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Fola AA, Kobayashi T, Shields T, Hamapumbu H, Musonda M, Katowa B, Matoba J, Stevenson JC, Norris DE, Thuma PE, Wesolowski A, Moss WJ, Juliano JJ, Bailey JA. Temporal genomic analysis of Plasmodium falciparum reveals increased prevalence of mutations associated with delayed clearance following treatment with artemisinin-lumefantrine in Choma District, Southern Province, Zambia. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.06.05.24308497. [PMID: 38883763 PMCID: PMC11178023 DOI: 10.1101/2024.06.05.24308497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
The emergence of antimalarial drug resistance is an impediment to malaria control and elimination in Africa. Analysis of temporal trends in molecular markers of resistance is critical to inform policy makers and guide malaria treatment guidelines. In a low and seasonal transmission region of southern Zambia, we successfully genotyped 85.5% (389/455) of Plasmodium falciparum samples collected between 2013-2018 from 8 spatially clustered health centres using molecular inversion probes (MIPs) targeting key drug resistance genes. Aside from one sample carrying K13 R622I, none of the isolates carried other World Health Organization-validated or candidate artemisinin partial resistance (ART-R) mutations in K13. However, 13% (CI, 9.6-17.2) of isolates had the AP2MU S160N mutation, which has been associated with delayed clearance following artemisinin combination therapy in Africa. This mutation increased in prevalence between 2015-2018 and bears a genomic signature of selection. During this time period, there was an increase in the MDR1 NFD haplotype that is associated with reduced susceptibility to lumefantrine. Sulfadoxine-pyrimethamine polymorphisms were near fixation. While validated ART-R mutations are rare, a mutation associated with slow parasite clearance in Africa appears to be under selection in southern Zambia.
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Affiliation(s)
- Abebe A. Fola
- Department of Pathology and Laboratory Medicine, Brown University, RI, USA, 02906
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 21205
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 21205
| | | | | | - Ben Katowa
- Macha Research Trust, Choma District, Zambia
| | | | | | - Douglas E. Norris
- Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 21205
| | | | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 21205
| | - William J. Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 21205
- Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 21205
| | - Jonathan J. Juliano
- Institute for Global Health and Infectious Diseases, University of North Carolina Chapel Hill, NC, USA, 27599
- Division of Infectious Diseases, School of Medicine, University of North Carolina Chapel Hill, Chapel Hill, NC 27599
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina Chapel Hill, Chapel Hill, NC, USA, 27599
- Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina Chapel Hill, Chapel Hill, NC 27599
| | - Jeffrey A. Bailey
- Department of Pathology and Laboratory Medicine, Brown University, RI, USA, 02906
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He Q, Chaillet JK, Labbé F. Antigenic strain diversity predicts different biogeographic patterns of maintenance and decline of antimalarial drug resistance. eLife 2024; 12:RP90888. [PMID: 38363295 PMCID: PMC10942604 DOI: 10.7554/elife.90888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024] Open
Abstract
The establishment and spread of antimalarial drug resistance vary drastically across different biogeographic regions. Though most infections occur in sub-Saharan Africa, resistant strains often emerge in low-transmission regions. Existing models on resistance evolution lack consensus on the relationship between transmission intensity and drug resistance, possibly due to overlooking the feedback between antigenic diversity, host immunity, and selection for resistance. To address this, we developed a novel compartmental model that tracks sensitive and resistant parasite strains, as well as the host dynamics of generalized and antigen-specific immunity. Our results show a negative correlation between parasite prevalence and resistance frequency, regardless of resistance cost or efficacy. Validation using chloroquine-resistant marker data supports this trend. Post discontinuation of drugs, resistance remains high in low-diversity, low-transmission regions, while it steadily decreases in high-diversity, high-transmission regions. Our study underscores the critical role of malaria strain diversity in the biogeographic patterns of resistance evolution.
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Affiliation(s)
- Qixin He
- Department of Biological Sciences, Purdue UniversityWest LafayetteUnited States
| | - John K Chaillet
- Department of Biological Sciences, Purdue UniversityWest LafayetteUnited States
| | - Frédéric Labbé
- Department of Ecology and Evolution, University of ChicagoChicagoUnited States
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He Q, Chaillet JK, Labbé F. Antigenic strain diversity predicts different biogeographic patterns of maintenance and decline of anti-malarial drug resistance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531320. [PMID: 37987011 PMCID: PMC10659383 DOI: 10.1101/2023.03.06.531320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The establishment and spread of anti-malarial drug resistance vary drastically across different biogeographic regions. Though most infections occur in Sub-Saharan Africa, resistant strains often emerge in low-transmission regions. Existing models on resistance evolution lack consensus on the relationship between transmission intensity and drug resistance, possibly due to overlooking the feedback between antigenic diversity, host immunity, and selection for resistance. To address this, we developed a novel compartmental model that tracks sensitive and resistant parasite strains, as well as the host dynamics of generalized and antigen-specific immunity. Our results show a negative correlation between parasite prevalence and resistance frequency, regardless of resistance cost or efficacy. Validation using chloroquine-resistant marker data supports this trend. Post discontinuation of drugs, resistance remains high in low-diversity, low-transmission regions, while it steadily decreases in high-diversity, high-transmission regions. Our study underscores the critical role of malaria strain diversity in the biogeographic patterns of resistance evolution.
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Affiliation(s)
- Qixin He
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - John K. Chaillet
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Frédéric Labbé
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
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Paschalidis A, Watson OJ, Aydemir O, Verity R, Bailey JA. coiaf: Directly estimating complexity of infection with allele frequencies. PLoS Comput Biol 2023; 19:e1010247. [PMID: 37294835 PMCID: PMC10310041 DOI: 10.1371/journal.pcbi.1010247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/29/2023] [Accepted: 05/01/2023] [Indexed: 06/11/2023] Open
Abstract
In malaria, individuals are often infected with different parasite strains. The complexity of infection (COI) is defined as the number of genetically distinct parasite strains in an individual. Changes in the mean COI in a population have been shown to be informative of changes in transmission intensity with a number of probabilistic likelihood and Bayesian models now developed to estimate the COI. However, rapid, direct measures based on heterozygosity or FwS do not properly represent the COI. In this work, we present two new methods that use easily calculated measures to directly estimate the COI from allele frequency data. Using a simulation framework, we show that our methods are computationally efficient and comparably accurate to current approaches in the literature. Through a sensitivity analysis, we characterize how the distribution of parasite densities, the assumed sequencing depth, and the number of sampled loci impact the bias and accuracy of our two methods. Using our developed methods, we further estimate the COI globally from Plasmodium falciparum sequencing data and compare the results against the literature. We show significant differences in the estimated COI globally between continents and a weak relationship between malaria prevalence and COI.
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Affiliation(s)
- Aris Paschalidis
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island, United States of America
| | - Oliver J. Watson
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island, United States of America
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Ozkan Aydemir
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island, United States of America
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Robert Verity
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Jeffrey A. Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island, United States of America
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Tadele G, Jaiteh FK, Oboh M, Oriero E, Dugassa S, Amambua-Ngwa A, Golassa L. Low genetic diversity of Plasmodium falciparum merozoite surface protein 1 and 2 and multiplicity of infections in western Ethiopia following effective malaria interventions. Malar J 2022; 21:383. [PMID: 36522733 PMCID: PMC9753253 DOI: 10.1186/s12936-022-04394-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 11/19/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Genetic diversity of malaria parasites can inform the intensity of transmission and poses a major threat to malaria control and elimination interventions. Characterization of the genetic diversity would provide essential information about the ongoing control efforts. This study aimed to explore allelic polymorphism of merozoite surface protein 1 (msp1) and merozoite surface protein 2 (msp2) to determine the genetic diversity and multiplicity of Plasmodium falciparum infections circulating in high and low transmission sites in western Ethiopia. METHODS Parasite genomic DNA was extracted from a total of 225 dried blood spots collected from confirmed uncomplicated P. falciparum malaria-infected patients in western Ethiopia. Of these, 72.4% (163/225) and 27.6% (62/225) of the samples were collected in high and low transmission areas, respectively. Polymorphic msp1 and msp2 genes were used to explore the genetic diversity and multiplicity of falciparum malaria infections. Genotyping of msp1 was successful in 86.5% (141/163) and 88.7% (55/62) samples collected from high and low transmission areas, respectively. Genotyping of msp2 was carried out among 85.3% (139/163) and 96.8% (60/62) of the samples collected in high and low transmission sites, respectively. Plasmodium falciparum msp1 and msp2 genes were amplified by nested PCR and the PCR products were analysed by QIAxcel ScreenGel Software. A P-value of less or equal to 0.05 was considered significant. RESULTS High prevalence of falciparum malaria was identified in children less than 15 years as compared with those ≥ 15 years old (AOR = 2.438, P = 0.005). The three allelic families of msp1 (K1, MAD20, and RO33) and the two allelic families of msp2 (FC27 and 3D7), were observed in samples collected in high and low transmission areas. However, MAD 20 and FC 27 alleles were the predominant allelic families in both settings. Plasmodium falciparum isolates circulating in western Ethiopia had low genetic diversity and mean MOI. No difference in mean MOI between high transmission sites (mean MOI 1.104) compared with low transmission area (mean MOI 1.08) (p > 0.05). The expected heterozygosity of msp1 was slightly higher in isolates collected from high transmission sites (He = 0.17) than in those isolates from low transmission (He = 0.12). However, the heterozygosity of msp2 was not different in both settings (Pfmsp2: 0.04 in high transmission; pfmsp2: 0.03 in low transmission). CONCLUSION Plasmodium falciparum from clinical malaria cases in western Ethiopia has low genetic diversity and multiplicity of infection irrespective of the intensity of transmission at the site of sampling. These may be signaling the effectiveness of malaria control strategies in Ethiopia; although further studies are required to determine how specific intervention strategies and other parameters that drive the pattern.
