Displaying publications 61 - 80 of 141 in total

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  1. Fulltext Toxoplasmosis in HIV/AIDS patients in Malaysia
    Nissapatorn V, Lee CK, Cho SM, Rohela M, Anuar AK, Quek KF, et al.
    Southeast Asian J Trop Med Public Health, 2003;34 Suppl 2:80-5.
    PMID: 19238664
    Three hundred and one sera of HIV/AIDS patients were tested for anti-Toxoplasma IgG antibody by ELISA technique. The seroprevalence of toxoplasmosis was 41.2% (95% CI: 35.5-46.9) in HIV/AIDS patients. The seroprevalence was significantly higher in the Malay (57.9%) than the Chinese (38.7%), followed by the Indian patients (29.6%) (p<0.05). No possible risk factor, such as contact with cats, consumption of uncooked meat, and history of blood transfusions was found to have any significant association with the presence of anti-Toxoplasma antibody in the study sample (p>0.05). Multivariate analysis was employed to find any association between Toxoplasma seroprevalence and a single subject having single or multiple risk factors. It was found that the association was not statistically significant (p>0.05). Among the HIV/AIDS study samples, 124 (41.2%) samples were found to have positive anti-Toxoplasma antibody, the association between the presence of anti-Toxoplasma antibody and CD4 cell count was determined but no statistically significant association was found (p>0.05). During the study period, only one case of active CNS toxoplasmosis was registered and the diagnostic criteria included: clinical presentations, CT scan finding, serological evidence of anti-Toxoplasma IgG antibody, and respose to anti-Toxoplasma therapy.
    Matched MeSH terms: Toxoplasmosis/complications*; Toxoplasmosis/epidemiology*
  2. Fulltext Review on human toxoplasmosis in Malaysia: the past, present and prospective future
    Nissapatorn V, Abdullah KA
    Southeast Asian J Trop Med Public Health, 2004 Mar;35(1):24-30.
    PMID: 15272740
    We reviewed various studies regarding human toxoplasmosis in Malaysia. They showed a varying prevalence of specific Toxoplasma antibodies among the Malaysian population. The Malays have shown the highest seroprevalence of toxoplasmosis, by most studies, when compared to other races. Demographic profiles have shown that Toxoplasma seropositivity is higher in males than females, lower in people with higher incomes, higher in the unemployed and tends to increase with age. In general, the route of transmission, such as contact with a cat, consumption of undercooked meat and blood transfusion were shown to have no significant association with Toxoplasma seropositivity (p > 0.05). The immune status (CD4 cell count < 200 cell/mm3) was strongly associated with toxoplasmic encephalitis (p < 0.05).
    Matched MeSH terms: Toxoplasmosis/diagnosis*; Toxoplasmosis/epidemiology*
  3. Fulltext Identification, production and assessment of two Toxoplasma gondii recombinant proteins for use in a Toxoplasma IgG avidity assay
    Teh AY, Amerizadeh A, Osman S, Yunus MH, Noordin R
    Pathog Glob Health, 2016 Oct-Dec;110(7-8):277-286.
    PMID: 27697019
    The IgG avidity assay is an important tool in the management of suspected toxoplasmosis in pregnant women. This study aimed to produce new Toxoplasma gondii recombinant proteins and to assess their usefulness in an IgG avidity assay. Toxoplasma positive and negative serum samples were used, the former were categorized into low (LGA) and high (HGA) IgG avidity samples. Immunoblots were performed on 30 T. gondii cDNA clones to determine the reactivity and IgG avidity to the expressed proteins. Two of the clones were found to have diagnostic potential and were analyzed further; AG12b encoded T. gondii apical complex lysine methyltransferase (AKMT) protein and AG18 encoded T. gondii forkhead-associated (FHA) domain-containing protein. The His-tagged recombinant proteins, rAG12b and rAG18, were expressed and tested with LGA and HGA samples using an IgG avidity western blot and ELISA. With the IgG avidity western blot, rAG12b identified 86.4% of LGA and 90.9% of HGA samples, whereas rAG18 identified 81.8% of both LGA and HGA samples. With the IgG avidity ELISA, rAG12b identified 86.4% of both LGA and HGA samples, whereas rAG18 identified 77.3% of LGA and 86.4% of HGA serum samples. This study showed that the recombinant antigens were able to differentiate low avidity and high avidity serum samples, suggesting that they are potential candidates for use in the Toxoplasma IgG avidity assay.
