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Tobin RJ, Harrison LE, Tully MK, Lubis IND, Noviyanti R, Anstey NM, Rajahram GS, Grigg MJ, Flegg JA, Price DJ, Shearer FM. Updating estimates of Plasmodium knowlesi malaria risk in response to changing land use patterns across Southeast Asia. PLoS Negl Trop Dis 2024; 18:e0011570. [PMID: 38252650 PMCID: PMC10833542 DOI: 10.1371/journal.pntd.0011570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 02/01/2024] [Accepted: 01/16/2024] [Indexed: 01/24/2024] Open
Abstract
BACKGROUND Plasmodium knowlesi is a zoonotic parasite that causes malaria in humans. The pathogen has a natural host reservoir in certain macaque species and is transmitted to humans via mosquitoes of the Anopheles Leucosphyrus Group. The risk of human P. knowlesi infection varies across Southeast Asia and is dependent upon environmental factors. Understanding this geographic variation in risk is important both for enabling appropriate diagnosis and treatment of the disease and for improving the planning and evaluation of malaria elimination. However, the data available on P. knowlesi occurrence are biased towards regions with greater surveillance and sampling effort. Predicting the spatial variation in risk of P. knowlesi malaria requires methods that can both incorporate environmental risk factors and account for spatial bias in detection. METHODS & RESULTS We extend and apply an environmental niche modelling framework as implemented by a previous mapping study of P. knowlesi transmission risk which included data up to 2015. We reviewed the literature from October 2015 through to March 2020 and identified 264 new records of P. knowlesi, with a total of 524 occurrences included in the current study following consolidation with the 2015 study. The modelling framework used in the 2015 study was extended, with changes including the addition of new covariates to capture the effect of deforestation and urbanisation on P. knowlesi transmission. DISCUSSION Our map of P. knowlesi relative transmission suitability estimates that the risk posed by the pathogen is highest in Malaysia and Indonesia, with localised areas of high risk also predicted in the Greater Mekong Subregion, The Philippines and Northeast India. These results highlight areas of priority for P. knowlesi surveillance and prospective sampling to address the challenge the disease poses to malaria elimination planning.
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Affiliation(s)
- Ruarai J. Tobin
- Infectious Disease Dynamics Unit, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Lucinda E. Harrison
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
| | - Meg K. Tully
- Infectious Disease Dynamics Unit, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Inke N. D. Lubis
- Department of Paediatrics, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia
| | - Rintis Noviyanti
- Eijkman Research Center for Molecular Biology, BRIN, Jakarta, Indonesia
| | - Nicholas M. Anstey
- Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Giri S. Rajahram
- Infectious Diseases Society Kota Kinabalu Sabah, Menzies School of Health Research, Clinical Research Unit, Hospital Queen Elizabeth II, and Clinical Research Centre, Queen Elizabeth Hospital, Ministry of Health, Kota Kinabalu, Malaysia
| | - Matthew J. Grigg
- Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Jennifer A. Flegg
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
| | - David J. Price
- Infectious Disease Dynamics Unit, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
- Doherty Institute for Infection and Immunity, The Royal Melbourne Hospital and The University of Melbourne, Melbourne, Australia
| | - Freya M. Shearer
- Infectious Disease Dynamics Unit, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
- Infectious Disease Ecology and Modelling Group, Telethon Kids Institute, Perth, Australia
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Putaporntip C, Cheng CW, Rojrung R, Kuamsab N, Jongwutiwes S. Non-human primate malaria in travellers. J Travel Med 2023; 30:taad135. [PMID: 37856519 DOI: 10.1093/jtm/taad135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/09/2023] [Indexed: 10/21/2023]
Abstract
Emerging zoonotic malaria caused by Plasmodium knowlesi, Plasmodium cynomolgi and Plasmodium inui occurred in humans amid a decline of malaria prevalence in Thailand during the past decade. Diagnosis of non-human primate malaria in ecotourists is challenging. Molecular diagnosis seems to be mandatory such as species-specific polymerase chain reaction (PCR) and targeted amplicon deep sequencing.
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Affiliation(s)
- Chaturong Putaporntip
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Chew Weng Cheng
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds LS2 9JT, UK
| | - Rattanaporn Rojrung
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Napaporn Kuamsab
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
- Community Public Health Program, Faculty of Health Science and Technology, Southern College of Technology, Nakorn Si Thammarat 80110, Thailand
| | - Somchai Jongwutiwes
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
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Charoenwisedsil R, Asawapaithulsert P, Pisutsan P, Chotivanich K, Matsee W. Challenges of Plasmodium vivax and Plasmodium knowlesi co-infection. J Travel Med 2023; 30:taad120. [PMID: 37694850 DOI: 10.1093/jtm/taad120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 09/12/2023]
Abstract
A Burmese man was diagnosed with severe Plasmodium vivax (P. vivax) malaria infection admitted to a hospital in Thailand. Interestingly, following RT-PCR analysis, infections with both P. vivax and Plasmodium knowlesi were identified, potentially contributing to severe manifestation. Co-infection risk, especially in severe P. vivax cases, warrants vigilant consideration.
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Affiliation(s)
- Rachata Charoenwisedsil
- Thai Travel Clinic, Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Punyisa Asawapaithulsert
- Thai Travel Clinic, Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Phimphan Pisutsan
- Thai Travel Clinic, Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Kesinee Chotivanich
- Thai Travel Clinic, Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Wasin Matsee
- Thai Travel Clinic, Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
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Watson QD, Carias LL, Malachin A, Redinger KR, Bosch J, Bardelli M, Baldor L, Feufack-Donfack LB, Popovici J, Moon RW, Draper SJ, Zimmerman PA, King CL. Human monoclonal antibodies inhibit invasion of transgenic Plasmodium knowlesi expressing Plasmodium vivax Duffy binding protein. Malar J 2023; 22:369. [PMID: 38049801 PMCID: PMC10696754 DOI: 10.1186/s12936-023-04766-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 10/24/2023] [Indexed: 12/06/2023] Open
Abstract
BACKGROUND Plasmodium vivax has been more resistant to various control measures than Plasmodium falciparum malaria because of its greater transmissibility and ability to produce latent parasite forms. Therefore, developing P. vivax vaccines and therapeutic monoclonal antibodies (humAbs) remains a high priority. The Duffy antigen receptor for chemokines (DARC) expressed on erythrocytes is central to P. vivax invasion of reticulocytes. P. vivax expresses a Duffy binding protein (PvDBP) on merozoites, a DARC ligand, and the DARC: PvDBP interaction is critical for P. vivax blood stage malaria. Therefore, PvDBP is a leading vaccine candidate for P. vivax and a target for therapeutic human monoclonal antibodies (humAbs). METHODS Here, the functional activity of humAbs derived from naturally exposed and vaccinated individuals are compared for the first time using easily cultured Plasmodium knowlesi (P. knowlesi) that had been genetically modified to replace its endogenous PkDBP orthologue with PvDBP to create a transgenic parasite, PkPvDBPOR. This transgenic parasite requires DARC to invade human erythrocytes but is not reticulocyte restricted. This model was used to evaluate the invasion inhibition potential of 12 humAbs (9 naturally acquired; 3 vaccine-induced) targeting PvDBP individually and in combinations using growth inhibition assays (GIAs). RESULTS The PvDBP-specific humAbs demonstrated 70-100% inhibition of PkPvDBPOR invasion with the IC50 values ranging from 51 to 338 µg/mL for the 9 naturally acquired (NA) humAbs and 33 to 99 µg/ml for the 3 vaccine-induced (VI) humAbs. To evaluate antagonistic, additive, or synergistic effects, six pairwise combinations were performed using select humAbs. Of these combinations tested, one NA/NA (099100/094083) combination demonstrated relatively strong additive inhibition between 10 and 100 µg/mL; all combinations of NA and VI humAbs showed additive inhibition at concentrations below 25 µg/mL and antagonism at higher concentrations. None of the humAb combinations showed synergy. Invasion inhibition efficacy by some mAbs shown with PkPvDBPOR was closely replicated using P. vivax clinical isolates. CONCLUSION The PkPvDBPOR transgenic model is a robust surrogate of P. vivax to assess invasion and growth inhibition of human monoclonal Abs recognizing PvDBP individually and in combination. There was no synergistic interaction for growth inhibition with the humAbs tested here that target different epitopes or subdomains of PvDBP, suggesting little benefit in clinical trials using combinations of these humAbs.
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Affiliation(s)
- Quentin D Watson
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Lenore L Carias
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Alyssa Malachin
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Karli R Redinger
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Jürgen Bosch
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | | | - Lea Baldor
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | | | - Jean Popovici
- Malaria Research Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Robert W Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Simon J Draper
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Peter A Zimmerman
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
| | - Christopher L King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
- Veterans Affairs Medical Center, Cleveland, OH, USA.
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Naserrudin NA, Lin PYP, Monroe A, Baumann SE, Adhikari B, Miller AC, Sato S, Fornace KM, Culleton R, Cheah PY, Hod R, Jeffree MS, Ahmed K, Hassan MR. Disentangling the intersection of inequities with health and malaria exposure: key lessons from rural communities in Northern Borneo. Malar J 2023; 22:343. [PMID: 37946259 PMCID: PMC10636872 DOI: 10.1186/s12936-023-04750-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/11/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND The increasing incidence of Plasmodium knowlesi malaria poses a significant challenge to efforts to eliminate malaria from Malaysia. Macaque reservoirs, outdoors-biting mosquitoes, human activities, and agricultural work are key factors associated with the transmission of this zoonotic pathogen. However, gaps in knowledge regarding reasons that drive malaria persistence in rural Kudat, Sabah, Northern Borneo remain. This study was conducted to address this knowledge gap, to better understand the complexities of these entangled problems, and to initiate discussion regarding new countermeasures to address them. This study aims to highlight rural community members' perspectives regarding inequities to health relating to P. knowlesi malaria exposure. METHODS From January to October 2022, a study using qualitative methods was conducted in four rural villages in Kudat district of Sabah, Malaysia. A total of nine in-depth interviews were conducted with community and faith leaders, after the completion of twelve focus group discussions with 26 photovoice participants. The interviews were conducted using the Sabah Malay dialect, audio-recorded, transcribed, and translated into English. The research team led the discussion and analysis, which was approved by participants through member checking at the community level. RESULTS Participants identified disparity in health as a key issue affecting their health and livelihoods. Injustice in the social environment was also identified as a significant challenge, including the importance of listening to the voices of affected communities in disentangling the social and economic phenomena that can impact malaria control. Specific concerns included inadequate access to health-related resources and degradation of the environment. Participants recommended improving access to water and other necessities, increasing the availability of malaria control commodities in healthcare facilities, and developing sustainable programs to reduce socioeconomic disparities. CONCLUSION Inequities to health emerged as a key concern for malaria control in rural Kudat, Sabah. A locally targeted malaria programme cantered on improving the social and economic disparities associated with health outcomes, could be a potential strategy for malaria prevention in such areas. Community-level perspectives gathered from this study can be used as a foundation for future discussions and dialogues among policymakers and community members for achieving greater transparency, improving social equity, and interoperability in addressing P. knowlesi malaria control.
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Affiliation(s)
- Nurul Athirah Naserrudin
- Department of Public Health Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000, Kuala Lumpur, Malaysia
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia
- Sabah State Health Department, Ministry of Health, 88590, Kota Kinabalu, Malaysia
| | - Pauline Yong Pau Lin
- Faculty of Social Sciences and Humanities, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Malaysia
| | - April Monroe
- Johns Hopkins Center for Communication Programs, Baltimore, MD, USA
| | - Sara Elizabeth Baumann
- Department of Behavioral and Community Health Sciences, University of Pittsburgh School of Public Health, Pittsburgh, PA, 15261, USA
| | - Bipin Adhikari
- 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, Oxford, UK
| | | | - Shigeharu Sato
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia
- Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Malaysia
| | - Kimberly M Fornace
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Richard Culleton
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan
| | - Phaik Yeong Cheah
- 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, Oxford, UK
- The Ethox Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Rozita Hod
- Department of Public Health Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000, Kuala Lumpur, Malaysia
| | - Mohammad Saffree Jeffree
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia
- Department of Public Health Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Malaysia
| | - Kamruddin Ahmed
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia
- Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Malaysia
| | - Mohd Rohaizat Hassan
- Department of Public Health Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000, Kuala Lumpur, Malaysia.
