Displaying publications 1 - 20 of 150 in total

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  1. Vythilingam I, Lim YA, Venugopalan B, Ngui R, Leong CS, Wong ML, et al.
    Parasit Vectors, 2014;7:436.
    PMID: 25223878 DOI: 10.1186/1756-3305-7-436
    While transmission of the human Plasmodium species has declined, a significant increase in Plasmodium knowlesi/Plasmodium malariae cases was reported in Hulu Selangor, Selangor, Malaysia. Thus, a study was undertaken to determine the epidemiology and the vectors involved in the transmission of knowlesi malaria.
  2. Ngui R, Lee SC, Yap NJ, Tan TK, Aidil RM, Chua KH, et al.
    Acta Parasitol, 2014 Oct;59(4):737-44.
    PMID: 25236287 DOI: 10.2478/s11686-014-0306-3
    To estimate the current prevalence of gastrointestinal (GI) parasites in dogs and cats, a total of 105 fresh faecal samples were collected from rural areas in Peninsular Malaysia. Each faecal sample was examined for the presence of GI parasites by microscopic examination after formalin-ether concentration technique and for protozoa, trichrome and Ziehl-Neelsen staining were employed. The overall prevalence of GI parasitic infection was 88.6% (95% CI = 82.5-94.7) in which 88.3% of dogs and 89.3% of cats were infected with at least one parasites species, respectively. There were 14 different GI parasites species (nematodes, cestodes and protozoa) detected, including Ancylostoma spp. (62.9%), Toxocara spp. (32.4%), Trichuris vulpis (21.0%), Spirometra spp. (9.5%), Toxascaris leonina (5.7%), Dipylidium caninum (4.8%), Ascaris spp. (2.9%), Hymenolepis diminuta (1.0%) and others. General prevalence of GI parasites showed a significant difference between helminth (84.4%) and protozoa (34.3%) infections. Monoparasitism (38.1%) was less frequent than polyparasitism (46.7%). As several of these GI parasites are recognized as zoonotic agents, the results of this investigation revealed that local populations may be exposed to a broad spectrum of zoonotic agents by means of environmental contamination with dogs and cats faeces and this information should be used to mitigate public health risks. Prevention and control measures have to be taken in order to reduce the prevalence rates especially in socioeconomically disadvantaged communities where animals live in close proximity to people, poor levels of hygiene and overcrowding together with a lack in veterinary attention and zoonotic awareness.
  3. Al-Delaimy AK, Al-Mekhlafi HM, Nasr NA, Sady H, Atroosh WM, Nashiry M, et al.
    PLoS Negl Trop Dis, 2014 Aug;8(8):e3074.
    PMID: 25144662 DOI: 10.1371/journal.pntd.0003074
    This cross-sectional study aimed to investigate the current prevalence and risk factors associated with intestinal polyparasitism (the concurrent infection with multiple intestinal parasite species) among Orang Asli school children in the Lipis district of Pahang state, Malaysia.
  4. Lau YL, Fong MY, Mahmud R, Chang PY, Palaeya V, Cheong FW, et al.
    Malar J, 2011;10:197.
    PMID: 21774805 DOI: 10.1186/1475-2875-10-197
    The emergence of Plasmodium knowlesi in humans, which is in many cases misdiagnosed by microscopy as Plasmodium malariae due to the morphological similarity has contributed to the needs of detection and differentiation of malaria parasites. At present, nested PCR targeted on Plasmodium ssrRNA genes has been described as the most sensitive and specific method for Plasmodium detection. However, this method is costly and requires trained personnel for its implementation. Loop-mediated isothermal amplification (LAMP), a novel nucleic acid amplification method was developed for the clinical detection of P. knowlesi. The sensitivity and specificity of LAMP was evaluated in comparison to the results obtained via microscopic examination and nested PCR.
  5. Al-Mekhlafi HM, Nasr NA, Lim YAL, Elyana FN, Sady H, Atroosh WM, et al.
    Parasitology, 2019 10;146(12):1602-1614.
