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Johnson E, Sunil Kumar Sharma R, Ruiz Cuenca P, Byrne I, Salgado-Lynn M, Suraya Shahar Z, Col Lin L, Zulkifli N, Dilaila Mohd Saidi N, Drakeley C, Matthiopoulos J, Nelli L, Fornace K. Landscape drives zoonotic malaria prevalence in non-human primates. eLife 2024; 12:RP88616. [PMID: 38753426 PMCID: PMC11098556 DOI: 10.7554/elife.88616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024] Open
Abstract
Zoonotic disease dynamics in wildlife hosts are rarely quantified at macroecological scales due to the lack of systematic surveys. Non-human primates (NHPs) host Plasmodium knowlesi, a zoonotic malaria of public health concern and the main barrier to malaria elimination in Southeast Asia. Understanding of regional P. knowlesi infection dynamics in wildlife is limited. Here, we systematically assemble reports of NHP P. knowlesi and investigate geographic determinants of prevalence in reservoir species. Meta-analysis of 6322 NHPs from 148 sites reveals that prevalence is heterogeneous across Southeast Asia, with low overall prevalence and high estimates for Malaysian Borneo. We find that regions exhibiting higher prevalence in NHPs overlap with human infection hotspots. In wildlife and humans, parasite transmission is linked to land conversion and fragmentation. By assembling remote sensing data and fitting statistical models to prevalence at multiple spatial scales, we identify novel relationships between P. knowlesi in NHPs and forest fragmentation. This suggests that higher prevalence may be contingent on habitat complexity, which would begin to explain observed geographic variation in parasite burden. These findings address critical gaps in understanding regional P. knowlesi epidemiology and indicate that prevalence in simian reservoirs may be a key spatial driver of human spillover risk.
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Affiliation(s)
- Emilia Johnson
- School of Biodiversity, One Health and Veterinary Medicine, University of GlasgowGlasgowUnited Kingdom
- Department of Disease Control, London School of Hygiene & Tropical MedicineLondonUnited Kingdom
- Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical MedicineLondonUnited Kingdom
| | | | - Pablo Ruiz Cuenca
- Department of Disease Control, London School of Hygiene & Tropical MedicineLondonUnited Kingdom
- Lancaster University, BailriggLancasterUnited Kingdom
- Liverpool School of Tropical Medicine, Pembroke Place LiverpoolLiverpoolUnited Kingdom
| | - Isabel Byrne
- Department of Disease Control, London School of Hygiene & Tropical MedicineLondonUnited Kingdom
| | - Milena Salgado-Lynn
- School of Biosciences, Cardiff UniversityCardiffUnited Kingdom
- Wildlife Health, Genetic and Forensic Laboratory, Sabah Wildlife Department, Wisma MuisKota KinabaluMalaysia
- Danau Girang Field Centre, Sabah Wildlife DepartmentKinabalu SabahMalaysia
| | | | - Lee Col Lin
- Faculty of Veterinary Medicine, Universiti Putra MalaysiaSelangorMalaysia
| | - Norhadila Zulkifli
- Faculty of Veterinary Medicine, Universiti Putra MalaysiaSelangorMalaysia
| | | | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical MedicineLondonUnited Kingdom
| | - Jason Matthiopoulos
- School of Biodiversity, One Health and Veterinary Medicine, University of GlasgowGlasgowUnited Kingdom
| | - Luca Nelli
- School of Biodiversity, One Health and Veterinary Medicine, University of GlasgowGlasgowUnited Kingdom
| | - Kimberly Fornace
- School of Biodiversity, One Health and Veterinary Medicine, University of GlasgowGlasgowUnited Kingdom
- Department of Disease Control, London School of Hygiene & Tropical MedicineLondonUnited Kingdom
- Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical MedicineLondonUnited Kingdom
- Saw Swee Hock School of Public Health, National University of SingaporeSingaporeSingapore
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Davidson G, Speldewinde P, Manin BO, Cook A, Weinstein P, Chua TH. Forest Restoration and the Zoonotic Vector Anopheles balabacensis in Sabah, Malaysia. ECOHEALTH 2024; 21:21-37. [PMID: 38411846 DOI: 10.1007/s10393-024-01675-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 01/16/2024] [Indexed: 02/28/2024]
Abstract
Anthropogenic changes to forest cover have been linked to an increase in zoonotic diseases. In many areas, natural forests are being replaced with monoculture plantations, such as oil palm, which reduce biodiversity and create a mosaic of landscapes with increased forest edge habitat and an altered micro-climate. These altered conditions may be facilitating the spread of the zoonotic malaria parasite Plasmodium knowlesi in Sabah, on the island of Borneo, through changes to mosquito vector habitat. We conducted a study on mosquito abundance and diversity in four different land uses comprising restored native forest, degraded native forest, an oil palm estate and a eucalyptus plantation, these land uses varying in their vegetation types and structure. The main mosquito vector, Anopheles balabacensis, has adapted its habitat preference from closed canopy rainforest to more open logged forest and plantations. The eucalyptus plantations (Eucalyptus pellita) assessed in this study contained significantly higher abundance of many mosquito species compared with the other land uses, whereas the restored dipterocarp forest had a low abundance of all mosquitos, in particular, An. balabacensis. No P. knowlesi was detected by PCR assay in any of the vectors collected during the study; however, P. inui, P. fieldi and P. vivax were detected in An. balabacensis. These findings indicate that restoring degraded natural forests with native species to closed canopy conditions reduces abundance of this zoonotic malarial mosquito vector and therefore should be incorporated into future restoration research and potentially contribute to the control strategies against simian malaria.
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Affiliation(s)
- Gael Davidson
- School of Agriculture and Environment, University of Western Australia, Albany, Australia
- School of Population and Global Health, University of Western Australia, Perth, Australia
| | - Peter Speldewinde
- School of Agriculture and Environment, University of Western Australia, Albany, Australia
| | - Benny Obrain Manin
- Borneo Medical and Health Research Centre (BMHRC), Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Angus Cook
- School of Population and Global Health, University of Western Australia, Perth, Australia
| | - Philip Weinstein
- School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Tock H Chua
- Edulife Berhad, Kota Kinabalu, Sabah, Malaysia.
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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] [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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Pramasivan S, Low VL, Jeyaprakasam NK, Liew JWK, Ngui R, Vythilingam I. Cryptic Diversity and Demographic Expansion of Plasmodium knowlesi Malaria Vectors in Malaysia. Genes (Basel) 2023; 14:1369. [PMID: 37510274 PMCID: PMC10378955 DOI: 10.3390/genes14071369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
Although Malaysia is considered free of human malaria, there has been a growing number of Plasmodium knowlesi cases. This alarming trend highlighted the need for our understanding of this parasite and its associated vectors, especially considering the role of genetic diversity in the adaptation and evolution among vectors in endemic areas, which is currently a significant knowledge gap in their fundamental biology. Thus, this study aimed to investigate the genetic diversity of Anopheles balabacensis, Anopheles cracens, Anopheles introlatus, and Anopheles latens-the vectors for P. knowlesi malaria in Malaysia. Based on cytochrome c oxidase 1 (CO1) and internal transcribed spacer 2 (ITS2) markers, the genealogic networks of An. latens showed a separation of the haplotypes between Peninsular Malaysia and Malaysia Borneo, forming two distinct clusters. Additionally, the genetic distances between these clusters were high (2.3-5.2% for CO1) and (2.3-4.7% for ITS2), indicating the likely presence of two distinct species or cryptic species within An. latens. In contrast, no distinct clusters were observed in An. cracens, An. balabacensis, or An. introlatus, implying a lack of pronounced genetic differentiation among their populations. It is worth noting that there were varying levels of polymorphism observed across the different subpopulations, highlighting some levels of genetic variation within these mosquito species. Nevertheless, further analyses revealed that all four species have undergone demographic expansion, suggesting population growth and potential range expansion for these vectors in this region.
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Affiliation(s)
- Sandthya Pramasivan
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Van Lun Low
- Tropical Infectious Diseases Research & Education Centre (TIDREC), Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Nantha Kumar Jeyaprakasam
- Biomedical Science Program, Center for Toxicology and Health Risk Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia
| | - Jonathan Wee Kent Liew
- Environmental Health Institute, National Environment Agency, Singapore 569874, Singapore
| | - Romano Ngui
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
- Malaria Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak (UNIMAS), Kota Samarahan 94300, Sarawak, Malaysia
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
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Yanmanee S, Seethamchai S, Kuamsab N, Karaphan S, Suwonkerd W, Jongwutiwes S, Putaporntip C. Natural vectors of Plasmodium knowlesi and other primate, avian and ungulate malaria parasites in Narathiwat Province, Southern Thailand. Sci Rep 2023; 13:8875. [PMID: 37264067 DOI: 10.1038/s41598-023-36017-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/27/2023] [Indexed: 06/03/2023] Open
Abstract
To date, four species of simian malaria parasites including Plasmodium knowlesi, P. cynomolgi, P. inui and P. fieldi have been incriminated in human infections in Thailand. Although the prevalence of malaria in macaque natural hosts has been investigated, their vectors remain unknown in this country. Herein, we performed a survey of Anopheles mosquitoes during rainy and dry seasons in Narathiwat Province, Southern Thailand. Altogether 367 Anopheles mosquitoes were captured for 40 nights during 18:00 to 06:00 h by using human-landing catches. Based on morphological and molecular identification, species composition comprised An. maculatus (37.06%), An. barbirostris s.l. (31.34%), An. latens (17.71%), An. introlatus (10.08%) and others (3.81%) including An. umbrosus s.l., An. minimus, An. hyrcanus s.l., An. aconitus, An. macarthuri and An. kochi. Analyses of individual mosquitoes by PCR, sequencing and phylogenetic inference of the mitochondrial cytochrome genes of both malaria parasites and mosquitoes have revealed that the salivary gland samples of An. latens harbored P. knowlesi (n = 1), P. inui (n = 2), P. fieldi (n = 1), P. coatneyi (n = 1), P. hylobati (n = 1) and an unnamed Plasmodium species known to infect both long-tailed and pig-tailed macaques (n = 2). The salivary glands of An. introlatus possessed P. cynomolgi (n = 1), P. inui (n = 1), P. hylobati (n = 1) and coexistence of P. knowlesi and P. inui (n = 1). An avian malaria parasite P. juxtanucleare has been identified in the salivary gland sample of An. latens. Three other distinct lineages of Plasmodium with phylogenetic affinity to avian malaria species were detected in An. latens, An. introlatus and An. macarthuri. Interestingly, the salivary gland sample of An. maculatus contained P. caprae, an ungulate malaria parasite known to infect domestic goats. Most infected mosquitoes harbored multiclonal Plasmodium infections. All Plasmodium-infected mosquitoes were captured during the first quarter of the night and predominantly occurred during rainy season. Since simian malaria in humans has a wide geographic distribution in Thailand, further studies in other endemic areas of the country are mandatory for understanding transmission and prevention of zoonotic malaria.
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Affiliation(s)
- Surasuk Yanmanee
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Department of Biology, Faculty of Science, Naresuan University, Pitsanulok, Thailand
| | - Sunee Seethamchai
- Department of Biology, Faculty of Science, Naresuan University, Pitsanulok, Thailand.
| | - Napaporn Kuamsab
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Community Public Health Program, Faculty of Health Science and Technology, Southern College of Technology, Nakhon Si Thammarat, Thailand
| | - Sunate Karaphan
- Department of National Parks, Wildlife and Plant Conservation, Ministry of National Resources and Environment, Bangkok, Thailand
| | - Wannapa Suwonkerd
- Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | - Somchai Jongwutiwes
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Chaturong Putaporntip
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
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Wong ML, Zulzahrin Z, Vythilingam I, Lau YL, Sam IC, Fong MY, Lee WC. Perspectives of vector management in the control and elimination of vector-borne zoonoses. Front Microbiol 2023; 14:1135977. [PMID: 37025644 PMCID: PMC10070879 DOI: 10.3389/fmicb.2023.1135977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 02/28/2023] [Indexed: 04/08/2023] Open
Abstract
The complex transmission profiles of vector-borne zoonoses (VZB) and vector-borne infections with animal reservoirs (VBIAR) complicate efforts to break the transmission circuit of these infections. To control and eliminate VZB and VBIAR, insecticide application may not be conducted easily in all circumstances, particularly for infections with sylvatic transmission cycle. As a result, alternative approaches have been considered in the vector management against these infections. In this review, we highlighted differences among the environmental, chemical, and biological control approaches in vector management, from the perspectives of VZB and VBIAR. Concerns and knowledge gaps pertaining to the available control approaches were discussed to better understand the prospects of integrating these vector control approaches to synergistically break the transmission of VZB and VBIAR in humans, in line with the integrated vector management (IVM) developed by the World Health Organization (WHO) since 2004.