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia.
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Chaturvedi R, Biswas S, Bisht K, Sharma A. The threat of increased transmission of non- knowlesi zoonotic malaria in humans: a systematic review. Parasitology 2023; 150:1167-1177. [PMID: 37929579 PMCID: PMC10801384 DOI: 10.1017/s003118202300077x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 07/17/2023] [Accepted: 07/27/2023] [Indexed: 11/07/2023]
Abstract
Of the 5 human malarial parasites, Plasmodium falciparum and Plasmodium vivax are the most prevalent species globally, while Plasmodium malariae, Plasmodium ovale curtisi and Plasmodium ovale wallikeri are less prevalent and typically occur as mixed-infections. Plasmodium knowlesi, previously considered a non-human primate (NHP) infecting species, is now a cause of human malaria in Malaysia. The other NHP Plasmodium species, Plasmodium cynomolgi, Plasmodium brasilianum, Plasmodium inui, Plasmodium simium, Plasmodium coatneyi and Plasmodium fieldi cause malaria in primates, which are mainly reported in southeast Asia and South America. The non-knowlesi NHP Plasmodium species also emerged and were found to cross-transmit from their natural hosts (NHP) – to human hosts in natural settings. Here we have reviewed and collated data from the literature on the NHPs-to-human-transmitting non-knowlesi Plasmodium species. It was observed that the natural transmission of these NHP parasites to humans had been reported from 2010 onwards. This study shows that: (1) the majority of the non-knowlesi NHP Plasmodium mixed species infecting human cases were from Yala province of Thailand; (2) mono/mixed P. cynomolgi infections with other human-infecting Plasmodium species were prevalent in Malaysia and Thailand and (3) P. brasilianum and P. simium were found in Central and South America.
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Affiliation(s)
- Rini Chaturvedi
- Molecular Medicine Group, International Centre for Genetic Engineering & Biotechnology, New Delhi, India
| | - Shibani Biswas
- Molecular Medicine Group, International Centre for Genetic Engineering & Biotechnology, New Delhi, India
- Host–Parasite Biology, ICMR-National Institute of Malaria Research, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Kanika Bisht
- Host–Parasite Biology, ICMR-National Institute of Malaria Research, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Amit Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering & Biotechnology, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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Pramasivan S, Ngui R, Jeyaprakasam NK, Low VL, Liew JWK, Vythilingam I. Spatial analyses of Plasmodium knowlesi vectors with reference to control interventions in Malaysia. Parasit Vectors 2023; 16:355. [PMID: 37814287 PMCID: PMC10563288 DOI: 10.1186/s13071-023-05984-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/25/2023] [Indexed: 10/11/2023] Open
Abstract
BACKGROUND Malaria parasites such as Plasmodium knowlesi, P. inui, and P. cynomolgi are spread from macaques to humans through the Leucosphyrus Group of Anopheles mosquitoes. It is crucial to know the distribution of these vectors to implement effective control measures for malaria elimination. Plasmodium knowlesi is the most predominant zoonotic malaria parasite infecting humans in Malaysia. METHODS Vector data from various sources were used to create distribution maps from 1957 to 2021. A predictive statistical model utilizing logistic regression was developed using significant environmental factors. Interpolation maps were created using the inverse distance weighted (IDW) method and overlaid with the corresponding environmental variables. RESULTS Based on the IDW analysis, high vector abundances were found in the southwestern part of Sarawak, the northern region of Pahang and the northwestern part of Sabah. However, most parts of Johor, Sabah, Perlis, Penang, Kelantan and Terengganu had low vector abundance. The accuracy test indicated that the model predicted sampling and non-sampling areas with 75.3% overall accuracy. The selected environmental variables were entered into the regression model based on their significant values. In addition to the presence of water bodies, elevation, temperature, forest loss and forest cover were included in the final model since these were significantly correlated. Anopheles mosquitoes were mainly distributed in Peninsular Malaysia (Titiwangsa range, central and northern parts), Sabah (Kudat, West Coast, Interior and Tawau division) and Sarawak (Kapit, Miri, and Limbang). The predicted Anopheles mosquito density was lower in the southern part of Peninsular Malaysia, the Sandakan Division of Sabah and the western region of Sarawak. CONCLUSION The study offers insight into the distribution of the Leucosphyrus Group of Anopheles mosquitoes in Malaysia. Additionally, the accompanying predictive vector map correlates well with cases of P. knowlesi malaria. This research is crucial in informing and supporting future efforts by healthcare professionals to develop effective malaria control interventions.
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Affiliation(s)
- Sandthya Pramasivan
- Department of Parasitology, Faculty of Medicine, Universiti Malaya (UM), Kuala Lumpur, Malaysia
| | - Romano Ngui
- Department of ParaClinical Sciences, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak (UNIMAS), Sarawak, Malaysia.
| | - Nantha Kumar Jeyaprakasam
- Biomedical Science Program, Center for Toxicology and Health Risk Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Van Lun Low
- Tropical Infectious Diseases Research & Education Centre (TIDREC), Universiti Malaya (UM), Kuala Lumpur, Malaysia
| | | | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, Universiti Malaya (UM), Kuala Lumpur, Malaysia.
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Naserrudin NA, Jiee SF, Habil B, Jantim A, Mohamed AFB, Dony JJF, Ibrahim SSA, Fornace KM, Hassan MR, Jeffree MS, Hod R, Culleton R, Ahmed K. The public health response to a Plasmodium malariae outbreak in Penampang district, Sabah during a COVID-19 movement control order. Malar J 2023; 22:292. [PMID: 37789320 PMCID: PMC10546630 DOI: 10.1186/s12936-023-04693-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 08/29/2023] [Indexed: 10/05/2023] Open
Abstract
BACKGROUND Since 2018, no indigenous human malaria cases has been reported in Malaysia. However, during the recent COVID-19 pandemic the World Health Organization is concerned that the pandemic might erode the success of malaria control as there are reports of increase malaria cases in resource limited countries. Little is known how the COVID-19 pandemic has impacted malaria in middle-income countries like Malaysia. Here the public health response to a Plasmodium malariae outbreak occurred in a village in Sabah state, Malaysia, during a COVID-19 movement control order is reported. METHODS An outbreak was declared following the detection of P. malariae in July 2020 and active case detection for malaria was performed by collecting blood samples from residents residing within 2 km radius of Moyog village. Vector prevalence and the efficacy of residual insecticides were determined. Health awareness programmes were implemented to prevent future outbreaks. A survey was conducted among villagers to understand risk behaviour and beliefs concerning malaria. RESULTS A total of 5254 blood samples collected from 19 villages. Among them, 19 P. malariae cases were identified, including the index case, which originated from a man who returned from Indonesia. His return from Indonesia and healthcare facilities visit coincided with the movement control order during COVID-19 pandemic when the healthcare facilities stretched its capacity and only serious cases were given priority. Despite the index case being a returnee from a malaria endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities. All cases were symptomatic and uncomplicated except for a pregnant woman with severe malaria. There were no deaths; all patients recovered following treatment with artemether-lumefantrine combination therapy. Anopheles balabacensis and Anopheles barbirostris were detected in ponds, puddles and riverbeds. The survey revealed that fishing and hunting during night, and self-treatment for mild symptoms contributed to the outbreak. Despite the index case being a returnee from a malaria-endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities. CONCLUSION The outbreak occurred during a COVID-19 movement control order, which strained healthcare facilities, prioritizing only serious cases. Healthcare workers need to be more aware of the risk of malaria from individuals who return from malaria endemic areas. To achieve malaria elimination and prevention of disease reintroduction, new strategies that include multisectoral agencies and active community participation are essential for a more sustainable malaria control programme.
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Affiliation(s)
- Nurul Athirah Naserrudin
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Malaysia
- Sabah State Health Department, Ministry of Health, Kota Kinabalu, Malaysia
| | - Sam Froze Jiee
- Department of Community Medicine and Public Health, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Kota Samarahan, Malaysia
| | - Bobby Habil
- Penampang District Health Office, Ministry of Health, Kota Kinabalu, Malaysia
| | - Anisah Jantim
- Penampang District Health Office, Ministry of Health, Kota Kinabalu, Malaysia
| | | | | | | | - Kimberly M Fornace
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
- Faculty of Infectious and Tropical Diseases and Centre for Climate Change and Planetary Health, London School of Hygiene and Tropical Medicine, London, UK
- Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore, Singapore
| | - Mohd Rohaizat Hassan
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Malaysia
| | - Mohammad Saffree Jeffree
- Department of Public Health Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Malaysia
| | | | - Kamruddin Ahmed
- Borneo Medical Health and Research Centre,, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia.
- Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia.
- Research Center for Global and Local Infectious Diseases, Oita University, Oita, Japan.
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Chang CY. Clinical characteristics and outcome of severe malaria in Kapit, Sarawak, Malaysian Borneo. J Vector Borne Dis 2023; 60:432-434. [PMID: 38174522 DOI: 10.4103/0972-9062.374238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024] Open
Abstract
Background & objectives Severe malaria is a medical emergency and can lead to severe complications and death if not treated promptly and appropriately. Along with Plasmodium falciparum, P. knowlesi is increasingly recognised as a significant cause of fatal and severe malaria. Methods We performed a retrospective review on 54 cases of severe malaria in a district hospital in Kapit, Sarawak, from January 2018 to May 2019. The patients' demographics, clinical features, complications based on organ involvement, and treatment outcomes were examined. Results There were 54 cases of severe malaria, with the majority being male (70%) and between the ages of 40 and 49 (26%). All patients with severe malaria were febrile or had a history of pyrexia except for one patient. P. knowlesi (81.5%) was the most common species causing severe malaria in our study, followed by P. falciparum (13%), and P. vivax (5.5%). There were no cases of severe malaria caused by P. ovale or P. malariae. Hyperparasitaemia was present in 76% of patients and the median parasitemia value at hospital admission was 33,944 parasites/μL (interquartile range: 19,920-113,285 parasites/μL). Circulatory shock was observed in 17 patients (31.5%). There were eight patients with acute renal failure and six patients with respiratory distress. One patient died as a result of severe malaria with multiorgan involvement (1.9% fatality rate). Interpretation & conclusion P. knowlesi is the most common cause of severe malaria in Kapit, Sarawak, Malaysia. Recognizing symptoms of severe malaria and prompt administration of antimalarial are critical for good clinical outcomes.
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Affiliation(s)
- Chee Yik Chang
- Medical Department, Hospital Kapit, Jalan Mamora, Kapit, Sarawak, Malaysia
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10
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Fornace KM, Topazian HM, Routledge I, Asyraf S, Jelip J, Lindblade KA, Jeffree MS, Ruiz Cuenca P, Bhatt S, Ahmed K, Ghani AC, Drakeley C. No evidence of sustained nonzoonotic Plasmodium knowlesi transmission in Malaysia from modelling malaria case data. Nat Commun 2023; 14:2945. [PMID: 37263994 PMCID: PMC10235043 DOI: 10.1038/s41467-023-38476-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 05/02/2023] [Indexed: 06/03/2023] Open
Abstract
Reported incidence of the zoonotic malaria Plasmodium knowlesi has markedly increased across Southeast Asia and threatens malaria elimination. Nonzoonotic transmission of P. knowlesi has been experimentally demonstrated, but it remains unknown whether nonzoonotic transmission is contributing to increases in P. knowlesi cases. Here, we adapt model-based inference methods to estimate RC, individual case reproductive numbers, for P. knowlesi, P. falciparum and P. vivax human cases in Malaysia from 2012-2020 (n = 32,635). Best fitting models for P. knowlesi showed subcritical transmission (RC < 1) consistent with a large reservoir of unobserved infection sources, indicating P. knowlesi remains a primarily zoonotic infection. In contrast, sustained transmission (RC > 1) was estimated historically for P. falciparum and P. vivax, with declines in RC estimates observed over time consistent with local elimination. Together, this suggests sustained nonzoonotic P. knowlesi transmission is highly unlikely and that new approaches are urgently needed to control spillover risks.
