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Ruybal-Pesántez S, Sáenz FE, Deed SL, Johnson EK, Larremore DB, Vera-Arias CA, Tiedje KE, Day KP. Molecular epidemiology of continued Plasmodium falciparum disease transmission after an outbreak in Ecuador. FRONTIERS IN TROPICAL DISEASES 2023. [DOI: 10.3389/fitd.2023.1085862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023] Open
Abstract
To better understand the factors underlying the continued incidence of clinical episodes of falciparum malaria in E-2025 countries targeting elimination, we characterized the molecular epidemiology of Plasmodium falciparum disease transmission after a clonal outbreak in Ecuador. Here we study disease transmission by documenting the diversity and population structure of the major variant surface antigen of the blood stages of P. falciparum encoded by the var multigene family. We used a high-resolution genotyping method, “varcoding”, involving targeted amplicon sequencing to fingerprint the DBLα encoding region of var genes to describe both antigenic var diversity and var repertoire similarity or relatedness in parasite isolates from clinical cases. We identified nine genetic varcodes in 58 P. falciparum isolates causing clinical disease in 2013-2015. Network analyses revealed that four of the varcodes were highly related to the outbreak varcode, with identification of possible diversification of the outbreak parasites by recombination as seen in three of those varcodes. The majority of clinical cases in Ecuador were associated with parasites with highly related or recombinant varcodes to the outbreak clone and due to local transmission rather than recent importation of parasites from other endemic countries. Sharing of types in Ecuadorian varcodes to those sampled in South American varcodes reflects historical parasite importation of some varcodes, especially from Colombia and Peru. Our findings highlight the translational application of varcoding for outbreak surveillance in epidemic/unstable malaria transmission, such as in E-2025 countries, and point to the need for surveillance of local reservoirs of infection in Ecuador to achieve the malaria elimination goal by 2025.
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Guerra AP, Olivera MJ, Cortés LJ, Chenet SM, Macedo de Oliveira A, Lucchi NW. Molecular surveillance for anti-malarial drug resistance and genetic diversity of Plasmodium falciparum after chloroquine and sulfadoxine-pyrimethamine withdrawal in Quibdo, Colombia, 2018. Malar J 2022; 21:306. [PMID: 36307852 PMCID: PMC9617338 DOI: 10.1186/s12936-022-04328-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 08/18/2022] [Indexed: 11/24/2022] Open
Abstract
Background Resistance to anti-malarial drugs is associated with polymorphisms in target genes and surveillance for these molecular markers is important to detect the emergence of mutations associated with drug resistance and signal recovering sensitivity to anti-malarials previously used. Methods The presence of polymorphisms in genes associated with Plasmodium falciparum resistance to chloroquine and sulfadoxine-pyrimethamine was evaluated by Sanger sequencing, in 85 P. falciparum day of enrollment samples from a therapeutic efficacy study of artemether–lumefantrine conducted in 2018–2019 in Quibdo, Colombia. Samples were genotyped to assess mutations in pfcrt (codons 72–76), pfdhfr (codons 51, 59, 108, and 164), and pfdhps genes (codons 436, 437, 540, and 581). Further, the genetic diversity of infections using seven neutral microsatellites (NMSs) (C2M34, C3M69, Poly α, TA1, TA109, 2490, and PfPK2) was assessed. Results All isolates carried mutant alleles for pfcrt (K76T and N75E), and for pfdhfr (N51I and S108N), while for pfdhps, mutations were observed only for codon A437G (32/73, 43.8%). Fifty samples (58.8%) showed a complete neutral microsatellites (NMS) profile. The low mean number of alleles (2 ± 0.57) per locus and mean expected heterozygosity (0.17 ± 0.03) showed a reduced genetic diversity. NMS multilocus genotypes (MMG) were built and nine MMG were identified. Conclusions Overall, these findings confirm the fixation of chloroquine and pyrimethamine-resistant alleles already described in the literature, implying that these drugs are not currently appropriate for use in Colombia. In contrast, mutations in the pfdhps gene were only observed at codon 437, an indication that full resistance to sulfadoxine has not been achieved in Choco. MMGs found matched the clonal lineage E variant 1 previously reported in northwestern Colombia. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04328-x.
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Affiliation(s)
| | | | | | - Stella M Chenet
- Instituto de Investigaciones en Ciencias Biomédicas, Universidad Ricardo Palma, Lima, Perú
| | - Alexandre Macedo de Oliveira
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, GA, Atlanta, USA
| | - Naomi W Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, GA, Atlanta, USA
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Ralinoro F, Rakotomanga TA, Rakotosaona R, Doll Rakoto DA, Menard D, Jeannoda V, Ratsimbasoa A. Genetic diversity of Plasmodium falciparum populations in three malaria transmission settings in Madagascar. Malar J 2021; 20:239. [PMID: 34044837 PMCID: PMC8161981 DOI: 10.1186/s12936-021-03776-1] [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: 01/28/2021] [Accepted: 05/17/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Assessment of the genetic diversity of Plasmodium falciparum parasites from various malaria transmission settings could help to define tailored local strategies for malaria control and elimination. Such assessments are currently scarce in Madagascar. The study presented here aimed to bridge this gap by investigating the genetic diversity of P. falciparum populations in three epidemiological strata (Equatorial, Tropical and Fringes) in Madagascar. METHODS Two-hundred and sixty-six P. falciparum isolates were obtained from patients with uncomplicated malaria enrolled in clinical drug efficacy studies conducted at health centres in Tsaratanana (Equatorial stratum), Antanimbary (Tropical stratum) and Anjoma Ramartina (Fringes) in 2013 and 2016. Parasite DNA was extracted from blood samples collected before anti-malarial treatment. Plasmodium species were identified by nested PCR targeting the 18 S rRNA gene. The genetic profiles of P. falciparum parasites were defined by allele-specific nested PCR on the polymorphic regions of the msp-1 and msp-2 genes. RESULTS Fifty-eight alleles were detected in the P. falciparum samples tested: 18 alleles for msp-1 and 40 for msp-2. K1 (62.9%, 139/221) and FC27 (69.5%, 114/164) were the principal msp-1 and msp-2 allele families detected, although the proportions of the msp-1 and msp-2 alleles varied significantly between sites. Polyclonal infections were more frequent at sites in the Equatorial stratum (69.8%) than at sites in the Tropical stratum (60.5%) or Fringes (58.1%). Population genetics analyses showed that genetic diversity was similar between sites and that parasite flow within sites was limited. CONCLUSIONS This study provides recent information about the genetic diversity of P. falciparum populations in three transmission strata in Madagascar, and valuable baseline data for further evaluation of the impact of the control measures implemented in Madagascar.
