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Fornace KM, Zorello Laporta G, Vythilingham I, Chua TH, Ahmed K, Jeyaprakasam NK, de Castro Duarte AMR, Amir A, Phang WK, Drakeley C, Sallum MAM, Lau YL. Simian malaria: a narrative review on emergence, epidemiology and threat to global malaria elimination. THE LANCET. INFECTIOUS DISEASES 2023; 23:e520-e532. [PMID: 37454671 DOI: 10.1016/s1473-3099(23)00298-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/19/2023] [Accepted: 04/28/2023] [Indexed: 07/18/2023]
Abstract
Simian malaria from wild non-human primate populations is increasingly recognised as a public health threat and is now the main cause of human malaria in Malaysia and some regions of Brazil. In 2022, Malaysia became the first country not to achieve malaria elimination due to zoonotic simian malaria. We review the global distribution and drivers of simian malaria and identify priorities for diagnosis, treatment, surveillance, and control. Environmental change is driving closer interactions between humans and wildlife, with malaria parasites from non-human primates spilling over into human populations and human malaria parasites spilling back into wild non-human primate populations. These complex transmission cycles require new molecular and epidemiological approaches to track parasite spread. Current methods of malaria control are ineffective, with wildlife reservoirs and primarily outdoor-biting mosquito vectors urgently requiring the development of novel control strategies. Without these, simian malaria has the potential to undermine malaria elimination globally.
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Affiliation(s)
- Kimberly M Fornace
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK; Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore, Singapore; Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Gabriel Zorello Laporta
- Graduate Research and Innovation Program, Centro Universitario FMABC, Santo André, São Paulo, Brazil
| | | | | | - Kamruddin Ahmed
- Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia; Borneo Medical and Health Research Centre, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Nantha K Jeyaprakasam
- Biomedical Science Programme, Center for Toxicology and Health Risk Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Ana Maria Ribeiro de Castro Duarte
- Laboratory of Protozoology, Institute of Tropical Medicine of São Paulo, Universidade de São Paulo, São Paulo, Brazil; Instituto Pasteur, Secretaria de Estado da Saude de São Paulo, São Paulo, Brazil
| | - Amirah Amir
- Department of Parasitology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Wei Kit Phang
- Department of Parasitology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Maria Anice M Sallum
- Departamento de Epidemiologia, Faculdade de Saude Publica, Universidade de São Paulo, São Paulo, Brazil
| | - Yee Ling Lau
- Department of Parasitology, Universiti Malaya, Kuala Lumpur, Malaysia
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T. Thurai Rathnam J, Grigg MJ, Dini S, William T, Sakam SS, Cooper DJ, Rajahram GS, Barber BE, Anstey NM, Haghiri A, Rajasekhar M, Simpson JA. Quantification of parasite clearance in Plasmodium knowlesi infections. Malar J 2023; 22:54. [PMID: 36782162 PMCID: PMC9926767 DOI: 10.1186/s12936-023-04483-9] [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: 11/30/2022] [Accepted: 02/04/2023] [Indexed: 02/15/2023] Open
Abstract
BACKGROUND The incidence of zoonotic Plasmodium knowlesi infections in humans is rising in Southeast Asia, leading to clinical studies to monitor the efficacy of anti-malarial treatments for knowlesi malaria. One of the key outcomes of anti-malarial drug efficacy is parasite clearance. For Plasmodium falciparum, parasite clearance is typically estimated using a two-stage method, that involves estimating parasite clearance for individual patients followed by pooling of individual estimates to derive population estimates. An alternative approach is Bayesian hierarchical modelling which simultaneously analyses all parasite-time patient profiles to determine parasite clearance. This study compared these methods for estimating parasite clearance in P. knowlesi treatment efficacy studies, with typically fewer parasite measurements per patient due to high susceptibility to anti-malarials. METHODS Using parasite clearance data from 714 patients with knowlesi malaria and enrolled in three trials, the Worldwide Antimalarial Resistance Network (WWARN) Parasite Clearance Estimator (PCE) standard two-stage approach and Bayesian hierarchical modelling were compared. Both methods estimate the parasite clearance rate from a model that incorporates a lag phase, slope, and tail phase for the parasitaemia profiles. RESULTS The standard two-stage approach successfully estimated the parasite clearance rate for 678 patients, with 36 (5%) patients excluded due to an insufficient number of available parasitaemia measurements. The Bayesian hierarchical estimation method was applied to the parasitaemia data of all 714 patients. Overall, the Bayesian method estimated a faster population mean parasite clearance (0.36/h, 95% credible interval [0.18, 0.65]) compared to the standard two-stage method (0.26/h, 95% confidence interval [0.11, 0.46]), with better model fits (compared visually). Artemisinin-based combination therapy (ACT) is more effective in treating P. knowlesi than chloroquine, as confirmed by both methods, with a mean estimated parasite clearance half-life of 2.5 and 3.6 h, respectively using the standard two-stage method, and 1.8 and 2.9 h using the Bayesian method. CONCLUSION For clinical studies of P. knowlesi with frequent parasite measurements, the standard two-stage approach (WWARN's PCE) is recommended as this method is straightforward to implement. For studies with fewer parasite measurements per patient, the Bayesian approach should be considered. Regardless of method used, ACT is more efficacious than chloroquine, confirming the findings of the original trials.
