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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
Identification of enterovirus 71 isolates from an outbreak of hand, foot and mouth disease (HFMD) with fatal cases of encephalomyelitis in Malaysia

AbuBakar S, Chee HY, Al-Kobaisi MF, Xiaoshan J, Chua KB, Lam SK

Virus Res, 1999 May;61(1):1-9.
PMID: 10426204

Thirteen enterovirus 71 (EV71) isolates were obtained from both fatal and non-fatal infections of patients seen in Peninsula Malaysia and in Sarawak during an outbreak of hand, foot and mouth disease (HFMD) in Malaysia in 1997, with incidences of fatal brainstem encephalomyelitis. The isolates were identified using immunofluorescence staining, neutralization assays, and partial sequencing of the 5' untranslated regions (UTR). Assessment of the potential genetic relationships of the isolates using the partial 5'UTR sequences suggested clustering of the isolates into at least two main clusters. Isolates from Peninsula Malaysia were found in both clusters whereas Sarawak-derived isolates clustered only in cluster II. Isolates derived from fatal infections, however, occurred in both clusters and no distinctive nucleotide sequences could be attributed to the fatal isolates. Examination of the nucleotide sequences revealed at least 13 nucleotide positions in all the isolates which differ completely from the previously reported EV71 5'UTR sequences. In addition, at least 11 nucleotide position differences within the 5'UTR were noted which differentiated cluster I from cluster II. Predicted secondary RNA structures drawn using the nucleotide sequences also suggested differences between isolates from the two clusters. These findings suggest the presence of at least two potentially virulent EV71 co-circulating in Malaysia during the 1997 HFMD outbreak.
Molecular detection of enteroviruses from an outbreak of hand, foot and mouth disease in Malaysia in 1997

Abubakar S, Chee HY, Shafee N, Chua KB, Lam SK

Scand. J. Infect. Dis., 1999;31(4):331-5.
PMID: 10528868

Enterovirus 5'UTR sequences were detected by RT-PCR in 22 out of 47 suspected hand, foot and mouth disease (HFMD) patients during an outbreak of the disease with incidences of fatal brainstem encephalomyelitis in Malaysia in 1997. Genetic and phylogenetic analyses of the isolates 5'UTR sequences suggest the presence of predominantly enteroviruses with high sequence similarities to Echovirus 1 and Coxsackievirus A9 in the Malaysian peninsula. No fatal cases, however, were associated with these isolates. The remaining isolates, including all (4/4) isolates of the fatal cases from the Malaysian peninsula and Sarawak shared very high sequence identity with enterovirus 71MS (EV71). These findings suggest that several enteroviruses were circulating in Malaysia during the outbreak period, with only EV71 causing fatal infections.
Fulltext Second malignant neoplasms: an increasingly recognized complication of childhood cancer

Ariffin H, Ariffin WA, Chan LL, Lam SK, Lin HP

Med J Malaysia, 1997 Jun;52(2):174-7.
PMID: 10968078

Second malignant neoplasms (SMN) are an increasingly recognized late complication seen in childhood cancer survivors. A total of 3 cases of SMN have been found in the Department of Paediatrics, University Hospital Kuala Lumpur after a 15-year experience of treating childhood malignancies. Two cases are described here. The first developed abdominal non-Hodgkin's lymphoma 3 years after undergoing an allogeneic bone marrow transplant for second relapse of acute lymphoblastic leukaemia, while the second child developed myeloid leukaemia two years after completing treatment for acute lymphoblastic leukaemia. Progress in the management of childhood cancer in Malaysia and the availability of bone marrow transplantation facilities have increased the number of childhood cancer survivors; leading to increased incidence of SMN.
Validation of the Iranian/Persian Version of the Perceived Therapeutic Efficacy Scale for Type 2 Diabetes

Azami G, Lam SK, Shariff-Ghazali S, Said SM, Aazami S, Mozafari M, et al.

