Displaying publications 1 - 20 of 125 in total

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  1. Fong MY, Lau YL, Zulqarnain M
    Biotechnol Lett, 2008 Apr;30(4):611-8.
    PMID: 18043869
    The surface antigen 2 (SAG2) gene of the protozoan parasite, Toxoplasma gondii, was cloned and extracellularly expressed in the yeast Pichia pastoris. The effectiveness of the secreted recombinant SAG2 (rSAG2-S) as a serodiagnosis reagent was assessed by western blots and ELISA. In the western blot assay, rSAG2-S reacted with all Toxoplasma-antibody positive human serum samples but not with Toxoplasma-negative samples. In the ELISA, rSAG2-S yielded sensitivity rates ranging from 80% (IgG negative, IgM positive) to 100% (IgG positive, IgM negative). In vivo experiments showed that serum from mice immunized with rSAG2-S reacted specifically with the native SAG2 of T. gondii. These mice were protected when challenged with live cells of T. gondii.
    Matched MeSH terms: Toxoplasma/genetics; Toxoplasma/immunology; Toxoplasma/metabolism*
  2. Xia NB, Lu Y, Zhao PF, Wang CF, Li YY, Tan L, et al.
    Trop Biomed, 2020 Jun 01;37(2):489-498.
    PMID: 33612818
    Toxoplasma gondii, a ubiquitous pathogen that infects nearly all warm-blooded animals and humans, can cause severe complications to the infected people and animals as well as serious economic losses and social problems. Here, one local strain (TgPIG-WH1) was isolated from an aborted pig fetus, and the genotype of this strain was identified as ToxoDB #3 by the PCR RFLP typing method using 10 molecular markers (SAG1, SAG2, alternative SAG2, SAG3, BTUB, GRA6, L358, PK1, C22-8, C29-2 and Apico). A comparison of the virulence of this isolate with other strains in both mice and piglets showed that TgPIG-WH1 was less virulent than type 1 strain RH and type 2 strain ME49 in mice, and caused similar symptoms to those of ME49 such as fever in piglets. Additionally, in piglet infection with both strains, the TgPIG-WH1 caused a higher IgG response and more severe pathological damages than ME49. Furthermore, TgPIG-WH1 caused one death in the 5 infected piglets, whereas ME49 did not, suggesting the higher virulence of TgPIG-WH1 than ME49 during piglet infection. Experimental infections indicate that the virulence of TgPIG-WH1 relative to ME49 is weaker in mice, but higher in pigs. This is probably the first report regarding a ToxoDB #3 strain from pigs in Hubei, China. These data will facilitate the understanding of genetic diversity of Toxoplasma strains in China as well as the prevention and control of porcine toxoplasmosis in the local region.
    Matched MeSH terms: Toxoplasma/genetics*
  3. Tan DS, Zaman V
    Med J Malaysia, 1973 Mar;27(3):188-91.
    PMID: 4268921
    Matched MeSH terms: Toxoplasma/immunology*
  4. Zaman V
    Med J Malaya, 1968 Mar;22(3):195-7.
    PMID: 4234355
    Matched MeSH terms: Toxoplasma/growth & development*
  5. Ge P, Ong CY, Abdalkareem AE, Khoo BY, Yuan B
    Exp Ther Med, 2021 Feb;21(2):103.