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Affiliation(s)
- Jeyamalar T. Thurai Rathnam
- grid.1008.90000 0001 2179 088XCentre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Matthew J. Grigg
- grid.1043.60000 0001 2157 559XMenzies School of Health Research and Charles Darwin University, Darwin, NT Australia ,Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Saber Dini
- grid.1008.90000 0001 2179 088XCentre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Timothy William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Sitti Saimah Sakam
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Daniel J. Cooper
- grid.1043.60000 0001 2157 559XMenzies School of Health Research and Charles Darwin University, Darwin, NT Australia ,Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia ,grid.5335.00000000121885934Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Giri S. Rajahram
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia ,grid.415759.b0000 0001 0690 5255Clinical Research Centre, Queen Elizabeth II Hospital, Ministry of Health, Kota Kinabalu, Sabah, Malaysia
| | - Bridget E. Barber
- grid.1043.60000 0001 2157 559XMenzies School of Health Research and Charles Darwin University, Darwin, NT Australia ,Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia ,grid.1049.c0000 0001 2294 1395QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Nicholas M. Anstey
- grid.1043.60000 0001 2157 559XMenzies School of Health Research and Charles Darwin University, Darwin, NT Australia ,Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Ali Haghiri
- grid.1008.90000 0001 2179 088XCentre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Megha Rajasekhar
- grid.1008.90000 0001 2179 088XCentre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Julie A. Simpson
- grid.1008.90000 0001 2179 088XCentre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
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Lee WC, Cheong FW, Amir A, Lai MY, Tan JH, Phang WK, Shahari S, Lau YL. Plasmodium knowlesi: the game changer for malaria eradication. Malar J 2022; 21:140. [PMID: 35505339 PMCID: PMC9066973 DOI: 10.1186/s12936-022-04131-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/18/2022] [Indexed: 11/12/2022] Open
Abstract
Plasmodium knowlesi is a zoonotic malaria parasite that has gained increasing medical interest over the past two decades. This zoonotic parasitic infection is prevalent in Southeast Asia and causes many cases with fulminant pathology. Despite several biogeographical restrictions that limit its distribution, knowlesi malaria cases have been reported in different parts of the world due to travelling and tourism activities. Here, breakthroughs and key information generated from recent (over the past five years, but not limited to) studies conducted on P. knowlesi were reviewed, and the knowledge gap in various research aspects that need to be filled was discussed. Besides, challenges and strategies required to control and eradicate human malaria with this emerging and potentially fatal zoonosis were described.