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Affiliation(s)
- Fanomezantsoa Ralinoro
- National Malaria Control Programme of Madagascar, Androhibe, Antananarivo, Madagascar. .,Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar.
| | - Tovonahary Angelo Rakotomanga
- National Malaria Control Programme of Madagascar, Androhibe, Antananarivo, Madagascar.,Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar
| | | | | | - Didier Menard
- Malaria Genetics and Resistance Unit and INSERM U1201, Institut Pasteur Paris, Paris, France
| | - Victor Jeannoda
- Faculty of Sciences, University of Antananarivo, Antananarivo, Madagascar
| | - Arsene Ratsimbasoa
- National Malaria Control Programme of Madagascar, Androhibe, Antananarivo, Madagascar. .,Faculty of Medicine, University of Fianarantsoa, Fianarantsoa, Madagascar.
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4
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Kattenberg JH, Razook Z, Keo R, Koepfli C, Jennison C, Lautu-Gumal D, Fola AA, Ome-Kaius M, Barnadas C, Siba P, Felger I, Kazura J, Mueller I, Robinson LJ, Barry AE. Monitoring Plasmodium falciparum and Plasmodium vivax using microsatellite markers indicates limited changes in population structure after substantial transmission decline in Papua New Guinea. Mol Ecol 2020; 29:4525-4541. [PMID: 32985031 PMCID: PMC10008436 DOI: 10.1111/mec.15654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 07/27/2020] [Indexed: 02/01/2023]
Abstract
Monitoring the genetic structure of pathogen populations may be an economical and sensitive approach to quantify the impact of control on transmission dynamics, highlighting the need for a better understanding of changes in population genetic parameters as transmission declines. Here we describe the first population genetic analysis of two major human malaria parasites, Plasmodium falciparum (Pf) and Plasmodium vivax (Pv), following nationwide distribution of long-lasting insecticide-treated nets (LLINs) in Papua New Guinea (PNG). Parasite isolates from pre- (2005-2006) and post-LLIN (2010-2014) were genotyped using microsatellite markers. Despite parasite prevalence declining substantially (East Sepik Province: Pf = 54.9%-8.5%, Pv = 35.7%-5.6%, Madang Province: Pf = 38.0%-9.0%, Pv: 31.8%-19.7%), genetically diverse and intermixing parasite populations remained. Pf diversity declined modestly post-LLIN relative to pre-LLIN (East Sepik: Rs = 7.1-6.4, HE = 0.77-0.71; Madang: Rs = 8.2-6.1, HE = 0.79-0.71). Unexpectedly, population structure present in pre-LLIN populations was lost post-LLIN, suggesting that more frequent human movement between provinces may have contributed to higher gene flow. Pv prevalence initially declined but increased again in one province, yet diversity remained high throughout the study period (East Sepik: Rs = 11.4-9.3, HE = 0.83-0.80; Madang: Rs = 12.2-14.5, HE = 0.85-0.88). Although genetic differentiation values increased between provinces over time, no significant population structure was observed at any time point. For both species, a decline in multiple infections and increasing clonal transmission and significant multilocus linkage disequilibrium post-LLIN were positive indicators of impact on the parasite population using microsatellite markers. These parameters may be useful adjuncts to traditional epidemiological tools in the early stages of transmission reduction.
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Affiliation(s)
- Johanna Helena Kattenberg
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea
| | - Zahra Razook
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
| | - Raksmei Keo
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
| | - Cristian Koepfli
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Charlie Jennison
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Dulcie Lautu-Gumal
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Abebe A Fola
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Maria Ome-Kaius
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Céline Barnadas
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Peter Siba
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - James Kazura
- Centre for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Ivo Mueller
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia.,Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Leanne J Robinson
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Vector Borne Diseases Unit, Papua New Guinea Institute of Medical Research, Yagaum, Papua New Guinea.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia.,Disease Elimination, Burnet Institute, Melbourne, VIC, Australia
| | - Alyssa E Barry
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
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5
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Daniels RF, Chenet S, Rogier E, Lucchi N, Herman C, Pierre B, Lemoine JF, Boncy J, Wirth DF, Chang MA, Udhayakumar V, Volkman SK. Genetic analysis reveals unique characteristics of Plasmodium falciparum parasite populations in Haiti. Malar J 2020; 19:379. [PMID: 33097045 PMCID: PMC7583211 DOI: 10.1186/s12936-020-03439-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/03/2020] [Indexed: 11/18/2022] Open
Abstract
Background With increasing interest in eliminating malaria from the Caribbean region, Haiti is one of the two countries on the island of Hispaniola with continued malaria transmission. While the Haitian population remains at risk for malaria, there are a limited number of cases annually, making conventional epidemiological measures such as case incidence and prevalence of potentially limited value for fine-scale resolution of transmission patterns and trends. In this context, genetic signatures may be useful for the identification and characterization of the Plasmodium falciparum parasite population in order to identify foci of transmission, detect outbreaks, and track parasite movement to potentially inform malaria control and elimination strategies. Methods This study evaluated the genetic signals based on analysis of 21 single-nucleotide polymorphisms (SNPs) from 462 monogenomic (single-genome) P. falciparum DNA samples extracted from dried blood spots collected from malaria-positive patients reporting to health facilities in three southwestern Haitian departments (Nippes, Grand’Anse, and Sud) in 2016. Results Assessment of the parasite genetic relatedness revealed evidence of clonal expansion within Nippes and the exchange of parasite lineages between Nippes, Sud, and Grand'Anse. Furthermore, 437 of the 462 samples shared high levels of genetic similarity–at least 20 of 21 SNPS–with at least one other sample in the dataset. Conclusions These results revealed patterns of relatedness suggestive of the repeated recombination of a limited number of founding parasite types without significant outcrossing. These genetic signals offer clues to the underlying relatedness of parasite populations and may be useful for the identification of the foci of transmission and tracking of parasite movement in Haiti for malaria elimination.
