Displaying publications 1 - 20 of 117 in total

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  1. Wong LP, Sam IC
    Vaccine, 2010 Jun 17;28(28):4499-505.
    PMID: 20451639 DOI: 10.1016/j.vaccine.2010.04.043
    The study aimed to determine factors influencing the uptake of 2009 H1N1 influenza vaccine in a multiethnic Asian population. Population-based, cross-sectional survey was conducted between October and December 2009. Approximately 70% of overall participants indicated willingness to be vaccinated against the 2009 H1N1 influenza. Participants who indicated positive intention to vaccinate against 2009 H1N1 influenza were more likely to have favorable attitudes toward the 2009 H1N1 vaccine. A halal (acceptable to Muslims) vaccine was the main factor that determined Malay participants' decision to accept vaccination, whereas safety of the vaccine was the main factor that influenced vaccination decision for Chinese and Indian participants. The study highlights the challenges in promoting the 2009 H1N1 vaccine. Ethnic-sensitive efforts are needed to maximize acceptance of H1N1 vaccines in countries with diverse ethnic communities and religious practices.
  2. Wong LP, Sam IC
    J Behav Med, 2011 Feb;34(1):23-31.
    PMID: 20680674 DOI: 10.1007/s10865-010-9283-7
    In the setting of the new A(H1N1) outbreak, the study was conducted to assess: (1) fear of the A(H1N1) pandemic; (2) risk avoidance behavior; (3) health-protective behavior; and (4) psychosocial impact in the ethnically diverse population of Malaysia. A cross-sectional, computer-assisted telephone interview was conducted between July 11 and September 12, 2009. A total of 1,050 respondents were interviewed. Fear about the pandemic was high, with 73.2% of respondents reporting themselves as Slightly fearful/Fearful. High risk avoidance and health protective behavior were reported, with 78.0 and 99.0% reporting at least one avoidance and protective behavior respectively. Knowledge was a significant predictor for practice of healthprotective behavior across the three ethnic groups. Level of fear was significantly correlated with number of protective and avoidance behaviors. The study highlights the need for provision of accurate information that increases risk avoidance and health protective behaviors, while at the same time decreases fear or panic in the general public.
  3. Wong LP, Sam IC
    J Community Health, 2010 Dec;35(6):676-82.
    PMID: 20411411 DOI: 10.1007/s10900-010-9271-4
    Providing health information during disease outbreaks is a fundamental component of outbreak control strategies. This study aimed to explore sources of influenza A(H1N1)-related information, specific information needs and preferences of the lay public during the peak of the outbreak. A cross-sectional, population-based, computer-assisted telephone interview of 1,050 respondents was conducted in Malaysia between July 11 and September 12, 2009. Newspaper, television and family were three main sources of information about A(H1N1). There were substantial ethnic differences; the Malays were significantly more likely to identify television as main source, while newspapers and family were identified as the main sources by the Chinese and Indians, respectively. Overall, the two main information needs identified were prevention and treatment. The Malays expressed lesser need for overall information than other ethnic groups. The three most preferred sources of information were television, newspapers and healthcare providers. There were significant positive correlations between amount of information received with knowledge (r = 0.149), perceived susceptibility to infection (r = 0.177), and other behavioral responses. Health information dissemination should be dedicated to meeting the information needs of diverse sociodemographic and ethnic groups. The findings highlight the importance of providing information that increases awareness and behavioral changes in disease prevention yet reduce fear.
  4. Wong LP, Sam IC
    Prev Med, 2010 Jul;51(1):92-3.
    PMID: 20403375 DOI: 10.1016/j.ypmed.2010.04.010
    This paper aimed to examine the temporal changes in psychobehavioral responses in relation to reported 2009 H1N1 influenza deaths.
  5. Wong LP, Sam IC
    Int J Behav Med, 2011 Jun;18(2):112-21.
    PMID: 20835855 DOI: 10.1007/s12529-010-9114-9
    BACKGROUND: Assessment of general public's knowledge and attitudes toward the development and prevention of new disease outbreaks is imperative because they have profound effects on health behaviors and may contribute to the control of the epidemic.
    PURPOSE: To investigate the level of knowledge and attitudes towards the influenza A(H1N1) outbreak across various ethnic groups and socio-demographic backgrounds in Malaysia.