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Affiliation(s)
- Wenn-Chyau Lee
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Fei Wen Cheong
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Amirah Amir
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Meng Yee Lai
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jia Hui Tan
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Wei Kit Phang
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Shahhaziq Shahari
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
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Ruiz Cuenca P, Key S, Lindblade KA, Vythilingam I, Drakeley C, Fornace K. Is there evidence of sustained human-mosquito-human transmission of the zoonotic malaria Plasmodium knowlesi? A systematic literature review. Malar J 2022; 21:89. [PMID: 35300703 PMCID: PMC8929260 DOI: 10.1186/s12936-022-04110-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/27/2022] [Indexed: 12/03/2022] Open
Abstract
Background The zoonotic malaria parasite Plasmodium knowlesi has emerged across Southeast Asia and is now the main cause of malaria in humans in Malaysia. A critical priority for P. knowlesi surveillance and control is understanding whether transmission is entirely zoonotic or is also occurring through human-mosquito-human transmission. Methods A systematic literature review was performed to evaluate existing evidence which refutes or supports the occurrence of sustained human-mosquito-human transmission of P. knowlesi. Possible evidence categories and study types which would support or refute non-zoonotic transmission were identified and ranked. A literature search was conducted on Medline, EMBASE and Web of Science using a broad search strategy to identify any possible published literature. Results were synthesized using the Synthesis Without Meta-analysis (SWiM) framework, using vote counting to combine the evidence within specific categories. Results Of an initial 7,299 studies screened, 131 studies were included within this review: 87 studies of P. knowlesi prevalence in humans, 14 studies in non-human primates, 13 studies in mosquitoes, and 29 studies with direct evidence refuting or supporting non-zoonotic transmission. Overall, the evidence showed that human-mosquito-human transmission is biologically possible, but there is limited evidence of widespread occurrence in endemic areas. Specific areas of research were identified that require further attention, notably quantitative analyses of potential transmission dynamics, epidemiological and entomological surveys, and ecological studies into the sylvatic cycle of the disease. Conclusion There are key questions about P. knowlesi that remain within the areas of research that require more attention. These questions have significant implications for malaria elimination and eradication programs. This paper considers limited but varied research and provides a methodological framework for assessing the likelihood of different transmission patterns for emerging zoonotic diseases. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04110-z.
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Affiliation(s)
- Pablo Ruiz Cuenca
- Centre for Health Informatics, Computing, and Statistics (CHICAS), Lancaster University Medical School, Lancaster, UK. .,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | - Stephanie Key
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Kim A Lindblade
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Kimberly Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
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Genetic population of Plasmodium knowlesi during pre-malaria elimination in Thailand. Malar J 2021; 20:454. [PMID: 34861860 PMCID: PMC8641246 DOI: 10.1186/s12936-021-03990-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 11/18/2021] [Indexed: 11/24/2022] Open
Abstract
Background Thailand is committed to eliminating malaria by 2024. From 2013 to 2020, the total number of malaria cases have decreased, from 37,741 to 4474 (an 88.1% reduction). However, infections with Plasmodium knowlesi, a monkey malarial pathogen that can also infect humans, have been increasingly observed. This study focused on the molecular analysis of P. knowlesi parasites causing malaria in Thailand. Methods Under Thailand’s integrated Drug Efficacy Surveillance (iDES), which includes drug-resistance monitoring as part of routine case-based surveillance and responses, specimens were collected from malaria patients (n = 966) between 2018 and 2020. Thirty-one mono P. knowlesi infections (3.1%), most of which were from eastern and southern Thailand, were observed and confirmed by nested PCR assay and DNA sequencing. To evaluate whether these pathogens were from different lineages, cluster analysis based on seven microsatellite genotyping markers and the merozoite surface protein 1 (pkmsp1) gene was carried out. The P. knowlesi pyrimethamine resistance gene dihydrofolate reductase (pkdhfr) was sequenced and homology modelling was constructed. Results The results of analysing the seven microsatellite markers and pkmsp1 sequence demonstrated that P. knowlesi parasites from eastern Thailand were of the same lineage as those isolated in Cambodia, while the parasites causing malaria in southern Thailand were the same lineage as those isolated from Malaysia. The sequencing results for the pkdhfr genes indicated the presence of two mutations, Arg34Leu and a deletion at position 105. On analysis with homology modelling, the two mutations were not associated with anti-malarial drug resistance. Conclusions This report compared the genetic populations of P. knowlesi parasites in Thailand from 2018 to 2020 and have shown similar lineages as those isolated in Cambodia and Malaysia of P. knowlesi infection in Thailand and demonstrated that the P. knowlesi parasites were of the same lineages as those isolated in Cambodia and Malaysia. The parasites were also shown to be sensitive to pyrimethamine.
