Displaying publications 1 - 20 of 41 in total

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  1. Fulltext Spatio-temporal analysis on enterovirus cases through integrated surveillance in Taiwan
    Chan TC, Hwang JS, Chen RH, King CC, Chiang PH
    BMC Public Health, 2014 Jan 08;14:11.
    PMID: 24400725 DOI: 10.1186/1471-2458-14-11
    BACKGROUND: Severe epidemics of enterovirus have occurred frequently in Malaysia, Singapore, Taiwan, Cambodia, and China, involving cases of pulmonary edema, hemorrhage and encephalitis, and an effective vaccine has not been available. The specific aim of this study was to understand the epidemiological characteristics of mild and severe enterovirus cases through integrated surveillance data.

    METHODS: All enterovirus cases in Taiwan over almost ten years from three main databases, including national notifiable diseases surveillance, sentinel physician surveillance and laboratory surveillance programs from July 1, 1999 to December 31, 2008 were analyzed. The Pearson's correlation coefficient was applied for measuring the consistency of the trends in the cases between different surveillance systems. Cross correlation analysis in a time series model was applied for examining the capability to predict severe enterovirus infections. Poisson temporal, spatial and space-time scan statistics were used for identifying the most likely clusters of severe enterovirus outbreaks. The directional distribution method with two standard deviations of ellipse was applied to measure the size and the movement of the epidemic.

    RESULTS: The secular trend showed that the number of severe EV cases peaked in 2008, and the number of mild EV cases was significantly correlated with that of severe ones occurring in the same week [r = 0.553, p 

    Matched MeSH terms: Enterovirus Infections/virology
  2. Phylogenetic designation of enterovirus 71 genotypes and subgenotypes using complete genome sequences
    Chan YF, Sam IC, AbuBakar S
    Infect Genet Evol, 2010 Apr;10(3):404-12.
    PMID: 19465162 DOI: 10.1016/j.meegid.2009.05.010
    Human enterovirus 71 (EV-71) is genotyped for molecular epidemiological investigation mainly using the two structural genes, VP1 and VP4. Based on these, EV-71 is divided into three genotypes, A, B and C, and within the genotypes B and C, there are further subgenotypes, B1-B5 and C1-C5. Classification using these genes is useful but gives incomplete phylogenetic information. In the present study, the phylogenetic relationships amongst all the known EV-71 and human enterovirus A (HEV-A) isolates with complete genome sequences were examined. A different tree topology involving EV-71 isolates of subgenotypes, C4 and B5 was obtained in comparison to that drawn using VP1. The nucleotide sequence divergence of the C4 isolates was 18.11% (17-20%) when compared to other isolates of subgenotype C. However, this positions the C4 isolates within the cut-off divergence value of 17-22% used to designate the virus genotypes. Hence, it is proposed here that C4 should be designated as a new genotype D. In addition, the subgenotype B5 isolates had an average nucleotide divergence of only 6.14% (4-8%) when compared to other subgenotype B4 isolates. This places the B5 isolates within the subgenotype B4. It is proposed here that the B5 isolates to be redesignated as B4. With the newly proposed genotype D and inclusion of subgenotype B5 within B4, the average nucleotide divergence between genotypes was 18.99% (17-22%). Inter- and intra-subgenotype average divergences were 12.02% (10-14%) and 3.92% (1-10%), respectively. A phylogenetic tree built using the full genome sequences is robust as it takes into consideration changes in the sequences of both the structural and non-structural genes. Similar nucleotide similarities, however, were obtained if only VP1 and 3D RNA polymerase genes were used. Furthermore, addition of 3D RNA polymerase sequences will also show recombination events. Hence, in the absence of full genome sequences, it is proposed here that a combination of VP1 and 3D RNA polymerase gene sequences be used for initial genotyping of EV-71 isolates.
    Matched MeSH terms: Enterovirus Infections/virology
  3. Fulltext An outbreak of echovirus 11 amongst neonates in a confinement home in Penang, Malaysia
    Bina Rai S, Wan Mansor H, Vasantha T, Norizah I, Chua KB
    Med J Malaysia, 2007 Aug;62(3):223-6.
