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Zupko RJ, Servadio JL, Nguyen TD, Tran TNA, Tran KT, Somé AF, Boni MF. Role of seasonal importation and genetic drift on selection for drug-resistant genotypes of Plasmodium falciparum in high-transmission settings. J R Soc Interface 2024; 21:20230619. [PMID: 38442861 PMCID: PMC10914515 DOI: 10.1098/rsif.2023.0619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/31/2024] [Indexed: 03/07/2024] Open
Abstract
Historically Plasmodium falciparum has followed a pattern of drug resistance first appearing in low-transmission settings before spreading to high-transmission settings. Several features of low-transmission regions are hypothesized as explanations: higher chance of symptoms and treatment seeking, better treatment access, less within-host competition among clones and lower rates of recombination. Here, we test whether importation of drug-resistant parasites is more likely to lead to successful emergence and establishment in low-transmission or high-transmission periods of the same epidemiological setting, using a spatial, individual-based stochastic model of malaria and drug-resistance evolution calibrated for Burkina Faso. Upon controlling for the timing of importation of drug-resistant genotypes and examination of key model variables, we found that drug-resistant genotypes imported during the low-transmission season were (i) more susceptible to stochastic extinction due to the action of genetic drift, and (ii) more likely to lead to establishment of drug resistance when parasites are able to survive early stochastic loss due to drift. This implies that rare importation events are more likely to lead to establishment if they occur during a high-transmission season, but that constant importation (e.g. neighbouring countries with high levels of resistance) may produce a greater risk during low-transmission periods.
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Affiliation(s)
- Robert J. Zupko
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Joseph L. Servadio
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Tran Dang Nguyen
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Thu Nguyen-Anh Tran
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Kien Trung Tran
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Anyirékun Fabrice Somé
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Bobo Dioulasso, Burkina Faso
| | - Maciej F. Boni
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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2
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Braunack-Mayer L, Malinga J, Masserey T, Nekkab N, Sen S, Schellenberg D, Tchouatieu AM, Kelly SL, Penny MA. Design and selection of drug properties to increase the public health impact of next-generation seasonal malaria chemoprevention: a modelling study. Lancet Glob Health 2024; 12:e478-e490. [PMID: 38365418 PMCID: PMC10882206 DOI: 10.1016/s2214-109x(23)00550-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 10/02/2023] [Accepted: 11/20/2023] [Indexed: 02/18/2024]
Abstract
BACKGROUND Seasonal malaria chemoprevention (SMC) is recommended for disease control in settings with moderate to high Plasmodium falciparum transmission and currently depends on the administration of sulfadoxine-pyrimethamine plus amodiaquine. However, poor regimen adherence and the increased frequency of parasite mutations conferring sulfadoxine-pyrimethamine resistance might threaten the effectiveness of SMC. Guidance is needed to de-risk the development of drug compounds for malaria prevention. We aimed to provide guidance for the early prioritisation of new and alternative SMC drugs and their target product profiles. METHODS In this modelling study, we combined an individual-based malaria transmission model that has explicit parasite growth with drug pharmacokinetic and pharmacodynamic models. We modelled SMC drug attributes for several possible modes of action, linked to their potential public health impact. Global sensitivity analyses identified trade-offs between drug elimination half-life, maximum parasite killing effect, and SMC coverage, and optimisation identified minimum requirements to maximise malaria burden reductions. FINDINGS Model predictions show that preventing infection for the entire period between SMC cycles is more important than drug curative efficacy for clinical disease effectiveness outcomes, but similarly important for impact on prevalence. When children younger than 5 years receive four SMC cycles with high levels of coverage (ie, 69% of children receiving all cycles), drug candidates require a duration of protection half-life higher than 23 days (elimination half-life >10 days) to achieve reductions higher than 75% in clinical incidence and severe disease (measured over the intervention period in the target population, compared with no intervention across a range of modelled scenarios). High coverage is crucial to achieve these targets, requiring more than 60% of children to receive all SMC cycles and more than 90% of children to receive at least one cycle regardless of the protection duration of the drug. INTERPRETATION Although efficacy is crucial for malaria prevalence reductions, chemoprevention development should select drug candidates for their duration of protection to maximise burden reductions, with the duration half-life determining cycle timing. Explicitly designing or selecting drug properties to increase community uptake is paramount. FUNDING Bill & Melinda Gates Foundation and the Swiss National Science Foundation.
