Displaying publications 1 - 20 of 73 in total

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  1. Mohamad Isa II, Abu Bakar S, Ab Rahman AK
    J Med Virol, 2020 08;92(8):1173-1181.
    PMID: 31957025 DOI: 10.1002/jmv.25680
    The impact of sociodemographic and clinical factors on immune recovery and viral load suppression among HIV-1 positive patients treated with HAART particularly in Malaysia is largely unknown. This cross-sectional study enrolled 170 HIV-1-infected individuals of three major ethnicities who attended three HIV outpatient clinics in Malaysia. Questionnaire was used to obtain sociodemographic data while CD4 count and viral load data were gathered from hospital's record. Multiple factors were assessed for their predictive effects on CD4 count recovery (≥500 cells/mm3 ) and viral load suppression (≤50 copies/mL) using binary logistic regression. Most of the subjects were male (149/87.6%), in the age group 30 to 39 years old (78/45.9%) and got infected via homosexual contact (82/48.2%). Indians were associated with 11 times higher chance for CD4 recovery as compared to Malays at 8 to 12 months of HAART (adjusted OR: 10.948, 95% CI: 1.873, 64.001, P = .008). Viral load suppression was positively influenced by intravenous drug use (IVDU) status (adjusted OR: 35.224, 95% CI: 1.234, 1000.489, P = .037) at 4 to 6 months of HAART. Higher pretreatment CD4 count was a positive predictor for both initial immunological and virological responses while higher pretreatment viral load was a negative predictor for virological suppression only. In conclusion, ethnicity plays a significant role in determining early immune reconstitution in Malaysia, besides pretreatment CD4 count. Further studies are needed to identify possible biological factors underlying this association.
  2. Yadav M, Umamaheswari S, Ablashi D
    J Med Virol, 1991 Apr;33(4):236-9.
    PMID: 1649908
    A total of 234 sera from healthy Malaysians of diverse ethnic origins were tested for antibody to the Z29 and prototype GS strains of HHV-6. The prevalence in the races ranged from 58 to 80% for the GS strain and 49 to 76% for the Z29 strain. The highest prevalence was in Malays with semi-urban cultural lifestyles and lowest was in the indigenous rural tribes (Ibans, Kadazans, Bidayuhs, and Orang Asli). The antibody titres to GS and Z29 virus capsid antigens differed in 11 (4.7%) samples by more than 2 dilutions. In 9 of the 11 sera the titres to GS strain were higher than to the Z29 strain. The differences in the antibody titres between strains of HHV-6 may reflect subtle changes in antigen structure of the virus recognised by some individuals.
  3. Chang LY, Ali AR, Hassan SS, AbuBakar S
    J Med Virol, 2006 Aug;78(8):1105-12.
    PMID: 16789019
    Nipah virus infection of porcine stable kidney cells (PS), human neuronal cells (SK-N-MC), human lung fibroblasts cells (MRC-5), and human monocytes (THP-1) were examined. Rapid progression of cytopathic effects (CPE) and cell death were noted in PS cell cultures treated with Nipah virus, followed by MRC-5, SK-N-MC, and THP-1 cell cultures, in descending order of rapidity. Significant increase in the intracellular Nipah virus RNA occurred beginning at 24 hr PI in all the infected cells. Whereas, the extracellular release of Nipah virus RNA increased significantly beginning at 48 and 72 hr PI for the infected MRC-5 cells and PS cells, respectively. No significant release of extracellular Nipah virus RNA was detected from the Nipah virus-infected SK-N-MC and THP-1 cells. At its peak, approximately 6.6 log PFU/microl of extracellular Nipah virus RNA was released from the Nipah virus-infected PS cells, with at least a 100-fold less virus RNA was recorded in the Nipah virus-infected SK-N-MC and THP-1. Approximately 15.2% (+/-0.1%) of the released virus from the infected PS cell cultures was infectious in contrast to approximately 5.5% (+/-0.7%) from the infected SK-N-MC cells. The findings suggest that there are no differences in the capacity to support Nipah virus replication between pigs and humans in fully susceptible PS and MRC-5 cells. However, there are differences between these cells and human neuronal cells and monocytes in the ability to support Nipah virus replication and virus release.