    PMID: 18246912 MyJurnal
    Confinement homes are private institutions that provide full-time care for newborn babies and their respective postpartum mothers up to one month after delivery. An outbreak of fever and diarrhoea amongst newborns occurred in one such confinement home in Penang between the months of September to October 2004. An outbreak investigation was carried out including all babies, their respective mothers and workers in the home to determine the source of the outbreak and to institute control measures. Based on a working case definition of febrile illness with or without diarrhoea, 11 out of the 13 babies in the confinement home met the case definition. One hundred percent had symptoms of fever. 36.4% had symptoms of diarrhea and other respiratory conditions respectively. The attack rate of among babies in the confinement home was 90%. Echovirus 11 was isolated from 3 out of the 11 febrile cases. Echovirus 11 was isolated from the cerebrospinal fluid and stool of another baby at a private hospital that was epidemiologically linked to the first case. In conclusion, the outbreak of febrile illness amongst newborn babies in the affected confinement home was due to echovirus 11. The source was probably health-care associated with efficient transmission within the confinement home. The faecal-oral route was the most likely mode of transmission.
    Matched MeSH terms: Enterovirus Infections/virology
  4. Characterization of species B adenoviruses isolated from fecal specimens taken from poliomyelitis-suspected cases
    de Azevedo JP, Nascimento LR, Cortinovis MC, Oliveira SS, da Costa EV, da Silva EE
    J Clin Virol, 2004 Dec;31(4):248-52.
    PMID: 15494264 DOI: 10.1016/j.jcv.2004.04.007
    BACKGROUND: Human adenoviruses are classified into six species, A-F, and 51 serotypes are recognized. Adenoviruses can cause a broad range of diseases. Serotypes 3, 7 and 21 are most commonly associated with CNS disease. Serotype 21 (specie B) was isolated from brain tissue and CSF of patients with acute flaccid paralysis (AFP) in Malaysia.
    OBJECTIVES: Characterize, by molecular methods, species B adenoviruses isolated from poliomyelitis-suspected cases and investigate the possible etiological role of adenoviruses in acute flaccid paralysis (AFP).
    STUDY DESIGN: 622 virus isolates, including Sabin-related polioviruses, non-polio enteroviruses (NPEV) and adenoviruses, were recovered from fecal specimens in our laboratory during the period of 1997-2002 from AFP cases occurring in Brazil, Peru and Bolivia. Negative controls consisted of 528 fecal specimens collected from healthy children <==5 of age. Of these, 478 were contacts of AFP negative cases and 50 were from a day-care center.
    RESULTS: Sixty-four adenovirus strains isolated in HEp2 (human laryngeal tumor cells) cells were confirmed as such by an adenovirus-group specific PCR. Nucleotide sequencing identified the following adenovirus species: A (3 isolates), B (20 isolates), C (38 isolates), D (2 isolates) and E (1 isolate). The following serotypes belonging to the species B were identified: Ad3 (1 strain), Ad7 (17 strains) and, Ad16 (2 strains).
    CONCLUSION: Other viral agents became more recognized in association with CNS diseases in areas where wild polioviruses have been eradicated. The possible role of species B adenoviruses in the etiology of AFP cases similar to that caused by wild poliovirus is discussed.
    Matched MeSH terms: Enterovirus Infections/virology*
  5. [Myocarditis caused by enteroviruses in Greece--and in Germany?]
    Braun R, Hassler D, Kimmig P
    Dtsch. Med. Wochenschr., 2002 Jun 21;127(25-26):1364.
    PMID: 12136792
    Matched MeSH terms: Enterovirus Infections/virology
  6. Enterovirus 71: the virus, its infections and outbreaks
    Ho M
    J Microbiol Immunol Infect, 2000 Dec;33(4):205-16.
