Displaying publications 1 - 20 of 34 in total

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  1. Nipah virus outbreak in Malaysia
    Chua KB
    J Clin Virol, 2003 Apr;26(3):265-75.
    PMID: 12637075
    Nipah virus, a novel paramyxovirus, closely related to Hendra virus emerged in northern part of Peninsular Malaysia in 1998. The virus caused an outbreak of severe febrile encephalitis in humans with a high mortality rate, whereas, in pigs, encephalitis and respiratory diseases but with a relatively low mortality rate. The outbreak subsequently spread to various regions of the country and Singapore in the south due to the movement of infected pigs. Nipah virus caused systemic infections in humans, pigs and other mammals. Histopathological and radiological findings were characteristic of the disease. Fruitbats of Pteropid species were identified as the natural reservoir hosts. Evidence suggested that climatic and anthropogenic driven ecological changes coupled with the location of piggeries in orchard and the design of pigsties allowed the spill-over of this novel paramyxovirus from its reservoir host into the domestic pigs and ultimately to humans and other animals.
    Matched MeSH terms: Respiratory Tract Infections/virology
  2. Fulltext Nipah virus: a recently emergent deadly paramyxovirus
    Chua KB, Bellini WJ, Rota PA, Harcourt BH, Tamin A, Lam SK, et al.
    Science, 2000 May 26;288(5470):1432-5.
    PMID: 10827955
    A paramyxovirus virus termed Nipah virus has been identified as the etiologic agent of an outbreak of severe encephalitis in people with close contact exposure to pigs in Malaysia and Singapore. The outbreak was first noted in late September 1998 and by mid-June 1999, more than 265 encephalitis cases, including 105 deaths, had been reported in Malaysia, and 11 cases of encephalitis or respiratory illness with one death had been reported in Singapore. Electron microscopic, serologic, and genetic studies indicate that this virus belongs to the family Paramyxoviridae and is most closely related to the recently discovered Hendra virus. We suggest that these two viruses are representative of a new genus within the family Paramyxoviridae. Like Hendra virus, Nipah virus is unusual among the paramyxoviruses in its ability to infect and cause potentially fatal disease in a number of host species, including humans.
    Matched MeSH terms: Respiratory Tract Infections/virology
  3. Experimental Nipah virus infection in pigs and cats
    Middleton DJ, Westbury HA, Morrissy CJ, van der Heide BM, Russell GM, Braun MA, et al.
    J Comp Pathol, 2002 Feb-Apr;126(2-3):124-36.
    PMID: 11945001 DOI: 10.1053/jcpa.2001.0532
    A human isolate of Nipah virus from an outbreak of febrile encephalitis in Malaysia that coincided with a field outbreak of disease in pigs was used to infect eight 6-week-old pigs orally or subcutaneously and two cats oronasally. In pigs, the virus induced a respiratory and neurological syndrome consistent with that observed in the Malaysian pigs. Not all the pigs showed clinical signs, but Nipah virus was recovered from the nose and oropharynx of both clinically and sub-clinically infected animals. Natural infection of in-contact pigs, which was readily demonstrated, appeared to be acute and self-limiting. Subclinical infections occurred in both inoculated and in-contact pigs. Respiratory and neurological disease was also produced in the cats, with recovery of virus from urine as well as from the oropharynx. The clinical and pathological syndrome induced by Nipah virus in cats was comparable with that associated with Hendra virus infection in this species, except that in fatal infection with Nipah virus there was extensive inflammation of the respiratory epithelium, associated with the presence of viral antigen. Viral shedding via the nasopharynx, as observed in pigs and cats in the present study, was not a regular feature of earlier reports of experimental Hendra virus infection in cats and horses. The findings indicate the possibility of field transmission of Nipah virus between pigs via respiratory and oropharyngeal secretions.
    Matched MeSH terms: Respiratory Tract Infections/virology
  4. Fulltext Bioinformatics analysis reveals four major hexon variants of human adenovirus type-3 (HAdV-3) as the potential strains for development of vaccine and siRNA-based therapeutics against HAdV-3 respiratory infections
    Panda S, Banik U, Adhikary AK
    Infect Genet Evol, 2020 11;85:104439.
    PMID: 32585339 DOI: 10.1016/j.meegid.2020.104439
