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Ajogbasile FV, Kayode AT, Oluniyi PE, Akano KO, Uwanibe JN, Adegboyega BB, Philip C, John OG, Eromon PJ, Emechebe G, Finimo F, Ogbulafor N, Jiya N, Okafor U, Ambe J, Wammanda RD, Oguche S, Mokuolu OA, Sowunmi A, Folarin OA, Happi CT. Genetic diversity and population structure of Plasmodium falciparum in Nigeria: insights from microsatellite loci analysis. Malar J 2021; 20:236. [PMID: 34039364 PMCID: PMC8152046 DOI: 10.1186/s12936-021-03734-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 04/13/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria remains a public health burden especially in Nigeria. To develop new malaria control and elimination strategies or refine existing ones, understanding parasite population diversity and transmission patterns is crucial. METHODS In this study, characterization of the parasite diversity and structure of Plasmodium falciparum isolates from 633 dried blood spot samples in Nigeria was carried out using 12 microsatellite loci of P. falciparum. These microsatellite loci were amplified via semi-nested polymerase chain reaction (PCR) and fragments were analysed using population genetic tools. RESULTS Estimates of parasite genetic diversity, such as mean number of different alleles (13.52), effective alleles (7.13), allelic richness (11.15) and expected heterozygosity (0.804), were high. Overall linkage disequilibrium was weak (0.006, P < 0.001). Parasite population structure was low (Fst: 0.008-0.105, AMOVA: 0.039). CONCLUSION The high level of parasite genetic diversity and low population structuring in this study suggests that parasite populations circulating in Nigeria are homogenous. However, higher resolution methods, such as the 24 SNP barcode and whole genome sequencing, may capture more specific parasite genetic signatures circulating in the country. The results obtained can be used as a baseline for parasite genetic diversity and structure, aiding in the formulation of appropriate therapeutic and control strategies in Nigeria.
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Affiliation(s)
- Fehintola V Ajogbasile
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Adeyemi T Kayode
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Paul E Oluniyi
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Kazeem O Akano
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Jessica N Uwanibe
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Benjamin B Adegboyega
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria
| | - Courage Philip
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria
| | | | - Philomena J Eromon
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria
| | - George Emechebe
- Department of Paediatrics, Imo State University Teaching Hospital, Orlu, Nigeria
| | - Finimo Finimo
- Department of Paediatrics, Federal Medical Centre, Yenagoa, Nigeria
| | - Nnenna Ogbulafor
- Case Management Unit, National Malaria Elimination Programme, Federal Ministry of Health, Abuja, Nigeria
| | - Nma Jiya
- Department of Paediatrics, Uthman Dan Fodio University, Sokoto, Nigeria
| | - Uche Okafor
- Department of Paediatrics, University of Nigeria Teaching Hospital, University of Nigeria, Nsukka, Nigeria
| | - Jose Ambe
- Department of Paediatrics, University of Maiduguri, Maiduguri, Nigeria
| | | | - Stephen Oguche
- Department of Paediatrics, University of Jos Teaching Hospital, University of Jos, Jos, Nigeria
| | - Olugbenga A Mokuolu
- Department of Paediatrics and Child Health, University of Ilorin, Ilorin, Nigeria
| | - Akintunde Sowunmi
- Institute of Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria.,Department of Pharmacology and Therapeutics, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Onikepe A Folarin
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria.,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria
| | - Christian T Happi
- African Centre of Excellence for Genomics of Infectious Diseases (ACEGID), Redeemer's University, Ede, Nigeria. .,Department of Biological Sciences, Faculty of Natural Sciences, Redeemer's University, Ede, Nigeria.
