of P. falciparum in Nigeria using the two well-reported genes (msp1 and msp2) as genetic diversity biomarkers. The review includes the findings obtained from research conducted in all major geopolitical regions of the country. We found that MSP-2 infection complexity is generally moderate to high in the North-central region. However, in the South-West, there were several regions where the multiplicity of infection (MOI) was either low or extremely high.
Conclusion
Understanding how Nigeria's malaria situation fits into various reports on P. falciparum genetic variation can improve treatment and immunization options. This review will be helpful for future treatment strategies that would be tailored to the specific needs of Nigeria's malaria-endemic populations.
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Ataba E, Dorkenoo AM, Nguepou CT, Bakai T, Tchadjobo T, Kadzahlo KD, Yakpa K, Atcha-Oubou T. Potential Emergence of Plasmodium Resistance to Artemisinin Induced by the Use of Artemisia annua for Malaria and COVID-19 Prevention in Sub-African Region. Acta Parasitol 2022; 67:55-60. [PMID: 34797496 PMCID: PMC8602884 DOI: 10.1007/s11686-021-00489-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/26/2021] [Indexed: 12/23/2022]
Abstract
Plasmodium resistance to antimalarial drugs is an obstacle to the elimination of malaria in endemic areas. This situation is particularly dramatic for Africa, which accounts for nearly 92% of malaria cases worldwide. Drug pressure has been identified as a key factor in the emergence of antimalarial drug resistance. Indeed, this pressure is favoured by several factors, including the use of counterfeit forms of antimalarials, inadequate prescription controls, poor adherence to treatment regimens, dosing errors, and the increasing use of other forms of unapproved antimalarials. This resistance has led to the replacement of chloroquine (CQ) by artemisinin-based combination therapies (ACTs) which are likely to become ineffective in the coming years due to the uncontrolled use of Artemisia annua in the sub-Saharan African region for malaria prevention and COVID-19. The use of Artemisia annua for the prevention of malaria and COVID-19 could be an important factor in the emergence of resistance to Artemisinin-based combination therapies.
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Affiliation(s)
- Essoham Ataba
- Ecole Supérieure des Techniques Biologiques et Alimentaires (ESTBA) /Unité de Recherche en Immunologie et Immunomodulation (UR2IM), Université de Lomé, Boulevard Eyadema, 01BP 1515 Lomé, Togo
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Ameyo M. Dorkenoo
- Faculté des Sciences de la Santé, Université de Lomé, Boulevard Eyadema, 01BP 1515 Lomé, Togo
| | - Christèle Tchopba Nguepou
- Ecole Supérieure des Techniques Biologiques et Alimentaires (ESTBA) /Unité de Recherche en Immunologie et Immunomodulation (UR2IM), Université de Lomé, Boulevard Eyadema, 01BP 1515 Lomé, Togo
| | - Tchaa Bakai
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Tchassama Tchadjobo
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Komla Dovenè Kadzahlo
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Kossi Yakpa
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Tinah Atcha-Oubou
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
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10
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Lagnika HO, Moussiliou A, Agonhossou R, Sovegnon P, Djihinto OY, Medjigbodo AA, Djossou L, Amoah LE, Ogouyemi-Hounto A, Djogbenou LS. Plasmodium falciparum msp1 and msp2 genetic diversity in parasites isolated from symptomatic and asymptomatic malaria subjects in the South of Benin. Parasitol Res 2022; 121:167-175. [PMID: 34993632 DOI: 10.1007/s00436-021-07399-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022]
Abstract
Symptomatic and asymptomatic malaria patients are considered as the reservoirs of human Plasmodium. In the present study, we have evaluated the Plasmodium falciparum merozoite surface protein-1 (Pfmsp1) and protein-2 (Pfmsp2) genetic diversity among the symptomatic and asymptomatic malaria infection from health facilities in Cotonou, Benin Republic. A cross-sectional study recruited 158 individuals, including 77 from the asymptomatic and 81 from the symptomatic groups. The parasites were genotyped using Nested Polymerase Chain Reaction. Samples identified as Plasmodium falciparum were genotyped for their genetic diversity. No significant difference was observed in the overall multiplicity of infection (MOI) between the asymptomatic and symptomatic groups. In the symptomatic group, the overall frequency of K1, MAD20, and RO33 allelic family was more predominant (98.5%) followed by 3D7 (87.3%) and FC27 (83.1%). However, in asymptomatic group, the K1 alleles were the most prevalent (100%) followed by FC27 (89.9%), 3D7 (76.8%), MAD20 (60.5%), and RO33 (35.5%). The frequency of multiple allelic types (K1+MAD20+RO33) at the Pfmsp1 loci in the symptomatic infections was significantly higher when compared to that of the asymptomatic ones (97% vs. 34%, p < 0.05), whereas no difference was observed in the frequency of multiple allelic types (3D7 and FC27) at the Pfmsp2 loci between the two groups. The high presence of msp1 multiple infections in the symptomatic group compared to asymptomatic ones suggests an association between the genetic diversity and the onset of malaria symptoms. These data can provide valuable information in the development of a vaccine that could reduce the symptomatic disease.
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Affiliation(s)
- Hamirath Odée Lagnika
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Azizath Moussiliou
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Romuald Agonhossou
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Pierre Sovegnon
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Oswald Yédjinnavênan Djihinto
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Adandé Assogba Medjigbodo
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Laurette Djossou
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Linda Eva Amoah
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | | | - Luc Salako Djogbenou
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin.
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin.
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11
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Whitlock AOB, Juliano JJ, Mideo N. Immune selection suppresses the emergence of drug resistance in malaria parasites but facilitates its spread. PLoS Comput Biol 2021; 17:e1008577. [PMID: 34280179 PMCID: PMC8321109 DOI: 10.1371/journal.pcbi.1008577] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 07/29/2021] [Accepted: 06/04/2021] [Indexed: 12/23/2022] Open
Abstract
Although drug resistance in Plasmodium falciparum typically evolves in regions of low transmission, resistance spreads readily following introduction to regions with a heavier disease burden. This suggests that the origin and the spread of resistance are governed by different processes, and that high transmission intensity specifically impedes the origin. Factors associated with high transmission, such as highly immune hosts and competition within genetically diverse infections, are associated with suppression of resistant lineages within hosts. However, interactions between these factors have rarely been investigated and the specific relationship between adaptive immunity and selection for resistance has not been explored. Here, we developed a multiscale, agent-based model of Plasmodium parasites, hosts, and vectors to examine how host and parasite dynamics shape the evolution of resistance in populations with different transmission intensities. We found that selection for antigenic novelty (“immune selection”) suppressed the evolution of resistance in high transmission settings. We show that high levels of population immunity increased the strength of immune selection relative to selection for resistance. As a result, immune selection delayed the evolution of resistance in high transmission populations by allowing novel, sensitive lineages to remain in circulation at the expense of the spread of a resistant lineage. In contrast, in low transmission settings, we observed that resistant strains were able to sweep to high population prevalence without interference. Additionally, we found that the relationship between immune selection and resistance changed when resistance was widespread. Once resistance was common enough to be found on many antigenic backgrounds, immune selection stably maintained resistant parasites in the population by allowing them to proliferate, even in untreated hosts, when resistance was linked to a novel epitope. Our results suggest that immune selection plays a role in the global pattern of resistance evolution. Drug resistance in the malaria parasite, Plasmodium falciparum, presents an ongoing public health challenge, but aspects of its evolution are poorly understood. Although antimalarial resistance is common worldwide, it can typically be traced to just a handful of evolutionary origins. Counterintuitively, although Sub Saharan Africa bears 90% of the global malaria burden, resistance typically originates in regions where transmission intensity is low. In high transmission regions, infections are genetically diverse, and hosts have significant standing adaptive immunity, both of which are known to suppress the frequency of resistance within infections. However, interactions between immune-driven selection, transmission intensity, and resistance have not been investigated. Using a multiscale, agent-based model, we found that high transmission intensity slowed the evolution of resistance via its effect on host population immunity. High host immunity strengthened selection for antigenic novelty, interfering with selection for resistance and allowing sensitive lineages to suppress resistant lineages in untreated hosts. However, once resistance was common in the circulating parasite population, immune selection maintained it in the population at a high prevalence. Our findings provide a novel explanation for observations about the origin of resistance and suggest that adaptive immunity is a critical component of selection.
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Affiliation(s)
| | - Jonathan J. Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Nicole Mideo
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Canada
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12
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Mitchell RM, Zhou Z, Sheth M, Sergent S, Frace M, Nayak V, Hu B, Gimnig J, Ter Kuile F, Lindblade K, Slutsker L, Hamel MJ, Desai M, Otieno K, Kariuki S, Vigfusson Y, Shi YP. Development of a new barcode-based, multiplex-PCR, next-generation-sequencing assay and data processing and analytical pipeline for multiplicity of infection detection of Plasmodium falciparum. Malar J 2021; 20:92. [PMID: 33593329 PMCID: PMC7885407 DOI: 10.1186/s12936-021-03624-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 02/04/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Simultaneous infection with multiple malaria parasite strains is common in high transmission areas. Quantifying the number of strains per host, or the multiplicity of infection (MOI), provides additional parasite indices for assessing transmission levels but it is challenging to measure accurately with current tools. This paper presents new laboratory and analytical methods for estimating the MOI of Plasmodium falciparum. METHODS Based on 24 single nucleotide polymorphisms (SNPs) previously identified as stable, unlinked targets across 12 of the 14 chromosomes within P. falciparum genome, three multiplex PCRs of short target regions and subsequent next generation sequencing (NGS) of the amplicons were developed. A bioinformatics pipeline including B4Screening pathway removed spurious amplicons to ensure consistent frequency calls at each SNP location, compiled amplicons by SNP site diversity, and performed algorithmic haplotype and strain reconstruction. The pipeline was validated by 108 samples generated from cultured-laboratory strain mixtures in different proportions and concentrations, with and without pre-amplification, and using whole blood and dried blood spots (DBS). The pipeline was applied to 273 smear-positive samples from surveys conducted in western Kenya, then providing results into StrainRecon Thresholding for Infection Multiplicity (STIM), a novel MOI estimator. RESULTS The 24 barcode SNPs were successfully identified uniformly across the 12 chromosomes of P. falciparum in a sample using the pipeline. Pre-amplification and parasite concentration, while non-linearly associated with SNP read depth, did not influence the SNP frequency calls. Based on consistent SNP frequency calls at targeted locations, the algorithmic strain reconstruction for each laboratory-mixed sample had 98.5% accuracy in dominant strains. STIM detected up to 5 strains in field samples from western Kenya and showed declining MOI over time (q < 0.02), from 4.32 strains per infected person in 1996 to 4.01, 3.56 and 3.35 in 2001, 2007 and 2012, and a reduction in the proportion of samples with 5 strains from 57% in 1996 to 18% in 2012. CONCLUSION The combined approach of new multiplex PCRs and NGS, the unique bioinformatics pipeline and STIM could identify 24 barcode SNPs of P. falciparum correctly and consistently. The methodology could be applied to field samples to reliably measure temporal changes in MOI.
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Affiliation(s)
- Rebecca M Mitchell
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
- Department of Computer Science, Emory University, Atlanta, USA
- School of Nursing, Emory University, Atlanta, USA
| | - Zhiyong Zhou
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Mili Sheth
- Biotechnology Core Facility Branch, Division of Scientific Resources, CDC, Atlanta, USA
| | - Sheila Sergent
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Michael Frace
- Biotechnology Core Facility Branch, Division of Scientific Resources, CDC, Atlanta, USA
| | - Vishal Nayak
- Office of Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC, Atlanta, USA
| | - Bin Hu
- Office of Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC, Atlanta, USA
| | - John Gimnig
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | | | - Kim Lindblade
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Laurence Slutsker
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Mary J Hamel
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Meghna Desai
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Kephas Otieno
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Simon Kariuki
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Ymir Vigfusson
- Department of Computer Science, Emory University, Atlanta, USA.
| | - Ya Ping Shi
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA.