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Affiliation(s)
- Geletta Tadele
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Fatou K Jaiteh
- Medical Research Council Unit the Gambia, London School of Hygiene and Tropical Medicine, Serrekunda, The Gambia
| | - Mary Oboh
- Medical Research Council Unit the Gambia, London School of Hygiene and Tropical Medicine, Serrekunda, The Gambia
| | - Eniyou Oriero
- Medical Research Council Unit the Gambia, London School of Hygiene and Tropical Medicine, Serrekunda, The Gambia
| | - Sisay Dugassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit the Gambia, London School of Hygiene and Tropical Medicine, Serrekunda, The Gambia
| | - Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
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Kamiya T, Paton DG, Catteruccia F, Reece SE. Targeting malaria parasites inside mosquitoes: ecoevolutionary consequences. Trends Parasitol 2022; 38:1031-1040. [PMID: 36209032 PMCID: PMC9815470 DOI: 10.1016/j.pt.2022.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 09/13/2022] [Accepted: 09/13/2022] [Indexed: 11/05/2022]
Abstract
Proof-of-concept studies demonstrate that antimalarial drugs designed for human treatment can also be applied to mosquitoes to interrupt malaria transmission. Deploying a new control tool is ideally undertaken within a stewardship programme that maximises a drug's lifespan by minimising the risk of resistance evolution and slowing its spread once emerged. We ask: what are the epidemiological and evolutionary consequences of targeting parasites within mosquitoes? Our synthesis argues that targeting parasites inside mosquitoes (i) can be modelled by readily expanding existing epidemiological frameworks; (ii) provides a functionally novel control method that has potential to be more robust to resistance evolution than targeting parasites in humans; and (iii) could extend the lifespan and clinical benefit of antimalarials used exclusively to treat humans.
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Affiliation(s)
- Tsukushi Kamiya
- Centre for Interdisciplinary Research in Biology, Collège de France, Paris, France; HRB Clinical Research Facility, National University of Ireland, Galway, Ireland; Institute of Ecology and Evolution, and Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
| | - Douglas G Paton
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Flaminia Catteruccia
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA; Howard Hughes Medical Institute, Boston, MA, USA
| | - Sarah E Reece
- Institute of Ecology and Evolution, and Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
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Antiplasmodial, Antitrypanosomal, and Cytotoxic Effects of Anthonotha macrophylla, Annickia polycarpa, Tieghemella heckelii, and Antrocaryon micraster Extracts. Adv Pharmacol Pharm Sci 2022; 2022:9195753. [PMID: 35915745 PMCID: PMC9338877 DOI: 10.1155/2022/9195753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 11/18/2022] Open
Abstract
Malaria and trypanosomiasis are protozoan diseases which pose a devastating challenge to human health and productivity especially, in Africa where their respective vectors (female Anopheles mosquito and tsetse fly) abound. Various medicinal plants are used to treat these parasitic diseases. However, the scientific basis of their use and toxicological profiles have not been assessed. We have, therefore, evaluated the antiplasmodial, antitrypanosomal, and cytotoxic activities of four African medicinal plant extracts namely, Anthonotha macrophylla leaf (AML), Annickia polycarpa leaf (APLE), Tieghemella heckelii stem bark (THBE), and Antrocaryon micraster stem bark (AMSBE) extracts in vitro against P. falciparum (W2mef laboratory strain), T. brucei (GUTat 3.1 strain), and mammalian RAW 264.7 macrophage cell line, respectively. The most active antiplasmodial extract was AML (IC50 = 5.0 ± 0.08 μg/mL with SI of 21.9). THBE also, produced the most effective antitrypanosomal activity (IC50 = 11.0 ± 0.09 μg/mL and SI of 10.2) among the extracts. In addition, none of the extracts produced toxic effect in the RAW 264.7 macrophage cell line except APLE which was moderately cytotoxic and also produced the least SI in both antitrypanosomal and antiplasmodial assays. These results suggest that AML and THBE could offer safe and alternative therapy for malaria and trypanosomiasis. This is the first study to report the antitrypanosomal and in vitro antiplasmodial activities of these four plants/plant parts. The cytotoxicity of the plant parts used is also being reported for the first time except for the T. heckelii stem bark.
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Genetic Diversity of Plasmodium falciparum and Distribution of Antimalarial Drug Resistance Mutations in Symptomatic and Asymptomatic Infections. Antimicrob Agents Chemother 2022; 66:e0018822. [DOI: 10.1128/aac.00188-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Malaria control relies on passive case detection, and this strategy fails detecting asymptomatic infections. In addition, infections in endemic areas harbor multiple parasite genotypes that could affect case management and malaria epidemiology.
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Ataba E, Dorkenoo AM, Nguepou CT, Bakai T, Tchadjobo T, Kadzahlo KD, Yakpa K, Atcha-Oubou T. Potential Emergence of Plasmodium Resistance to Artemisinin Induced by the Use of Artemisia annua for Malaria and COVID-19 Prevention in Sub-African Region. Acta Parasitol 2022; 67:55-60. [PMID: 34797496 PMCID: PMC8602884 DOI: 10.1007/s11686-021-00489-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/26/2021] [Indexed: 12/23/2022]
Abstract
Plasmodium resistance to antimalarial drugs is an obstacle to the elimination of malaria in endemic areas. This situation is particularly dramatic for Africa, which accounts for nearly 92% of malaria cases worldwide. Drug pressure has been identified as a key factor in the emergence of antimalarial drug resistance. Indeed, this pressure is favoured by several factors, including the use of counterfeit forms of antimalarials, inadequate prescription controls, poor adherence to treatment regimens, dosing errors, and the increasing use of other forms of unapproved antimalarials. This resistance has led to the replacement of chloroquine (CQ) by artemisinin-based combination therapies (ACTs) which are likely to become ineffective in the coming years due to the uncontrolled use of Artemisia annua in the sub-Saharan African region for malaria prevention and COVID-19. The use of Artemisia annua for the prevention of malaria and COVID-19 could be an important factor in the emergence of resistance to Artemisinin-based combination therapies.
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Affiliation(s)
- Essoham Ataba
- Ecole Supérieure des Techniques Biologiques et Alimentaires (ESTBA) /Unité de Recherche en Immunologie et Immunomodulation (UR2IM), Université de Lomé, Boulevard Eyadema, 01BP 1515 Lomé, Togo
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Ameyo M. Dorkenoo
- Faculté des Sciences de la Santé, Université de Lomé, Boulevard Eyadema, 01BP 1515 Lomé, Togo
| | - Christèle Tchopba Nguepou
- Ecole Supérieure des Techniques Biologiques et Alimentaires (ESTBA) /Unité de Recherche en Immunologie et Immunomodulation (UR2IM), Université de Lomé, Boulevard Eyadema, 01BP 1515 Lomé, Togo
| | - Tchaa Bakai
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Tchassama Tchadjobo
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Komla Dovenè Kadzahlo
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Kossi Yakpa
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
| | - Tinah Atcha-Oubou
- Programme National de Lutte Contre le Paludisme, Ministère de la Santé de l’Hygiène Publique et de l’Accès Universel Aux Soins, Quartier Administratif, 01BP 518 Lomé, Togo
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Whitlock AOB, Juliano JJ, Mideo N. Immune selection suppresses the emergence of drug resistance in malaria parasites but facilitates its spread. PLoS Comput Biol 2021; 17:e1008577. [PMID: 34280179 PMCID: PMC8321109 DOI: 10.1371/journal.pcbi.1008577] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 07/29/2021] [Accepted: 06/04/2021] [Indexed: 12/23/2022] Open
Abstract
Although drug resistance in Plasmodium falciparum typically evolves in regions of low transmission, resistance spreads readily following introduction to regions with a heavier disease burden. This suggests that the origin and the spread of resistance are governed by different processes, and that high transmission intensity specifically impedes the origin. Factors associated with high transmission, such as highly immune hosts and competition within genetically diverse infections, are associated with suppression of resistant lineages within hosts. However, interactions between these factors have rarely been investigated and the specific relationship between adaptive immunity and selection for resistance has not been explored. Here, we developed a multiscale, agent-based model of Plasmodium parasites, hosts, and vectors to examine how host and parasite dynamics shape the evolution of resistance in populations with different transmission intensities. We found that selection for antigenic novelty (“immune selection”) suppressed the evolution of resistance in high transmission settings. We show that high levels of population immunity increased the strength of immune selection relative to selection for resistance. As a result, immune selection delayed the evolution of resistance in high transmission populations by allowing novel, sensitive lineages to remain in circulation at the expense of the spread of a resistant lineage. In contrast, in low transmission settings, we observed that resistant strains were able to sweep to high population prevalence without interference. Additionally, we found that the relationship between immune selection and resistance changed when resistance was widespread. Once resistance was common enough to be found on many antigenic backgrounds, immune selection stably maintained resistant parasites in the population by allowing them to proliferate, even in untreated hosts, when resistance was linked to a novel epitope. Our results suggest that immune selection plays a role in the global pattern of resistance evolution. Drug resistance in the malaria parasite, Plasmodium falciparum, presents an ongoing public health challenge, but aspects of its evolution are poorly understood. Although antimalarial resistance is common worldwide, it can typically be traced to just a handful of evolutionary origins. Counterintuitively, although Sub Saharan Africa bears 90% of the global malaria burden, resistance typically originates in regions where transmission intensity is low. In high transmission regions, infections are genetically diverse, and hosts have significant standing adaptive immunity, both of which are known to suppress the frequency of resistance within infections. However, interactions between immune-driven selection, transmission intensity, and resistance have not been investigated. Using a multiscale, agent-based model, we found that high transmission intensity slowed the evolution of resistance via its effect on host population immunity. High host immunity strengthened selection for antigenic novelty, interfering with selection for resistance and allowing sensitive lineages to suppress resistant lineages in untreated hosts. However, once resistance was common in the circulating parasite population, immune selection maintained it in the population at a high prevalence. Our findings provide a novel explanation for observations about the origin of resistance and suggest that adaptive immunity is a critical component of selection.