    METHOD: A cross-sectional, population-based, computer-assisted telephone interview exploring knowledge and attitudes regarding influenza A(H1N1) was conducted in Malaysia. Between July 11 and September 12, 2009, a total of 1,050 respondents were interviewed (response rate 69.3%).
    RESULTS: The mean total knowledge score for the overall sample was 7.30 (SD ± 1.961) out of a possible score of 13 (Chinese had the highest scores, followed by Indians, then Malays). Some erroneous beliefs about the modes of transmission were identified. The majority of the participants (73.8%) perceived the A(H1N1) infection as often deadly. Despite the overestimation of the severity of A(H1N1) infection, high confidence in preventing infection and low perceived susceptibility of infection were reported. Influenza A(H1N1)-related stigma was prevalent and exhibited differences across ethnic groups.
    CONCLUSIONS: Findings suggest that provision of education and clear information are essential to correct the misconceptions, and increase perceived susceptibility to infection so that the general public will take precautions against A(H1N1) infection.
  6. Wong LP, Sam IC
    Eur J Obstet Gynecol Reprod Biol, 2010 Jan;148(1):90-5.
    PMID: 19910102 DOI: 10.1016/j.ejogrb.2009.10.002
    OBJECTIVE:
    Cervical HPV is the most common sexually transmitted disease among college-age women. This study aimed to assess knowledge and attitudes towards HPV infection, HPV vaccination and cervical cancer among female university students, to provide insight into development of HPV educational information.

    STUDY DESIGN:
    A cross-sectional survey using a convenience sample. A total of 1083 ethnically diverse female students attending a public university were approached and 650 were interviewed.

    RESULTS:
    Knowledge regarding HPV, HPV vaccination, cervical screening and cervical cancer risk factors was remarkably poor. Across the sample, the mean total knowledge score (14-item) was only 3.25 (S.D. +/-2.41; 95% CI 3.07-3.44). Only 10.3% had heard of the newly released HPV vaccine. Approximately 48% of participants indicated an intention to receive an HPV vaccine. Intention to receive an HPV vaccine was significantly associated with knowledge of HPV and genital warts (OR 1.53; 95% CI 1.25-1.88), and knowledge of cervical screening and cervical cancer risk factors (OR 1.21; 95% CI 1.11-1.33). Of those who refused HPV vaccination, 50.9% doubted the safety and efficacy of the new vaccine, and 41.5% perceived themselves as not at risk of HPV infection.

    CONCLUSION:
    The findings suggest that providing education about the etiology of cervical cancer and the HPV link is an essential component to enhance HPV vaccine uptake.
  7. Sam IC, Abu Bakar S
    Med J Malaysia, 2009 Jun;64(2):105-7.
    PMID: 20058566
    In recent years, zoonotic RNA viruses such as Nipah, SARS coronavirus, avian influenza (H5N1) and Chikungunya have emerged with global impact. The latest has now been designated by World Health Organization (WHO) as pandemic (H1N1) 2009 virus. It was first reported as an outbreak in Mexico in April, and has now caused the first influenza pandemic since 1968. By July 11, 2009, there were 105,304 confirmed cases and 463 deaths in 143 countries, including 627 cases in Malaysia1 . The rapid spread of the disease has been matched by the speed of dissemination of information and protocols, co-ordinated by WHO. The experiences of SARS and H5N1 have been enormously beneficial in preparing the world for a pandemic.
  8. Wong LP, Sam IC
    Malays Fam Physician, 2007;2(2):47-53.
    PMID: 25606080 MyJurnal
    Certain human papillomavirus (HPV) types are strongly associated with cervical cancer. Recently-described effective vaccines against these HPV types represent a great medical breakthrough in preventing cervical cancer. In Malaysia, the vaccine has just received regulatory approval. We are likely to face similar barriers to implementing HPV vaccination as reported by countries where vaccination has been introduced. Most women have poor understanding of HPV and its link to cervical cancer. Physicians who will be recommending HPV vaccines may not have extensive knowledge or experience with HPV-related disease. Furthermore, a vaccine against a sexually-transmitted infection may elicit negative reactions from potential recipients or their carers, particularly in a conservative society. Given the high cost of the vaccine, reaching the most vulnerable women is a concern. To foster broad acceptance of HPV vaccine, education must be provided to health care providers, parents and young women about the risks of HPV infection and the benefits of vaccination.