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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, Singapore.
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | - Hillary M Topazian
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Isobel Routledge
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
- University of California, San Francisco, San Francisco, USA
| | - Syafie Asyraf
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Jenarun Jelip
- Vector-borne Disease Control Division, Ministry of Health Malaysia, Putrajaya, Malaysia
| | - Kim A Lindblade
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | | | - Pablo Ruiz Cuenca
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Samir Bhatt
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
- Section of Epidemiology, University of Copenhagen, Copenhagen, Denmark
| | - Kamruddin Ahmed
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Azra C Ghani
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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11
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Tan AF, Thota P, Sakam SSB, Lew YL, Rajahram GS, William T, Barber BE, Kho S, Anstey NM, Bell D, Grigg MJ. Evaluation of a point-of-care haemozoin assay (Gazelle device) for rapid detection of Plasmodium knowlesi malaria. Sci Rep 2023; 13:4760. [PMID: 36959462 PMCID: PMC10036474 DOI: 10.1038/s41598-023-31839-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/17/2023] [Indexed: 03/25/2023] Open
Abstract
Plasmodium knowlesi is the major cause of zoonotic malaria in Southeast Asia. Rapid and accurate diagnosis enables effective clinical management. A novel malaria diagnostic tool, Gazelle (Hemex Health, USA) detects haemozoin, a by-product of haem metabolism found in all Plasmodium infections. A pilot phase refined the Gazelle haemozoin identification algorithm, with the algorithm then tested against reference PCR in a larger cohort of patients with P. knowlesi mono-infections and febrile malaria-negative controls. Limit-of-detection analysis was conducted on a subset of P. knowlesi samples serially diluted with non-infected whole blood. The pilot phase of 40 P. knowlesi samples demonstrated 92.5% test sensitivity. P. knowlesi-infected patients (n = 203) and febrile controls (n = 44) were subsequently enrolled. Sensitivity and specificity of the Gazelle against reference PCR were 94.6% (95% CI 90.5-97.3%) and 100% (95% CI 92.0-100%) respectively. Positive and negative predictive values were 100% and 98.8%, respectively. In those tested before antimalarial treatment (n = 143), test sensitivity was 96.5% (95% CI 92.0-98.9%). Sensitivity for samples with ≤ 200 parasites/µL (n = 26) was 84.6% (95% CI 65.1-95.6%), with the lowest parasitaemia detected at 18/µL. Limit-of-detection (n = 20) was 33 parasites/µL (95% CI 16-65%). The Gazelle device has the potential for rapid, sensitive detection of P. knowlesi infections in endemic areas.
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Affiliation(s)
- Angelica F Tan
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, PO Box 41096, Casuarina, NT, 0810, Australia.
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia.
| | | | - Sitti Saimah Binti Sakam
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Yao Long Lew
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, PO Box 41096, Casuarina, NT, 0810, Australia
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Giri S Rajahram
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- Hospital Queen Elizabeth II, Kota Kinabalu, Sabah, Malaysia
- Clinical Research Centre, Queen Elizabeth Hospital, Ministry of Health, Kota Kinabalu, Sabah, Malaysia
| | - Timothy William
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- Clinical Research Centre, Queen Elizabeth Hospital, Ministry of Health, Kota Kinabalu, Sabah, Malaysia
| | - Bridget E Barber
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, PO Box 41096, Casuarina, NT, 0810, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Steven Kho
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, PO Box 41096, Casuarina, NT, 0810, Australia
| | - Nicholas M Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, PO Box 41096, Casuarina, NT, 0810, Australia
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | | | - Matthew J Grigg
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, PO Box 41096, Casuarina, NT, 0810, Australia.
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia.
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Naserrudin NA, Hod R, Saffree Jeffree M, Ahmed K, Hassan MR. International modified Delphi study on malaria preventive behaviour: new themes, contexts and framework for future research on Plasmodium knowlesi malaria. BMJ Open 2023; 13:e067451. [PMID: 36898744 PMCID: PMC10008207 DOI: 10.1136/bmjopen-2022-067451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
Abstract
INTRODUCTION Plasmodium knowlesi malaria is a non-human simian malaria that threatens Southeast Asian rural communities. Studies indicate that non-compliant bednet usage, travelling into the forest and working as farmers and rubber tappers put communities at risk for infection. Despite guidelines, malaria incidence increases yearly and has become a public health concern. In addition to research gaps addressing factors that influence malaria prevention behaviour in these communities, there are no specific guidelines to facilitate strategies against the threat of P. knowlesi malaria. METHOD To examine potential factors that influence malaria-prevention behaviour in communities exposed to P. knowlesi malaria, 12 malaria experts participated in a modified Delphi study; every participant maintained their anonymity throughout the study. Three Delphi rounds were conducted via different online platforms between 15 November 2021 and 26 February 2022, and consensus was achieved when 70% of the participants agreed on a particular point with a 4-5 median. The results from the open-ended questions were then subjected to thematic analysis, and the dataset generated by this study was analysed using a deductive and inductive approach. RESULTS After a systematic, iterative process, knowledge and belief, social support, cognitive and environmental factors, past experience as a malaria patient, and the affordability and feasibility of a given intervention were critical contributors to malaria-prevention behaviour. CONCLUSION Future research on P. knowlesi malaria could adapt this study's findings for a more nuanced understanding of factors that influence malaria-prevention behaviour and improve P. knowlesi malaria programmes based on the expert consensus.
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Affiliation(s)
- Nurul Athirah Naserrudin
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur, Malaysia
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- Sabah State Health Department, Ministry of Health, Kota Kinabalu, Sabah, Malaysia
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur, Malaysia
| | - Mohammad Saffree Jeffree
- Department of Public Health Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Kamruddin Ahmed
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Mohd Rohaizat Hassan
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur, Malaysia
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
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13
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Naserrudin NA, Culleton R, Pau Lin PY, Baumann SE, Hod R, Jeffree MS, Ahmed K, Hassan MR. Generating Trust in Participatory Research on Plasmodium knowlesi Malaria: A Study with Rural Community Gatekeepers during the COVID-19 Pandemic. Int J Environ Res Public Health 2022; 19:ijerph192315764. [PMID: 36497837 PMCID: PMC9737837 DOI: 10.3390/ijerph192315764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/15/2022] [Accepted: 11/23/2022] [Indexed: 06/01/2023]
Abstract
BACKGROUND Plasmodium knowlesi malaria is a zoonotic infection that affects rural communities in South East Asia. Although the epidemiology of the disease has been extensively researched, the voices of individuals within affected communities often go unheard. Here, we describe a study that explores the importance of gatekeepers in conducting research among rural communities, their perspectives on the challenges encountered when attempting to avoid malaria infection, and their views on participatory research. METHODS Between 1 November 2021 and 28 February 2022, we conducted a study in Kudat district, Sabah, using a multi-method design. All participants consented to the study, which included health care workers (HCWs) (n = 5), community leaders (n = 8), and faith leaders (n = 1). We conducted interviews, transect walks, and observations with gatekeepers to ensure data trustworthiness. All interviews were conducted in the Sabah Malay dialect. The sessions were audio- and video-recorded, transcribed into English and analyzed using thematic analysis. RESULTS Between 2017 and 2021, the number of cases of P. knowlesi malaria detected in humans ranged from 35 to 87 in villages under the care of the Lotong primary health care clinic. The challenges in controlling malaria include social norms, lifestyles, socioeconomic factors, environmental factors, and limitations of basic resources. Critical discussions regarding participation with the gatekeepers identified that face-to-face interviews were preferable to online discussions, and influenced willingness to participate in future research. CONCLUSION This study was conducted among village gatekeepers during the COVID-19 pandemic and generated information to drive methodological changes, opening up new ideas by sharing perspectives on challenges in P. knowlesi malaria control among vulnerable communities. The study generated trust in the community and expanded knowledge regarding participation that is critical for future community-based studies.
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Affiliation(s)
- Nurul Athirah Naserrudin
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
- Sabah State Health Department, Ministry of Health, Kota Kinabalu 88590, Malaysia
| | - Richard Culleton
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, Matsuyama 791-0295, Japan
| | - Pauline Yong Pau Lin
- Faculty of Social Sciences and Humanities, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
| | - Sara Elizabeth Baumann
- Department of Behavioral and Community Health Sciences, School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
| | - Mohammad Saffree Jeffree
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
- Department of Public Health Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
| | - Kamruddin Ahmed
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
- Department of Public Health Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
| | - Mohd Rohaizat Hassan
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
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Tan AF, Sakam SSB, Rajahram G, William T, Abd Rachman Isnadi M, Daim S, Barber B, Kho S, Sutherland CJ, Anstey NM, Yerlikaya S, van Schalkwyk DA, Grigg MJ. Diagnostic accuracy and limit of detection of ten malaria parasite lactate dehydrogenase-based rapid tests for Plasmodium knowlesi and P. falciparum. Front Cell Infect Microbiol 2022; 12:1023219. [PMID: 36325471 PMCID: PMC9618705 DOI: 10.3389/fcimb.2022.1023219] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 09/26/2022] [Indexed: 11/21/2022] Open
Abstract
Background Plasmodium knowlesi causes zoonotic malaria across Southeast Asia. First-line diagnostic microscopy cannot reliably differentiate P. knowlesi from other human malaria species. Rapid diagnostic tests (RDTs) designed for P. falciparum and P. vivax are used routinely in P. knowlesi co-endemic areas despite potential cross-reactivity for species-specific antibody targets. Methods Ten RDTs were evaluated: nine to detect clinical P. knowlesi infections from Malaysia, and nine assessing limit of detection (LoD) for P. knowlesi (PkA1-H.1) and P. falciparum (Pf3D7) cultures. Targets included Plasmodium-genus parasite lactate dehydrogenase (pan-pLDH) and P. vivax (Pv)-pLDH. Results Samples were collected prior to antimalarial treatment from 127 patients with microscopy-positive PCR-confirmed P. knowlesi mono-infections. Median parasitaemia was 788/µL (IQR 247-5,565/µL). Pan-pLDH sensitivities ranged from 50.6% (95% CI 39.6–61.5) (SD BIOLINE) to 87.0% (95% CI 75.1–94.6) (First Response® and CareStart™ PAN) compared to reference PCR. Pv-pLDH RDTs detected P. knowlesi with up to 92.0% (95% CI 84.3-96.7%) sensitivity (Biocredit™). For parasite counts ≥200/µL, pan-pLDH (Standard Q) and Pv-pLDH RDTs exceeded 95% sensitivity. Specificity of RDTs against 26 PCR-confirmed negative controls was 100%. Sensitivity of six highest performing RDTs were not significantly different when comparing samples taken before and after (median 3 hours) antimalarial treatment. Parasite ring stages were present in 30% of pre-treatment samples, with ring stage proportions (mean 1.9%) demonstrating inverse correlation with test positivity of Biocredit™ and two CareStart™ RDTs. For cultured P. knowlesi, CareStart™ PAN demonstrated the lowest LoD at 25 parasites/µL; LoDs of other pan-pLDH ranged from 98 to >2000 parasites/µL. Pv-pLDH LoD for P. knowlesi was 49 parasites/µL. No false-positive results were observed in either P. falciparum-pLDH or histidine-rich-protein-2 channels. Conclusion Selected RDTs demonstrate sufficient performance for detection of major human malaria species including P. knowlesi in co-endemic areas where microscopy is not available, particularly for higher parasite counts, although cannot reliably differentiate among non-falciparum malaria.