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Barber BE, Grigg MJ, Cooper DJ, van Schalkwyk DA, William T, Rajahram GS, Anstey NM. Clinical management of Plasmodium knowlesi malaria. ADVANCES IN PARASITOLOGY 2021; 113:45-76. [PMID: 34620385 DOI: 10.1016/bs.apar.2021.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The zoonotic parasite Plasmodium knowlesi has emerged as an important cause of human malaria in parts of Southeast Asia. The parasite is indistinguishable by microscopy from the more benign P. malariae, but can result in high parasitaemias with multiorgan failure, and deaths have been reported. Recognition of severe knowlesi malaria, and prompt initiation of effective therapy is therefore essential to prevent adverse outcomes. Here we review all studies reporting treatment of uncomplicated and severe knowlesi malaria. We report that although chloroquine is effective for the treatment of uncomplicated knowlesi malaria, artemisinin combination treatment is associated with faster parasite clearance times and lower rates of anaemia during follow-up, and should be considered the treatment of choice, particularly given the risk of administering chloroquine to drug-resistant P. vivax or P. falciparum misdiagnosed as P. knowlesi malaria in co-endemic areas. For severe knowlesi malaria, intravenous artesunate has been shown to be highly effective and associated with reduced case-fatality rates, and should be commenced without delay. Regular paracetamol may also be considered for patients with severe knowlesi malaria or for those with acute kidney injury, to attenuate the renal damage resulting from haemolysis-induced lipid peroxidation.
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Affiliation(s)
- Bridget E Barber
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia.
| | - Matthew J Grigg
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Daniel J Cooper
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Department of Medicine, University of Cambridge School of Medicine, Cambridge, United Kingdom
| | | | - Timothy William
- Gleneagles Medical Centre, Kota Kinabalu, Malaysia; Clinical Research Centre, Queen Elizabeth Hospital 1, Kota Kinabalu, Malaysia
| | - Giri S Rajahram
- Clinical Research Centre, Queen Elizabeth Hospital 1, Kota Kinabalu, Malaysia; Queen Elizabeth Hospital 2, Kota Kinabalu, Malaysia
| | - Nicholas M Anstey
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
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Knowlesi malaria: Human risk factors, clinical spectrum, and pathophysiology. ADVANCES IN PARASITOLOGY 2021; 113:1-43. [PMID: 34620381 DOI: 10.1016/bs.apar.2021.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Plasmodium knowlesi is endemic across Southeast Asia, and is the commonest cause of zoonotic malaria. The spectrum of clinical disease from P. knowlesi infection ranges from asymptomatic infection, through to severe malaria and death. Over 90% of clinical disease occurs in adults, mostly living in forest edge areas undergoing intensive land use change. With a 24-h asexual life cycle in humans, high parasite counts are possible, but most clinical cases of knowlesi malaria are uncomplicated with low parasitaemia. In co-endemic areas, median parasitaemia in knowlesi malaria is lower than that seen in vivax and falciparum malaria, suggesting a lower fever threshold. Severe malaria occurs in 6-9% of symptomatic adults. Manifestations of severe malaria from P. knowlesi are similar to those seen with falciparum malaria, with the notable absence of coma. Age, parasitaemia, cardiovascular comorbidities and delayed diagnosis are risk factors for severe disease and death, which are only seen in adults. Thrombocytopenia is near-universal in adults, likely related to platelet-red cell binding and clearance. Mechanisms underlying the microvascular sludging seen in fatal disease in non-natural primate hosts and the microvascular accumulation of parasites in fatal human disease are not clear. Marked reductions in deformability of both infected and uninfected red blood cells are associated with disease severity in both humans and other non-natural primate hosts, likely contributing to impaired microvascular perfusion and organ dysfunction. Endothelial activation, endothelial dysfunction, glycocalyx degradation and haemolysis are also associated with, and likely contribute to, severe disease and organ dysfunction, particularly acute kidney injury.
