Displaying publications 1 - 20 of 165 in total

  1. Dhurga DB, Suresh KG, Tan TC, Chandramathi S
    Trans. R. Soc. Trop. Med. Hyg., 2012 Dec;106(12):725-30.
    PMID: 23141370 DOI: 10.1016/j.trstmh.2012.08.005
    Previous studies have shown that apoptosis-like features are observed in Blastocystis spp., an intestinal protozoan parasite, when exposed to the cytotoxic drug metronidazole (MTZ). This study reports that among the four subtypes of Blastocystis spp. investigated for rate of apoptosis when treated with MTZ, subtype 3 showed the highest significant increase after 72h of in vitro culture when treated with MTZ at 0.1mg/ml (79%; p<0.01) and 0.0001mg/ml (89%; p<0.001). The close correlation between viable cells and apoptotic cells for both dosages implies that the pathogenic potential of these isolates has been enhanced when treated with MTZ. This suggests that there is a mechanism in Blastocystis spp. that actually regulates the apoptotic process to produce higher number of viable cells when treated. Apoptosis may not just be programmed cell death but instead a mechanism to increase the number of viable cells to ensure survival during stressed conditions. The findings of the present study have an important contribution to influence chemotherapeutic approaches when developing drugs against the emerging Blastocystis spp. infections.
  2. Leong PK, Tan NH, Fung SY, Sim SM
    Trans. R. Soc. Trop. Med. Hyg., 2012 Dec;106(12):731-7.
    PMID: 23062608 DOI: 10.1016/j.trstmh.2012.07.009
    Cross neutralisation of venoms by antivenom raised against closely-related species has been well documented. The spectrum of paraspecific protection of antivenom raised against Asiatic Naja and Bungarus (krait) venoms, however, has not been fully investigated. In this study, we examined the cross neutralisation of venoms from common Southeast Asian cobras and kraits by two widely used polyvalent antivenoms produced in India: Vins Polyvalent Antivenom (VPAV) and Bharat Polyvalent Antivenom (BPAV), using both in vitro and in vivo mouse protection assays. BPAV was only moderately effective against venoms of N. kaouthia (Thailand) and N. sumatrana, and either very weakly effective or totally ineffective against the other cobra and krait venoms. VPAV, on the other hand, neutralised effectively all the Southeast Asian Naja venoms tested, as well as N. naja, B. candidus and Ophiophagus hannah venoms, but the potency ranges from effective to weakly effective. In an in vivo rodent model, VPAV also neutralised the lethality of venoms from Asiatic Naja and B. candidus. In anesthetised rat studies, both antivenoms effectively protected against the N. kaouthia venom-induced cardio-respiratory depressant and neuromuscular blocking effects. Overall, our results suggest that VPAV could be used as alternative antivenom for the treatment of elapid envenomation in Southeast Asian regions including Malaysia, Thailand and certain regions of Indonesia.
  3. Naing C, Mak JW, Aung K, Wong JY
    Trans. R. Soc. Trop. Med. Hyg., 2013 Feb;107(2):65-73.
    PMID: 23222952 DOI: 10.1093/trstmh/trs019
    The present review aimed to synthesise available evidence on the efficacy of dihydroartemisinin-piperaquine (DP) in treating uncomplicated Plasmodium falciparum malaria in people living in malaria-endemic countries by performing a meta-analysis of relevant studies. We searched relevant studies in electronic data bases up to December 2011. Published results from randomised controlled trials (RCTs) comparing efficacy of DP with other artemisinin-based combination therapies (ACTs), or non-ACTs, or placebo were selected. The primary endpoint was 28-day and 42-day treatment failure. We identified 26 RCTs. Many of the studies included in the present review were of high quality. Overall, DP, artesunate-mefloquine (MAS3) and artemether-lumefentrine (AL) were equally effective for reducing the risk of recurrent parasitaemia. The PCR confirmed efficacy of DP (99.5%) and MAS3 (97.7%) at day 28 exceeded 90%; both are efficacious. Comparable efficacy was also found for DP (95.6%) and AL (94.3%). The present review has documented that DP is comparable to other currently used ACTs such as MAS3 and AL in treating uncomplicated falciparum malaria. The better safety profile of DP and once-daily dosage improves adherence and its fixed co-formulation ensures that both drugs are taken together. Our conclusion is that DP has the potential to become a first-line antimalarial drug.
  4. Che Dom N, Faiz Madzlan M, Nadira Yusoff SN, Hassan Ahmad A, Ismail R, Nazrina Camalxaman S
    Trans. R. Soc. Trop. Med. Hyg., 2016 Apr;110(4):237-45.