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Roh ME, Tessema SK, Murphy M, Nhlabathi N, Mkhonta N, Vilakati S, Ntshalintshali N, Saini M, Maphalala G, Chen A, Wilheim J, Prach L, Gosling R, Kunene S, S Hsiang M, Greenhouse B. High Genetic Diversity of Plasmodium falciparum in the Low-Transmission Setting of the Kingdom of Eswatini. J Infect Dis 2020; 220:1346-1354. [PMID: 31190073 PMCID: PMC6743842 DOI: 10.1093/infdis/jiz305] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 06/12/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND To better understand transmission dynamics, we characterized Plasmodium falciparum genetic diversity in Eswatini, where transmission is low and sustained by importation. METHODS Twenty-six P. falciparum microsatellites were genotyped in 66% of confirmed cases (2014-2016; N = 582). Population and within-host diversity were used to characterize differences between imported and locally acquired infections. Logistic regression was used to assess the added value of diversity metrics to classify imported and local infections beyond epidemiology data alone. RESULTS Parasite population in Eswatini was highly diverse (expected heterozygosity [HE] = 0.75) and complex: 67% polyclonal infections, mean multiplicity of infection (MOI) 2.2, and mean within-host infection fixation index (FWS) 0.84. Imported cases had comparable diversity to local cases but exhibited higher MOI (2.4 vs 2.0; P = .004) and lower mean FWS (0.82 vs 0.85; P = .03). Addition of MOI and FWS to multivariate analyses did not increase discrimination between imported and local infections. CONCLUSIONS In contrast to the common perception that P. falciparum diversity declines with decreasing transmission intensity, Eswatini isolates exhibited high parasite diversity consistent with high rates of malaria importation and limited local transmission. Estimates of malaria transmission intensity from genetic data need to consider the effect of importation, especially as countries near elimination.
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Affiliation(s)
- Michelle E Roh
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco.,Department of Epidemiology and Biostatistics, University of California, San Francisco
| | - Sofonias K Tessema
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco
| | - Maxwell Murphy
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco
| | | | | | | | | | - Manik Saini
- Clinton Health Access Initiative, Mbabane, Eswatini
| | | | - Anna Chen
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco
| | - Jordan Wilheim
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco
| | - Lisa Prach
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco
| | - Roly Gosling
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco.,Department of Epidemiology and Biostatistics, University of California, San Francisco
| | | | - Michelle S Hsiang
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco.,Department of Pediatrics, University of California, San Francisco.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas
| | - Bryan Greenhouse
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California, San Francisco.,Chan Zuckerberg Biohub, San Francisco, California
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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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4
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Vardo-Zalik AM, Zhou G, Zhong D, Afrane YA, Githeko AK, Yan G. Alterations in Plasmodium falciparum genetic structure two years after increased malaria control efforts in western Kenya. Am J Trop Med Hyg 2013; 88:29-36. [PMID: 23166196 PMCID: PMC3541741 DOI: 10.4269/ajtmh.2012.12-0308] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 10/08/2012] [Indexed: 02/02/2023] Open
Abstract
The impact of malaria intervention measures (insecticide-treated net use and artemisinin combination therapy) on malaria genetics was investigated at two sites in western Kenya: an endemic lowland and an epidemic highland. The genetic structure of the parasite population was assessed by using microsatellites, and the prevalence of drug-resistant mutations was examined by using the polymerase chain reaction-restriction fragment length polymorphism method. Two years after intervention, genetic diversity remained high in both populations. A significant decrease in the prevalence of quintuple mutations conferring resistance to sulfadoxine-pyrimethamine was detected in both populations, but the mutation prevalence at codon 1246 of the Plasmodium falciparum multidrug resistance 1 gene had increased in the highland population. The decrease in sulfadoxine-pyrimethamine-resistant mutants is encouraging, but the increase in P. falciparum multidrug resistance 1 gene mutations is worrisome because these mutations are linked to resistance to other antimalarial drugs. In addition, the high level of genetic diversity observed after intervention suggests transmission is still high in each population.
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Affiliation(s)
- Anne M Vardo-Zalik
- Program in Public Health, College of Health Sciences, University of California Irvine, Irvine, California, USA.