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Affiliation(s)
- Angelica F. Tan
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- *Correspondence: Angelica F. Tan, ; Matthew J. Grigg,
| | - Sitti Saimah binti Sakam
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Giri S. Rajahram
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- Clinical Research Centre, Queen Elizabeth Hospital, Ministry of Health, Kota Kinabalu, Sabah, Malaysia
- Department of Medicine, Queen Elizabeth Hospital II, Kota Kinabalu, Sabah, Malaysia
| | - Timothy William
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- Clinical Research Centre, Queen Elizabeth Hospital, Ministry of Health, Kota Kinabalu, Sabah, Malaysia
| | | | - Sylvia Daim
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Bridget E. Barber
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
- Clinical Malaria, Queensland Institute of Medical Research (QIMR) Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Steven Kho
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
| | - Colin J. Sutherland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Nicholas M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Seda Yerlikaya
- Malaria and Fever, Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | - Donelly A. van Schalkwyk
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Matthew J. Grigg
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, N T, Australia
- Infectious Diseases Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- *Correspondence: Angelica F. Tan, ; Matthew J. Grigg,
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15
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Haron FN, Azazi A, Chua KH, Lim YAL, Lee PC, Chew CH. In silico structural modeling and quality assessment of Plasmodium knowlesi apical membrane antigen 1 using comparative protein models. Trop Biomed 2022; 39:394-401. [PMID: 36214436 DOI: 10.47665/tb.39.3.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Plasmodium knowlesi is the most common zoonotic parasite associated with human malaria infection in Malaysia. Apical membrane antigen 1 (AMA1) protein in the parasite plays a critical role in parasite invasion into host cells. To date, there is no complete three-dimensional ectodomain structure of P. knowlesi AMA1 (PkAMA1) protein. The knowledge of a protein structure is important to understand the protein molecular functions. Three in silico servers with respective structure prediction methods were used in this study, i.e., SWISS-MODEL for homology modeling and Phyre2 for protein threading, which are template-based modeling, while I-TASSER for template-free ab initio modeling. Two query sequences were used in the study, i.e., native ectodomain of PkAMA1 strain H protein designated as PkAMA1-H and a modified PkAMA1 (mPkAMA1) protein sequence in adaptation for Pichia pastoris expression. The quality of each model was assessed by ProSA-web, QMEAN and SAVES v6.0 (ERRAT, Verify3D and Ramachandran plot) servers. Generated models were then superimposed with two models of Plasmodium AMA1 deposited in Protein Data Bank (PDB), i.e., PkAMA1 (4UV6.B) and Plasmodium vivax AMA1 (PvAMA1, 1W81) protein structures for similarity assessment, quantified by root-meansquare deviation (RMSD) value. SWISS-MODEL, Phyre2 and I-TASSER server generated two, one and five models, respectively. All models are of good quality according to ProSA-web assessment. Based on the average values of model quality assessment and superimposition, the models that recorded highest values for most parameters were selected as best predicted models, i.e., model 2 for both PkAMA1-H and mPkAMA1 from SWISS-MODEL as well as model 1 of PkAMA1-H and model 3 of mPkAMA1 from I-TASSER. Template-based method is useful if known template is available, but template-free method is more suitable if there is no known available template. Generated models can be used as guidance in further protein study that requires protein structural data, i.e., protein-protein interaction study.
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Affiliation(s)
- F N Haron
- Faculty of Health Sciences, Universiti Sultan Zainal Abidin, 21300 Kuala Nerus, Terengganu, Malaysia
| | - A Azazi
- Faculty of Health Sciences, Universiti Sultan Zainal Abidin, 21300 Kuala Nerus, Terengganu, Malaysia
| | - K H Chua
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Y A L Lim
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - P C Lee
- Faculty of Science and Natural Resources, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia
- Biotechnology Research Institute, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia
| | - C H Chew
- Faculty of Health Sciences, Universiti Sultan Zainal Abidin, 21300 Kuala Nerus, Terengganu, Malaysia
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Bin Said I, Kouakou YI, Omorou R, Bienvenu AL, Ahmed K, Culleton R, Picot S. Systematic review of Plasmodium knowlesi in Indonesia: a risk of emergence in the context of capital relocation to Borneo? Parasit Vectors 2022; 15:258. [PMID: 35850777 PMCID: PMC9290274 DOI: 10.1186/s13071-022-05375-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/23/2022] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The Indonesian Republic plans to relocate its capital from Jakarta to East Kalimantan, Borneo Island, in the next few years. This relocation may be associated with deforestation, decreased biodiversity, and an increased risk of emerging zoonotic infections, including Plasmodium knowlesi malaria. The Malaysian part of Borneo Island is one of the main hotspots of P. knowlesi malaria. METHODS Considering this risk, we evaluated the transmission dynamics of P. knowlesi in the Indonesian Archipelago based on a literature search and extensive review of data from the Indonesian Ministry of Health. RESULTS We report that 545 P. knowlesi cases were documented in Indonesia, mainly in the Aceh and North Sumatra provinces, with 95% of these occurring in the last 4 years. CONCLUSIONS The main P. knowlesi vectors are present in the area of the future capital, requiring strengthened surveillance to reduce the risk of emerging cases in a rapidly growing population.
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Affiliation(s)
- Ibrahim Bin Said
- Malaria Research Unit, UMR 5246 CNRS-INSA-CPE-University Lyon1, University Lyon, 69100 Villeurbanne, France
- Institut Agama Islam Negeri (IAIN) Kediri, Jawa Timur, 64127 Kota Kediri, Indonesia
| | - Yobouet Ines Kouakou
- Malaria Research Unit, UMR 5246 CNRS-INSA-CPE-University Lyon1, University Lyon, 69100 Villeurbanne, France
| | - Roukayatou Omorou
- Malaria Research Unit, UMR 5246 CNRS-INSA-CPE-University Lyon1, University Lyon, 69100 Villeurbanne, France
| | - Anne-Lise Bienvenu
- Malaria Research Unit, UMR 5246 CNRS-INSA-CPE-University Lyon1, University Lyon, 69100 Villeurbanne, France
- Service Pharmacie, Groupement Hospitalier Nord, Hospices Civils de Lyon, 69004 Lyon, France
| | - Kamruddin Ahmed
- Faculty of Medicine and Health Sciences, Borneo Medical and Health Research Centre, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah Malaysia
- Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Sabah Malaysia
| | - Richard Culleton
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Stephane Picot
- Malaria Research Unit, UMR 5246 CNRS-INSA-CPE-University Lyon1, University Lyon, 69100 Villeurbanne, France
- Institute of Parasitology and Medical Mycology, Hôpital de La Croix-Rousse, Hospices Civils de Lyon, 69004 Lyon, France
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17
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Sam J, Shamsusah NA, Ali AH, Hod R, Hassan MR, Agustar HK. Prevalence of simian malaria among macaques in Malaysia (2000–2021): A systematic review. PLoS Negl Trop Dis 2022; 16:e0010527. [PMID: 35849568 PMCID: PMC9292078 DOI: 10.1371/journal.pntd.0010527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 05/23/2022] [Indexed: 11/19/2022] Open
Abstract
Background The aim of Malaysia to eliminate malaria nationwide by 2020 seems need to be prolonged. Whilst Malaysia has successfully eliminated human malaria transmission, simian malaria parasites such as Plasmodium knowlesi, P. cynomolgi, P. inui and P. cynomolgi are the emerging cause of malaria in humans. The epidemiological study of simian malaria in primates provides useful information in identifying the risk of human-macaques Plasmodium infection. Methodology/Principal findings This study was performed to gather all available data in terms of simian malaria epidemiology study among macaques in Malaysia over the last two decades. This systematic review was conducted according to the PRISMA guidelines to select appropriate articles as references. Data searches were performed through international databases such as Google Scholar, PubMed, CrossRef, Scopus, Web of Science and Science Direct for original articles published from 2000 until 2021. The review identified seven simian malaria epidemiology studies in Malaysia over the 20-year study period. Most studies were conducted in Peninsular Malaysia (5/7; 71%) followed by East Malaysia (2/7; 29%). All studies showed positive detection of Plasmodium parasites in macaques. The most prevalent Plasmodium species in macaques was P. inui (49.27%) and the least prevalent was P. fieldi (4.76%). The prevalence of simian malaria was higher in East Malaysia compared to Peninsular Malaysia. The mono, dual and triple infection types were the most common among macaques. Conclusion/Significance The non-human primates like macaques are the reservoir of simian plasmodium in Malaysia. Hence, the study of host epidemiology is an important insight to public health management as there is a high occurrence of simian malaria in Malaysia. The right measurement can be taken as well to prevent the transmission of simian malaria from macaques to humans. Macaques are the most abundant primates in south east Asia including Malaysia. Due to deforestation, macaques came closer to human settlements searching for food. Macaques like the long-tailed and pig-tailed harbouring several Plasmodium species that can cause zoonotic malaria in humans. Close contact of human and macaques cause zoonotic transmission of simian malaria. The simian plasmodium such as P. knowlesi, P. inui and P. cynomolgi have been found infecting humans in Malaysia; mainly in East Malaysia (Borneo). Zoonotic malaria poses great risk to public health as prolonged in treatment often lead to fatal outcomes. Hence the knowledge of prevalence and diversity is important to access, this can therefore enlighten the authorities to plan a control strategy that will minimize the zoonotic transmission between non-human primate host to human. This systematic review has summarised all publish data of macaques-plasmodium infection from the year 2000–2021 by using PRISMA guidelines. Our result showed that P. inui (49.27%) is the most prevalent Plasmodium species found in macaques, followed by P. cynomolgi (33.05%) and P. knowlesi (26.86%). Simian plasmodium prevalent was also found higher in East Malaysia (97.0%) compared to Peninsular Malaysia (45.18%). The significant increase of simian malaria incidences in human have jeopardized the national malaria elimination programme. Hence, this study provides a compact insight into the plasmodium epidemiology of macaques in Malaysia.
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Affiliation(s)
- Janeeca Sam
- Department of Bioscience and Biotechnology, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Nadia Aqilla Shamsusah
- Department of Earth Sciences and Environment, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Amatul Hamizah Ali
- Department of Chemical Sciences, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
- * E-mail: (HKA); (RH)
| | - Mohd Rohaizat Hassan
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Hani Kartini Agustar
- Department of Earth Sciences and Environment, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
- * E-mail: (HKA); (RH)
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18
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Naserrudin NA, Culleton R, Hod R, Saffree Jeffree M, Ahmed K, Hassan MR. Exploring the key anthropological drivers of and barriers to zoonotic malaria preventative behaviour in a community exposed to Plasmodium knowlesi infection in Malaysia: protocol for a qualitative study with a participatory research design. BMJ Open 2022; 12:e060866. [PMID: 35772825 PMCID: PMC9247694 DOI: 10.1136/bmjopen-2022-060866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
INTRODUCTION Plasmodium knowlesi malaria is a zoonotic mosquito-borne disease with complex epidemiology. According to the WHO, the prevention and control of vector-borne diseases require community participation to increase coherence between malaria interventions and sustainable public health programmes. We describe a participatory research (PR) design for a study aimed at exploring the key anthropological drivers of and barriers to zoonotic malaria preventive behaviour among communities exposed to P. knowlesi infection in Malaysia. Participatory approaches can facilitate policymakers in designing future zoonotic malaria control programmes by investigating community perspectives and concerns about zoonotic malaria in a local context. METHODS AND ANALYSIS The PR will be conducted over a period of 12 months, from March 2022 to March 2023, among adults (>18 years old) who are permanent residents in a rural village exposed to P. knowlesi malaria in Sabah, Malaysia. We will select patients who were diagnosed with P. knowlesi infection from January to December 2021 for focus group discussions (FGDs), as they can provide perspectives on the disease from the point of view of those previously diagnosed with infection. In-depth interviews (IDIs) with people of importance in the community, such as village heads, will also be conducted. Both FGDs and IDIs will be conducted from March 2022 until June 2022. Concurrently, a photovoice with adults over 18 years old who reside in the community will be conducted. The target sample sizes for FGDs, IDIs and photovoice are 6-8, 12 and 10-15 participants, respectively. We will use a study framework as a theoretical lens to guide the exploration of the beliefs, social contexts, barriers and drivers surrounding zoonotic malaria preventive behaviour. ETHICS AND DISSEMINATION This study has been approved by the Medical Research and Ethics Committee Ministry of Health Malaysia (NMRR ID-21-01980-JEH) and the Research and Innovation Secretariat, Faculty of Medicine, Universiti Kebangsaan Malaysia (FF-2021-462). All participants will provide consent prior to participation. The results will be reported in international peer-reviewed journals and presented at conferences and on other platforms.