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13
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Sondo P, Bihoun B, Tahita MC, Derra K, Rouamba T, Nakanabo Diallo S, Kazienga A, Ilboudo H, Valea I, Tarnagda Z, Sorgho H, Lefèvre T, Tinto H. Plasmodium falciparum gametocyte carriage in symptomatic patients shows significant association with genetically diverse infections, anaemia, and asexual stage density. Malar J 2021; 20:31. [PMID: 33413393 PMCID: PMC7791700 DOI: 10.1186/s12936-020-03559-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/18/2020] [Indexed: 11/17/2022] Open
Abstract
Background Multi-genotype malaria infections are frequent in endemic area, and people commonly harbour several genetically distinct Plasmodium falciparum variants. The influence of genetic multiplicity and whether some specific genetic variants are more or less likely to invest into gametocyte production is not clearly understood. This study explored host and parasite-related risk factors for gametocyte carriage, and the extent to which some specific P. falciparum genetic variants are associated with gametocyte carriage. Methods Gametocytes and asexual forms were detected by light microscopy on thick smears collected between 2010 and 2012 in Nanoro, Burkina Faso. Merozoite surface protein 1 and 2 were genotyped by nested PCR on clinical samples. Associations between gametocyte carriage and factors, including multiplicity of infection, parasite density, patient age, gender, haemoglobin (Hb) level, and body temperature were assessed. The relationship between the presence of a particular msp1 and msp2 genetic variants and gametocyte carriage was also explored. Results Of the 724 samples positive to P. falciparum and successfully genotyped, gametocytes were found in 48 samples (6.63%). There was no effect of patient gender, age and body temperature on gametocyte carriage. However, the probability of gametocyte carriage significantly increased with increasing values of multiplicity of infection (MOI). Furthermore, there was a negative association between parasite density and gametocyte carriage. MOI decreased with parasite density in gametocyte-negative patients, but increased in gametocyte carriers. The probability of gametocyte carriage decreased with Hb level. Finally, the genetic composition of the infection influenced gametocyte carriage. In particular, the presence of RO33 increased the odds of developing gametocytes by 2 while the other allelic families K1, MAD20, FC27, and 3D7 had no significant impact on the occurrence of gametocytes in infected patients. Conclusion This study provides insight into potential factors influencing gametocyte production in symptomatic patients. The findings contribute to enhance understanding of risk factors associated with gametocyte carriage in humans. Trial registration NCT01232530.
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Affiliation(s)
- Paul Sondo
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso.
| | - Biebo Bihoun
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso
| | - Marc Christian Tahita
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso
| | - Karim Derra
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso
| | - Toussaint Rouamba
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso
| | - Seydou Nakanabo Diallo
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso.,Institut National de Santé Publique/Centre Muraz de Bobo-Dioulasso, Bobo-Dioulasso, Burkina Faso
| | - Adama Kazienga
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso
| | - Hamidou Ilboudo
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso
| | - Innocent Valea
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso.,Institut National de Santé Publique/Centre Muraz de Bobo-Dioulasso, Bobo-Dioulasso, Burkina Faso
| | - Zekiba Tarnagda
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso
| | - Hermann Sorgho
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso
| | - Thierry Lefèvre
- Laboratoire Mixte International Sur Les Vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso.,MIVEGEC, Université de Montpellier, IRD, CNRS, Montpellier, France.,Centre de Recherche en Écologie Et Évolution de La Santé (CREES), Montpellier, France
| | - Halidou Tinto
- Institut de Recherche en Sciences de La Santé/ Clinical Research Unit of Nanoro (IRSS-URCN), Nanoro, Burkina Faso
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14
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Eldh M, Hammar U, Arnot D, Beck HP, Garcia A, Liljander A, Mercereau-Puijalon O, Migot-Nabias F, Mueller I, Ntoumi F, Ross A, Smith T, Sondén K, Vafa Homann M, Yman V, Felger I, Färnert A. Multiplicity of Asymptomatic Plasmodium falciparum Infections and Risk of Clinical Malaria: A Systematic Review and Pooled Analysis of Individual Participant Data. J Infect Dis 2020; 221:775-785. [PMID: 31585009 PMCID: PMC7026891 DOI: 10.1093/infdis/jiz510] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/01/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The malaria parasite Plasmodium falciparum holds an extensive genetic polymorphism. In this pooled analysis, we investigate how the multiplicity in asymptomatic P. falciparum infections-that is, the number of coinfecting clones-affects the subsequent risk of clinical malaria in populations living under different levels of transmission. METHODS A systematic search of the literature was performed to identify studies in which P. falciparum infections were genotyped in asymptomatic individuals who were followed up prospectively regarding the incidence of clinical malaria. Individual participant data were pooled from 15 studies (n = 3736 individuals). RESULTS Multiclonal asymptomatic infections were associated with a somewhat increased subsequent risk of clinical malaria in the youngest children, followed by an initial declining risk with age irrespective of transmission intensity. At approximately 5 years of age, the risk continued the gradual decline with age in high-transmission settings. However, in older children in moderate-, low-, and seasonal-transmission settings, multiclonal infections were either not significantly associated with the risk of subsequent febrile malaria or were associated with an increased risk. CONCLUSIONS The number of clones in asymptomatic P. falciparum infections is associated with different risks of subsequent clinical malaria depending on age and transmission intensity.
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Affiliation(s)
- Martina Eldh
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Ulf Hammar
- Unit of Biostatistics, Department of Epidemiology, Institute for Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - David Arnot
- Zhejiang-Edinburgh Institute, Zhejiang University Medical School, International Campus of Zhejiang University, Haining, People's Republic of China
| | - Hans-Peter Beck
- Molecular Diagnostics, Medical Parasitology and Infection Biology, Swiss Tropical Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - André Garcia
- MERIT, IRD, Université Paris 5, Sorbonne Paris Cité, Paris, France.,Cerpage, Cotonou, Bénin
| | - Anne Liljander
- International Livestock Research Institute, Nairobi, Kenya
| | | | | | - Ivo Mueller
- Institut Pasteur, Parasites and Insect Vectors Department, Paris, France
| | - Francine Ntoumi
- Fondation Congolaise pour la Recherche Médicale and Faculty of Sciences and Technology University Marien Ngouabi Brazzaville, Republic of Congo.,Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Amanda Ross
- University of Basel, Basel, Switzerland.,Department of Epidemiology and Public Health, Swiss Tropical Institute, Basel, Switzerland
| | - Thomas Smith
- University of Basel, Basel, Switzerland.,Department of Epidemiology and Public Health, Swiss Tropical Institute, Basel, Switzerland
| | - Klara Sondén
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Manijeh Vafa Homann
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Victor Yman
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Ingrid Felger
- Molecular Diagnostics, Medical Parasitology and Infection Biology, Swiss Tropical Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Anna Färnert
- Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
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15
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Touray AO, Mobegi VA, Wamunyokoli F, Herren JK. Diversity and Multiplicity of P. falciparum infections among asymptomatic school children in Mbita, Western Kenya. Sci Rep 2020; 10:5924. [PMID: 32246127 PMCID: PMC7125209 DOI: 10.1038/s41598-020-62819-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/18/2020] [Indexed: 11/25/2022] Open
Abstract
Multiplicity of infection (MOI) and genetic diversity of P. falciparum infections are important surrogate indicators for assessing malaria transmission intensity in different regions of endemicity. Determination of MOI and diversity of P. falciparum among asymptomatic carriers will enhance our understanding of parasite biology and transmission to mosquito vectors. This study examined the MOI and genetic diversity of P. falciparum parasite populations circulating in Mbita, a region characterized as one of the malaria hotspots in Kenya. The genetic diversity and multiplicity of P. falciparum infections in 95 asymptomatic school children (age 5–15 yrs.) residing in Mbita, western Kenya were assessed using 10 polymorphic microsatellite markers. An average of 79.69% (Range: 54.84–95.74%) of the isolates analysed in this study were polyclonal infections as detected in at least one locus. A high mean MOI of 3.39 (Range: 2.24–4.72) and expected heterozygosity (He) of 0.81 (Range: 0.57–0.95) was reported in the study population. The analysed samples were extensively polyclonal infections leading to circulation of highly genetically diverse parasite populations in the study area. These findings correlated with the expectations of high malaria transmission intensity despite scaling up malaria interventions in the area thereby indicating the need for a robust malaria interventions particularly against asymptomatic carriers in order to attain elimination in the region.
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Affiliation(s)
- Abdoulie O Touray
- Department of Molecular Biology and Biotechnology, Institute of Basic Sciences, Technology and Innovation, Pan African University (PAUSTI), Nairobi, Kenya. .,International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya.
| | - Victor A Mobegi
- Department of Biochemistry, School of Medicine, University of Nairobi, Nairobi, Kenya.
| | - Fred Wamunyokoli
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya
| | - Jeremy K Herren
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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16
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Impact of an Irrigation Dam on the Transmission and Diversity of Plasmodium falciparum in a Seasonal Malaria Transmission Area of Northern Ghana. J Trop Med 2020; 2020:1386587. [PMID: 32308690 PMCID: PMC7155757 DOI: 10.1155/2020/1386587] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 02/14/2020] [Indexed: 01/13/2023] Open
Abstract
Water bodies such as dams are known to alter the local transmission patterns of a number of infectious diseases, especially those transmitted by insects and other arthropod vectors. The impact of an irrigation dam on submicroscopic asexual parasite carriage in individuals living in a seasonal malaria transmission area of northern Ghana was investigated. A total of 288 archived DNA samples from two cross-sectional surveys in two communities in the Bongo District of Northern Ghana were analysed. Parasite density was determined by light microscopy and PCR, and parasite diversity was assessed by genotyping of the polymorphic Plasmodium falciparum msp2 block-3 region. Submicroscopic parasitaemia was estimated as the proportional difference between positive samples identified by PCR and microscopy. Dry season submicroscopic parasite prevalence was significantly higher (71.0%, p=0.013) at the dam site compared with the nondam site (49.2%). Similarly, wet season submicroscopic parasite prevalence was significantly higher at the dam site (54.5%, p=0.008) compared with the nondam site (33.0%). There was no difference in parasite density between sites in the dry season (p=0.90) and in the wet season (p=0.85). Multiplicity of infection (MOI) based on PCR data was significantly higher at the dam site compared with the nondam site during the dry season (p < 0.0001) but similar between sites during the wet season. MOI at the nondam site was significantly higher in the wet season than in the dry season (2.49, 1.26, p < 0.0001) but similar between seasons at the dam site. Multivariate analysis showed higher odds of carrying submicroscopic parasites at the dam site in both dry season (OR = 7.46, 95% CI = 3.07–18.15) and in wet season (OR = 1.73, 95% CI = 1.04–2.86). The study findings suggest that large water bodies impact year-round carriage of submicroscopic parasites and sustain Plasmodium transmission.