    PMID: 27076510 DOI: 10.1093/trstmh/trw015
    Dengue fever (DF) is an urban vector-borne disease transmitted by Aedes aegypti and Aedes albopictus. Both species deposit their eggs in favorable breeding sites either in natural or artificial containers. An understanding of their habitat characteristics is crucial in curbing DF outbreaks
  5. Naing C, Kassim AI
    Trans. R. Soc. Trop. Med. Hyg., 2012 Jun;106(6):331-2.
    PMID: 22541873 DOI: 10.1016/j.trstmh.2012.03.003
    Studies have reported that only a small fraction of fever cases in malaria-endemic areas are actually caused by malaria. Much greater emphasis is now needed to step up attention to the appropriate management of nonmalarial acute undifferentiated febrile illness. There is an overlap at the start of clinical manifestations of different febrile illnesses which makes it difficult to adhere to the clinical guidelines. The development of rigorous guidelines based on high quality research and a consensus from the core group of content experts are needed. An innovative financing mechanism for universal access to such appropriate management should also be considered.
  6. Singh S, Khang TF, Andiappan H, Nissapatorn V, Subrayan V
    Trans. R. Soc. Trop. Med. Hyg., 2012 May;106(5):322-6.
    PMID: 22480791 DOI: 10.1016/j.trstmh.2012.01.009
    Toxoplasma gondii is a public health risk in developing countries, especially those located in the tropics. Widespread infection may inflict a substantial burden on state resources, as patients can develop severe neurological defects and ocular diseases that result in lifelong loss of economic independence. We tested sera for IgG antibody from 493 eye patients in Malaysia. Overall age-adjusted seroprevalence was estimated to be 25% (95% CI: [21%, 29%]). We found approximately equal age-adjusted seroprevalence in Chinese (31%; 95% CI: [25%, 38%]) and Malays (29%; 95% CI: [21%, 36%]), followed by Indians (19%; 95% CI: [13%, 25%]). A logistic regression of the odds for T. gondii seroprevalence against age, gender, ethnicity and the occurrence of six types of ocular diseases showed that only age and ethnicity were significant predictors. The odds for T. gondii seroprevalence were 2.7 (95% CI for OR: [1.9, 4.0]) times higher for a patient twice as old as the other, with ethnicity held constant. In Malays, we estimated the odds for T. gondii seroprevalence to be 2.9 (95% CI for OR: [1.8, 4.5]) times higher compared to non-Malays, with age held constant. Previous studies of T. gondii seroprevalence in Malaysia did not explicitly adjust for age, rendering comparisons difficult. Our study highlights the need to adopt a more rigorous epidemiological approach in monitoring T. gondii seroprevalence in Malaysia.
  7. Roesnita B, Tay ST, Puthucheary SD, Sam IC
    Trans. R. Soc. Trop. Med. Hyg., 2012 Feb;106(2):131-3.
    PMID: 22112687 DOI: 10.1016/j.trstmh.2011.10.007
    Routine use of selective media improves diagnosis of Burkholderia pseudomallei, but resources may be limited in endemic developing countries. To maximise yield in the relatively low-prevalence setting of Kuala Lumpur, Malaysia, B. pseudomallei selective agar and broth were compared with routine media for 154 respiratory specimens from patients with community-acquired disease. Selective media detected three additional culture-positive specimens and one additional melioidosis patient, at a consumables cost of US$75. Burkholderia pseudomallei was not isolated from 74 diabetic foot ulcer samples. Following careful local evaluation, focused use of selective media may be cost-effective.
  8. Chandramathi S, Suresh K, Anita ZB, Kuppusamy UR
    Trans. R. Soc. Trop. Med. Hyg., 2012 Apr;106(4):267-9.
    PMID: 22340948 DOI: 10.1016/j.trstmh.2011.12.008
    Chemotherapy can cause immunosuppression, which may trigger latent intestinal parasitic infections in stools to emerge. This study investigated whether intestinal parasites can emerge as opportunistic infections in breast and colorectal cancer patients (n=46 and n=15, respectively) undergoing chemotherapy treatment. Breast cancer patients were receiving a 5-fluorouracil/epirubicin/cyclophosphamide (FEC) regimen (6 chemotherapy cycles), and colorectal cancer patients were receiving either an oxaliplatin/5-fluorouracil/folinic acid (FOLFOX) regimen (12 cycles) or a 5-fluorouracil/folinic acid (Mayo) regimen (6 cycles). Patients had Blastocystis hominis and microsporidia infections that were only present during the intermediate chemotherapy cycles. Thus, cancer patients undergoing chemotherapy should be screened repeatedly for intestinal parasites, namely B. hominis and microsporidia, as they may reduce the efficacy of chemotherapy treatments.