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Affiliation(s)
- Meng Li Wong
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Zulhisham Zulzahrin
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Indra Vythilingam
- 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
| | - I-Ching Sam
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Medical Microbiology, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
| | - Mun Yik Fong
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Wenn-Chyau Lee
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- A*STAR Infectious Diseases Labs (A*STAR ID Labs), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- *Correspondence: Wenn-Chyau Lee,
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Genetic Diversity, Haplotype Relationships, and kdr Mutation of Malaria Anopheles Vectors in the Most Plasmodium knowlesi-Endemic Area of Thailand. Trop Med Infect Dis 2022; 7:tropicalmed7120412. [PMID: 36548667 PMCID: PMC9786164 DOI: 10.3390/tropicalmed7120412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 11/25/2022] [Accepted: 11/26/2022] [Indexed: 12/04/2022] Open
Abstract
Plasmodium knowlesi, a malaria parasite that occurs naturally in long-tailed macaques, pig-tailed macaques, and banded leaf monkeys, is currently regarded as the fifth of the human malaria parasites. We aimed to investigate genetic diversity based on the cytochrome c oxidase subunit I (COI) gene, detect Plasmodium parasites, and screen for the voltage-gated sodium channel (VGSC)-mutation-mediated knockdown resistance (kdr) of Anopheles mosquitoes in Ranong province, which is the most P. knowlesi-endemic area in Thailand. One hundred and fourteen Anopheles females belonging to eight species, including An. baimaii (21.05%), An. minimus s.s. (20.17%), An. epiroticus (19.30%), An. jamesii (19.30%), An. maculatus s.s. (13.16%), An. barbirostris A3 (5.26%), An. sawadwongporni (0.88%), and An. aconitus (0.88%), were caught in three geographical regions of Ranong province. None of the Anopheles mosquitoes sampled in this study were infected with Plasmodium parasites. Based on the sequence analysis of COI sequences, An. epiroticus had the highest level of nucleotide diversity (0.012), followed by An. minimus (0.011). In contrast, An. maculatus (0.002) had the lowest level of nucleotide diversity. The Fu's Fs and Tajima's D values of the Anopheles species in Ranong were all negative, except the Tajima's D values of An. minimus (0.077). Screening of VGSC sequences showed no presence of the kdr mutation of Anopheles mosquitoes. Our results could be used to further select effective techniques for controlling Anopheles populations in Thailand's most P. knowlesi-endemic area.
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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] [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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9
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Non-Human Primate Malaria Infections: A Review on the Epidemiology in Malaysia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19137888. [PMID: 35805545 PMCID: PMC9265734 DOI: 10.3390/ijerph19137888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/24/2022] [Accepted: 06/25/2022] [Indexed: 02/01/2023]
Abstract
Malaria remains a public health problem in many parts of the world, including Malaysia. Although Malaysia has been recognized as one of the countries free from indigenous human malaria since 2018, the rising trend of zoonotic malaria, particularly Plasmodium knowlesi cases, poses a threat to public health and is of great concern to the country’s healthcare system. We reviewed previously scattered information on zoonotic malaria infections in both Peninsular Malaysia and Malaysian Borneo to determine the epidemiology and distribution of emerging zoonotic malaria infections. Given the high prevalence of zoonotic malaria in Malaysia, efforts should be made to detect zoonotic malaria in humans, mosquito vectors, and natural hosts to ensure the success of the National Malaria Elimination Strategic Plan.
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Ooi CH, Phang WK, Liew JWK, Atroosh WM, Lau YL. Epidemiology of indigenous Plasmodium knowlesi infection in Sarawak, 2011-2019. Trop Med Int Health 2022; 27:705-718. [PMID: 35716113 DOI: 10.1111/tmi.13788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVES To characterize the state-wide epidemiology of indigenous knowlesi malaria in Sarawak from 2011-2019. METHODS Longitudinal retrospective study based on Sarawak knowlesi malaria surveillance data recorded 2011-2019. Only indigenous cases were included and information extracted for analysis comprised age, sex, occupation, ethnicity, case severity, hospital admission, and parasite density. RESULTS Over the 9 years 8473 indigenous knowlesi malaria cases were recorded. Age group 40 to 49 years, males, plantation workers, and Iban communities recorded the highest percentage of cases in each demographic variable. Most of the cases were uncomplicated (85.9%) and 89.5% of the total cases were reported with ≤20,000 parasites/μL of blood. Age group and ethnic group are associated with severity of knowlesi malaria in Sarawak. Multivariable logistic regression indicated that the age group 60+ years had the highest odds of developing severe knowlesi malaria compared to other age groups (AOR 2.48; 95% CI 1.22, 5.02; p=0.012). Bidayuh patients were more likely to develop severe knowlesi malaria than Ibans, the largest ethnic group among knowlesi malaria patients (AOR 1.97; 95% CI 1.31, 2.97; p=0.001). CONCLUSIONS Identification of risk groups is important for the implementation of prevention programs and treatments targeting at specific group to combat knowlesi malaria effectively.
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Affiliation(s)
- Choo Huck Ooi
- Vector Borne Disease Section, Sarawak Health Department, Ministry of Health Malaysia, Sarawak, Malaysia
| | - Wei Kit Phang
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jonathan Wee Kent Liew
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.,Currenly Environmental Health Institute, National Environment Agency, Singapore
| | - Wahib M Atroosh
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.,Department of Microbiology and Parasitology, University of Aden, Aden, Yemen
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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11
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Yusuf NM, Zulkefli J, Jiram AI, Vythilingam I, Hisam S, Devi R, Salehhuddin A, Ali NM, Isa M, Alias N, Ogu salim N, Aziz AA, Sulaiman LH. Plasmodium spp. in macaques, Macaca fascicularis, in Malaysia, and their potential role in zoonotic malaria transmission. Parasite 2022; 29:32. [PMID: 35674419 PMCID: PMC9175634 DOI: 10.1051/parasite/2022032] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/22/2022] [Indexed: 11/14/2022] Open
Abstract
Macaques, Macaca fascicularis, are a known reservoir of Plasmodium knowlesi, the agent of simian malaria which is the predominant zoonotic species affecting humans in Malaysia and other Southeast Asian countries. Recently, a naturally acquired human infection of another simian malaria parasite, P. cynomolgi has been reported. Thus, it is crucial to study the distribution of simian Plasmodium infections with particular attention to the macaques. Four hundred and nineteen (419) long-tailed macaques (Macaca fascicularis) were trapped in selected areas where human cases of P. knowlesi and P. cynomolgi have been reported. Nested polymerase chain reaction (PCR) was conducted to identify the Plasmodium spp., and circumsporozoite protein (CSP) genes of P. knowlesi samples were sequenced. Plasmodium cynomolgi infection was shown to be the most prevalent among the macaque population (68.4%). Although 50.6% of analyzed samples contained single infections either with P. knowlesi, P. cynomolgi, P. inui, P. coatneyi, or P. fieldi, mixed infections with double, triple, quadruple, and all 5 species were also detected. Infection with P. cynomolgi and P. knowlesi were the highest among Malaysian macaques in areas where humans and macaques are in close contact. The risk of zoonotic infection in these areas needs to be addressed since the number of zoonotic malaria cases is on the rise. With the elimination of human malaria, the risk of humans being infected with simian malaria is very high and steps should be taken to mitigate this issue.
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Affiliation(s)
- Noorazian Md Yusuf
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
- Corresponding author: ,
| | - Jannah Zulkefli
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
| | - Adela Ida Jiram
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
| | - Indra Vythilingam
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
- Department of Parasitology, Faculty of Medicine, University of Malaya 50603 Kuala Lumpur Malaysia
| | - Shamilah Hisam
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
| | - Renuka Devi
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
| | - Afiqah Salehhuddin
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
| | - Nurulshuhada Md Ali
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
| | - Maccallyster Isa
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
| | - Norwahida Alias
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
| | - Nurhainis Ogu salim
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
| | - Adli Abd Aziz
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
- School of Biology, Faculty of Applied Sciences, Universiti Teknologi MARA Cawangan Negeri Sembilan Kampus Kuala Pilah, Pekan Parit Tinggi 72000 Kuala Pilah Negeri Sembilan Malaysia
| | - Lokman Hakim Sulaiman
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, Block C3 & C7, Level 2, National Institutes of Health (NIH), Ministry of Health Malaysia No. 1 Jalan Setia Murni U13/52, Seksyen U13, Bandar Setia Alam 40170 Shah Alam Selangor Malaysia
- Centre for Environmental and Population Health, Institute for Research, Development, and Innovation, and Department of Community Medicine, School of Medicine, International Medical University No. 126, Jalan Jalil Perkasa 19, Bukit Jalil 57000 Kuala Lumpur Malaysia
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12
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Lee WC, Cheong FW, Amir A, Lai MY, Tan JH, Phang WK, Shahari S, Lau YL. Plasmodium knowlesi: the game changer for malaria eradication. Malar J 2022; 21:140. [PMID: 35505339 PMCID: PMC9066973 DOI: 10.1186/s12936-022-04131-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/18/2022] [Indexed: 11/12/2022] Open
Abstract
Plasmodium knowlesi is a zoonotic malaria parasite that has gained increasing medical interest over the past two decades. This zoonotic parasitic infection is prevalent in Southeast Asia and causes many cases with fulminant pathology. Despite several biogeographical restrictions that limit its distribution, knowlesi malaria cases have been reported in different parts of the world due to travelling and tourism activities. Here, breakthroughs and key information generated from recent (over the past five years, but not limited to) studies conducted on P. knowlesi were reviewed, and the knowledge gap in various research aspects that need to be filled was discussed. Besides, challenges and strategies required to control and eradicate human malaria with this emerging and potentially fatal zoonosis were described.
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Affiliation(s)
- Wenn-Chyau Lee
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Fei Wen Cheong
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Amirah Amir
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Meng Yee Lai
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jia Hui Tan
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Wei Kit Phang
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Shahhaziq Shahari
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
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13
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van de Straat B, Sebayang B, Grigg MJ, Staunton K, Garjito TA, Vythilingam I, Russell TL, Burkot TR. Zoonotic malaria transmission and land use change in Southeast Asia: what is known about the vectors. Malar J 2022; 21:109. [PMID: 35361218 PMCID: PMC8974233 DOI: 10.1186/s12936-022-04129-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 03/18/2022] [Indexed: 11/28/2022] Open
Abstract
Zoonotic Plasmodium infections in humans in many Southeast Asian countries have been increasing, including in countries approaching elimination of human-only malaria transmission. Most simian malarias in humans are caused by Plasmodium knowlesi, but recent research shows that humans are at risk of many different simian Plasmodium species. In Southeast Asia, simian Plasmodium species are mainly transmitted by mosquitoes in the Anopheles leucosphyrus and Anopheles dirus complexes. Although there is some evidence of species outside the Leucosphyrus Group transmitting simian Plasmodium species, these await confirmation of transmission to humans. The vectors of monkey malarias are mostly found in forests and forest fringes, where they readily bite long-tailed and pig-tailed macaques (the natural reservoir hosts) and humans. How changing land-uses influence zoonotic malaria vectors is still poorly understood. Fragmentation of forests from logging, agriculture and other human activities is associated with increased zoonotic Plasmodium vector exposure. This is thought to occur through altered macaque and mosquito distributions and behaviours, and importantly, increased proximity of humans, macaques, and mosquito vectors. Underlying the increase in vector densities is the issue that the land-use change and human activities create more oviposition sites and, in correlation, increases availably of human blood hosts. The current understanding of zoonotic malaria vector species is largely based on a small number of studies in geographically restricted areas. What is known about the vectors is limited: the data is strongest for distribution and density with only weak evidence for a limited number of species in the Leucosphyrus Group for resting habits, insecticide resistance, blood feeding habits and larval habitats. More data are needed on vector diversity and bionomics in additional geographic areas to understand both the impacts on transmission of anthropogenic land-use change and how this significant disease in humans might be controlled.