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Affiliation(s)
- Nurul Athirah Naserrudin
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Kuala Lumpur, Malaysia
| | - Richard Culleton
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Kuala Lumpur, Malaysia
| | - Mohammad Saffree Jeffree
- Public Health Medicine Department, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Kamruddin Ahmed
- Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Mohd Rohaizat Hassan
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Kuala Lumpur, Malaysia
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19
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Abstract
"The Primate Malarias" book has been a uniquely important resource for multiple generations of scientists, since its debut in 1971, and remains pertinent to the present day. Indeed, nonhuman primates (NHPs) have been instrumental for major breakthroughs in basic and pre-clinical research on malaria for over 50 years. Research involving NHPs have provided critical insights and data that have been essential for malaria research on many parasite species, drugs, vaccines, pathogenesis, and transmission, leading to improved clinical care and advancing research goals for malaria control, elimination, and eradication. Whilst most malaria scientists over the decades have been studying Plasmodium falciparum, with NHP infections, in clinical studies with humans, or using in vitro culture or rodent model systems, others have been dedicated to advancing research on Plasmodium vivax, as well as on phylogenetically related simian species, including Plasmodium cynomolgi, Plasmodium coatneyi, and Plasmodium knowlesi. In-depth study of these four phylogenetically related species over the years has spawned the design of NHP longitudinal infection strategies for gathering information about ongoing infections, which can be related to human infections. These Plasmodium-NHP infection model systems are reviewed here, with emphasis on modern systems biological approaches to studying longitudinal infections, pathogenesis, immunity, and vaccines. Recent discoveries capitalizing on NHP longitudinal infections include an advanced understanding of chronic infections, relapses, anaemia, and immune memory. With quickly emerging new technological advances, more in-depth research and mechanistic discoveries can be anticipated on these and additional critical topics, including hypnozoite biology, antigenic variation, gametocyte transmission, bone marrow dysfunction, and loss of uninfected RBCs. New strategies and insights published by the Malaria Host-Pathogen Interaction Center (MaHPIC) are recapped here along with a vision that stresses the importance of educating future experts well trained in utilizing NHP infection model systems for the pursuit of innovative, effective interventions against malaria.
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Affiliation(s)
- Mary R Galinski
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA.
- Emory Vaccine Center, Emory University, Atlanta, GA, USA.
- Emory National Primate Research Center (Yerkes National Primate Research Center), Emory University, Atlanta, GA, USA.
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20
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Brown R, Salgado-Lynn M, Jumail A, Jalius C, Chua TH, Vythilingam I, Ferguson HM. Exposure of Primate Reservoir Hosts to Mosquito Vectors in Malaysian Borneo. Ecohealth 2022; 19:233-245. [PMID: 35553290 PMCID: PMC9276546 DOI: 10.1007/s10393-022-01586-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 03/05/2022] [Accepted: 03/10/2022] [Indexed: 06/15/2023]
Abstract
Several vector-borne pathogens of primates have potential for human spillover. An example is the simian malaria Plasmodium knowlesi which is now a major public health problem in Malaysia. Characterization of exposure to mosquito vectors is essential for assessment of the force of infection within wild simian populations, however few methods exist to do so. Here we demonstrate the use of thermal imaging and mosquito magnet independence traps (MMIT) to assess the abundance, diversity and infection rates in mosquitoes host seeking near long-tailed macaque (Macaca fasicularis) sleeping sites in the Lower Kinabatangan Wildlife Sanctuary, Malaysian Borneo. The primary Plasmodium knowlesi vector, Anopheles balabacensis, was trapped at higher abundance near sleeping sites than control trees. Although none of the An. balabacensis collected (n = 15) were positive for P. knowlesi by PCR screening, two were infected with another simian malaria Plasmodium inui. Analysis of macaque stools from sleeping sites confirmed a high prevalence of Plasmodium infection, suspected to be P. inui. Recently, natural transmission of P. inui has been detected in humans and An. cracens in Peninsular Malaysia. The presence of P. inui in An. balabacensis here and previously in human-biting collections highlight its potential for spillover from macaques to humans in Sabah. We advocate the use of MMITs for non-invasive sampling of mosquito vectors that host seek on wild simian populations.
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Affiliation(s)
- Rebecca Brown
- Department of Vector Biology, Liverpool School of Tropical Medicine and Hygiene, Liverpool, L3 5QA, UK.
| | - Milena Salgado-Lynn
- Danau Girang Field Centre C/O Sabah Wildlife Department, Wisma Muis, Kota Kinabalu, Sabah, Malaysia
- School of Biosciences and Sustainable Places Research Institute, Cardiff University, Cardiff, UK
- Wildlife Health, Genetic and Forensic Laboratory, Kampung Potuki, Kota Kinabalu, Sabah, Malaysia
| | - Amaziasizamoria Jumail
- Danau Girang Field Centre C/O Sabah Wildlife Department, Wisma Muis, Kota Kinabalu, Sabah, Malaysia
| | - Cyrlen Jalius
- Wildlife Health, Genetic and Forensic Laboratory, Kampung Potuki, Kota Kinabalu, Sabah, Malaysia
| | - Tock-Hing Chua
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Graham Kerr Building, University Avenue, Glasgow, G12 8QQ, UK
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21
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Naserrudin NA, Hod R, Jeffree MS, Ahmed K, Hassan MR. Expert Consensus on a Proposed Study Framework to Explore Factors Influencing Plasmodium knowlesi Malaria Preventive Behavior: A Modified Delphi Method Protocol. Int J Environ Res Public Health 2022; 19:ijerph19074141. [PMID: 35409824 PMCID: PMC8998657 DOI: 10.3390/ijerph19074141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/25/2022] [Accepted: 03/29/2022] [Indexed: 12/10/2022]
Abstract
The increasing incidence of P. knowlesi malaria infection among humans is a public health threat. This zoonotic disease is challenging to eliminate owing to the presence of animal reservoirs. Understanding the factors such as the community’s belief, social context, drivers, and barriers can provide insights into malaria preventive behavior. It is crucial to improve the current preventive measures. This study aims to achieve consensus among malaria experts based on evidence from literature reviews and experts’ opinions on possible factors influencing malaria preventive behavior among communities exposed to P. knowlesi malaria infection. A modified Delphi study protocol was developed to gather experts’ consensus on the study framework to explore the factors influencing preventive behavior among communities exposed to P. knowlesi malaria infection. The framework is adapted from the ideation model, and it is integrated with other relevant theories and extensive literature reviews. We will use the modified Delphi protocol to reach a consensus. The experts will respond to each questionnaire item and a related open-ended questionnaire. Consensus is predetermined at more than 70% agreement on the items. We will use descriptive statistics and thematic analysis to analyze the data. All experts will remain anonymous to maintain the characteristics of a traditional Delphi study.
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Affiliation(s)
- Nurul Athirah Naserrudin
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia; (N.A.N.); (R.H.)
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia; (M.S.J.); (K.A.)
- Sabah State Health Department, Ministry of Health, Kota Kinabalu 88590, Malaysia
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia; (N.A.N.); (R.H.)
| | - Mohammad Saffree Jeffree
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia; (M.S.J.); (K.A.)
- Department of Public Health Medicine, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
| | - Kamruddin Ahmed
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia; (M.S.J.); (K.A.)
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
| | - Mohd Rohaizat Hassan
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia; (N.A.N.); (R.H.)
- Correspondence:
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23
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Gupta A, Styczynski MP, Galinski MR, Voit EO, Fonseca LL. Dramatic transcriptomic differences in Macaca mulatta and Macaca fascicularis with Plasmodium knowlesi infections. Sci Rep 2021; 11:19519. [PMID: 34593836 PMCID: PMC8484567 DOI: 10.1038/s41598-021-98024-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 08/30/2021] [Indexed: 12/02/2022] Open
Abstract
Plasmodium knowlesi, a model malaria parasite, is responsible for a significant portion of zoonotic malaria cases in Southeast Asia and must be controlled to avoid disease severity and fatalities. However, little is known about the host-parasite interactions and molecular mechanisms in play during the course of P. knowlesi malaria infections, which also may be relevant across Plasmodium species. Here we contrast P. knowlesi sporozoite-initiated infections in Macaca mulatta and Macaca fascicularis using whole blood RNA-sequencing and transcriptomic analysis. These macaque hosts are evolutionarily close, yet malaria-naïve M. mulatta will succumb to blood-stage infection without treatment, whereas malaria-naïve M. fascicularis controls parasitemia without treatment. This comparative analysis reveals transcriptomic differences as early as the liver phase of infection, in the form of signaling pathways that are activated in M. fascicularis, but not M. mulatta. Additionally, while most immune responses are initially similar during the acute stage of the blood infection, significant differences arise subsequently. The observed differences point to prolonged inflammation and anti-inflammatory effects of IL10 in M. mulatta, while M. fascicularis undergoes a transcriptional makeover towards cell proliferation, consistent with its recovery. Together, these findings suggest that timely detection of P. knowlesi in M. fascicularis, coupled with control of inflammation while initiating the replenishment of key cell populations, helps contain the infection. Overall, this study points to specific genes and pathways that could be investigated as a basis for new drug targets that support recovery from acute malaria.
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Affiliation(s)
- Anuj Gupta
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Mark P Styczynski
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Mary R Galinski
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, GA, USA
| | - Eberhard O Voit
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
| | - Luis L Fonseca
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Laboratory for Systems Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA
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24
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Byrne I, Aure W, Manin BO, Vythilingam I, Ferguson HM, Drakeley CJ, Chua TH, Fornace KM. Environmental and spatial risk factors for the larval habitats of Plasmodium knowlesi vectors in Sabah, Malaysian Borneo. Sci Rep 2021; 11:11810. [PMID: 34083582 PMCID: PMC8175559 DOI: 10.1038/s41598-021-90893-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 05/18/2021] [Indexed: 12/22/2022] Open
Abstract
Land-use changes, such as deforestation and agriculture, can influence mosquito vector populations and malaria transmission. These land-use changes have been linked to increased incidence in human cases of the zoonotic malaria Plasmodium knowlesi in Sabah, Malaysian Borneo. This study investigates whether these associations are partially driven by fine-scale land-use changes creating more favourable aquatic breeding habitats for P. knowlesi anopheline vectors. Using aerial remote sensing data, we developed a sampling frame representative of all land use types within a major focus of P. knowlesi transmission. From 2015 to 2016 monthly longitudinal surveys of larval habitats were collected in randomly selected areas stratified by land use type. Additional remote sensing data on environmental variables, land cover and landscape configuration were assembled for the study site. Risk factor analyses were performed over multiple spatial scales to determine associations between environmental and spatial variables and anopheline larval presence. Habitat fragmentation (300 m), aspect (350 m), distance to rubber plantations (100 m) and Culex larval presence were identified as risk factors for Anopheles breeding. Additionally, models were fit to determine the presence of potential larval habitats within the areas surveyed and used to generate a time-series of monthly predictive maps. These results indicate that land-use change and topography influence the suitability of larval habitats, and may partially explain the link between P. knowlesi incidence and deforestation. The predictive maps, and identification of the spatial scales at which risk factors are most influential may aid spatio-temporally targeted vector control interventions.