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Affiliation(s)
| | - Jonathan J. Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Nicole Mideo
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Canada
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Msellem M, Morris U, Soe A, Abbas FB, Ali AW, Barnes R, Frumento P, Ali AS, Mårtensson A, Björkman A. Increased Sensitivity of Plasmodium falciparum to Artesunate/Amodiaquine Despite 14 Years as First-Line Malaria Treatment, Zanzibar. Emerg Infect Dis 2021; 26:1767-1777. [PMID: 32687050 PMCID: PMC7392451 DOI: 10.3201/eid2608.191547] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Artemisinin-based combination therapies (ACTs) are first-line treatments for uncomplicated Plasmodium falciparum malaria. ACT resistance is spreading in Asia but not yet in Africa. Reduced effects of ACT partner drugs have been reported but with little information regarding widely used artesunate/amodiaquine (ASAQ). We studied its efficacy in Zanzibar after 14 years as first-line treatment directly by an in vivo, single-armed trial and indirectly by prevalences of different genotypes in the P. falciparum chloroquine-resistance transporter, multidrug-resistance 1, and Kelch 13 propeller domain genes. In vivo efficacy was higher during 2017 (100%; 95% CI 97.4%-100%) than during 2002-2005 (94.7%; 95% CI 91.9%-96.7%) (p = 0.003). Molecular findings showed no artemisinin resistance-associated genotypes and major increases in genotypes associated with high sensitivity/efficacy for amodiaquine than before ASAQ was introduced. Thus, the efficacy of ASAQ is maintained and appears to be increased after long-term use in contrast to what is observed for other ACTs used in Africa.
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12
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Duffey M, Blasco B, Burrows JN, Wells TNC, Fidock DA, Leroy D. Assessing risks of Plasmodium falciparum resistance to select next-generation antimalarials. Trends Parasitol 2021; 37:709-721. [PMID: 34001441 DOI: 10.1016/j.pt.2021.04.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/01/2021] [Accepted: 04/08/2021] [Indexed: 02/07/2023]
Abstract
Strategies to counteract or prevent emerging drug resistance are crucial for the design of next-generation antimalarials. In the past, resistant parasites were generally identified following treatment failures in patients, and compounds would have to be abandoned late in development. An early understanding of how candidate therapeutics lose efficacy as parasites evolve resistance is important to facilitate drug design and improve resistance detection and monitoring up to the postregistration phase. We describe a new strategy to assess resistance to antimalarial compounds as early as possible in preclinical development by leveraging tools to define the Plasmodium falciparum resistome, predict potential resistance risks of clinical failure for candidate therapeutics, and inform decisions to guide antimalarial drug development.
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Affiliation(s)
| | - Benjamin Blasco
- Medicines for Malaria Venture, Geneva, Switzerland; Global Antibiotic Research and Development Partnership, Geneva, Switzerland
| | | | | | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA; Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland.
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Tandoh KZ, Wilson MD, Quashie NB, Duah-Quashie NO. Implicating extracellular vesicles in Plasmodium falciparum artemisinin resistance development. Traffic 2021; 22:194-200. [PMID: 33860593 DOI: 10.1111/tra.12787] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 04/10/2021] [Accepted: 04/13/2021] [Indexed: 01/08/2023]
Abstract
Plasmodium falciparum malaria remains a disease of significant public health impact today. With the risk of emerging artemisinin resistance stalling malaria control efforts, the need to deepen our understanding of the parasite's biology is dire. Extracellular vesicles (EVs) are vital to the biology of P. falciparum and play a role in the pathogenesis of malaria. Recent studies have also shown that EVs may play a role in the development of artemisinin resistance in P. falciparum. Here, we highlight evidence on EVs in P. falciparum biology and malaria pathogenesis and argue that there is sufficient ground to propose a role for EVs in the development of P. falciparum artemisinin resistance. We suggest that EVs are actively secreted functional organelles that contribute to cellular homeostasis in P. falciparum-infected red blood cells under artemisinin pressure. Further exploration of this hypothesized EVs-based molecular mechanism of artemisinin resistance will aid the discovery of novel antimalarial therapies.
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Affiliation(s)
- Kwesi Z Tandoh
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Michael D Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Neils B Quashie
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana.,Centre for Tropical Clinical Pharmacology and Therapeutics, School of Medicine and Dentistry, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Nancy O Duah-Quashie
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
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14
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Oriero EC, Amenga-Etego L, Ishengoma DS, Amambua-Ngwa A. Plasmodium malariae, current knowledge and future research opportunities on a neglected malaria parasite species. Crit Rev Microbiol 2021; 47:44-56. [PMID: 33507842 DOI: 10.1080/1040841x.2020.1838440] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Plasmodium malariae is often reported as a benign malaria parasite. There are limited data on its biology and disease burden in sub-Saharan Africa (sSA) possibly due to the unavailability of specific and affordable tools for routine diagnosis and large epidemiology studies. In addition, P. malariae occurs at low parasite densities and in co-infections with other species, predominately P. falciparum. The paucity of data on P. malariae infections limits the capacity to accurately determine its contribution to malaria and the effect of control interventions against P. falciparum on its prevalence. Here, we summarise the current knowledge on P. malariae epidemiology in sSA - overall prevalence ranging from 0-32%, as detected by different diagnostic methods; seroprevalence ranging from 0-56% in three countries (Mozambique, Benin and Zimbabwe), and explore the future application of next-generation sequencing technologies as a tool for enriching P. malariae genomic epidemiology. This will provide insights into important adaptive mechanisms of this neglected non-falciparum species, including antimalarial drug resistance, local and regional parasite transmission patterns and genomic signatures of selection. Improved diagnosis and genomic surveillance of non-falciparum malaria parasites in Africa would be helpful in evaluating progress towards elimination of all human Plasmodium species.
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Affiliation(s)
- Eniyou C Oriero
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at LSHTM, Fajara, The Gambia
| | - Lucas Amenga-Etego
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana
| | - Deus S Ishengoma
- Tanga Research Centre, National Institute for Medical Research, Tanga, Tanzania
| | - Alfred Amambua-Ngwa
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at LSHTM, Fajara, The Gambia
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15
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Imidocarb Dipropionate Lacks Efficacy against Theileria haneyi and Fails to Consistently Clear Theileria equi in Horses Co-Infected with T. haneyi. Pathogens 2020; 9:pathogens9121035. [PMID: 33321715 PMCID: PMC7764667 DOI: 10.3390/pathogens9121035] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/05/2020] [Accepted: 12/08/2020] [Indexed: 12/27/2022] Open
Abstract
Control of Theileria equi, the primary cause of equine theileriosis, is largely reliant on acaracide use and chemosterilization with imidocarb dipropionate (ID). However, it is currently unknown if ID is effective against Theileria haneyi, the recently identified second causative agent of equine theileriosis, or if the drug maintains effectiveness against T. equi in the presence of T. haneyi co-infection. The purpose of this study was to address these questions using ID treatment of the following three groups of horses: (1) five T. haneyi infected horses; (2) three T. haneyi-T. equi infected horses; and (3) three T. equi-T. haneyi infected horses. Clearance was first evaluated using nPCR for each Theileria sp. on peripheral blood samples. ID failed to clear T. haneyi in all three groups of horses, and failed to clear T. equi in two of three horses in group two. For definitive confirmation of infection status, horses in groups two and three underwent splenectomy post-treatment. The T. equi-nPCR-positive horses in group two developed severe clinical signs and were euthanized. Remaining horses exhibited moderate signs consistent with T. haneyi. Our results demonstrate that ID therapy lacks efficacy against T. haneyi, and T. haneyi-T. equi co-infection may interfere with ID clearance of T. equi.
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16
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Acosta MM, Bram JT, Sim D, Read AF. Effect of drug dose and timing of treatment on the emergence of drug resistance in vivo in a malaria model. Evol Med Public Health 2020; 2020:196-210. [PMID: 33209305 PMCID: PMC7652304 DOI: 10.1093/emph/eoaa016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 05/15/2020] [Accepted: 05/26/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND OBJECTIVES There is a significant interest in identifying clinically effective drug treatment regimens that minimize the de novo evolution of antimicrobial resistance in pathogen populations. However, in vivo studies that vary treatment regimens and directly measure drug resistance evolution are rare. Here, we experimentally investigate the role of drug dose and treatment timing on resistance evolution in an animal model. METHODOLOGY In a series of experiments, we measured the emergence of atovaquone-resistant mutants of Plasmodium chabaudi in laboratory mice, as a function of dose or timing of treatment (day post-infection) with the antimalarial drug atovaquone. RESULTS The likelihood of high-level resistance emergence increased with atovaquone dose. When varying the timing of treatment, treating either very early or late in infection reduced the risk of resistance. When we varied starting inoculum, resistance was more likely at intermediate inoculum sizes, which correlated with the largest population sizes at time of treatment. CONCLUSIONS AND IMPLICATIONS (i) Higher doses do not always minimize resistance emergence and can promote the emergence of high-level resistance. (ii) Altering treatment timing affects the risk of resistance emergence, likely due to the size of the population at the time of treatment, although we did not test the effect of immunity whose influence may have been important in the case of late treatment. (iii) Finding the 'right' dose and 'right' time to maximize clinical gains and limit resistance emergence can vary depending on biological context and was non-trivial even in our simplified experiments. LAY SUMMARY In a mouse model of malaria, higher drug doses led to increases in drug resistance. The timing of drug treatment also impacted resistance emergence, likely due to the size of the population at the time of treatment.