    PMID: 33335566 DOI: 10.3892/etm.2020.9535
    The presence of certain soluble factors may provide a possible selective advantage for a parasite to gradually modify cell proliferation in neighbouring cells, which may result in chronic diseases. These soluble factors present in the conditioned medium also allow the parasite to invade rapidly into more host cells. The present study aimed to determine the levels of a group of type 1 T helper (Th1) cytokines in the conditioned media of host cells infected with parasites and in IL-21-silenced colorectal cancer cells. The conditioned media of human foreskin fibroblasts (HFFs) parasitized with the RH and ME49 strains of Toxoplasma gondii for 10 days were prepared, and subsequently the levels of the Th1 cytokines in the conditioned media were determined by ELISA. HFFs were incubated with the growth media containing selected soluble factors, and cell proliferation markers were subsequently analysed by reverse transcription-quantitative PCR. The mRNA expression level of cell proliferation markers was also examined in IL-21-silenced HCT116 cells, where the levels of soluble factors in the conditioned media were also determined as aforementioned. The results of the present study demonstrated that HFFs parasitized with ME49 released elevated levels of IFN-γ and lower levels of IL-18 into the conditioned medium compared with the controls. These phenomena were not observed in the conditioned medium of HFFs parasitized with RH. Similar levels of these soluble factors were also detected in the conditioned medium of IL-21-silenced HCT116 cells. The results of the present study also revealed that Ki67 and proliferating cell nuclear antigen mRNA expression was altered in host cells incubated with various levels of IFN-γ and IL-18, as well as in IL-21-silenced HCT116 cells compared with the respective controls. In conclusion, the current study provided preliminary evidence on the fundamental molecular mechanisms of host-parasite interactions that result in chronic diseases, which may aid in the treatment of these diseases in the relevant endemic regions.
    Matched MeSH terms: Toxoplasma
  6. Suresh K, Mak JW, Yong HS
    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: Toxoplasma/growth & development*; Toxoplasma/immunology; Toxoplasma/pathogenicity
  7. Suresh K, Mak JW, Yong HS
    PMID: 1818400
    Matched MeSH terms: Toxoplasma/growth & development*
  8. Ling LY, Ithoi I, Yik FM
    PMID: 20578535
    SAG2 is one of the major surface antigens of the intracellular protozoan parasite Toxoplasma gondii. In the present study, truncated recombinant SAG2(S) and full length recombinant SAG2(T) of T. gondii were optimally produced (approximately 15 mg/liter) in Pichia pastoris expression system using BMMY medium at pH 3, 25 degrees C in 0.5-1% methanol and a time-course of 1-2 days. The recombinant proteins were purified using a commercial gel filtration purification system obtaining approximately 33% recovery. The purified SAG2(S) and SAG2(T) showed molecular masses of 45 and 36 kDa by SDS-PAGE, respectively. The recombinant proteins were evaluated by Western blotting with patients' sera and demonstrated 90% sensitivity and 100% specificity for detection of toxoplasmosis. This study provided a means for large-scale expression and purification of SAG2, which should be useful for diagnosis of toxoplasmosis.
    Matched MeSH terms: Toxoplasma/isolation & purification*
  9. Nissapatorn V, Leong TH, Lee R, Init-Ithoi, Ibrahim J, Yen TS
    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: Toxoplasma/isolation & purification
  10. Thomas V, Sinniah B, Yap PL
    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: Toxoplasma/immunology*
  11. Khairul Anuar A, Rahmah N, Dighe VC, Zurainee MN, Suresh K, Yano A
    JUMMEC, 1999;4:34-38.
    In vitro lymphocyte proliferative response of peripheral blood leucocytes (PBL) to purified Toxoplasma gondii antigen were evaluated by 3[H] methyl thymidine incorporation in patients acutely and chronically infected with Toxoplama gondii. PBL from three patients with acute sylnptonlatic toxoplaslnosis showed no response to T. gondii antigen during the emergence of anti-Toxoplasma 1gM antibodies and the response returned as the infection became chronic. Lymphocytes of twelve chronically-infected patients responded positively to the antigen. In all patients the lymphocyte proliferative response to the mitogen, Concanavalill A (Con A) was normal. Analysis of Toxoplasma proliferative response of PBL from a patient with acute toxoplasrnosis showed that CD8+ cells were responsible for induction of suppression while the response during the chronic infection was lnediated by CD4+ cells. In human toxoplasmosis there was antigen-specific lymphocyte unresponsiveness during the acute phase of the infection and it appears that the initnunesuppression was mediated by CD8+ cells. KEYWORDS: Toxoplasmosis-lymphocyte blastogenesis-antigen specific-CD4+, CD8+
    Matched MeSH terms: Toxoplasma
  12. Yahaya N
    PMID: 1822863
    Various studies on toxoplasmosis in Malaysia have shown that specific antibodies to Toxoplasma gondii are common among Malaysians. Among the ethnic groups, the Malays have the highest prevalence rate followed by Indians, Orang Aslis (aborigines) and Chinese. Antibody is acquired early in life and increases with age. There is no significant difference in the prevalence rate between males and females. The disease is apparently more prevalent among rural dwellers and those in the lower socioeconomic group. It appears that the prevalence rate is also influenced by environmental conditions, occupation, diet and cultural habits. Studies with animals have shown the presence of antibody to T. gondii, but this does not seem to be the source of infection since Malaysians normally cook their meat well.