  4. Abd-Jamil J, Azizan NS, Che-Mat-Seri NA, Yaacob CN, Samsudin NI, Mahfodz NH, et al.
    J Med Virol, 2021 08;93(8):4714-4719.
    PMID: 33421159 DOI: 10.1002/jmv.26790
    Early diagnosis of dengue is important to ensure proper management of patients and effective implementation of control measures. The present study was undertaken to determine the outcome of the implementation of dengue NS1-antigen (Ag) rapid diagnostic test (RDT) in the confirmation of dengue at the first patient hospital visit at the University Malaya Medical Centre. A total of 1036 and 1097 sera from the year 2008 and 2015 were used, representing samples from before and after dengue NS1-Ag RDT was implemented as routine diagnostic at the hospital. Results showed that similar dengue confirmation percentage (56%) was made in 2008 and 2015, regardless of the main laboratory diagnostic method used. Confirmation of dengue, however, increased to 68% and 73% when dengue NS1-Ag test or dengue immunoglobulin M-capture enzyme-linked immunosorbent assay was used as the second test for the 2008 and 2015 samples, respectively. Detection of dengue virus (DENV) using multiplex reverse transcription-polymerase chain reaction (RT-PCR) showed that DENV-1 was the highest in circulation in 2008 and that both DENV-1 and DENV-2 were dominant in 2015. In summary, the present study demonstrated that the introduction and use of the dengue NS1-Ag RDT did not change or compromise confirmation of dengue, highlighting the advantage of using the method. With the reducing cost of molecular detection tools, DENV detection using RT-PCR remains a viable option for further confirmation of dengue in hospital settings.
  5. Khor CS, Mohd-Rahim NF, Hassan H, Tan KK, Zainal N, Teoh BT, et al.
    J Med Virol, 2020 08;92(8):956-962.
    PMID: 31814135 DOI: 10.1002/jmv.25649
    Dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV) are mosquito-borne flavivirus of medical importance in tropical countries such as Malaysia. However, much remains unknown regarding their prevalence among the underserved indigenous people (Orang Asli) living in communities in the forest fringe areas of Peninsular Malaysia. Information on the prevalence of diseases is necessary to elevate the effectiveness of disease control and preventive measures. This study aimed to determine the seroprevalence of the three major flaviviruses among the Orang Asli and investigate the association between demographic factors and seropositivities. Sampling activities were conducted in the Orang Asli villages to obtain serum samples and demographic data from consenting volunteers. The presence of DENV, JEV, and ZIKV immunoglobulin G (IgG) antibodies in the sera were examined using commercial enzyme-linked immunosorbent assay kits. A focus reduction neutralization assay was performed to measure virus-specific neutralizing antibodies. A total of 872 serum samples were obtained from the Orang Asli volunteers. Serological assay results revealed that DENV IgG, JEV IgG, and ZIKV IgG seropositivities among the Orang Asli were at 4.9%, 48.4%, and 13.2%, respectively. Neutralizing antibodies (FRNT50 ≥ 1:40) against JEV and ZIKV were found in 86.7% and 100.0%, respectively, out of the samples tested. Positive serology to all three viruses corresponded significantly to the age of the volunteers with increasing seropositivity in older volunteers. Findings from the study suggest that Orang Asli are at significant risk of contracting JEV and ZIKV infections despite the lack of active transmission of the viruses in the country.
  6. Rao M, Rashid FA, Sabri FSAH, Jamil NN, Seradja V, Abdullah NA, et al.
    J Med Virol, 2021 Apr;93(4):2461-2466.
    PMID: 33393672 DOI: 10.1002/jmv.26773
    An optimal clinical specimen for accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by minimizing the usage of consumables and reduce hazard exposure to healthcare workers is an urgent priority. The diagnostic performance of SARS-CoV-2 detection between healthcare worker-collected nasopharyngeal and oropharyngeal (NP + OP) swabs and patient performed self-collected random saliva was assessed. Paired NP + OP swabs and random saliva were collected and processed within 48 h of specimen collection from two cohort studies which recruited 562 asymptomatic adult candidates. Real-time reverse-transcription polymerase chain reaction targeting Open reading frame 1a (ORF1a) and nucleocapsid (N) genes was performed and the results were compared. Overall, 65 of 562 (28.1%) candidates tested positive for COVID-19 based on random saliva, NP + OP swabs, or both testing techniques. The detection rate of SARS-CoV-2 was higher in random saliva compared to NP + OP testing (92.3%; 60/65 vs. 73.8%; 48/65; p 
  7. Sawal I, Ahmad S, Tariq W, Tahir MJ, Essar MY, Ahmed A
    J Med Virol, 2021 09;93(9):5228-5230.