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Affiliation(s)
- Mónica M Acosta
- Department of Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA
| | - Joshua T Bram
- Department of Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA
| | - Derek Sim
- Department of Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA
| | - Andrew F Read
- Department of Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
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17
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Ryan N, Anderson K, Volpedo G, Varikuti S, Satoskar M, Satoskar S, Oghumu S. The IL-33/ST2 Axis in Immune Responses Against Parasitic Disease: Potential Therapeutic Applications. Front Cell Infect Microbiol 2020; 10:153. [PMID: 32363166 PMCID: PMC7180392 DOI: 10.3389/fcimb.2020.00153] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 03/23/2020] [Indexed: 12/15/2022] Open
Abstract
Parasitic infections pose a wide and varying threat globally, impacting over 25% of the global population with many more at risk of infection. These infections are comprised of, but not limited to, toxoplasmosis, malaria, leishmaniasis and any one of a wide variety of helminthic infections. While a great deal is understood about the adaptive immune response to each of these parasites, there remains a need to further elucidate the early innate immune response. Interleukin-33 is being revealed as one of the earliest players in the cytokine milieu responding to parasitic invasion, and as such has been given the name "alarmin." A nuclear cytokine, interleukin-33 is housed primarily within epithelial and fibroblastic tissues and is released upon cellular damage or death. Evidence has shown that interleukin-33 seems to play a crucial role in priming the immune system toward a strong T helper type 2 immune response, necessary in the clearance of some parasites, while disease exacerbating in the context of others. With the possibility of being a double-edged sword, a great deal remains to be seen in how interleukin-33 and its receptor ST2 are involved in the immune response different parasites elicit, and how those parasites may manipulate or evade this host mechanism. In this review article we compile the current cutting-edge research into the interleukin-33 response to toxoplasmosis, malaria, leishmania, and helminthic infection. Furthermore, we provide insight into directions interleukin-33 research may take in the future, potential immunotherapeutic applications of interleukin-33 modulation and how a better clarity of early innate immune system responses involving interleukin-33/ST2 signaling may be applied in development of much needed treatment options against parasitic invaders.
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Affiliation(s)
- Nathan Ryan
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Division of Anatomy, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Kelvin Anderson
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Greta Volpedo
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- Department of Microbiology, The Ohio State University, Columbus, OH, United States
| | - Sanjay Varikuti
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Monika Satoskar
- Northeast Ohio Medical University, Rootstown, OH, United States
| | - Sanika Satoskar
- Northeast Ohio Medical University, Rootstown, OH, United States
| | - Steve Oghumu
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
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18
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Karbwang J, Na‐Bangchang K. The Role of Clinical Pharmacology in Chemotherapy of Multidrug‐Resistant
Plasmodium falciparum. J Clin Pharmacol 2020; 60:830-847. [DOI: 10.1002/jcph.1589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 01/21/2020] [Indexed: 01/02/2023]
Affiliation(s)
- Juntra Karbwang
- Graduate Program in Bioclinical SciencesChulabhorn International College of MedicineThammasat University (Rangsit Campus) Pathumthani Thailand
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and CholangiocarcinomaThammasat University (Rangsit Campus) Pathumthani Thailand
- Drug Discovery and Development Center, Office of Advanced Science and TechnologyThammasat University (Rangsit Campus) Pathumthani Thailand
- Department of Clinical Product developmentNagasaki Institute of Tropical MedicineNagasaki University Nagasaki Japan
| | - Kesara Na‐Bangchang
- Graduate Program in Bioclinical SciencesChulabhorn International College of MedicineThammasat University (Rangsit Campus) Pathumthani Thailand
- Center of Excellence in Pharmacology and Molecular Biology of Malaria and CholangiocarcinomaThammasat University (Rangsit Campus) Pathumthani Thailand
- Drug Discovery and Development Center, Office of Advanced Science and TechnologyThammasat University (Rangsit Campus) Pathumthani Thailand
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19
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DNA recovery from archived RDTs for genetic characterization of Plasmodium falciparum in a routine setting in Lambaréné, Gabon. Malar J 2019; 18:336. [PMID: 31578142 PMCID: PMC6775649 DOI: 10.1186/s12936-019-2972-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/24/2019] [Indexed: 11/15/2022] Open
Abstract
Background Rapid diagnostic tests (RDTs) have been described as a source of genetic material to analyse malaria parasites in proof-of-concept studies. The increasing use of RDTs (e.g., in focal or mass screening and treatment campaigns) makes this approach particularly attractive for large-scale investigations of parasite populations. In this study, the complexity of Plasmodium falciparum infections, parasite load and chloroquine resistance transporter gene mutations were investigated in DNA samples extracted from positive RDTs, obtained in a routine setting and archived at ambient temperature. Methods A total of 669 archived RDTs collected from malaria cases in urban, semi-urban and rural areas of central Gabon were used for P. falciparum DNA extraction. Performance of RDTs as a source of DNA for PCR was determined using: (i) amplification of a single copy merozoite surface protein 1 (msp1) gene followed by highly sensitive and automated capillary electrophoresis; (ii) genotyping of the pfcrt gene locus 72–76 using haplotype-specific-probe-based real-time PCR to characterize chloroquine resistance; and, (iii) real-time PCR targeting 18S genes to detect and quantify Plasmodium parasites. Results Out of the 669 archived RDTs, amplification of P. falciparum nucleic materials had a success rate of 97% for 18S real-time PCR, and 88% for the msp1 gene. The multiplicity of infections (MOI) of the whole population was 2.6 (95% CI 2.5–2.8). The highest number of alleles detected in one infection was 11. The MOI decreased with increasing age (β = − 0.0046, p = 0.02) and residence in Lambaréné was associated with smaller MOIs (p < 0.001). The overall prevalence of mutations associated with chloroquine resistance was 78.5% and was not associated with age. In Lambaréné, prevalence of chloroquine resistance was lower compared to rural Moyen-Ogooué (β = − 0.809, p-value = 0.011). Conclusion RDT is a reliable source of DNA for P. falciparum detection and genotyping assays. Furthermore, the increasing use of RDTs allows them to be an alternative source of DNA for large-scale genetic epidemiological studies. Parasite populations in the study area are highly diverse and prevalence of chloroquine-resistant P. falciparum remains high, especially in rural areas.
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20
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Tirrell AR, Vendrely KM, Checkley LA, Davis SZ, McDew-White M, Cheeseman IH, Vaughan AM, Nosten FH, Anderson TJC, Ferdig MT. Pairwise growth competitions identify relative fitness relationships among artemisinin resistant Plasmodium falciparum field isolates. Malar J 2019; 18:295. [PMID: 31462253 PMCID: PMC6714446 DOI: 10.1186/s12936-019-2934-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/23/2019] [Indexed: 02/08/2023] Open
Abstract
Background Competitive outcomes between co-infecting malaria parasite lines can reveal fitness disparities in blood stage growth. Blood stage fitness costs often accompany the evolution of drug resistance, with the expectation that relatively fitter parasites will be more likely to spread in populations. With the recent emergence of artemisinin resistance, it is important to understand the relative competitive fitness of the metabolically active asexual blood stage parasites. Genetically distinct drug resistant parasite clones with independently evolved sets of mutations are likely to vary in asexual proliferation rate, contributing to their chance of transmission to the mosquito vector. Methods An optimized in vitro 96-well plate-based protocol was used to quantitatively measure-head-to-head competitive fitness during blood stage development between seven genetically distinct field isolates from a hotspot of emerging artemisinin resistance and the laboratory strain, NF54. These field isolates were isolated from patients in Southeast Asia carrying different alleles of kelch13 and included both artemisinin-sensitive and artemisinin-resistant isolates. Fluorescent labeled microsatellite markers were used to track the relative densities of each parasite throughout the co-growth period of 14–60 days. All-on-all competitions were conducted for the panel of eight parasite lines (28 pairwise competitions) to determine their quantitative competitive fitness relationships. Results Twenty-eight pairwise competitive growth outcomes allowed for an unambiguous ranking among a set of seven genetically distinct parasite lines isolated from patients in Southeast Asia displaying a range of both kelch13 alleles and clinical clearance times and a laboratory strain, NF54. This comprehensive series of assays established the growth relationships among the eight parasite lines. Interestingly, a clinically artemisinin resistant parasite line that carries the wild-type form of kelch13 outcompeted all other parasites in this study. Furthermore, a kelch13 mutant line (E252Q) was competitively more fit without drug than lines with other resistance-associated kelch13 alleles, including the C580Y allele that has expanded to high frequencies under drug pressure in Southeast Asian resistant populations. Conclusions This optimized competitive growth assay can be employed for assessment of relative growth as an index of fitness during the asexual blood stage growth between natural lines carrying different genetic variants associated with artemisinin resistance. Improved understanding of the fitness costs of different parasites proliferating in human blood and the role different resistance mutations play in the context of specific genetic backgrounds will contribute to an understanding of the potential for specific mutations to spread in populations, with the potential to inform targeted strategies for malaria therapy.
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Affiliation(s)
- Abigail R Tirrell
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Katelyn M Vendrely
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Lisa A Checkley
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Sage Z Davis
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | | | | | | | - François H Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | | | - Michael T Ferdig
- Eck Institute for Global Health, Dept. of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.
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21
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Zhu SJ, Hendry JA, Almagro-Garcia J, Pearson RD, Amato R, Miles A, Weiss DJ, Lucas TC, Nguyen M, Gething PW, Kwiatkowski D, McVean G. The origins and relatedness structure of mixed infections vary with local prevalence of P. falciparum malaria. eLife 2019; 8:e40845. [PMID: 31298657 PMCID: PMC6684230 DOI: 10.7554/elife.40845] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 07/10/2019] [Indexed: 02/07/2023] Open
Abstract
Individual malaria infections can carry multiple strains of Plasmodium falciparum with varying levels of relatedness. Yet, how local epidemiology affects the properties of such mixed infections remains unclear. Here, we develop an enhanced method for strain deconvolution from genome sequencing data, which estimates the number of strains, their proportions, identity-by-descent (IBD) profiles and individual haplotypes. Applying it to the Pf3k data set, we find that the rate of mixed infection varies from 29% to 63% across countries and that 51% of mixed infections involve more than two strains. Furthermore, we estimate that 47% of symptomatic dual infections contain sibling strains likely to have been co-transmitted from a single mosquito, and find evidence of mixed infections propagated over successive infection cycles. Finally, leveraging data from the Malaria Atlas Project, we find that prevalence correlates within Africa, but not Asia, with both the rate of mixed infection and the level of IBD.