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Mohamed AO, Hussien M, Mohamed A, Suliman A, Elkando NS, Abdelbagi H, Malik EM, Abdelraheem MH, Hamid MMA. Assessment of Plasmodium falciparum drug resistance molecular markers from the Blue Nile State, Southeast Sudan. Malar J 2020; 19:78. [PMID: 32070355 PMCID: PMC7029593 DOI: 10.1186/s12936-020-03165-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/13/2020] [Indexed: 12/03/2022] Open
Abstract
Background Plasmodium falciparum malaria is a public health problem worldwide. Malaria treatment policy has faced periodic changes due to emergence of drug resistant parasites. In Sudan chloroquine has been replaced by artesunate and sulfadoxine/pyrimethamine (AS/SP) in 2005 and to artemether–lumefantrine (AL) in 2017, due to the development of drug resistance. Different molecular markers have been used to monitor the status of drug resistant P. falciparum. This study aimed to determine the frequency of malaria drug resistance molecular markers in Southeast Sudan. Methods The samples of this study were day zero dried blood spot samples collected from efficacy studies in the Blue Nile State from November 2015 to January 2016. A total of 130 samples were amplified and sequenced using illumina Miseq platform. The molecular markers included were Pfcrt, Pfmdr1, Pfdhfr, Pfdhps, Pfk13, exonuclease and artemisinin resistant (ART‐R) genetic background (Pfmdr2, ferroredoxine, Pfcrt and Pfarps10). Results Resistance markers for chloroquine were detected in 25.8% of the samples as mutant haplotype Pfcrt 72-76 CVIET and 21.7% Pfmdr1 86Y. Pfdhfr mutations were detected in codons 51, 59 and 108. The ICNI double-mutant haplotype was the most prevalent (69%). Pfdhps mutations were detected in codons 436, 437, 540, 581 and 613. The SGEGA triple-mutant haplotype was the most prevalent (43%). In Pfdhfr/Pfdhps combined mutation, quintuple mutation ICNI/SGEGA is the most frequent one (29%). Six of the seven treatment failure samples had quintuple mutation and the seventh was quadruple. This was significantly higher from the adequately responsive group (P < 0.01). Pfk13 novel mutations were found in 7 (8.8%) samples, which were not linked to artemisinin resistance. Mutations in ART‐R genetic background genes ranged from zero to 7%. Exonuclease mutation was not detected. Conclusion In this study, moderate resistance to chloroquine and high resistance to SP was observed. Novel mutations of Pfk13 gene not linked to treatment failure were described. There was no resistance to piperaquine the partner drug of dihydroartemisinin/piperaquine (DHA-PPQ).
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Affiliation(s)
- Abdelrahim O Mohamed
- Department of Biochemistry, Faculty of Medicine, University of Khartoum, Khartoum, Sudan.
| | - Maazza Hussien
- Department of Medical Parasitology and Entomology, Faculty of Medical Laboratory Sciences, Al Neelain University, Khartoum, Sudan.,Institute of Endemic Diseases, Medical Campus, University of Khartoum, P. O. Box 102, Khartoum, Sudan
| | - Amal Mohamed
- Department of Accreditation, General Directorate of Quality, Development and Accreditation, Khartoum, Sudan
| | | | - Nuha S Elkando
- State Ministry of Health, Blue Nile State, Damazin, Sudan
| | - Hanadi Abdelbagi
- Institute of Endemic Diseases, Medical Campus, University of Khartoum, P. O. Box 102, Khartoum, Sudan
| | - Elfatih M Malik
- Department of Community Medicine Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Mohammed H Abdelraheem
- Institute of Endemic Diseases, Medical Campus, University of Khartoum, P. O. Box 102, Khartoum, Sudan
| | - Muzamil Mahdi Abdel Hamid
- Department of Medical Parasitology and Entomology, Faculty of Medical Laboratory Sciences, Al Neelain University, Khartoum, Sudan. .,Institute of Endemic Diseases, Medical Campus, University of Khartoum, P. O. Box 102, Khartoum, Sudan.
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18
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Glidden CK, Koehler AV, Hall RS, Saeed MA, Coppo M, Beechler BR, Charleston B, Gasser RB, Jolles AE, Jabbar A. Elucidating cryptic dynamics of Theileria communities in African buffalo using a high-throughput sequencing informatics approach. Ecol Evol 2020; 10:70-80. [PMID: 31988717 PMCID: PMC6972817 DOI: 10.1002/ece3.5758] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/18/2019] [Accepted: 09/20/2019] [Indexed: 12/31/2022] Open
Abstract
Increasing access to next-generation sequencing (NGS) technologies is revolutionizing the life sciences. In disease ecology, NGS-based methods have the potential to provide higher-resolution data on communities of parasites found in individual hosts as well as host populations.Here, we demonstrate how a novel analytical method, utilizing high-throughput sequencing of PCR amplicons, can be used to explore variation in blood-borne parasite (Theileria-Apicomplexa: Piroplasmida) communities of African buffalo at higher resolutions than has been obtained with conventional molecular tools.Results reveal temporal patterns of synchronized and opposite fluctuations of prevalence and relative abundance of Theileria spp. within the host population, suggesting heterogeneous transmission across taxa. Furthermore, we show that the community composition of Theileria spp. and their subtypes varies considerably between buffalo, with differences in composition reflected in mean and variance of overall parasitemia, thereby showing potential to elucidate previously unexplained contrasts in infection outcomes for host individuals.Importantly, our methods are generalizable as they can be utilized to describe blood-borne parasite communities in any host species. Furthermore, our methodological framework can be adapted to any parasite system given the appropriate genetic marker.The findings of this study demonstrate how a novel NGS-based analytical approach can provide fine-scale, quantitative data, unlocking opportunities for discovery in disease ecology.
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Affiliation(s)
| | - Anson V. Koehler
- Department of Veterinary BiosciencesMelbourne Veterinary SchoolUniversity of MelbourneWerribeeVic.Australia
| | - Ross S. Hall
- Department of Veterinary BiosciencesMelbourne Veterinary SchoolUniversity of MelbourneWerribeeVic.Australia
| | - Muhammad A. Saeed
- Department of Veterinary BiosciencesMelbourne Veterinary SchoolUniversity of MelbourneWerribeeVic.Australia
| | - Mauricio Coppo
- Department of Veterinary BiosciencesMelbourne Veterinary SchoolUniversity of MelbourneWerribeeVic.Australia
| | | | | | - Robin B. Gasser
- Carlson College of Veterinary MedicineOregon State UniversityCorvallisORUSA
| | - Anna E. Jolles
- Department of Integrative BiologyOregon State UniversityCorvallisORUSA
- Carlson College of Veterinary MedicineOregon State UniversityCorvallisORUSA
| | - Abdul Jabbar
- Department of Veterinary BiosciencesMelbourne Veterinary SchoolUniversity of MelbourneWerribeeVic.Australia
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Ndiaye T, Sy M, Gaye A, Ndiaye D. Genetic polymorphism of Merozoite Surface Protein 1 (msp1) and 2 (msp2) genes and multiplicity of Plasmodium falciparum infection across various endemic areas in Senegal. Afr Health Sci 2019; 19:2446-2456. [PMID: 32127816 PMCID: PMC7040301 DOI: 10.4314/ahs.v19i3.19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Despite a significant decline in Senegal, malaria remains a burden in various parts of the country. Assessment of multiplicity of Plasmodium falciparum infection and genetic diversity of parasites population could help in monitoring of malaria control. OBJECTIVE To assess genetic diversity and multiplicity of infection in P. falciparum isolates from three areas in Senegal with different malaria transmissions. METHODS 136 blood samples were collected from patients with uncomplicated P. falciparum malaria in Pikine, Kedougou and Thies. Polymorphic loci of msp1 and 2 (Merozoite surface protein-1 and 2) genes were amplified by nested PCR. RESULTS For msp1gene, K1 allelic family was predominant with frequency of 71%. Concerning msp2 gene, IC3D7 allelic family was the most represented with frequency of 83%. Multiclonal isolates found were 36% and 31% for msp1et msp2 genes respectively. The MOI found in all areas was 2.56 and was statistically different between areas (P=0.024). Low to intermediate genetic diversity were found with heterozygosity range (He=0,394-0,637) and low genetic differentiation (Fst msp1= 0.011; Fst msp2=0.017) were observed between P. falciparum population within the country. CONCLUSION Low to moderate genetic diversity of P.falciparum strains and MOI disparities were found in Senegal.
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Affiliation(s)
- Tolla Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mouhamad Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Amy Gaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Daouda Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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20
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Bushman M, Antia R, Udhayakumar V, de Roode JC. Within-host competition can delay evolution of drug resistance in malaria. PLoS Biol 2018; 16:e2005712. [PMID: 30130363 PMCID: PMC6103507 DOI: 10.1371/journal.pbio.2005712] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 07/16/2018] [Indexed: 12/21/2022] Open
Abstract
In the malaria parasite P. falciparum, drug resistance generally evolves first in low-transmission settings, such as Southeast Asia and South America. Resistance takes noticeably longer to appear in the high-transmission settings of sub-Saharan Africa, although it may spread rapidly thereafter. Here, we test the hypothesis that competitive suppression of drug-resistant parasites by drug-sensitive parasites may inhibit evolution of resistance in high-transmission settings, where mixed-strain infections are common. We employ a cross-scale model, which simulates within-host (infection) dynamics and between-host (transmission) dynamics of sensitive and resistant parasites for a population of humans and mosquitoes. Using this model, we examine the effects of transmission intensity, selection pressure, fitness costs of resistance, and cross-reactivity between strains on the establishment and spread of resistant parasites. We find that resistant parasites, introduced into the population at a low frequency, are more likely to go extinct in high-transmission settings, where drug-sensitive competitors and high levels of acquired immunity reduce the absolute fitness of the resistant parasites. Under strong selection from antimalarial drug use, however, resistance spreads faster in high-transmission settings than low-transmission ones. These contrasting results highlight the distinction between establishment and spread of resistance and suggest that the former but not the latter may be inhibited in high-transmission settings. Our results suggest that within-host competition is a key factor shaping the evolution of drug resistance in P. falciparum. The malaria parasite Plasmodium falciparum has evolved resistance to most antimalarial drugs, greatly complicating treatment and control of the disease. Curiously, although sub-Saharan Africa accounts for the majority of the global burden of malaria, the evolution of drug resistance in Africa has been markedly delayed compared to Asia and the Americas. One reason might be that, in a population in which the prevalence of infection is high, a newly emerged drug-resistant strain faces a high risk of extinction due to competition from drug-sensitive parasites that already “occupy” most of the host population. Using a mathematical model, we confirm that drug-resistant parasites face a much greater risk of extinction in a “high-transmission” setting like sub-Saharan Africa than in a “low-transmission” setting like Southeast Asia. However, we also find that when drug-resistant parasites manage to avoid extinction, their subsequent spread may be more rapid in high-transmission settings than in low-transmission settings, especially when selection is strong. These results offer a novel explanation for global patterns of drug resistance evolution in malaria and suggest a new dimension to consider in resistance prevention and containment efforts: namely, the intrinsic favorability of low- and high-transmission settings for establishment and spread of drug resistance.
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Affiliation(s)
- Mary Bushman
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
| | - Rustom Antia
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Jacobus C. de Roode
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
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21
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Boyce RM, Hathaway N, Fulton T, Reyes R, Matte M, Ntaro M, Mulogo E, Waltmann A, Bailey JA, Siedner MJ, Juliano JJ. Reuse of malaria rapid diagnostic tests for amplicon deep sequencing to estimate Plasmodium falciparum transmission intensity in western Uganda. Sci Rep 2018; 8:10159. [PMID: 29977002 PMCID: PMC6033881 DOI: 10.1038/s41598-018-28534-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 06/25/2018] [Indexed: 01/29/2023] Open
Abstract
Molecular techniques are not routinely employed for malaria surveillance, while cross-sectional, community-based parasite surveys require significant resources. Here, we describe a novel use of malaria rapid diagnostic tests (RDTs) collected at a single facility as source material for sequencing to esimtate malaria transmission intensity across a relatively large catchment area. We extracted Plasmodium falciparum DNA from RDTs, then amplified and sequenced a region of the apical membrane antigen 1 (pfama1) using targeted amplicon deep sequencing. We determined the multiplicity of infection (MOI) for each sample and examined associations with demographic, clinical, and spatial factors. We successfully genotyped 223 of 287 (77.7%) of the samples. We demonstrated an inverse relationship between the MOI and elevation with individuals presenting from the highest elevation villages harboring infections approximately half as complex as those from the lowest (MOI 1.85 vs. 3.51, AOR 0.25, 95% CI 0.09-0.65, p = 0.004). This study demonstrates the feasibility and validity of using routinely-collected RDTs for molecular surveillance of malaria and has real-world utility, especially as the cost of high-throughpout sequencing continues to decline.