    PMID: 33942326 DOI: 10.1002/jmv.27031
  8. Ullah I, Hassan W, Tahir MJ, Ahmed A
    J Med Virol, 2021 Oct;93(10):5689-5690.
    PMID: 34143897 DOI: 10.1002/jmv.27134
  9. Seow HF, Mahomed NM, Mak JW, Riddell MA, Li F, Anderson DA
    J Med Virol, 1999 Oct;59(2):164-8.
    PMID: 10459151
    The prevalence of antibodies to hepatitis E virus (HEV) has been examined in many countries, but such studies have generally been limited to majority populations such as those represented in healthy blood donors or cross sections of urban populations. Due to its major route of enteric transmission, large differences in HEV prevalence might be expected between populations in the same country but with different living conditions. Using an ELISA based on GST-ORF2.1 antigen, the prevalence of IgG-class antibodies to HEV was examined in three distinct populations in Malaysia: the normal (urban) blood donor population and two aboriginal communities located at Betau, Pahang and Parit Tanjung, Perak. IgG anti-HEV was detected in 45 (44%) of 102 samples from Betau and 15 (50%) of 30 samples from Parit Tanjung, compared to only 2 (2%) of 100 normal blood donors. The distribution of sample ELISA reactivities was also consistent with ongoing sporadic infection in the aboriginal communities, while there was no significant relationship between HEV exposure and age, sex, or malaria infection. The high prevalence of antibodies to HEV in the two aboriginal communities indicates that this group of people are at high risk of exposure to HEV compared to the general blood donors, and the results suggest that studies of HEV seroprevalence within countries must take into account the possibility of widely varying infection rates between populations with marked differences in living conditions.
  10. Sam IC, Shaw R, Chan YF, Hooi PS, Hurt AC, Barr IG
    J Med Virol, 2013 Aug;85(8):1420-5.
    PMID: 23765779 DOI: 10.1002/jmv.23622
    Relatively little is known about the burden of influenza in tropical countries. The seroprevalence of pandemic influenza A (H1N1) 2009, seasonal H1N1 and H3N2 was determined in Kuala Lumpur, Malaysia. Pre- and post-pandemic residual laboratory sera were tested by hemagglutination-inhibition. The seroprevalence of A(H1N1)pdm09 increased from 3.7% pre-pandemic to 21.9% post-pandemic, giving an overall cumulative incidence of 18.1% (95% CI, 13.8-22.5%), mainly due to increases in those <5, 5-17, and 18-29 years old. In contrast with findings from USA, Europe, and Australia, pre-existing seroprevalence to A(H1N1)pdm09 was low at 5.6% in the elderly age group of >55 years. A(H1N1)pdm09 affected almost a third of those <30 years in Kuala Lumpur. Pre-pandemic seroprevalence was 14.7% for seasonal H1N1 and 21.0% for H3N2, and these rates did not change significantly after the pandemic. Seasonal and pandemic influenza cause a considerable burden in tropical Malaysia, particularly in children and young adults.
  11. Perera D, Shimizu H, Yoshida H, Tu PV, Ishiko H, McMinn PC, et al.
    J Med Virol, 2010 Apr;82(4):649-57.
    PMID: 20166171 DOI: 10.1002/jmv.21652
    The VP4, VP2, and VP1 gene regions were evaluated for their usefulness in typing human enteroviruses. Three published RT-PCR primers sets targeting separately these three gene regions were used. Initially, from a total of 86 field isolates (36 HEV-A, 40 HEV-B, and 10 HEV-C) tested, 100% concordance in HEV-A was identified from all three gene regions (VP4, VP2, and VP1). However, for HEV-B and HEV-C viruses, only the VP2 and VP1 regions, and not VP4, showed 100% concordance in typing these viruses. To evaluate further the usefulness of VP4 in typing HEV-A enteroviruses, 55 Japanese and 203 published paired VP4 and VP1 nucleotide sequences were also examined. In each case, typing by VP4 was 100% in concordance with typing using VP1. Given these results, it is proposed that for HEV-A enteroviruses, all three gene regions (VP4, VP2, and VP1), would be useful for typing these viruses. These options would enhance the capability of laboratories in identifying these viruses and would greatly help in outbreaks of hand, foot, and mouth disease.
