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Chan TTY, Chow FWN, Fung J, Cheng FKK, Lo GCS, Tsang CC, Luk HKH, Wong ACP, He Z, Aw-Yong KL, Liu X, Yuen KY, Woo PCY, Lau SKP. A sensitive and simple RT-LAMP assay for sarbecovirus screening in bats. Microbiol Spectr 2023; 11:e0259123. [PMID: 37971222 PMCID: PMC10715088 DOI: 10.1128/spectrum.02591-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/10/2023] [Indexed: 11/19/2023] Open
Abstract
IMPORTANCE We report the application of a colorimetric and fluorescent reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay to facilitate mass screening for sarbecoviruses in bats. The assay was evaluated using a total of 838 oral and alimentary samples from bats and demonstrated comparable sensitivity and specificity to quantitative reverse transcription PCR (qRT-PCR), with a simple setup. The addition of SYTO9, a fluorescent nucleic acid stain, also allows for quantitative analysis. The scalability and simplicity of the assay are believed to contribute to improving preparedness for detecting emerging coronaviruses by applying it to field studies and surveillance.
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Affiliation(s)
- Tony Tat-Yin Chan
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Franklin Wang-Ngai Chow
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Joshua Fung
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Flora Ka-Kei Cheng
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - George Chi-Shing Lo
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Chi-Ching Tsang
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- School of Medical and Health Sciences, Tung Wah College, Hong Kong, China
| | - Hayes Kam-Hei Luk
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Antonio Cheuk-Pui Wong
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Zirong He
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kam Leng Aw-Yong
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Xueyan Liu
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kwok-Yung Yuen
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Patrick Chiu-Yat Woo
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- Doctoral Program in Translational Medicine and Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
- The iEGG and Animal Biotechnology Research Center, National Chung Hsing University, Taichung, Taiwan
| | - Susanna Kar-Pui Lau
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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Lau SK, Wong AC, Luk HK, Li KS, Fung J, He Z, Cheng FK, Chan TT, Chu S, Aw-Yong KL, Lau TC, Fung KS, Woo PC. Differential Tropism of SARS-CoV and SARS-CoV-2 in Bat Cells. Emerg Infect Dis 2020; 26:2961-2965. [PMID: 32730733 PMCID: PMC7706959 DOI: 10.3201/eid2612.202308] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 did not replicate efficiently in 13 bat cell lines, whereas severe acute respiratory syndrome coronavirus replicated efficiently in kidney cells of its ancestral host, the Rhinolophus sinicus bat, suggesting different evolutionary origins. Structural modeling showed that RBD/RsACE2 binding may contribute to the differential cellular tropism.
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Aw-Yong KL, Sam IC, Koh MT, Chan YF. Causative agents of hand, foot and mouth disease in University Malaya Medical Centre, Kuala Lumpur, Malaysia in 2012-2013. Trop Biomed 2017; 34:240-248. [PMID: 33593003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Hand, foot and mouth disease (HFMD) is a childhood illness, commonly caused by enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16). In recent years, unusual HFMD outbreaks caused by coxsackievirus A6 (CV-A6) have been reported. From May 2012 to September 2013, enteroviruses were detected in 25 HFMD patients in University Malaya Medical Centre, Kuala Lumpur, Malaysia. The predominant serotypes were EV-A71 (48%) and CV-A6 (48%), followed by CV-A16 (4%). CV-A6 patients (mean age, 2.1) were significantly younger than EV-A71 patients (mean age, 3.3). There were no significant differences observed in clinical features between EV-A71 and CV-A6 patients. Since enteroviruses are difficult to differentiate clinically, the conserved 5' untranslated region (5' UTR) was used to identify enterovirus serotypes. Phylogenetic analysis of 5' UTR showed distinct clustering of viruses as EV-A71, CV-A16 and CV-A6. Further genotyping with capsid genes showed that all the EVA71 sequences belonged to subgenotype B5, while the CV-A16 sequence belonged to subgenotype B2b. CV-A6 sequences were clustered into genotypes D1 and D2, with recent isolates from Seri Kembangan, Malaysia and China. In summary, 59.5% of HFMD cases in our centre in 2012-2013 were caused by EV-A71, CV-A16 and the newly emerging CV-A6. This study also demonstrated that 5' UTR is suitable for preliminary identification of enteroviruses during HFMD outbreaks, but specific capsid genes such as VP1 and VP4/VP2 are required for further genotyping. Apart from measures to control the spread of the virus during an outbreak of HFMD, identification of EV-A71 as the etiological agent is important as EV-A71 is a major cause of severe neurological complications and potentially fatal.