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5
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Population genetics of Schistosoma haematobium: development of novel microsatellite markers and their application to schistosomiasis control in Mali. Parasitology 2011; 138:978-94. [PMID: 21679489 DOI: 10.1017/s0031182011000722] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The recent implementation of mass drug administration (MDA) for control of uro-genital schistosomiasis has identified an urgent need for molecular markers to both directly monitor the impact of MDA, for example to distinguish re-infections from uncleared infections, as well as understand aspects of parasite reproduction and gene flow which might predict evolutionary change, such as the development and spread of drug resistance. We report the development of a novel microsatellite tool-kit allowing, for the first time, robust genetic analysis of individual S. haematobium larvae collected directly from infected human hosts. We genotyped the parasite populations of 47 children from 2 schools in the Ségou region of Mali, the first microsatellite study of this highly neglected parasite. There was only limited evidence of population subdivision between individual children or between the two schools, suggesting that few barriers to gene flow exist in this population. Complex relationships between parasite reproductive success, infection intensity and host age and gender were identified. Older children and boys harboured more diverse infections, as measured by the number of unique adult genotypes present. Individual parasite genotypes had variable reproductive success both across hosts, a pre-requisite for evolutionary selection, and, phenotypically, in hosts of different ages and genders. These data serve as a baseline against which to measure the effect of treatment on parasite population genetics in this region of Mali, and the tools developed are suitable to further investigate this important pathogen, and its close relatives, throughout their range.
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6
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Bob NS, Diop BM, Renaud F, Marrama L, Durand P, Tall A, Ka B, Ekala MT, Bouchier C, Mercereau-Puijalon O, Jambou R. Parasite polymorphism and severe malaria in Dakar (Senegal): a West African urban area. PLoS One 2010; 5:e9817. [PMID: 20352101 PMCID: PMC2843705 DOI: 10.1371/journal.pone.0009817] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 02/01/2010] [Indexed: 11/25/2022] Open
Abstract
Background Transmission of malaria in West African urban areas is low and healthcare facilities are well organized. However, malaria mortality remains high. We conducted a survey in Dakar with the general objective to establish who died from severe malaria (SM) in urban areas (particularly looking at the age-groups) and to compare parasite isolates associated with mild or severe malaria. Methodology/Principal Findings The current study included mild- (MM) and severe malaria (SM) cases, treated in dispensaries (n = 2977) and hospitals (n = 104), We analysed Pfdhfr/Pfcrt-exon2 and nine microsatellite loci in 102 matched cases of SM and MM. Half of the malaria cases recorded at the dispensaries and 87% of SM cases referred to hospitals, occurred in adults, although adults only accounted for 26% of all dispensary consultations. This suggests that, in urban settings, whatever the reason for this adult over-representation, health-workers are forced to take care of increasing numbers of malaria cases among adults. Inappropriate self treatment and mutations in genes associated with drug resistance were found associated with SM in adults. SM was also associated with a specific pool of isolates highly polymorphic and different from those associated with MM. Conclusion In this urban setting, adults currently represent one of the major groups of patients attending dispensaries for malaria treatment. For these patients, despite the low level of transmission, SM was associated with a specific and highly polymorphic pool of parasites which may have been selected by inappropriate treatment.