  9. Lono A, Kumar S, Chye TT
    Trans. R. Soc. Trop. Med. Hyg., 2011 Jul;105(7):409-13.
    PMID: 21596411 DOI: 10.1016/j.trstmh.2011.03.006
    The HIV-positive population, due to their immuno-compromised nature, is considered more susceptible to parasitic infections than other populations. However despite the reports of other opportunistic pathogens such as Cryptosporidium and tuberculosis reported in vulnerable communities, microsporidia have not been highlighted in the local HIV-positive population in Malaysia. This study aimed to provide preliminary information on the prevalence of microsporidia in the local HIV-population. Microsporidia were detected in 21/247 (8.5%) stool samples from the HIV-infected individuals, a significantly higher (P-value <0.05) prevalence than in the control group, in which 5/173 (2.9%) were positive. HIV patients were 3x more at risk for acquiring microspordium (OR: 3.12; 95% CI 1.15-8.44). Spores were ellipsoid in shape with outlines that stained dark pink with the interior a lighter shade. Approximately 21% of the positive specimens were from individuals in the 40-49 years age group. Ten individuals who were positive for microsporidia were also positive for other enteric parasites such as Blastocystis hominis and Giardia lamblia. We detected Encephalitozoon intestinalis DNA following nested PCR from three of 10 samples analysed, as demonstrated by an amplicon of 370bp. From the findings reported, it appears that microsporidial infection in humans may actually be more common than reported. We strongly advocate greater emphasis on personal hygiene through public education on personal hygiene and the consumption of boiled or filtered water.
  10. Yap FB
    Trans. R. Soc. Trop. Med. Hyg., 2011 Jul;105(7):405-8.
    PMID: 21600621 DOI: 10.1016/j.trstmh.2011.04.002
    A retrospective study was undertaken to determine the clinical features of cutaneous larva migrans (CLM) seen in the Department of Dermatology, Hospital Kuala Lumpur (Kuala Lumpur, Malaysia) and to assess the rate of correct diagnosis made by the referring primary care doctors. Clinical records of all 31 patients with CLM seen between January 2006 and June 2010 were retrieved. The majority of patients were male. The mean age was 32.2 years. Pruritus was reported in 83.9% of cases and serpiginous tracts in 100%. The mean lesion count was 4.4 and the mean duration of disease before presentation was 3.1 weeks. The majority of skin lesions were on the buttock and lower extremities. Only 45.2% of patients had the correct diagnosis made by the referring primary care doctors. Older age of patients and lower number of lesions were associated with a higher rate of correct diagnosis. The low rate of correct diagnosis made by the referring primary care doctors to the dermatologists in this study warrants the need for education of not only primary care doctors but also future primary care providers, consisting of medical students, house officers and junior medical officers.

    Study site: Department of Dermatology, Hospital Kuala Lumpur
  11. Naing C, Aung K, Win DK, Wah MJ
    Trans. R. Soc. Trop. Med. Hyg., 2010 Nov;104(11):695-705.
    PMID: 20850161 DOI: 10.1016/j.trstmh.2010.08.009
    Chloroquine (CQ) is a relatively inexpensive drug for treatment of malaria. If efficacy of CQ is still assumed, then it should be indicated in malaria treatment policies as the drug of choice for uncomplicated Plasmodium vivax malaria in endemic countries with resource constraints. The objective of this review is to summarize the existing evidence on the relative efficacy and safety of CQ in treating patients with uncomplicated P. vivax malaria in endemic countries. We searched online data bases (PUBMED, MEDLINE, EMBASE, The Cochrane Library) and the reference lists of the retrieved articles. Fifteen randomized controlled trials (n=6215) assessing the relative efficacy and safety of CQ for treatment of uncomplicated P. vivax malaria were included. CQ monotherapy was compared to CQ plus primaquine (PQ), artemisinin/artemether, artemisinin based combination therapy, quinine, CQ plus tafenoquine, chlorguanil plus dapsone, azithromycin, or placebo. Treatment efficacy was not significantly different between the CQ monotherapy group and that of the CQ with PQ 14 day group at 28 day follow-up (55/711, 7.7% vs 35/712, 4.9%; P=0.16). Evidence from the trials identified for this review draw a fairly clear conclusion about the relative efficacy and safety of CQ for treating uncomplicated P. vivax malaria infection. However, further research in this field with well powered, randomized, non-inferiority design, using the standardized protocol is needed.