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Affiliation(s)
- K L Aw-Yong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - I C Sam
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - M T Koh
- Department of Paediatrics, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Y F Chan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
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Aw-Yong KL, Sam IC, Koh MT, Chan YF. Immunodominant IgM and IgG Epitopes Recognized by Antibodies Induced in Enterovirus A71-Associated Hand, Foot and Mouth Disease Patients. PLoS One 2016; 11:e0165659. [PMID: 27806091 PMCID: PMC5091889 DOI: 10.1371/journal.pone.0165659] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/26/2016] [Indexed: 01/20/2023] Open
Abstract
Enterovirus A71 (EV-A71) is one of the main causative agents of hand, foot and mouth disease (HFMD). Unlike other enteroviruses that cause HFMD, EV-A71 is more frequently associated with severe neurological complications and fatality. To date, no effective licensed antivirals are available to combat EV-A71 infection. Little is known about the immunogenicity of viral non-structural proteins in humans. Previous studies have mainly focused on characterization of epitopes of EV-A71 structural proteins by using immunized animal antisera. In this study, we have characterized human antibody responses against the structural and non-structural proteins of EV-A71. Each viral protein was cloned and expressed in either bacterial or mammalian systems, and tested with antisera by western blot. Results revealed that all structural proteins (VP1-4), and non-structural proteins 2A, 3C and 3D were targets of EV-A71 IgM, whereas EV-A71 IgG recognized all the structural and non-structural proteins. Sixty three synthetic peptides predicted to be immunogenic in silico were synthesized and used for the characterization of EV-A71 linear B-cell epitopes. In total, we identified 22 IgM and four IgG dominant epitopes. Synthetic peptide PEP27, corresponding to residues 142-156 of VP1, was identified as the EV-A71 IgM-specific immunodominant epitope. PEP23, mapped to VP1 41-55, was recognized as the EV-A71 IgG cross-reactive immunodominant epitope. The structural protein VP1 is the major immunodominant site targeted by anti-EV-A71 IgM and IgG antibodies, but epitopes against non-structural proteins were also detected. These data provide new understanding of the immune response to EV-A71 infection, which benefits the development of diagnostic tools, potential therapeutics and subunit vaccine candidates.
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Affiliation(s)
- Kam Leng Aw-Yong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - I-Ching Sam
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Mia Tuang Koh
- Department of Paediatrics, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yoke Fun Chan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
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Aw-Yong KL, Tan CW, Koh MT, Sam IC, Chan YF. Diagnosis of human enterovirus A71 infection in Malaysia using a commercial IgM-capture enzyme-linked immunosorbent assay and an IgM-colloidal gold immunochromatographic assay. Trop Biomed 2016; 33:238-245. [PMID: 33579090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Hand, foot and mouth disease (HFMD) is a common childhood infection caused by many enteroviruses, including enterovirus A71 (EV-A71). As EV-A71 is associated with severe neurological disease, early diagnosis is critical for clinical and public health management. In developing countries such as Malaysia, laboratory capacity to carry out EV-A71 IgM detection is greater than that of the gold standard methods of virus culture or molecular detection. This study evaluated two diagnostic kits, EV-A71 IgM-capture enzyme-linked immunosorbent (ELISA) and EV-A71 IgM-colloidal gold immunochromatographic assay (GICA), which had previously only been assessed in China. The assays were tested with 89 serum samples from patients with suspected HFMD. The sensitivity, specificity, positive predictive value, and negative predictive value rates were 78.4%, 80.8%, 74.4%, and 84.0%, respectively, for the IgM-capture ELISA, and 75.7%, 76.9%, 70.0%, and 81.6% for the IgM GICA. These performance measures were similar between the two assays. Concordance between the two assays was 91.1%. The sensitivity rates were lower than those previously reported, likely because the multiple circulating EV-A71 genotypes in Malaysia differ from the C4 subgenotype found in China and used in the assays. Both assays had low false positive rates (12.5% and 16.7% for ELISA and GICA, respectively) when tested on sera from patients confirmed to have enteroviruses. Both diagnostic kits are suitable for early diagnosis of HFMD caused by EVA71 in Malaysia, but confirmation with culture or PCR is still important.
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Affiliation(s)
- K L Aw-Yong
- Department of Medical Microbiology, Faculty of Medicine, University Malaya, 50603 Kuala Lumpur, Malaysia
| | - C W Tan
- Department of Medical Microbiology, Faculty of Medicine, University Malaya, 50603 Kuala Lumpur, Malaysia
| | - M T Koh
- Department of Paediatrics, Faculty of Medicine, University Malaya, 50603 Kuala Lumpur, Malaysia
| | - I C Sam
- Department of Medical Microbiology, Faculty of Medicine, University Malaya, 50603 Kuala Lumpur, Malaysia
| | - Y F Chan
- Department of Medical Microbiology, Faculty of Medicine, University Malaya, 50603 Kuala Lumpur, Malaysia
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