    Human adenovirus type 3 (HAdV-3) encompasses 15-87% of all adenoviral respiratory infections. The significant morbidity and mortality, especially among the neonates and immunosuppressed patients, demand the need for a vaccine or a targeted antiviral against this type. However, due to the existence of multiple hexon variants (3Hv-1 to 3Hv-25), the selection of vaccine strains of HAdV-3 is challenging. This study was designed to evaluate HAdV-3 hexon variants for the selection of potential vaccine candidates and the use of hexon gene as a target for designing siRNA that can be used as a therapy. Based on the data of worldwide distribution, duration of circulation, co-circulation and their percentage among all the variants, 3Hv-1 to 3Hv-4 were categorized as the major hexon variants. Phylogenetic analysis and the percentage of homology in the hypervariable regions followed by multi-sequence alignment, zPicture analysis and restriction enzyme analysis were carried out. In the phylogram, the variants were arranged in different clusters. The HVR encoding regions of hexon of 3Hv-1 to 3Hv-4 showed 16 point mutations resulting in 12 amino acids substitutions. The homology in HVRs was 81.81-100%. Therefore, the major hexon variants are substantially different from each other which justifies their inclusion as the potential vaccine candidates. Interestingly, despite the significant differences in the DNA sequence, there were many conserved areas in the HVRs, and we have designed functional siRNAs form those locations. We have also designed immunogenic vaccine peptide epitopes from the hexon protein using bioinformatics prediction tool. We hope that our developed siRNAs and immunogenic vaccine peptide epitopes could be used in the future development of siRNA-based therapy and designing a vaccine against HAdV-3.
    Matched MeSH terms: Respiratory Tract Infections/virology
  5. Identification and evolutionary dynamics of two novel human coronavirus OC43 genotypes associated with acute respiratory infections: phylogenetic, spatiotemporal and transmission network analyses
    Oong XY, Ng KT, Takebe Y, Ng LJ, Chan KG, Chook JB, et al.
    Emerg Microbes Infect, 2017 Jan 04;6(1):e3.
    PMID: 28050020 DOI: 10.1038/emi.2016.132
    Human coronavirus OC43 (HCoV-OC43) is commonly associated with respiratory tract infections in humans, with five genetically distinct genotypes (A to E) described so far. In this study, we obtained the full-length genomes of HCoV-OC43 strains from two previously unrecognized lineages identified among patients presenting with severe upper respiratory tract symptoms in a cross-sectional molecular surveillance study in Kuala Lumpur, Malaysia, between 2012 and 2013. Phylogenetic, recombination and comparative genomic analyses revealed two distinct clusters diverging from a genotype D-like common ancestor through recombination with a putative genotype A-like lineage in the non-structural protein (nsp) 10 gene. Signature amino acid substitutions and a glycine residue insertion at the N-terminal domain of the S1 subunit of the spike gene, among others, exhibited further distinction in a recombination pattern, to which these clusters were classified as genotypes F and G. The phylogeographic mapping of the global spike gene indicated that the genetically similar HCoV-OC43 genotypes F and G strains were potentially circulating in China, Japan, Thailand and Europe as early as the late 2000s. The transmission network construction based on the TN93 pairwise genetic distance revealed the emergence and persistence of multiple sub-epidemic clusters of the highly prevalent genotype D and its descendant genotypes F and G, which contributed to the spread of HCoV-OC43 in the region. Finally, a more consistent nomenclature system for non-recombinant and recombinant HCoV-OC43 lineages is proposed, taking into account genetic recombination as an important feature in HCoV evolution and classification.
    Matched MeSH terms: Respiratory Tract Infections/virology*
  6. Fulltext The role of human Metapneumovirus genetic diversity and nasopharyngeal viral load on symptom severity in adults
    Oong XY, Chook JB, Ng KT, Chow WZ, Chan KG, Hanafi NS, et al.
    Virol J, 2018 05 23;15(1):91.
    PMID: 29792212 DOI: 10.1186/s12985-018-1005-8
    BACKGROUND: Human metapneumovirus (HMPV) is established as one of the causative agents of respiratory tract infections. To date, there are limited reports that describe the effect of HMPV genotypes and/or viral load on disease pathogenesis in adults. This study aims to determine the role of HMPV genetic diversity and nasopharyngeal viral load on symptom severity in outpatient adults with acute respiratory tract infections.
    METHODS: Severity of common cold symptoms of patients from a teaching hospital was assessed by a four-category scale and summed to obtain the total symptom severity score (TSSS). Association between the fusion and glycoprotein genes diversity, viral load (quantified using an improved RT-qPCR assay), and symptom severity were analyzed using bivariate and linear regression analyses.
    RESULTS: Among 81/3706 HMPV-positive patients, there were no significant differences in terms of demographics, number of days elapsed between symptom onset and clinic visit, respiratory symptoms manifestation and severity between different HMPV genotypes/sub-lineages. Surprisingly, elderly patients (≥65 years old) had lower severity of symptoms (indicated by TSSS) than young and middle age adults (p = 0.008). Nasopharyngeal viral load did not correlate with nor predict symptom severity of HMPV infection. Interestingly, at 3-5 days after symptom onset, genotype A-infected patients had higher viral load compared to genotype B (4.4 vs. 3.3 log10 RNA copies/μl) (p = 0.003).