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Affiliation(s)
- Lydia Braunack-Mayer
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
| | - Josephine Malinga
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
| | - Thiery Masserey
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
| | - Narimane Nekkab
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
| | - Swapnoleena Sen
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
| | - David Schellenberg
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Sherrie L Kelly
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
| | - Melissa A Penny
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland; Telethon Kids Institute, Nedlands, WA, Australia; Centre for Child Health Research, The University of Western Australia, Perth, WA, Australia.
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3
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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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4
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Li EZ, Nguyen TD, Tran TNA, Zupko RJ, Boni MF. Assessing emergence risk of double-resistant and triple-resistant genotypes of Plasmodium falciparum. Nat Commun 2024; 15:1390. [PMID: 38360803 PMCID: PMC10869733 DOI: 10.1038/s41467-024-45547-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 01/25/2024] [Indexed: 02/17/2024] Open
Abstract
Delaying and slowing antimalarial drug resistance evolution is a priority for malaria-endemic countries. Until novel therapies become available, the mainstay of antimalarial treatment will continue to be artemisinin-based combination therapy (ACT). Deployment of different ACTs can be optimized to minimize evolutionary pressure for drug resistance by deploying them as a set of co-equal multiple first-line therapies (MFT) rather than rotating therapies in and out of use. Here, we consider one potential detriment of MFT policies, namely, that the simultaneous deployment of multiple ACTs could drive the evolution of different resistance alleles concurrently and that these resistance alleles could then be brought together by recombination into double-resistant or triple-resistant parasites. Using an individual-based model, we compare MFT and cycling policies in malaria transmission settings ranging from 0.1% to 50% prevalence. We define a total risk measure for multi-drug resistance (MDR) by summing the area under the genotype-frequency curves (AUC) of double- and triple-resistant genotypes. When prevalence ≥ 1%, total MDR risk ranges from statistically similar to 80% lower under MFT policies than under cycling policies, irrespective of whether resistance is imported or emerges de novo. At 0.1% prevalence, there is little statistical difference in MDR risk between MFT and cycling.
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Affiliation(s)
- Eric Zhewen Li
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Tran Dang Nguyen
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Thu Nguyen-Anh Tran
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Robert J Zupko
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Maciej F Boni
- Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA, USA.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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Watson DJ, Laing L, Petzer JP, Wong HN, Parkinson CJ, Wiesner L, Haynes RK. Efficacies and ADME properties of redox active methylene blue and phenoxazine analogues for use in new antimalarial triple drug combinations with amino-artemisinins. Front Pharmacol 2024; 14:1308400. [PMID: 38259296 PMCID: PMC10800708 DOI: 10.3389/fphar.2023.1308400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/11/2023] [Indexed: 01/24/2024] Open
Abstract
Efforts to develop new artemisinin triple combination therapies effective against artemisinin-tolerant strains of Plasmodium falciparum based on rational combinations comprising artemisone or other amino-artemisinins, a redox active drug and a third drug with a different mode of action have now been extended to evaluation of three potential redox partners. These are the diethyl analogue AD01 of methylene blue (MB), the benzo [α]phenoxazine PhX6, and the thiosemicarbazone DpNEt. IC50 values in vitro against CQ-sensitive and resistant P. falciparum strains ranged from 11.9 nM for AD01-41.8 nM for PhX6. PhX6 possessed the most favourable pharmacokinetic (PK) profile: intrinsic clearance rate CLint was 21.47 ± 1.76 mL/min/kg, bioavailability was 60% and half-life was 7.96 h. AD01 presented weaker, but manageable pharmacokinetic properties with a rapid CLint of 74.41 ± 6.68 mL/min/kg leading to a half-life of 2.51 ± 0.07 h and bioavailability of 15%. DpNEt exhibited a half-life of 1.12 h and bioavailability of 8%, data which discourage its further examination, despite a low CLint of 10.20 mL/min/kg and a high Cmax of 6.32 µM. Efficacies of AD01 and PhX6 were enhanced synergistically when each was paired with artemisone against asexual blood stages of P. falciparum NF54 in vitro. The favourable pharmacokinetics of PhX6 indicate this is the best partner among the compounds examined thus far for artemisone. Future work will focus on extending the drug combination studies to artemiside in vitro, and conducting efficacy studies in vivo for artemisone with each of PhX6 and the related benzo[α]phenoxazine SSJ-183.