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Affiliation(s)
- Bram van de Straat
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia.
| | - Boni Sebayang
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Matthew J Grigg
- Menzies School of Health Research & Charles Darwin University, Casuarina, Australia
| | - Kyran Staunton
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Triwibowo Ambar Garjito
- Institute for Vector and Reservoir Control Research and Development, National Institute of Health Research and Development (NIHRD), The Ministry of Health of Indonesia, Jakarta, Indonesia
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Tanya L Russell
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Thomas R Burkot
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
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14
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Ruiz Cuenca P, Key S, Lindblade KA, Vythilingam I, Drakeley C, Fornace K. Is there evidence of sustained human-mosquito-human transmission of the zoonotic malaria Plasmodium knowlesi? A systematic literature review. Malar J 2022; 21:89. [PMID: 35300703 PMCID: PMC8929260 DOI: 10.1186/s12936-022-04110-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/27/2022] [Indexed: 12/03/2022] Open
Abstract
Background The zoonotic malaria parasite Plasmodium knowlesi has emerged across Southeast Asia and is now the main cause of malaria in humans in Malaysia. A critical priority for P. knowlesi surveillance and control is understanding whether transmission is entirely zoonotic or is also occurring through human-mosquito-human transmission. Methods A systematic literature review was performed to evaluate existing evidence which refutes or supports the occurrence of sustained human-mosquito-human transmission of P. knowlesi. Possible evidence categories and study types which would support or refute non-zoonotic transmission were identified and ranked. A literature search was conducted on Medline, EMBASE and Web of Science using a broad search strategy to identify any possible published literature. Results were synthesized using the Synthesis Without Meta-analysis (SWiM) framework, using vote counting to combine the evidence within specific categories. Results Of an initial 7,299 studies screened, 131 studies were included within this review: 87 studies of P. knowlesi prevalence in humans, 14 studies in non-human primates, 13 studies in mosquitoes, and 29 studies with direct evidence refuting or supporting non-zoonotic transmission. Overall, the evidence showed that human-mosquito-human transmission is biologically possible, but there is limited evidence of widespread occurrence in endemic areas. Specific areas of research were identified that require further attention, notably quantitative analyses of potential transmission dynamics, epidemiological and entomological surveys, and ecological studies into the sylvatic cycle of the disease. Conclusion There are key questions about P. knowlesi that remain within the areas of research that require more attention. These questions have significant implications for malaria elimination and eradication programs. This paper considers limited but varied research and provides a methodological framework for assessing the likelihood of different transmission patterns for emerging zoonotic diseases. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04110-z.
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Affiliation(s)
- Pablo Ruiz Cuenca
- Centre for Health Informatics, Computing, and Statistics (CHICAS), Lancaster University Medical School, Lancaster, UK. .,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | - Stephanie Key
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Kim A Lindblade
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Kimberly Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
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15
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Multiplex PCR Assay for the Identification of Four Species of the Anopheles Leucosphyrus Sub-Group in Malaysia. INSECTS 2022; 13:insects13020195. [PMID: 35206768 PMCID: PMC8878329 DOI: 10.3390/insects13020195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 02/06/2022] [Accepted: 02/11/2022] [Indexed: 11/18/2022]
Abstract
Simple Summary Plasmodium parasites cause malaria. The bites of infected female Anopheles mosquitoes, known as “malaria vectors,” transmit the parasites to people. To prevent the spread of malaria, precise mosquito species identification is essential. This study aims to develop a quick and accurate method for identifying the Anopheles species (An. introlatus, An. latens, An. cracens, and An. balabacensis), which have been incriminated as vectors for simian malaria in Malaysia. Overall, six primers targeting the internal transcribed spacer 2 (ITS2) region of each species were designed for this assay. This study is helpful for the researchers or vector-related field workers to correctly identify the mosquitoes for control activities. Abstract The Leucosphyrus Group of mosquitoes are the major simian malaria vectors in Malaysia. Accurate species identification is required to help in curbing the spread of simian malaria. The aim of the study is to provide an accurate molecular method for identifying the four important Anopheles vector species found in Malaysia. Mosquito specimens were collected from various localities in Malaysia, where simian malaria cases were reported. DNA from 122 mosquito specimens was tested to develop a multiplex polymerase chain reaction (PCR) assay. The specificity of this assay was tested against other mosquito species. Molecular identification of the species was further confirmed by analysing the internal transcribed spacer 2 (ITS2) DNA region of the specimens. Anopheles balabacensis and An. latens showed two distinct clades in the phylogenetic tree. The multiplex PCR assay was developed based on the ITS2 region for the identification of Anopheles introlatus (298–299 bp), Anopheles latens (197–198 bp), Anopheles cracens (421–426 bp), and Anopheles balabacensis (224–228 bp). This method will be useful to accurately identify the major Anopheles Leucosphyrus Group species in Malaysia, which are difficult to identify morphologically, to determine the correct vector as well as its geographical distribution.
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16
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Pramasivan S, Ngui R, Jeyaprakasam NK, Liew JWK, Low VL, Mohamed Hassan N, Wan Sulaiman WY, Jaraee R, Abdul Rahman R, Jelip J, Vythilingam I. Spatial distribution of Plasmodium knowlesi cases and their vectors in Johor, Malaysia: in light of human malaria elimination. Malar J 2021; 20:426. [PMID: 34715864 PMCID: PMC8555301 DOI: 10.1186/s12936-021-03963-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 10/21/2021] [Indexed: 12/03/2022] Open
Abstract
Background Plasmodium knowlesi, a simian malaria parasite infection, increases as Plasmodium falciparum and Plasmodium vivax infections decrease in Johor, Malaysia. Therefore, this study aimed to identify the distribution of vectors involved in knowlesi malaria transmission in Johor. This finding is vital in estimating hotspot areas for targeted control strategies. Methods Anopheles mosquitoes were collected from the location where P. knowlesi cases were reported. Cases of knowlesi malaria from 2011 to 2019 in Johor were analyzed. Internal transcribed spacers 2 (ITS2) and cytochrome c oxidase subunit I (COI) genes were used to identify the Leucosphyrus Group of Anopheles mosquitoes. In addition, spatial analysis was carried out on the knowlesi cases and vectors in Johor. Results One hundred and eighty-nine cases of P. knowlesi were reported in Johor over 10 years. Young adults between the ages of 20–39 years comprised 65% of the cases. Most infected individuals were involved in agriculture and army-related occupations (22% and 32%, respectively). Four hundred and eighteen Leucosphyrus Group Anopheles mosquitoes were captured during the study. Anopheles introlatus was the predominant species, followed by Anopheles latens. Spatial analysis by Kriging interpolation found that hotspot regions of P. knowlesi overlapped or were close to the areas where An. introlatus and An. latens were found. A significantly high number of vectors and P. knowlesi cases were found near the road within 0–5 km. Conclusions This study describes the distribution of P. knowlesi cases and Anopheles species in malaria-endemic transmission areas in Johor. Geospatial analysis is a valuable tool for studying the relationship between vectors and P. knowlesi cases. This study further supports that the Leucosphyrus Group of mosquitoes might be involved in transmitting knowlesi malaria cases in Johor. These findings may provide initial evidence to prioritize diseases and vector surveillance. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03963-0.
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Affiliation(s)
- Sandthya Pramasivan
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Romano Ngui
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.,Malaria Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak (UNIMAS), 94300, Kota Samarahan, Sarawak, Malaysia
| | | | - Jonathan Wee Kent Liew
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.,Environmental Health Institute, National Environment Agency, Singapore, Singapore
| | - Van Lun Low
- Tropical Infectious Diseases Research & Education Centre (TIDREC), Universiti Malaya, Kuala Lumpur, Malaysia
| | - Norzihan Mohamed Hassan
- Entomology & Pest Sector, Disease Control Division, Ministry of Health Malaysia, Putrajaya, Malaysia
| | | | - Ropiah Jaraee
- Entomology & Pest Unit, Johor State Health District Department, Johor, Malaysia
| | | | - Jenarun Jelip
- Disease Control Division, Ministry of Health Malaysia, Putrajaya, Malaysia
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
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17
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Cuenca PR, Key S, Jumail A, Surendra H, Ferguson HM, Drakeley CJ, Fornace K. Epidemiology of the zoonotic malaria Plasmodium knowlesi in changing landscapes. ADVANCES IN PARASITOLOGY 2021; 113:225-286. [PMID: 34620384 DOI: 10.1016/bs.apar.2021.08.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Within the past two decades, incidence of human cases of the zoonotic malaria Plasmodium knowlesi has increased markedly. P. knowlesi is now the most common cause of human malaria in Malaysia and threatens to undermine malaria control programmes across Southeast Asia. The emergence of zoonotic malaria corresponds to a period of rapid deforestation within this region. These environmental changes impact the distribution and behaviour of the simian hosts, mosquito vector species and human populations, creating new opportunities for P. knowlesi transmission. Here, we review how landscape changes can drive zoonotic disease emergence, examine the extent and causes of these changes across Southeast and identify how these mechanisms may be impacting P. knowlesi dynamics. We review the current spatial epidemiology of reported P. knowlesi infections in people and assess how these demographic and environmental changes may lead to changes in transmission patterns. Finally, we identify opportunities to improve P. knowlesi surveillance and develop targeted ecological interventions within these landscapes.
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Affiliation(s)
- Pablo Ruiz Cuenca
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Stephanie Key
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Henry Surendra
- Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia; Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Chris J Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kimberly Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, United Kingdom.
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18
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Vythilingam I, Chua TH, Liew JWK, Manin BO, Ferguson HM. The vectors of Plasmodium knowlesi and other simian malarias Southeast Asia: challenges in malaria elimination. ADVANCES IN PARASITOLOGY 2021; 113:131-189. [PMID: 34620382 DOI: 10.1016/bs.apar.2021.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Plasmodium knowlesi, a simian malaria parasite of great public health concern has been reported from most countries in Southeast Asia and exported to various countries around the world. Currently P. knowlesi is the predominant species infecting humans in Malaysia. Besides this species, other simian malaria parasites such as P. cynomolgi and P. inui are also infecting humans in the region. The vectors of P. knowlesi and other Asian simian malarias belong to the Leucosphyrus Group of Anopheles mosquitoes which are generally forest dwelling species. Continual deforestation has resulted in these species moving into forest fringes, farms, plantations and human settlements along with their macaque hosts. Limited studies have shown that mosquito vectors are attracted to both humans and macaque hosts, preferring to bite outdoors and in the early part of the night. We here review the current status of simian malaria vectors and their parasites, knowledge of vector competence from experimental infections and discuss possible vector control measures. The challenges encountered in simian malaria elimination are also discussed. We highlight key knowledge gaps on vector distribution and ecology that may impede effective control strategies.
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Affiliation(s)
- Indra Vythilingam
- Department of Parasitology, University of Malaya, Kuala Lumpur, Malaysia.
| | - Tock Hing Chua
- Department of Pathobiology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Sabah Malaysia, Kota Kinabalu, Sabah, Malaysia.
| | - Jonathan Wee Kent Liew
- Department of Parasitology, University of Malaya, Kuala Lumpur, Malaysia; Environmental Health Institute, National Environment Agency, Singapore, Singapore
| | - Benny O Manin
- Department of Pathobiology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Sabah Malaysia, Kota Kinabalu, Sabah, Malaysia
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland, United Kingdom
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19
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Molecular epidemiology and population genomics of Plasmodium knowlesi. ADVANCES IN PARASITOLOGY 2021; 113:191-223. [PMID: 34620383 DOI: 10.1016/bs.apar.2021.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular epidemiology has been central to uncovering P. knowlesi as an important cause of human malaria in Southeast Asia, and to understanding the complex nature of this zoonosis. Species-specific parasite detection and characterization of sequences were vital to show that P. knowlesi was distinct from the human parasite species that had been presumed to cause all malaria. With established sensitive and specific molecular detection tools, surveys subsequently indicated the distribution of P. knowlesi infections in humans, wild primate reservoir host species, and mosquito vector species. The importance of studying P. knowlesi genetic polymorphism was indicated initially by analysing a few nuclear gene loci as well as the mitochondrial genome, and subsequently by multi-locus microsatellite analyses and whole-genome sequencing. Different human infections generally have unrelated P. knowlesi genotypes, acquired from the diverse local parasite reservoirs in macaques. However, individual human infections are usually less genetically complex than those of wild macaques which experience more frequent superinfection with different P. knowlesi genotypes. Multi-locus analyses have revealed deep population subdivisions within P. knowlesi, which are structured both geographically and in relation to different macaque reservoir host species. Simplified genotypic discrimination assays now enable efficient large-scale surveillance of the sympatric P. knowlesi subpopulations within Malaysian Borneo. The whole-genome sequence analyses have also identified loci under recent positive natural selection in the P. knowlesi genome, with evidence that different loci are affected in different populations. These provide a foundation to understand recent adaptation of the zoonotic parasite populations, and to track and interpret future changes as they emerge.