    CONCLUSIONS: Overall, HMPV genetic diversity and viral load did not impact symptom severity in adults with acute respiratory tract infections. Differences in viral load dynamics over time between genotypes may have important implications on viral transmission.
    Study site: Primary Care Clinic, University of Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
    Matched MeSH terms: Respiratory Tract Infections/virology
  7. Fulltext The Nature of Exposure Drives Transmission of Nipah Viruses from Malaysia and Bangladesh in Ferrets
    Clayton BA, Middleton D, Arkinstall R, Frazer L, Wang LF, Marsh GA
    PLoS Negl Trop Dis, 2016 06;10(6):e0004775.
    PMID: 27341030 DOI: 10.1371/journal.pntd.0004775
    Person-to-person transmission is a key feature of human Nipah virus outbreaks in Bangladesh. In contrast, in an outbreak of Nipah virus in Malaysia, people acquired infections from pigs. It is not known whether this important epidemiological difference is driven primarily by differences between NiV Bangladesh (NiV-BD) and Malaysia (NiV-MY) at a virus level, or by environmental or host factors. In a time course study, ferrets were oronasally exposed to equivalent doses of NiV-BD or NiV-MY. More rapid onset of productive infection and higher levels of virus replication in respiratory tract tissues were seen for NiV-BD compared to NiV-MY, corroborating our previous report of increased oral shedding of NiV-BD in ferrets and suggesting a contributory mechanism for increased NiV-BD transmission between people compared to NiV-MY. However, we recognize that transmission occurs within a social and environmental framework that may have an important and differentiating role in NiV transmission rates. With this in mind, ferret-to-ferret transmission of NiV-BD and NiV-MY was assessed under differing viral exposure conditions. Transmission was not identified for either virus when naïve ferrets were cohoused with experimentally-infected animals. In contrast, all naïve ferrets developed acute infection following assisted and direct exposure to oronasal fluid from animals that were shedding either NiV-BD or NiV-MY. Our findings for ferrets indicate that, although NiV-BD may be shed at higher levels than NiV-MY, transmission risk may be equivalently low under exposure conditions provided by cohabitation alone. In contrast, active transfer of infected bodily fluids consistently results in transmission, regardless of the virus strain. These observations suggest that the risk of NiV transmission is underpinned by social and environmental factors, and will have practical implications for managing transmission risk during outbreaks of human disease.
    Matched MeSH terms: Respiratory Tract Infections/virology
  8. Epidemiology of adenovirus respiratory infections among hospitalized children in Seremban, Malaysia
    Foong Ng K, Kee Tan K, Hong Ng B, Nair P, Ying Gan W
    Trans R Soc Trop Med Hyg, 2015 Jul;109(7):433-9.
    PMID: 26038572 DOI: 10.1093/trstmh/trv042
    There is scarcity of data regarding epidemiology and clinical aspects of human adenovirus acute respiratory infection (ARI) among children in developing countries.
    Matched MeSH terms: Respiratory Tract Infections/virology*
  9. Fulltext Evaluation of WHO monoclonal antibody kit for diagnosis of acute respiratory viral infections
    Khairullah NS, Lam SK
    Southeast Asian J. Trop. Med. Public Health, 1995 Jun;26(2):263-7.
    PMID: 8629057
    In 1990 and 1991, six laboratories located in the WHO Western Pacific Region (WPR) and South East Asian Region (SEAR) were selected, based on their experience in the immunofluorescence antibody technique (IFAT), to participate in the evaluation of a WHO monoclonal antibody (Mab) kit to detect respiratory syncytial (RS) virus, influenza A virus, influenza B virus, parainfluenza virus and adenovirus. Despite differences in the initial standardization procedures, the WHO monoclonal antibodies were found to be of high quality, sensitivity and specificity when tested on clinical specimens. The constant supply of affordable high quality reagents from WHO would enable their use in clinical virological laboratories in the developing countries as well as promote the utilization of IFAT as an adjunct to cell culture isolation in the diagnosis of acute respiratory viral infections.
    Matched MeSH terms: Respiratory Tract Infections/virology
  10. Fulltext Genetic diversity of Coxsackievirus A21 associated with sporadic cases of acute respiratory infections in Malaysia
    Supian NI, Ng KT, Chook JB, Takebe Y, Chan KG, Tee KK
    BMC Infect Dis, 2021 May 17;21(1):446.
    PMID: 34001016 DOI: 10.1186/s12879-021-06148-x
    BACKGROUND: Coxsackievirus A21 (CVA21), a member of Enterovirus C from the Picornaviridae family, has been associated with respiratory illnesses in humans.