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Affiliation(s)
- Isabel Byrne
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK.
| | - Wilfredo Aure
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
- Research Institute for Tropical Medicine, Manila, Philippines
| | - Benny O Manin
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Chris J Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK
| | - Tock H Chua
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Kimberly M Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, Bloomsbury, London, WCIE 7HT, UK
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25
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Li MI, Mailepessov D, Vythilingam I, Lee V, Lam P, Ng LC, Tan CH. Prevalence of simian malaria parasites in macaques of Singapore. PLoS Negl Trop Dis 2021; 15:e0009110. [PMID: 33493205 PMCID: PMC7861519 DOI: 10.1371/journal.pntd.0009110] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 02/04/2021] [Accepted: 01/06/2021] [Indexed: 02/04/2023] Open
Abstract
Plasmodium knowlesi is a simian malaria parasite currently recognized as the fifth causative agent of human malaria. Recently, naturally acquired P. cynomolgi infection in humans was also detected in Southeast Asia. The main reservoir of both parasites is the long-tailed and pig-tailed macaques, which are indigenous in this region. Due to increased urbanization and changes in land use, there has been greater proximity and interaction between the long-tailed macaques and the general population in Singapore. As such, this study aims to determine the prevalence of simian malaria parasites in local macaques to assess the risk of zoonosis to the general human population. Screening for the presence of malaria parasites was conducted on blood samples from 660 peridomestic macaques collected between Jan 2008 and Mar 2017, and 379 wild macaques collected between Mar 2009 and Mar 2017, using a Pan-Plasmodium-genus specific PCR. Positive samples were then screened using a simian Plasmodium species-specific nested PCR assay to identify the species of parasites (P. knowlesi, P. coatneyi, P. fieldi, P. cynomolgi, and P. inui) present. All the peridomestic macaques sampled were tested negative for malaria, while 80.5% of the 379 wild macaques were infected. All five simian Plasmodium species were detected; P. cynomolgi being the most prevalent (71.5%), followed by P. knowlesi (47.5%), P. inui (42.0%), P. fieldi (32.5%), and P. coatneyi (28.5%). Co-infection with multiple species of Plasmodium parasites was also observed. The study revealed that Singapore's wild long-tailed macaques are natural hosts of the five simian malaria parasite species, while no malaria was detected in all peridomestic macaques tested. Therefore, the risk of simian malaria transmission to the general human population is concluded to be low. However, this can be better demonstrated with the incrimination of the vectors of simian malaria parasites in Singapore.
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Affiliation(s)
- Meizhi Irene Li
- Environmental Health Institute, National Environment Agency, Singapore
| | - Diyar Mailepessov
- Environmental Health Institute, National Environment Agency, Singapore
| | - Indra Vythilingam
- Parasitology Department, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Vernon Lee
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore
| | - Patrick Lam
- Biodefence Centre, Force Medical Protection Command, Headquarters Medical Corps, Singapore Armed Forces, Singapore
| | - Lee Ching Ng
- Environmental Health Institute, National Environment Agency, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Cheong Huat Tan
- Environmental Health Institute, National Environment Agency, Singapore
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Phang WK, Hamid MHA, Jelip J, Mudin RN, Chuang TW, Lau YL, Fong MY. Spatial and Temporal Analysis of Plasmodium knowlesi Infection in Peninsular Malaysia, 2011 to 2018. Int J Environ Res Public Health 2020; 17:ijerph17249271. [PMID: 33322414 PMCID: PMC7764745 DOI: 10.3390/ijerph17249271] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/05/2020] [Accepted: 12/08/2020] [Indexed: 12/12/2022]
Abstract
The life-threatening zoonotic malaria cases caused by Plasmodium knowlesi in Malaysia has recently been reported to be the highest among all malaria cases; however, previous studies have mainly focused on the transmission of P. knowlesi in Malaysian Borneo (East Malaysia). This study aimed to describe the transmission patterns of P. knowlesi infection in Peninsular Malaysia (West Malaysia). The spatial distribution of P. knowlesi was mapped across Peninsular Malaysia using Geographic Information System techniques. Local indicators of spatial associations were used to evaluate spatial patterns of P. knowlesi incidence. Seasonal autoregressive integrated moving average models were utilized to analyze the monthly incidence of knowlesi malaria in the hotspot region from 2012 to 2017 and to forecast subsequent incidence in 2018. Spatial analysis revealed that hotspots were clustered in the central-northern region of Peninsular Malaysia. Time series analysis revealed the strong seasonality of transmission from January to March. This study provides fundamental information on the spatial distribution and temporal dynamic of P. knowlesi in Peninsular Malaysia from 2011 to 2018. Current control policy should consider different strategies to prevent the transmission of both human and zoonotic malaria, particularly in the hotspot region, to ensure a successful elimination of malaria in the future.
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Affiliation(s)
- Wei Kit Phang
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (W.K.P.); (Y.L.L.); (M.Y.F.)
| | - Mohd Hafizi Abdul Hamid
- Disease Control Division, Ministry of Health Malaysia, Putrajaya 62000, Malaysia; (M.H.A.H.); (J.J.); (R.N.M.)
| | - Jenarun Jelip
- Disease Control Division, Ministry of Health Malaysia, Putrajaya 62000, Malaysia; (M.H.A.H.); (J.J.); (R.N.M.)
| | - Rose Nani Mudin
- Disease Control Division, Ministry of Health Malaysia, Putrajaya 62000, Malaysia; (M.H.A.H.); (J.J.); (R.N.M.)
| | - Ting-Wu Chuang
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
- Correspondence: ; Tel.: +886-2-27361661
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (W.K.P.); (Y.L.L.); (M.Y.F.)
| | - Mun Yik Fong
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (W.K.P.); (Y.L.L.); (M.Y.F.)
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Sato S, Tojo B, Hoshi T, Minsong LIF, Kugan OK, Giloi N, Ahmed K, Jeffree SM, Moji K, Kita K. Recent Incidence of Human Malaria Caused by Plasmodium knowlesi in the Villages in Kudat Peninsula, Sabah, Malaysia: Mapping of The Infection Risk Using Remote Sensing Data. Int J Environ Res Public Health 2019; 16:ijerph16162954. [PMID: 31426380 PMCID: PMC6720544 DOI: 10.3390/ijerph16162954] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 08/05/2019] [Indexed: 11/27/2022]
Abstract
Plasmodium knowlesi (Pk) is a malaria parasite that naturally infects macaque monkeys in Southeast Asia. Pk malaria, the zoonosis transmitted from the infected monkeys to the humans by Anopheles mosquito vectors, is now a serious health problem in Malaysian Borneo. To create a strategic plan to control Pk malaria, it is important to estimate the occurrence of the disease correctly. The rise of Pk malaria has been explained as being due to ecological changes, especially deforestation. In this research, we analysed the time-series satellite images of MODIS (MODerate-resolution Imaging Spectroradiometer) of the Kudat Peninsula in Sabah and created the “Pk risk map” on which the Land-Use and Land-Cover (LULC) information was visualised. The case number of Pk malaria of a village appeared to have a correlation with the quantity of two specific LULC classes, the mosaic landscape of oil palm groves and the nearby land-use patches of dense forest, surrounding the village. Applying a Poisson multivariate regression with a generalised linear mixture model (GLMM), the occurrence of Pk malaria cases was estimated from the population and the quantified LULC distribution on the map. The obtained estimations explained the real case numbers well, when the contribution of another risk factor, possibly the occupation of the villagers, is considered. This implies that the occurrence of the Pk malaria cases of a village can be predictable from the population of the village and the LULC distribution shown around it on the map. The Pk risk map will help to assess the Pk malaria risk distributions quantitatively and to discover the hidden key factors behind the spread of this zoonosis.
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Affiliation(s)
- Shigeharu Sato
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Sabah, Malaysia.
- Nagasaki University School of Tropical Medicine and Global Health, Nagasaki 852-8523, Japan.
| | - Bumpei Tojo
- Nagasaki University School of Tropical Medicine and Global Health, Nagasaki 852-8523, Japan
| | - Tomonori Hoshi
- Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan
| | - Lis Izni Fanirah Minsong
- Kudat Health Office, Ministry of Health Malaysia, Beg Berkunci No. 6, Kudat 89059, Sabah, Malaysia
| | - Omar Kwang Kugan
- Kudat Health Office, Ministry of Health Malaysia, Beg Berkunci No. 6, Kudat 89059, Sabah, Malaysia
| | - Nelbon Giloi
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Sabah, Malaysia
| | - Kamruddin Ahmed
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Sabah, Malaysia
| | - Saffree Mohammad Jeffree
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu 88400, Sabah, Malaysia
| | - Kazuhiko Moji
- Nagasaki University School of Tropical Medicine and Global Health, Nagasaki 852-8523, Japan
| | - Kiyoshi Kita
- Nagasaki University School of Tropical Medicine and Global Health, Nagasaki 852-8523, Japan
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Pan B, Pei FQ, Ruan CW, Lin RX, Cen YZ, Liu MR, Deng ZH, Ren WF, Liao YB, Li XH. [Diagnosis and Treatment of the First Imported Case of Plasmodium knowlesi Infection in China]. Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi 2016; 34:513-516. [PMID: 30141606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
OBJECTIVE To diagnose and treat the first imported active case of Plasmodium knowlesi infection in China. METHODS The clinical information of the patient was collected. Microscopy of blood smear was conducted after Giemsa staining. Genomic DNA was extracted from blood, and PCR was conducted to amplify rDNA. The PCR products were sequenced and analyzed with BLAST RESULTS The patient returned from a one-week tour in a tropical rain forest in Malaysia. The first disease attack occurred in Guangzhou on Oct. 16, 2014, with fever, shivering and sweating. The patient was initially diagnosed as malaria and hospitalized on Oct. 26, 2014. Microscopic observation revealed typical forms of P. knowlesi in blood smear. The red blood cells became enlarged, with big trophozoites appearing as a ring with dual cores and dark brown malaria pigment. The trophozoites were slightly bigger and thicker than P. falciparum. The schizont had 6-8 merozoites, with obvious brown malaria pigment. PCR resulted in a specific band of 1 099 bp. BLAST analysis showed that the sequence of the PCR product was 99% homologous to P. knowlesi (acession No. AM910985.1, L07560.1 and AY580317.1). The patient was diagnosed as P. knowlesi infection, and was then given an 8-day treatment with chloroquine and primaquine, together with dihydroartemisinin piperaquine phosphate tablet. The patient was discharged after recovery on Oct. 28, 2014. CONCLUSION According to the clinical symptoms, epidemiological history and laboratory test, the patient has been confirmed as P. knowlesi infection. It may also be the first active case of knowlesi malaria reported in China.
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DEVAKUL K, MAEGRAITH BG. Blood Sugar and Tissue Glycogen in Infections inMacaca Mulattawith the Nuri Strain of Plasmodium Knowlesi. Annals of Tropical Medicine & Parasitology 2016; 52:366-75. [PMID: 13595562 DOI: 10.1080/00034983.1958.11685875] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Grigg MJ, William T, Drakeley CJ, Jelip J, von Seidlein L, Barber BE, Fornace KM, Anstey NM, Yeo TW, Cox J. Factors that are associated with the risk of acquiring Plasmodium knowlesi malaria in Sabah, Malaysia: a case-control study protocol. BMJ Open 2014; 4:e006004. [PMID: 25149186 PMCID: PMC4156811 DOI: 10.1136/bmjopen-2014-006004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
INTRODUCTION Plasmodium knowlesi has long been present in Malaysia, and is now an emerging cause of zoonotic human malaria. Cases have been confirmed throughout South-East Asia where the ranges of its natural macaque hosts and Anopheles leucosphyrus group vectors overlap. The majority of cases are from Eastern Malaysia, with increasing total public health notifications despite a concurrent reduction in Plasmodium falciparum and P. vivax malaria. The public health implications are concerning given P. knowlesi has the highest risk of severe and fatal disease of all Plasmodium spp in Malaysia. Current patterns of risk and disease vary based on vector type and competence, with individual exposure risks related to forest and forest-edge activities still poorly defined. Clustering of cases has not yet been systematically evaluated despite reports of peri-domestic transmission and known vector competence for human-to-human transmission. METHODS AND ANALYSIS A population-based case-control study will be conducted over a 2-year period at two adjacent districts in north-west Sabah, Malaysia. Confirmed malaria cases presenting to the district hospital sites meeting relevant inclusion criteria will be requested to enrol. Three community controls matched to the same village as the case will be selected randomly. Study procedures will include blood sampling and administration of household and individual questionnaires to evaluate potential exposure risks associated with acquisition of P. knowlesi malaria. Secondary outcomes will include differences in exposure variables between P. knowlesi and other Plasmodium spp, risk of severe P. knowlesi malaria, and evaluation of P. knowlesi case clustering. Primary analysis will be per protocol, with adjusted ORs for exposure risks between cases and controls calculated using conditional multiple logistic regression models. ETHICS This study has been approved by the human research ethics committees of Malaysia, the Menzies School of Health Research, Australia, and the London School of Hygiene and Tropical Medicine, UK.