    Matched MeSH terms: Toxoplasmosis/immunology*; Toxoplasmosis/parasitology
  4. Fulltext In vitro anti-Toxoplasma gondii activity of root extract/fractions of Eurycoma longifolia Jack
    Kavitha N, Noordin R, Chan KL, Sasidharan S
    BMC Complement Altern Med, 2012;12:91.
    PMID: 22781137 DOI: 10.1186/1472-6882-12-91
    Toxoplasma gondii infection causes toxoplasmosis, an infectious disease with worldwide prevalence. The limited efficiency of drugs against this infection, their side effects and the potential appearance of resistant strains make the search of novel drugs an essential need. We examined Eurycoma longifolia root extract and fractions as potential sources of new compounds with high activity and low toxicity. The main goal of this study was to investigate the anti-T. gondii activity of crude extract (TACME) and four fractions (TAF 273, TAF 355, TAF 191 and TAF 401) from E. longifolia, with clindamycin as the positive control.
    Matched MeSH terms: Toxoplasmosis/drug therapy; Toxoplasmosis/parasitology
  5. Fulltext Sero-diagnostic evaluation of Toxoplasma gondii recombinant Rhoptry antigen 8 expressed in E. coli
    Sonaimuthu P, Fong MY, Kalyanasundaram R, Mahmud R, Lau YL
    Parasit Vectors, 2014;7:297.
    PMID: 24986686 DOI: 10.1186/1756-3305-7-297
    Toxoplasma gondii infects all warm-blooded animals, including humans. Early diagnosis and determining the infective stage are critical for effectively treating immunosuppressed individuals and pregnant women with toxoplasmosis. Among the rhoptry proteins of the parasite, Rhoptry protein 8 (ROP8), is known to be expressed during the early stages of T. gondii infection and is involved in parasitophorous vacuole formation. In this study, we have investigated the diagnostic efficacy of recombinant ROP8 (rROP8).
    Matched MeSH terms: Toxoplasmosis/blood; Toxoplasmosis/diagnosis
  6. Fulltext Is it toxoplasma encephalitis, HIV encephalopathy or brain tuberculoma?
    Nimir AR, Osman E, Ibrahim IA, Saliem AM
    BMJ Case Rep, 2013;2013.
    PMID: 23580678 DOI: 10.1136/bcr-2013-008803
    A 31-year-old Malaysian man was presented with an episode of seizures by the roadside, after having been recently diagnosed as HIV positive accompanied with miliary tuberculosis. On physical examination, he was oriented to person, but not to time or place. There was no neck stiffness or papilloedema. The other systemic examination was unremarkable. Chest examination revealed crepitations at the upper zone of the right lung. After diagnosis suspicion, the case was confirmed as toxoplasma encephalitis by MRI and serological tests. Patient was treated with trimethoprim/sulfamethoxazole 480-2400 mg/day with folinic acid supplement for 60 days. Two months later, a repeat brain MRI showed resolution of the cerebral lesions.
    Matched MeSH terms: Toxoplasmosis, Cerebral/diagnosis*; Toxoplasmosis, Cerebral/drug therapy*
  7. Evaluation of Toxoplasma gondii-recombinant dense granular protein (GRA2) for serodiagnosis by western blot
    Ching XT, Lau YL, Fong MY, Nissapatorn V
    Parasitol Res, 2013 Mar;112(3):1229-36.
    PMID: 23274488 DOI: 10.1007/s00436-012-3255-5
    Toxoplasma gondii infects all warm-blooded animals including humans, causing serious public health problems and great economic loss in the food industry. Commonly used serological tests involve preparation of whole Toxoplasma lysate antigens from tachyzoites which are costly and hazardous. An alternative method for better antigen production involving the prokaryotic expression system was therefore used in this study. Recombinant dense granular protein, GRA2, was successfully cloned, expressed, and purified in Escherichia coli, BL21 (DE3) pLysS. The potential of this purified antigen for diagnosis of human infections was evaluated through western blot analysis against 100 human serum samples. Results showed that the rGRA2 protein has 100 and 61.5 % sensitivity towards acute and chronic infection, respectively, in T. gondii-infected humans, indicating that this protein is useful in differentiating present and past infections. Therefore, it is suitable to be used as a sensitive and specific molecular marker for the serodiagnosis of Toxoplasma infection in both humans and animals.