    METHODS: A molecular epidemiological investigation of CVA21 was conducted among patients presenting with acute upper respiratory illnesses in the ambulatory settings between 2012 and 2014 in Kuala Lumpur, Malaysia.

    RESULTS: Epidemiological surveillance of acute respiratory infections (n = 3935) showed low-level detection of CVA21 (0.08%, 1.4 cases/year) in Kuala Lumpur, with no clear seasonal distribution. Phylogenetic analysis of the new complete genomes showed close relationship with CVA21 strains from China and the United States. Spatio-temporal mapping of the VP1 gene determined 2 major clusters circulating worldwide, with inter-country lineage migration and strain replacement occurring over time.

    CONCLUSIONS: The study highlights the emerging role of CVA21 in causing sporadic acute respiratory outbreaks.

    Matched MeSH terms: Respiratory Tract Infections/virology
  11. Fulltext Pteropine orthoreovirus infection among out-patients with acute upper respiratory tract infection in Malaysia
    Voon K, Tan YF, Leong PP, Teng CL, Gunnasekaran R, Ujang K, et al.
    J Med Virol, 2015 Dec;87(12):2149-53.
    PMID: 26106066 DOI: 10.1002/jmv.24304
    This study aims to assess the incidence rate of Pteropine orthreovirus (PRV) infection in patients with acute upper respiratory tract infection (URTI) in a suburban setting in Malaysia, where bats are known to be present in the neighborhood. Using molecular detection of PRVs directly from oropharyngeal swabs, our study demonstrates that PRV is among one of the common causative agents of acute URTI with cough and sore throat as the commonest presenting clinical features. Phylogenetic analysis on partial major outer and inner capsid proteins shows that these PRV strains are closely related to Melaka and Kampar viruses previously isolated in Malaysia. Further study is required to determine the public health significance of PRV infection in Southeast Asia, especially in cases where co-infection with other pathogens may potentially lead to different clinical outcomes.
    Matched MeSH terms: Respiratory Tract Infections/virology*
  12. Fulltext Phylogenetic analysis of human metapneumovirus among children with acute respiratory infections in Kuala Lumpur, Malaysia
    Nor'e SS, Sam IC, Mohamad Fakri EF, Hooi PS, Nathan AM, de Bruyne JA, et al.
    Trop Biomed, 2014 Sep;31(3):562-6.
    PMID: 25382484 MyJurnal
    Human metapneumovirus (HMPV) is a recently discovered cause of viral respiratory infections. We describe clinical and molecular epidemiology of HMPV cases diagnosed in children with respiratory infection at University of Malaya Medical Centre, Kuala Lumpur, Malaysia. The prevalence rate of HMPV between 2010 and 2012 was 1.1%, and HMPV contributed 6.5% of confirmed viral respiratory infections. The HMPV patients had a median age of 1.6 years, and a median hospital admission of 4 days. The most common clinical presentations were fever, rhinitis, pneumonia, vomiting/diarrhoea, and bronchiolitis. Based on the partial sequences of F fusion gene from 26 HMPV strains, 14 (54%) were subgenotype A2b, which was predominant in 2010; 11 (42%) were subgenotype B1, which was predominant in 2012; and 1 (4%) was subgenotype A2a. Knowledge of the circulating subgenotypes in Malaysia, and the displacement of predominant subgenotypes within 3 years, is useful data for future vaccine planning.
    Matched MeSH terms: Respiratory Tract Infections/virology*
  13. Fulltext Worldwide increased prevalence of human adenovirus type 3 (HAdV-3) respiratory infections is well correlated with heterogeneous hypervariable regions (HVRs) of hexon
    Haque E, Banik U, Monwar T, Anthony L, Adhikary AK
    PLoS One, 2018;13(3):e0194516.
    PMID: 29590206 DOI: 10.1371/journal.pone.0194516