    PMID: 11269363
    Enterovirus 71 (EV71) was first recognized in 1974. Since then it has been implicated in 13 small and large outbreaks world-wide. Large outbreaks of hand, foot and mouth disease (HFMD), mostly benign, occurred in Japan in 1973 and 1978. Four outbreaks with brain stem encephalitis and significant numbers of deaths occurred in Bulgaria and Hungary in the late 1970's and in Malaysia and Taiwan in 1997 and 1998 respectively. During the latter two epidemics, pulmonary edema and hemorrhage often leading to quick deaths in children aged from 0.5 to 3 years old was first recognized. In Taiwan 78 deaths and over 100,000 cases of HFMD occurred. Coxsackie A16 cocirculated with EV 71, without however, causing any severe illnesses. The transmission of EV 71 was related to number of siblings in a household, rural residence and contact with cases of HFMD. Genotype analyses show that genotypes have changed with time in the United States and Japan. Recent isolates from Japan are similar to the isolates from Malaysia and Taiwan in 1997 and 1998, respectively. Even though genotype analysis has not identified specific sequences responsible for neurovirulence, the strains causing brain stem encephalitis and pulmonary edema in the Far East are similar and have arisen since 1997. Seroepidemiological studies in Taiwan suggest that children aged from 0.5 to 4 years old are most susceptible while the rest of the population are over 50% immune. Theoretically there is a pool of such susceptible subjects every few years. In prevention for another major outbreak, a simple, inactivated Salk type vaccine should be immediately prepared and made available.
    Matched MeSH terms: Enterovirus Infections/virology
  7. Phylogenetic analysis of enterovirus 71 strains isolated during linked epidemics in Malaysia, Singapore, and Western Australia
    McMinn P, Lindsay K, Perera D, Chan HM, Chan KP, Cardosa MJ
    J Virol, 2001 Aug;75(16):7732-8.
    PMID: 11462047
    Enterovirus 71 (EV71) is a frequent cause of hand, foot, and mouth disease (HFMD) epidemics associated with severe neurological sequelae in a small proportion of cases. There has been a significant increase in EV71 epidemic activity throughout the Asia-Pacific region since 1997. Recent HFMD epidemics in this region have been associated with a severe form of brainstem encephalitis associated with pulmonary edema and high case fatality rates. In this study, we show that four genetic lineages of EV71 have been prevalent in the Asia-Pacific region since 1997, including two previously undescribed genogroups (B3 and B4). Furthermore, we show that viruses belonging to genogroups B3 and B4 have circulated endemically in Southeast Asia during this period and have been the primary cause of several large HFMD or encephalitis epidemics in Malaysia, Singapore, and Western Australia.
    Matched MeSH terms: Enterovirus Infections/virology*
  8. Fulltext Outbreaks of enterovirus 71 infection
    AbuBakar S, Chan YF, Lam SK
    N Engl J Med, 2000 Feb 3;342(5):355-6.
    PMID: 10660400 DOI: 10.1056/NEJM200002033420513
    Matched MeSH terms: Enterovirus Infections/virology
  9. Genome sequencing and phylogenetic reconstruction reveal a potential fourth rhinovirus species and its worldwide distribution
    Ng KT, Takebe Y, Kamarulzaman A, Tee KK
    Arch Virol, 2021 Jan;166(1):225-229.
    PMID: 33084935 DOI: 10.1007/s00705-020-04855-5
    Genome sequences of members of a potential fourth rhinovirus (RV) species, provisionally denoted as rhinovirus A clade D, from patients with acute respiratory infection were determined. Bayesian coalescent analysis estimated that clade D emerged around the 1940s and diverged further around 2006-2007 into two distinctive sublineages (RV-A8-like and RV-A45-like) that harbored unique "clade-defining" substitutions. Similarity plots and bootscan mapping revealed a recombination breakpoint located in the 5'-UTR region of members of the RV-A8-like sublineage. Phylogenetic reconstruction revealed the distribution of clade D viruses in the Asia Pacific region and in Europe, underlining its worldwide distribution.