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Affiliation(s)
- Ross M Boyce
- Division of Infectious Diseases, University of North Carolina at Chapel Hill, 130 Mason Farm Road, Chapel Hill, 27599, USA.
| | - Nick Hathaway
- Program in Bioinformatics and Integrative Biology, University of Massachusetts, 368 Plantation St., Worcester, Massachusetts, 01605, USA
| | - Travis Fulton
- Division of Epidemiology, University of North Carolina at Chapel Hill Gillings School of Global Public Health, 135 Dauer Drive, Chapel Hill, 27599, USA
| | - Raquel Reyes
- Division of General Medicine & Clinical Epidemiology, University of North Carolina at Chapel Hill, 5039 Old Clinic Building, CB 7110, Chapel Hill, 27599, USA
| | - Michael Matte
- Department of Community Health, Mbarara University of Science & Technology, P.O. Box 1410, Mbarara, Uganda
| | - Moses Ntaro
- Department of Community Health, Mbarara University of Science & Technology, P.O. Box 1410, Mbarara, Uganda
| | - Edgar Mulogo
- Department of Community Health, Mbarara University of Science & Technology, P.O. Box 1410, Mbarara, Uganda
| | - Andreea Waltmann
- Division of Infectious Diseases, University of North Carolina at Chapel Hill, 130 Mason Farm Road, Chapel Hill, 27599, USA
| | - Jeffrey A Bailey
- Program in Bioinformatics and Integrative Biology, University of Massachusetts, 368 Plantation St., Worcester, Massachusetts, 01605, USA
| | - Mark J Siedner
- Department of Medicine, Harvard Medical School and Massachusetts General Hospital, 125 Nashua Street, Suite 722, Boston, 02114, USA
| | - Jonathan J Juliano
- Division of Infectious Diseases, University of North Carolina at Chapel Hill, 130 Mason Farm Road, Chapel Hill, 27599, USA.,Division of Epidemiology, University of North Carolina at Chapel Hill Gillings School of Global Public Health, 135 Dauer Drive, Chapel Hill, 27599, USA.,Curriculum in Genetics and Microbiology, University of North Carolina at Chapel Hill, 321 South Columbia Street, Chapel Hill, NC, 27516, USA
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22
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Grignard L, Gonçalves BP, Early AM, Daniels RF, Tiono AB, Guelbéogo WM, Ouédraogo A, van Veen EM, Lanke K, Diarra A, Nebie I, Sirima SB, Targett GA, Volkman SK, Neafsey DE, Wirth DF, Bousema T, Drakeley C. Transmission of molecularly undetectable circulating parasite clones leads to high infection complexity in mosquitoes post feeding. Int J Parasitol 2018; 48:671-677. [PMID: 29738740 PMCID: PMC6018601 DOI: 10.1016/j.ijpara.2018.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/04/2018] [Accepted: 02/26/2018] [Indexed: 11/24/2022]
Abstract
Additional parasite alleles were consistently identified in mosquitoes compared with the human blood sample they had fed on. Assessments of Plasmodium falciparum complexity relying on single time-point collections miss transmissible clones. Low-density gametocyte – producing clones are capable of successfully establishing infections in mosquitoes.
Plasmodium falciparum malaria infections often comprise multiple distinct parasite clones. Few datasets have directly assessed infection complexity in humans and mosquitoes they infect. Examining parasites using molecular tools may provide insights into the selective transmissibility of isolates. Using capillary electrophoresis genotyping and next generation amplicon sequencing, we analysed complexity of parasite infections in human blood and in the midguts of mosquitoes that became infected in membrane feeding experiments using the same blood material in two West African settings. Median numbers of clones in humans and mosquitoes were higher in samples from Burkina Faso (4.5, interquartile range 2–8 for humans; and 2, interquartile range 1–3 for mosquitoes) than in The Gambia (2, interquartile range 1–3 and 1, interquartile range 1–3, for humans and mosquitoes, respectively). Whilst the median number of clones was commonly higher in human blood samples, not all transmitted alleles were detectable in the human peripheral blood. In both study sample sets, additional parasite alleles were identified in mosquitoes compared with the matched human samples (10–88.9% of all clones/feeding assay, n = 73 feeding assays). The results are likely due to preferential amplification of the most abundant clones in peripheral blood but confirm the presence of low density clones that produce transmissible sexual stage parasites.
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Affiliation(s)
- Lynn Grignard
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK.
| | - Bronner P Gonçalves
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Rachel F Daniels
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Alfred B Tiono
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Wamdaogo M Guelbéogo
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Alphonse Ouédraogo
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Elke M van Veen
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kjerstin Lanke
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Amidou Diarra
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Issa Nebie
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Sodiomon B Sirima
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Geoff A Targett
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | - Sarah K Volkman
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA; School of Nursing and Health Sciences, Simmons College, Boston, MA, USA
| | | | - Dyann F Wirth
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Teun Bousema
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
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23
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Zhong D, Koepfli C, Cui L, Yan G. Molecular approaches to determine the multiplicity of Plasmodium infections. Malar J 2018; 17:172. [PMID: 29685152 PMCID: PMC5914063 DOI: 10.1186/s12936-018-2322-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/18/2018] [Indexed: 12/26/2022] Open
Abstract
Multiplicity of infection (MOI), also termed complexity of infection (COI), is defined as the number of genetically distinct parasite strains co-infecting a single host, which is an important indicator of malaria epidemiology. PCR-based genotyping often underestimates MOI. Next generation sequencing technologies provide much more accurate and genome-wide characterization of polyclonal infections. However, complete haplotype characterization of multiclonal infections remains a challenge due to PCR artifacts and sequencing errors, and requires efficient computational tools. In this review, the advantages and limitations of current molecular approaches to determine multiplicity of malaria parasite infection are discussed.
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Affiliation(s)
- Daibin Zhong
- Program in Public Health, University of California, Irvine, CA, 92617, USA.
| | - Cristian Koepfli
- Program in Public Health, University of California, Irvine, CA, 92617, USA
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, 92617, USA.
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24
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Modeling the genetic relatedness of Plasmodium falciparum parasites following meiotic recombination and cotransmission. PLoS Comput Biol 2018; 14:e1005923. [PMID: 29315306 PMCID: PMC5777656 DOI: 10.1371/journal.pcbi.1005923] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 01/22/2018] [Accepted: 12/12/2017] [Indexed: 11/26/2022] Open
Abstract
Unlike in most pathogens, multiple-strain (polygenomic) infections of P. falciparum are frequently composed of genetic siblings. These genetic siblings are the result of sexual reproduction and can coinfect the same host when cotransmitted by the same mosquito. The degree with which coinfecting strains are related varies among infections and populations. Because sexual recombination occurs within the mosquito, the relatedness of cotransmitted strains could depend on transmission dynamics, but little is actually known of the factors that influence the relatedness of cotransmitted strains. Part of the uncertainty stems from an incomplete understanding of how within-host and within-vector dynamics affect cotransmission. Cotransmission is difficult to examine experimentally but can be explored using a computational model. We developed a malaria transmission model that simulates sexual reproduction in order to understand what determines the relatedness of cotransmitted strains. This study highlights how the relatedness of cotransmitted strains depends on both within-host and within-vector dynamics including the complexity of infection. We also used our transmission model to analyze the genetic relatedness of polygenomic infections following a series of multiple transmission events and examined the effects of superinfection. Understanding the factors that influence the relatedness of cotransmitted strains could lead to a better understanding of the population-genetic correlates of transmission and therefore be important for public health. Genomic studies of P. falciparum reveal that multi-strain infections can include genetically related strains. P. falciparum must reproduce sexually in the mosquito vector. One consequence of sexual reproduction is that parasites cotransmitted by the same mosquito are related to one another. The degree of genetic relatedness of these parasites can be as great as that of full-siblings. However, our understanding of the cotransmission process is incomplete, and little is known of the role of cotransmission in influencing population genomic processes. To help bridge this gap, we developed a simulation model to determine which of the steps involved in transmission have the greatest impact on the relatedness of parasites cotransmitted by a mosquito vector. The primary goal of this study is to characterize the outcomes of cotransmission following single or multiple transmission events. Our model yields new insights into the cotransmission process, which we believe will be useful for understanding the results from more complicated population models and epidemiological conditions. Such an understanding is important for the use of population genomics to inform public health decisions as well as for understanding of parasite evolution.
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Zhu SJ, Almagro-Garcia J, McVean G. Deconvolution of multiple infections in Plasmodium falciparum from high throughput sequencing data. Bioinformatics 2018; 34:9-15. [PMID: 28961721 PMCID: PMC5870807 DOI: 10.1093/bioinformatics/btx530] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 07/14/2017] [Accepted: 08/21/2017] [Indexed: 12/20/2022] Open
Abstract
Motivation The presence of multiple infecting strains of the malarial parasite Plasmodium falciparum affects key phenotypic traits, including drug resistance and risk of severe disease. Advances in protocols and sequencing technology have made it possible to obtain high-coverage genome-wide sequencing data from blood samples and blood spots taken in the field. However, analyzing and interpreting such data is challenging because of the high rate of multiple infections present. Results We have developed a statistical method and implementation for deconvolving multiple genome sequences present in an individual with mixed infections. The software package DEploid uses haplotype structure within a reference panel of clonal isolates as a prior for haplotypes present in a given sample. It estimates the number of strains, their relative proportions and the haplotypes presented in a sample, allowing researchers to study multiple infection in malaria with an unprecedented level of detail. Availability and implementation The open source implementation DEploid is freely available at https://github.com/mcveanlab/DEploid under the conditions of the GPLv3 license. An R version is available at https://github.com/mcveanlab/DEploid-r. Contact joe.zhu@bdi.ox.ac.uk or gil.mcvean@bdi.ox.ac.uk. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Sha Joe Zhu
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Jacob Almagro-Garcia
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
- Medical Research Council (MRC) Centre for Genomics and Global Health, University of Oxford, Oxford, UK
- Wellcome Trust Sanger Institute, Hinxton, UK
| | - Gil McVean
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
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Mogeni P, Williams TN, Omedo I, Kimani D, Ngoi JM, Mwacharo J, Morter R, Nyundo C, Wambua J, Nyangweso G, Kapulu M, Fegan G, Bejon P. Detecting Malaria Hotspots: A Comparison of Rapid Diagnostic Test, Microscopy, and Polymerase Chain Reaction. J Infect Dis 2017; 216:1091-1098. [PMID: 28973672 PMCID: PMC5853881 DOI: 10.1093/infdis/jix321] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/06/2017] [Indexed: 12/21/2022] Open
Abstract
Background Malaria control strategies need to respond to geographical hotspots of transmission. Detection of hotspots depends on the sensitivity of the diagnostic tool used. Methods We conducted cross-sectional surveys in 3 sites within Kilifi County, Kenya, that had variable transmission intensities. Rapid diagnostic test (RDT), microscopy, and polymerase chain reaction (PCR) were used to detect asymptomatic parasitemia, and hotspots were detected using the spatial scan statistic. Results Eight thousand five hundred eighty-one study participants were surveyed in 3 sites. There were statistically significant malaria hotspots by RDT, microscopy, and PCR for all sites except by microscopy in 1 low transmission site. Pooled data analysis of hotspots by PCR overlapped with hotspots by microscopy at a moderate setting but not at 2 lower transmission settings. However, variations in degree of overlap were noted when data were analyzed by year. Hotspots by RDT were predictive of PCR/microscopy at the moderate setting, but not at the 2 low transmission settings. We observed long-term stability of hotspots by PCR and microscopy but not RDT. Conclusion Malaria control programs may consider PCR testing to guide asymptomatic malaria hotspot detection once the prevalence of infection falls.