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Affiliation(s)
- Daniel J. Watson
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Lizahn Laing
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Jacobus P. Petzer
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Ho Ning Wong
- Rural Health Research Institute, Charles Sturt University, Orange, NSW, Australia
| | | | - Lubbe Wiesner
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Richard K. Haynes
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
- Rural Health Research Institute, Charles Sturt University, Orange, NSW, Australia
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Chahine Z, Abel S, Hollin T, Chung JH, Barnes GL, Daub ME, Renard I, Choi JY, Pratap V, Pal A, Alba-Argomaniz M, Banks CAS, Kirkwood J, Saraf A, Camino I, Castaneda P, Cuevas MC, De Mercado-Arnanz J, Fernandez-Alvaro E, Garcia-Perez A, Ibarz N, Viera-Morilla S, Prudhomme J, Joyner CJ, Bei AK, Florens L, Ben Mamoun C, Vanderwal CD, Le Roch KG. A Potent Kalihinol Analogue Disrupts Apicoplast Function and Vesicular Trafficking in P. falciparum Malaria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.21.568162. [PMID: 38045341 PMCID: PMC10690269 DOI: 10.1101/2023.11.21.568162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Here we report the discovery of MED6-189, a new analogue of the kalihinol family of isocyanoterpene (ICT) natural products. MED6-189 is effective against drug-sensitive and -resistant P. falciparum strains blocking both intraerythrocytic asexual replication and sexual differentiation. This compound was also effective against P. knowlesi and P. cynomolgi. In vivo efficacy studies using a humanized mouse model of malaria confirms strong efficacy of the compound in animals with no apparent hemolytic activity or apparent toxicity. Complementary chemical biology, molecular biology, genomics and cell biological analyses revealed that MED6-189 primarily targets the parasite apicoplast and acts by inhibiting lipid biogenesis and cellular trafficking. Genetic analyses in P. falciparum revealed that a mutation in PfSec13, which encodes a component of the parasite secretory machinery, reduced susceptibility to the drug. The high potency of MED6-189 in vitro and in vivo, its broad range of efficacy, excellent therapeutic profile, and unique mode of action make it an excellent addition to the antimalarial drug pipeline.