    Matched MeSH terms: Enterovirus Infections/virology
  10. Fulltext Antivirals blocking entry of enteroviruses and therapeutic potential
    Anasir MI, Zarif F, Poh CL
    J Biomed Sci, 2021 Jan 15;28(1):10.
    PMID: 33451326 DOI: 10.1186/s12929-021-00708-8
    Viruses from the genus Enterovirus (EV) of the Picornaviridae family are known to cause diseases such as hand foot and mouth disease (HFMD), respiratory diseases, encephalitis and myocarditis. The capsid of EV is an attractive target for the development of direct-acting small molecules that can interfere with viral entry. Some of the capsid binders have been evaluated in clinical trials but the majority have failed due to insufficient efficacy or unacceptable off-target effects. Furthermore, most of the capsid binders exhibited a low barrier to resistance. Alternatively, host-targeting inhibitors such as peptides derived from the capsid of EV that can recognize cellular receptors have been identified. However, the majority of these peptides displayed low anti-EV potency (µM range) as compared to the potency of small molecule compounds (nM range). Nonetheless, the development of anti-EV peptides is warranted as they may complement the small-molecules in a drug combination strategy to treat EVs. Lastly, structure-based approach to design antiviral peptides should be utilized to unearth potent anti-EV peptides.
    Matched MeSH terms: Enterovirus Infections/virology
  11. Impact of genetic changes, pathogenicity and antigenicity on Enterovirus- A71 vaccine development
    Yee PTI, Laa Poh C
    Virology, 2017 06;506:121-129.
    PMID: 28384566 DOI: 10.1016/j.virol.2017.03.017
    Enterovirus-A71 (EV-A71) is an etiological agent of the hand, foot and mouth disease (HFMD). EV-A71 infection produces high fever and ulcers in children. Some EV-A71 strains produce severe infections leading to pulmonary edema and death. Although the protective efficacy of the inactivated vaccine (IV) was ≥90% against mild HFMD, there was approximately 80% protection against severe HFMD. The monovalent EV-A71 IV elicits humoral immunity but lacks long-term immunogenicity. Spontaneous mutations of the EV-A71 genome could lead to antigenicity changes and the virus may not be neutralized by antibodies elicited by the IV. A better alternative would be the live attenuated vaccine (LAV) that elicits cellular and humoral immunity. The LAV induces excellent antigenicity and chances of reversion is reduced by presence of multiple mutations which could reduce pathogenicity. Besides CV-A16, outbreaks have been caused by CV-A6 and CV-A10, hence the development of bivalent and trivalent vaccines is required.
    Matched MeSH terms: Enterovirus Infections/virology
  12. Fulltext Isolation and Identification of Inter-Species Enterovirus Recombinant Genomes
    Bentley K, Tee HK, Pearson A, Lowry K, Waugh S, Jones S, et al.
    Viruses, 2021 11 29;13(12).
    PMID: 34960659 DOI: 10.3390/v13122390
    Positive-strand RNA virus evolution is partly attributed to the process of recombination. Although common between closely genetically related viruses, such as within species of the Enterovirus genus of the Picornaviridae family, inter-species recombination is rarely observed in nature. Recent studies have shown recombination is a ubiquitous process, resulting in a wide range of recombinant genomes and progeny viruses. While not all recombinant genomes yield infectious progeny virus, their existence and continued evolution during replication have critical implications for the evolution of the virus population. In this study, we utilised an in vitro recombination assay to demonstrate inter-species recombination events between viruses from four enterovirus species, A-D. We show that inter-species recombinant genomes are generated in vitro with polymerase template-switching events occurring within the virus polyprotein coding region. However, these genomes did not yield infectious progeny virus. Analysis and attempted recovery of a constructed recombinant cDNA revealed a restriction in positive-strand but not negative-strand RNA synthesis, indicating a significant block in replication. This study demonstrates the propensity for inter-species recombination at the genome level but suggests that significant sequence plasticity would be required in order to overcome blocks in the virus life cycle and allow for the production of infectious viruses.