    PMID: 31303180 DOI: 10.1017/S0031182019000945
    This cross-sectional study aimed to determine the prevalence and risk factors of S. stercoralis infection among 1142 Orang Asli primary schoolchildren in six different states of Peninsular Malaysia. Fecal samples were examined using direct smear, formalin-ether sedimentation (FES), agar plate culture (APC) and PCR techniques. Overall, 15.8% of the children were found to be infected with S. stercoralis. The prevalence was 0.2, 1.3, 15.2 and 13.7% by direct smear, FES, APC and PCR, respectively. Multivariate analysis showed that an age of >10 years, being male, belonging to a Proto-Malay tribe, belonging to the Senoi tribe, indiscriminate defecation, using an unimproved water source for drinking water and not wearing shoes when outside were the significant risk factors of infection among these children. In conclusion, we provide new evidence on the occurrence of S. stercoralis in Malaysia to show that there is a relatively high prevalence of infection among Orang Asli schoolchildren. Therefore, the use of specific methods for detecting S. stercoralis should be considered when screening these children for intestinal parasites. Moreover, prevention and control measures specific to S. stercoralis should be integrated into the intestinal parasitic infections control programme in Malaysia.
  6. Basir R, Hasballah K, Jabbarzare M, Gam LH, Abdul Majid AM, Yam MF, et al.
    Trop Biomed, 2012 Sep;29(3):405-21.
    PMID: 23018504 MyJurnal
    The involvement of interleukin-18 (IL-18) and the effects of modulating its release on the course of malaria infection were investigated using Plasmodium berghei ANKA infection in ICR mice as a model. Results demonstrated that plasma IL-18 concentrations in malarial mice were significantly elevated and positively correlated with the percentage parasitaemia development. Significant expressions of IL-18 were also observed in the brain, spleen and liver tissues. Slower development of parasitaemia was observed significantly upon inhibition and neutralization of IL-18, whereas faster development of parasitaemia was recorded when the circulating levels of IL-18 were further augmented during the infection. Inhibition and neutralization of IL-18 production also resulted in a significant decrease of plasma concentrations of pro-inflammatory cytokines (TNFα, IFNγ, IL-1α and IL-6), whereas the anti-inflammatory cytokine, IL-10, was significantly increased. Augmenting the release of IL- 18 during the infection on the other hand resulted in the opposite. Early mortality in malarial mice was also observed when the circulating levels of IL-18 were further augmented. Results proved the important role of IL-18 in immune response against malaria and suggest that IL-8 is pro-inflammatory in nature and may involve in mediating the severity of the infection through a pathway of elevating the pro-inflammatory cytokine and limiting the release of anti-inflammatory cytokine.
  7. Nasr NA, Al-Mekhlafi HM, Lim YAL, Elyana FN, Sady H, Atroosh WM, et al.
    Pathog Glob Health, 2020 05;114(3):145-159.
    PMID: 32249689 DOI: 10.1080/20477724.2020.1747855
    A cross-sectional survey was conducted among 1,142 Orang Ali schoolchildren in six states of Peninsular Malaysia to investigate the current prevalence and risk factors of STH infections. Faecal samples were examined using direct smear, formalin-ether sedimentation, Kato-Katz, and Harada-Mori methods. A pre-tested questionnaire was used to collect information on the demographic, socioeconomic, personal hygiene, and health status of the participants. Overall, 70.1% (95% CI = 67.4, 72.7) of the participants were infected with at least one of the STH species. The prevalence of Ascaris lumbricoides, Trichuris trichiura, and hookworm infections was 63.1%, 61.8% and 11.5%, respectively. Moderate-to-heavy STH infections accounted for 61.3% of the total infections. Univariate and logistic regression analyses revealed different sets of risk factors, with age (> 10 years) being the significant risk factor of all three STH species. Moreover, other species-specific risk factors were identified including being a member of the Senoi tribe, family size (≥ 7 members), school size (150-250 pupils), maternal unemployment, unimproved source of drinking water, lacking improved toilet in the house, inadequate WASH facilities at school, not washing hands before eating, and not washing fruits before eating; presence of domestic animals, and not wearing shoes when outside. The high prevalence of STH infections found in the study population exceeds the WHO policy intervention threshold (20% prevalence). Thus, an innovative holistic approach should be adopted to control STH infections among these children as part of the efforts to improve the quality of life of the entire Orang Asli population. .