Arch Iran Med, 2018 08 01;21(8):356-361.
PMID: 30113857

BACKGROUND: The theory if self-efficacy is the central concept of social cognitive theory with emphasis on the constructs of efficacy expectation, outcome expectation. Efficacy expectation is defined as the person's confidence to carry out a specific behavior. Outcome expectation is beliefs that carrying out a specific behavior will lead to a specific outcome. While the benefit of measuring outcome expectations has been established, there has been no large scale within the Iranian context. The purpose of this study is to examine the reliability-validity of the Persian version of the Perceived Therapeutic Efficacy Scale (PTES).
METHODS: This study was conducted among 160 patients with type 2 diabetes mellitus (T2DM) using a self-administered instrument measuring outcome expectation. We used a methodological study design to assess the validity and reliability of the translated Persian version of the instrument.
RESULTS: The findings of the present study support the uni-dimensionality of the Persian version of the instrument. The 10 items of the scale account for 73.54% of the total variance and the un-rotated factor loadings ranged from 0.66 to 0.93. Moreover, this study offers support for convergent validity and internal consistency of the scale.
CONCLUSION: Our study demonstrated good convergent validity, factor structure and internal consistency in a sample of 160 Iranian adults with T2DM. Therefore, the Persian version of the scale is a valid and reliable instrument and can be used in research and clinical settings.
Fulltext Statement in support of the scientists, public health professionals, and medical professionals of China combatting COVID-19

Calisher C, Carroll D, Colwell R, Corley RB, Daszak P, Drosten C, et al.

Lancet, 2020 03 07;395(10226):e42-e43.
PMID: 32087122 DOI: 10.1016/S0140-6736(20)30418-9
Fulltext Science, not speculation, is essential to determine how SARS-CoV-2 reached humans

Calisher CH, Carroll D, Colwell R, Corley RB, Daszak P, Drosten C, et al.

Lancet, 2021 Jul 17;398(10296):209-211.
PMID: 34237296 DOI: 10.1016/S0140-6736(21)01419-7
Fulltext Mental Fatigue and Basketball Performance: A Systematic Review

Cao S, Geok SK, Roslan S, Sun H, Lam SK, Qian S

Front Psychol, 2021;12:819081.
PMID: 35082736 DOI: 10.3389/fpsyg.2021.819081

Mental fatigue (MF) is a psycho-biological state that impairs sports-related performances. Recently, it has been proved that MF can affect basketball performance. However, a systematic overview detailing the influences of MF on basketball performance is still lacking. This study aims to investigate the effects of MF on the physical, technical, tactical, and cognitive performance of basketball. We used the databases of PubMed, Web of Science, SPORTDiscus, Scopes, and CKNI for articles published up to 31 May 2021. The articles included in this study were projected to test whether MF influences basketball athlete performance. Only experimental design studies were selected, and the control condition was without MF. Finally, seven articles fit the inclusion criteria. The results imply that MF impairs the technical aspects of basketball (free throws, three-point shots, and total turnover) and the players' cognitive [take-the-first (TTF) heuristics and decision-making] performance, which results in athletes not using their techniques skillfully and being unable to make practical decisions during critical points in the game. In addition to that, the influences of MF on physical and tactical performance have not been studied. Further studies should look into comprehensive research on the influences of MF on basketball performance, especially on a player's physical and tactical performance. Systematic Review Registration: [https://inplasy.com/] [INPLASY2021100017].
Fulltext Detection and serotyping of dengue viruses by PCR: a simple, rapid method for the isolation of viral RNA from infected mosquito larvae

Chan SY, Kautner I, Lam SK

Southeast Asian J. Trop. Med. Public Health, 1994 Jun;25(2):258-61.
PMID: 7855637