    Matched MeSH terms: Enterovirus Infections/virology
  13. Fulltext Characterization of Plaque Variants and the Involvement of Quasi-Species in a Population of EV-A71
    Mandary MB, Masomian M, Ong SK, Poh CL
    Viruses, 2020 Jun 17;12(6).
    PMID: 32560288 DOI: 10.3390/v12060651
    Viral plaque morphologies in human cell lines are markers for growth capability and they have been used to assess the viral fitness and selection of attenuated mutants for live-attenuated vaccine development. In this study, we investigate whether the naturally occurring plaque size variation reflects the virulence of the variants of EV-A71. Variants of two different plaque sizes (big and small) from EV-A71 sub-genotype B4 strain 41 were characterized. The plaque variants displayed different in vitro growth kinetics compared to the parental wild type. The plaque variants showed specific mutations being present in each variant strain. The big plaque variants showed four mutations I97L, N104S, S246P and N282D in the VP1 while the small plaque variants showed I97T, N237T and T292A in the VP1. No other mutations were detected in the whole genome of the two variants. The variants showed stable homogenous small plaques and big plaques, respectively, when re-infected in rhabdomyosarcoma (RD) and Vero cells. The parental strain showed faster growth kinetics and had higher viral RNA copy number than both the big and small plaque variants. Homology modelling shows that both plaque variants have differences in the structure of the VP1 protein due to the presence of unique spontaneous mutations found in each plaque variant This study suggests that the EV-A71 sub-genotype B4 strain 41 has at least two variants with different plaque morphologies. These differences were likely due to the presence of spontaneous mutations that are unique to each of the plaque variants. The ability to maintain the respective plaque morphology upon passaging indicates the presence of quasi-species in the parental population.
    Matched MeSH terms: Enterovirus Infections/virology*
  14. Recombinant human enterovirus 71 in hand, foot and mouth disease patients
    Chan YF, AbuBaker S
    Emerg Infect Dis, 2004 Aug;10(8):1468-70.
    PMID: 15496251
    Hand, foot and mouth disease (HFMD) is a common illness of infants and young children <10 years of age. It is characterized by fever, ulcers in the oral cavity, and rashes with blisters that appear on the palm and sole. The most common causal agents of HFMD are coxsackievirus A16 (CV-A16) and human enterovirus 71 (HEV71), but other enteroviruses, including CV-A5 and CV-A10, can also cause it. When caused by CV-A16 infection, it is usually a mild disease, and patients normally recover without requiring any special medical attention.
    Matched MeSH terms: Enterovirus Infections/virology
  15. Fulltext Cell and tissue tropism of enterovirus 71 and other enteroviruses infections
    Lin JY, Shih SR
    J Biomed Sci, 2014;21:18.
    PMID: 24602216 DOI: 10.1186/1423-0127-21-18
    Enterovirus 71 (EV71) is a member of Picornaviridae that causes mild and self-limiting hand, foot, and mouth disease (HFMD). However, EV71 infections can progress to polio-like paralysis, neurogenic pulmonary edema, and fatal encephalitis in infants and young children. Large EV71 outbreaks have been reported in Taiwan, China, Japan, Malaysia, Singapore, and Australia. This virus is considered a critical emerging public health threat. EV71 is an important crucial neurotropic enterovirus for which there is currently no effective antiviral drug or vaccine. The mechanism by which EV71 causes severe central nervous system complications remains unclear. The interaction between the virus and the host is vital for viral replication, virulence, and pathogenicity. SCARB2 or PSGL-1 receptor binding is the first step in the development of viral infections, and viral factors (e.g., 5' UTR, VP1, 3C, 3D, 3' UTR), host factors and environments (e.g., ITAFs, type I IFN) are also involved in viral infections. The tissue tropism and pathogenesis of viruses are determined by a combination of several factors. This review article provides a summary of host and virus factors affecting cell and tissue tropism and the pathogenesis of enteroviruses.
    Matched MeSH terms: Enterovirus Infections/virology
  16. Enterovirus 71 encephalomyelitis and Japanese encephalitis can be distinguished by topographic distribution of inflammation and specific intraneuronal detection of viral antigen and RNA
    Wong KT, Ng KY, Ong KC, Ng WF, Shankar SK, Mahadevan A, et al.