  8. Yusof KM, Avery-Kiejda KA, Ahmad Suhaimi S, Ahmad Zamri N, Rusli MEF, Mahmud R, et al.
    Diagnostics (Basel), 2021 Jul 21;11(8).
    PMID: 34441238 DOI: 10.3390/diagnostics11081303
    Breast cancer has been reported to have the highest survival rate among various cancers. However, breast cancer survivors face several challenges following breast cancer treatment including breast cancer-related lymphedema (BCRL), sexual dysfunction, and psychological distress. This study aimed to investigate the potential risk factors of BCRL in long term breast cancer survivors. A total of 160 female breast cancer subjects were recruited on a voluntary basis and arm lymphedema was assessed through self-reporting of diagnosis, arm circumference measurement, and ultrasound examination. A total of 33/160 or 20.5% of the women developed BCRL with significantly higher scores for upper extremity disability (37.14 ± 18.90 vs. 20.08 ± 15.29, p < 0.001) and a lower score for quality of life (103.91 ± 21.80 vs. 115.49 ± 16.80, p = 0.009) as compared to non-lymphedema cases. Univariate analysis revealed that multiple surgeries (OR = 5.70, 95% CI: 1.21-26.8, p < 0.001), axillary lymph nodes excision (>10) (OR = 2.83, 95% CI: 0.94-8.11, p = 0.047), being overweight (≥25 kg/m2) (OR = 2.57, 95% CI: 1.04 - 6.38, p = 0.036), received fewer post-surgery rehabilitation treatment (OR = 2.37, 95% CI: 1.05-5.39, p = 0.036) and hypertension (OR = 2.38, 95% CI: 1.01-5.62, p = 0.043) were associated with an increased risk of BCRL. Meanwhile, multivariate analysis showed that multiple surgeries remained significant and elevated the likelihood of BCRL (OR = 5.83, 95% CI: 1.14-29.78, p = 0.034). Arm swelling was more prominent in the forearm area demonstrated by the highest difference of arm circumference measurement when compared to the upper arm (2.07 ± 2.48 vs. 1.34 ± 1.91 cm, p < 0.001). The total of skinfold thickness of the affected forearm was also significantly higher than the unaffected arms (p < 0.05) as evidenced by the ultrasound examination. The continuous search for risk factors in specific populations may facilitate the development of a standardized method to reduce the occurrence of BCRL and provide better management for breast cancer patients.
  9. Junaid QO, Khaw LT, Mahmud R, Ong KC, Lau YL, Borade PU, et al.
    Parasite, 2017;24:38.
    PMID: 29034874 DOI: 10.1051/parasite/2017040
    BACKGROUND: As the quest to eradicate malaria continues, there remains a need to gain further understanding of the disease, particularly with regard to pathogenesis. This is facilitated, apart from in vitro and clinical studies, mainly via in vivo mouse model studies. However, there are few studies that have used gerbils (Meriones unguiculatus) as animal models. Thus, this study is aimed at characterizing the effects of Plasmodium berghei ANKA (PbA) infection in gerbils, as well as the underlying pathogenesis.

    METHODS: Gerbils, 5-7 weeks old were infected by PbA via intraperitoneal injection of 1 × 106 (0.2 mL) infected red blood cells. Parasitemia, weight gain/loss, hemoglobin concentration, red blood cell count and body temperature changes in both control and infected groups were monitored over a duration of 13 days. RNA was extracted from the brain, spleen and whole blood to assess the immune response to PbA infection. Organs including the brain, spleen, heart, liver, kidneys and lungs were removed aseptically for histopathology.

    RESULTS: Gerbils were susceptible to PbA infection, showing significant decreases in the hemoglobin concentration, RBC counts, body weights and body temperature, over the course of the infection. There were no neurological signs observed. Both pro-inflammatory (IFNγ and TNF) and anti-inflammatory (IL-10) cytokines were significantly elevated. Splenomegaly and hepatomegaly were also observed. PbA parasitized RBCs were observed in the organs, using routine light microscopy and in situ hybridization.