    Matched MeSH terms: Toxoplasma/immunology*
  13. Tao Y, Shen C, Zhang Y, Zhao X, Leow CY, Wu J, et al.
    Acta Trop, 2023 Feb;238:106783.
    PMID: 36455636 DOI: 10.1016/j.actatropica.2022.106783
    BACKGROUND: The scale-up of zoonoses prevention control and eradication in China, coupled with numerous academic articles in Chinese journals has led to the development of new tools and strategies aimed at further consolidating parasite control goals. As a result, there is a growing need for an up-to-date understanding of the research progress and prevention and control experience of parasitic diseases in China.

    METHODS: To understand the research status of schistosomiasis and toxoplasmosis in China, academic articles published in Chinese journals from 1980 to 2021 were retrieved from China National Knowledge Infrastructure (CNKI) and Wanfang databases. The Bibliographic Items Co-occurrence Matrix Builder (BICOMB) software was used to extract and analyze the keyword frequencies. The 'K/A ratio' as the frequency of a keyword that occurred in all the articles within a certain time stage was calculated to compare the popularity of the same keyword in different time stages. Keyword co-occurrence network maps were constructed by VOSviewer software.

    RESULTS: A total of 18,508 articles in the research field of Schistosoma and 13,289 articles in the field of Toxoplasma gondii were included. Results in both fields showed some similarities: the annual number of articles presented an increasing trend before entering the 21st century and decreased rapidly in recent years. Two opposite changing trends of keyword frequency could be observed in the K/A ratio analysis: the K/A ratios of 'Surveillance' and 'Infection' continuously increased over time, while those of 'Schistosoma mansoni' and 'Mesenteric lymph nodes' decreased. The diversification of keyword co-occurrence networks could be observed in the co-occurrence network maps.

    CONCLUSIONS: This bibliometric analysis reveals trends in research themes in the fields of Schistosoma and Toxoplasma gondii from 1980 to 2021, presenting China's experience such as a high degree of government involvement and multidisciplinary participation in schistosomiasis and toxoplasmosis control and elimination.

    Matched MeSH terms: Toxoplasma*; Toxoplasmosis*
  14. Tan LP, Megat Abd Rani PA, Sharma RSK, Syed Hussain SS, Watanabe M
    Trop Biomed, 2020 Sep 01;37(3):542-550.
    PMID: 33612769 DOI: 10.47665/tb.37.3.542
    Toxoplasma gondii, a zoonotic protozoan that has a worldwide distribution, is known to infect many warm-blooded vertebrates. The feline species including domestic cats are the definitive hosts for Toxoplama gondii and shed the infective oocyst. There is lack of information on the prevalence of Toxoplasma gondii in cats in Malaysia. The objective of this study was to determine both the seroprevalence of T. gondii and the prevalence of T. gondii DNA in cats' feces in Klang Valley, Malaysia. 198 blood and 201 fecal samples were collected from pet and stray cats from the local council, Dewan Bandaraya Kuala Lumpur (DBKL) and University Veterinary Hospital, Universiti Putra Malaysia respectively. The overall seroprevalence of Toxoplasma gondii in cats in the Klang Valley was found to be 5.5%. There was a high prevalence (10.5%) of T. gondii DNA detected in the cat fecal samples in both pet and stray cats suggestive of T. gondii oocyst shedding. Stray cats showed a higher seroprevalence and molecular prevalence of T. gondii than the pet cats. However, comparative analysis using Chi-square test showed no significant difference between both groups (P>0.05). Higher prevalence (10.5%) of cats shedding T. gondii DNA as compared to the seroprevalence (5.5%) was found in the cat population in the Klang Valley. The high prevalence of cats shedding T. gondii DNA is alarming as this may directly reflect the number of oocysts excreted into the environment posing a significant public health hazard.