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Affiliation(s)
- Rachel F Daniels
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA.,Broad Institute, Cambridge, MA, USA
| | - Stella Chenet
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA.,Instituto de Medicina Tropical, Universidad Nacional Toribio Rodríguez de Mendoza de Amazonas, Chachapoyas, Peru
| | - Eric Rogier
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Naomi Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Camelia Herman
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA.,CDC Foundation, Atlanta, GA, USA
| | - Baby Pierre
- Ministère de La Santé Publique Et de La Population (MSPP), Programme National de Contrôle de La Malaria, Port-au-Prince, Haiti
| | - Jean Frantz Lemoine
- Ministère de La Santé Publique Et de La Population (MSPP), Programme National de Contrôle de La Malaria, Port-au-Prince, Haiti
| | - Jacques Boncy
- Ministère de La Santé Publique Et de La Population (MSPP), Programme National de Contrôle de La Malaria, Port-au-Prince, Haiti
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA.,Broad Institute, Cambridge, MA, USA
| | - Michelle A Chang
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Sarah K Volkman
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA. .,Broad Institute, Cambridge, MA, USA.
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6
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Abamecha A, El-Abid H, Yilma D, Addisu W, Ibenthal A, Bayih AG, Noedl H, Yewhalaw D, Moumni M, Abdissa A. Genetic diversity and genotype multiplicity of Plasmodium falciparum infection in patients with uncomplicated malaria in Chewaka district, Ethiopia. Malar J 2020; 19:203. [PMID: 32513191 PMCID: PMC7281928 DOI: 10.1186/s12936-020-03278-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/29/2020] [Indexed: 12/03/2022] Open
Abstract
Background Genetic diversity in Plasmodium falciparum poses a major threat to malaria control and elimination interventions. Characterization of the genetic diversity of P. falciparum strains can be used to assess intensity of parasite transmission and identify potential deficiencies in malaria control programmes, which provides vital information to evaluating malaria elimination efforts. This study investigated the P. falciparum genetic diversity and genotype multiplicity of infection in parasite isolates from cases with uncomplicated P. falciparum malaria in Southwest Ethiopia. Methods A total of 80 P. falciparum microscopy and qPCR positive blood samples were collected from study participants aged 6 months to 60 years, who visited the health facilities during study evaluating the efficacy of artemether-lumefantrine from September–December, 2017. Polymorphic regions of the msp-1 and msp-2 were genotyped by nested polymerase chain reactions (nPCR) followed by gel electrophoresis for fragment analysis. Results Of 80 qPCR-positive samples analysed for polymorphisms on msp-1 and msp-2 genes, the efficiency of msp-1 and msp-2 gene amplification reactions with family-specific primers were 95% and 98.8%, respectively. Allelic variation of 90% (72/80) for msp-1 and 86.2% (69/80) for msp-2 were observed. K1 was the predominant msp-1 allelic family detected in 20.8% (15/72) of the samples followed by MAD20 and RO33. Within msp-2, allelic family FC27 showed a higher frequency (26.1%) compared to IC/3D7 (15.9%). Ten different alleles were observed in msp-1 with 6 alleles for K1, 3 alleles for MAD20 and 1 allele for RO33. In msp-2, 19 individual alleles were detected with 10 alleles for FC27 and 9 alleles for 3D7. Eighty percent (80%) of isolates had multiple genotypes and the overall mean multiplicity of infection was 3.2 (95% CI 2.87–3.46). The heterozygosity indices were 0.43 and 0.85 for msp-1 and msp-2, respectively. There was no significant association between multiplicity of infection and age or parasite density. Conclusions The study revealed high levels of genetic diversity and mixed-strain infections of P. falciparum populations in Chewaka district, Ethiopia, suggesting that both endemicity level and malaria transmission remain high and that strengthened control efforts are needed in Ethiopia.
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Affiliation(s)
- Abdulhakim Abamecha
- School of Medical Laboratory Science, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia. .,Department of Biomedical, College of Public Health and Medical Science, Mettu University, Mettu, Ethiopia. .,Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia.