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Affiliation(s)
- Sha Joe Zhu
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Jason A Hendry
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Jacob Almagro-Garcia
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Medical Research Council Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Richard D Pearson
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Medical Research Council Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Roberto Amato
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Medical Research Council Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Alistair Miles
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Medical Research Council Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Daniel J Weiss
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Tim Cd Lucas
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Michele Nguyen
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Peter W Gething
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Dominic Kwiatkowski
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Medical Research Council Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Gil McVean
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
- Medical Research Council Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom
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22
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Woldearegai TG, Lalremruata A, Nguyen TT, Gmeiner M, Veletzky L, Tazemda-Kuitsouc GB, Matsiegui PB, Mordmüller B, Held J. Characterization of Plasmodium infections among inhabitants of rural areas in Gabon. Sci Rep 2019; 9:9784. [PMID: 31278305 PMCID: PMC6611864 DOI: 10.1038/s41598-019-46194-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/25/2019] [Indexed: 12/18/2022] Open
Abstract
Plasmodium infections in endemic areas are often asymptomatic, can be caused by different species and contribute significantly to transmission. We performed a cross-sectional study in February/March 2016 including 840 individuals ≥ 1 year living in rural Gabon (Ngounié and Moyen-Ogooué). Plasmodium parasitemia was measured by high-sensitive, real-time quantitative PCR. In a randomly chosen subset of P. falciparum infections, gametocyte carriage and prevalence of chloroquine-resistant genotypes were analysed. 618/834 (74%) individuals were positive for Plasmodium 18S-rRNA gene amplification, of these 553 (66.3%) carried P. falciparum, 193 (23%) P. malariae, 74 (8.9%) P. ovale curtisi and 38 (4.6%) P.ovale wallikeri. Non-falciparum infections mostly presented as mixed infections. P. malariae monoinfected individuals were significantly older (median age: 60 years) than coinfected (20 years) or P. falciparum monoinfected individuals (23 years). P. falciparum gametocyte carriage was confirmed in 109/223 (48.9%) individuals, prevalence of chloroquine-resistant genotypes was high (298/336, 89%), including four infections with a new SVMNK genotype. In rural Gabon, Plasmodium infections with all endemic species are frequent, emphasizing that malaria control efforts shall cover asymptomatic infections also including non-falciparum infections when aiming for eradication.
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Affiliation(s)
- Tamirat Gebru Woldearegai
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Albert Lalremruata
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - The Trong Nguyen
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Vietnamese - German Center of Excellence in Medical Research, Hanoi, Vietnam
| | - Markus Gmeiner
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Luzia Veletzky
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Pierre Blaise Matsiegui
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Centre de Recherches Médicales de la Ngounié, Fougamou, Gabon
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Jana Held
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany. .,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany. .,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.
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23
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Apinjoh TO, Ouattara A, Titanji VPK, Djimde A, Amambua-Ngwa A. Genetic diversity and drug resistance surveillance of Plasmodium falciparum for malaria elimination: is there an ideal tool for resource-limited sub-Saharan Africa? Malar J 2019; 18:217. [PMID: 31242921 PMCID: PMC6595576 DOI: 10.1186/s12936-019-2844-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 06/18/2019] [Indexed: 12/20/2022] Open
Abstract
The intensification of malaria control interventions has resulted in its global decline, but it remains a significant public health burden especially in sub-Saharan Africa (sSA). Knowledge on the parasite diversity, its transmission dynamics, mechanisms of adaptation to environmental and interventional pressures could help refine or develop new control and elimination strategies. Critical to this is the accurate assessment of the parasite’s genetic diversity and monitoring of genetic markers of anti-malarial resistance across all susceptible populations. Such wide molecular surveillance will require selected tools and approaches from a variety of ever evolving advancements in technology and the changing epidemiology of malaria. The choice of an effective approach for specific endemic settings remains challenging, particularly for countries in sSA with limited access to advanced technologies. This article examines the current strategies and tools for Plasmodium falciparum genetic diversity typing and resistance monitoring and proposes how the different tools could be employed in resource-poor settings. Advanced approaches enabling targeted deep sequencing is valued as a sensitive method for assessing drug resistance and parasite diversity but remains out of the reach of most laboratories in sSA due to the high cost of development and maintenance. It is, however, feasible to equip a limited number of laboratories as Centres of Excellence in Africa (CEA), which will receive and process samples from a network of peripheral laboratories in the continent. Cheaper, sensitive and portable real-time PCR methods can be used in peripheral laboratories to pre-screen and select samples for targeted deep sequence or genome wide analyses at these CEAs.
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Affiliation(s)
- Tobias O Apinjoh
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon
| | - Amed Ouattara
- School of Medicine, University of Maryland, College Park, Baltimore, USA
| | - Vincent P K Titanji
- Faculty of Science, Engineering and Technology, Cameroon Christian University, Bali, Cameroon
| | - Abdoulaye Djimde
- Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
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24
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Orwa TO, Mbogo RW, Luboobi LS. Multiple-Strain Malaria Infection and Its Impacts on Plasmodium falciparum Resistance to Antimalarial Therapy: A Mathematical Modelling Perspective. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2019; 2019:9783986. [PMID: 31341510 PMCID: PMC6594251 DOI: 10.1155/2019/9783986] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/15/2019] [Indexed: 11/18/2022]
Abstract
The emergence of parasite resistance to antimalarial drugs has contributed significantly to global human mortality and morbidity due to malaria infection. The impacts of multiple-strain malarial parasite infection have further generated a lot of scientific interest. In this paper, we demonstrate, using the epidemiological model, the effects of parasite resistance and competition between the strains on the dynamics and control of Plasmodium falciparum malaria. The analysed model has a trivial equilibrium point which is locally asymptotically stable when the parasite's effective reproduction number is less than unity. Using contour plots, we observed that the efficacy of antimalarial drugs used, the rate of development of resistance, and the rate of infection by merozoites are the most important parameters in the multiple-strain P. falciparum infection and control model. Although the drug-resistant strain is shown to be less fit, the presence of both strains in the human host has a huge impact on the cost and success of antimalarial treatment. To reduce the emergence of resistant strains, it is vital that only effective antimalarial drugs are administered to patients in hospitals, especially in malaria-endemic regions. Our results emphasize the call for regular and strict surveillance on the use and distribution of antimalarial drugs in health facilities in malaria-endemic countries.
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Affiliation(s)
- Titus Okello Orwa
- Institute of Mathematical Sciences, Strathmore University, P.O. Box 59857-00200, Nairobi, Kenya
| | - Rachel Waema Mbogo
- Institute of Mathematical Sciences, Strathmore University, P.O. Box 59857-00200, Nairobi, Kenya
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25
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Abukari Z, Okonu R, Nyarko SB, Lo AC, Dieng CC, Salifu SP, Gyan BA, Lo E, Amoah LE. The Diversity, Multiplicity of Infection and Population Structure of P. falciparum Parasites Circulating in Asymptomatic Carriers Living in High and Low Malaria Transmission Settings of Ghana. Genes (Basel) 2019; 10:genes10060434. [PMID: 31181699 PMCID: PMC6628376 DOI: 10.3390/genes10060434] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 11/24/2022] Open
Abstract
Background: Diversity in Plasmodium falciparum poses a major threat to malaria control and elimination interventions. This study utilized 12 polymorphic microsatellite (MS) markers and the Msp2 marker to examine diversity, multiplicity of infection (MOI) as well as the population structure of parasites circulating in two sites separated by about 92 km and with varying malaria transmission intensities within the Greater Accra Region of Ghana. Methods: The diversity and MOI of P. falciparum parasites in 160 non-symptomatic volunteers living in Obom (high malaria transmission intensity) and Asutsuare (low malaria transmission intensity) aged between 8 and 60 years was determined using Msp2 genotyping and microsatellite analysis. Results: The prevalence of asymptomatic P. falciparum carriers as well as the parasite density of infections was significantly higher in Obom than in Asutsuare. Samples from Asutsuare and Obom were 100% and 65% clonal, respectively, by Msp2 genotyping but decreased to 50% and 5%, respectively, when determined by MS analysis. The genetic composition of parasites from Obom and Asutsuare were highly distinct, with parasites from Obom being more diverse than those from Asutsuare. Conclusion: Plasmodium falciparum parasites circulating in Obom are genetically more diverse and distinct from those circulating in Asutsuare. The MOI in samples from both Obom and Asutsuare increased when assessed by MS analysis relative to MSP2 genotyping. The TA40 and TA87 loci are useful markers for estimating MOI in high and low parasite prevalence settings.
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Affiliation(s)
- Zakaria Abukari
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
| | - Ruth Okonu
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
| | - Samuel B Nyarko
- School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana.
| | - Aminata C Lo
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
- Department of Parasitology, University Cheikh Anta Diop, Dakar, Senegal.
| | - Cheikh C Dieng
- Department of Biological Sciences, University of North Carolina at Charlotte, NC 28223, USA.
| | - Samson P Salifu
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Ben A Gyan
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
| | - Eugenia Lo
- Department of Biological Sciences, University of North Carolina at Charlotte, NC 28223, USA.
| | - Linda E Amoah
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
- West Africa Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana.