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Grigg MJ, Lubis IN, Tetteh KKA, Barber BE, William T, Rajahram GS, Tan AF, Sutherland CJ, Noviyanti R, Drakeley CJ, Britton S, Anstey NM. Plasmodium knowlesi detection methods for human infections-Diagnosis and surveillance. ADVANCES IN PARASITOLOGY 2021; 113:77-130. [PMID: 34620386 DOI: 10.1016/bs.apar.2021.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Within the overlapping geographical ranges of P. knowlesi monkey hosts and vectors in Southeast Asia, an estimated 1.5 billion people are considered at risk of infection. P. knowlesi can cause severe disease and death, the latter associated with delayed treatment occurring from misdiagnosis. Although microscopy is a sufficiently sensitive first-line tool for P. knowlesi detection for most low-level symptomatic infections, misdiagnosis as other Plasmodium species is common, and the majority of asymptomatic infections remain undetected. Current point-of-care rapid diagnostic tests demonstrate insufficient sensitivity and poor specificity for differentiating P. knowlesi from other Plasmodium species. Molecular tools including nested, real-time, and single-step PCR, and loop-mediated isothermal amplification (LAMP), are sensitive for P. knowlesi detection. However, higher cost and inability to provide the timely point-of-care diagnosis needed to guide appropriate clinical management has limited their routine use in most endemic clinical settings. P. knowlesi is likely underdiagnosed across the region, and improved diagnostic and surveillance tools are required. Reference laboratory molecular testing of malaria cases for both zoonotic and non-zoonotic Plasmodium species needs to be more widely implemented by National Malaria Control Programs across Southeast Asia to accurately identify the burden of zoonotic malaria and more precisely monitor the success of human-only malaria elimination programs. The implementation of specific serological tools for P. knowlesi would assist in determining the prevalence and distribution of asymptomatic and submicroscopic infections, the absence of transmission in certain areas, and associations with underlying land use change for future spatially targeted interventions.
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Affiliation(s)
- Matthew J Grigg
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia.
| | - Inke N Lubis
- Faculty of Medicine, Universitas Sumatera Utara, Medan, Sumatera Utara, Indonesia
| | - Kevin K A Tetteh
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Bridget E Barber
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia; QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Timothy William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia; Clinical Research Centre, Queen Elizabeth Hospital 1, Kota Kinabalu, Malaysia; Gleneagles Medical Centre, Kota Kinabalu, Malaysia
| | - Giri S Rajahram
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia; Clinical Research Centre, Queen Elizabeth Hospital 1, Kota Kinabalu, Malaysia; Queen Elizabeth Hospital 2, Kota Kinabalu, Malaysia
| | - Angelica F Tan
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Colin J Sutherland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Chris J Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sumudu Britton
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Nicholas M Anstey
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia; Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
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Yadav MK, Tripathi MK, Yadav S. Discovery of novel inhibitors targeting Plasmodium knowlesi dihydrofolate reductase using molecular docking and molecular dynamics simulation. Microb Pathog 2021; 161:105214. [PMID: 34592368 DOI: 10.1016/j.micpath.2021.105214] [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: 02/10/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 10/20/2022]
Abstract
Plasmodium knowlesi, recognized as the fifth Plasmodium parasite, is the least studied malaria parasite. It is a significant cause of morbidity and mortality in the South-East Asia region. Enzymes of folate synthesis, especially dihydrofolate reductase (DHFR), is a well-approved drug target in other Plasmodium species, but its role in Plasmodium knowlesi is poorly studied. This work characterizes PkDHFR as a drug target and identifies inhibitors that can withstand the upcoming problem of resistance. The 3D structure of the PkDHFR target is modelled using comparative modelling, and further, it is refined and validated using energy minimization and torsional angle analysis methods. We extracted 13 compounds from DrugBank and ZINC databases using the "target similarity search" criteria. These compounds were categorized based on their binding affinity (-4.49 to -10.08 kcal/mol) and pose prediction against the active site of PkDHFR. Later on, the top 5 PkDHFR-compound complexes with high or equivalent binding affinity to its natural ligand (dihydrofolate) have undergone for dynamics. The simulation experiments reveal the higher stability of DB00563-PkDHFR complex and less conformational fluctuations and share a similar degree of compactness throughout the simulation trajectory. The MM/GBSA calculation of free energy of DB00563 is also the least (-72.84 kcal/mol) compared to others. Furthermore, the flexible side chain of DB00563 can bind and block the active site of PkDHFR more efficiently. Thus, the identified drug may be considered as a potential candidate for treating P. knowlesi malaria.