| | - Hassan El-Abid
- Laboratory of Cellular Genomics and Molecular Techniques for Investigation, Faculty of Sciences, Moulay Ismail University, Meknès, Morocco
| | - Daniel Yilma
- Department of Internal Medicine, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Wondimagegn Addisu
- School of Medical Laboratory Science, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Achim Ibenthal
- Faculty of Science and Art, HAWK University, Gottingen, Germany
| | | | - Harald Noedl
- Malaria Research Initiative Bandarban (MARIB), Vienna, Austria
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Science, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Mohieddine Moumni
- Laboratory of Cellular Genomics and Molecular Techniques for Investigation, Faculty of Sciences, Moulay Ismail University, Meknès, Morocco
| | - Alemseged Abdissa
- School of Medical Laboratory Science, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia.,Armauer Hansen Research Institute, Addis Ababa, Ethiopia
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Pacheco MA, Forero-Peña DA, Schneider KA, Chavero M, Gamardo A, Figuera L, Kadakia ER, Grillet ME, Oliveira-Ferreira J, Escalante AA. Malaria in Venezuela: changes in the complexity of infection reflects the increment in transmission intensity. Malar J 2020; 19:176. [PMID: 32380999 PMCID: PMC7206825 DOI: 10.1186/s12936-020-03247-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 04/26/2020] [Indexed: 01/07/2023] Open
Abstract
Background Malaria incidence has reached staggering numbers in Venezuela. Commonly, Bolívar State accounted for approximately 70% of the country cases every year. Most cases cluster in the Sifontes municipality, a region characterized by an extractive economy, including gold mining. An increase in migration to Sifontes, driven by gold mining, fueled a malaria spillover to the rest of the country and the region. Here samples collected in 2018 were compared with a previous study of 2003/2004 to describe changes in the parasites population structures and the frequency of point mutations linked to anti-malarial drugs. Methods A total of 88 Plasmodium falciparum and 94 Plasmodium vivax isolates were collected in 2018 and compared with samples from 2003/2004 (106 P. falciparum and 104 P. vivax). For P. falciparum, mutations linked to drug resistance (Pfdhfr, Pfdhps, and Pfcrt) and the Pfk13 gene associated with artemisinin delayed parasite clearance, were analysed. To estimate the multiplicity of infection (MOI), and perform P. falciparum and P. vivax population genetic analyses, the parasites were genotyped by using eight standardized microsatellite loci. Results The P. falciparum parasites are still harbouring drug-resistant mutations in Pfdhfr, Pfdhps, and Pfcrt. However, there was a decrease in the frequency of highly resistant Pfdhps alleles. Mutations associated with artemisinin delayed parasite clearance in the Pfk13 gene were not found. Consistent with the increase in transmission, polyclonal infections raised from 1.9% in 2003/2004 to 39% in 2018 in P. falciparum and from 16.3 to 68% in P. vivax. There is also a decrease in linkage disequilibrium. Bayesian clustering yields two populations linked to the time of sampling, showing that the parasite populations temporarily changed. However, the samples from 2003/2004 and 2018 have several alleles per locus in common without sharing multi-locus genotypes. Conclusions The frequency of mutations linked with drug resistance in P. falciparum shows only changes in Pfdhps. Observations presented here are consistent with an increase in transmission from the previously circulating parasites. Following populations longitudinally, using molecular surveillance, provides valuable information in cases such as Venezuela with a fluid malaria situation that is affecting the regional goals toward elimination.
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Affiliation(s)
- M Andreína Pacheco
- Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA, USA
| | - David A Forero-Peña
- Escuela de Ciencias de la Salud, Universidad de Oriente, Núcleo Bolívar, Ciudad Bolívar, Venezuela.,Departamento de Medicina Interna, Complejo Hospitalario Universitario "Ruíz y Páez", Ciudad Bolívar, Venezuela.,Biomedical Research and Therapeutic Vaccines Institute, Ciudad Bolívar, Venezuela
| | | | - Melynar Chavero
- Escuela de Ciencias de la Salud, Universidad de Oriente, Núcleo Bolívar, Ciudad Bolívar, Venezuela.,Departamento de Medicina Interna, Complejo Hospitalario Universitario "Ruíz y Páez", Ciudad Bolívar, Venezuela.,Biomedical Research and Therapeutic Vaccines Institute, Ciudad Bolívar, Venezuela
| | - Angel Gamardo
- Biomedical Research and Therapeutic Vaccines Institute, Ciudad Bolívar, Venezuela
| | - Luisamy Figuera
- Departamento de Medicina Interna, Complejo Hospitalario Universitario "Ruíz y Páez", Ciudad Bolívar, Venezuela.,Biomedical Research and Therapeutic Vaccines Institute, Ciudad Bolívar, Venezuela
| | - Esha R Kadakia
- Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA, USA
| | - María E Grillet
- Instituto de Zoología y Ecología Tropical, Universidad Central de Venezuela, Caracas, Venezuela
| | | | - Ananias A Escalante
- Biology Department/Institute of Genomics and Evolutionary Medicine (iGEM), Temple University, Philadelphia, PA, USA.
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8
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Knudson A, González-Casabianca F, Feged-Rivadeneira A, Pedreros MF, Aponte S, Olaya A, Castillo CF, Mancilla E, Piamba-Dorado A, Sanchez-Pedraza R, Salazar-Terreros MJ, Lucchi N, Udhayakumar V, Jacob C, Pance A, Carrasquilla M, Apráez G, Angel JA, Rayner JC, Corredor V. Spatio-temporal dynamics of Plasmodium falciparum transmission within a spatial unit on the Colombian Pacific Coast. Sci Rep 2020; 10:3756. [PMID: 32111872 PMCID: PMC7048816 DOI: 10.1038/s41598-020-60676-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 01/29/2020] [Indexed: 02/07/2023] Open
Abstract
As malaria control programmes concentrate their efforts towards malaria elimination a better understanding of malaria transmission patterns at fine spatial resolution units becomes necessary. Defining spatial units that consider transmission heterogeneity, human movement and migration will help to set up achievable malaria elimination milestones and guide the creation of efficient operational administrative control units. Using a combination of genetic and epidemiological data we defined a malaria transmission unit as the area contributing 95% of malaria cases diagnosed at the catchment facility located in the town of Guapi in the South Pacific Coast of Colombia. We provide data showing that P. falciparum malaria transmission is heterogeneous in time and space and analysed, using topological data analysis, the spatial connectivity, at the micro epidemiological level, between parasite populations circulating within the unit. To illustrate the necessity to evaluate the efficacy of malaria control measures within the transmission unit in order to increase the efficiency of the malaria control effort, we provide information on the size of the asymptomatic reservoir, the nature of parasite genotypes associated with drug resistance as well as the frequency of the Pfhrp2/3 deletion associated with false negatives when using Rapid Diagnostic Tests.