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Affiliation(s)
- Z Chahine
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - S Abel
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - T Hollin
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - JH Chung
- Department of Chemistry, University of California, Irvine, California, 92617, USA
| | - GL Barnes
- Department of Chemistry, University of California, Irvine, California, 92617, USA
| | - ME Daub
- Department of Chemistry, University of California, Irvine, California, 92617, USA
| | - I Renard
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut, USA
| | - JY Choi
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut, USA
| | - V Pratap
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut, USA
| | - A Pal
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut, USA
| | - M Alba-Argomaniz
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Center for Vaccines and Immunology, University of Georgia, Athens, GA, United States
| | - CAS Banks
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - J Kirkwood
- Metabolomics Core Facility, University of California, Riverside, CA 92521, USA
| | - A Saraf
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - I Camino
- GSK, C/ Severo Ochoa, 2 PTM, 28760 Tres Cantos (Madrid), Spain
| | - P Castaneda
- GSK, C/ Severo Ochoa, 2 PTM, 28760 Tres Cantos (Madrid), Spain
| | - MC Cuevas
- GSK, C/ Severo Ochoa, 2 PTM, 28760 Tres Cantos (Madrid), Spain
| | | | | | - A Garcia-Perez
- GSK, C/ Severo Ochoa, 2 PTM, 28760 Tres Cantos (Madrid), Spain
| | - N Ibarz
- GSK, C/ Severo Ochoa, 2 PTM, 28760 Tres Cantos (Madrid), Spain
| | - S Viera-Morilla
- GSK, C/ Severo Ochoa, 2 PTM, 28760 Tres Cantos (Madrid), Spain
| | - J Prudhomme
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - CJ Joyner
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Center for Vaccines and Immunology, University of Georgia, Athens, GA, United States
| | - AK Bei
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - L Florens
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
| | - C Ben Mamoun
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut, USA
| | - CD Vanderwal
- Department of Chemistry, University of California, Irvine, California, 92617, USA
| | - KG Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
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Siqueira-Neto JL, Wicht KJ, Chibale K, Burrows JN, Fidock DA, Winzeler EA. Antimalarial drug discovery: progress and approaches. Nat Rev Drug Discov 2023; 22:807-826. [PMID: 37652975 PMCID: PMC10543600 DOI: 10.1038/s41573-023-00772-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2023] [Indexed: 09/02/2023]
Abstract
Recent antimalarial drug discovery has been a race to produce new medicines that overcome emerging drug resistance, whilst considering safety and improving dosing convenience. Discovery efforts have yielded a variety of new molecules, many with novel modes of action, and the most advanced are in late-stage clinical development. These discoveries have led to a deeper understanding of how antimalarial drugs act, the identification of a new generation of drug targets, and multiple structure-based chemistry initiatives. The limited pool of funding means it is vital to prioritize new drug candidates. They should exhibit high potency, a low propensity for resistance, a pharmacokinetic profile that favours infrequent dosing, low cost, preclinical results that demonstrate safety and tolerability in women and infants, and preferably the ability to block Plasmodium transmission to Anopheles mosquito vectors. In this Review, we describe the approaches that have been successful, progress in preclinical and clinical development, and existing challenges. We illustrate how antimalarial drug discovery can serve as a model for drug discovery in diseases of poverty.
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Affiliation(s)
| | - Kathryn J Wicht
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch, South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch, South Africa
| | - Kelly Chibale
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch, South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch, South Africa
| | | | - David A Fidock
- Department of Microbiology and Immunology and Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
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8
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Conrad MD, Asua V, Garg S, Giesbrecht D, Niaré K, Smith S, Namuganga JF, Katairo T, Legac J, Crudale RM, Tumwebaze PK, Nsobya SL, Cooper RA, Kamya MR, Dorsey G, Bailey JA, Rosenthal PJ. Evolution of Partial Resistance to Artemisinins in Malaria Parasites in Uganda. N Engl J Med 2023; 389:722-732. [PMID: 37611122 PMCID: PMC10513755 DOI: 10.1056/nejmoa2211803] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
BACKGROUND Partial resistance of Plasmodium falciparum to the artemisinin component of artemisinin-based combination therapies, the most important malaria drugs, emerged in Southeast Asia and now threatens East Africa. Partial resistance, which manifests as delayed clearance after therapy, is mediated principally by mutations in the kelch protein K13 (PfK13). Limited longitudinal data are available on the emergence and spread of artemisinin resistance in Africa. METHODS We performed annual surveillance among patients who presented with uncomplicated malaria at 10 to 16 sites across Uganda from 2016 through 2022. We sequenced the gene encoding kelch 13 (pfk13) and analyzed relatedness using molecular methods. We assessed malaria metrics longitudinally in eight Ugandan districts from 2014 through 2021. RESULTS By 2021-2022, the prevalence of parasites with validated or candidate resistance markers reached more than 20% in 11 of the 16 districts where surveillance was conducted. The PfK13 469Y and 675V mutations were seen in far northern Uganda in 2016-2017 and increased and spread thereafter, reaching a combined prevalence of 10 to 54% across much of northern Uganda, with spread to other regions. The 469F mutation reached a prevalence of 38 to 40% in one district in southwestern Uganda in 2021-2022. The 561H mutation, previously described in Rwanda, was first seen in southwestern Uganda in 2021, reaching a prevalence of 23% by 2022. The 441L mutation reached a prevalence of 12 to 23% in three districts in western Uganda in 2022. Genetic analysis indicated local emergence of mutant parasites independent of those in Southeast Asia. The emergence of resistance was observed predominantly in areas where effective malaria control had been discontinued or transmission was unstable. CONCLUSIONS Data from Uganda showed the emergence of partial resistance to artemisinins in multiple geographic locations, with increasing prevalence and regional spread over time. (Funded by the National Institutes of Health.).