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26
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Lee TE, Penny MA. Identifying key factors of the transmission dynamics of drug-resistant malaria. J Theor Biol 2019; 462:210-220. [DOI: 10.1016/j.jtbi.2018.10.050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/15/2018] [Accepted: 10/25/2018] [Indexed: 11/30/2022]
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Sondo P, Derra K, Lefevre T, Diallo-Nakanabo S, Tarnagda Z, Zampa O, Kazienga A, Valea I, Sorgho H, Ouedraogo JB, Guiguemde TR, Tinto H. Genetically diverse Plasmodium falciparum infections, within-host competition and symptomatic malaria in humans. Sci Rep 2019; 9:127. [PMID: 30644435 PMCID: PMC6333925 DOI: 10.1038/s41598-018-36493-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 11/16/2018] [Indexed: 11/17/2022] Open
Abstract
There is a large genetic diversity of Plasmodium falciparum strains that infect people causing diverse malaria symptoms. This study was carried out to explore the effect of mixed-strain infections and the extent to which some specific P. falciparum variants are associated with particular malaria symptoms. P. falciparum isolates collected during pharmacovigilance study in Nanoro, Burkina Faso were used to determine allelic variation in two polymorphic antigens of the merozoite surface (msp1 and msp2). Overall, parasite density did not increase with additional strains, suggesting the existence of within-host competition. Parasite density was influenced by msp1 allelic families with highest parasitaemia observed in MAD20 allelic family. However, when in mixed infections with allelic family K1, MAD20 could not grow to the same levels as it would alone, suggesting competitive suppression in these mixed infections. Host age was associated with parasite density. Overall, older patients exhibited lower parasite densities than younger patients, but this effect varied with the genetic composition of the isolates for the msp1 gene. There was no effect of msp1 and msp2 allelic family variation on body temperature. Haemoglobin level was influenced by msp2 family with patients harboring the FC27 allele showing lower haemoglobin level than mono-infected individuals by the 3D7 allele. This study provides evidence that P. falciparum genetic diversity influenced the severity of particular malaria symptoms and supports the existence of within-host competition in genetically diverse P. falciparum.
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Affiliation(s)
- Paul Sondo
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso.
| | - Karim Derra
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | - Thierry Lefevre
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso.,MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Seydou Diallo-Nakanabo
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | - Zekiba Tarnagda
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | - Odile Zampa
- Centre Muraz of Bobo-Dioulasso, Bobo-Dioulasso, Burkina Faso
| | - Adama Kazienga
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | - Innocent Valea
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso.,Centre Muraz of Bobo-Dioulasso, Bobo-Dioulasso, Burkina Faso
| | - Hermann Sorgho
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | - Jean-Bosco Ouedraogo
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | | | - Halidou Tinto
- Institut de Recherche en Sciences de la Santé (IRSS)/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso.,Centre Muraz of Bobo-Dioulasso, Bobo-Dioulasso, Burkina Faso
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28
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Bushman M, Antia R, Udhayakumar V, de Roode JC. Within-host competition can delay evolution of drug resistance in malaria. PLoS Biol 2018; 16:e2005712. [PMID: 30130363 PMCID: PMC6103507 DOI: 10.1371/journal.pbio.2005712] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 07/16/2018] [Indexed: 12/21/2022] Open
Abstract
In the malaria parasite P. falciparum, drug resistance generally evolves first in low-transmission settings, such as Southeast Asia and South America. Resistance takes noticeably longer to appear in the high-transmission settings of sub-Saharan Africa, although it may spread rapidly thereafter. Here, we test the hypothesis that competitive suppression of drug-resistant parasites by drug-sensitive parasites may inhibit evolution of resistance in high-transmission settings, where mixed-strain infections are common. We employ a cross-scale model, which simulates within-host (infection) dynamics and between-host (transmission) dynamics of sensitive and resistant parasites for a population of humans and mosquitoes. Using this model, we examine the effects of transmission intensity, selection pressure, fitness costs of resistance, and cross-reactivity between strains on the establishment and spread of resistant parasites. We find that resistant parasites, introduced into the population at a low frequency, are more likely to go extinct in high-transmission settings, where drug-sensitive competitors and high levels of acquired immunity reduce the absolute fitness of the resistant parasites. Under strong selection from antimalarial drug use, however, resistance spreads faster in high-transmission settings than low-transmission ones. These contrasting results highlight the distinction between establishment and spread of resistance and suggest that the former but not the latter may be inhibited in high-transmission settings. Our results suggest that within-host competition is a key factor shaping the evolution of drug resistance in P. falciparum. The malaria parasite Plasmodium falciparum has evolved resistance to most antimalarial drugs, greatly complicating treatment and control of the disease. Curiously, although sub-Saharan Africa accounts for the majority of the global burden of malaria, the evolution of drug resistance in Africa has been markedly delayed compared to Asia and the Americas. One reason might be that, in a population in which the prevalence of infection is high, a newly emerged drug-resistant strain faces a high risk of extinction due to competition from drug-sensitive parasites that already “occupy” most of the host population. Using a mathematical model, we confirm that drug-resistant parasites face a much greater risk of extinction in a “high-transmission” setting like sub-Saharan Africa than in a “low-transmission” setting like Southeast Asia. However, we also find that when drug-resistant parasites manage to avoid extinction, their subsequent spread may be more rapid in high-transmission settings than in low-transmission settings, especially when selection is strong. These results offer a novel explanation for global patterns of drug resistance evolution in malaria and suggest a new dimension to consider in resistance prevention and containment efforts: namely, the intrinsic favorability of low- and high-transmission settings for establishment and spread of drug resistance.
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Affiliation(s)
- Mary Bushman
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
| | - Rustom Antia
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Jacobus C. de Roode
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
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29
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Huijben S, Chan BHK, Nelson WA, Read AF. The impact of within-host ecology on the fitness of a drug-resistant parasite. EVOLUTION MEDICINE AND PUBLIC HEALTH 2018; 2018:127-137. [PMID: 30087774 PMCID: PMC6061792 DOI: 10.1093/emph/eoy016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/18/2018] [Indexed: 02/05/2023]
Abstract
Background and objectives The rate of evolution of drug resistance depends on the fitness of resistant pathogens. The fitness of resistant pathogens is reduced by competition with sensitive pathogens in untreated hosts and so enhanced by competitive release in drug-treated hosts. We set out to estimate the magnitude of those effects on a variety of fitness measures, hypothesizing that competitive suppression and competitive release would have larger impacts when resistance was rarer to begin with. Methodology We infected mice with varying densities of drug-resistant Plasmodium chabaudi malaria parasites in a fixed density of drug-sensitive parasites and followed infection dynamics using strain-specific quantitative PCR. Results Competition with susceptible parasites reduced the absolute fitness of resistant parasites by 50–100%. Drug treatment increased the absolute fitness from 2- to >10 000-fold. The ecological context and choice of fitness measure was responsible for the wide variation in those estimates. Initial population growth rates poorly predicted parasite abundance and transmission probabilities. Conclusions and implications (i) The sensitivity of estimates of pathogen fitness to ecological context and choice of fitness measure make it difficult to derive field-relevant estimates of the fitness costs and benefits of resistance from experimental settings. (ii) Competitive suppression can be a key force preventing resistance from emerging when it is rare, as it is when it first arises. (iii) Drug treatment profoundly affects the fitness of resistance. Resistance evolution could be slowed by developing drug use policies that consider in-host competition.
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Affiliation(s)
- Silvie Huijben
- Departments of Biology and Entomology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA
| | - Brian H K Chan
- Departments of Biology and Entomology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA
| | - William A Nelson
- Department of Biology, Queen's University, Kingston, ON K7L3N6, Canada
| | - Andrew F Read
- Departments of Biology and Entomology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA.,Department of Fogarty, National Institutes of Health, Fogarty International Center, Bethesda, MD, USA
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30
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Abstract
Infectious diseases caused by germs, parasites, fungi, virus and bacteria are one of the leading causes of death worldwide. Polymeric therapeutics are nanomedicines that offer several advantages making them useful for the treatment of infectious diseases such as targeted drug release mechanism, ability to maintain the drug concentration within a therapeutic window for a desired duration, biocompatibility with low immunogenicity and reduced drug toxicity resulting in enhanced therapeutic efficacy of the incorporated drug. Although polymeric therapeutics have been evaluated for the treatment of infectious diseases in vitro and in vivo with improved therapeutic efficacy, most treatments for infectious disease have not been evaluated using polymeric therapeutics. This review will focus on the applications of polymeric therapeutics for the treatment of infectious diseases (preclinical studies and clinical trials), with particular focus on parasitic and viral infections.
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31
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Zhong D, Lo E, Wang X, Yewhalaw D, Zhou G, Atieli HE, Githeko A, Hemming-Schroeder E, Lee MC, Afrane Y, Yan G. Multiplicity and molecular epidemiology of Plasmodium vivax and Plasmodium falciparum infections in East Africa. Malar J 2018; 17:185. [PMID: 29720181 PMCID: PMC5932820 DOI: 10.1186/s12936-018-2337-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 04/26/2018] [Indexed: 11/18/2022] Open
Abstract
Background Parasite genetic diversity and multiplicity of infection (MOI) affect clinical outcomes, response to drug treatment and naturally-acquired or vaccine-induced immunity. Traditional methods often underestimate the frequency and diversity of multiclonal infections due to technical sensitivity and specificity. Next-generation sequencing techniques provide a novel opportunity to study complexity of parasite populations and molecular epidemiology. Methods Symptomatic and asymptomatic Plasmodium vivax samples were collected from health centres/hospitals and schools, respectively, from 2011 to 2015 in Ethiopia. Similarly, both symptomatic and asymptomatic Plasmodium falciparum samples were collected, respectively, from hospitals and schools in 2005 and 2015 in Kenya. Finger-pricked blood samples were collected and dried on filter paper. Long amplicon (> 400 bp) deep sequencing of merozoite surface protein 1 (msp1) gene was conducted to determine multiplicity and molecular epidemiology of P. vivax and P. falciparum infections. The results were compared with those based on short amplicon (117 bp) deep sequencing. Results A total of 139 P. vivax and 222 P. falciparum samples were pyro-sequenced for pvmsp1 and pfmsp1, yielding a total of 21 P. vivax and 99 P. falciparum predominant haplotypes. The average MOI for P. vivax and P. falciparum were 2.16 and 2.68, respectively, which were significantly higher than that of microsatellite markers and short amplicon (117 bp) deep sequencing. Multiclonal infections were detected in 62.2% of the samples for P. vivax and 74.8% of the samples for P. falciparum. Four out of the five subjects with recurrent P. vivax malaria were found to be a relapse 44–65 days after clearance of parasites. No difference was observed in MOI among P. vivax patients of different symptoms, ages and genders. Similar patterns were also observed in P. falciparum except for one study site in Kenyan lowland areas with significantly higher MOI. Conclusions The study used a novel method to evaluate Plasmodium MOI and molecular epidemiological patterns by long amplicon ultra-deep sequencing. The complexity of infections were similar among age groups, symptoms, genders, transmission settings (spatial heterogeneity), as well as over years (pre- vs. post-scale-up interventions). This study demonstrated that long amplicon deep sequencing is a useful tool to investigate multiplicity and molecular epidemiology of Plasmodium parasite infections. Electronic supplementary material The online version of this article (10.1186/s12936-018-2337-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA.
| | - Eugenia Lo
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA
| | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA
| | - Harrysone E Atieli
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Andrew Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA
| | - Yaw Afrane
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, CA, 92617, USA.