Dengue viruses pose a considerable global public health problem with an estimated 100 million cases of illness every year. This illustrates the need for rapid and reliable diagnostic methods for proper patient management and disease control. Currently, laboratory diagnosis depends on serology or virus isolation, with both methods having certain drawbacks. Alternatively, reverse transcription and polymerase chain reaction (RT-PCR) offers the potential for the rapid, highly sensitive and specific detection of dengue viruses. Since we occasionally encounter the problem of insufficient amounts of patient serum for the direct detection of dengue viruses, a method was developed for the extraction of viral RNA after biological amplification in mosquito larvae. Using this method, 15 of 19 clinical samples tested were correctly identified using RT-PCR.
The influence of antibody levels in dengue diagnosis by polymerase chain reaction

Chan SY, Kautner IM, Lam SK

J Virol Methods, 1994 Oct;49(3):315-22.
PMID: 7868649

The potential of RT-PCR to rapidly diagnose dengue infections from both acute and convalescent phase patients' sera was evaluated. The RNA extraction method involved binding of the viral RNA to silica particles in the presence of high concentration of guanidine thiocyanate. The protocol that was established was sensitive enough to detect 40 plaque forming units per 100 microliter of serum and results could be obtained within one day. Results from this study indicate that clinical samples should be collected in the early acute phase of illness when anti-dengue antibodies were undetectable or of low titres to ensure a more reliable diagnosis.
Complete nucleotide sequences of Nipah virus isolates from Malaysia

Chan YP, Chua KB, Koh CL, Lim ME, Lam SK

J Gen Virol, 2001 Sep;82(Pt 9):2151-5.
PMID: 11514724

We have completely sequenced the genomes of two Nipah virus (NiV) isolates, one from the throat secretion and the other from the cerebrospinal fluid (CSF) of the sole surviving encephalitic patient with positive CSF virus isolation in Malaysia. The two genomes have 18246 nucleotides each and differ by only 4 nucleotides. The NiV genome is 12 nucleotides longer than the Hendra virus (HeV) genome and both genomes have identical leader and trailer sequence lengths and hexamer-phasing positions for all their genes. Both NiV and HeV are also very closely related with respect to their genomic end sequences, gene start and stop signals, P gene-editing signals and deduced amino acid sequences of nucleocapsid protein, phosphoprotein, matrix protein, fusion protein, glycoprotein and RNA polymerase. The existing evidence demonstrates a clear need for the creation of a new genus within the subfamily Paramyxovirinae to accommodate the close similarities between NiV and HeV and their significant differences from other members of the subfamily.
Mapping of domains responsible for nucleocapsid protein-phosphoprotein interaction of Henipaviruses

Chan YP, Koh CL, Lam SK, Wang LF

J Gen Virol, 2004 Jun;85(Pt 6):1675-1684.
PMID: 15166452 DOI: 10.1099/vir.0.19752-0

Hendra virus (HeV) and Nipah virus (NiV) are members of a new genus, Henipavirus, in the family paramyxoviridae. Each virus encodes a phosphoprotein (P) that is significantly larger than its counterparts in other known paramyxoviruses. The interaction of this unusually large P with its nucleocapsid protein (N) was investigated in this study by using recombinant full-length and truncated proteins expressed in bacteria and a modified protein-blotting protein-overlay assay. Results from our group demonstrated that the N and P of both viruses were able to form not only homologous, but also heterologous, N-P complexes, i.e. HeV N was able to interact with NiV P and vice versa. Deletion analysis of the N and P revealed that there were at least two independent N-binding sites on P and they resided at the N and C termini, respectively. Similarly, more than one P-binding site was present on N and one of these was mapped to a 29 amino acid (aa) C-terminal region, which on its own was sufficient to interact with the extreme C-terminal 165 aa region of P.
Fulltext Optimum age for measles immunization in Malaysia