    Matched MeSH terms: Toxoplasma
  15. Molan A, Nosaka K, Hunter M, Wang W
    Trop Biomed, 2019 Dec 01;36(4):898-925.
    PMID: 33597463
    Our group sought to determine the global status of T. gondii infection and to evaluate any continental and geographical trends by systematically examining the currently available epidemiological data on the prevalence of T. gondii infection. A comprehensive literature search was conducted from 10 electronic databases (Google Scholar, Science Direct, Embase, PubMed, PLOS ONE, Web of Knowledge, SciELO, MyAIS, Free Medical Journals, and Scopus) without date or language restrictions. Specific medical subject heading terms were used to search for human T. gondii seroprevalence studies that recruited subjects from general apparently healthy populations. The data were collated and analysed for both continental and global trends. The search identified 152 published studies that examined a total of 648,010 subjects. From these, 166,255 were seropositive for T. gondii infection indicating an average global seroprevalence rate of 25.7% (95% CI: 25.6 - 25.8%). The overall range of seroprevalence was determined to be 0.5 - 87.7%. African countries had the highest average seroprevalence rate of 61.4%, followed by Oceania with 38.5%, South America with 31.2%, Europe with 29.6%, USA/Canada with 17.5%, and Asia with 16.4%. Numerous environmental and human factors affect the differences in T. gondii seroprevalence rates observed between the various countries and continents. Monitoring the source and transmission may assist public health authorities to clarify the risk factors involved, as well as focus on implementing optimal state-specific health policies targeting T. gondii transmission control.
    Matched MeSH terms: Toxoplasma
  16. Aisha Khodijah Kholib Jati, Suharni Mohamad, Zeehaida Mohamed, Wan Haslindawani Wan Mahmood, Wan Muhamad Amir W Ahmad, Wan Suriana Wan Ab Rahman1
    MyJurnal
    Introduction: This preliminary cross-sectional study aimed to investigate the prevalence of toxoplasmosis among blood donors in Kelantan, Malaysia. Methods: A total of 56 blood donors were screened by an enzyme-linked immu- nosorbent assay (ELISA) for anti-T. gondii Immunoglobulin G (IgG) and Immunoglobulin M (IgM) antibodies. Positive
    T. gondii IgG and IgM were further tested for IgG avidity ELISA. All extracted deoxyribonucleic acids (DNAs) from whole blood samples were analyzed for the presence of the Toxoplasma B1 gene and the ITS1 region by polymerase chain reaction (PCR). The socio-demographic data of donors was assessed using a data collection form. Results: Out of 56 blood donors, 24 (42.86%) donors were IgG+/IgM-, and 2 (3.57%) donors were IgG+/IgM+ with one of them having a high avidity index indicating as past infection for more than 20 weeks and the other with a low avidity index indicating as recent infection within 20 weeks. None of the samples tested positive for the presence of the Toxoplasma B1 gene and the ITS1 region. A univariate analysis showed that only employment status was significantly associated with Toxoplasma seropositivity. Conclusion: The seroprevalence of toxoplasmosis among blood donors in Kelantan, Malaysia, was 46.43%. Nevertheless, direct detection by PCR showed that this parasite was absent in the blood. These results highlight that the blood donors in this study had previously been exposed to T. gondii infection. The parasite may still remain in certain tissues but does not freely circulate in the blood.