  9. Sam IC, Puthucheary SD
    Ann Trop Paediatr, 2006 Sep;26(3):219-24.
    PMID: 16925959
    There are few data on paediatric melioidosis in endemic areas outside rural north-eastern Thailand and northern Australia. This study reports 16 culture-confirmed cases of melioidosis in children aged < or = 15 years seen between 1976 and 2005 at an urban teaching hospital in Kuala Lumpur, Malaysia. Seven (43.8%) patients had septicaemic melioidosis (with three known deaths) and nine (56.2%) had localised disease (one death). Eleven (68.8%) patients had underlying diseases, including five with haematological malignancies. Skin, soft tissue and lymph nodes were most commonly affected. There were no cases of parotitis or pharyngocervical disease (seen in Thailand), or encephalomyelitis (seen in Australia). The differences in disease seen in this study compared with the mostly rural patients described in previous studies might be owing to a different patient population in an urban environment. Septicaemic melioidosis has a high mortality, but localised disease has a good prognosis, and selected cases may be cured without the full recommended treatment regimen.
  10. Sam IC, Sulaiman AB
    Med J Malaysia, 2006 Jun;61(2):264-9.
    PMID: 16898330 MyJurnal
    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus which causes epidemic fever, rash and polyarthralgia in Africa and Asia. Two outbreaks have been reported in Malaysia, in Klang, Selangor (1998) and Bagan Panchor, Perak (2006). It is not known if the outbreaks were caused by the recent introduction of CHIKV, or if the virus was already circulating in Malaysia. Seroprevalence studies from the 1960s suggested previous disease activity in certain parts of the country. In Asia, CHIKV is thought to be transmitted by the same mosquitoes as dengue, Aedes aegypti and Ae. albopictus. Due to similarities in clinical presentation with dengue, limited awareness, and a lack of laboratory diagnostic capability, CHIKV is probably often underdiagnosed or misdiagnosed as dengue. Treatment is supportive. The prognosis is generally good, although some patients experience chronic arthritis. With no vaccine or antiviral available, prevention and control depends on surveillance, early identification of outbreaks, and vector control. CHIKV should be borne in mind in sporadic cases, and in patients epidemiologically linked to ongoing local or international outbreaks or endemic areas.
  11. Sam IC, Puthucheary SD
    J Infect, 2007 May;54(5):519-20.
    PMID: 16965821
  12. 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.
  13. Chua CL, Sam IC, Chan YF
    Methods Mol Biol, 2016;1426:51-61.
    PMID: 27233260 DOI: 10.1007/978-1-4939-3618-2_5
    Chikungunya virus (CHIKV) is a mosquito-borne arbovirus which poses a major threat to global public health. Definitive CHIKV diagnosis is crucial, especially in distinguishing the disease from dengue virus, which co-circulates in endemic areas and shares the same mosquito vectors. Laboratory diagnosis is mainly based on serological or molecular approaches. The E2 glycoprotein is a good candidate for serological diagnosis since it is the immunodominant antigen during the course of infection, and reacts with seropositive CHIKV sera. In this chapter, we describe the generation of stable clone Sf9 (Spodoptera frugiperda) cells expressing secreted, soluble, and native recombinant CHIKV E2 glycoprotein. We use direct plasmid expression in insect cells, rather than the traditional technique of generating recombinant baculovirus. This recombinant protein is useful for serological diagnosis of CHIKV infection.
  14. Chua CL, Chan YF, Sam IC
    J Virol Methods, 2014 Jan;195:126-33.