Chen ST, Lam SK

Med J Malaysia, 1985 Dec;40(4):281-8.
PMID: 3842727

A study was carried out at the University Hospital, Kuala Lumpur, Malaysia to determine the age-specific prevalence of measles infection by serology and the age specific - seroconversion rates following measles vaccination. The results show that the percentage of children with passively acquired measles antibodies decreased with increasing age fill three to five months of age. From 12 months of age, the percentage of positivity increased sharply due probably to natural infection. The geometric mean antibody titre was low at birth, but from six months it started to increase. These results indicate that measles infection is common in Malaysia and a small number of children began to acquire natural measles infection from six to eight months of age; however the peak age for the acquisition of measles infection was from 12 months to five years of age. Seroconversion rates following vaccination from nine months of age, ranged from 94-99%. However, the rates and the geometric mean titre were higher among those vaccinated at 11 months of age or older compared with those vaccinated at nine or ten months of age. Based on the above results, it is concluded that the optimum age for measles immunization in Malaysia should be 11 months.
Protocol for out-patient management of dengue illness in young adults

Chin CK, Kang BH, Liew BK, Cheah PC, Nair R, Lam SK

J Trop Med Hyg, 1993 Aug;96(4):259-63.
PMID: 8345549

A prospective study on the practicality of an out-patient management protocol for dengue infection in adults was carried out during a 2-month period. Doctors were requested to follow the protocol and assessment was done on the patients' outcome, the admission rate, and the compliance to the protocol by doctors and patients. One hundred and sixty-two patients (mean age 27.3 years) were clinically diagnosed to have dengue illness. Among them, 82.7% had dengue fever (DF); 13.0% had dengue haemorrhagic fever (DHF) and 4.3% had dengue shock syndrome (DSS). Dengue aetiology was confirmed in 69.4% of the DF group and 85.7% of the DHF and DSS groups. There were no deaths among the 162 patients. The admission rate was 43.8%. A high compliance rate of 86.4% by the doctors and a low patient default rate of 16.4% showed that the protocol was practical.
Treatment of acute Nipah encephalitis with ribavirin

Chong HT, Kamarulzaman A, Tan CT, Goh KJ, Thayaparan T, Kunjapan SR, et al.

Ann Neurol, 2001 Jun;49(6):810-3.
PMID: 11409437

Nipah virus, a newly identified paramyxovirus caused a severe outbreak of encephalitis in Malaysia with high fatalities. We report an open-label trial of ribavirin in 140 patients, with 54 patients who were managed prior to the availability of ribavirin or refused treatment as control. There were 45 deaths (32%) in the ribavirin arm; 29 deaths (54%) occurred in the control arm. This represents a 36% reduction in mortality (p = 0.011). There was no associated serious side effect. This study suggests that ribavirin is able to reduce the mortality of acute Nipah encephalitis.
Comparison of the complete nucleotide sequences of echovirus 7 strain UMMC and the prototype (Wallace) strain demonstrates significant genetic drift over time

Chua BH, McMinn PC, Lam SK, Chua KB

J Gen Virol, 2001 Nov;82(Pt 11):2629-39.
PMID: 11602774

The complete nucleotide sequences are reported of two strains of echovirus 7, the prototype Wallace strain (Eo7-Wallace) and a recent Malaysian strain isolated from the cerebrospinal fluid of a child with fatal encephalomyelitis (Eo7-UMMC strain). The molecular findings corroborate the serological placement of the UMMC strain as echovirus 7. Both Eo7-Wallace and Eo7-UMMC belong to the species human enterovirus B and are most closely related to echovirus 11. Eo7-UMMC has undergone significant genetic drift from the prototype strain in the 47 years that separate the isolation of the two viruses. Phylogenetic analysis revealed that Eo7-UMMC did not arise from recombination with another enterovirus serotype. The molecular basis for the severely neurovirulent phenotype of Eo7-UMMC remains unknown. However, it is shown that mutations in the nucleotide sequence of the 5' untranslated region (UTR) of Eo7-UMMC result in changes to the putative structure of the 5' UTR. It is possible that these changes contribute to the neurovirulence of Eo7-UMMC.
Fulltext Isolation and identification of human herpesvirus 7 from an infant with exanthem subitum