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20
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Chin AZ, Avoi R, Atil A, Awang Lukman K, Syed Abdul Rahim SS, Ibrahim MY, Ahmed K, Jeffree MS. Risk factor of plasmodium knowlesi infection in Sabah Borneo Malaysia, 2020: A population-based case-control study. PLoS One 2021; 16:e0257104. [PMID: 34506556 PMCID: PMC8432820 DOI: 10.1371/journal.pone.0257104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/23/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND In the Malaysian state of Sabah, P. knowlesi notifications increased from 2% (59/2,741) of total malaria notifications in 2004 to 98% (2030/2,078) in 2017. There was a gap regarding P. knowlesi acquisition risk factors related to practice specifically in working age group. The main objective of this study was to identify the risk factors for acquiring P. knowlesi infection in Sabah among the working age group. METHODS AND METHODS This retrospective population-based case-control study was conducted in Ranau district to assess sociodemographic, behavioural and medical history risk factors using a pretested questionnaire. The data were entered and analyzed using IBM SPSS version 23. Bivariate analysis was conducted using binary logistic regression whereas multivariate analysis was conducted using multivariable logistic regression. We set a statistical significance at p-value less than or equal to 0.05. RESULTS A total of 266 cases and 532 controls were included in the study. Male gender (AOR = 2.71; 95% CI: 1.63-4.50), spending overnight in forest (AOR = 1.92; 95% CI: 1.20-3.06), not using mosquito repellent (AOR = 2.49; 95% CI: 1.36-4.56) and history of previous malaria infection (AOR = 49.34; 95% CI: 39.09-78.32) were found to be independent predictors of P. knowlesi infection. CONCLUSIONS This study showed the need to strengthen the strategies in preventing and controlling P. knowlesi infection specifically in changing the practice of spending overnight in forest and increasing the usage of personal mosquito repellent.
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Affiliation(s)
- Abraham Zefong Chin
- Faculty of Medicine and Health Sciences, Department of Public Health Medicine, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Richard Avoi
- Faculty of Medicine and Health Sciences, Department of Public Health Medicine, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Azman Atil
- Faculty of Medicine and Health Sciences, Department of Public Health Medicine, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- Faculty of Medicine, Department of Community Health, Universiti Kebangsaan Malaysia Medical Centre, Jalan Yaacob Latiff, Bandar Tun Razak, Cheras, Kuala Lumpur, Malaysia
| | - Khamisah Awang Lukman
- Faculty of Medicine and Health Sciences, Department of Public Health Medicine, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Syed Sharizman Syed Abdul Rahim
- Faculty of Medicine and Health Sciences, Department of Public Health Medicine, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Mohd Yusof Ibrahim
- Faculty of Medicine and Health Sciences, Department of Public Health Medicine, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Kamruddin Ahmed
- Borneo Medical and Health Research Centre, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- Faculty of Medicine and Health Sciences, Department of Pathology and Microbiology, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Mohammad Saffree Jeffree
- Faculty of Medicine and Health Sciences, Department of Public Health Medicine, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- Borneo Medical and Health Research Centre, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
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21
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Ooi CH, Phang WK, Kent Liew JW, Lau YL. Spatial and Temporal Patterns of Plasmodium knowlesi Malaria in Sarawak from 2008 to 2017. Am J Trop Med Hyg 2021; 104:1814-1819. [PMID: 33755585 PMCID: PMC8103491 DOI: 10.4269/ajtmh.20-1304] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/22/2021] [Indexed: 12/16/2022] Open
Abstract
Zoonotic knowlesi malaria has replaced human malaria as the most prevalent malaria disease in Malaysia. The persistence of knowlesi malaria in high-risk transmission areas or hotspots can be discouraging to existing malaria elimination efforts. In this study, retrospective data of laboratory-confirmed knowlesi malaria cases were obtained from the Sarawak Health Department to investigate the spatiotemporal patterns and clustering of knowlesi malaria in the state of Sarawak from 2008 to 2017. Purely spatial, purely temporal, and spatiotemporal analyses were performed using SaTScan software to define clustering of knowlesi malaria incidence. Purely spatial and spatiotemporal analyses indicated most likely clusters of knowlesi malaria in the northern region of Sarawak, along the Sarawak-Kalimantan border, and the inner central region of Sarawak between 2008 and 2017. Temporal cluster was detected between September 2016 and December 2017. This study provides evidence of the existence of statistically significant Plasmodium knowlesi malaria clusters in Sarawak, Malaysia. The analysis approach applied in this study showed potential in establishing surveillance and risk management system for knowlesi malaria control as Malaysia approaches human malaria elimination.
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Affiliation(s)
- Choo Huck Ooi
- Vector Borne Disease Section, Sarawak Health Department, Ministry of Health Malaysia, Kuching, Malaysia;,Address correspondence to Choo Huck Ooi, Vector Borne Disease Section, Sarawak Health Department, Ministry of Health Malaysia, Diplomatik Rd., Off Bako Rd., Kuching 93050, Malaysia, E-mail: or Yee Ling Lau, Department of Parasitology, Faculty of Medicine, University of Malaya, Jalan Profesor Diraja Ungku Aziz, Kuala Lumpur 50603, Malaysia, E-mail:
| | - Wei Kit Phang
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jonathan Wee Kent Liew
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,Address correspondence to Choo Huck Ooi, Vector Borne Disease Section, Sarawak Health Department, Ministry of Health Malaysia, Diplomatik Rd., Off Bako Rd., Kuching 93050, Malaysia, E-mail: or Yee Ling Lau, Department of Parasitology, Faculty of Medicine, University of Malaya, Jalan Profesor Diraja Ungku Aziz, Kuala Lumpur 50603, Malaysia, E-mail:
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New vectors that are early feeders for Plasmodium knowlesi and other simian malaria parasites in Sarawak, Malaysian Borneo. Sci Rep 2021; 11:7739. [PMID: 33833272 PMCID: PMC8032675 DOI: 10.1038/s41598-021-86107-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 03/09/2021] [Indexed: 02/01/2023] Open
Abstract
Plasmodium knowlesi is the main cause of malaria in Sarawak, where studies on vectors of P. knowlesi have been conducted in only two districts. Anopheles balabacensis and An. donaldi were incriminated as vectors in Lawas and An. latens in Kapit. We studied a third location in Sarawak, Betong, where of 2169 mosquitoes collected over 36 days using human-landing catches, 169 (7.8%) were Anopheles spp. PCR and phylogenetic analyses identified P. knowlesi and/or P. cynomolgi, P. fieldi, P. inui, P. coatneyi and possibly novel Plasmodium spp. in salivary glands of An. latens and An. introlatus from the Leucosphyrus Group and in An. collessi and An. roperi from the Umbrosus Group. Phylogenetic analyses of cytochrome oxidase subunit I sequences indicated three P. knowlesi-positive An. introlatus had been misidentified morphologically as An. latens, while An. collessi and An. roperi could not be delineated using the region sequenced. Almost all vectors from the Leucosphyrus Group were biting after 1800 h but those belonging to the Umbrosus Group were also biting between 0700 and 1100 h. Our study incriminated new vectors of knowlesi malaria in Sarawak and underscores the importance of including entomological studies during the daytime to obtain a comprehensive understanding of the transmission dynamics of malaria.
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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] [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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Chin AZ, Maluda MCM, Jelip J, Jeffree MSB, Culleton R, Ahmed K. Malaria elimination in Malaysia and the rising threat of Plasmodium knowlesi. J Physiol Anthropol 2020; 39:36. [PMID: 33228775 PMCID: PMC7686722 DOI: 10.1186/s40101-020-00247-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 11/11/2020] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major public-health problem, with over 40% of the world’s population (more than 3.3 billion people) at risk from the disease. Malaysia has committed to eliminate indigenous human malaria transmission by 2020. The objective of this descriptive study is to understand the epidemiology of malaria in Malaysia from 2000 through 2018 and to highlight the threat posed by zoonotic malaria to the National Malaria Elimination Strategic Plan. Methods Malaria is a notifiable infection in Malaysia. The data used in this study were extracted from the Disease Control Division, Ministry of Health Malaysia, contributed by the hospitals and health clinics throughout Malaysia. The population data used in this study was extracted from the Department of Statistics Malaysia. Data analyses were performed using Microsoft Excel. Data used for mapping are available at EPSG:4326 WGS84 CRS (Coordinate Reference System). Shapefile was obtained from igismap. Mapping and plotting of the map were performed using QGIS. Results Between 2000 and 2007, human malaria contributed 100% of reported malaria and 18–46 deaths per year in Malaysia. Between 2008 and 2017, indigenous malaria cases decreased from 6071 to 85 (98.6% reduction), while during the same period, zoonotic Plasmodium knowlesi cases increased from 376 to 3614 cases (an 861% increase). The year 2018 marked the first year that Malaysia did not report any indigenous cases of malaria caused by human malaria parasites. However, there was an increasing trend of P. knowlesi cases, with a total of 4131 cases reported in that year. Although the increased incidence of P. knowlesi cases can be attributed to various factors including improved diagnostic capacity, reduction in human malaria cases, and increase in awareness of P. knowlesi, more than 50% of P. knowlesi cases were associated with agriculture and plantation activities, with a large remainder proportion linked to forest-related activities. Conclusions Malaysia has entered the elimination phase of malaria control. Zoonotic malaria, however, is increasing exponentially and becoming a significant public health problem. Improved inter-sectoral collaboration is required in order to develop a more integrated effort to control zoonotic malaria. Local political commitment and the provision of technical support from the World Health Organization will help to create focused and concerted efforts towards ensuring the success of the National Malaria Elimination Strategic Plan.
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Affiliation(s)
- Abraham Zefong Chin
- Department of Community and Family Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia
| | - Marilyn Charlene Montini Maluda
- Department of Community and Family Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia
| | - Jenarun Jelip
- Disease Control Division, Ministry of Health, 62590, Putrajaya, Selangor, Malaysia
| | - Muhammad Saffree Bin Jeffree
- Department of Community and Family Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia.,Borneo Medical and Health Research Centre, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia
| | - Richard Culleton
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan
| | - Kamruddin Ahmed
- Borneo Medical and Health Research Centre, Universiti Malaysia Sabah, 88400, Kota Kinabalu, Sabah, Malaysia. .,Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Jalan UMS, 88400, Kota Kinabalu, Sabah, Malaysia.
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25
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Scott J. Proposed Integrated Control of Zoonotic Plasmodium knowlesi in Southeast Asia Using Themes of One Health. Trop Med Infect Dis 2020; 5:E175. [PMID: 33233871 PMCID: PMC7709578 DOI: 10.3390/tropicalmed5040175] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/15/2020] [Accepted: 11/18/2020] [Indexed: 01/28/2023] Open
Abstract
Zoonotic malaria, Plasmodium knowlesi, threatens the global progression of malaria elimination. Southeast Asian regions are fronting increased zoonotic malaria rates despite the control measures currently implemented-conventional measures to control human-malaria neglect P. knowlesi's residual transmission between the natural macaque host and vector. Initiatives to control P. knowlesi should adopt themes of the One Health approach, which details that the management of an infectious disease agent should be scrutinized at the human-animal-ecosystem interface. This review describes factors that have conceivably permitted the emergence and increased transmission rates of P. knowlesi to humans, from the understanding of genetic exchange events between subpopulations of P. knowlesi to the downstream effects of environmental disruption and simian and vector behavioral adaptations. These factors are considered to advise an integrative control strategy that aligns with the One Health approach. It is proposed that surveillance systems address the geographical distribution and transmission clusters of P. knowlesi and enforce ecological regulations that limit forest conversion and promote ecosystem regeneration. Furthermore, combining individual protective measures, mosquito-based feeding trapping tools and biocontrol strategies in synergy with current control methods may reduce mosquito population density or transmission capacity.