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Affiliation(s)
- M J Grigg
- Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - T William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia Infectious Diseases Unit, Clinical Research Centre, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia Sabah Department of Health, Kota Kinabalu, Sabah, Malaysia
| | - C J Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - J Jelip
- Sabah Department of Health, Kota Kinabalu, Sabah, Malaysia
| | - L von Seidlein
- Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - B E Barber
- Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - K M Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - N M Anstey
- Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - T W Yeo
- Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - J Cox
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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Grigg MJ, William T, Dhanaraj P, Menon J, Barber BE, von Seidlein L, Rajahram G, Price RN, Anstey NM, Yeo TW. A study protocol for a randomised open-label clinical trial of artesunate-mefloquine versus chloroquine in patients with non-severe Plasmodium knowlesi malaria in Sabah, Malaysia (ACT KNOW trial). BMJ Open 2014; 4:e006005. [PMID: 25138814 PMCID: PMC4139630 DOI: 10.1136/bmjopen-2014-006005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
INTRODUCTION Malaria due to Plasmodium knowlesi is reported throughout South-East Asia, and is the commonest cause of it in Malaysia. P. knowlesi replicates every 24 h and can cause severe disease and death. Current 2010 WHO Malaria Treatment Guidelines have no recommendations for the optimal treatment of non-severe knowlesi malaria. Artemisinin-combination therapies (ACT) and chloroquine have each been successfully used to treat knowlesi malaria; however, the rapidity of parasite clearance has not been prospectively compared. Malaysia's national policy for malaria pre-elimination involves mandatory hospital admission for confirmed malaria cases with discharge only after two negative blood films; use of a more rapidly acting antimalarial agent would have health cost benefits. P. knowlesi is commonly microscopically misreported as P. malariae, P. falciparum or P. vivax, with a high proportion of the latter two species being chloroquine-resistant in Malaysia. A unified ACT-treatment protocol would provide effective blood stage malaria treatment for all Plasmodium species. METHODS AND ANALYSIS ACT KNOW, the first randomised controlled trial ever performed in knowlesi malaria, is a two-arm open-label trial with enrolments over a 2-year period at three district sites in Sabah, powered to show a difference in proportion of patients negative for malaria by microscopy at 24 h between treatment arms (clinicaltrials.gov #NCT01708876). Enrolments started in December 2012, with completion expected by September 2014. A total sample size of 228 is required to give 90% power (α 0.05) to determine the primary end point using intention-to-treat analysis. Secondary end points include parasite clearance time, rates of recurrent infection/treatment failure to day 42, gametocyte carriage throughout follow-up and rates of anaemia at day 28, as determined by survival analysis. ETHICS AND DISSEMINATION This study has been approved by relevant institutional ethics committees in Malaysia and Australia. Results will be disseminated to inform knowlesi malaria treatment policy in this region through peer-reviewed publications and academic presentations. TRIAL REGISTRATION NUMBER NCT01708876.
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Affiliation(s)
- M J Grigg
- Global Health and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, KotaKinabalu, Sabah, Malaysia
| | - T William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, KotaKinabalu, Sabah, Malaysia Infectious Diseases Unit, Clinical Research Centre, Queen Elizabeth Hospital, KotaKinabalu, Sabah, Malaysia Sabah Department of Health, KotaKinabalu, Sabah, Malaysia
| | - P Dhanaraj
- Sabah Department of Health, KotaKinabalu, Sabah, Malaysia Kudat District Hospital, Kudat, Sabah, Malaysia
| | - J Menon
- Sabah Department of Health, KotaKinabalu, Sabah, Malaysia
| | - B E Barber
- Global Health and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, KotaKinabalu, Sabah, Malaysia
| | - L von Seidlein
- Global Health and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Mahidol-Oxford Research Unit, Bangkok, Thailand
| | - G Rajahram
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, KotaKinabalu, Sabah, Malaysia Infectious Diseases Unit, Clinical Research Centre, Queen Elizabeth Hospital, KotaKinabalu, Sabah, Malaysia
| | - R N Price
- Global Health and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Nuffield Department of Clinical Medicine, Centre for Tropical Medicine, University of Oxford, Oxford, UK
| | - N M Anstey
- Global Health and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, KotaKinabalu, Sabah, Malaysia Division of Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - T W Yeo
- Global Health and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, KotaKinabalu, Sabah, Malaysia Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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Imai N, White MT, Ghani AC, Drakeley CJ. Transmission and control of Plasmodium knowlesi: a mathematical modelling study. PLoS Negl Trop Dis 2014; 8:e2978. [PMID: 25058400 PMCID: PMC4109903 DOI: 10.1371/journal.pntd.0002978] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 05/12/2014] [Indexed: 12/21/2022] Open
Abstract
Introduction Plasmodium knowlesi is now recognised as a leading cause of malaria in Malaysia. As humans come into increasing contact with the reservoir host (long-tailed macaques) as a consequence of deforestation, assessing the potential for a shift from zoonotic to sustained P. knowlesi transmission between humans is critical. Methods A multi-host, multi-site transmission model was developed, taking into account the three areas (forest, farm, and village) where transmission is thought to occur. Latin hypercube sampling of model parameters was used to identify parameter sets consistent with possible prevalence in macaques and humans inferred from observed data. We then explore the consequences of increasing human-macaque contact in the farm, the likely impact of rapid treatment, and the use of long-lasting insecticide-treated nets (LLINs) in preventing wider spread of this emerging infection. Results Identified model parameters were consistent with transmission being sustained by the macaques with spill over infections into the human population and with high overall basic reproduction numbers (up to 2267). The extent to which macaques forage in the farms had a non-linear relationship with human infection prevalence, the highest prevalence occurring when macaques forage in the farms but return frequently to the forest where they experience higher contact with vectors and hence sustain transmission. Only one of 1,046 parameter sets was consistent with sustained human-to-human transmission in the absence of macaques, although with a low human reproduction number (R0H = 1.04). Simulations showed LLINs and rapid treatment provide personal protection to humans with maximal estimated reductions in human prevalence of 42% and 95%, respectively. Conclusion This model simulates conditions where P. knowlesi transmission may occur and the potential impact of control measures. Predictions suggest that conventional control measures are sufficient at reducing the risk of infection in humans, but they must be actively implemented if P. knowlesi is to be controlled. Plasmodium knowlesi is a malaria of macaques which is now recognised as a leading cause of human malaria in Malaysia. Although current human infections are a result of human-macaque contact, there is a potential for P. knowlesi to be transmitted solely among humans. The authors developed a multi-host, multi-site transmission model to assess the likelihood of this happening due to increased human-macaque contact as a consequence of deforestation, population growth, and land-use change. How effective currently available malaria control measures were against P. knowlesi was also an important issue that was explored using the model. Although the model predicts that conventional control measures will be sufficient against P. knowlesi, with the push to eliminate malaria by the end of 2015, it is crucial to be aware of zoonotic malarias which may undermine such efforts.
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Affiliation(s)
- Natsuko Imai
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- * E-mail:
| | - Michael T. White
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Azra C. Ghani
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Chris J. Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Rajahram GS, Barber BE, Yeo TW, Tan WW, William T. Case report: fatal Plasmodium knowlesi malaria following an atypical clinical presentation and delayed diagnosis. Med J Malaysia 2013; 68:71-72. [PMID: 23466773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- G S Rajahram
- Hospital Keningau, Department of Medicine, Hospital Keningau, Sabah, Malaysia.
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Wiwanitkit V. Human knowlesi malaria and neurological complication: a new thing to be discussed in tropical neurology. Acta Neurol Taiwan 2011; 20:228. [PMID: 22009128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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Singh B, Daneshvar C. Plasmodium knowlesi malaria in Malaysia. Med J Malaysia 2010; 65:166-172. [PMID: 21939162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Plasmodium knowlesi, a simian malaria parasite, is now recognised as the fifth cause of human malaria and can lead to fatal infections in humans. Knowlesi malaria cases are widely distributed in East and West Malaysia and account for more than 50% of admissions for malaria in certain hospitals in the state of Sarawak. This paper will begin with a description of the early studies on P. knowlesi, followed by a review of the epidemiology, diagnosis, clinical and laboratory features, and treatment of knowlesi malaria.
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Affiliation(s)
- B Singh
- Malaria Research Centre, Faculty of Medicine & Health Sciences, Universiti Malaysia Sarawak, 93150 Kuching, Sarawak, Malaysia.
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Lee CE, Adeeba K, Freigang G. Human Plasmodium knowlesi infections in Klang Valley, Peninsula Malaysia: a case series. Med J Malaysia 2010; 65:63-65. [PMID: 21265252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report seven cases of naturally acquired human Plasmodium knowlesi infections which were admitted to our centre from July 2007 till June 2008. Diagnosis was confirmed by nested PCR. Cases of P. knowlesi infections, dubbed the fifth type of human malaria, have been reported in East Malaysia (Sabah and Sarawak) as well as in the state of Pahang in Peninsula Malaysia. These seven patients appear to be the first few reported cases of P. knowlesi infection in the Klang valley, Peninsula Malaysia. We then discuss the characteristics of human P. knowlesi infections, which include its natural hosts, responsible vectors, clinical presentation, and the treatment of such infections.
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Affiliation(s)
- C E Lee
- Infectious Diseases Unit, University Malaya Medical Centre, Kuala Lumpur, Malaysia.
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Wilairatanal P, Krudsood S, Tangpukdee N. Management of Plasmodium knowlesi malaria without PCR confirmation. Southeast Asian J Trop Med Public Health 2010; 41:19-21. [PMID: 20578477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Plasmodium knowlesi morphologically resembles P. malariae; PCR assays are able to differentiate between the 2 species correctly. However, PCR is not available in many hospitals in P. knowlesi endemic areas, particularly in Southeast Asia. In places where PCR is not available, anti-malarial drugs for P. malariae or other non-P. falciparum or P. falciparum species are effective against P. knowlesi. Even with a wrong diagnosis of another malaria species by light microscopy instead of P. knowlesi, the antimalarial drugs given are still effective for treating P. knowlesi infection.
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Affiliation(s)
- Polrat Wilairatanal
- Department of Clinical Tropical Medicine, WHO Collaborating Center for Clinical Management of Malaria, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Lee YCA, Tang CS, Ang LW, Han HK, James L, Goh KT. Epidemiological characteristics of imported and locally-acquired malaria in Singapore. Ann Acad Med Singap 2009; 38:840-849. [PMID: 19890574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
INTRODUCTION The objective of the study was to determine the trend of malaria, the epidemiological characteristics, the frequency of local transmission and the preventive and control measures taken. MATERIALS AND METHODS We analysed the epidemiological records of all reported malaria cases maintained by the Communicable Diseases Division, Ministry of Health, from 1983 to 2007 and the Anopheles vector surveillance data collected by the National Environment Agency during the same period. RESULTS The annual incidence of reported malaria ranged from 2.9 to 11.1 per 100,000 population, with a sharp decline observed after 1997. There were 38 deaths, 92.1% due to falciparum malaria and 7.9% due to vivax malaria. Of the reported cases, 91.4% to 98.3% were imported, with about 90% originating from Southeast Asia and the Indian subcontinent. Among the various population groups with imported malaria, the proportion of cases involving work permit/employment pass holders had increased, while that of local residents had decreased. Between 74.8% and 95.1% of the local residents with imported malaria did not take personal chemoprophylaxis when they travelled overseas. Despite the extremely low Anopheles vector population, a total of 29 local outbreaks involving 196 cases occurred. Most of the larger outbreaks could be traced to foreign workers with imported relapsing vivax malaria and who did not seek medical treatment early. One of the outbreaks of 3 cases in 2007 was caused by Plasmodium knowlesi, a newly recognised simian malaria which was probably acquired in a forested area where long-tail macaques had been sighted. CONCLUSIONS Singapore remains both vulnerable and receptive to the reintroduction of malaria and a high level of vigilance should be maintained indefinitely to prevent the re-establishment of endemicity. Medical practitioners should highlight the risk of malaria to travellers visiting endemic areas and also consider the possibility of simian malaria in a patient who has no recent travel history and presenting with daily fever spikes and with malaria parasite morphologically similar to that of P. malariae.