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Affiliation(s)
- Angélica Knudson
- Departamento de Microbiología, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Felipe González-Casabianca
- Departamento de Matemáticas, Facultad de Ciencias, Universidad de Los Andes, Bogotá, Colombia.,Gestión y desarrollo urbanos, Facultad de Ciencia Política, Universidad del Rosario, Bogotá, Colombia
| | | | - Maria Fernanda Pedreros
- Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Samanda Aponte
- Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Adriana Olaya
- Secretaría Departamental de Salud del Cauca, Popayán, Colombia
| | | | - Elvira Mancilla
- Secretaría Departamental de Salud del Cauca, Popayán, Colombia
| | | | - Ricardo Sanchez-Pedraza
- Departamento de Psiquiatria, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Myriam Janeth Salazar-Terreros
- Post-doctoral fellow, Centro de Hematologia e Hemoterapia (HEMOCENTRO), Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
| | - Naomi Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Global Health, Centers for Disease Control and Prevention, Atlanta, 30030, GA, United States of America
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Global Health, Centers for Disease Control and Prevention, Atlanta, 30030, GA, United States of America
| | - Chris Jacob
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, United Kingdom
| | - Alena Pance
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, CB10 1SA, United Kingdom
| | - Manuela Carrasquilla
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, 02115, USA
| | - Giovanni Apráez
- Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia.,Secretaría Departamental de Salud del Cauca, Popayán, Colombia
| | - Jairo Andrés Angel
- Departamento de Matemáticas, Facultad de Ciencias, Universidad de Los Andes, Bogotá, Colombia.,Department of Mathematics and Statistics, Universidad del Norte, Barranquilla, Colombia
| | - Julian C Rayner
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, United Kingdom.
| | - Vladimir Corredor
- Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, Colombia.
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9
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Abstract
Malaria is a vector-borne disease that involves multiple parasite species in a variety of ecological settings. However, the parasite species causing the disease, the prevalence of subclinical infections, the emergence of drug resistance, the scale-up of interventions, and the ecological factors affecting malaria transmission, among others, are aspects that vary across areas where malaria is endemic. Such complexities have propelled the study of parasite genetic diversity patterns in the context of epidemiologic investigations. Importantly, molecular studies indicate that the time and spatial distribution of malaria cases reflect epidemiologic processes that cannot be fully understood without characterizing the evolutionary forces shaping parasite population genetic patterns. Although broad in scope, this review in the Microbiology Spectrum Curated Collection: Advances in Molecular Epidemiology highlights the need for understanding population genetic concepts when interpreting parasite molecular data. First, we discuss malaria complexity in terms of the parasite species involved. Second, we describe how molecular data are changing our understanding of malaria incidence and infectiousness. Third, we compare different approaches to generate parasite genetic information in the context of epidemiologically relevant questions related to malaria control. Finally, we describe a few Plasmodium genomic studies as evidence of how these approaches will provide new insights into the malaria disease dynamics. *This article is part of a curated collection.
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10
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Pringle JC, Wesolowski A, Berube S, Kobayashi T, Gebhardt ME, Mulenga M, Chaponda M, Bobanga T, Juliano JJ, Meshnick S, Moss WJ, Carpi G, Norris DE. High Plasmodium falciparum genetic diversity and temporal stability despite control efforts in high transmission settings along the international border between Zambia and the Democratic Republic of the Congo. Malar J 2019; 18:400. [PMID: 31801548 PMCID: PMC6894251 DOI: 10.1186/s12936-019-3023-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 11/21/2019] [Indexed: 01/25/2023] Open
Abstract
Background While the utility of parasite genotyping for malaria elimination has been extensively documented in low to moderate transmission settings, it has been less well-characterized in holoendemic regions. High malaria burden settings have received renewed attention acknowledging their critical role in malaria elimination. Defining the role for parasite genomics in driving these high burden settings towards elimination will enhance future control programme planning. Methods Amplicon deep sequencing was used to characterize parasite population genetic diversity at polymorphic Plasmodium falciparum loci, Pfama1 and Pfcsp, at two timepoints in June–July 2016 and January–March 2017 in a high transmission region along the international border between Luapula Province, Zambia and Haut-Katanga Province, the Democratic Republic of the Congo (DRC). Results High genetic diversity was observed across both seasons and in both countries. No evidence of population structure was observed between parasite populations on either side of the border, suggesting that this region may be one contiguous transmission zone. Despite a decline in parasite prevalence at the sampling locations in Haut-Katanga Province, no genetic signatures of a population bottleneck were detected, suggesting that larger declines in transmission may be required to reduce parasite genetic diversity. Analysing rare variants may be a suitable alternative approach for detecting epidemiologically important genetic signatures in highly diverse populations; however, the challenge is distinguishing true signals from potential artifacts introduced by small sample sizes. Conclusions Continuing to explore and document the utility of various parasite genotyping approaches for understanding malaria transmission in holoendemic settings will be valuable to future control and elimination programmes, empowering evidence-based selection of tools and methods to address pertinent questions, thus enabling more efficient resource allocation.