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Affiliation(s)
- Jessica Scott
- College of Public Health and Medical and Veterinary Sciences, Australian Institute of Tropical Health and Medicine, James Cook University, Townsville 4811, Australia
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26
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New vectors in northern Sarawak, Malaysian Borneo, for the zoonotic malaria parasite, Plasmodium knowlesi. Parasit Vectors 2020; 13:472. [PMID: 32933567 PMCID: PMC7490903 DOI: 10.1186/s13071-020-04345-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 09/05/2020] [Indexed: 11/19/2022] Open
Abstract
Background Plasmodium knowlesi is a significant cause of human malaria in Sarawak, Malaysian Borneo. Only one study has been previously undertaken in Sarawak to identify vectors of P. knowlesi, where Anopheles latens was incriminated as the vector in Kapit, central Sarawak. A study was therefore undertaken to identify malaria vectors in a different location in Sarawak. Methods Mosquitoes found landing on humans and resting on leaves over a 5-day period at two sites in the Lawas District of northern Sarawak were collected and identified. DNA samples extracted from salivary glands of Anopheles mosquitoes were subjected to nested PCR malaria-detection assays. The small subunit ribosomal RNA (SSU rRNA) gene of Plasmodium was sequenced, and the internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of the mosquitoes were sequenced from the Plasmodium-positive samples for phylogenetic analysis. Results Totals of 65 anophelines and 127 culicines were collected. By PCR, 6 An. balabacensis and 5 An. donaldi were found to have single P. knowlesi infections while 3 other An. balabacensis had either single, double or triple infections with P. inui, P. fieldi, P. cynomolgi and P. knowlesi. Phylogenetic analysis of the Plasmodium SSU rRNA gene confirmed 3 An. donaldi and 3 An. balabacensis with single P. knowlesi infections, while 3 other An. balabacensis had two or more Plasmodium species of P. inui, P. knowlesi, P. cynomolgi and some species of Plasmodium that could not be conclusively identified. Phylogenies inferred from the ITS2 and/or cox1 sequences of An. balabacensis and An. donaldi indicate that they are genetically indistinguishable from An. balabacensis and An. donaldi, respectively, found in Sabah, Malaysian Borneo. Conclusions Previously An. latens was identified as the vector for P. knowlesi in Kapit, central Sarawak, Malaysian Borneo, and now An. balabacensis and An. donaldi have been incriminated as vectors for zoonotic malaria in Lawas, northern Sarawak. ![]()
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Vidhya PT, Sunish IP, Maile A, Zahid AK. Anopheles sundaicus Mosquitoes as Vector for Plasmodium knowlesi, Andaman and Nicobar Islands, India. Emerg Infect Dis 2019; 25:817-820. [PMID: 30882328 PMCID: PMC6433020 DOI: 10.3201/eid2504.181668] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Using PCR and sequencing, we found Plasmodium knowlesi in the malaria vector Anopheles sundaicus mosquito collected from Katchal Island in the Andaman and Nicobar Islands, India. We cannot rule out natural transmission of this parasite to humans through this mosquito species. An in-depth investigation is needed to prevent disease outbreaks.
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Chua TH, Manin BO, Vythilingam I, Fornace K, Drakeley CJ. Effect of different habitat types on abundance and biting times of Anopheles balabacensis Baisas (Diptera: Culicidae) in Kudat district of Sabah, Malaysia. Parasit Vectors 2019; 12:364. [PMID: 31345256 PMCID: PMC6659233 DOI: 10.1186/s13071-019-3627-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/19/2019] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND We investigated the effect of five common habitat types on the diversity and abundance of Anopheles spp. and on the biting rate and time of Anopheles balabacensis (currently the only known vector for Plasmodium knowlesi in Sabah) at Paradason village, Kudat, Sabah. The habitats were forest edge, playground area, longhouse, oil palm plantation and shrub-bushes area. Sampling of Anopheles was done monthly using the human landing catch method in all habitat types for 14 months (October 2013 to December 2014, excluding June 2014). The Anopheles species were morphologically identified and subjected to PCR assay for the detection of Plasmodium parasites. Generalised linear mixed models (GLMM) were applied to test the variation in abundance and biting rates of An. balabacensis in different habitat types. RESULTS A total of 1599 Anopheles specimens were collected in the village, of which about 90% were An. balabacensis. Anopheles balabacensis was present throughout the year and was the dominant Anopheles species in all habitat types. The shrub bushes habitat had the highest Anopheles species diversity while forest edge had the greatest number of Anopheles individuals caught. GLMM analysis indicated that An. balabacensis abundance was not affected by the type of habitats, and it was more active during the early and late night compared to predawn and dawn. PCR assay showed that 1.61% of the tested An. balabacensis were positive for malaria parasites, most of which were caught in oil palm estates and infected with one to two Plasmodium species. CONCLUSIONS The identification of infected vectors in a range of habitats, including agricultural and farming areas, illustrates the potential for humans to be exposed to P. knowlesi outside forested areas. This finding contributes to a growing body of evidence implicating environmental changes due to deforestation, expansion of agricultural and farming areas, and development of human settlements near to forest fringes in the emergence of P. knowlesi in Sabah.
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Affiliation(s)
- Tock H Chua
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia.
| | - Benny O Manin
- 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
| | - Kimberly Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris J Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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Benavente ED, Gomes AR, De Silva JR, Grigg M, Walker H, Barber BE, William T, Yeo TW, de Sessions PF, Ramaprasad A, Ibrahim A, Charleston J, Hibberd ML, Pain A, Moon RW, Auburn S, Ling LY, Anstey NM, Clark TG, Campino S. Whole genome sequencing of amplified Plasmodium knowlesi DNA from unprocessed blood reveals genetic exchange events between Malaysian Peninsular and Borneo subpopulations. Sci Rep 2019; 9:9873. [PMID: 31285495 PMCID: PMC6614422 DOI: 10.1038/s41598-019-46398-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 06/28/2019] [Indexed: 12/19/2022] Open
Abstract
The zoonotic Plasmodium knowlesi parasite is the most common cause of human malaria in Malaysia. Genetic analysis has shown that the parasites are divided into three subpopulations according to their geographic origin (Peninsular or Borneo) and, in Borneo, their macaque host (Macaca fascicularis or M. nemestrina). Whilst evidence suggests that genetic exchange events have occurred between the two Borneo subpopulations, the picture is unclear in less studied Peninsular strains. One difficulty is that P. knowlesi infected individuals tend to present with low parasitaemia leading to samples with insufficient DNA for whole genome sequencing. Here, using a parasite selective whole genome amplification approach on unprocessed blood samples, we were able to analyse recent genomes sourced from both Peninsular Malaysia and Borneo. The analysis provides evidence that recombination events are present in the Peninsular Malaysia parasite subpopulation, which have acquired fragments of the M. nemestrina associated subpopulation genotype, including the DBPβ and NBPXa erythrocyte invasion genes. The NBPXb invasion gene has also been exchanged within the macaque host-associated subpopulations of Malaysian Borneo. Our work provides strong evidence that exchange events are far more ubiquitous than expected and should be taken into consideration when studying the highly complex P. knowlesi population structure.
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Affiliation(s)
- Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ana Rita Gomes
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.,Centre Hospitalier Universitaire de Montpellier, Montpellier, France
| | | | - Matthew Grigg
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Harriet Walker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Bridget E Barber
- Global 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, 88300, Kota Kinabalu, Sabah, Malaysia
| | - Timothy William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, 88300, Kota Kinabalu, Sabah, Malaysia.,Clinical Research Centre, Queen Elizabeth Hospital, 88300, Kota Kinabalu, Sabah, Malaysia.,Jesselton Medical Centre, 88300, Kota Kinabalu, Sabah, Malaysia
| | - Tsin Wen Yeo
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | | | - Abhinay Ramaprasad
- King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Amy Ibrahim
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - James Charleston
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Martin L Hibberd
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.,Genomics Institute, Biopolis, Singapore
| | - Arnab Pain
- King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Robert W Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sarah Auburn
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | | | - Nicholas M Anstey
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom. .,Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom.
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
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30
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Fong MY, Lau YL, Jelip J, Ooi CH, Cheong FW. Genetic characterisation of the erythrocyte-binding protein ($$\hbox {Pk}{\upbeta }\hbox {II}$$) of Plasmodium knowlesi isolates from Malaysia. J Genet 2019. [DOI: 10.1007/s12041-019-1109-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Lam-Phua SG, Yeo H, Lee RML, Chong CS, Png AB, Foo SY, Liew C, Ng LC, Tang CS, Rueda LM, Pecor JE, Harrison BA. Mosquitoes (Diptera: Culicidae) of Singapore: Updated Checklist and New Records. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:103-119. [PMID: 30169704 PMCID: PMC6324193 DOI: 10.1093/jme/tjy154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Indexed: 05/16/2023]
Abstract
Prior to 1965, Singapore was part of the Malaya (now Malaysia) and was usually not mentioned when mosquito records were reported for Malaya. Consequently, many species that occurred in Singapore were not listed in the world mosquito catalog, and the available checklist for Singapore since 1986 is incomplete, with some imprecise species information. In updating this checklist, we examined and verified mosquito specimens collected from Singapore in various depositories, including a thorough review of past taxonomic literature. Here, we report a checklist of 182 mosquito species, 33 new distribution records, and a consolidated status list of vectors for Singapore. As Singapore is a travel hub and hosts one of the busiest container ports in the world, there is a risk of introducing mosquito species and their associated pathogens of human disease to the country. Hence, the distribution records are important to increase our knowledge on mosquito ecology as well as to understand the risk of newly introduced vectors and their associated pathogens.