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Affiliation(s)
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Faculty of Medicine, Imperial College London
| | - Irene Omedo
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Joyce M Ngoi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Richard Morter
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,The Jenner Institute, Nuffield Department of Medicine, University of Oxford
| | | | | | | | - Melissa Kapulu
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford
| | - Gregory Fegan
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Swansea Trials Unit, Swansea University Medical School, Swansea, United Kingdom
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford
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Pava Z, Handayuni I, Trianty L, Utami RAS, Tirta YK, Puspitasari AM, Burdam F, Kenangalem E, Wirjanata G, Kho S, Trimarsanto H, Anstey N, Poespoprodjo JR, Noviyanti R, Price RN, Marfurt J, Auburn S. Passively versus Actively Detected Malaria: Similar Genetic Diversity but Different Complexity of Infection. Am J Trop Med Hyg 2017; 97:1788-1796. [PMID: 29016343 PMCID: PMC5790166 DOI: 10.4269/ajtmh.17-0364] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The surveillance of malaria is generally undertaken on the assumption that samples passively collected at health facilities are comparable to or representative of the broader Plasmodium reservoir circulating in the community. Further characterization and comparability of the hidden asymptomatic parasite reservoir are needed to inform on the potential impact of sampling bias. This study explores the impact of sampling strategy on molecular surveillance by comparing the genetic make-up of Plasmodium falciparum and Plasmodium vivax isolates collected by passive versus active case detection. Sympatric isolates of P. falciparum and P. vivax were collected from a large community survey and ongoing clinical surveillance studies undertaken in the hypomesoendemic setting of Mimika District (Papua, Indonesia). Plasmodium falciparum isolates were genotyped at nine microsatellite loci and P. vivax at eight loci. Measures of diversity and differentiation were used to compare different patient and parasitological sample groups. The results demonstrated that passively detected cases (symptomatic) had comparable population diversity to those circulating in the community (asymptomatic) in both species. In addition, asymptomatic patent infections were as diverse as subpatent infections. However, a significant difference in multiplicity of infection (MOI) and percentage of polyclonal infections was observed between actively and passively detected P. vivax cases (mean MOI: 1.7 ± 0.7 versus 1.4 ± 1.4, respectively; P = 0.001). The study findings infer that, in hypomesoendemic settings, passive sampling is appropriate for molecular parasite surveillance strategies using the predominant clone in any given infection; however, the findings suggest caution when analyzing complexity of infection. Further evaluation is required in other endemic settings.
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Affiliation(s)
- Zuleima Pava
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Irene Handayuni
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Leily Trianty
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | | | | | | | - Faustina Burdam
- Mimika District Health Authority, Timika, Papua, Indonesia;,Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia;,Maternal and Child Health and Reproductive Health, Department of Public Health, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Enny Kenangalem
- Mimika District Health Authority, Timika, Papua, Indonesia;,Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia
| | - Grennady Wirjanata
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Steven Kho
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | | | - Nicholas Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Jeanne Rini Poespoprodjo
- Mimika District Health Authority, Timika, Papua, Indonesia;,Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Papua, Indonesia;,Maternal and Child Health and Reproductive Health, Department of Public Health, Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | | | - Ric N. Price
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia;,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Jutta Marfurt
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Sarah Auburn
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia;,Address correspondence to Sarah Auburn, Menzies School of Health Research, PO Box 41096, Casuarina, Darwin, NT 0811, Australia. E-mail:
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Okell LC, Griffin JT, Roper C. Mapping sulphadoxine-pyrimethamine-resistant Plasmodium falciparum malaria in infected humans and in parasite populations in Africa. Sci Rep 2017; 7:7389. [PMID: 28785011 PMCID: PMC5547055 DOI: 10.1038/s41598-017-06708-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 06/16/2017] [Indexed: 11/09/2022] Open
Abstract
Intermittent preventive treatment (IPT) with sulphadoxine-pyrimethamine in vulnerable populations reduces malaria morbidity in Africa, but resistance mutations in the parasite dhps gene (combined with dhfr mutations) threaten its efficacy. We update a systematic review to map the prevalence of K540E and A581G mutations in 294 surveys of infected humans across Africa from 2004-present. Interpreting these data is complicated by multiclonal infections in humans, especially in high transmission areas. We extend statistical methods to estimate the frequency, i.e. the proportion of resistant clones in the parasite population at each location, and so standardise for varying transmission levels. Both K540E and A581G mutations increased in prevalence and frequency in 60% of areas after 2008, highlighting the need for ongoing surveillance. Resistance measures within countries were similar within 300 km, suggesting an appropriate spatial scale for surveillance. Spread of the mutations tended to accelerate once their prevalence exceeded 10% (prior to fixation). Frequencies of resistance in parasite populations are the same or lower than prevalence in humans, so more areas would be classified as likely to benefit from IPT if similar frequency thresholds were applied. We propose that the use of resistance frequencies as well as prevalence measures for policy decisions should be evaluated.
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Affiliation(s)
- Lucy C Okell
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
| | - Jamie T Griffin
- School of Mathematical Sciences, Queen Mary University of London, London, UK
| | - Cally Roper
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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Mohammed H, Kassa M, Assefa A, Tadesse M, Kebede A. Genetic polymorphism of Merozoite Surface Protein-2 (MSP-2) in Plasmodium falciparum isolates from Pawe District, North West Ethiopia. PLoS One 2017; 12:e0177559. [PMID: 28542247 PMCID: PMC5438166 DOI: 10.1371/journal.pone.0177559] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 04/28/2017] [Indexed: 12/13/2022] Open
Abstract
Background In malaria endemic regions, Plasmodium falciparum infection is characterized by extensive genetic diversity. Describing this diversity provides important information about the local malaria situation. This study was conducted to evaluate the extent of genetic diversity of P. falciparum in Pawe district, North West Ethiopia, using the highly polymorphic merozoite surface protein 2 gene. Methods Atotal of 92 isolates from patients with uncomplicated P. falciparum attending Pawe Health Centre were collected from September to December 2013. Genomic DNA was extracted using the Chelex method and analyzed by length polymorphism following gel electrophoresis of DNA products from nested PCR of msp2 (block 3), targeting allelic families of FC27 and 3D7/IC. Results There were twenty-two different msp2 alleles, 11 corresponding to the 3D7/ IC and 11 to the FC27 allelic family. The frequency of isolates of the msp2 3D7/IC allelic familywas higher (51%) compared to FC27 (49%). The majority of the isolates (76%) contained multiple infections andthe overall mean multiplicity of infection was 2.8 (CI 95% 2.55–3.03). The heterozygosity index was 0.66 for msp2. There was no statically significant difference in the multiplicity of infection by age or parasite density. Conclusions The results of this study show that P.falciparum polymorphismsare extensive in Northwest Ethiopia and most of the infections are composed of multiple clones.
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Affiliation(s)
- Hussein Mohammed
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
- * E-mail:
| | - Moges Kassa
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Ashenafi Assefa
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Mekonnen Tadesse
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Amha Kebede
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
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Ayanful-Torgby R, Oppong A, Abankwa J, Acquah F, Williamson KC, Amoah LE. Plasmodium falciparum genotype and gametocyte prevalence in children with uncomplicated malaria in coastal Ghana. Malar J 2016; 15:592. [PMID: 27938356 PMCID: PMC5148883 DOI: 10.1186/s12936-016-1640-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 11/25/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum gametocytes are vital to sustaining malaria transmission. Parasite densities, multiplicity of infection as well as asexual genotype are features that have been found to influence gametocyte production. Measurements of the prevalence of Plasmodium sp. gametocytes may serve as a tool to monitor the success of malaria eradication efforts. METHODS Whole blood was collected from 112 children aged between 6 months and 13 years with uncomplicated P. falciparum malaria attending three health facilities in southern Ghana from June to August, 2014 before (day 0) and 4 days after completion of anti-malaria drug treatment (day 7). Malaria parasites were observed by microscopy and polymerase chain reaction (PCR); submicroscopic gametocyte carriage was measured by a Pfs25 (PF3D7_1031000) mRNA real time reverse transcriptase polymerase chain reaction (RT-PCR). Parasite genotyping was performed on gDNA extracted from dried filter paper blood blots by amplification of the polymorphic regions of msp1 (PF3D7_0930300) and msp2 (PF3D7_0206800) using PCR. RESULTS Microscopy estimated 3.1% (3/96) of the total population to carry gametocytes on day 0, which decreased to 2.1% (2/96) on day 7. In contrast, reverse transcriptase-real time PCR (RT-PCR) analysis of a subset of 35 samples estimated submicroscopic gametocyte carriage to be as high as 77% (27/35) using primers specific for Pfs25 (CT < 35) on day 0 and by day 7 this only declined to 60% (21/35). Genotyping the msp2 gene identified higher levels of MOI than the msp1 gene. CONCLUSIONS Although below detection by microscopy, gametocyte prevalence at submicroscopic levels are high in this region and emphasize the need for more effective elimination approaches like the development of transmission-blocking vaccines and safer gametocytocidal drugs.
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Affiliation(s)
- Ruth Ayanful-Torgby
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Akua Oppong
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joana Abankwa
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Festus Acquah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | | | - Linda Eva Amoah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
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Muhindo Mavoko H, Kalabuanga M, Delgado-Ratto C, Maketa V, Mukele R, Fungula B, Inocêncio da Luz R, Rosanas-Urgell A, Lutumba P, Van geertruyden JP. Uncomplicated Clinical Malaria Features, the Efficacy of Artesunate-Amodiaquine and Their Relation with Multiplicity of Infection in the Democratic Republic of Congo. PLoS One 2016; 11:e0157074. [PMID: 27280792 PMCID: PMC4900589 DOI: 10.1371/journal.pone.0157074] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 05/24/2016] [Indexed: 02/03/2023] Open
Abstract
Background In the Democratic Republic of Congo, artesunate-amodiaquine (ASAQ) is the first-line medication recommended for uncomplicated malaria treatment. We conducted a study in Kinshasa to describe the clinical features of the disease and assess the efficacy of ASAQ and its impact on the multiplicity of infection in children with uncomplicated malaria. Methods Children aged 12 to 59 months with uncomplicated P. falciparum malaria were treated with ASAQ and followed up passively for 42 days. To distinguish new infections from recrudescent parasites, samples were genotyped using a stepwise strategy with three molecular markers (GLURP, MSP2 and MSP1). We then assessed PCR-corrected and -uncorrected day-42 cure rates and multiplicity of infection (MOI). Results In total, 2,796 patients were screened and 865 enrolled in the study. Clinical features were characterized by history of fever (100%), coryza (59.9%) and weakness (59.4%). The crude and PCR-corrected efficacies of ASAQ were 55.3% (95%CI: 51.8–58.8) and 92.8% (95%CI: 91.0–94.6) respectively, as 83.6% (95%CI: 79.1–87.2) of the recurrences were new infections. Compared to monoclonal infections, polyclonal infections were more frequent at enrollment (88.1%) and in recurrences (80.1%; p = 0.005; OR: 1.8, 95%CI: 1.20–2.8). The median MOI at enrollment (MOI = 3.7; IQR: 0.7–6.7) decreased to 3 (IQR: 1–5) in the recurrent samples (p<0.001). Patients infected with a single haplotype on day 0 had no recrudescence; the risk of recrudescence increased by 28% with each additional haplotype (HR: 1.3, 95%CI: 1.24–1.44). Conclusion The PCR-corrected efficacy of ASAQ at day 42 was 92.8%, but crude efficacy was relatively poor due to high reinfection rates. Treatment outcomes were positively correlated with MOI. Continued monitoring of the efficacy of ACTs—ASAQ, in this case—is paramount. Trial Registration ClinicalTrials.gov NCT01374581
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Affiliation(s)
- Hypolite Muhindo Mavoko
- Tropical Medicine Department, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
- Global Health Institute, University of Antwerp, Antwerp, Belgium
- * E-mail:
| | - Marion Kalabuanga
- Outpatients Department, Lisungi Health Center, Kinshasa, Democratic Republic of Congo
| | | | - Vivi Maketa
- Tropical Medicine Department, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
- Global Health Institute, University of Antwerp, Antwerp, Belgium
| | - Rodin Mukele
- Tropical Medicine Department, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Blaise Fungula
- Outpatients Department, Lisungi Health Center, Kinshasa, Democratic Republic of Congo
| | | | | | - Pascal Lutumba
- Tropical Medicine Department, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
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Kateera F, Nsobya SL, Tukwasibwe S, Mens PF, Hakizimana E, Grobusch MP, Mutesa L, Kumar N, van Vugt M. Malaria case clinical profiles and Plasmodium falciparum parasite genetic diversity: a cross sectional survey at two sites of different malaria transmission intensities in Rwanda. Malar J 2016; 15:237. [PMID: 27113354 PMCID: PMC4845397 DOI: 10.1186/s12936-016-1287-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/13/2016] [Indexed: 11/10/2022] Open
Abstract
Background Malaria remains a public health challenge in sub-Saharan Africa with Plasmodiumfalciparum being the principal cause of malaria disease morbidity and mortality. Plasmodium falciparum virulence is attributed, in part, to its population-level genetic diversity—a characteristic that has yet to be studied in Rwanda. Characterizing P. falciparum molecular epidemiology in an area is needed for a better understand of malaria transmission and to inform choice of malaria control strategies. Methods In this health-facility based survey, malaria case clinical profiles and parasite densities as well as parasite genetic diversity were compared among P.falciparum-infected patients identified at two sites of different malaria transmission intensities in Rwanda. Data on demographics and clinical features and finger-prick blood samples for microscopy and parasite genotyping were collected. Nested PCR was used to genotype msp-2 alleles of FC27 and 3D7. Results Patients’ variables of age group, sex, fever (both by patient report and by measured tympanic temperatures), parasite density, and bed net use were found differentially distributed between the higher endemic (Ruhuha) and lower endemic (Mubuga) sites. Overall multiplicity of P.falciparum infection (MOI) was 1.73 but with mean MOI found to vary significantly between 2.13 at Ruhuha and 1.29 at Mubuga (p < 0.0001). At Ruhuha, expected heterozygosity (EH) for FC27 and 3D7 alleles were 0.62 and 0.49, respectively, whilst at Mubuga, EH for FC27 and 3D7 were 0.26 and 0.28, respectively. Conclusions In this study, a higher geometrical mean parasite counts, more polyclonal infections, higher MOI, and higher allelic frequency were observed at the higher malaria-endemic (Ruhuha) compared to the lower malaria-endemic (Mubuga) area. These differences in malaria risk and MOI should be considered when choosing setting-specific malaria control strategies, assessing p. falciparum associated parameters such as drug resistance, immunity and impact of used interventions, and in proper interpretation of malaria vaccine studies.