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32
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Early AM, Lievens M, MacInnis BL, Ockenhouse CF, Volkman SK, Adjei S, Agbenyega T, Ansong D, Gondi S, Greenwood B, Hamel M, Odero C, Otieno K, Otieno W, Owusu-Agyei S, Asante KP, Sorgho H, Tina L, Tinto H, Valea I, Wirth DF, Neafsey DE. Host-mediated selection impacts the diversity of Plasmodium falciparum antigens within infections. Nat Commun 2018; 9:1381. [PMID: 29643376 PMCID: PMC5895824 DOI: 10.1038/s41467-018-03807-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/14/2018] [Indexed: 12/28/2022] Open
Abstract
Host immunity exerts strong selective pressure on pathogens. Population-level genetic analysis can identify signatures of this selection, but these signatures reflect the net selective effect of all hosts and vectors in a population. In contrast, analysis of pathogen diversity within hosts provides information on individual, host-specific selection pressures. Here, we combine these complementary approaches in an analysis of the malaria parasite Plasmodium falciparum using haplotype sequences from thousands of natural infections in sub-Saharan Africa. We find that parasite genotypes show preferential clustering within multi-strain infections in young children, and identify individual amino acid positions that may contribute to strain-specific immunity. Our results demonstrate that natural host defenses to P. falciparum act in an allele-specific manner to block specific parasite haplotypes from establishing blood-stage infections. This selection partially explains the extreme amino acid diversity of many parasite antigens and suggests that vaccines targeting such proteins should account for allele-specific immunity. Host immune responses exert selective pressure on Plasmodium falciparum. Here, the authors show that allele-specific immunity impacts the antigenic diversity of individual malaria infections. This process partially explains the extreme amino acid diversity of many parasite antigens and suggests that vaccines should account for allele-specific immunity.
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Affiliation(s)
- Angela M Early
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA. .,Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
| | | | - Bronwyn L MacInnis
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | | | - Sarah K Volkman
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.,Simmons College, School of Nursing and Health Sciences, Boston, MA, 02115, USA
| | - Samuel Adjei
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, KNUST - Kumasi, Ghana
| | - Tsiri Agbenyega
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, KNUST - Kumasi, Ghana
| | - Daniel Ansong
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, KNUST - Kumasi, Ghana
| | - Stacey Gondi
- KEMRI-Walter Reed Project, Kombewa, 40102, Kenya
| | - Brian Greenwood
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Mary Hamel
- KEMRI/CDC Research and Public Health Collaboration, Kisumu, 40100, Kenya
| | - Chris Odero
- KEMRI/CDC Research and Public Health Collaboration, Kisumu, 40100, Kenya
| | - Kephas Otieno
- KEMRI/CDC Research and Public Health Collaboration, Kisumu, 40100, Kenya
| | | | - Seth Owusu-Agyei
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.,Kintampo Health Research Centre, Kintampo, 200, Ghana.,University of Health and Allied Science, PMB 31, Ho, Volta Region, Ghana
| | | | - Hermann Sorgho
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso/Institute of Tropical Medicine, 2000, Antwerp, Belgium
| | - Lucas Tina
- KEMRI-Walter Reed Project, Kombewa, 40102, Kenya
| | - Halidou Tinto
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso/Institute of Tropical Medicine, 2000, Antwerp, Belgium
| | - Innocent Valea
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso/Institute of Tropical Medicine, 2000, Antwerp, Belgium
| | - Dyann F Wirth
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Daniel E Neafsey
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA. .,Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
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33
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Miller RH, Hathaway NJ, Kharabora O, Mwandagalirwa K, Tshefu A, Meshnick SR, Taylor SM, Juliano JJ, Stewart VA, Bailey JA. A deep sequencing approach to estimate Plasmodium falciparum complexity of infection (COI) and explore apical membrane antigen 1 diversity. Malar J 2017; 16:490. [PMID: 29246158 PMCID: PMC5732508 DOI: 10.1186/s12936-017-2137-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 12/06/2017] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Humans living in regions with high falciparum malaria transmission intensity harbour multi-strain infections comprised of several genetically distinct malaria haplotypes. The number of distinct malaria parasite haplotypes identified from an infected human host at a given time is referred to as the complexity of infection (COI). In this study, an amplicon-based deep sequencing method targeting the Plasmodium falciparum apical membrane antigen 1 (pfama1) was utilized to (1) investigate the relationship between P. falciparum prevalence and COI, (2) to explore the population genetic structure of P. falciparum parasites from malaria asymptomatic individuals participating in the 2007 Demographic and Health Survey (DHS) in the Democratic Republic of Congo (DRC), and (3) to explore selection pressures on geospatially divergent parasite populations by comparing AMA1 amino acid frequencies in the DRC and Mali. RESULTS A total of 900 P. falciparum infections across 11 DRC provinces were examined. Deep sequencing of both individuals, for COI analysis, and pools of individuals, to examine population structure, identified 77 unique pfama1 haplotypes. The majority of individual infections (64.5%) contained polyclonal (COI > 1) malaria infections based on the presence of genetically distinct pfama1 haplotypes. A minimal correlation between COI and malaria prevalence as determined by sensitive real-time PCR was identified. Population genetic analyses revealed extensive haplotype diversity, the vast majority of which was shared across the sites. AMA1 amino acid frequencies were similar between parasite populations in the DRC and Mali. CONCLUSIONS Amplicon-based deep sequencing is a useful tool for the detection of multi-strain infections that can aid in the understanding of antigen heterogeneity of potential malaria vaccine candidates, population genetics of malaria parasites, and factors that influence complex, polyclonal malaria infections. While AMA1 and other diverse markers under balancing selection may perform well for understanding COI, they may offer little geographic or temporal discrimination between parasite populations.
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Affiliation(s)
- Robin H Miller
- Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD, USA
| | - Nicholas J Hathaway
- Program in Bioinformatics and Integrative Biology, University of Massachusetts School of Medicine, 55 Lake Avenue North, Worcester, MA, USA
| | - Oksana Kharabora
- University of North Carolina School of Medicine, 101 Manning Drive, Chapel Hill, NC, USA
| | - Kashamuka Mwandagalirwa
- Ecole de Santé Publique, Université de Kinshasa, Commune de Lemba, P.O Box 11850, Kinshasa, Democratic Republic of Congo
| | - Antoinette Tshefu
- Ecole de Santé Publique, Université de Kinshasa, Commune de Lemba, P.O Box 11850, Kinshasa, Democratic Republic of Congo
| | - Steven R Meshnick
- University of North Carolina School of Medicine, 101 Manning Drive, Chapel Hill, NC, USA
| | - Steve M Taylor
- Division of Infectious Diseases and Duke Global Health Institute, Duke University Medical Center, 303 Research Drive, Durham, NC, USA
| | - Jonathan J Juliano
- University of North Carolina School of Medicine, 101 Manning Drive, Chapel Hill, NC, USA
| | - V Ann Stewart
- Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD, USA
| | - Jeffrey A Bailey
- Program in Bioinformatics and Integrative Biology, University of Massachusetts School of Medicine, 55 Lake Avenue North, Worcester, MA, USA.
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Aderibigbe BA. Metal-Based Nanoparticles for the Treatment of Infectious Diseases. Molecules 2017; 22:E1370. [PMID: 28820471 PMCID: PMC6152252 DOI: 10.3390/molecules22081370] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/15/2017] [Indexed: 11/16/2022] Open
Abstract
Infectious diseases can be transmitted and they cause a significant burden on public health globally. They are the greatest world killers and it is estimated that they are responsible for the demise of over 17 million people annually. The impact of these diseases is greater in the developing countries. People with compromised immune systems and children are the most affected. Infectious diseases may be caused by bacteria, viruses, and protozoa. The treatment of infectious diseases is hampered by simultaneous resistance to multiple drugs, indicating that there is a serious and pressing need to develop new therapeutics that can overcome drug resistance. This review will focus on the recent reports of metal-based nanoparticles that are potential therapeutics for the treatment of infectious diseases and their biological efficacy (in vitro and in vivo).
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Affiliation(s)
- Blessing Atim Aderibigbe
- Department of Chemistry, University of Fort Hare, Alice Campus, Eastern Cape 5700, South Africa.