    CONCLUSION: Gerbils may serve as a good model for severe malaria to further understand its pathogenesis.

  10. Ngui R, Ravindran S, Ong DB, Chow TK, Low KP, Nureena ZS, et al.
    J Clin Microbiol, 2014 Sep;52(9):3468-70.
    PMID: 24989613 DOI: 10.1128/JCM.01191-14
    We report a rare and unusual case of invasive Enterobius vermicularis infection in a fallopian tube. The patient was a 23-year-old Malaysian woman who presented with suprapubic pain and vaginal bleeding. A clinical diagnosis of ruptured right ovarian ectopic pregnancy was made. She underwent a laparotomy with a right salpingo-oophorectomy. Histopathological examination of the right fallopian tube showed eggs and adult remnants of E. vermicularis, and the results were confirmed using PCR and DNA sequencing.
  11. Al-Mekhlafi HM, Al-Maktari MT, Jani R, Ahmed A, Anuar TS, Moktar N, et al.
    PLoS Negl Trop Dis, 2013;7(10):e2516.
    PMID: 24205426 DOI: 10.1371/journal.pntd.0002516
    Giardia duodenalis infection and malnutrition are still considered as public health problems in many developing countries especially among children in rural communities. This study was carried out among Aboriginal (Orang Asli) primary schoolchildren in rural peninsular Malaysia to investigate the burden and the effects of Giardia infection on growth (weight and height) of the children.
  12. Yusof R, Ahmed MA, Jelip J, Ngian HU, Mustakim S, Hussin HM, et al.
    Emerg Infect Dis, 2016 Aug;22(8):1371-80.
    PMID: 27433965 DOI: 10.3201/eid2208.151885
    Infections of humans with the zoonotic simian malaria parasite Plasmodium knowlesi occur throughout Southeast Asia, although most cases have occurred in Malaysia, where P. knowlesi is now the dominant malaria species. This apparently skewed distribution prompted an investigation of the phylogeography of this parasite in 2 geographically separated regions of Malaysia, Peninsular Malaysia and Malaysian Borneo. We investigated samples collected from humans and macaques in these regions. Haplotype network analyses of sequences from 2 P. knowlesi genes, type A small subunit ribosomal 18S RNA and cytochrome c oxidase subunit I, showed 2 genetically distinct divergent clusters, 1 from each of the 2 regions of Malaysia. We propose that these parasites represent 2 distinct P. knowlesi types that independently became zoonotic. These types would have evolved after the sea-level rise at the end of the last ice age, which separated Malaysian Borneo from Peninsular Malaysia.
  13. Amir A, Ngui R, Ismail WH, Wong KT, Ong JS, Lim YA, et al.
    Am J Trop Med Hyg, 2016 Aug 03;95(2):410-2.
    PMID: 27325803 DOI: 10.4269/ajtmh.16-0007
    Human anisakiasis is a zoonosis acquired by eating raw or undercooked infected seafood. Herein, we report a case of acute dysentery caused by anisakiasis in a 64-year-old man in Malaysia. A colonoscopy was performed and a nematode larva was found penetrating the mucosa of the ascending colon. Bleeding was observed at the site of penetration. Y-shaped lateral epidermal cords were seen from the cross section of the worm, which is a prominent feature of Anisakis larva. Molecular analysis using polymerase chain reaction of cytochrome oxidase 2 (cox2) gene confirmed the specimen to be larva of Anisakis simplex.
  14. Khan MB, Sonaimuthu P, Lau YL, Al-Mekhlafi HM, Mahmud R, Kavana N, et al.
    Parasit Vectors, 2014;7:505.
    PMID: 25388913 DOI: 10.1186/s13071-014-0505-7
    The neglected tropical diseases, echinococcosis, schistosomiasis and toxoplasmosis are all globally widespread zoonotic diseases with potentially harmful consequences. There is very limited data available on the prevalence of these infections, except for schistosmiasis, in underdeveloped countries. This study aimed to determine the seroprevalence of Echinococcus multilocularis, Schistosoma mansoni, and Toxoplasma gondii antibodies in populations from the Monduli and Babati districts in Tanzania.