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Affiliation(s)
- Fredrick Kateera
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda. .,Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.
| | - Sam L Nsobya
- Molecular Research Laboratory, Infectious Disease Research Collaboration, New Mulago Hospital Complex, PO Box 7051, Kampala, Uganda.,Department of Pathology, School Biomedical Science, College of Health Science, Makerere University, PO Box 7072, Kampala, Uganda
| | - Stephen Tukwasibwe
- Molecular Research Laboratory, Infectious Disease Research Collaboration, New Mulago Hospital Complex, PO Box 7051, Kampala, Uganda
| | - Petra F Mens
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.,Royal Tropical Institute/Koninklijk Instituutvoor de Tropen, KIT Biomedical Research, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands
| | - Emmanuel Hakizimana
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda
| | - Martin P Grobusch
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands
| | - Leon Mutesa
- School of Medicine, College of Medicine and Health Sciences, University of Rwanda, PO Box 3286, Kigali, Rwanda
| | - Nirbhay Kumar
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Vector-Borne Infectious Disease Research Centre, Tulane University, 333 S Liberty Street, Mail code 8317, New Orleans, LA, 70112, USA
| | - Michele van Vugt
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands
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Cook J, Grignard L, Al-Eryani S, Al-Selwei M, Mnzava A, Al-Yarie H, Rand A, Kleinschmidt I, Drakeley C. High heterogeneity of malaria transmission and a large sub-patent and diverse reservoir of infection in Wusab As Safil district, Republic of Yemen. Malar J 2016; 15:193. [PMID: 27059182 PMCID: PMC4826523 DOI: 10.1186/s12936-016-1249-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 03/30/2016] [Indexed: 11/10/2022] Open
Abstract
Background Yemen remains the country with the highest malaria transmission within the Arabian Peninsula and a source of imported cases to neighbouring countries. Methods This study collected samples from individuals resident in a valley in Western Yemen as a baseline to examine infection prevalence for a future trial. As well as rapid diagnostic test (RDT) and microscopy, a filter paper blood spot was collected for molecular and serological analyses. Results Samples were collected from 2261 individuals from 12 clusters across a study area of approximately 100 km2. Plasmodium falciparum infection prevalence was 12.4, 11.1 and 19.6 % by RDT, microscopy and polymerase chain reaction (PCR), respectively. RDT and microscopy did not detect 45 % of infections present, suggesting many infections were low-density. Infection prevalence and seroprevalence were highly heterogeneous between clusters, with evidence of higher exposure in clusters close to the wadi. The mean multiplicity of infection (MOI) was 2.3 and high heterozygosity and allelic richness were detected. Conclusions This highly diverse parasite population suggests a high degree of transmissibility and coupled with the substantial proportion of low-density infections, may pose challenges for malaria control and elimination efforts. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1249-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jackie Cook
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK.
| | - Lynn Grignard
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Samira Al-Eryani
- Department of Medical Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen
| | - Mustafa Al-Selwei
- Malaria Control Programme, Ministry of Public Health and Population, Sana'a, Yemen
| | - Abraham Mnzava
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Hafed Al-Yarie
- Malaria Control Programme, Ministry of Public Health and Population, Sana'a, Yemen
| | - Alison Rand
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Immo Kleinschmidt
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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Cryptosporidium within-host genetic diversity: systematic bibliographical search and narrative overview. Int J Parasitol 2016; 46:465-71. [PMID: 27021167 DOI: 10.1016/j.ijpara.2016.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 02/29/2016] [Accepted: 03/06/2016] [Indexed: 11/21/2022]
Abstract
Knowledge of the within-host genetic diversity of a pathogen often has broad implications for disease management. Cryptosporidium protozoan parasites are among the most common causative agents of infectious diarrhoea. Current limitations of in vitro culture impose the use of uncultured isolates obtained directly from the hosts as operational units of Cryptosporidium genotyping. The validity of this practice is centred on the assumption of genetic homogeneity of the parasite within the host, and genetic studies often take little account of the within-host genetic diversity of Cryptosporidium. Yet, theory and experimental evidence contemplate genetic diversity of Cryptosporidium at the within-host scale, but this diversity is not easily identified by genotyping methods ill-suited for the resolution of DNA mixtures. We performed a systematic bibliographical search of the occurrence of within-host genetic diversity of Cryptosporidium parasites in epidemiological samples, between 2005 and 2015. Our results indicate that genetic diversity at the within-host scale, in the form of mixed species or intra-species diversity, has been identified in a large number (n=55) of epidemiological surveys of cryptosporidiosis in variable proportions, but has often been treated as a secondary finding and not analysed. As in malaria, there are indications that the scale of this diversity varies between geographical regions, perhaps depending on the prevailing transmission pathways. These results provide a significant knowledge base from which to draw alternative population genetic structure models, some of which are discussed in this paper.
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Genetic Polymorphism of msp1 and msp2 in Plasmodium falciparum Isolates from Côte d'Ivoire versus Gabon. J Parasitol Res 2016; 2016:3074803. [PMID: 27110390 PMCID: PMC4823507 DOI: 10.1155/2016/3074803] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/01/2016] [Accepted: 03/07/2016] [Indexed: 11/30/2022] Open
Abstract
Introduction. The characterization of genetic profile of Plasmodium isolates from different areas could help in better strategies for malaria elimination. This study aimed to compare P. falciparum diversity in two African countries. Methods. Isolates collected from 100 and 73 falciparum malaria infections in sites of Côte d'Ivoire (West Africa) and Gabon (Central Africa), respectively, were analyzed by a nested PCR amplification of msp1 and msp2 genes. Results. The K1 allelic family was widespread in Côte d'Ivoire (64.6%) and in Gabon (56.6%). For msp2, the 3D7 alleles were more prevalent (>70% in both countries) compared to FC27 alleles. In Côte d'Ivoire, the frequencies of multiple infections with msp1 (45.1%) and msp2 (40.3%) were higher than those found for isolates from Gabon, that is, 30.2% with msp1 and 31.4% with msp2. The overall complexity of infection was 1.66 (SD = 0.79) in Côte d'Ivoire and 1.58 (SD = 0.83) in Gabon. It decreased with age in Côte d'Ivoire in contrast to Gabon. Conclusion. Differences observed in some allelic families and in complexity profile may suggest an impact of epidemiological facies as well as immunological response on genetic variability of P. falciparum.
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Bushman M, Morton L, Duah N, Quashie N, Abuaku B, Koram KA, Dimbu PR, Plucinski M, Gutman J, Lyaruu P, Kachur SP, de Roode JC, Udhayakumar V. Within-host competition and drug resistance in the human malaria parasite Plasmodium falciparum. Proc Biol Sci 2016; 283:20153038. [PMID: 26984625 PMCID: PMC4810865 DOI: 10.1098/rspb.2015.3038] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 02/16/2016] [Indexed: 11/12/2022] Open
Abstract
Infections with the malaria parasite Plasmodium falciparum typically comprise multiple strains, especially in high-transmission areas where infectious mosquito bites occur frequently. However, little is known about the dynamics of mixed-strain infections, particularly whether strains sharing a host compete or grow independently. Competition between drug-sensitive and drug-resistant strains, if it occurs, could be a crucial determinant of the spread of resistance. We analysed 1341 P. falciparum infections in children from Angola, Ghana and Tanzania and found compelling evidence for competition in mixed-strain infections: overall parasite density did not increase with additional strains, and densities of individual chloroquine-sensitive (CQS) and chloroquine-resistant (CQR) strains were reduced in the presence of competitors. We also found that CQR strains exhibited low densities compared with CQS strains (in the absence of chloroquine), which may underlie observed declines of chloroquine resistance in many countries following retirement of chloroquine as a first-line therapy. Our observations support a key role for within-host competition in the evolution of drug-resistant malaria. Malaria control and resistance-management efforts in high-transmission regions may be significantly aided or hindered by the effects of competition in mixed-strain infections. Consideration of within-host dynamics may spur development of novel strategies to minimize resistance while maximizing the benefits of control measures.