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Affiliation(s)
- Melissa D Conrad
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Victor Asua
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Shreeya Garg
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - David Giesbrecht
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Karamoko Niaré
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Sawyer Smith
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Jane F Namuganga
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Thomas Katairo
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Jennifer Legac
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Rebecca M Crudale
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Patrick K Tumwebaze
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Samuel L Nsobya
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Roland A Cooper
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Moses R Kamya
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Grant Dorsey
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Jeffrey A Bailey
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
| | - Philip J Rosenthal
- From the University of California, San Francisco, San Francisco (M.D.C., S.G., J.L., G.D., P.J.R.); the Infectious Diseases Research Collaboration (V.A., J.F.N., T.K., P.K.T., S.L.N., M.R.K.) and Makerere University (M.R.K.) - both in Kampala, Uganda; the University of Tübingen, Tübingen, Germany (V.A.); Brown University, Providence, RI (D.G., K.N., S.S., R.M.C., J.A.B.); and Dominican University of California, San Rafael (R.A.C.)
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9
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Tadele G, Jawara A, Oboh M, Oriero E, Dugassa S, Amambua-Ngwa A, Golassa L. Clinical isolates of uncomplicated falciparum malaria from high and low malaria transmission areas show distinct pfcrt and pfmdr1 polymorphisms in western Ethiopia. Malar J 2023; 22:171. [PMID: 37270589 DOI: 10.1186/s12936-023-04602-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 05/20/2023] [Indexed: 06/05/2023] Open
Abstract
BACKGROUND Pfcrt gene has been associated with chloroquine resistance and the pfmdr1 gene can alter malaria parasite susceptibility to lumefantrine, mefloquine, and chloroquine. In the absence of chloroquine (CQ) and extensive use of artemether-lumefantrine (AL) from 2004 to 2020 to treat uncomplicated falciparum malaria, pfcrt haplotype, and pfmdr1 single nucleotide polymorphisms (SNPs) were determined in two sites of West Ethiopia with a gradient of malaria transmission. METHODS 230 microscopically confirmed P. falciparum isolates were collected from Assosa (high transmission area) and Gida Ayana (low transmission area) sites, of which 225 of them tested positive by PCR. High-Resolution Melting Assay (HRM) was used to determine the prevalence of pfcrt haplotypes and pfmdr1 SNPs. Furthermore, the pfmdr1 gene copy number (CNV) was determined using real-time PCR. A P-value of less or equal to 0.05 was considered significant. RESULTS Of the 225 samples, 95.5%, 94.4%, 86.7%, 91.1%, and 94.2% were successfully genotyped with HRM for pfcrt haplotype, pfmdr1-86, pfmdr1-184, pfmdr1-1042 and pfmdr1-1246, respectively. The mutant pfcrt haplotypes were detected among 33.5% (52/155) and 80% (48/60) of isolates collected from the Assosa and Gida Ayana sites, respectively. Plasmodium falciparum with chloroquine-resistant haplotypes was more prevalent in the Gida Ayana area compared with the Assosa area (COR = 8.4, P = 0.00). Pfmdr1-N86Y wild type and 184F mutations were found in 79.8% (166/208) and 73.4% (146/199) samples, respectively. No single mutation was observed at the pfmdr1-1042 locus; however, 89.6% (190/212) of parasites in West Ethiopia carry the wild-type D1246Y variants. Eight pfmdr1 haplotypes at codons N86Y-Y184F-D1246Y were identified with the dominant NFD 61% (122/200). There was no difference in the distribution of pfmdr1 SNPs, haplotypes, and CNV between the two study sites (P > 0.05). CONCLUSION Plasmodium falciparum with the pfcrt wild-type haplotype was prevalent in high malaria transmission site than in low transmission area. The NFD haplotype was the predominant haplotype of the N86Y-Y184F-D1246Y. A continuous investigation is needed to closely monitor the changes in the pfmdr1 SNPs, which are associated with the selection of parasite populations by ACT.