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Affiliation(s)
- Julia C Pringle
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
| | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Sophie Berube
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Mary E Gebhardt
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | | | | | - Thierry Bobanga
- Université Protestante au Congo and University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Jonathan J Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Steven Meshnick
- Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Giovanna Carpi
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Douglas E Norris
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
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11
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Vera-Arias CA, Castro LE, Gómez-Obando J, Sáenz FE. Diverse origin of Plasmodium falciparum in northwest Ecuador. Malar J 2019; 18:251. [PMID: 31349843 PMCID: PMC6660669 DOI: 10.1186/s12936-019-2891-y] [Citation(s) in RCA: 10] [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] [Received: 02/04/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Ecuador plans to eliminate malaria by 2020, and the country has already seen a decrease in the number of cases from more than 100,000 in 2000 to only 618 in 2015. Around 30% of malaria infections in Ecuador are caused by Plasmodium falciparum. Most malaria population genetics studies performed in Latin America, especially in the Pacific Coast, indicate a high clonality and a clear structure of P. falciparum populations. It was shown that an outbreak of P. falciparum in northwest Ecuador was the result of a clonal expansion of parasites circulating at low levels in the country or re-invading Ecuador from neighbouring territories. However, general characteristics of P. falciparum circulating in the northwest coast of Ecuador have not been determined. The main goal of this study was to genetically characterize the population structure of P. falciparum in coastal Ecuadorian localities bordering with Colombia. METHODS Molecular investigation of 41 samples collected from 2013 to 2016 in San Lorenzo County, northwest Ecuador was performed using seven neutral microsatellite markers. RESULTS The genetic population structure of P. falciparum in northwest Ecuador is clearly defined as three different genetic groups previously reported in Ecuador, Peru and Colombia. CONCLUSIONS The limited number of P. falciparum clonal types that are circulating in northwest Ecuador, are related to ancestral parasite clonal lineages reported in the Pacific Coast. These parasites could be a product of migration from neighbouring regions or residual clonal types circulating in the country in low proportions. Studies of the genetic characterization of P. falciparum in eliminating areas help determine the possible origin of parasites in order to create strategies to prevent the entrance of new lineages and achieve local elimination of malaria.
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Affiliation(s)
- Claudia A Vera-Arias
- Centro de Investigación para la Salud en América Latina, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Av. 12 de octubre 1076, Apartado: 17-01-2184, Quito, Ecuador
| | | | - Javier Gómez-Obando
- Ministerio de Salud Pública, Distrito de Salud de San Lorenzo, San Lorenzo, Ecuador
| | - Fabián E Sáenz
- Centro de Investigación para la Salud en América Latina, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Av. 12 de octubre 1076, Apartado: 17-01-2184, Quito, Ecuador.
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12
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Redmond SN, MacInnis BM, Bopp S, Bei AK, Ndiaye D, Hartl DL, Wirth DF, Volkman SK, Neafsey DE. De Novo Mutations Resolve Disease Transmission Pathways in Clonal Malaria. Mol Biol Evol 2019; 35:1678-1689. [PMID: 29722884 PMCID: PMC5995194 DOI: 10.1093/molbev/msy059] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Detecting de novo mutations in viral and bacterial pathogens enables researchers to reconstruct detailed networks of disease transmission and is a key technique in genomic epidemiology. However, these techniques have not yet been applied to the malaria parasite, Plasmodium falciparum, in which a larger genome, slower generation times, and a complex life cycle make them difficult to implement. Here, we demonstrate the viability of de novo mutation studies in P. falciparum for the first time. Using a combination of sequencing, library preparation, and genotyping methods that have been optimized for accuracy in low-complexity genomic regions, we have detected de novo mutations that distinguish nominally identical parasites from clonal lineages. Despite its slower evolutionary rate compared with bacterial or viral species, de novo mutation can be detected in P. falciparum across timescales of just 1–2 years and evolutionary rates in low-complexity regions of the genome can be up to twice that detected in the rest of the genome. The increased mutation rate allows the identification of separate clade expansions that cannot be found using previous genomic epidemiology approaches and could be a crucial tool for mapping residual transmission patterns in disease elimination campaigns and reintroduction scenarios.
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Affiliation(s)
- Seth N Redmond
- Broad Institute of MIT and Harvard, Cambridge, MA.,Harvard T.H. Chan School of Public Health, Boston, MA
| | - Bronwyn M MacInnis
- Broad Institute of MIT and Harvard, Cambridge, MA.,Harvard T.H. Chan School of Public Health, Boston, MA
| | - Selina Bopp
- Broad Institute of MIT and Harvard, Cambridge, MA.,Harvard T.H. Chan School of Public Health, Boston, MA
| | - Amy K Bei
- Harvard T.H. Chan School of Public Health, Boston, MA.,Department of Parasitology, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Daouda Ndiaye
- Harvard T.H. Chan School of Public Health, Boston, MA.,Department of Parasitology, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Daniel L Hartl
- Broad Institute of MIT and Harvard, Cambridge, MA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA
| | - Dyann F Wirth
- Broad Institute of MIT and Harvard, Cambridge, MA.,Harvard T.H. Chan School of Public Health, Boston, MA
| | - Sarah K Volkman
- Broad Institute of MIT and Harvard, Cambridge, MA.,Harvard T.H. Chan School of Public Health, Boston, MA.,Department of Nursing, School of Nursing and Health Sciences, Simmons College, Boston, MA, 02115
| | - Daniel E Neafsey
- Broad Institute of MIT and Harvard, Cambridge, MA.,Harvard T.H. Chan School of Public Health, Boston, MA
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13
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Patel P, Bharti PK, Bansal D, Raman RK, Mohapatra PK, Sehgal R, Mahanta J, Sultan AA, Singh N. Genetic diversity and antibody responses against Plasmodium falciparum vaccine candidate genes from Chhattisgarh, Central India: Implication for vaccine development. PLoS One 2017; 12:e0182674. [PMID: 28787005 PMCID: PMC5546615 DOI: 10.1371/journal.pone.0182674] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 07/21/2017] [Indexed: 11/22/2022] Open
Abstract
The genetic diversity in Plasmodium falciparum antigens is a major hurdle in developing an effective malaria vaccine. Protective efficacy of the vaccine is dependent on the polymorphic alleles of the vaccine candidate antigens. Therefore, we investigated the genetic diversity of the potential vaccine candidate antigens i.e. msp-1, msp-2, glurp, csp and pfs25 from field isolates of P.falciparum and determined the natural immune response against the synthetic peptide of these antigens. Genotyping was performed using Sanger method and size of alleles, multiplicity of infection, heterogeneity and recombination rate were analyzed. Asexual stage antigens were highly polymorphic with 55 and 50 unique alleles in msp-1 and msp-2 genes, respectively. The MOI for msp-1 and msp-2 were 1.67 and 1.28 respectively. A total 59 genotype was found in glurp gene with 8 types of amino acid repeats in the conserved part of RII repeat region. The number of NANP repeats from 40 to 44 was found among 55% samples in csp gene while pfs25 was found almost conserved with only two amino acid substitution site. The level of genetic diversity in the present study population was very similar to that from Asian countries. A higher IgG response was found in the B-cell epitopes of msp-1 and csp antigens and higher level of antibodies against csp B-cell epitope and glurp antigen were recorded with increasing age groups. Significantly, higher positive responses were observed in the csp antigen among the samples with ≥42 NANP repeats. The present finding showed extensive diversity in the asexual stage antigens.