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Affiliation(s)
- Manoj Kumar Yadav
- Department of Bioinformatics, SRM University, Delhi-NCR, Rajiv Gandhi Education City, Sonepat, 131 029, Haryana, India.
| | - Manish Kumar Tripathi
- Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University, Varanasi, 221 005, Uttar Pradesh, India
| | - Srishti Yadav
- Medical Biotechnology Division, Department of Biochemistry, Pt. Jawaharlal Nehru Memorial Medical College, Raipur, 492 001, Chhattisgarh, India
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Imwong M, Madmanee W, Suwannasin K, Kunasol C, Peto TJ, Tripura R, von Seidlein L, Nguon C, Davoeung C, Day NPJ, Dondorp AM, White NJ. Asymptomatic Natural Human Infections With the Simian Malaria Parasites Plasmodium cynomolgi and Plasmodium knowlesi. J Infect Dis 2019; 219:695-702. [PMID: 30295822 PMCID: PMC6376906 DOI: 10.1093/infdis/jiy519] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In Southeast Asia, Plasmodium knowlesi, a parasite of long-tailed macaques (Macaca fascicularis), is an important cause of human malaria. Plasmodium cynomolgi also commonly infects these monkeys, but only one naturally acquired symptomatic human case has been reported previously. METHODS Malariometric studies involving 5422 subjects (aged 6 months to 65 years) were conducted in 23 villages in Pailin and Battambang, western Cambodia. Parasite detection and genotyping was conducted on blood samples, using high-volume quantitative PCR (uPCR). RESULTS Asymptomatic malaria parasite infections were detected in 1361 of 14732 samples (9.2%). Asymptomatic infections with nonhuman primate malaria parasites were found in 21 individuals living close to forested areas; P. cynomolgi was found in 11, P. knowlesi was found in 8, and P. vivax and P. cynomolgi were both found in 2. Only 2 subjects were female, and 14 were men aged 20-40 years. Geometric mean parasite densities were 3604 parasites/mL in P. cynomolgi infections and 52488 parasites/mL in P. knowlesi infections. All P. cynomolgi isolates had wild-type dihydrofolate reductase genes, in contrast to the very high prevalence of mutations in the human malaria parasites. Asymptomatic reappearance of P. cynomolgi occurred in 2 subjects 3 months after the first infection. CONCLUSIONS Asymptomatic naturally acquired P. cynomolgi and P. knowlesi infections can both occur in humans. CLINICAL TRIALS REGISTRATION NCT01872702.
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Affiliation(s)
- Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Mahidol University, Bangkok, Thailand.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wanassanan Madmanee
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kanokon Suwannasin
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chanon Kunasol
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thomas J Peto
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Rupam Tripura
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Lorenz von Seidlein
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Chea Nguon
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh
| | | | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
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11
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Ittarat W, Pornthanakasem W, Mungthin M, Suwandittakul N, Leelayoova S, Tarnchompoo B, Yuthavong Y, Kongkasuriyachai D, Leartsakulpanich U. Characterization of Plasmodium knowlesi dihydrofolate reductase-thymidylate synthase and sensitivity to antifolates. Parasitol Int 2018; 67:787-792. [PMID: 30114522 DOI: 10.1016/j.parint.2018.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 08/03/2018] [Accepted: 08/13/2018] [Indexed: 12/28/2022]
Abstract
Malaria caused by an infection of Plasmodium knowlesi can result in high parasitemia and deaths. Therefore, effective and prompt treatment is necessary to reduce morbidity and mortality. The study aims to characterize P. knowlesi dihydrofolate reductase-thymidylate synthase enzyme (PkDHFR-TS) and its sensitivity to antifolates. The putative Pkdhfr gene was PCR amplified from field isolates collected from the Southern Thailand. Molecular analysis showed 11 polymorphisms in the dhfr domain of the bifunctional dhfr-ts gene. Of these, 1 polymorphism was a non-synonymous substitution (R34L) that had previously been reported but not associated with antifolate resistance. The recombinant PkDHFR-TS enzyme was found to be sensitive to standard antifolates-pyrimethamine and cycloguanil-as well as P218, a registered candidate drug currently first in human clinical trial. Results suggest that antifolates class of compounds should be effective against P. knowlesi infection.