    PMID: 24134938 DOI: 10.1016/j.jviromet.2013.10.015
    Chikungunya virus (CHIKV) is a mosquito-borne arbovirus which has recently re-emerged globally and poses a major threat to public health. Infection leads to severe arthralgia, and disease management remains supportive in the absence of vaccines and anti-viral interventions. The high specificities of monoclonal antibodies (mAbs) have been exploited in immunodiagnostics and immunotherapy in recent decades. In this study, eight different clones of mAbs were generated and characterised. These mAbs targeted the linear epitopes on the CHIKV E2 envelope glycoprotein, which is the major target antigen during infection. All the mAbs showed binding activity against the purified CHIKV virion or recombinant E2 when analysed by immunofluorescence, ELISA and Western blot. The epitopes of each mAb were mapped by overlapping synthetic peptide-based ELISA. The epitopes are distributed at different functional domains of E2 glycoprotein, namely at domain A, junctions of β-ribbons with domains A and B, and domain C. Alignment of mAb epitope sequences revealed that some are well-conserved within different genotypes of CHIKV, while some are identical to and likely to cross-react with the closely-related alphavirus O'nyong-nyong virus. These mAbs with their mapped epitopes are useful for the development of diagnostic or research tools, including immunofluorescence, ELISA and Western blot.
  15. Sam IC, See KH, Puthucheary SD
    J Clin Microbiol, 2009 May;47(5):1556-8.
    PMID: 19297597 DOI: 10.1128/JCM.01657-08
    A patient with a clonal infection of Burkholderia pseudomallei had subpopulations with ceftazidime and amoxicillin-clavulanate susceptibilities that differed among the clinical specimens. Resistance was associated with a novel Cys69Tyr substitution in the Ambler class A beta-lactamase. Susceptibility testing of multiple colony variants from different sites should be performed for patients with culture-confirmed melioidosis.
  16. Tan CW, Lai JK, Sam IC, Chan YF
    J Biomed Sci, 2014;21:14.
    PMID: 24521134 DOI: 10.1186/1423-0127-21-14
    Enterovirus 71 (EV-71) is the main etiological agent of hand, foot and mouth disease (HFMD). Recent EV-71 outbreaks in Asia-Pacific were not limited to mild HFMD, but were associated with severe neurological complications such as aseptic meningitis and brainstem encephalitis, which may lead to cardiopulmonary failure and death. The absence of licensed therapeutics for clinical use has intensified research into anti-EV-71 development. This review highlights the potential antiviral agents targeting EV-71 attachment, entry, uncoating, translation, polyprotein processing, virus-induced formation of membranous RNA replication complexes, and RNA-dependent RNA polymerase. The strategies for antiviral development include target-based synthetic compounds, anti-rhinovirus and poliovirus libraries screening, and natural compound libraries screening. Growing knowledge of the EV-71 life cycle will lead to successful development of antivirals. The continued effort to develop antiviral agents for treatment is crucial in the absence of a vaccine. The coupling of antivirals with an effective vaccine will accelerate eradication of the disease.
  17. Tan CW, Poh CL, Sam IC, Chan YF
    J Virol, 2013 Jan;87(1):611-20.
    PMID: 23097443 DOI: 10.1128/JVI.02226-12
    Enterovirus 71 (EV-71) infections are usually associated with mild hand, foot, and mouth disease in young children but have been reported to cause severe neurological complications with high mortality rates. To date, four EV-71 receptors have been identified, but inhibition of these receptors by antagonists did not completely abolish EV-71 infection, implying that there is an as yet undiscovered receptor(s). Since EV-71 has a wide range of tissue tropisms, we hypothesize that EV-71 infections may be facilitated by using receptors that are widely expressed in all cell types, such as heparan sulfate. In this study, heparin, polysulfated dextran sulfate, and suramin were found to significantly prevent EV-71 infection. Heparin inhibited infection by all the EV-71 strains tested, including those with a single-passage history. Neutralization of the cell surface anionic charge by polycationic poly-d-lysine and blockage of heparan sulfate by an anti-heparan sulfate peptide also inhibited EV-71 infection. Interference with heparan sulfate biosynthesis either by sodium chlorate treatment or through transient knockdown of N-deacetylase/N-sulfotransferase-1 and exostosin-1 expression reduced EV-71 infection in RD cells. Enzymatic removal of cell surface heparan sulfate by heparinase I/II/III inhibited EV-71 infection. Furthermore, the level of EV-71 attachment to CHO cell lines that are variably deficient in cell surface glycosaminoglycans was significantly lower than that to wild-type CHO cells. Direct binding of EV-71 particles to heparin-Sepharose columns under physiological salt conditions was demonstrated. We conclude that EV-71 infection requires initial binding to heparan sulfate as an attachment receptor.
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