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Affiliation(s)
| | | | | | | | | | - Adama Tall
- Institut Pasteur de Dakar, Dakar, Senegal
| | | | - Marie Therese Ekala
- Institut Pasteur, Immunologie Moléculaire des Parasites, CNRS URA 2581, Paris, France
| | | | | | - Ronan Jambou
- Institut Pasteur de Dakar, Dakar, Senegal
- * E-mail:
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7
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Vardo-Zalik AM. Clonal diversity of a malaria parasite, Plasmodium mexicanum, and its transmission success from its vertebrate-to-insect host. Int J Parasitol 2009; 39:1573-9. [PMID: 19523471 DOI: 10.1016/j.ijpara.2009.05.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 05/13/2009] [Accepted: 05/15/2009] [Indexed: 11/18/2022]
Abstract
Infections of the lizard malaria parasite Plasmodium mexicanum are often genetically complex within their fence lizard host (Sceloporus occidentalis) harbouring two or more clones of parasite. The role of clonal diversity in transmission success was studied for P. mexicanum by feeding its sandfly vectors (Lutzomyia vexator and Lutzomyia stewarti) on experimentally infected lizards. Experimental infections consisted of one, two, three or more clones, assessed using three microsatellite markers. After 5days, vectors were dissected to assess infection status, oocyst burden and genetic composition of the oocysts. A high proportion (92%) of sandflies became infected and carried high oocyst burdens (mean of 56 oocysts) with no influence of clonal diversity on these two measures of transmission success. Gametocytemia was positively correlated with transmission success and the more common vector (L. vexator) developed more oocysts on midguts. A high proportion ( approximately 74%) of all alleles detected in the lizard blood was found in infected vectors. The relative proportion of clones within mixed infections, determined by peak heights on pherograms produced by the genetic analyser instrument, was very similar for the lizard's blood and infections in the vectors. These results demonstrate that P. mexicanum achieves high transmission success, with most clones making the transition from vertebrate-to-insect host, and thus explains in part the high genetic diversity of the parasite among all hosts at the study site.
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Affiliation(s)
- A M Vardo-Zalik
- Program in Public Health, College of Health Sciences, University of California at Irvine, Room 3501 Hewitt Hall, Irvine, CA 92697-4050, USA.
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8
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Bonizzoni M, Afrane Y, Baliraine FN, Amenya DA, Githeko AK, Yan G. Genetic structure of Plasmodium falciparum populations between lowland and highland sites and antimalarial drug resistance in Western Kenya. INFECTION GENETICS AND EVOLUTION 2009; 9:806-12. [PMID: 19398039 DOI: 10.1016/j.meegid.2009.04.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 04/14/2009] [Accepted: 04/15/2009] [Indexed: 10/20/2022]
Abstract
Human travel to malaria endemic lowlands from epidemic highlands has been shown to increase the risk of malaria infections in the highlands. In order to gain insight on the impact of human travel, we examined prevalence, genetic variability and population genetic structure of Plasmodium falciparum in asymptomatic children from one highland site and three surrounding malaria endemic lowland sites in Western Kenya, using multilocus microsatellite genotyping. We further analyzed the frequencies of mutations at the genes conferring resistance to chloroquine and sulfadoxine-pyrimethamine. We found a significant decrease in malaria prevalence in the highland site from 2006 to 2007, 1 year after the introduction of the artemisinin-based combination therapy as first-line treatment for uncomplicated malaria and the scale-up of insecticide-treated bed nets. Population genetic diversity, measured by the number of observed and effective microsatellite alleles and Nei's unbiased genetic diversity, was high and comparable for both highland and lowland populations. Analysis of molecular variance did not detect a significant genetic structure across highland and lowland regions. Similarly, mutations at key antimalarial-resistance codons of the pfcrt, pfmdr1, pfdhfr and pfdhps genes were found at comparable high frequencies in all four sites. High level of gene flow and lack of significant genetic structure in malaria parasites between highland and lowland areas suggest the importance of human travel in shaping parasite population structure.
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Affiliation(s)
- Mariangela Bonizzoni
- Program in Public Health, College of Health Sciences, University of California, Irvine 92697, USA.