    Matched MeSH terms: Toxoplasmosis/diagnosis*; Toxoplasmosis/immunology
  8. Fulltext Unusual manifestation of cutaneous toxoplasmosis in a HIV-positive patient
    Fong MY, Wong KT, Rohela M, Tan LH, Adeeba K, Lee YY, et al.
    Trop Biomed, 2010 Dec;27(3):447-50.
    PMID: 21399585 MyJurnal
    We report a case of unusual cutaneous toxoplasmosis manifestation in a HIV-positive patient. He presented with hard and painful nodular lesions on the arms, hands and chest. Serology tests for anti-Toxoplasma antibody were negative. However, histopathologic examination of the lesion revealed foci of macrophages containing crescent-shaped organisms resembling the zoites of the protozoan parasite Toxoplasma gondii. Ultrastructure examination under electron microscopy and PCR confirmed the organism as T. gondii.
    Matched MeSH terms: Toxoplasmosis/diagnosis*; Toxoplasmosis/pathology*
  9. Fulltext IgG avidity assay: a tool for excluding acute toxoplasmosis in prolonged IgM titer sera from pregnant women
    Emelia O, Rahana AR, Mohamad Firdaus A, Cheng HS, Nursyairah MS, Fatinah AS, et al.
    Trop Biomed, 2014 Dec;31(4):633-40.
    PMID: 25776588 MyJurnal
    An accurate diagnosis for toxoplasmosis is crucial for pregnant women as this infection may lead to severe sequelae in the fetus. The value of IgG avidity assay as a tool to determine acute and chronic toxoplasmosis during pregnancy was evaluated in Universiti Kebangsaan Malaysia Medical Centre (UKMMC). In this study, 281 serum samples from 281 pregnant women in various trimesters were collected. These samples were assayed using specific anti-Toxoplasma IgM and IgG antibodies, followed by IgG avidity test. The overall seroprevalence of toxoplasmosis in pregnant women was 35.2% (33.5% for anti-Toxoplasma IgG and 1.8% for both anti-Toxoplasma IgG and IgM antibodies). Of 5 (1.8%) serum samples positive for IgM ELISA, 4 had high-avidity antibodies, suggesting past infection and one sample with borderline avidity index. Two samples with low avidity were from IgM negative serum samples. The IgG avidity assay exhibited an excellent specificity of 97.6% and a negative predictive value (NPV) of 95.6%. The study also demonstrated no significant correlation between avidity indexes of the sera with IgG (r=0.12, p=0.24) and IgM (r=-0.00, p=0.98), suggesting the complementary needs of the two tests for a better diagnosis outcome. These findings highlight the usefulness of IgG avidity assay in excluding a recently acquired toxoplasmosis infection in IgM-positive serum sample.
    Matched MeSH terms: Toxoplasmosis/diagnosis*; Toxoplasmosis/epidemiology
  10. Fulltext Performance of 2 Polymerization Protocols Targeting Cloned Toxoplasma Parasites
    Hanafy NA, Badr MS, Nasr GM
    Open Access Maced J Med Sci, 2018 Sep 25;6(9):1577-1580.
    PMID: 30337968 DOI: 10.3889/oamjms.2018.400
    BACKGROUND: Toxoplasma gondii is a common parasitic infection of humans. Infection is usually mild. Serious complications can occur in pregnant and immunocompromised patients.

    AIM: The present study aims to investigate the performance of 2 different PCR protocols; real-time quantitative molecular assays (qPCR) and conventional molecular assays (cPCR), using 2 different sets of primers and by using cloned purified Toxoplasma genomic substances to be evaluated as reference samples.

    METHODS: The target DNA was provided in 8 different quantities.