  12. Chong YM, Tan XH, Hooi PS, Lee LM, Sam IC, Chan YF
    J Med Virol, 2019 08;91(8):1562-1565.
    PMID: 31032971 DOI: 10.1002/jmv.25495
    Rapid diagnosis of influenza is important for early treatment and institution of control measures. In developing tropical countries such as Malaysia, influenza occurs all year round, but molecular assays and conventional techniques (such as immunofluorescence and culture) for diagnosis are not widely available. Rapid influenza diagnostic tests (RIDTs) may be useful in this setting. A total of 552 fresh respiratory specimens were assessed from patients with respiratory symptoms at a teaching hospital in Kuala Lumpur, Malaysia from November 2017 to March 2018. Two digital immunoassays (DIAs), STANDARD F Influenza A/B Fluorescence Immunoassay (STANDARD F) and Sofia Influenza A + B Fluorescence Immunoassay (Sofia) and one conventional RIDT (immunochromatographic assay), SD Bioline Influenza Ag A/B/A(H1N1) Pandemic rapid test kit (SD Bioline) were evaluated in comparison with a WHO-recommended reverse transcription quantitative PCR (RT-qPCR). Of the 552 samples, influenza A virus was detected in 47 (8.5%) and influenza B virus in 7 (1.3%). The digital immunoassays STANDARD F and Sofia had significantly higher overall sensitivity rates (71.7% and 70.6%, respectively) than the conventional RIDT SD Bioline and immunofluorescence/viral culture (55.8% and 52.8%, respectively). Sensitivity rates were higher for influenza A than influenza B, and specificity rates were uniformly high, ranging from 98% to 100%. Digital readout RIDTs can be used in tropical settings with year-round influenza if PCR is unavailable.
  13. Sam IC, Noraini W, Sandhu SS, Norizah I, Selvanesan S, Thayan R, et al.
    J Med Virol, 2019 03;91(3):498-502.
    PMID: 30199092 DOI: 10.1002/jmv.25313
    Influenza seasonality in equatorial countries is little understood. Seasonal and alert influenza thresholds were determined for Malaysia, using laboratory-based data obtained from the Malaysia Influenza Surveillance System and a major teaching hospital, from 2011 to 2016. Influenza was present year-round, with no clear annual seasons. Variable periods of higher transmission occurred inconsistently, in November to December, January to March, July to September, or a combination of these. These coincide with seasons in the nearby southeast Asian countries or winter seasons of the northern and southern hemispheres. Changes in the predominant circulating influenza type were only sometimes associated with increased transmission. The data can provide public health interventions such as vaccines.
  14. Sam IC, Chong YM, Abdullah A, Fu JYL, Hasan MS, Jamaluddin FH, et al.
    J Med Virol, 2021 Nov 10.
    PMID: 34757638 DOI: 10.1002/jmv.27441
    Malaysia has experienced three waves of coronavirus disease 2019 (COVID-19) as of March 31, 2021. We studied the associated molecular epidemiology and SARS-CoV-2 seroprevalence during the third wave. We obtained 60 whole-genome SARS-CoV-2 sequences between October 2020 and January 2021 in Kuala Lumpur/Selangor and analyzed 989 available Malaysian sequences. We tested 653 residual serum samples collected between December 2020 to April 2021 for anti-SARS-CoV-2 total antibodies, as a proxy for population immunity. The first wave (January 2020) comprised sporadic imported cases from China of early Pango lineages A and B. The second wave (March-June 2020) was associated with lineage B.6. The ongoing third wave (from September 2020) was propagated by a state election in Sabah. It is due to lineage B.1.524 viruses containing spike mutations D614G and A701V. Lineages B.1.459, B.1.470, and B.1.466.2 were likely imported from the region and confined to Sarawak state. Direct age-standardized seroprevalence in Kuala Lumpur/Selangor was 3.0%. The second and third waves were driven by super-spreading events and different circulating lineages. Malaysia is highly susceptible to further waves, especially as alpha (B.1.1.7) and beta (B.1.351) variants of concern were first detected in December 2020/January 2021. Increased genomic surveillance is critical.