    Human adenovirus type 3 (HAdV-3) respiratory infections occurs worldwide in both children and adults, leading to severe morbidity and mortality, particularly in the paediatric age group and especially in neonates. During HAdV infection, neutralizing antibodies are formed against the epitopes located in the hyper variable regions (HVRs) of the hexon protein. These neutralizing antibodies provide protection against reinfection by viruses of the same type. Therefore it is reasonable to speculate that variations of HAdV-3 in the HVRs could impair the immunity acquired by previous infection with a different strain with variation in its HVRs. HAdV-3 has recently become the major agent of acute respiratory infection worldwide, being responsible for 15% to 87% of all adenoviral respiratory infections. However, despite the increased prevalence of HAdV-3 as respiratory pathogen, the diversity of hexon proteins in circulating strains remains unexplored. This study was designed to explore the variation in HVRs of hexon among globally distributed strains of HAdV-3 as well as to discover possible relationship among them, thus possibly shedding light on the cause for the increased prevalence of HAdV-3. In this study, for the first time we analysed the hexon proteins of all 248 available strains of HAdV-3 from the NCBI database and compared them with those of the HAdV-3 prototype (GB stain). We found that the HVRs of HAdV-3 strains circulating worldwide were highly heterogeneous and have been mutating continuously since -their original isolation. Based on their immense heterogeneity, the strains can be categorized into 25 hexon variants (3Hv-1 to 3Hv-25), 4 of which (3Hv-1 to 3Hv-4) comprises 80% of the strains. This heterogeneity may explain why HAdV-3 has become the most prevalent HAdVs type worldwide. The heterogeneity of hexon proteins also shows that the development of a vaccine against HAdV-3 might be challenging. The data on hexon variants provided here may be useful for the future epidemiological study of HAdV-3 infection.
    Matched MeSH terms: Respiratory Tract Infections/virology
  14. Fulltext Detection of novel respiratory viruses from influenza-like illness in the Philippines
    Furuse Y, Suzuki A, Kishi M, Galang HO, Lupisan SP, Olveda RM, et al.
    J Med Virol, 2010 May;82(6):1071-4.
    PMID: 20419824 DOI: 10.1002/jmv.21763
    Several novel viruses have been recently identified in respiratory samples. However, the epidemiology of these viruses in tropical countries remains unclear. The aim of the present study was to provide an overview of the epidemiology of novel respiratory viruses, including human metapneumovirus, human bocavirus, new subtypes of human coronavirus (NL63 and HKU1), KI virus, WU virus, and Melaka virus in the Philippines, a tropical country. Nasopharyngeal aspirates from 465 patients with influenza-like illness were collected in 2006 and 2007. Reverse transcription polymerase chain reaction (RT-PCR) and PCR were performed to detect viruses from culture-negative specimens. Human metapneumovirus, human bocavirus, human coronavirus HKU1, KI virus, and WU virus were detected for the first time in the Philippines; Melaka virus was not found.
    Matched MeSH terms: Respiratory Tract Infections/virology*
  15. Fulltext Laboratory-confirmed case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in Malaysia: preparedness and response, April 2014
    Premila Devi J, Noraini W, Norhayati R, Chee Kheong C, Badrul AS, Zainah S, et al.
    Euro Surveill, 2014 May 08;19(18).
    PMID: 24832116
    On 14 April 2014, the first laboratory-confirmed case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection was reported in Malaysia in a man in his mid-fifties, who developed pneumonia with respiratory distress, after returning from a pilgrimage to Saudi Arabia. The case succumbed to his illness three days after admission at a local hospital. The follow-up of 199 close contacts identified through contact tracing and vigilant surveillance did not result in detecting any other confirmed cases of MERS-CoV infection.
    Matched MeSH terms: Respiratory Tract Infections/virology
  16. Fulltext Knowledge, attitudes and practices towards antibiotic use in upper respiratory tract infections among patients seeking primary health care in Singapore
    Pan DS, Huang JH, Lee MH, Yu Y, Chen MI, Goh EH, et al.
    BMC Fam Pract, 2016 11 03;17(1):148.
    PMID: 27809770 DOI: 10.1186/s12875-016-0547-3
    BACKGROUND: Patients' expectations can influence antibiotic prescription by primary healthcare physicians. We assessed knowledge, attitude and practices towards antibiotic use for upper respiratory tract infections (URTIs), and whether knowledge is associated with increased expectations for antibiotics among patients visiting primary healthcare services in Singapore.