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9
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Vardo-Zalik AM, Schall JJ. Clonal diversity alters the infection dynamics of a malaria parasite (Plasmodium mexicanum) in its vertebrate host. Ecology 2009; 90:529-36. [PMID: 19323236 DOI: 10.1890/07-1866.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Ecological and evolutionary theory predicts that genetic diversity of microparasites within infected hosts will influence the parasite replication rate, parasitemia, transmission strategy, and virulence. We manipulated clonal diversity (number of genotypes) of the malaria parasite, Plasmodium mexicanum, in its natural lizard host and measured important features of the infection dynamics, the first such study for any natural Plasmodium-host association. Hosts harboring either a single P. mexicanum clone or various combinations of clones (scored via three microsatellite markers) were established. Production of asexually replicating stages (meronts) and maximal meront parasitemia did not differ by clonal diversity, nor did timing of first production of transmission stages (gametocytes). However, mean rate of gametocyte increase and maximal gametocyte parasitemia were greater for hosts with mixed-clone infections. Characteristics of infections were more variable in hosts with mixed-clone infections than with single-clone infections except for first production of gametocytes. One or more of the parasite reproductive traits were extreme in 20 of 52 hosts with mixed-clone infections. This was not associated with specific clones, but diversity itself. The overall pattern from studies of clonal diversity for human, rodent, and now reptile malaria parasites confirms that the genetic diversity of infections in the vertebrate host is of central importance for the ecology of Plasmodium.
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Affiliation(s)
- Anne M Vardo-Zalik
- Department of Biology, University of Vermont, Burlington, Vermont 05405, USA.
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10
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Clonal diversity within infections and the virulence of a malaria parasite, Plasmodium mexicanum. Parasitology 2008; 135:1363-72. [PMID: 18937882 DOI: 10.1017/s0031182008004964] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Both verbal and mathematical models of parasite virulence predict that genetic diversity of microparasite infections will influence the level of costs suffered by the host. We tested this idea by manipulating the number of co-existing clones of Plasmodium mexicanum in its natural vertebrate host, the fence lizard Sceloporus occidentalis. We established replicate infections of P. mexicanum made up of 1, 2, 3, or >3 clones (scored using 3 microsatellite loci) to observe the influence of clone number on several measures of parasite virulence. Clonal diversity did not affect body growth or production of immature erythrocytes. Blood haemoglobin concentration was highest for the most genetically complex infections (equal to that of non-infected lizards), and blood glucose levels and rate of blood clotting was highest for the most diverse infections (with greater glucose and more rapid clotting than non-infected animals). Neither specific clones nor parasitaemia were associated with virulence. In this first experiment that manipulated the clonal diversity of a natural Plasmodium-host system, the cost of infection with 1 or 2 clones of P. mexicanum was similar to that previously reported for infected lizards, but the most complex infections had either no cost or could be beneficial for the host.
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11
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Susomboon P, Iwagami M, Tangpukdee N, Krusood S, Looareesuwan S, Kano S. Differences in genetic population structures of Plasmodium falciparum isolates from patients along Thai-Myanmar border with severe or uncomplicated malaria. Malar J 2008; 7:212. [PMID: 18937873 PMCID: PMC2576340 DOI: 10.1186/1475-2875-7-212] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Accepted: 10/21/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There have been many reports on the population genetic structures of Plasmodium falciparum from different endemic regions, but few studies have examined the characteristics of isolates from patients with different clinical outcomes. The population genetic structures of P. falciparum isolates from patients with either severe or uncomplicated malaria were examined. METHODS Twelve microsatellite DNA loci from P. falciparum were used to assess the population genetic structures of 50 isolates (i.e., 25 isolates from patients with severe malaria and 25 from patients with uncomplicated malaria) collected in the Thai-Myanmar border area between 2002 and 2005. RESULTS Genetic diversity and effective population sizes were greater in the uncomplicated malaria group than in the severe malaria group. Evidence of genetic bottlenecks was not observed in either group. Strong linkage disequilibrium was observed in the uncomplicated malaria group. The groups demonstrated significant genetic differentiation (P < 0.05), and allele frequencies for 3 of the 12 microsatellite loci differed significantly between the two groups. CONCLUSION These findings suggest that the genetic structure of P. falciparum populations in patients with severe malaria differs from that in patients with uncomplicated malaria. The microsatellite loci used in this study were presumably unrelated to antigenic features of the parasites, but, these findings suggest that some loci may influence the clinical outcome of malaria.