  15. NikNadia N, Tan CW, Ong KC, Sam IC, Chan YF
    J Med Virol, 2018 06;90(6):1164-1167.
    PMID: 29457642 DOI: 10.1002/jmv.25061
    Enterovirus A71 (EV-A71) neutralization escape mutants were generated with monoclonal antibody MAB979 (Millipore). The VP2-T141I and VP1-D14N substitutions were identified. Using reverse genetics, infectious clones with these substitutions were constructed and tested by neutralization assay with immune sera from mice and humans. The N-terminus VP1-14 is more important than EF loop VP2-141 in acute human infection, mainly because it recognised IgM present in acute infection. The N-terminus VP1 could be a useful target for diagnostics and therapeutic antibodies in acute infection.
  16. Lo Presti A, Cella E, Giovanetti M, Lai A, Angeletti S, Zehender G, et al.
    J Med Virol, 2016 Mar;88(3):380-8.
    PMID: 26252523 DOI: 10.1002/jmv.24345
    Nipah virus, member of the Paramyxoviridae family, is classified as a Biosafety Level-4 agent and category C priority pathogen. Nipah virus disease is endemic in south Asia and outbreaks have been reported in Malaysia, Singapore, India, and Bangladesh. Bats of the genus Pteropus appear to be the natural reservoir of this virus. The aim of this study was to investigate the genetic diversity of Nipah virus, to estimate the date of origin and the spread of the infection. The mean value of Nipah virus N gene evolutionary rate, was 6.5 × 10(-4) substitution/site/year (95% HPD: 2.3 × 10(-4)-1.18 × 10(-3)). The time-scaled phylogenetic analysis showed that the root of the tree originated in 1947 (95% HPD: 1888-1988) as the virus entered in south eastern Asiatic regions. The segregation of sequences in two main clades (I and II) indicating that Nipah virus had two different introductions: one in 1995 (95% HPD: 1985-2002) which correspond to clade I, and the other in 1985 (95% HPD: 1971-1996) which correspond to clade II. The phylogeographic reconstruction indicated that the epidemic followed two different routes spreading to the other locations. The trade of infected pigs may have played a role in the spread of the virus. Bats of the Pteropus genus, that are able to travel to long distances, may have contributed to the spread of the infection. Negatively selected sites, statistically supported, could reflect the stability of the viral N protein.
  17. Kalaycioglu AT, Baykal A, Guldemir D, Bakkaloglu Z, Korukluoglu G, Coskun A, et al.
    J Med Virol, 2013 Dec;85(12):2128-35.
    PMID: 23959542 DOI: 10.1002/jmv.23714
    Genetic characterization of measles viruses (MVs) combined with acquisition of epidemiologic information is essential for measles surveillance programs used in determining transmission pathways. This study describes the molecular characterization of 26 MV strains (3 from 2010, 23 from 2011) obtained from urine or throat swabs harvested from patients in Turkey. MV RNA samples (n = 26) were subjected to sequence analysis of 450 nucleotides comprising the most variable C-terminal region of the nucleoprotein (N) gene. Phylogenetic analysis revealed 20 strains from 2011 belonged to genotype D9, 3 to D4, 2 strains from 2010 to genotype D4 and 1 to genotype B3. This study represents the first report describing the involvement of MV genotype D9 in an outbreak in Turkey. The sequence of the majority of genotype D9 strains was identical to those identified in Russia, Malaysia, Japan, and the UK. Despite lack of sufficient epidemiologic information, the presence of variants observed following phylogenetic analysis suggested that exposure to genotype D9 might have occurred due to importation more than once. Phylogenetic analysis of five genotype D4 strains revealed the presence of four variants. Epidemiological information and phylogenetic analysis suggested that three genotype D4 strains and one genotype B3 strain were associated with importation. This study suggests the presence of pockets of unimmunized individuals making Turkey susceptible to outbreaks. Continuing molecular surveillance of measles strains in Turkey is essential as a means of acquiring epidemiologic information to define viral transmission patterns and determine the effectiveness of measles vaccination programs designed to eliminate this virus.
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