    METHODS: Data was collected through a cross-sectional interviewer-assisted survey of patients aged ≥21 years waiting to see primary healthcare practitioners for one or more symptoms suggestive of URTI (cough, sore throat, runny nose or blocked nose) for 7 days or less, covering the demographics, presenting symptoms, knowledge, attitudes, beliefs and practices of URTI and associated antibiotic use. Univariate and multivariate logistic regression was used to assess independent factors associated with patients' expectations for antibiotics.

    RESULTS: Nine hundred fourteen out of 987 eligible patients consulting 35 doctors were recruited from 24 private sector primary care clinics in Singapore. A third (307/907) expected antibiotics, of which a substantial proportion would ask the doctor for antibiotics (121/304, 40 %) and/or see another doctor (31/304, 10 %) if antibiotics were not prescribed. The majority agreed "antibiotics are effective against viruses" (715/914, 78 %) and that "antibiotics cure URTI faster" (594/912, 65 %). Inappropriate antibiotic practices include "keeping antibiotics stock at home" (125/913, 12 %), "taking leftover antibiotics" (114/913, 14 %) and giving antibiotics to family members (62/913, 7 %). On multivariate regression, the following factors were independently associated with wanting antibiotics (odds ratio; 95 % confidence interval): Malay ethnicity (1.67; 1.00-2.79), living in private housing (1.69; 1.13-2.51), presence of sore throat (1.50; 1.07-2.10) or fever (1.46; 1.01-2.12), perception that illness is serious (1.70; 1.27-2.27), belief that antibiotics cure URTI faster (5.35; 3.76-7.62) and not knowing URTI resolves on its own (2.18; 1.08-2.06), while post-secondary education (0.67; 0.48-0.94) was inversely associated. Those with lower educational levels were significantly more likely to have multiple misconceptions about antibiotics.

    CONCLUSION: Majority of patients seeking primary health care in Singapore are misinformed about the role of antibiotics in URTI. Agreeing with the statement that antibiotics cure URTI faster was most strongly associated with wanting antibiotics. Those with higher educational levels were less likely to want antibiotics, while those with lower educational levels more likely to have incorrect knowledge.
    Matched MeSH terms: Respiratory Tract Infections/virology
  17. Viral Load and Sequence Analysis Reveal the Symptom Severity, Diversity, and Transmission Clusters of Rhinovirus Infections
    Ng KT, Oong XY, Lim SH, Chook JB, Takebe Y, Chan YF, et al.
    Clin Infect Dis, 2018 07 02;67(2):261-268.
    PMID: 29385423 DOI: 10.1093/cid/ciy063
    Background: Rhinovirus (RV) is one of the main viral etiologic agents of acute respiratory illnesses. Despite the heightened disease burden caused by RV, the viral factors that increase the severity of RV infection, the transmission pattern, and seasonality of RV infections remain unclear.