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Affiliation(s)
- Sai-Gek Lam-Phua
- Environmental Health Institute, National Environment Agency, Singapore
| | - Huiqing Yeo
- Environmental Health Institute, National Environment Agency, Singapore
| | - Ruth Mee-Lian Lee
- Environmental Health Institute, National Environment Agency, Singapore
| | - Chee-Seng Chong
- Environmental Health Institute, National Environment Agency, Singapore
| | - Ah-Bah Png
- Environmental Health Institute, National Environment Agency, Singapore
| | - Siew-Yoong Foo
- Environmental Health Institute, National Environment Agency, Singapore
| | - Christina Liew
- Environmental Health Institute, National Environment Agency, Singapore
| | - Lee-Ching Ng
- Environmental Health Institute, National Environment Agency, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Choon-Siang Tang
- Environmental Public Health Operations, National Environment Agency, Singapore
| | - Leopoldo M Rueda
- Department of Entomology, Walter Reed Biosystematics Unit, Smithsonian Institution, Museum Support Center (MRC534), Suitland, MD
| | - James E Pecor
- Department of Entomology, Walter Reed Biosystematics Unit, Smithsonian Institution, Museum Support Center (MRC534), Suitland, MD
| | - Bruce A Harrison
- Department of Entomology, Walter Reed Biosystematics Unit, Smithsonian Institution, Museum Support Center (MRC534), Suitland, MD
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Pongvongsa T, Culleton R, Ha H, Thanh L, Phongmany P, Marchand RP, Kawai S, Moji K, Nakazawa S, Maeno Y. Human infection with Plasmodium knowlesi on the Laos-Vietnam border. Trop Med Health 2018; 46:33. [PMID: 30250398 PMCID: PMC6145087 DOI: 10.1186/s41182-018-0116-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 09/10/2018] [Indexed: 09/03/2023] Open
Abstract
Background Border malaria in the Greater Mekong region of Southeast Asia poses a serious threat to the health of the ethnic minority populations of the region. Traditionally thought to be caused primarily by the malaria parasites Plasmodium falciparum and Plasmodium vivax, recently a zoonotic parasite, Plasmodium knowlesi, has been identified in some countries of the region. The presence of this parasite poses a challenge to malaria control programmes, as it is maintained in a zoonotic reservoir of forest-dwelling macaque monkeys. Methods A cross-sectional malaria parasite species prevalence survey was conducted along the Laos-Vietnam border in the central part of the two countries. Human blood samples were collected from Savannakhet in Laos and Quang Tri in Vietnam between August and October 2010 and assayed for the presence of human malaria parasite species and P. knowlesi. A PCR targeting the 18S small subunit ribosomal RNA gene and circumsporozoite protein gene was used for Plasmodium species identification. Results Nine cases of P. knowlesi were detected by PCR in blood samples from the Laos side and three from the Vietnam side. All P. knowlesi infections were found in co-infection with P. vivax, with some triple infections of P. knowlesi, P. vivax and P. falciparum detected in Laos. Phylogenetic analysis of these parasites suggests that P. knowlesi is circulating in the Laos-Vietnam border region. Conclusion This report shows that P. knowlesi is transmited on both sides of the Vietnam-Laos border. Continued monitoring of the range and prevalence of P. knowlesi on both the sides of Laos-Vietnam border is of importance to the National Malaria Control Programmes of both countries. Electronic supplementary material The online version of this article (10.1186/s41182-018-0116-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Richard Culleton
- 2Malaria Unit, Department of Pathology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Nagasaki Japan
| | - Hoang Ha
- Faculty of Public Health, Da Nang University of Medical Technology and Pharmacy, Da Nang, Vietnam
| | - Le Thanh
- Malaria-Parasitology and Entomology Department, Preventive Medicine Center of Quang Tri province, Quang Tri province, Vietnam
| | | | - Ron P Marchand
- Khanh Phu Malaria Research Unit, Medical Committee Netherlands-Viet Nam, Nha Trang, Khanh Hoa Province Vietnam
| | - Satoru Kawai
- 6Laboratory of Tropical Medicine and Parasitology, Dokkyo Medical University, Mibu, Tochigi, Japan
| | - Kazuhiko Moji
- 7Graduate School of Tropical Medicine & Global Health, Nagasaki University, Nagasaki, Nagasaki Japan
| | - Shusuke Nakazawa
- 8Department of Protozoology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Nagasaki Japan
| | - Yoshimasa Maeno
- 9Department of Virology and Parasitology, Fujita Health University School of Medicine, 1-98 Kutsukake, Toyoake, Aichi 470-1192 Japan
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Manin BO, Drakeley CJ, Chua TH. Mitochondrial variation in subpopulations of Anopheles balabacensis Baisas in Sabah, Malaysia (Diptera: Culicidae). PLoS One 2018; 13:e0202905. [PMID: 30138386 PMCID: PMC6107281 DOI: 10.1371/journal.pone.0202905] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 08/10/2018] [Indexed: 11/19/2022] Open
Abstract
Anopheles balabacensis, the primary vector of Plasmodium knowlesi in Sabah, Malaysia, is both zoophilic and anthropophilic, feeding on macaques as well as humans. It is the dominant Anopheles species found in Kudat Division where it is responsible for all the cases of P. knowlesi. However there is a paucity of basic biological and ecological information on this vector. We investigated the genetic variation of this species using the sequences of cox1 (1,383 bp) and cox2 (685 bp) to gain an insight into the population genetics and inter-population gene flow in Sabah. A total of 71 An. balabacensis were collected from seven districts constituting 14 subpopulations. A total of 17, 10 and 25 haplotypes were detected in the subpopulations respectively using the cox1, cox2 and the combined sequence. Some of the haplotypes were common among the subpopulations due to gene flow occurring between them. AMOVA showed that the genetic variation was high within subpopulations as compared to between subpopulations. Mantel test results showed that the variation between subpopulations was not due to the geographical distance between them. Furthermore, Tajima's D and Fu's Fs tests showed that An. balabacensis in Sabah is experiencing population expansion and growth. High gene flow between the subpopulations was indicated by the low genetic distance and high gene diversity in the cox1, cox2 and the combined sequence. However the population at Lipasu Lama appeared to be isolated possibly due to its higher altitude at 873 m above sea level.
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Affiliation(s)
- Benny Obrain Manin
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Chris J. Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Tock H. Chua
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- * E-mail:
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Amir A, Cheong FW, de Silva JR, Liew JWK, Lau YL. Plasmodium knowlesi malaria: current research perspectives. Infect Drug Resist 2018; 11:1145-1155. [PMID: 30127631 PMCID: PMC6089103 DOI: 10.2147/idr.s148664] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Originally known to cause simian malaria, Plasmodium knowlesi is now known as the fifth human malaria species. Since the publishing of a report that largely focused on human knowlesi cases in Sarawak in 2004, many more human cases have been reported in nearly all of the countries in Southeast Asia and in travelers returning from these countries. The zoonotic nature of this infection hinders malaria elimination efforts. In order to grasp the current perspective of knowlesi malaria, this literature review explores the different aspects of the disease including risk factors, diagnosis, treatment, and molecular and functional studies. Current studies do not provide sufficient data for an effective control program. Therefore, future direction for knowlesi research is highlighted here with a final aim of controlling, if not eliminating, the parasite.
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Affiliation(s)
- Amirah Amir
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
| | - Fei Wen Cheong
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
| | - Jeremy Ryan de Silva
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
| | - Jonathan Wee Kent Liew
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,
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Fornace KM, Herman LS, Abidin TR, Chua TH, Daim S, Lorenzo PJ, Grignard L, Nuin NA, Ying LT, Grigg MJ, William T, Espino F, Cox J, Tetteh KKA, Drakeley CJ. Exposure and infection to Plasmodium knowlesi in case study communities in Northern Sabah, Malaysia and Palawan, The Philippines. PLoS Negl Trop Dis 2018; 12:e0006432. [PMID: 29902171 PMCID: PMC6001952 DOI: 10.1371/journal.pntd.0006432] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/05/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Primarily impacting poor, rural populations, the zoonotic malaria Plasmodium knowlesi is now the main cause of human malaria within Malaysian Borneo. While data is increasingly available on symptomatic cases, little is known about community-level patterns of exposure and infection. Understanding the true burden of disease and associated risk factors within endemic communities is critical for informing evidence-based control measures. METHODOLOGY/PRINCIPAL FINDINGS We conducted comprehensive surveys in three areas where P. knowlesi transmission is reported: Limbuak, Pulau Banggi and Matunggung, Kudat, Sabah, Malaysia and Bacungan, Palawan, the Philippines. Infection prevalence was low with parasites detected by PCR in only 0.2% (4/2503) of the population. P. knowlesi PkSERA3 ag1 antibody responses were detected in 7.1% (95% CI: 6.2-8.2%) of the population, compared with 16.1% (14.6-17.7%) and 12.6% (11.2-14.1%) for P. falciparum and P. vivax. Sero-prevalence was low in individuals <10 years old for P. falciparum and P. vivax consistent with decreased transmission of non-zoonotic malaria species. Results indicated marked heterogeneity in transmission intensity between sites and P. knowlesi exposure was associated with agricultural work (OR 1.63; 95% CI 1.07-2.48) and higher levels of forest cover (OR 2.40; 95% CI 1.29-4.46) and clearing (OR 2.14; 95% CI 1.35-3.40) around houses. Spatial patterns of P. knowlesi exposure differed from exposure to non-zoonotic malaria and P. knowlesi exposed individuals were younger on average than individuals exposed to non-zoonotic malaria. CONCLUSIONS/SIGNIFICANCE This is the first study to describe serological exposure to P. knowlesi and associated risk factors within endemic communities. Results indicate community-level patterns of infection and exposure differ markedly from demographics of reported cases, with higher levels of exposure among women and children. Further work is needed to understand these variations in risk across a wider population and spatial scale.
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Affiliation(s)
- Kimberly M. Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Lou S. Herman
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Tommy R. Abidin
- Infectious Diseases Society Kota Kinabalu- Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Malaysia
| | - Tock Hing Chua
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Sylvia Daim
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Pauline J. Lorenzo
- Research Institute of Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | - Lynn Grignard
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Nor Afizah Nuin
- Biotechnology Research Institute, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Lau Tiek Ying
- Biotechnology Research Institute, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Matthew J. Grigg
- Infectious Diseases Society Kota Kinabalu- Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Malaysia
- Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Timothy William
- Infectious Diseases Society Kota Kinabalu- Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Malaysia
- Jesselton Medical Centre, Kota Kinabalu, Malaysia
| | - Fe Espino
- Research Institute of Tropical Medicine, Department of Health, Muntinlupa City, Philippines
| | - Jonathan Cox
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kevin K. A. Tetteh
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Chris J. Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Ooi CH, Bujang MA, Tg Abu Bakar Sidik TMI, Ngui R, Lim YAL. Over two decades of Plasmodium knowlesi infections in Sarawak: Trend and forecast. Acta Trop 2017; 176:83-90. [PMID: 28768148 DOI: 10.1016/j.actatropica.2017.07.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 06/10/2017] [Accepted: 07/24/2017] [Indexed: 02/01/2023]
Abstract
Malaria is still of great public health concern, especially in Malaysian Borneo. The aim of this study was to determine the trends of P. knowlesi infection in Sarawak, Malaysia and to forecast the incidence of P. knowlesi until the year 2040. Data on P. knowlesi malaria cases from 1992 to the year 2014 were obtained from the Sarawak Health Department, Malaysia. ARIMA model was applied to forecast the future incidence of P. knowlesi infection. The data for the whole of Sarawak and subsequently the selected six districts which have high incidence rates of P. knowlesi infection were analyzed. Results of the analysis showed that there was an increasing trend of P. knowlesi cases from the year 1992-2014 (p<0.001). The trend in the incidence started to increase in the year 2008 (p=0.029). The incidence rate per 100,000 populations was between 4.15 in the year 1992 and 42.03 in the year 2014. High incidence of P. knowlesi infections has been detected in the districts adjacent to each other within the interior region of Sarawak. The forecasted incidence and incidence rate per 100,000 populations in the year 2020 were 1229 and 44.04, respectively, while those in the year 2040 were 2056 and 62.91, respectively. The forecasted incidence showed an upward trend highlighting an urgent need to draw up strategic and holistic prevention plans to limit further the increase in P. knowlesi morbidity and mortality in Sarawak. It is imperative that these measures are customized taking into consideration the challenges faced in the interior areas of Sarawak and the behavior of the main vector of P. knowlesi (i.e., An. latens) in Sarawak.
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Chua TH, Manin BO, Daim S, Vythilingam I, Drakeley C. Phylogenetic analysis of simian Plasmodium spp. infecting Anopheles balabacensis Baisas in Sabah, Malaysia. PLoS Negl Trop Dis 2017; 11:e0005991. [PMID: 28968395 PMCID: PMC5638607 DOI: 10.1371/journal.pntd.0005991] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/12/2017] [Accepted: 09/24/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Anopheles balabacensis of the Leucospyrus group has been confirmed as the primary knowlesi malaria vector in Sabah, Malaysian Borneo for some time now. Presently, knowlesi malaria is the only zoonotic simian malaria in Malaysia with a high prevalence recorded in the states of Sabah and Sarawak. METHODOLOGY/PRINCIPAL FINDINGS Anopheles spp. were sampled using human landing catch (HLC) method at Paradason village in Kudat district of Sabah. The collected Anopheles were identified morphologically and then subjected to total DNA extraction and polymerase chain reaction (PCR) to detect Plasmodium parasites in the mosquitoes. Identification of Plasmodium spp. was confirmed by sequencing the SSU rRNA gene with species specific primers. MEGA4 software was then used to analyse the SSU rRNA sequences and bulid the phylogenetic tree for inferring the relationship between simian malaria parasites in Sabah. PCR results showed that only 1.61% (23/1,425) of the screened An. balabacensis were infected with one or two of the five simian Plasmodium spp. found in Sabah, viz. Plasmodium coatneyi, P. inui, P. fieldi, P. cynomolgi and P. knowlesi. Sequence analysis of SSU rRNA of Plasmodium isolates showed high percentage of identity within the same Plasmodium sp. group. The phylogenetic tree based on the consensus sequences of P. knowlesi showed 99.7%-100.0% nucleotide identity among the isolates from An. balabacensis, human patients and a long-tailed macaque from the same locality. CONCLUSIONS/SIGNIFICANCE This is the first study showing high molecular identity between the P. knowlesi isolates from An. balabacensis, human patients and a long-tailed macaque in Sabah. The other common simian Plasmodium spp. found in long-tailed macaques and also detected in An. balabacensis were P. coatneyi, P. inui, P. fieldi and P. cynomolgi. The high percentage identity of nucleotide sequences between the P. knowlesi isolates from the long-tailed macaque, An. balabacensis and human patients suggests a close genetic relationship between the parasites from these hosts.