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Weiss WR, Kumar A, Jiang G, Williams J, Bostick A, Conteh S, Fryauff D, Aguiar J, Singh M, O'Hagan DT, Ulmer JB, Richie TL. Protection of rhesus monkeys by a DNA prime/poxvirus boost malaria vaccine depends on optimal DNA priming and inclusion of blood stage antigens. PLoS One 2007; 2:e1063. [PMID: 17957247 PMCID: PMC2031826 DOI: 10.1371/journal.pone.0001063] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Accepted: 09/11/2007] [Indexed: 11/21/2022] Open
Abstract
Background We have previously described a four antigen malaria vaccine consisting of DNA plasmids boosted by recombinant poxviruses which protects a high percentage of rhesus monkeys against Plasmodium knowlesi (Pk) malaria. This is a multi-stage vaccine that includes two pre-erythrocytic antigens, PkCSP and PkSSP2(TRAP), and two erythrocytic antigens, PkAMA-1 and PkMSP-1(42kD). The present study reports three further experiments where we investigate the effects of DNA dose, timing, and formulation. We also compare vaccines utilizing only the pre-erythrocytic antigens with the four antigen vaccine. Methodology In three experiments, rhesus monkeys were immunized with malaria vaccines using DNA plasmid injections followed by boosting with poxvirus vaccine. A variety of parameters were tested, including formulation of DNA on poly-lactic co-glycolide (PLG) particles, varying the number of DNA injections and the amount of DNA, varying the interval between the last DNA injection to the poxvirus boost from 7 to 21 weeks, and using vaccines with from one to four malaria antigens. Monkeys were challenged with Pk sporozoites given iv 2 to 4 weeks after the poxvirus injection, and parasitemia was measured by daily Giemsa stained blood films. Immune responses in venous blood samples taken after each vaccine injection were measured by ELIspot production of interferon-γ, and by ELISA. Conclusions 1) the number of DNA injections, the formulation of the DNA plasmids, and the interval between the last DNA injection and the poxvirus injection are critical to vaccine efficacy. However, the total dose used for DNA priming is not as important; 2) the blood stage antigens PkAMA-1 and PkMSP-1 were able to protect against high parasitemias as part of a genetic vaccine where antigen folding is not well defined; 3) immunization with PkSSP2 DNA inhibited immune responses to PkCSP DNA even when vaccinations were given into separate legs; and 4) in a counter-intuitive result, higher interferon-γ ELIspot responses to the PkCSP antigen correlated with earlier appearance of parasites in the blood, despite the fact that PkCSP vaccines had a protective effect.
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Affiliation(s)
- Walter R Weiss
- Naval Medical Research Center, Silver Spring, Maryland, United States of America.
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Abstract
Across a large distribution range, population-specific factors as well as pathogen-mediated selection may shape species genetic diversity in the major histocompatibility complex (MHC). We have studied genetic diversity and population differentiation in the MHC region of the Southeast Asian cynomolgus macaque (Macaca fascicularis fascicularis), a species with large and discontinuous range, in order to investigate the role of demography vs selection. Genetic variation was assessed at seven MHC microsatellites on 272 individuals from five populations (Indochina, Java, Borneo, Philippines, and Mauritius). A high genetic diversity was observed in all populations and the Philippines but also the Mauritius populations were the most genetically differentiated. The strength and extent of linkage disequilibrium (LD) (up to 4 Mb) varies across populations mainly because of demographic factors. In Indochina, the complete lack of LD could be the signature of ancient hybridization between cynomolgus and rhesus macaques in the Indochinese peninsula. With the additional support of seven autosomal microsatellites, tests for outlier loci based on intrapopulation diversity and interpopulation differentiation (using F-statistic) allowed to dissociate demographic from selective histories: (i) demographic history may itself explain levels of MHC variability in the Mauritius populations and (ii) positive selection could be responsible for the Philippines population differentiation, especially in the MHC class II region. Among various pathogens, Plasmodium knowlesi and Plasmodium coatneyi are two likely candidates to explain the higher frequency of some MHC haplotypes. Indeed, literature describes low parasitemia in the Philippines individuals, contrasting with fatal infections provoked by these parasites in other cynomolgus macaque populations.
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Affiliation(s)
- M Bonhomme
- Laboratoire UMR 5174 Evolution et Diversité Biologique EDB, Université Paul Sabatier, Toulouse, France.
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Affiliation(s)
- C Rimington
- Department of Chemical Pathology, University College Hospital Medical School and Medical Research Council Farm Laboratories, Mill Hill
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de Brevern AG, Wong H, Tournamille C, Colin Y, Le Van Kim C, Etchebest C. A structural model of a seven-transmembrane helix receptor: The Duffy antigen/receptor for chemokine (DARC). Biochim Biophys Acta Gen Subj 2005; 1724:288-306. [PMID: 16046070 DOI: 10.1016/j.bbagen.2005.05.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 05/13/2005] [Accepted: 05/16/2005] [Indexed: 01/28/2023]
Abstract
The Duffy antigen/receptor for chemokine (DARC) is an erythrocyte receptor for malaria parasites (Plasmodium vivax and Plasmodium knowlesi) and for chemokines. In contrast to other chemokine receptors, DARC is a promiscuous receptor that binds chemokines of both CC and CXC classes. The four extracellular domains (ECDs) of DARC are essential for its interaction with chemokines, whilst the first (ECD1) is sufficient for the interaction with malaria erythrocyte-binding protein. In this study, we elaborate and analyze structural models of the DARC. The construction of the 3D models is based on a comparative modeling process and on the use of many procedures to predict transmembrane segments and to detect far homologous proteins with known structures. Threading, ab initio, secondary structure and Protein Blocks approaches are used to build a very large number of models. The conformational exploration of the ECDs is performed with simulated annealing. The second and fourth ECDs are strongly constrained. On the contrary, the ECD1 is highly flexible, but seems composed of three consecutive regions: a small beta-sheet, a linker region and a structured loop. The chosen structural models encompass most of the biochemical features and reflect the known experimental data. They may be used to analyze functional interaction properties.
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Affiliation(s)
- A G de Brevern
- Equipe de Bioinformatique Génomique et Moléculaire (EBGM), INSERM U 726, Université Denis DIDEROT-Paris 7, case 7113, 2, place Jussieu, 75251 Paris, France.
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Tripathi R, Awasthi A, Dutta GP. Mefloquine resistance reversal action of ketoconazole – a cytochrome P450 inhibitor, against mefloquine-resistant malaria. Parasitology 2005; 130:475-9. [PMID: 15991489 DOI: 10.1017/s0031182004006481] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Plasmodium knowlesi (W1) shows a high level of innate resistance to mefloquine as shown by recrudescence of blood-induced infection in rhesus monkeys, following oral mefloquine treatment with up to 80-160 mg/kg total dose over 3-4 days. Ketoconazole, at a dose of 75 mg/kg/day x 10 days given orally to P. knowlesi-infected rhesus monkeys, exerted a suppressive antimalarial effect in 1 of the 2 monkeys as evidenced by a delayed recrudescence (on day 30) and curative action in case of the other monkey, whereas a lower dose of ketoconazole (25 mg/kg/day x 10 days) failed to suppress infection effectively. When ketoconazole at a low dose (25 mg/kg/day x 10 days) treatment was combined with mefloquine (20 mg/kg/ day x 4), 1 of the 2 infected monkeys was cured, while the combination of a higher dose of ketoconazole (75 mg/kg/day x 10 days) with mefloquine (20 mg/kg/day x 4), had a complete curative effect on P. knowlesi infection in all the treated monkeys (7/7). Besides exerting direct antimalarial action against a mefloquine-resistant P. knowlesi, ketoconazole also acts as an inhibitor of hepatic microsomal CYP4503A, which regulates and slows down mefloquine biotransformation to carboxymefloquine, resulting in a possible elevation of the effective plasma drug level, which seems to be responsible for elimination of the resistant P. knowlesi. The study shows a resistance reversal effect of a ketoconazole - mefloquine combination that could be exploited for the control of mefloquine-resistant malaria infection. The study shows that ketoconazole can reverse mefloquine resistance of P. knowlesi. These findings can also be applied to reverse mefloquine resistance of P.falciparum in areas where mefloquine resistance is already established. The precise role of parasite CYP450 in mefloquine resistance and its possible role, if any, in expelling the intracellular mefloquine from the resistant plasmodia still remains to be elucidated.
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Affiliation(s)
- R Tripathi
- Division of Parasitology, Central Drug Research Institute, Lucknow-226001, India.
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Chen L, Li G, Lu Y, Luo Z. Histopathological changes of Macaca mulatta infected with Plasmodium knowlesi. Chin Med J (Engl) 2001; 114:1073-7. [PMID: 11677770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
OBJECTIVE To study the histopathological changes of relevant internal organs of Macaca mulatta infected with Plasmodium knowlesi (P. knowlesi). METHODS Histopathological examination of 3 monkeys who died of P. knowlesi infection, 2 P. knowlesi infected monkeys who died of treatment failure with artesunate suppository and 1 P. knowlesi infected monkey that was cured by piperaquine phosphate (PQP) but died of trauma and necrosis of the fore limb. RESULTS The heart, liver, spleen, lung, kidney, brain, pancreas, parathyroid, pituitary and lymph nodes showed severe pathological changes in 3 monkeys (No. 1, 7 and 12) who died of P. knowlesi infection and 1 infected monkey (No. 72) who died of treatment failure with artesunate suppository. Red blood cells containing malarial parasites and pigments were concentrated in the capillaries of these organs. Malarial pigments were deposited in many organs or phagocytized by macrophages in 1 monkey (No. 131), it was cured by piperaquine phosphate but died of trauma and necrosis of the fore limb; cellular atrophy and disappearance of pancreatic islets, parathyroid and pituitary cells were also observed. One monkey (No. 33) treated with artesunate suppository, showed that blood parasites became negative but recrudesced and pituitary later died from a gavage accident. Its organs showed a significant difference to those of the infected monkeys receiving no treatment. Only the liver Kupffer cells and cerebral matrix contained malarial parasites and pigments; many relevant internal organs showed repair. CONCLUSION The pathological changes of relevant internal organs of Macaca mulatta infected with P. knowlesi were examined in detail, especially cellular atrophy and the disappearance of pancreatic islets, parathyroid and pituitary cells and myolysis of cardiac muscles. These changes have not previously been reported elsewhere.
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Affiliation(s)
- L Chen
- Department of Malaria, Institute of Tropical Medicine, Guangzhou University of Traditional Chinese Medicine, Guangzhou 510405, China
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Kakinuma C, Futamura Y, Kaga N, Shibutani Y. Plasma cytokine concentrations and splenic changes in cynomolgus monkeys (Macaca fascicularis) with malaria. Lab Anim Sci 1999; 49:101-4. [PMID: 10090104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- C Kakinuma
- Toxicology Laboratory, Mochida Pharmaceutical Co., Ltd., Shizuoka, Japan
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Abstract
Anopheles hackeri, a mosquito commonly found breeding in nipa palm leaf bases along the Malayan coast, was demonstrated to be infected with Plasmodium knowlesi by the inoculation of sporozoites into an uninfected rhesus monkey. This was the first demonstration of a natural vector of any monkey malaria.
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FLETCHER KA, MAEGRAITH BG. Glucose-6-phosphate and 6-phosphogluconate dehydrogenase activities in erythrocytes of monkeys infected with Plasmodium knowlesi. Nature 1998; 196:1316-8. [PMID: 13945524 DOI: 10.1038/1961316b0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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