    Methods: An observational study was conducted among 3935 patients presenting with acute upper respiratory illnesses in the ambulatory settings between 2012 and 2014.

    Results: The VP4/VP2 gene was genotyped from all 976 RV-positive specimens, where the predominance of RV-A (49%) was observed, followed by RV-C (38%) and RV-B (13%). A significant regression in median nasopharyngeal viral load (VL) (P < .001) was observed, from 883 viral copies/µL at 1-2 days after symptom onset to 312 viral copies/µL at 3-4 days and 158 viral copies/µL at 5-7 days, before declining to 35 viral copies/µL at ≥8 days. In comparison with RV-A (median VL, 217 copies/µL) and RV-B (median VL, 275 copies/µL), RV-C-infected subjects produced higher VL (505 copies/µL; P < .001). Importantly, higher RV VL (median, 348 copies/µL) was associated with more severe respiratory symptoms (Total Symptom Severity Score ≥17, P = .017). A total of 83 phylogenetic-based transmission clusters were identified in the population. It was observed that the relative humidity was the strongest environmental predictor of RV seasonality in the tropical climate.

    Conclusions: Our findings underline the role of VL in increasing disease severity attributed to RV-C infection, and unravel the factors that fuel the population transmission dynamics of RV.

    Matched MeSH terms: Respiratory Tract Infections/virology*
  18. Fulltext Revolutionizing polymer-based nanoparticle-linked vaccines for targeting respiratory viruses: A perspective
    Chan Y, Ng SW, Singh SK, Gulati M, Gupta G, Chaudhary SK, et al.
    Life Sci, 2021 Sep 01;280:119744.
    PMID: 34174324 DOI: 10.1016/j.lfs.2021.119744
    Viral respiratory tract infections have significantly impacted global health as well as socio-economic growth. Respiratory viruses such as the influenza virus, respiratory syncytial virus (RSV), and the recent SARS-CoV-2 infection (COVID-19) typically infect the upper respiratory tract by entry through the respiratory mucosa before reaching the lower respiratory tract, resulting in respiratory disease. Generally, vaccination is the primary method in preventing virus pathogenicity and it has been shown to remarkably reduce the burden of various infectious diseases. Nevertheless, the efficacy of conventional vaccines may be hindered by certain limitations, prompting the need to develop novel vaccine delivery vehicles to immunize against various strains of respiratory viruses and to mitigate the risk of a pandemic. In this review, we provide an insight into how polymer-based nanoparticles can be integrated with the development of vaccines to effectively enhance immune responses for combating viral respiratory tract infections.
    Matched MeSH terms: Respiratory Tract Infections/virology*
  19. Fulltext Diversity of respiratory viruses detected among hospitalized children with acute lower respiratory tract infections at Hospital Serdang, Malaysia
    Etemadi MR, Jalilian FA, Othman N, Lye MS, Ansari S, Yubbu P, et al.
    J Virol Methods, 2019 07;269:1-6.
    PMID: 30910688 DOI: 10.1016/j.jviromet.2019.03.013
    BACKGROUND: The role of respiratory viruses as the major cause of acute lower respiratory tract infections (ALRTIs) in children is becoming increasingly evident due to the use of sensitive molecular detection methods. The aim of this study was to use conventional and molecular detection methods to assess the epidemiology of respiratory viral infections in children less than five years of age that were hospitalized with ALRTIs.

    METHODS: The cross-sectional study was designed to investigate the occurrence of respiratory viruses including respiratory syncytisl virus (RSV), human metapneumovirus (HMPV), influenza virus A and B (IFV-A and B), parainfluenzavirus 1, 2, 3 and 4 (PIV 1, 2, 3 and 4), human rhinoviruses (HRV), human enterovirus (HEV), human coronaviruses (HCoV) 229E and OC43, human bocavirus (HBoV) and human adenovirus (HAdV) in hospitalized children with ALRTIs, at Hospital Serdang, Malaysia, from June 16 to December 21, 2009. The study was also designed in part to assess the performance of the conventional methods against molecular methods.