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Affiliation(s)
- Pannapa Susomboon
- Department of Appropriate Technology Development and Transfer Research Institute, International Medical Center of Japan, Shinjuku, Tokyo, Japan
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12
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dalla Martha RC, Tada MS, Ferreira RGDM, da Silva LHP, Wunderlich G. Microsatellite characterization of Plasmodium falciparum from symptomatic and non-symptomatic infections from the Western Amazon reveals the existence of non-symptomatic infection-associated genotypes. Mem Inst Oswaldo Cruz 2007; 102:293-8. [PMID: 17568933 DOI: 10.1590/s0074-02762007005000044] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 04/18/2007] [Indexed: 01/19/2023] Open
Abstract
In Western Amazon areas with perennial malaria transmission, long term residents frequently develop partial immunity to malarial infection caused either by Plasmodium falciparum or P. vivax, resulting in a considerable number of non-symptomatically infected individuals. For yet unknown reasons, these individuals sporadically develop symptomatic malaria. In order to identify if determined parasite genotypes, defined by a combination of eleven microsatellite markers, were associated to different outcomes--symptomatic or asymptomatic malaria--we analyzed infecting P. falciparum parasites in a suburban riverine population. Despite of detecting a high degree of diversity in the analyzed samples, several microsatellite marker alleles appeared accumulated in parasites from non-symptomatic infections. This result may be interpreted that a number of microsatellites, which are not directly related to antigenic features, could be associated to the outcome of malarial infection. The result may also point to a low frequency of recombinatorial events which otherwise would dissociate genes under strong immune pressure from the relatively neutral microsatellite loci.
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Vardo AM, Schall JJ. Clonal diversity of a lizard malaria parasite, Plasmodium mexicanum, in its vertebrate host, the western fence lizard: role of variation in transmission intensity over time and space. Mol Ecol 2007; 16:2712-20. [PMID: 17594442 DOI: 10.1111/j.1365-294x.2007.03355.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Within the vertebrate host, infections of a malaria parasite (Plasmodium) could include a single genotype of cells (single-clone infections) or two to several genotypes (multiclone infections). Clonal diversity of infection plays an important role in the biology of the parasite, including its life history, virulence, and transmission. We determined the clonal diversity of Plasmodium mexicanum, a lizard malaria parasite at a study region in northern California, using variable microsatellite markers, the first such study for any malaria parasite of lizards or birds (the most common hosts for Plasmodium species). Multiclonal infections are common (50-88% of infections among samples), and measures of genetic diversity for the metapopulation (expected heterozygosity, number of alleles per locus, allele length variation, and effective population size) all indicated a substantial overall genetic diversity. Comparing years with high prevalence (1996-1998 = 25-32% lizards infected), and years with low prevalence (2001-2005 = 6-12%) found fewer alleles in samples taken from the low-prevalence years, but no reduction in overall diversity (H = 0.64-0.90 among loci). In most cases, rare alleles appeared to be lost as prevalence declined. For sites chronically experiencing low transmission intensity (prevalence approximately 1%), overall diversity was also high (H = 0.79-0.91), but there were fewer multiclonal infections. Theory predicts an apparent excess in expected heterozygosity follows a genetic bottleneck. Evidence for such a distortion in genetic diversity was observed after the drop in parasite prevalence under the infinite alleles mutation model but not for the stepwise mutation model. The results are similar to those reported for the human malaria parasite, Plasmodium falciparum, worldwide, and support the conclusion that malaria parasites maintain high genetic diversity in host populations despite the potential for loss in alleles during the transmission cycle or during periods/locations when transmission intensity is low.
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Affiliation(s)
- A M Vardo
- Department of Biology, University of Vermont, Burlington, VT 05405, USA.