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Affiliation(s)
- Wanwipa Ittarat
- National Center for Genetic Engineering and Biotechnology, 113 Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Wichai Pornthanakasem
- National Center for Genetic Engineering and Biotechnology, 113 Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Mathirut Mungthin
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok 10400, Thailand
| | - Nantana Suwandittakul
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok 10400, Thailand
| | - Saovanee Leelayoova
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok 10400, Thailand
| | - Bongkoch Tarnchompoo
- National Center for Genetic Engineering and Biotechnology, 113 Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Yongyuth Yuthavong
- National Center for Genetic Engineering and Biotechnology, 113 Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Darin Kongkasuriyachai
- National Center for Genetic Engineering and Biotechnology, 113 Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Ubolsree Leartsakulpanich
- National Center for Genetic Engineering and Biotechnology, 113 Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand.
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12
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Amir A, Cheong FW, de Silva JR, Liew JWK, Lau YL. Plasmodium knowlesi malaria: current research perspectives. Infect Drug Resist 2018; 11:1145-1155. [PMID: 30127631 PMCID: PMC6089103 DOI: 10.2147/idr.s148664] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Originally known to cause simian malaria, Plasmodium knowlesi is now known as the fifth human malaria species. Since the publishing of a report that largely focused on human knowlesi cases in Sarawak in 2004, many more human cases have been reported in nearly all of the countries in Southeast Asia and in travelers returning from these countries. The zoonotic nature of this infection hinders malaria elimination efforts. In order to grasp the current perspective of knowlesi malaria, this literature review explores the different aspects of the disease including risk factors, diagnosis, treatment, and molecular and functional studies. Current studies do not provide sufficient data for an effective control program. Therefore, future direction for knowlesi research is highlighted here with a final aim of controlling, if not eliminating, the parasite.
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Affiliation(s)
- Amirah Amir
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
| | - Fei Wen Cheong
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
| | - Jeremy Ryan de Silva
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
| | - Jonathan Wee Kent Liew
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
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13
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Abstract
Plasmodium knowlesi is a simian malaria of primarily the macaque species of South East Asia. While it was known that human infections could be induced during the years of malariotherapy, naturally occurring P. knowlesi human infections were thought to be rare. However, in 2004, knowlesi infections became recognized as an important infection amongst human populations in Sarawak, Malaysian Borneo. Since then, it has become recognized as a disease affecting people living and visiting endemic areas across South East Asia. Over the last 12 years, clinical studies have improved our understanding of this potentially fatal disease. In this review article the current literature is reviewed to give a comprehensive description of the disease and treatment.
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14
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Barber BE, Grigg MJ, William T, Yeo TW, Anstey NM. The Treatment of Plasmodium knowlesi Malaria. Trends Parasitol 2016; 33:242-253. [PMID: 27707609 DOI: 10.1016/j.pt.2016.09.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/31/2016] [Accepted: 09/07/2016] [Indexed: 12/30/2022]
Abstract
Plasmodium knowlesi occurs across Southeast Asia and is the most common cause of malaria in Malaysia. High parasitaemias can develop rapidly, and the risk of severe disease in adults is at least as high as in falciparum malaria. Prompt initiation of effective treatment is therefore essential. Intravenous artesunate is highly effective in severe knowlesi malaria and in those with moderately high parasitaemia but otherwise uncomplicated disease. Both chloroquine and artemisinin-combination therapy (ACT) are highly effective for uncomplicated knowlesi malaria, with faster parasite clearance times and lower anaemia rates with ACT. Given the difficulties with microscope diagnosis of P. knowlesi, a unified treatment strategy of ACT for all Plasmodium species is recommended in coendemic regions.