  12. Othman S, Rahman NA, Yusof R
    Trans. R. Soc. Trop. Med. Hyg., 2010 Dec;104(12):806-8.
    PMID: 20800252 DOI: 10.1016/j.trstmh.2010.07.004
    In contrast to many viruses that escape the host's immune responses by suppressing the major histocompatibility complex (MHC) class I pathway, flaviviruses have been shown to up-regulate the cell surface expression of MHC class I complex. The mechanism by which dengue virus (DV) achieves this up-regulation remains unclear. Our investigation on the HLA-A2 gene in human liver cells demonstrated that all four serotypes of dengue virus, DV1 to DV4, resulted in variable degrees of promoter induction. This illustrates the importance of MHC class I transcription regulation in primary infections by different DV serotypes that may have even greater impact in secondary infections, associated with increased disease severity.
  13. Naing CM, Win DK
    Trans. R. Soc. Trop. Med. Hyg., 2010 May;104(5):311-2.
    PMID: 20206954 DOI: 10.1016/j.trstmh.2010.02.001
    Permanent neurological impairment or death arising from hospital-acquired hyponatremia in both children and adults is well documented. The choice of intravenous fluids for fluid resuscitation in critically ill patients is a top priority in evidence-based medicine. The question of whether colloids in comparison to crystalloids can improve mortality in such cases remains to be answered. Well powered, randomized clinical trials addressing the comparative efficacy of different types of intravenous fluids is a high priority as is the ethical justification for such trials. The understanding of the pathophysiological process serves important information on clinical practice.
  14. Sasidharan S, Uyub AM
    Trans. R. Soc. Trop. Med. Hyg., 2009 Apr;103(4):395-8.
    PMID: 19211121 DOI: 10.1016/j.trstmh.2008.11.021
    Helicobacter pylori infection is recognized as being strongly associated with chronic gastritis, duodenal ulceration and, probably, gastric carcinoma. Seroepidemiological studies have shown that a large proportion of healthy people have antibodies against H. pylori. A serological study was conducted in asymptomatic healthy blood donors in Northern Peninsular Malaysia to assess the seropositivity for H. pylori and to investigate the relationship with ethnic group, gender, ABO blood group and age. A total of 5370 serum samples collected from 3677 male and 1693 female donors in different age groups, and who had no gastrointestinal complaints, were studied with an in-house ELISA for the presence of H. pylori IgG and IgA antibodies. Seven hundred and sixty subjects (14.2%) were seropositive. The overall seropositivity did not differ with ethnicity, gender, ABO blood group and age among asymptomatic healthy blood donors in Northern Peninsular Malaysia.
  15. Yap FB
    Trans. R. Soc. Trop. Med. Hyg., 2010 Feb;104(2):168-9.
    PMID: 19766279 DOI: 10.1016/j.trstmh.2009.05.016
    A retrospective study was conducted to determine the clinical characteristics and treatment outcomes of 11 new patients with a histological diagnosis of chromoblastomycosis at Sarawak General Hospital, Malaysia, between 1996 and 2008. The majority (81.8%) were males, and the median age at presentation was 40 years. Over half the patients were farmers. All the patients had irregular verrucous lesions, mostly on the lower limbs (90.9%), and had initially been misdiagnosed. The mean duration of the lesions was 13.8 years. Oral terbinafine and itraconazole were administered to all the patients; clinical cure was seen in 54.5%, and partial response in 18.2%. Concomitant electrocautery and cryotherapy were only effective for small lesions.
  16. Lono A, Kumar GS, Chye TT
    Trans. R. Soc. Trop. Med. Hyg., 2010 Mar;104(3):214-8.
    PMID: 19716577 DOI: 10.1016/j.trstmh.2009.07.006
    Microsporidia are ubiquitous parasites thought to be closely related to fungi. Their presence in the environment means that humans are frequently exposed to infection. Stool samples were collected from 151 indigenous villagers from the eastern state of Pahang in 2005. The samples were concentrated with water-ether sedimentation, stained with modified trichrome stain and examined under oil-immersion microscopy. Thirty-two specimens (21.2%) were positive for microsporidia. Microsporidia were observed as ovoid or rounded ovoid shapes measuring approximately 1mum, with a bright pink outline containing a central or posterior vacuole. PCR amplification with specific primers on microscopy-positive specimens amplified Encephalitozoon intestinalis DNA from five of the ten specimens used.
  17. Hamat RA, Rahman AA, Osman M, Unyah NZ, Abdullah WO, Isa NH
    Trans. R. Soc. Trop. Med. Hyg., 2010 Feb;104(2):170-2.