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35
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Ruizendaal E, Tahita MC, Geskus RB, Versteeg I, Scott S, d'Alessandro U, Lompo P, Derra K, Traore-Coulibaly M, de Jong MD, Schallig HDFH, Tinto H, Mens PF. Increase in the prevalence of mutations associated with sulfadoxine-pyrimethamine resistance in Plasmodium falciparum isolates collected from early to late pregnancy in Nanoro, Burkina Faso. Malar J 2017; 16:179. [PMID: 28454537 PMCID: PMC5410088 DOI: 10.1186/s12936-017-1831-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/23/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pregnant women are a high-risk group for Plasmodium falciparum infections, which may result in maternal anaemia and low birth weight newborns, among other adverse birth outcomes. Intermittent preventive treatment with sulfadoxine-pyrimethamine during pregnancy (IPTp-SP) is widely implemented to prevent these negative effects of malaria. However, resistance against SP by P. falciparum may decrease efficacy of IPTp-SP. Combinations of point mutations in the dhps (codons A437, K540) and dhfr genes (codons N51, C59, S108) of P. falciparum are associated with SP resistance. In this study the prevalence of SP resistance mutations was determined among P. falciparum found in pregnant women and the general population (GP) from Nanoro, Burkina Faso and the association of IPTp-SP dosing and other variables with mutations was studied. METHODS Blood spots on filter papers were collected from pregnant women at their first antenatal care visit (ANC booking) and at delivery, from an ongoing trial and from the GP in a cross-sectional survey. The dhps and dhfr genes were amplified by nested PCR and products were sequenced to identify mutations conferring resistance (ANC booking, n = 400; delivery, n = 223; GP, n = 400). Prevalence was estimated with generalized estimating equations and for multivariate analyses mixed effects logistic regression was used. RESULTS The prevalence of the triple dhfr mutation was high, and significantly higher in the GP and at delivery than at ANC booking, but it did not affect birth weight. Furthermore, quintuple mutations (triple dhfr and double dhps mutations) were found for the first time in Burkina Faso. IPTp-SP did not significantly affect the occurrence of any of the mutations, but high transmission season was associated with increased mutation prevalence in delivery samples. It is unclear why the prevalence of mutations was higher in the GP than in pregnant women at ANC booking. CONCLUSION The high number of mutants and the presence of quintuple mutants in Burkina Faso confirm concerns about the efficacy of IPTp-SP in the near future. Other drug combinations to tackle malaria in pregnancy should, therefore, be explored. An increase in mutation prevalence due to IPTp-SP dosing could not be confirmed.
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Affiliation(s)
- Esmée Ruizendaal
- Department of Medical Microbiology, Academic Medical Centre, Amsterdam, The Netherlands.
| | - Marc C Tahita
- Institut de Recherche en Sciences de la Santé-Unité de Recherche Clinique de Nanoro, (IRSS-URCN), Nanoro, Burkina Faso
| | - Ronald B Geskus
- Department of Clinical Epidemiology, Biostatistic and Bioinformatics, Academic Medical Centre, Amsterdam, The Netherlands.,Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Viet Nam
| | - Inge Versteeg
- Koninklijk Instituut voor de Tropen, Amsterdam, The Netherlands
| | - Susana Scott
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.,Disease Control and Elimination, Medical Research Council Unit, Fajara, Gambia
| | - Umberto d'Alessandro
- Disease Control and Elimination, Medical Research Council Unit, Fajara, Gambia.,Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Palpouguini Lompo
- Institut de Recherche en Sciences de la Santé-Unité de Recherche Clinique de Nanoro, (IRSS-URCN), Nanoro, Burkina Faso
| | - Karim Derra
- Institut de Recherche en Sciences de la Santé-Unité de Recherche Clinique de Nanoro, (IRSS-URCN), Nanoro, Burkina Faso
| | - Maminata Traore-Coulibaly
- Institut de Recherche en Sciences de la Santé-Unité de Recherche Clinique de Nanoro, (IRSS-URCN), Nanoro, Burkina Faso
| | - Menno D de Jong
- Department of Medical Microbiology, Academic Medical Centre, Amsterdam, The Netherlands
| | - Henk D F H Schallig
- Department of Medical Microbiology, Academic Medical Centre, Amsterdam, The Netherlands
| | - Halidou Tinto
- Institut de Recherche en Sciences de la Santé-Unité de Recherche Clinique de Nanoro, (IRSS-URCN), Nanoro, Burkina Faso
| | - Petra F Mens
- Department of Medical Microbiology, Academic Medical Centre, Amsterdam, The Netherlands
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Rogier E, Plucinski M, Lucchi N, Mace K, Chang M, Lemoine JF, Candrinho B, Colborn J, Dimbu R, Fortes F, Udhayakumar V, Barnwell J. Bead-based immunoassay allows sub-picogram detection of histidine-rich protein 2 from Plasmodium falciparum and estimates reliability of malaria rapid diagnostic tests. PLoS One 2017; 12:e0172139. [PMID: 28192523 PMCID: PMC5305216 DOI: 10.1371/journal.pone.0172139] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/31/2017] [Indexed: 11/18/2022] Open
Abstract
Detection of histidine-rich protein 2 (HRP2) from the malaria parasite Plasmodium falciparum provides evidence for active or recent infection, and is utilized for both diagnostic and surveillance purposes, but current laboratory immunoassays for HRP2 are hindered by low sensitivities and high costs. Here we present a new HRP2 immunoassay based on antigen capture through a bead-based system capable of detecting HRP2 at sub-picogram levels. The assay is highly specific and cost-effective, allowing fast processing and screening of large numbers of samples. We utilized the assay to assess results of HRP2-based rapid diagnostic tests (RDTs) in different P. falciparum transmission settings, generating estimates for true performance in the field. Through this method of external validation, HRP2 RDTs were found to perform well in the high-endemic areas of Mozambique and Angola with 86.4% and 73.9% of persons with HRP2 in their blood testing positive by RDTs, respectively, and false-positive rates of 4.3% and 0.5%. However, in the low-endemic setting of Haiti, only 14.5% of persons found to be HRP2 positive by the bead assay were RDT positive. Additionally, 62.5% of Haitians showing a positive RDT test had no detectable HRP2 by the bead assay, likely indicating that these were false positive tests. In addition to RDT validation, HRP2 biomass was assessed for the populations in these different settings, and may provide an additional metric by which to estimate P. falciparum transmission intensity and measure the impact of interventions.
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Affiliation(s)
- Eric Rogier
- The Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, United States of America
- * E-mail:
| | - Mateusz Plucinski
- The Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, United States of America
| | - Naomi Lucchi
- The Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, United States of America
| | - Kimberly Mace
- The Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, United States of America
| | - Michelle Chang
- The Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, United States of America
| | - Jean Frantz Lemoine
- Programme National de Contrôle de la Malaria, Ministère de la Santé Publique et de la Population (MSPP), Port-au-Prince, Haiti
| | | | - James Colborn
- Clinton Health Access Initiative, Boston, Massachusetts, United States of America
| | - Rafael Dimbu
- National Malaria Control Program, Luanda, Angola
| | | | - Venkatachalam Udhayakumar
- The Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, United States of America
| | - John Barnwell
- The Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, United States of America
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Singh GP, Sharma A. South-East Asian strains of Plasmodium falciparum display higher ratio of non-synonymous to synonymous polymorphisms compared to African strains. F1000Res 2016; 5:1964. [PMID: 27853513 PMCID: PMC5089136 DOI: 10.12688/f1000research.9372.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/19/2016] [Indexed: 11/20/2022] Open
Abstract
Resistance to frontline anti-malarial drugs, including artemisinin, has repeatedly arisen in South-East Asia, but the reasons for this are not understood. Here we test whether evolutionary constraints on
Plasmodium falciparum strains from South-East Asia differ from African strains. We find a significantly higher ratio of non-synonymous to synonymous polymorphisms in
P. falciparum from South-East Asia compared to Africa, suggesting differences in the selective constraints on
P. falciparum genome in these geographical regions. Furthermore, South-East Asian strains showed a higher proportion of non-synonymous polymorphism at conserved positions, suggesting reduced negative selection. There was a lower rate of mixed infection by multiple genotypes in samples from South-East Asia compared to Africa. We propose that a lower mixed infection rate in South-East Asia reduces intra-host competition between the parasite clones, reducing the efficiency of natural selection. This might increase the probability of fixation of fitness-reducing mutations including drug resistant ones.
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Affiliation(s)
- Gajinder Pal Singh
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Amit Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
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Impact of exposure to mosquito transmission-blocking antibodies on Plasmodium falciparum population genetic structure. INFECTION GENETICS AND EVOLUTION 2016; 45:138-144. [PMID: 27566334 DOI: 10.1016/j.meegid.2016.08.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/21/2016] [Accepted: 08/22/2016] [Indexed: 01/21/2023]
Abstract
Progress in malaria control has led to a significant reduction of the malaria burden. Interventions that interrupt transmission are now needed to achieve the elimination goal. Transmission-blocking vaccines (TBV) that aim to prevent mosquito infections represent promising tools and several vaccine candidates targeting different stages of the parasite's lifecycle are currently under development. A mosquito-midgut antigen, the anopheline alanyl aminopeptidase (AnAPN1) is one of the lead TBV candidates; antibodies against AnAPN1 prevent ookinete invasion. In this study, we explored the transmission dynamics of Plasmodium falciparum in mosquitoes fed with anti-AnAPN1 monoclonal antibodies (mAbs) vs. untreated controls, and investigated whether the parasite genetic content affects or is affected by antibody treatment. Exposure to anti-AnAPN1 mAbs was efficient at blocking parasite transmission and the effect was dose-dependent. Genetic analysis revealed a significant sib-mating within P. falciparum infra-populations infecting one host, as measured by the strong correlation between Wright's FIS and multiplicity of infection. Treatments also resulted in significant decrease in FIS as a by-product of drop in infra-population genetic diversity and concomitant increase of apparent panmictic genotyping proportions. Genetic differentiation analyses indicated that mosquitoes fed on a same donor randomly sampled blood-circulating gametocytes. We did not detect trace of selection, as the genetic differentiation between different donors did not decrease with increasing mAb concentration and was not significant between treatments for each gametocyte donor. Thus, there is apparently no specific genotype associated with the loss of diversity under mAb treatment. Finally, the anti-AnAPN1 mAbs were effective at reducing mosquito infection and a vaccine aiming at eliciting anti-AnAPN1 mAbs has a strong potential to decrease the burden of malaria in transmission-blocking interventions without any apparent selective pressure on the parasite population.
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