    RESULTS: Amplification failure was reported only with the cPCR in samples of low concentrations using both primer sets. Quantitative PCR detected the 8 different dilutions of the purified Toxoplasma gondii using the 2 sets of primers while cPCR was sensitive to detect only 6 different dilutions.

    CONCLUSION: Generally real-time quantitative molecular assays, is easy to use method compared to conventional PCR assay and produces more reliable results within only one hour time but still the possible application of qPCRs in routine diagnosis necessitates analysis of a large number of clinical samples in further studies to make the proper choice.

    Matched MeSH terms: Toxoplasmosis
  11. Isolation and genotyping of Toxoplasma gondii from free-range ducks in Malaysia
    Puvanesuaran VR, Noordin R, Balakrishnan V
    Avian Dis, 2013 Mar;57(1):128-32.
    PMID: 23678741
    Toxoplasma gondii is a parasitic protozoan that infects nearly one-third of humans. The present study was performed to isolate and genotype T. gondii from free-range ducks in Malaysia. Sera, heads, and hearts from 205 ducks were obtained from four states in Peninsular Malaysia, and 30 (14.63%) sera were found to be seropositive when assayed with the modified agglutination test (MAT > or = 1:6). All the positive samples were inoculated into mice, and T. gondii was successfully isolated from four individual duck samples (1.95%), which were initially found to be strongly seropositive (MAT > or = 1:24). The isolates were subjected to PCR-RFLP analysis, and two T. gondii strains were identified: type I and type II. This is the first reported study on the genetic characterization of T. gondii isolates from free-range farm animals in Southeast Asia.
    Matched MeSH terms: Toxoplasmosis, Animal/blood; Toxoplasmosis, Animal/epidemiology*; Toxoplasmosis, Animal/parasitology
  12. Fulltext Seroepidemiology of toxoplasmosis in renal patients
    Nissapatorn V, Leong TH, Lee R, Init-Ithoi, Ibrahim J, Yen TS
    Southeast Asian J Trop Med Public Health, 2011 Mar;42(2):237-47.
    PMID: 21710842
    Toxoplasmosis is an important parasitic disease in immunosuppressed patients. This prospective study was conducted to determine the seroprevalence, associated risk factors and the incidence of clinically confirmed toxoplasmosis among renal patients at the University of Malaya Medical Center, Kuala Lumpur, Malaysia. We interviewed 247 renal patients, each of whom answered an epidemiological questionnaire, and collected blood samples for measurement of anti-Toxoplasma IgG and IgM antibodies by ELISA. Overall seroprevalence of latent toxoplasmosis was observed in 126 (51%) renal patients. Race (Malays), marital status (married) and primary level of education, were all factors associated with a greater chance of Toxoplasma infection. A case of clinically confirned toxoplasmosis was diagnosed in a renal transplant recipient as a result of immunosuppression. Based on the findings obtained, this preliminary study shows a high prevalence of latent toxoplasmosis in renal patients. Risk factors may have significantly contributed to Toxoplasma acquisition in these patients. We recommend further studies be carried out to monitor for trends in toxoplasmosis among immunosuppressed patients.
    Matched MeSH terms: Toxoplasmosis/complications*; Toxoplasmosis/epidemiology*; Toxoplasmosis/parasitology
  13. Fulltext Seropositivity and serointensity of Toxoplasma gondii antibodies and DNA among patients with schizophrenia
    Omar A, Bakar OC, Adam NF, Osman H, Osman A, Suleiman AH, et al.
    Korean J Parasitol, 2015 Feb;53(1):29-34.
    PMID: 25748706 DOI: 10.3347/kjp.2015.53.1.29
    The aim of this cross sectional case control study was to examine the serofrequency and serointensity of Toxoplasma gondii (Tg) IgG, IgM, and DNA among patients with schizophrenia. A total of 101 patients with schizophrenia and 55 healthy controls from Sungai Buloh Hospital, Selangor, Malaysia and University Malaya Medical Center (UMMC) were included in this study. The diagnosis of schizophrenia was made based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). The presence of Tg infection was examined using both indirect (ELISA) and direct (quantitative real-time PCR) detection methods by measuring Tg IgG and IgM and DNA, respectively. The serofrequency of Tg IgG antibodies (51.5%, 52/101) and DNA (32.67%, 33/101) among patients with schizophrenia was significantly higher than IgG (18.2%, 10/55) and DNA (3.64%, 2/55) of the controls (IgG, P=0.000, OD=4.8, CI=2.2-10.5; DNA, P=0.000, OD=12.9, CI=2.17-10.51). However, the Tg IgM antibody between patients with schizophrenia and controls was not significant (P>0.005). There was no significant difference (P>0.005) in both serointensity of Tg IgG and DNA between patients with schizophrenia and controls. These findings have further demonstrated the strong association between the active Tg infection and schizophrenia.