    Neuropathol. Appl. Neurobiol., 2012 Aug;38(5):443-53.
    PMID: 22236252 DOI: 10.1111/j.1365-2990.2011.01247.x
    To investigate if two important epidemic viral encephalitis in children, Enterovirus 71 (EV71) encephalomyelitis and Japanese encephalitis (JE) whose clinical and pathological features may be nonspecific and overlapping, could be distinguished.
    Matched MeSH terms: Enterovirus Infections/virology
  17. Fulltext Virucidal activity of Virkon S on human enterovirus
    Chan YF, Abu Bakar S
    Med J Malaysia, 2005 Jun;60(2):246-8.
    PMID: 16114171
    The efficacy of Virkon S, a commercial disinfectant as a virucidal spray against human enterovirus 71 (HEV71), the causative agent of the fatal form of hand, foot and mouth disease was examined. At least one log10 reduction of HEV71 titer was achieved when one spray of Virkon (1% or 2%) with ten minutes of contact time was applied. The infectivity was completely lost when four sprays of 1% or 2% Virkon were applied, suggesting that at least four sprays of 1% Virkon to the surface bound HEV71 was necessary to completely inactivate the virus. These findings suggest that Virkon S at the proper concentration is suitable to be used as an effective and easy to use disinfectant against HEV71.
    Matched MeSH terms: Enterovirus Infections/virology
  18. Fulltext Outbreaks of enterovirus D68 in Malaysia: genetic relatedness to the recent US outbreak strains
    Ng KT, Oong XY, Pang YK, Hanafi NS, Kamarulzaman A, Tee KK
    Emerg Microbes Infect, 2015 Aug;4(8):e47.
    PMID: 26421270 DOI: 10.1038/emi.2015.47
    Matched MeSH terms: Enterovirus Infections/virology
  19. Complete sequence analyses of enterovirus 71 strains from fatal and non-fatal cases of the hand, foot and mouth disease outbreak in Singapore (2000)
    Singh S, Poh CL, Chow VT
    Microbiol. Immunol., 2002;46(11):801-8.
    PMID: 12516778
    Enterovirus 71 (EV71) is a major aetiological agent of hand, foot and mouth disease (HFMD). In recent years, several outbreaks in East Asia were associated with neurological complications and numerous deaths. An outbreak in Singapore in October 2000 afflicted thousands of children, resulting in four fatal cases from three of whom EV71 was isolated. The genomes of two representative EV71 strains isolated from a fatal case and a surviving patient were completely sequenced, and their nucleotide and amino acid sequences compared with known EV71 strains. The two outbreak strains were classified under genogroup B, together with those previously isolated in Singapore, Malaysia and Japan. Comparative sequence analysis of the two Singapore strains revealed 99% nucleotide similarity, while their deduced amino acid sequences were almost identical except for residue 1506 in the 3A non-structural region. Given that the outbreak involved closely related genetic variants of EV71, the broad spectrum of disease severity may be attributed to critical factors such as varying viral inoculation doses or differing host immune responses following infection, but is less likely to be due to the emergence of EV71 strains with heightened virulence.
    Matched MeSH terms: Enterovirus Infections/virology
  20. Isolation of subgenus B adenovirus during a fatal outbreak of enterovirus 71-associated hand, foot, and mouth disease in Sibu, Sarawak
    Cardosa MJ, Krishnan S, Tio PH, Perera D, Wong SC
    Lancet, 1999 Sep 18;354(9183):987-91.
    PMID: 10501361
    In mid-1997, several children died in Sarawak, Malaysia, during an epidemic of enterovirus-71 (EV71) hand, foot, and mouth disease. The children who died had a febrile illness that rapidly progressed to cardiopulmonary failure and the cause was not satisfactorily resolved. We describe the isolation and identification of a subgenus B adenovirus from the children who died.
    Matched MeSH terms: Enterovirus Infections/virology
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