    RESULTS: Viral pathogens were detected in 158 (95.8%) of the patients. Single virus infections were detected in 114 (67.9%) patients; 46 (27.9%) were co-infected with different viruses including double-virus infections in 37 (22.4%) and triple-virus infections in 9 (5.5%) cases. Approximately 70% of samples were found to be positive using conventional methods compared with 96% using molecular methods. A wide range of respiratory viruses were detected in the study. There was a high prevalence of RSV (50.3%) infections, particularly group B viruses. Other etiological agents including HAdV, HMPV, IFV-A, PIV 1-3, HBoV, HCoV-OC43 and HEV were detected in 14.5, 9.6, 9.1, 4.8, 3.6, 2.4 and 1.8 percent of the samples, respectively.

    CONCLUSION: Our results demonstrated the increased sensitivity of molecular detection methods compared with conventional methods for the diagnosis of ARTIs in hospitalized children. This is the first report of HMPV infections in Malaysia.

    Matched MeSH terms: Respiratory Tract Infections/virology*
  20. Fulltext Molecular epidemiology and evolutionary histories of human coronavirus OC43 and HKU1 among patients with upper respiratory tract infections in Kuala Lumpur, Malaysia
    Al-Khannaq MN, Ng KT, Oong XY, Pang YK, Takebe Y, Chook JB, et al.
    Virol J, 2016 Feb 25;13:33.
    PMID: 26916286 DOI: 10.1186/s12985-016-0488-4
    BACKGROUND: Despite the worldwide circulation of human coronavirus OC43 (HCoV-OC43) and HKU1 (HCoV-HKU1), data on their molecular epidemiology and evolutionary dynamics in the tropical Southeast Asia region is lacking.
    METHODS: The study aimed to investigate the genetic diversity, temporal distribution, population history and clinical symptoms of betacoronavirus infections in Kuala Lumpur, Malaysia between 2012 and 2013. A total of 2,060 adults presented with acute respiratory symptoms were screened for the presence of betacoronaviruses using multiplex PCR. The spike glycoprotein, nucleocapsid and 1a genes were sequenced for phylogenetic reconstruction and Bayesian coalescent inference.
    RESULTS: A total of 48/2060 (2.4 %) specimens were tested positive for HCoV-OC43 (1.3 %) and HCoV-HKU1 (1.1 %). Both HCoV-OC43 and HCoV-HKU1 were co-circulating throughout the year, with the lowest detection rates reported in the October-January period. Phylogenetic analysis of the spike gene showed that the majority of HCoV-OC43 isolates were grouped into two previously undefined genotypes, provisionally assigned as novel lineage 1 and novel lineage 2. Sign of natural recombination was observed in these potentially novel lineages. Location mapping showed that the novel lineage 1 is currently circulating in Malaysia, Thailand, Japan and China, while novel lineage 2 can be found in Malaysia and China. Molecular dating showed the origin of HCoV-OC43 around late 1950s, before it diverged into genotypes A (1960s), B (1990s), and other genotypes (2000s). Phylogenetic analysis revealed that 27.3 % of the HCoV-HKU1 strains belong to genotype A while 72.7 % belongs to genotype B. The tree root of HCoV-HKU1 was similar to that of HCoV-OC43, with the tMRCA of genotypes A and B estimated around the 1990s and 2000s, respectively. Correlation of HCoV-OC43 and HCoV-HKU1 with the severity of respiratory symptoms was not observed.
    CONCLUSIONS: The present study reported the molecular complexity and evolutionary dynamics of human betacoronaviruses among adults with acute respiratory symptoms in a tropical country. Two novel HCoV-OC43 genetic lineages were identified, warranting further investigation on their genotypic and phenotypic characteristics.
    Study site: Primary Care Clinic, University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
    Matched MeSH terms: Respiratory Tract Infections/virology*
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