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Affiliation(s)
- Geletta Tadele
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Aminata Jawara
- Medical Research Council Unit the Gambia, London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Mary Oboh
- Medical Research Council Unit the Gambia, London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Eniyou Oriero
- Medical Research Council Unit the Gambia, London School of Hygiene and Tropical Medicine, Banjul, 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, Banjul, Gambia
| | - Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
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10
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Ehrlich HY, Somé AF, Bazié T, Ebou CN, Dembélé EL, Balma R, Goodwin J, Wade M, Bei AK, Ouédraogo JB, Foy BD, Dabiré RK, Parikh S. Tracking antimalarial drug resistance using mosquito blood meals: a cross-sectional study. THE LANCET. MICROBE 2023; 4:e461-e469. [PMID: 37086737 PMCID: PMC10365133 DOI: 10.1016/s2666-5247(23)00063-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 04/24/2023]
Abstract
BACKGROUND Strong surveillance systems with wide geographic coverage are needed to detect and respond to reports of antimalarial drug resistance on the African continent. We aimed to assess the utility and feasibility of using blood-fed mosquitos (xenomonitoring) to conduct rapid surveillance of molecular markers associated with resistance in human populations. METHODS We conducted three cross-sectional surveys in two rainy seasons and the interim dry season in southwest Burkina Faso between Oct 10, 2018, and Sept 17, 2019. We collected human blood samples and blood-fed mosquitos residing in household clusters across seven village sectors. Samples were assessed for Plasmodium falciparum with ultrasensitive quantitative PCR, genotyped for two markers of reduced drug susceptibility, pfmdr1 256A>T (Asn86Tyr) and pfcrt 227A>C (Lys76Thr), and sequenced for four markers of clonality. We assessed statistical equivalence using a 10% margin of equivalence. FINDINGS We identified 551 infections in 1483 human blood samples (mean multiplicity of infection [MOI] 1·94, SD 1·47) and 346 infections in 2151 mosquito blood meals (mean MOI 2·2, SD 1·67). The frequency of pfmdr1 Asn86Tyr was 4% in survey 1, 2% in survey 2, and 12% in survey 3 in human samples, and 3% in survey 1, 0% in survey 2, and 8% in survey 3 in mosquito blood meals, and inter-host frequencies were statistically equivalent in surveys 1 and 2 (p<0·0001) but not Survey 3 (p=0·062) within a tolerability of 0·10. The frequency of pfcrt Lys76Thr was 16% in survey 1, 55% in survey 2, and 11% in survey 3 in humans and 40% in survey 1, 72% in survey 2, and 13% in survey 3 in mosquitos, and inter-host frequencies were equivalent in survey 3 only (p=0·032) within a tolerability of 0·10. In simulations, multiple but not preferential feeding behaviour in mosquitos reduced the accuracy of frequency estimates between hosts, particularly for markers circulating at higher frequencies. INTERPRETATION Molecular markers in mosquito blood meals and in humans exhibited similar temporal trends but frequencies were not statistically equivalent in all scenarios. More work is needed to determine empirical and pragmatic thresholds of difference. Xenomonitoring might be an efficient tool to provide rapid information on emerging antimalarial resistance in regions with insufficient surveillance. FUNDING National Institute of Allergy and Infectious Diseases. TRANSLATION For the French translation of the abstract see Supplementary Materials section.