    PMID: 19732927 DOI: 10.1016/j.trstmh.2009.07.019
    Cutaneous larva migrans is a common parasitic skin disease that can be easily prevented by wearing 'protective' footwear. However, this has been under-emphasized in terms of what constitutes the protective footwear. Even though the disease resolves spontaneously, the significant duration of the disease along with severity of pruritus make treatment unavoidable. Here, we present a very long-standing creeping eruption, which puzzled many attending clinicians handling the case, and the possibility of long socks as a causal effect on the development of cutaneous larva migrans infection.
  18. Thayan R, Huat TL, See LL, Tan CP, Khairullah NS, Yusof R, et al.
    Trans. R. Soc. Trop. Med. Hyg., 2009 Apr;103(4):413-9.
    PMID: 19203772 DOI: 10.1016/j.trstmh.2008.12.018
    Dengue infection is a major public health problem affecting millions of people living in tropical countries. With no suitable vaccines and specific antiviral drugs, treatment for dengue is usually symptomatic and supportive. Early diagnosis and recognition of severe disease is therefore crucial for better management of the patient. Two-dimension electrophoresis was used to identify disease-associated proteins that can be used for diagnosis and as drug targets for treatment. Two markers, identified by mass spectrometry analysis as alpha1-antitrypsin and NS1 proteins were found to be upregulated in dengue fever (DF; n=10) and dengue haemorrhagic fever (DHF; n=10) patients compared with healthy individuals (n=8). Both alpha1-antitrypsin and NS1 proteins were overexpressed two-fold in DHF patients compared with DF patients. Our study suggests that alpha1-antitrypsin and NS1 protein could be used as biomarkers as early indicators of DHF risk among patients with suspected dengue infection.
  19. Norhayati M, Azlin M, Al-Mekhlafi MH, Anisah N, Nor Aini U, Fatmah MS, et al.
    Trans. R. Soc. Trop. Med. Hyg., 2008 Dec;102(12):1274-8.
    PMID: 18602128 DOI: 10.1016/j.trstmh.2008.05.019
    An observational study was carried out to establish the existence of intestinal microsporidiosis among patients with and without gastrointestinal symptoms in Hospital Universiti Kebangsaan Malaysia, Malaysia. A total of 893 faecal specimens from hospitalized patients were examined for microsporidia using a modification of the usual Gram-chromotrope stain technique. One hundred and sixteen (13.0%) patients were positive for microsporidia: 84 (72.4%), 27 (23.3%) and 5 (4.3%) were low, moderate and high excreters of microsporidia spores, respectively. Of the 91 patients with available medical records, microsporidiosis was commonly observed in children aged 0-6 years (26.4%) and adults aged >or=31 years (57.2%). About one-third of this infection was observed in immunocompetent individuals. Among the immunosuppressive group, microsporidia were observed to be more prevalent in patients with haematological malignancy or a combination of malignancy and diabetes mellitus. About 74% of the patients who had microsporidia in their faeces had gastrointestinal symptoms, which could be related to infections or induced by immunosuppressive therapy. The role of microsporidia in causing gastrointestinal symptoms in this population is as yet unclear.
  20. Mohammed Mahdy AK, Lim YA, Surin J, Wan KL, Al-Mekhlafi MS
    Trans. R. Soc. Trop. Med. Hyg., 2008 May;102(5):465-70.
    PMID: 18377940 DOI: 10.1016/j.trstmh.2008.02.004
    This study was conducted to reassess the risk factors for giardiasis in communities of the Orang Asli (indigenous people) in Pahang, Malaysia. Stool samples were collected from 321 individuals (2-76 years old; 160 males, 161 females). Data were collected via laboratory analysis of faecal samples and a pre-tested standard questionnaire. River water samples were tested for Giardia cysts and Cryptosporidium oocysts. The overall prevalence of G. intestinalis infection was 23.7%. Children < or =12 years old had the highest infection rate and have been identified as a high risk group (odds ratio (OR)=6.2, 95% CI 1.5-27.0, P<0.005). The risk of getting giardiasis also appeared to be significantly associated with drinking piped water (OR=5.1, 95% CI 0.06-0.7, P<0.005) and eating raw vegetables (OR=2.4, 95% CI 0.2-0.6, P<0.005). In conclusion, sociodemographic factors have always been associated with the high prevalence of Giardia infections in Malaysia. However, the present study also highlights the need to look into the possibility of other risks such as water and food transmission routes. In future, it is necessary that these two aspects be considered in control strategies.
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