Chua KB, Lam SK, AbuBakar S

Med J Malaysia, 1998 Sep;53(3):296-301.
PMID: 10968172

Exanthem subitum (ES) is a common childhood exanthematous disease. In a recent study of ES due to human herpesvirus 6 (HHV 6), we isolated human herpesvirus 7 (HHV 7) from the peripheral blood mononuclear cells (PBMC) of a seven month-old infant with typical symptoms of ES. The identity of the virus was confirmed by indirect immunofluorescence using HHV 7 specific monoclonal antibody and by amplification of the HHV 7 specific genomic sequences using the polymerase chain reaction (PCR). Paired serum samples from the infant showed serological conversion to the isolated virus. The clinical manifestations of ES in this infant appeared to be milder than the classical ES due to HHV 6.
Full length genome sequence of Tioman virus, a novel paramyxovirus in the genus Rubulavirus isolated from fruit bats in Malaysia

Chua KB, Wang LF, Lam SK, Eaton BT

Arch Virol, 2002 Jul;147(7):1323-48.
PMID: 12111411

A novel paramyxovirus in the genus Rubulavirus, named Tioman virus (TiV), was isolated in 1999 from a number of pooled urine samples of Island Flying Foxes (Pteropus hypomelanus) during the search for the reservoir host of Nipah virus. TiV is antigenically related to Menangle virus (MenV) that was isolated in Australia in 1997 during disease outbreak in pigs. Sequence analysis of the full length genome indicated that TiV is a novel member of the genus Rubulavirus within the subfamily Paramyxovirinae, family Paramyxoviridae. However, there are several features of TiV which make it unique among known paramyxoviruses and rubulaviruses in particular: (1) TiV, like MenV, uses the nucleotide G as a transcriptional initiation site, rather than the A residue used by all other known paramyxoviruses; (2) TiV uses C as the +1 residue for all intergenic regions, a feature not seen for rubulaviruses but common for all other members within the subfamily Paramyxovirinae; (3) Although the attachment protein of TiV has structural features that are conserved in other rubulaviruses, it manifests no overall sequence homology with members of the genus, lacks the sialic acid-binding motif N-R-K-S-C-S and has only two out of the six highly conserved residues known to be important for the catalytic activity of neuraminidase.
Isolation of Nipah virus from Malaysian Island flying-foxes

Chua KB, Koh CL, Hooi PS, Wee KF, Khong JH, Chua BH, et al.

Microbes Infect., 2002 Feb;4(2):145-51.
PMID: 11880045

In late 1998, Nipah virus emerged in peninsular Malaysia and caused fatal disease in domestic pigs and humans and substantial economic loss to the local pig industry. Surveillance of wildlife species during the outbreak showed neutralizing antibodies to Nipah virus mainly in Island flying-foxes (Pteropus hypomelanus) and Malayan flying-foxes (Pteropus vampyrus) but no virus reactive with anti-Nipah virus antibodies was isolated. We adopted a novel approach of collecting urine from these Island flying-foxes and swabs of their partially eaten fruits. Three viral isolates (two from urine and one from a partially eaten fruit swab) that caused Nipah virus-like syncytial cytopathic effect in Vero cells and stained strongly with Nipah- and Hendra-specific antibodies were isolated. Molecular sequencing and analysis of the 11,200-nucleotide fragment representing the beginning of the nucleocapsid gene to the end of the glycoprotein gene of one isolate confirmed the isolate to be Nipah virus with a sequence deviation of five to six nucleotides from Nipah virus isolated from humans. The isolation of Nipah virus from the Island flying-fox corroborates the serological evidence that it is one of the natural hosts of the virus.
The presence of Nipah virus in respiratory secretions and urine of patients during an outbreak of Nipah virus encephalitis in Malaysia

Chua KB, Lam SK, Goh KJ, Hooi PS, Ksiazek TG, Kamarulzaman A, et al.

J Infect, 2001 Jan;42(1):40-3.
PMID: 11243752

To study the excretion of Nipah virus in the upper respiratory secretions and urine of infected patients in relation to other clinical features.

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