    Matched MeSH terms: Toxoplasmosis/immunology; Toxoplasmosis/epidemiology*; Toxoplasmosis/parasitology*
  14. Vaccination challenges and strategies against long-lived Toxoplasma gondii
    Loh FK, Nathan S, Chow SC, Fang CM
    Vaccine, 2019 07 09;37(30):3989-4000.
    PMID: 31186188 DOI: 10.1016/j.vaccine.2019.05.083
    Since the discovery of Toxoplasma gondii in 1908, it is estimated that one-third of the global population has been exposed to this ubiquitous intracellular protozoan. The complex life cycle of T. gondii has enabled itself to overcome stress and transmit easily within a broad host range thus achieving a high seroprevalence worldwide. To date, toxoplasmosis remains one of the most prevalent HIV-associated opportunistic central nervous system infections. This review presents a comprehensive overview of different vaccination approaches ranging from traditional inactivated whole-T. gondii vaccines to the popular DNA vaccines. Extensive discussions are made to highlight the challenges in constructing these vaccines, selecting adjuvants as well as delivery methods, immunisation approaches and developing study models. Herein we also deliberate over the latest and promising enhancement strategies that can address the limitations in developing an effective T. gondii prophylactic vaccine.
    Matched MeSH terms: Toxoplasmosis/prevention & control
  15. Fulltext Identification of potential dual -targets anti- toxoplasma gondii compounds through structure-based virtual screening and in-vitro studies
    Salin NH, Noordin R, Al-Najjar BO, Kamarulzaman EE, Yunus MH, Karim IZA, et al.
    PLoS One, 2020;15(5):e0225232.
    PMID: 32442170 DOI: 10.1371/journal.pone.0225232
    Toxoplasma gondii is the etiologic agent of toxoplasmosis, a disease which can lead to morbidity and mortality of the fetus and immunocompromised individuals. Due to the limited effectiveness or side effects of existing drugs, the search for better drug candidates is still ongoing. In this study, we performed structure-based screening of potential dual-targets inhibitors of active sites of T. gondii drug targets such as uracil phosphoribosyltransferase (UPRTase) and adenosine kinase (AK). First screening of virtual compounds from the National Cancer Institute (NCI) was performed via molecular docking. Subsequently, the hit compounds were tested in-vitro for anti- T. gondii effect using cell viability assay with Vero cells as host to determine cytotoxicity effects and drug selectivities. Clindamycin, as positive control, showed a selectivity index (SI) of 10.9, thus compounds with SI > 10.9 specifically target T. gondii proliferation with no significant effect on the host cells. Good anti- T. gondii effects were observed with NSC77468 (7-ethoxy-4-methyl-6,7-dihydro-5H-thiopyrano[2,3-d]pyrimidin-2-amine) which showed SI values of 25. This study showed that in-silico selection can serve as an effective way to discover potentially potent and selective compounds against T. gondii.
    Matched MeSH terms: Toxoplasmosis/drug therapy*
  16. Fulltext Deciphering the Draft Genome of Toxoplasma gondii RH Strain
    Lau YL, Lee WC, Gudimella R, Zhang G, Ching XT, Razali R, et al.
    PLoS One, 2016;11(6):e0157901.