  15. Al-Delaimy AK, Al-Mekhlafi HM, Lim YA, Nasr NA, Sady H, Atroosh WM, et al.
    Parasit Vectors, 2014;7:416.
    PMID: 25179100 DOI: 10.1186/1756-3305-7-416
    This study was carried out to develop a health education learning package (HELP) about soil-transmitted helminth (STH) infections, and to evaluate what impact such a package could have in terms of reducing the incidence and intensity of STH infections among Orang Asli schoolchildren in Pahang, Malaysia.
  16. Yusof R, Lau YL, Mahmud R, Fong MY, Jelip J, Ngian HU, et al.
    Malar J, 2014;13:168.
    PMID: 24886266 DOI: 10.1186/1475-2875-13-168
    Plasmodium knowlesi is a simian parasite that has been recognized as the fifth species causing human malaria. Naturally-acquired P. knowlesi infection is widespread among human populations in Southeast Asia. The aim of this epidemiological study was to determine the incidence and distribution of malaria parasites, with a particular focus on human P. knowlesi infection in Malaysia.
  17. Ngui R, Shafie A, Chua KH, Mistam MS, Al-Mekhlafi HM, Sulaiman WW, et al.
    Geospat Health, 2014 May;8(2):365-76.
    PMID: 24893014
    Soil-transmitted helminth (STH) infections in Malaysia are still highly prevalent, especially in rural and remote communities. Complete estimations of the total disease burden in the country has not been performed, since available data are not easily accessible in the public domain. The current study utilised geographical information system (GIS) to collate and map the distribution of STH infections from available empirical survey data in Peninsular Malaysia, highlighting areas where information is lacking. The assembled database, comprising surveys conducted between 1970 and 2012 in 99 different locations, represents one of the most comprehensive compilations of STH infections in the country. It was found that the geographical distribution of STH varies considerably with no clear pattern across the surveyed locations. Our attempt to generate predictive risk maps of STH infections on the basis of ecological limits such as climate and other environmental factors shows that the prevalence of Ascaris lumbricoides is low along the western coast and the southern part of the country, whilst the prevalence is high in the central plains and in the North. In the present study, we demonstrate that GIS can play an important role in providing data for the implementation of sustainable and effective STH control programmes to policy-makers and authorities in charge.
  18. Ibrahim RM, Hamdan NS, Mahmud R, Imam MU, Saini SM, Rashid SN, et al.
    J Transl Med, 2014;12:82.
    PMID: 24685020 DOI: 10.1186/1479-5876-12-82
    The risk of cardiovascular diseases (CVD) is increased tremendously among menopausal women, and there is an increasing demand for alternative therapies for managing factors like dyslipidemia that contribute to CVD development.
  19. Anthony CN, Lau YL, Sum JS, Fong MY, Ariffin H, Zaw WL, et al.
    Malar J, 2013;12:308.
    PMID: 24007496 DOI: 10.1186/1475-2875-12-308
    Malaria may be a serious complication of blood transfusion due to the asymptomatic persistence of parasites in some donors. This case report highlights the transfusion-transmitted malaria of Plasmodium vivax in a child diagnosed with germ cell tumour. This child had received blood transfusion from three donors and a week later started developing malaria like symptoms. Nested PCR and sequencing confirmed that one of the three donors was infected with P. vivax and this was transmitted to the 12-year-old child. To the best of the authors' knowledge, this is the first reported transfusion-transmitted malaria case in Malaysia.
  20. Lau YL, Lee WC, Tan LH, Kamarulzaman A, Syed Omar SF, Fong MY, et al.
    Malar J, 2013;12:389.
    PMID: 24180319 DOI: 10.1186/1475-2875-12-389
    Plasmodium ovale is one of the causative agents of human malaria. Plasmodium ovale infection has long been thought to be non-fatal. Due to its lower morbidity, P. ovale receives little attention in malaria research.
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