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Affiliation(s)
- Bridget E Barber
- Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina 0810, Northern Territory, Australia; Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu 88586, Sabah, Malaysia
| | - Matthew J Grigg
- Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina 0810, Northern Territory, Australia; Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu 88586, Sabah, Malaysia
| | - Timothy William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu 88586, Sabah, Malaysia; Queen Elizabeth Hospital Clinical Research Centre, Kota Kinabalu 88586, Sabah, Malaysia; Jesselton Medical Centre, Kota Kinabalu 88300, Sabah, Malaysia
| | - Tsin W Yeo
- Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina 0810, Northern Territory, Australia; Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu 88586, Sabah, Malaysia; Lee Kong Chian School of Medicine, Nanyang Technological University, 639798 Singapore; Communicable Disease Centre, Institute of Infectious Diseases and Epidemiology, Tan Tock Seng Hospital, 308433 Singapore
| | - Nicholas M Anstey
- Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina 0810, Northern Territory, Australia; Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu 88586, Sabah, Malaysia.
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15
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Bird EM, Parameswaran U, William T, Khoo TM, Grigg MJ, Aziz A, Marfurt J, Yeo TW, Auburn S, Anstey NM, Barber BE. Transfusion-transmitted severe Plasmodium knowlesi malaria in a splenectomized patient with beta-thalassaemia major in Sabah, Malaysia: a case report. Malar J 2016; 15:357. [PMID: 27405869 PMCID: PMC4942937 DOI: 10.1186/s12936-016-1398-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/16/2016] [Indexed: 12/25/2022] Open
Abstract
Background Transfusion-transmitted malaria (TTM) is a well-recognized risk of receiving blood transfusions, and has occurred with Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. The simian parasite Plasmodium knowlesi is also known to be transmissible through inoculation of infected blood, and this species is now the most common cause of malaria in Malaysia with a high rate of severity and fatal cases reported. No confirmed case of accidental transfusion-transmitted P. knowlesi has yet been reported. Case presentation A 23-year old splenectomized patient with beta thalassaemia major presented with fever 11 days after receiving a blood transfusion from a pre-symptomatic donor who presented with knowlesi malaria 12 days following blood donation. The infection resulted in severe disease in the recipient, with a parasite count of 84,000/µL and associated metabolic acidosis and multi-organ failure. She was treated with intravenous artesunate and made a good recovery. Sequencing of a highly diverse 649-base pair fragment of the P. knowlesi bifunctional dihydrofolate reductase-thymidylate synthase gene (pkdhfr) revealed that the recipient and donor shared the same haplotype. Conclusions This case demonstrates that acquisition of P. knowlesi from blood transfusion can occur, and that clinical consequences can be severe. Furthermore, this case raises the possibility that thalassaemic patients, particularly those who are splenectomized, may represent a high-risk group for TTM and severe malaria. With rising P. knowlesi incidence, further studies in Sabah are required to determine the risk of TTM in order to guide screening strategies for blood transfusion services.
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Affiliation(s)
- Elspeth M Bird
- Infectious Diseases Society Sabah Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, 88586, Sabah, Malaysia
| | - Uma Parameswaran
- Infectious Diseases Society Sabah Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, 88586, Sabah, Malaysia
| | - Timothy William
- Infectious Diseases Society Sabah Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, 88586, Sabah, Malaysia.,Queen Elizabeth Hospital Clinical Research Centre, Kota Kinabalu, 88586, Malaysia.,Jesselton Medical Centre, Kota Kinabalu, 88300, Sabah, Malaysia
| | - Tien Meng Khoo
- Intensive Care Unit, Queen Elizabeth Hospital, Kota Kinabalu, 88586, Sabah, Malaysia
| | - Matthew J Grigg
- Infectious Diseases Society Sabah Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, 88586, Sabah, Malaysia.,Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, 0810, NT, Australia
| | - Ammar Aziz
- Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, 0810, NT, Australia
| | - Jutta Marfurt
- Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, 0810, NT, Australia
| | - Tsin W Yeo
- Infectious Diseases Society Sabah Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, 88586, Sabah, Malaysia.,Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, 0810, NT, Australia.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 639798, Singapore
| | - Sarah Auburn
- Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, 0810, NT, Australia
| | - Nicholas M Anstey
- Infectious Diseases Society Sabah Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, 88586, Sabah, Malaysia.,Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, 0810, NT, Australia
| | - Bridget E Barber
- Infectious Diseases Society Sabah Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, 88586, Sabah, Malaysia. .,Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, 0810, NT, Australia.
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