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Affiliation(s)
- Priyanka Patel
- National Institute for Research in Tribal Health, Indian Council of Medical Research, Garha, Jabalpur, Madhya Pradesh, India
| | - Praveen K. Bharti
- National Institute for Research in Tribal Health, Indian Council of Medical Research, Garha, Jabalpur, Madhya Pradesh, India
| | - Devendra Bansal
- Department of Microbiology and Immunology, Weill Cornell Medicine - Qatar, Cornell University, Qatar Foundation - Education City, Doha, Qatar
| | - Rajive K. Raman
- Community Health Centre Janakpur, District Baikunthpur, Chhattisgarh, India
| | - Pradyumna K. Mohapatra
- Regional Medical Research Centre, NE, Indian Council of Medical Research, Dibrugarh, Assam, India
| | - Rakesh Sehgal
- Department of Parasitology, Postgraduate Institute of Medical Education and Research, Chandigarh, Punjab, India
| | - Jagadish Mahanta
- Regional Medical Research Centre, NE, Indian Council of Medical Research, Dibrugarh, Assam, India
| | - Ali A. Sultan
- Department of Microbiology and Immunology, Weill Cornell Medicine - Qatar, Cornell University, Qatar Foundation - Education City, Doha, Qatar
| | - Neeru Singh
- National Institute for Research in Tribal Health, Indian Council of Medical Research, Garha, Jabalpur, Madhya Pradesh, India
- * E-mail:
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14
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Characterizing the malaria rural-to-urban transmission interface: The importance of reactive case detection. PLoS Negl Trop Dis 2017; 11:e0005780. [PMID: 28715415 PMCID: PMC5531679 DOI: 10.1371/journal.pntd.0005780] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/27/2017] [Accepted: 07/05/2017] [Indexed: 11/19/2022] Open
Abstract
Background Reported urban malaria cases are increasing in Latin America, however, evidence of such trend remains insufficient. Here, we propose an integrated approach that allows characterizing malaria transmission at the rural-to-urban interface by combining epidemiological, entomological, and parasite genotyping methods. Methods/Principal findings A descriptive study that combines active (ACD), passive (PCD), and reactive (RCD) case detection was performed in urban and peri-urban neighborhoods of Quibdó, Colombia. Heads of households were interviewed and epidemiological surveys were conducted to assess malaria prevalence and identify potential risk factors. Sixteen primary cases, eight by ACD and eight by PCD were recruited for RCD. Using the RCD strategy, prevalence of 1% by microscopy (6/604) and 9% by quantitative polymerase chain reaction (qPCR) (52/604) were found. A total of 73 houses and 289 volunteers were screened leading to 41 secondary cases, all of them in peri-urban settings (14% prevalence). Most secondary cases were genetically distinct from primary cases indicating that there were independent occurrences. Plasmodium vivax was the predominant species (76.3%, 71/93), most of them being asymptomatic (46/71). Urban and peri-urban neighborhoods had significant sociodemographic differences. Twenty-four potential breeding sites were identified, all in peri-urban areas. The predominant vectors for 1,305 adults were Anopheles nuneztovari (56,2%) and An. Darlingi (42,5%). One An. nuneztovari specimen was confirmed naturally infected with P. falciparum by ELISA. Conclusions This study found no evidence supporting the existence of urban malaria transmission in Quibdó. RCD strategy was more efficient for identifying malaria cases than ACD alone in areas where malaria transmission is variable and unstable. Incorporating parasite genotyping allows discovering hidden patterns of malaria transmission that cannot be detected otherwise. We propose to use the term “focal case” for those primary cases that lead to discovery of secondary but genetically unrelated malaria cases indicating undetected malaria transmission. Malaria is a disease of rural areas in developing countries. Although a rise in urban malaria cases has been noted during the last decade, this trend could be an artifact due to lack of solid data. In order to better understand “urban” and “peri-urban” malaria, we developed a rigorous and systematic methodology that allows characterizing malaria risk in such settings. Our approach is based on cross-sectional studies using active and reactive case detection strategies, genotyping of parasite isolates in order to better understand transmission patterns, and the local assessment of the entomological factors that allow active transmission in urban and peri-urban neighborhoods. This approach was tested in Quibdó, Colombia. No evidence of malaria transmission in urban areas was found. However, we found solid evidence indicating transmission in peri-urban areas due to Plasmodium vivax (86%). This was supported by the identification of Anopheles mosquitoes and their breeding places. Our results show that reactive case detection is not only an effective strategy to identify cases in areas where transmission is variable and unstable, but also allows the detection of hidden transmission when combined with genotyping methods. Such patterns are undetected by traditional surveillance methods.