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Affiliation(s)
- Hanna Y Ehrlich
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA; One Health Institute, University of California, Davis, CA, USA.
| | - A Fabrice Somé
- Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Thomas Bazié
- Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Cathérine Neya Ebou
- Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Estelle Lotio Dembélé
- Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Richard Balma
- Department of Medical Entomology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Justin Goodwin
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA
| | - Martina Wade
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA
| | - Amy K Bei
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA
| | - Jean-Bosco Ouédraogo
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA; Department of Parasitology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Brian D Foy
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Roch K Dabiré
- Department of Medical Entomology, Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | - Sunil Parikh
- Department of Epidemiology of Microbial Diseases, Yale University, New Haven, CT, USA
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11
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Whalen ME, Kajubi R, Goodwin J, Orukan F, Colt M, Huang L, Richards K, Wang K, Li F, Mwebaza N, Aweeka FT, Parikh S. The Impact of Extended Treatment With Artemether-lumefantrine on Antimalarial Exposure and Reinfection Risks in Ugandan Children With Uncomplicated Malaria: A Randomized Controlled Trial. Clin Infect Dis 2023; 76:443-452. [PMID: 36130191 PMCID: PMC9907485 DOI: 10.1093/cid/ciac783] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/12/2022] [Accepted: 09/19/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Artemether-lumefantrine (AL) is the most widely used artemisinin-based combination therapy in Sub-Saharan Africa and is threatened by the emergence of artemisinin resistance. Dosing is suboptimal in young children. We hypothesized that extending AL duration will improve exposure and reduce reinfection risks. METHODS We conducted a prospective, randomized, open-label pharmacokinetic/pharmacodynamic study of extended duration AL in children with malaria in high-transmission rural Uganda. Children received 3-day (standard 6-dose) or 5-day (10-dose) AL with sampling for artemether, dihydroartemisinin, and lumefantrine over 42-day clinical follow-up. Primary outcomes were (1) comparative pharmacokinetic parameters between regimens and (2) recurrent parasitemia analyzed as intention-to-treat. RESULTS A total of 177 children aged 16 months to 16 years were randomized, contributing 227 total episodes. Terminal median lumefantrine concentrations were significantly increased in the 5-day versus 3-day regimen on days 7, 14, and 21 (P < .001). A predefined day 7 lumefantrine threshold of 280 ng/mL was strongly predictive of recurrence risk at 28 and 42 days (P < .001). Kaplan-Meier estimated 28-day (51% vs 40%) and 42-day risk (75% vs 68%) did not significantly differ between 3- and 5-day regimens. No significant toxicity was seen with the extended regimen. CONCLUSIONS Extending the duration of AL was safe and significantly enhanced overall drug exposure in young children but did not lead to significant reductions in recurrent parasitemia risk in our high-transmission setting. However, day 7 levels were strongly predictive of recurrent parasitemia risk, and those in the lowest weight-band were at higher risk of underdosing with the standard 3-day regimen. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov number NCT03453840.
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Affiliation(s)
- Meghan E Whalen
- Department of Clinical Pharmacy, University of California-San Francisco, San Francisco General Hospital, San Francisco, California, USA
| | - Richard Kajubi
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Justin Goodwin
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - Francis Orukan
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - McKenzie Colt
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - Liusheng Huang
- Department of Clinical Pharmacy, University of California-San Francisco, San Francisco General Hospital, San Francisco, California, USA
| | - Kacey Richards
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - Kaicheng Wang
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - Fangyong Li
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - Norah Mwebaza
- Infectious Disease Research Collaboration, Kampala, Uganda.,Department of Pharmacology and Therapeutics, Makerere University College of Health Sciences, Kampala, Uganda
| | - Francesca T Aweeka
- Department of Clinical Pharmacy, University of California-San Francisco, San Francisco General Hospital, San Francisco, California, USA
| | - Sunil Parikh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
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