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Affiliation(s)
- Tock H. Chua
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Benny O. Manin
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Sylvia Daim
- 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
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Diez Benavente E, Florez de Sessions P, Moon RW, Holder AA, Blackman MJ, Roper C, Drakeley CJ, Pain A, Sutherland CJ, Hibberd ML, Campino S, Clark TG. Analysis of nuclear and organellar genomes of Plasmodium knowlesi in humans reveals ancient population structure and recent recombination among host-specific subpopulations. PLoS Genet 2017; 13:e1007008. [PMID: 28922357 PMCID: PMC5619863 DOI: 10.1371/journal.pgen.1007008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/28/2017] [Accepted: 09/07/2017] [Indexed: 12/28/2022] Open
Abstract
The macaque parasite Plasmodium knowlesi is a significant concern in Malaysia where cases of human infection are increasing. Parasites infecting humans originate from genetically distinct subpopulations associated with the long-tailed (Macaca fascicularis (Mf)) or pig-tailed macaques (Macaca nemestrina (Mn)). We used a new high-quality reference genome to re-evaluate previously described subpopulations among human and macaque isolates from Malaysian-Borneo and Peninsular-Malaysia. Nuclear genomes were dimorphic, as expected, but new evidence of chromosomal-segment exchanges between subpopulations was found. A large segment on chromosome 8 originating from the Mn subpopulation and containing genes encoding proteins expressed in mosquito-borne parasite stages, was found in Mf genotypes. By contrast, non-recombining organelle genomes partitioned into 3 deeply branched lineages, unlinked with nuclear genomic dimorphism. Subpopulations which diverged in isolation have re-connected, possibly due to deforestation and disruption of wild macaque habitats. The resulting genomic mosaics reveal traits selected by host-vector-parasite interactions in a setting of ecological transition.
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Affiliation(s)
- Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Robert W. Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Michael J. Blackman
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
| | - Cally Roper
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher J. Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Arnab Pain
- King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Colin J. Sutherland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Martin L. Hibberd
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Genome Institute of Singapore, Biopolis, Singapore
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Taane G. Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Multiple Ecological Factors Influence the Location of Proboscis Monkey (Nasalis larvatus) Sleeping Sites in West Kalimantan, Indonesia. INT J PRIMATOL 2017. [DOI: 10.1007/s10764-017-9953-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
Plasmodium knowlesi is increasingly recognized as a major cause of malaria in Southeast Asia. Anopheles leucosphyrous group mosquitoes transmit the parasite and natural hosts include long-tailed and pig-tailed macaques. Despite early laboratory experiments demonstrating successful passage of infection between humans, the true role that humans play in P. knowlesi epidemiology remains unclear. The threat posed by its introduction into immunologically naïve populations is unknown despite being a public health priority for this region. A two-host species mathematical model was constructed to analyse this threat. Global sensitivity analysis using Monte Carlo methods highlighted the biological processes of greatest influence to transmission. These included parameters known to be influential in classic mosquito-borne disease models (e.g. vector longevity); however, interesting ecological components that are specific to this system were also highlighted: while local vectors likely have intrinsic preferences for certain host species, how plastic these preferences are, and how this is shaped by local conditions, are key determinants of parasite transmission potential. Invasion analysis demonstrates that this behavioural plasticity can qualitatively impact the probability of an epidemic sparked by imported infection. Identifying key vector sub/species and studying their biting behaviours constitute important next steps before models can better assist in strategizing disease control.
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Abstract
The primate malaria Plasmodium knowlesi has a long-standing history as an experimental malaria model. Studies using this model parasite in combination with its various natural and experimental non-human primate hosts have led to important advances in vaccine development and in our understanding of malaria invasion, immunology and parasite-host interactions. The adaptation to long-term in vitro continuous blood stage culture in rhesus monkey, Macaca fascicularis and human red blood cells, as well as the development of various transfection methodologies has resulted in a highly versatile experimental malaria model, further increasing the potential of what was already a very powerful model. The growing evidence that P. knowlesi is an important human zoonosis in South-East Asia has added relevance to former and future studies of this parasite species.
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Manin BO, Ferguson HM, Vythilingam I, Fornace K, William T, Torr SJ, Drakeley C, Chua TH. Investigating the Contribution of Peri-domestic Transmission to Risk of Zoonotic Malaria Infection in Humans. PLoS Negl Trop Dis 2016; 10:e0005064. [PMID: 27741235 PMCID: PMC5065189 DOI: 10.1371/journal.pntd.0005064] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/21/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In recent years, the primate malaria Plasmodium knowlesi has emerged in human populations throughout South East Asia, with the largest hotspot being in Sabah, Malaysian Borneo. Control efforts are hindered by limited knowledge of where and when people get exposed to mosquito vectors. It is assumed that exposure occurs primarily when people are working in forest areas, but the role of other potential exposure routes (including domestic or peri-domestic transmission) has not been thoroughly investigated. METHODOLOGY/PRINCIPAL FINDINGS We integrated entomological surveillance within a comprehensive case-control study occurring within a large hotspot of transmission in Sabah, Malaysia. Mosquitoes were collected at 28 pairs households composed of one where an occupant had a confirmed P. knowlesi infection within the preceding 3 weeks ("case") and an associated "control" where no infection was reported. Human landing catches were conducted to measure the number and diversity of mosquitoes host seeking inside houses and in the surrounding peri-domestic (outdoors but around the household) areas. The predominant malaria vector species was Anopheles balabacensis, most of which were caught outdoors in the early evening (6pm - 9pm). It was significantly more abundant in the peri-domestic area than inside houses (5.5-fold), and also higher at case than control households (0.28±0.194 vs 0.17±0.127, p<0.001). Ten out of 641 An. balabacensis tested were positive for simian malaria parasites, but none for P. knowlesi. CONCLUSIONS/SIGNIFICANCE This study shows there is a possibility that humans can be exposed to P. knowlesi infection around their homes. The vector is highly exophagic and few were caught indoors indicating interventions using bednets inside households may have relatively little impact.
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Affiliation(s)
- Benny O. Manin
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Heather M. Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, United Kingdom
| | - Indra Vythilingam
- Parasitology Department, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kim Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Steve J. Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, United Kingdom
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Tock H. Chua
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- * E-mail: ,
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Abstract
Plasmodium knowlesi a simian malaria parasite is currently affecting humans in Southeast Asia. Malaysia has reported the most number of cases and P. knowlesi is the predominant species occurring in humans. The vectors of P. knowlesi belong to the Leucosphyrus group of Anopheles mosquitoes. These are generally described as forest-dwelling mosquitoes. With deforestation and changes in land-use, some species have become predominant in farms and villages. However, knowledge on the distribution of these vectors in the country is sparse. From a public health point of view it is important to know the vectors, so that risk factors towards knowlesi malaria can be identified and control measures instituted where possible. Here, we review what is known about the knowlesi malaria vectors and ascertain the gaps in knowledge, so that future studies could concentrate on this paucity of data in-order to address this zoonotic problem.
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Fong MY, Rashdi SAA, Yusof R, Lau YL. Genetic Diversity, Natural Selection and Haplotype Grouping of Plasmodium knowlesi Gamma Protein Region II (PkγRII): Comparison with the Duffy Binding Protein (PkDBPαRII). PLoS One 2016; 11:e0155627. [PMID: 27195821 PMCID: PMC4873119 DOI: 10.1371/journal.pone.0155627] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/01/2016] [Indexed: 02/03/2023] Open
Abstract
Background Plasmodium knowlesi is a simian malaria parasite that has been reported to cause malaria in humans in Southeast Asia. This parasite invades the erythrocytes of humans and of its natural host, the macaque Macaca fascicularis, via interaction between the Duffy binding protein region II (PkDBPαRII) and the Duffy antigen receptor on the host erythrocytes. In contrast, the P. knowlesi gamma protein region II (PkγRII) is not involved in the invasion of P. knowlesi into humans. PkγRII, however, mediates the invasion of P. knowlesi into the erythrocytes of M. mulata, a non-natural host of P. knowlesi via a hitherto unknown receptor. The haplotypes of PkDBPαRII in P. knowlesi isolates from Peninsular Malaysia and North Borneo have been shown to be genetically distinct and geographically clustered. Also, the PkDBPαRII was observed to be undergoing purifying (negative) selection. The present study aimed to determine whether similar phenomena occur in PkγRII. Methods Blood samples from 78 knowlesi malaria patients were used. Forty-eight of the samples were from Peninsular Malaysia, and 30 were from Malaysia Borneo. The genomic DNA of the samples was extracted and used as template for the PCR amplification of the PkγRII. The PCR product was cloned and sequenced. The sequences obtained were analysed for genetic diversity and natural selection using MEGA6 and DnaSP (version 5.10.00) programmes. Genetic differentiation between the PkγRII of Peninsular Malaysia and North Borneo isolates was estimated using the Wright’s FST fixation index in DnaSP (version 5.10.00). Haplotype analysis was carried out using the Median-Joining approach in NETWORK (version 4.6.1.3). Results A total of 78 PkγRII sequences was obtained. Comparative analysis showed that the PkγRII have similar range of haplotype (Hd) and nucleotide diversity (π) with that of PkDBPαRII. Other similarities between PkγRII and PkDBPαRII include undergoing purifying (negative) selection, geographical clustering of haplotypes, and high inter-population genetic differentiation (FST index). The main differences between PkγRII and PkDBPαRII include length polymorphism and no departure from neutrality (as measured by Tajima’s D statistics) in the PkγRII. Conclusion Despite the biological difference between PkγRII and PkDBPαRII, both generally have similar genetic diversity level, natural selection, geographical haplotype clustering and inter-population genetic differentiation index.
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Affiliation(s)
- Mun Yik Fong
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail:
| | - Sarah A. A. Rashdi
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Ruhani Yusof
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Moyes CL, Shearer FM, Huang Z, Wiebe A, Gibson HS, Nijman V, Mohd-Azlan J, Brodie JF, Malaivijitnond S, Linkie M, Samejima H, O'Brien TG, Trainor CR, Hamada Y, Giordano AJ, Kinnaird MF, Elyazar IRF, Sinka ME, Vythilingam I, Bangs MJ, Pigott DM, Weiss DJ, Golding N, Hay SI. Predicting the geographical distributions of the macaque hosts and mosquito vectors of Plasmodium knowlesi malaria in forested and non-forested areas. Parasit Vectors 2016; 9:242. [PMID: 27125995 PMCID: PMC4850754 DOI: 10.1186/s13071-016-1527-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 04/21/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Plasmodium knowlesi is a zoonotic pathogen, transmitted among macaques and to humans by anopheline mosquitoes. Information on P. knowlesi malaria is lacking in most regions so the first step to understand the geographical distribution of disease risk is to define the distributions of the reservoir and vector species. METHODS We used macaque and mosquito species presence data, background data that captured sampling bias in the presence data, a boosted regression tree model and environmental datasets, including annual data for land classes, to predict the distributions of each vector and host species. We then compared the predicted distribution of each species with cover of each land class. RESULTS Fine-scale distribution maps were generated for three macaque host species (Macaca fascicularis, M. nemestrina and M. leonina) and two mosquito vector complexes (the Dirus Complex and the Leucosphyrus Complex). The Leucosphyrus Complex was predicted to occur in areas with disturbed, but not intact, forest cover (> 60% tree cover) whereas the Dirus Complex was predicted to occur in areas with 10-100% tree cover as well as vegetation mosaics and cropland. Of the macaque species, M. nemestrina was mainly predicted to occur in forested areas whereas M. fascicularis was predicted to occur in vegetation mosaics, cropland, wetland and urban areas in addition to forested areas. CONCLUSIONS The predicted M. fascicularis distribution encompassed a wide range of habitats where humans are found. This is of most significance in the northern part of its range where members of the Dirus Complex are the main P. knowlesi vectors because these mosquitoes were also predicted to occur in a wider range of habitats. Our results support the hypothesis that conversion of intact forest into disturbed forest (for example plantations or timber concessions), or the creation of vegetation mosaics, will increase the probability that members of the Leucosphyrus Complex occur at these locations, as well as bringing humans into these areas. An explicit analysis of disease risk itself using infection data is required to explore this further. The species distributions generated here can now be included in future analyses of P. knowlesi infection risk.