    PMID: 27355363 DOI: 10.1371/journal.pone.0157901
    Toxoplasmosis is a widespread parasitic infection by Toxoplasma gondii, a parasite with at least three distinct clonal lineages. This article reports the whole genome sequencing and de novo assembly of T. gondii RH (type I representative strain), as well as genome-wide comparison across major T. gondii lineages. Genomic DNA was extracted from tachyzoites of T. gondii RH strain and its identity was verified by PCR and LAMP. Subsequently, whole genome sequencing was performed, followed by sequence filtering, genome assembly, gene annotation assignments, clustering of gene orthologs and phylogenetic tree construction. Genome comparison was done with the already archived genomes of T. gondii. From this study, the genome size of T. gondii RH strain was found to be 69.35Mb, with a mean GC content of 52%. The genome shares high similarity to the archived genomes of T. gondii GT1, ME49 and VEG strains. Nevertheless, 111 genes were found to be unique to T. gondii RH strain. Importantly, unique genes annotated to functions that are potentially critical for T. gondii virulence were found, which may explain the unique phenotypes of this particular strain. This report complements the genomic archive of T. gondii. Data obtained from this study contribute to better understanding of T. gondii and serve as a reference for future studies on this parasite.
    Matched MeSH terms: Toxoplasmosis/genetics*
  17. Long term maintenance of Toxoplasma gondii (Rh strain) in Vero cell line and use of harvested antigens for immunodiagnosis
    Suresh K, Mak JW, Yong HS
    Southeast Asian J Trop Med Public Health, 1991 Dec;22 Suppl:124-8.
    PMID: 1822869
    Thirty in vitro serial passages of Toxoplasman gondii cultures in Vero cell line performed once in every five days had a mean increase in parasite count of 74.4 +/- 14.8 times from that of initial counts. Long term cultures in Vero cell line did not alter the virulence of the parasite. The good correlation (r = 0.99) between the IFA titer and ELISA OD values using the parasite antigens from in vitro sources indicates that long term maintenance of T. gondii in culture does not affect significantly the ability to recognize antibodies to surface and soluble antigens. The results also show that soluble antigens containing host cells can be directly used for immunodiagnostic purposes without purification. The in vitro maintenance of T. gondii is safer and cheaper when compared to the in vivo method.
    Matched MeSH terms: Toxoplasmosis, Animal/diagnosis*
  18. Current public health status of some food-borne parasitic zoonoses in Malaysia
    Singh KI
    Southeast Asian J Trop Med Public Health, 1991 Dec;22 Suppl:11-5.
    PMID: 1822865
    Matched MeSH terms: Toxoplasmosis/epidemiology
  19. Prevalence of antibodies including IgM to Toxoplasma gondii in Malaysians
    Thomas V, Sinniah B, Yap PL
    Southeast Asian J Trop Med Public Health, 1980 Mar;11(1):119-25.
    PMID: 6996108
    A total of 736 sera collected from cord blood babies, children and adults of both sexes and of different age groups in Malaysia were tested using indirect fluorescent antibody technique for Toxoplasma antibodies. The RH strain of Toxoplasma gondii zoites were used as antigen. One hundred and twenty five sera which were reactive at 1:64 or high titres were tested with IgM specific conjugate. Results of the present studies showed that the prevalence of Toxoplasma antibody was highest among the Malays and lowest among children than among adults. The significance of Toxoplasma specific IgM was discussed.
    Matched MeSH terms: Toxoplasmosis/epidemiology
  20. Demonstration of antigenic similarities and variations in excretory/secretory antigens of Toxoplasma gondii
    Rahmah N, Anuar AK
    Biochem Biophys Res Commun, 1992 Aug 31;187(1):294-8.
    PMID: 1520310
    C57BL/6 mice were orally infected with different doses of cysts of ME49 strain of Toxoplasma gondii to produce groups of acutely and chronically infected mice. Sera were obtained at different periods post-infection. SDS-PAGE was ran with excretory/secretory antigens of ME49 and RH strains of T. gondii, followed by Western blot analyses using the above sera and anti- IgA, IgM, IgG as conjugates. The SDS-PAGE profiles of the two antigens were similar. However the antigenic bands showed variations in all blots, most evidently in IgA blots of chronic sera. IgG blots showed greatest similarities in reactive bands. In IgM blots, more common bands were shown in chronic sera than in acute sera. Variations and similarities in prominence of some bands and time of their appearance were also noted, especially in IgM and IgG blots of chronic sera. Thus antigenic variations and similarities are present in excretory/secretory products of different strains of T. gondii.
    Matched MeSH terms: Toxoplasmosis, Animal/immunology*
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