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Affiliation(s)
- Mary Bushman
- Department of Biology, Emory University, Atlanta, GA 30322, USA Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Lindsay Morton
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Nancy Duah
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Neils Quashie
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, Accra, Ghana
| | - Benjamin Abuaku
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Kwadwo A Koram
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | - Mateusz Plucinski
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Julie Gutman
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Peter Lyaruu
- Ifakara Health Institute, Dar es Salaam, Tanzania
| | - S Patrick Kachur
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | | | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
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Mawili-Mboumba DP, Mbondoukwe N, Adande E, Bouyou-Akotet MK. Allelic Diversity of MSP1 Gene in Plasmodium falciparum from Rural and Urban Areas of Gabon. THE KOREAN JOURNAL OF PARASITOLOGY 2015; 53:413-9. [PMID: 26323839 PMCID: PMC4566513 DOI: 10.3347/kjp.2015.53.4.413] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/23/2015] [Accepted: 08/05/2015] [Indexed: 11/23/2022]
Abstract
The present study determined and compared the genetic diversity of Plasmodium falciparum strains infecting children living in 2 areas from Gabon with different malaria endemicity. Blood samples were collected from febrile children from 2008 to 2009 in 2 health centres from rural (Oyem) and urban (Owendo) areas. Genetic diversity was determined in P. falciparum isolates by analyzing the merozoite surface protein-1 (msp1) gene polymorphism using nested-PCR. Overall, 168 children with mild falciparum malaria were included. K1, Ro33, and Mad20 alleles were found in 110 (65.5%), 94 (55.9%), and 35 (20.8%) isolates, respectively, without difference according to the site (P>0.05). Allelic families' frequencies were comparable between children less than 5 years old from the 2 sites; while among the older children the proportions of Ro33 and Mad20 alleles were 1.7 to 2.0 fold higher at Oyem. Thirty-three different alleles were detected, 16 (48.5%) were common to both sites, and 10 out of the 17 specific alleles were found at Oyem. Furthermore, multiple infection carriers were frequent at Oyem (57.7% vs 42.2% at Owendo; P=0.04) where the complexity of infection was of 1.88 (±0.95) higher compared to that found at Owendo (1.55±0.75). Extended genetic diversity of P. falciparum strains infecting Gabonese symptomatic children and high multiplicity of infections were observed in rural area. Alleles common to the 2 sites were frequent; the site-specific alleles predominated in the rural area. Such distribution of the alleles should be taken into accounts when designing MSP1 or MSP2 malaria vaccine.
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Affiliation(s)
- Denise Patricia Mawili-Mboumba
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé. BP4009, Libreville, Gabon
| | - Noé Mbondoukwe
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé. BP4009, Libreville, Gabon
| | - Elvire Adande
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé. BP4009, Libreville, Gabon
| | - Marielle Karine Bouyou-Akotet
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé. BP4009, Libreville, Gabon
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Kouyos RD, Metcalf CJE, Birger R, Klein EY, Abel zur Wiesch P, Ankomah P, Arinaminpathy N, Bogich TL, Bonhoeffer S, Brower C, Chi-Johnston G, Cohen T, Day T, Greenhouse B, Huijben S, Metlay J, Mideo N, Pollitt LC, Read AF, Smith DL, Standley C, Wale N, Grenfell B. The path of least resistance: aggressive or moderate treatment? Proc Biol Sci 2015; 281:20140566. [PMID: 25253451 DOI: 10.1098/rspb.2014.0566] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The evolution of resistance to antimicrobial chemotherapy is a major and growing cause of human mortality and morbidity. Comparatively little attention has been paid to how different patient treatment strategies shape the evolution of resistance. In particular, it is not clear whether treating individual patients aggressively with high drug dosages and long treatment durations, or moderately with low dosages and short durations can better prevent the evolution and spread of drug resistance. Here, we summarize the very limited available empirical evidence across different pathogens and provide a conceptual framework describing the information required to effectively manage drug pressure to minimize resistance evolution.
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Affiliation(s)
- Roger D Kouyos
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zürich, University of Zürich, Zürich, Switzerland
| | - C Jessica E Metcalf
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA Department of Zoology, Oxford University, Oxford, UK
| | - Ruthie Birger
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Eili Y Klein
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA Center for Advanced Modeling, Department of Emergency Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Pia Abel zur Wiesch
- Division of Global Health Equity, Brigham and Women's Hospital and Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA
| | - Peter Ankomah
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Nimalan Arinaminpathy
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Tiffany L Bogich
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | | | - Charles Brower
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA Center for Disease Dynamics, Economics & Policy, Washington, DC, USA
| | - Geoffrey Chi-Johnston
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Ted Cohen
- Division of Global Health Equity, Brigham and Women's Hospital and Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA
| | - Troy Day
- Departments of Mathematics and Biology, Queen's University, Kingston, Ontario, Canada
| | - Bryan Greenhouse
- Department of Medicine, Division of Infectious Diseases, University of California, San Francisco, VA, USA
| | - Silvie Huijben
- Barcelona Centre for International Health Research, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Joshua Metlay
- General Medicine Division, Massachusetts General Hospital, Boston, MA, USA
| | - Nicole Mideo
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Laura C Pollitt
- Centre for Infectious Disease Dynamics, The Pennsylvania State University, University Park, State College, PA, USA Departments of Biology and Entomology, The Pennsylvania State University, University Park, State College, PA, USA Centre for Immunology, Infection and Evolution, University of Edinburgh, Edinburgh, UK
| | - Andrew F Read
- Centre for Infectious Disease Dynamics, The Pennsylvania State University, University Park, State College, PA, USA Departments of Biology and Entomology, The Pennsylvania State University, University Park, State College, PA, USA Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | - David L Smith
- Department of Zoology, Oxford University, Oxford, UK
| | - Claire Standley
- Department of Health Policy, George Washington University, Washington, DC, USA
| | - Nina Wale
- Centre for Infectious Disease Dynamics, The Pennsylvania State University, University Park, State College, PA, USA Departments of Biology and Entomology, The Pennsylvania State University, University Park, State College, PA, USA
| | - Bryan Grenfell
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
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Shanks GD. Historical review: does stress provokePlasmodium falciparumrecrudescence? Trans R Soc Trop Med Hyg 2015; 109:360-5. [DOI: 10.1093/trstmh/trv032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 04/01/2015] [Indexed: 01/13/2023] Open
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Jones S, Grignard L, Nebie I, Chilongola J, Dodoo D, Sauerwein R, Theisen M, Roeffen W, Singh SK, Singh RK, Singh S, Kyei-Baafour E, Tetteh K, Drakeley C, Bousema T. Naturally acquired antibody responses to recombinant Pfs230 and Pfs48/45 transmission blocking vaccine candidates. J Infect 2015; 71:117-27. [PMID: 25869538 DOI: 10.1016/j.jinf.2015.03.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 03/13/2015] [Accepted: 03/28/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Pfs48/45 and Pfs230 are Plasmodium falciparum sexual stage proteins and promising malaria transmission-blocking vaccine candidates. Antibody responses against these proteins may be naturally acquired and target antigens may be under selective pressure. This has consequences for the future evaluation of vaccine immunogenicity and efficacy in populations naturally exposed to malaria. METHODS We determined naturally acquired antibody responses to the recombinant proteins Pfs48/45-10C and Pfs230-230CMB in children from three malaria endemic settings in Ghana, Tanzania and Burkina Faso. We also examined genetic polymorphisms in the P. falciparum gene pfs48/45. RESULTS Antibody prevalence was 1.1-18.2% for 10C and 6.7-18.9% for 230CMB. In Burkina Faso we observed evidence of an age-dependent acquisition pattern for both 10C (p < 0.001) and 230CMB (p = 0.031). Membrane feeding assays on a separate dataset demonstrated an association between functional transmission reducing activity and antibody prevalence for both 10C (p = 0.017) and 230CMB (p = 0.049). 17 single nucleotide polymorphisms were found in pfs48/45 (from 126 samples), with 5 non-synonymous SNPs in the Pfs48/45 10C region. CONCLUSIONS We conclude there are naturally acquired antibody responses to both vaccine candidates which have functional relevance by reducing the transmissibility of infected individuals. We identified genetic polymorphisms, in pfs48/45 which exhibited geographical specificity.
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Affiliation(s)
- Sophie Jones
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Lynn Grignard
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Issa Nebie
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | - Daniel Dodoo
- Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michael Theisen
- Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Copenhagen, Denmark; Centre for Medical Parasitology at Department of International Health, Immunology, and Microbiology, University of Copenhagen, Denmark; Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Will Roeffen
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | | | - Sanjay Singh
- Gennova Bio Pharmaceuticals Limited, Pune, India
| | - Eric Kyei-Baafour
- Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | - Kevin Tetteh
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Chris Drakeley
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom; Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
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COIL: a methodology for evaluating malarial complexity of infection using likelihood from single nucleotide polymorphism data. Malar J 2015; 14:4. [PMID: 25599890 PMCID: PMC4417311 DOI: 10.1186/1475-2875-14-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 12/16/2014] [Indexed: 12/15/2022] Open
Abstract
Background Complex malaria infections are defined as those containing more than one genetically distinct lineage of Plasmodium parasite. Complexity of infection (COI) is a useful parameter to estimate from patient blood samples because it is associated with clinical outcome, epidemiology and disease transmission rate. This manuscript describes a method for estimating COI using likelihood, called COIL, from a panel of bi-allelic genotyping assays. Methods COIL assumes that distinct parasite lineages in complex infections are unrelated and that genotyped loci do not exhibit significant linkage disequilibrium. Using the population minor allele frequency (MAF) of the genotyped loci, COIL uses the binomial distribution to estimate the likelihood of a COI level given the prevalence of observed monomorphic or polymorphic genotypes within each sample. Results COIL reliably estimates COI up to a level of three or five with at least 24 or 96 unlinked genotyped loci, respectively, as determined by in silico simulation and empirical validation. Evaluation of COI levels greater than five in patient samples may require a very large collection of genotype data, making sequencing a more cost-effective approach for evaluating COI under conditions when disease transmission is extremely high. Performance of the method is positively correlated with the MAF of the genotyped loci. COI estimates from existing SNP genotype datasets create a more detailed portrait of disease than analyses based simply on the number of polymorphic genotypes observed within samples. Conclusions The capacity to reliably estimate COI from a genome-wide panel of SNP genotypes provides a potentially more accurate alternative to methods relying on PCR amplification of a small number of loci for estimating COI. This approach will also increase the number of applications of SNP genotype data, providing additional motivation to employ SNP barcodes for studies of disease epidemiology or control measure efficacy. The COIL program is available for download from GitHub, and users may also upload their SNP genotype data to a web interface for simple and efficient determination of sample COI. Electronic supplementary material The online version of this article (doi:10.1186/1475-2875-14-4) contains supplementary material, which is available to authorized users.
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Read AF, Huijben S. Evolutionary biology and the avoidance of antimicrobial resistance. Evol Appl 2015; 2:40-51. [PMID: 25567846 PMCID: PMC3352414 DOI: 10.1111/j.1752-4571.2008.00066.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 12/11/2008] [Indexed: 11/29/2022] Open
Abstract
Evolutionary biologists have largely left the search for solutions to the drug resistance crisis to biomedical scientists, physicians, veterinarians and public health specialists. We believe this is because the vast majority of professional evolutionary biologists consider the evolutionary science of drug resistance to be conceptually uninteresting. Using malaria as case study, we argue that it is not. We review examples of evolutionary thinking that challenge various fallacies dominating antimalarial therapy, and discuss open problems that need evolutionary insight. These problems are unlikely to be resolved by biomedical scientists ungrounded in evolutionary biology. Involvement by evolutionary biologists in the science of drug resistance requires no intellectual compromises: the problems are as conceptually challenging as they are important.
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Affiliation(s)
- Andrew F Read
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park PA, USA
| | - Silvie Huijben
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park PA, USA ; School of Biological Sciences, University of Edinburgh West Mains Road, Edinburgh, UK
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Kay K, Hodel EM, Hastings IM. Improving the role and contribution of pharmacokinetic analyses in antimalarial drug clinical trials. Antimicrob Agents Chemother 2014; 58:5643-9. [PMID: 24982091 PMCID: PMC4187976 DOI: 10.1128/aac.02777-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
It is now World Health Organization (WHO) policy that drug concentrations on day 7 be measured as part of routine assessment in antimalarial drug efficacy trials. The rationale is that this single pharmacological measure serves as a simple and practical predictor of treatment outcome for antimalarial drugs with long half-lives. Herein we review theoretical data and field studies and conclude that the day 7 drug concentration (d7c) actually appears to be a poor predictor of therapeutic outcome. This poor predictive capability combined with the fact that many routine antimalarial trials will have few or no failures means that there appears to be little justification for this WHO recommendation. Pharmacological studies have a huge potential to improve antimalarial dosing, and we propose study designs that use more-focused, sophisticated, and cost-effective ways of generating these data than the mass collection of single d7c concentrations.