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Affiliation(s)
- Catherine L Moyes
- Spatial Ecology & Epidemiology Group, The Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7BN, UK.
| | - Freya M Shearer
- Spatial Ecology & Epidemiology Group, The Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7BN, UK
| | - Zhi Huang
- Spatial Ecology & Epidemiology Group, Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK
| | - Antoinette Wiebe
- Spatial Ecology & Epidemiology Group, The Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7BN, UK
| | - Harry S Gibson
- Spatial Ecology & Epidemiology Group, Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK
| | - Vincent Nijman
- Department of Social Sciences, Oxford Brookes University, Oxford, OX1 0BP, UK
| | - Jayasilan Mohd-Azlan
- Department of Zoology, Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia
| | - Jedediah F Brodie
- Departments of Zoology and Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Suchinda Malaivijitnond
- Primate Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Matthew Linkie
- Fauna & Flora International, Singapore, 247672, Singapore
| | - Hiromitsu Samejima
- Institute for Global Environmental Strategies, Kamiyamaguchi 2108-11, Hayama-cho, 240-0115, Kanagawa, Japan
| | - Timothy G O'Brien
- Wildlife Conservation Society, Mpala Research Center, Nanyuki, 10400, Kenya
| | - Colin R Trainor
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Northern Territory, 0909, Australia
- Faculty of Science and Technology, Federation University Australia, Mt Helen, Victoria, 3350, Australia
| | - Yuzuru Hamada
- Evolutionary Morphology Section, Primate Research Institute, Kyoto University, Inuyama, Japan
| | - Anthony J Giordano
- Field Conservation Program, S.P.E.C.I.E.S., Ventura, CA, USA
- Conservation Science Program, Tiger Creek Wildlife Refuge, Tyler, TX, USA
| | | | | | - Marianne E Sinka
- Spatial Ecology & Epidemiology Group, Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Michael J Bangs
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, 10900, Thailand
- Public Health and Malaria Control Department, International SOS, Jalan Kertajasa, Kuala Kencana, Papua, 99920, Indonesia
| | - David M Pigott
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, 98121, USA
| | - Daniel J Weiss
- Spatial Ecology & Epidemiology Group, Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK
| | - Nick Golding
- Spatial Ecology & Epidemiology Group, The Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7BN, UK
| | - Simon I Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, 98121, USA
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
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Mvumbi DM, Lengu Bobanga T, Umesumbu SE, Kunyu BS, Ntumba Kayembe JM, Situakibanza NTH, Mvumbi GL, Melin P, De Mol P, Hayette MP. Investigation on possible transmission of monkeys' Plasmodium to human in a populations living in the equatorial rainforest of the Democratic republic of Congo. Int J Parasitol Parasites Wildl 2016; 5:1-4. [PMID: 27141437 PMCID: PMC4840266 DOI: 10.1016/j.ijppaw.2015.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 11/19/2015] [Accepted: 11/26/2015] [Indexed: 01/01/2023]
Abstract
Plasmodiums are protozoa that may infect various hosts. Only five species are now recognized as naturally parasitizing humans: Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale and Plasmodium knowlesi. This fifth species, P. knowlesi, previously identified as naturally parasitizing the monkey Macaca fascicularis, has been microscopically confused for a long time with P. malariae or P. falciparum and it was not possible to correctly differentiate them until the advent of molecular biology. To date, natural human infections with P. knowlesi only occur in Southeast Asia and a similar phenomenon of natural transmission of simian plasmodium to humans has not been reported elsewhere. This study was conducted to investigate a possible transmission of African small monkey's plasmodium to humans in populations living near the rainforest of the Democratic Republic of Congo (DRC) where several species of non-human primates are living. Two successive real-time PCRs were identified in the literature and used in combination for purpose. Only P. falciparum was found in this study. However, studies with larger samples and with more advanced techniques should be conducted.
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Affiliation(s)
- Dieudonné Makaba Mvumbi
- Biochemistry and Molecular Biology Unit, Department of Basic Sciences, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Thierry Lengu Bobanga
- Department of Parasitology and Tropical Medicine, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | | | - Billy Shako Kunyu
- Department of Parasitology and Tropical Medicine, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Jean-Marie Ntumba Kayembe
- Department of Internal Medicine, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Nani-Tuma H. Situakibanza
- Department of Parasitology and Tropical Medicine, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
- Department of Internal Medicine, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Georges Lelo Mvumbi
- Biochemistry and Molecular Biology Unit, Department of Basic Sciences, School of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Pierrette Melin
- Department of Clinical Microbiology, University Hospital of Liège, Liège, Belgium
| | - Patrick De Mol
- Department of Clinical Microbiology, University Hospital of Liège, Liège, Belgium
| | - Marie-Pierre Hayette
- Department of Clinical Microbiology, University Hospital of Liège, Liège, Belgium
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BROCK PM, FORNACE KM, PARMITER M, COX J, DRAKELEY CJ, FERGUSON HM, KAO RR. Plasmodium knowlesi transmission: integrating quantitative approaches from epidemiology and ecology to understand malaria as a zoonosis. Parasitology 2016; 143:389-400. [PMID: 26817785 PMCID: PMC4800714 DOI: 10.1017/s0031182015001821] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/01/2015] [Accepted: 12/02/2015] [Indexed: 12/12/2022]
Abstract
The public health threat posed by zoonotic Plasmodium knowlesi appears to be growing: it is increasingly reported across South East Asia, and is the leading cause of malaria in Malaysian Borneo. Plasmodium knowlesi threatens progress towards malaria elimination as aspects of its transmission, such as spillover from wildlife reservoirs and reliance on outdoor-biting vectors, may limit the effectiveness of conventional methods of malaria control. The development of new quantitative approaches that address the ecological complexity of P. knowlesi, particularly through a focus on its primary reservoir hosts, will be required to control it. Here, we review what is known about P. knowlesi transmission, identify key knowledge gaps in the context of current approaches to transmission modelling, and discuss the integration of these approaches with clinical parasitology and geostatistical analysis. We highlight the need to incorporate the influences of fine-scale spatial variation, rapid changes to the landscape, and reservoir population and transmission dynamics. The proposed integrated approach would address the unique challenges posed by malaria as a zoonosis, aid the identification of transmission hotspots, provide insight into the mechanistic links between incidence and land use change and support the design of appropriate interventions.
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Affiliation(s)
- P. M. BROCK
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - K. M. FORNACE
- London School of Hygiene and Tropical Medicine, London, UK
| | - M. PARMITER
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - J. COX
- London School of Hygiene and Tropical Medicine, London, UK
| | - C. J. DRAKELEY
- London School of Hygiene and Tropical Medicine, London, UK
| | - H. M. FERGUSON
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - R. R. KAO
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Abstract
There were only four species of Plasmodium that were thought to cause malaria in humans until a large number of human infections by Plasmodium knowlesi, a malaria parasite typically found in long-tailed and pig-tailed macaques, were reported in 2004 in Malaysian Borneo. Since then, cases of knowlesi malaria have been reported throughout South-east Asia and also in travellers returning from the region. This article describes the molecular, entomological and epidemiological data which indicate that P. knowlesi is an ancient parasite that is primarily zoonotic, and there are three highly divergent sub-populations. It also describes the detection methods for P. knowlesi, which is morphologicaly similar to P. malariae, and the clinical features and treatment of this malaria parasite that is potentially fatal.
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Wong ML, Chua TH, Leong CS, Khaw LT, Fornace K, Wan-Sulaiman WY, William T, Drakeley C, Ferguson HM, Vythilingam I. Seasonal and Spatial Dynamics of the Primary Vector of Plasmodium knowlesi within a Major Transmission Focus in Sabah, Malaysia. PLoS Negl Trop Dis 2015; 9:e0004135. [PMID: 26448052 PMCID: PMC4598189 DOI: 10.1371/journal.pntd.0004135] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/10/2015] [Indexed: 11/18/2022] Open
Abstract
Background The simian malaria parasite Plasmodium knowlesi is emerging as a public health problem in Southeast Asia, particularly in Malaysian Borneo where it now accounts for the greatest burden of malaria cases and deaths. Control is hindered by limited understanding of the ecology of potential vector species. Methodology/Principal Findings We conducted a one year longitudinal study of P. knowlesi vectors in three sites within an endemic area of Sabah, Malaysia. All mosquitoes were captured using human landing catch. Anopheles mosquitoes were dissected to determine, oocyst, sporozoites and parous rate. Anopheles balabacensis is confirmed as the primary vector of. P. knowlesi (using nested PCR) in Sabah for the first time. Vector densities were significantly higher and more seasonally variable in the village than forest or small scale farming site. However An. balabacensis survival and P. knowlesi infection rates were highest in forest and small scale farm sites. Anopheles balabacensis mostly bites humans outdoors in the early evening between 1800 to 2000hrs. Conclusions/Significance This study indicates transmission is unlikely to be prevented by bednets. This combined with its high vectorial capacity poses a threat to malaria elimination programmes within the region. The first natural infection of Plasmodium knowlesi was reported 40 years ago. At that time it was perceived that the infection would not affect humans. However, now P. knowlesi is the predominant malaria species (38% of the cases) infecting people in Malaysia and is a notable obstacle to malaria elimination in the country. Plasmodium knowlesi has also been reported from all countries in Southeast Asia with the exception of Lao PDR and Timor Leste. In Sabah, Malaysian Borneo cases of human P. knowlesi are increasing. Thus, a comprehensive understanding of the bionomics of the vectors is required so as to enable proper control strategies. Here, we conducted a longitudinal study in Kudat district, Sabah, to determine and characterize the vectors of P. knowlesi within this transmission foci. Anopheles balabacensis was the predominant mosquito in all study sites and is confirmed as vector for P. knowlesi and other simian malaria parasites. The peak biting time was in the early part of the evening between1800 to 2000. Thus, breaking the chain of transmission is an extremely challenging task for the malaria elimination programme.
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Affiliation(s)
- Meng L. Wong
- Parasitology Department, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Tock H. Chua
- Department of Pathobiology and Medical Diagnostics, Faculty of Medicine and Health Sciences, Universiti Sabah Malaysia, Kota Kinabalu, Sabah, Malaysia
| | - Cherng S. Leong
- Parasitology Department, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Loke T. Khaw
- Parasitology Department, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kimberly Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Heather M. Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Scotland, United Kingdom
| | - Indra Vythilingam
- Parasitology Department, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail:
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Fong MY, Ahmed MA, Wong SS, Lau YL, Sitam F. Genetic Diversity and Natural Selection of the Plasmodium knowlesi Circumsporozoite Protein Nonrepeat Regions. PLoS One 2015; 10:e0137734. [PMID: 26379157 PMCID: PMC4575020 DOI: 10.1371/journal.pone.0137734] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 08/21/2015] [Indexed: 11/18/2022] Open
Abstract
Background Plasmodium knowlesi is a simian malaria parasite that has been identified to cause malaria in humans. To date, several thousand cases of human knowlesi malaria have been reported around Southeast Asia. Thus far, there is no detailed study on genetic diversity and natural selection of P. knowlesi circumsporozoite protein (CSP), a prominent surface antigen on the sporozoite of the parasite. In the present study, the genetic diversity and natural selection acting on the nonrepeat regions of the gene encoding P. knowlesi CSP were investigated, focusing on the T-cell epitope regions at the C-terminal of the protein. Methods Blood samples from 32 knowlesi malaria patients and 2 wild monkeys (Macaca fascicularis) were used. The CSP of the P. knowlesi isolates was amplified by PCR, cloned into Escherichia coli, and sequenced. The nonrepeat regions of the CSP gene were analysed for genetic diversity, natural selection and haplotypic grouping using MEGA5 and DnaSP version 5.10.00 programmes. A haplotype network was constructed based on the C-terminal (Th2R/Th3R) T-cell epitope regions using the Median-Joining method in the NETWORK version 4.6.1.2 programme. Previously published sequences from other regions (Malaysia Borneo, Singapore) were also included in the analysis. Results A total of 123 P. knowlesi CSP sequences were analysed. Multiple sequence alignment revealed 58 amino acid changes, and 42 novel amino acid haplotypes were identified. Polymorphism was higher in the C-terminal Th2R/Th3R epitope (π = 0.0293, n = 123) region compared to the overall combined nonrepeat regions (π = 0.0120, n = 123). Negative natural selection was observed within the nonrepeat regions of the CSP gene. Within the C-terminal Th2R/Th3R epitope regions, there was evidence of slight positive selection. Based on haplotype network analysis of the Th2R/Th3R regions, five abundant haplotypes were identified. Sharing of haplotypes between humans and macaques were observed. Conclusion This study contributes to the understanding of the type and distribution of naturally occurring polymorphism in the P. knowlesi CSP gene. This study also provides a measurement of the genetic diversity of P. knowlesi and identifies the predominant haplotypes within Malaysia based on the C-terminal Th2R/Th3R regions.
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Affiliation(s)
- Mun Yik Fong
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail:
| | - Md Atique Ahmed
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Shen Siang Wong
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Frankie Sitam
- Department of Wildlife and National Parks Peninsular Malaysia, Kuala Lumpur, Malaysia
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