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Hoffmann EHE, Malafronte RS, Moraes-Avila SL, Osakabe AL, Wunderlich G, Durham AM, Ribolla PEM, del Portillo HA, Ferreira MU. Origins of sequence diversity in the malaria vaccine candidate merozoite surface protein-2 (MSP-2) in Amazonian isolates of Plasmodium falciparum. Gene 2006; 376:224-30. [PMID: 16716539 DOI: 10.1016/j.gene.2006.03.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Revised: 03/14/2006] [Accepted: 03/15/2006] [Indexed: 11/25/2022]
Abstract
The recent evolution of Plasmodium falciparum is at odds with the extensive polymorphism found in most genes coding for antigens. Here, we examined the patterns and putative mechanisms of sequence diversification in the merozoite surface protein-2 (MSP-2), a major malarial repetitive surface antigen. We compared the msp-2 gene sequences from closely related clones derived from sympatric parasite isolates from Brazilian Amazonia and used microsatellite typing to examine, in these same clones, the haplotype background of chromosome 2, where msp-2 is located. We found examples of msp-2 sequence rearrangements putatively created by nonreciprocal recombinational events, such as replication slippage and gene conversion, while maintaining the chromosome haplotype. We conclude that these nonreciprocal recombination events may represent a major source of antigenic diversity in MSP-2 in P. falciparum populations with low rates of classical meiotic recombination.
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Affiliation(s)
- Erika H E Hoffmann
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374, 05508-900 São Paulo (SP), Brazil
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Hoffmann EHE, Ribolla PEM, Ferreira MU. Genetic relatedness of Plasmodium falciparum isolates and the origin of allelic diversity at the merozoite surface protein-1 (MSP-1) locus in Brazil and Vietnam. Malar J 2003; 2:24. [PMID: 12941155 PMCID: PMC184523 DOI: 10.1186/1475-2875-2-24] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2003] [Accepted: 07/23/2003] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Despite the extensive polymorphism at the merozoite surface protein-1 (MSP-1) locus of Plasmodium falciparum, that encodes a major repetitive malaria vaccine candidate antigen, identical and nearly identical alleles frequently occur in sympatric parasites. Here we used microsatellite haplotyping to estimate the genetic distance between isolates carrying identical and nearly identical MSP-1 alleles. METHODS We analyzed 28 isolates from hypoendemic areas in north-western Brazil, collected between 1985 and 1998, and 23 isolates obtained in mesoendemic southern Vietnam in 1996. MSP-1 alleles were characterized by combining PCR typing with allele-specific primers and partial DNA sequencing. The following single-copy microsatellite markers were typed : Polyalpha, TA42 (only for Brazilian samples), TA81, TA1, TA87, TA109 (only for Brazilian samples), 2490, ARAII, PfG377, PfPK2, and TA60. RESULTS The low pair-wise average genetic distance between microsatellite haplotypes of isolates sharing identical MSP-1 alleles indicates that epidemic propagation of discrete parasite clones originated most identical MSP-1 alleles in parasite populations from Brazil and Vietnam. At least one epidemic clone propagating in Brazil remained relatively unchanged over more than one decade. Moreover, we found no evidence that rearrangements of MSP-1 repeats, putatively created by mitotic recombination events, generated new alleles within clonal lineages of parasites in either country. CONCLUSION Identical MSP-1 alleles originated from co-ancestry in both populations, whereas nearly identical MSP-1 alleles have probably appeared independently in unrelated parasite lineages.
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Affiliation(s)
- Erika HE Hoffmann
- Departamento de Parasitologia, Instituto de Ciências Biomédicas da Universidade de São Paulo, Av. Prof. Lineu Prestes 1374, 05508-900 São Paulo (SP), Brazil
| | - Paulo EM Ribolla
- Departamento de Parasitologia, Instituto de Biociências da Universidade Estadual Paulista, Caixa Postal 510, 18618-000 Botucatu (SP), Brazil
| | - Marcelo U Ferreira
- Departamento de Parasitologia, Instituto de Ciências Biomédicas da Universidade de São Paulo, Av. Prof. Lineu Prestes 1374, 05508-900 São Paulo (SP), Brazil
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