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Affiliation(s)
- Katherine Kay
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Eva Maria Hodel
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Ian M Hastings
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Culleton RL, Abkallo HM. Malaria parasite genetics: doing something useful. Parasitol Int 2014; 64:244-53. [PMID: 25073068 DOI: 10.1016/j.parint.2014.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 07/11/2014] [Indexed: 01/15/2023]
Abstract
Genetics has informed almost every aspect of the study of malaria parasites, and remains a key component of much of the research that aims to reduce the burden of the disease they cause. We describe the history of genetic studies of malaria parasites and give an overview of the utility of the discipline to malariology.
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Affiliation(s)
- Richard L Culleton
- Malaria Unit, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
| | - Hussein M Abkallo
- Malaria Unit, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
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Tusting LS, Bousema T, Smith DL, Drakeley C. Measuring changes in Plasmodium falciparum transmission: precision, accuracy and costs of metrics. ADVANCES IN PARASITOLOGY 2014; 84:151-208. [PMID: 24480314 PMCID: PMC4847140 DOI: 10.1016/b978-0-12-800099-1.00003-x] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
As malaria declines in parts of Africa and elsewhere, and as more countries move towards elimination, it is necessary to robustly evaluate the effect of interventions and control programmes on malaria transmission. To help guide the appropriate design of trials to evaluate transmission-reducing interventions, we review 11 metrics of malaria transmission, discussing their accuracy, precision, collection methods and costs and presenting an overall critique. We also review the nonlinear scaling relationships between five metrics of malaria transmission: the entomological inoculation rate, force of infection, sporozoite rate, parasite rate and the basic reproductive number, R0. Our chapter highlights that while the entomological inoculation rate is widely considered the gold standard metric of malaria transmission and may be necessary for measuring changes in transmission in highly endemic areas, it has limited precision and accuracy and more standardised methods for its collection are required. In areas of low transmission, parasite rate, seroconversion rates and molecular metrics including MOI and mFOI may be most appropriate. When assessing a specific intervention, the most relevant effects will be detected by examining the metrics most directly affected by that intervention. Future work should aim to better quantify the precision and accuracy of malaria metrics and to improve methods for their collection.
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Affiliation(s)
- Lucy S Tusting
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Department of Infection and Immunity, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - David L Smith
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA; Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA; Fogarty International Center, NIH, Bethesda, Maryland, USA.
| | - Chris Drakeley
- Department of Infection and Immunity, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Mosha JF, Sturrock HJW, Greenhouse B, Greenwood B, Sutherland CJ, Gadalla N, Atwal S, Drakeley C, Kibiki G, Bousema T, Chandramohan D, Gosling R. Epidemiology of subpatent Plasmodium falciparum infection: implications for detection of hotspots with imperfect diagnostics. Malar J 2013; 12:221. [PMID: 23815811 PMCID: PMC3701503 DOI: 10.1186/1475-2875-12-221] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/26/2013] [Indexed: 01/28/2023] Open
Abstract
Background At the local level, malaria transmission clusters in hotspots, which may be a group of households that experience higher than average exposure to infectious mosquitoes. Active case detection often relying on rapid diagnostic tests for mass screen and treat campaigns has been proposed as a method to detect and treat individuals in hotspots. Data from a cross-sectional survey conducted in north-western Tanzania were used to examine the spatial distribution of Plasmodium falciparum and the relationship between household exposure and parasite density. Methods Dried blood spots were collected from consenting individuals from four villages during a survey conducted in 2010. These were analysed by PCR for the presence of P. falciparum, with the parasite density of positive samples being estimated by quantitative PCR. Household exposure was estimated using the distance-weighted PCR prevalence of infection. Parasite density simulations were used to estimate the proportion of infections that would be treated using a screen and treat approach with rapid diagnostic tests (RDT) compared to targeted mass drug administration (tMDA) and Mass Drug Administration (MDA). Results Polymerase chain reaction PCR analysis revealed that of the 3,057 blood samples analysed, 1,078 were positive. Mean distance-weighted PCR prevalence per household was 34.5%. Parasite density was negatively associated with transmission intensity with the odds of an infection being subpatent increasing with household exposure (OR 1.09 per 1% increase in exposure). Parasite density was also related to age, being highest in children five to ten years old and lowest in those > 40 years. Simulations of different tMDA strategies showed that treating all individuals in households where RDT prevalence was above 20% increased the number of infections that would have been treated from 43 to 55%. However, even with this strategy, 45% of infections remained untreated. Conclusion The negative relationship between household exposure and parasite density suggests that DNA-based detection of parasites is needed to provide adequate sensitivity in hotspots. Targeting MDA only to households with RDT-positive individuals may allow a larger fraction of infections to be treated. These results suggest that community-wide MDA, instead of screen and treat strategies, may be needed to successfully treat the asymptomatic, subpatent parasite reservoir and reduce transmission in similar settings.
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Affiliation(s)
- Jacklin F Mosha
- National Institute for Medical Research, NIMR, Mwanza Medical Research Centre, Mwanza, Tanzania.
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Acquired antibodies to merozoite antigens in children from Uganda with uncomplicated or severe Plasmodium falciparum malaria. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1170-80. [PMID: 23740926 DOI: 10.1128/cvi.00156-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Malaria can present itself as an uncomplicated or severe disease. We have here studied the quantity and quality of antibody responses against merozoite antigens, as well as multiplicity of infection (MOI), in children from Uganda. We found higher levels of IgG antibodies toward erythrocyte-binding antigen EBA181, MSP2 of Plasmodium falciparum 3D7 and FC27 (MSP2-3D7/FC27), and apical membrane antigen 1 (AMA1) in patients with uncomplicated malaria by enzyme-linked immunosorbent assay (ELISA) but no differences against EBA140, EBA175, MSP1, and reticulocyte-binding protein homologues Rh2 and Rh4 or for IgM against MSP2-3D7/FC27.Patients with uncomplicated malaria were also shown to have higher antibody affinities for AMA1 by surface plasmon resonance (SPR). Decreased invasion of two clinical P. falciparum isolates in the presence of patient plasma correlated with lower initial parasitemia in the patients, in contrast to comparisons of parasitemia to ELISA values or antibody affinities, which did not show any correlations. Analysis of the heterogeneity of the infections revealed a higher MOI in patients with uncomplicated disease, with the P. falciparum K1 MSP1 (MSP1-K1) and MSP2-3D7 being the most discriminative allelic markers. Higher MOIs also correlated positively with higher antibody levels in several of the ELISAs. In conclusion, certain antibody responses and MOIs were associated with differences between uncomplicated and severe malaria. When different assays were combined, some antibodies, like those against AMA1, seemed particularly discriminative. However, only decreased invasion correlated with initial parasitemia in the patient, signaling the importance of functional assays in understanding development of immunity against malaria and in evaluating vaccine candidates.
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48
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Agyeman-Budu A, Brown C, Adjei G, Adams M, Dosoo D, Dery D, Wilson M, Asante KP, Greenwood B, Owusu-Agyei S. Trends in multiplicity of Plasmodium falciparum infections among asymptomatic residents in the middle belt of Ghana. Malar J 2013; 12:22. [PMID: 23327681 PMCID: PMC3558338 DOI: 10.1186/1475-2875-12-22] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 01/14/2013] [Indexed: 11/23/2022] Open
Abstract
Background Malaria is the most important cause of mortality and morbidity in children living in the Kintampo districts in the middle part of Ghana. This study has investigated the multiplicity of infection (MOI) within asymptomatic residents of the Kintampo districts, and the influence of age and seasonality on MOI, by studying the distribution of the polymorphic Plasmodium falciparum antigen merozoite surface protein 2 (MSP2). Methods DNA was extracted from an asymptomatic cohort of children and adults infected with P. falciparum during the period November 2003 to October 2004. Polymerase chain reaction was carried out and multiplicity of infection (MOI) was determined. Results Children under 10 years of age had an average MOI of 2.3 while adults 18 years and above had an average MOI of 1.4. Children below five years had high and low average MOIs of 2.8 in the March/April survey and 0.9 in the May/June survey respectively. A similar trend in the monthly distribution of MOI was observed for the entire cohort. IC/3D7 strains outnumbered the FC27 strains throughout the year by a ratio of about 4:1 with the difference between the prevalence of the two strains being least marked in the March/April survey, at the beginning of the rainy season. MOI was not linked to the level of malaria transmission as measured by the entomological inoculation rate. Discussion/conclusion The impact of interventions, introduced since this baseline study was carried out on the parasite diversity of asymptomatic residents will be the subject of further investigations.
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Affiliation(s)
- Akua Agyeman-Budu
- Kintampo Health Research Centre, Ghana Health Service, Ministry of Health, Kintampo, Ghana
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49
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Antao T, Hastings I. Policy options for deploying anti-malarial drugs in endemic countries: a population genetics approach. Malar J 2012; 11:422. [PMID: 23244624 PMCID: PMC3546853 DOI: 10.1186/1475-2875-11-422] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 12/08/2012] [Indexed: 11/30/2022] Open
Abstract
Background Anti-malarial drugs are constantly exposed to the threat of evolving drug resistance so good stewardship of existing therapy is an essential component of public health policy. However, the widespread availability of numerous different drugs through informal providers could undermine official drug deployment policies. A policy of multiple first-line therapy (MFT) is compared with the conventional policy of sequential drug deployment, i.e., where one drug is used until resistance evolves and then replaced by the next drug in the sequence. Methods Population genetic models of drug resistance are used to make the comparison; this methodology explicitly tracks the genetics of drug resistance (including, importantly, recombination in the sexual stage, intrahost dynamics, and direction of linkage disequilibrium). Results A policy of MFT outlasts sequential application providing drug usages are low to moderate, and appears not to drive widespread multi-drug resistance. Inadequate dosing is an even more potent driver of drug resistance than the MFT/sequential policy decision. Conclusions The provision of MFT as a deliberate policy can be encouraged provided overall treatment rates are low or moderate (less than around half of malaria infections are treated) and the ad hoc provision of MFT through the private sector may be tolerated. This must be fully supported by education to ensure people take adequate doses of each of the drugs.
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Affiliation(s)
- Tiago Antao
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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50
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Felger I, Maire M, Bretscher MT, Falk N, Tiaden A, Sama W, Beck HP, Owusu-Agyei S, Smith TA. The dynamics of natural Plasmodium falciparum infections. PLoS One 2012; 7:e45542. [PMID: 23029082 PMCID: PMC3445515 DOI: 10.1371/journal.pone.0045542] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 08/20/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Natural immunity to Plasmodium falciparum has been widely studied, but its effects on parasite dynamics are poorly understood. Acquisition and clearance rates of untreated infections are key elements of the dynamics of malaria, but estimating these parameters is challenging because of frequent super-infection and imperfect detectability of parasites. Consequently, information on effects of host immune status or age on infection dynamics is fragmentary. METHODS An age-stratified cohort of 347 individuals from Northern Ghana was sampled six times at 2 month intervals. High-throughput capillary electrophoresis was used to genotype the msp-2 locus of all P. falciparum infections detected by PCR. Force of infection (FOI) and duration were estimated for each age group using an immigration-death model that allows for imperfect detection of circulating parasites. RESULTS Allowing for imperfect detection substantially increased estimates of FOI and duration. Effects of naturally acquired immunity on the FOI and duration would be reflected in age dependence in these indices, but in our cohort data FOI tended to increase with age in children. Persistence of individual parasite clones was characteristic of all age-groups. Duration peaked in 5-9 year old children (average duration 319 days, 95% confidence interval 318;320). CONCLUSIONS The main age-dependence is on parasite densities, with only small age-variations in the FOI and persistence of infections. This supports the hypothesis that acquired immunity controls transmission mainly by limiting blood-stage parasite densities rather than changing rates of acquisition or clearance of infections.
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Affiliation(s)
- Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Martin Maire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Michael T. Bretscher
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Nicole Falk
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - André Tiaden
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Wilson Sama
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Hans-Peter Beck
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Seth Owusu-Agyei
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Thomas A. Smith
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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