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15
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Auburn S, Barry AE. Dissecting malaria biology and epidemiology using population genetics and genomics. Int J Parasitol 2016; 47:77-85. [PMID: 27825828 DOI: 10.1016/j.ijpara.2016.08.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/09/2016] [Accepted: 08/25/2016] [Indexed: 10/20/2022]
Abstract
Molecular approaches have an increasingly recognized utility in surveillance of malaria parasite populations, not only in defining prevalence and incidence with higher sensitivity than traditional methods, but also in monitoring local and regional parasite transmission patterns. In this review, we provide an overview of population genetic and genomic studies of human-infecting Plasmodium species, highlighting recent advances in the field. In accordance with the renewed impetus for malaria eradication, many studies are now using genetic and genomic epidemiology to support local evidence-based intervention strategies. Microsatellite genotyping remains a popular approach for both Plasmodium falciparum and Plasmodium vivax. However, with the increasing availability of whole genome sequencing data enabling effective single nucleotide polymorphism-based panels tailored to a given study question and setting, this approach is gaining popularity. The availability of new reference genomes for Plasmodium malariae and Plasmodium ovale should see a surge in similar molecular studies on these currently neglected species. Genomic studies are revealing new insights into important adaptive mechanisms of the parasite including antimalarial drug resistance. The advent of new methodologies such as selective whole genome amplification for dealing with extensive human DNA in low density field isolates should see genome-wide approaches becoming routine for parasite surveillance once the economic costs outweigh the current cost benefits of targeted approaches.
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Affiliation(s)
- Sarah Auburn
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Australia
| | - Alyssa E Barry
- Division of Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia; Department of Medical Biology, University of Melbourne, Melbourne, Australia.
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16
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Mohd Abd Razak MR, Sastu UR, Norahmad NA, Abdul-Karim A, Muhammad A, Muniandy PK, Jelip J, Rundi C, Imwong M, Mudin RN, Abdullah NR. Genetic Diversity of Plasmodium falciparum Populations in Malaria Declining Areas of Sabah, East Malaysia. PLoS One 2016; 11:e0152415. [PMID: 27023787 PMCID: PMC4811561 DOI: 10.1371/journal.pone.0152415] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/14/2016] [Indexed: 11/19/2022] Open
Abstract
Malaysia has a national goal to eliminate malaria by 2020. Understanding the genetic diversity of malaria parasites in residual transmission foci can provide invaluable information which may inform the intervention strategies used to reach elimination targets. This study was conducted to determine the genetic diversity level of P. falciparum isolates in malaria residual foci areas of Sabah. Malaria active case detection was conducted in Kalabakan and Kota Marudu. All individuals in the study sites were screened for malaria infection by rapid diagnostic test. Blood from P. falciparum-infected individuals were collected on filter paper prior to DNA extraction. Genotyping was performed using merozoite surface protein-1 (MSP-1), merozoite surface protein-2 (MSP-2), glutamate rich protein (GLURP) and 10 neutral microsatellite loci markers. The size of alleles, multiplicity of infection (MOI), mean number of alleles (Na), expected heterozygosity (He), linkage disequilibrium (LD) and genetic differentiation (FST) were determined. In Kalabakan, the MSP-1 and MSP-2 alleles were predominantly K1 and FC27 family types, respectively. The GLURP genotype VI (751-800 bp) was predominant. The MOI for MSP-1 and MSP-2 were 1.65 and 1.20, respectively. The Na per microsatellite locus was 1.70. The He values for MSP-1, MSP-2, GLURP and neutral microsatellites were 0.17, 0.37, 0.70 and 0.33, respectively. In Kota Marudu, the MSP-1 and MSP-2 alleles were predominantly MAD20 and 3D7 family types, respectively. The GLURP genotype IV (651-700 bp) was predominant. The MOI for both MSP-1 and MSP-2 was 1.05. The Na per microsatellite locus was 3.60. The He values for MSP-1, MSP-2, GLURP and neutral microsatellites were 0.24, 0.25, 0.69 and 0.30, respectively. A significant LD was observed in Kalabakan (0.495, p<0.01) and Kota Marudu P. falciparum populations (0.601, p<0.01). High genetic differentiation between Kalabakan and Kota Marudu P. falciparum populations was observed (FST = 0.532). The genetic data from the present study highlighted the limited diversity and contrasting genetic pattern of P. falciparum populations in the malaria declining areas of Sabah.
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Affiliation(s)
| | - Umi Rubiah Sastu
- Herbal Medicine Research Center, Institute for Medical Research, Kuala Lumpur, Malaysia
| | - Nor Azrina Norahmad
- Herbal Medicine Research Center, Institute for Medical Research, Kuala Lumpur, Malaysia
| | - Abass Abdul-Karim
- Zonal Public Health Laboratory, Tamale Teaching Hospital, Tamale, Northern Region, Ghana, West Africa
| | - Amirrudin Muhammad
- Herbal Medicine Research Center, Institute for Medical Research, Kuala Lumpur, Malaysia
| | - Prem Kumar Muniandy
- Herbal Medicine Research Center, Institute for Medical Research, Kuala Lumpur, Malaysia
| | - Jenarun Jelip
- Sabah State Health Department, Rumah Persekutuan, Kota Kinabalu, Sabah, Malaysia
| | - Christina Rundi
- Sabah State Health Department, Rumah Persekutuan, Kota Kinabalu, Sabah, Malaysia
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rose Nani Mudin
- Vector Borne Disease Sector, Disease Control Division, Ministry of Health, Federal Government Administrative Centre, Putrajaya, Malaysia
| | - Noor Rain Abdullah
- Herbal Medicine Research Center, Institute for Medical Research, Kuala Lumpur, Malaysia
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