    Matched MeSH terms: Toxoplasma
  17. Wan Omar Abdullah
    MyJurnal
    Toxoplasmosis, caused by an intracellular protozoan parasite, Toxoplasma gondii, is widespread throughout the world. The disease is of major medical and veterinary importance, being a cause of congenital disease and abortion in humans and in domestic animals.[1] In addition, it has gained importance recently due to toxoplasma encephalitis in AIDS patients.[2] T. gondii was discovered 100 years ago. Its identification was rapidly followed by the recognition that it was a human pathogen. During the past 100 years, the spectrum of diseases caused by this ubiquitous pathogen has expanded to include both congenital and acute infections as well as the recognition of diseases caused by this pathogen in the immune-compromised host. Recent data on behavioural changes in animals due to chronic toxoplasmosis is leading to research on the effect of this pathogen on the behaviour of humans.[3] Experimental studies on T. gondii have resulted in it becoming a model organism for studies on host pathogen interactions. Integration of clinical and experimental data on T. gondii should continue to lead to important insights into improvements in diagnosis for clinical management and vaccine development for control of toxoplasmosis.
    Matched MeSH terms: Toxoplasma
  18. 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: Toxoplasma/drug effects*
  19. Dorny P, Van Aken D
    Ann Trop Med Parasitol, 1992 Feb;86(1):83-5.
    PMID: 1616398
    Matched MeSH terms: Toxoplasma/immunology*
  20. Ahmad N., Osman, E., Abdul Ghani, N.A., Leong, W.Y., Arzaee, M.Z., Seow, Y.Y., et al.
    Medicine & Health, 2020;15(2):108-123.
    MyJurnal
    Toksoplasmosis pendam dapat menyebabkan pelbagai gangguan hormon dan tingkah laku dalam hos terjangkit. Kami berhasrat untuk mengkaji sero-prevalens Toxoplasma gondii (T. gondii) pendam serta hubungan antara jangkitan dengan pengetahuan dan tingkah laku dalam kalangan 400 ibu hamil. Sampel plasma diuji untuk kehadiran antibodi IgG T. gondii dan soal selidik berstruktur digunakan untuk merekodkan ciri-ciri sosio-demografi responden, maklumat umum dan pengetahuan mengenai faktor risiko, gejala, masa jangkitan, pengetahuan pencegahan serta tingkah laku pencegahan toksoplasmosis. Sero-prevalensi toksoplasmosis pendam dalam wanita hamil adalah 31.8%. Kajian menunjukkan, 69.5% daripada mereka mempunyai kurang pengetahuan mengenai toksoplasmosis. Walau bagaimanapun, majoritinya (99.8%) mengamalkan tingkah laku pencegahan. Analisis regresi logistik berganda menunjukkan wanita hamil dengan tahap pendidikan rendah mempunyai hampir dua kali lebih risiko (nisbah ods terlaras: 1.91, 95% SK 1.18, 3.10; p = 0.008) untuk T. gondii IgG seropositif. Wanita hamil yang mempunyai sejarah perubatan lalu mempunyai dua kali lebih kemungkinan (nisbah ods terlaras: 2.32, 95% SK 1.32, 4.06; p = 0.003) untuk T. gondii IgG seropositif. Selain itu, wanita yang tidak pasti mengenai mod penyebaran penyakit melalui pemindahan darah mempunyai empat kali lebih ods (nisbah ods terlaras: 3.93, 95% SK 1.54, 10.01; p = 0.004) untuk sero-prevalens kronik toksoplasmosis. Wanita yang tidak pasti mengenai keperluan menghindari kucing liar mempunyai nisbah ods terlaras: 0.42 (95% SK 0.24, 0.71, p = 0.001) untuk sero-prevalens kronik toksoplasmosis. Penterjemahan pengetahuan tentang toksoplasmosis kepada amalan tingkah laku pencegahan melalui program pendidikan kesihatan adalah penting untuk mengurangkan risiko penularan penyakit ini dalam kalangan wanita hamil.
    Matched MeSH terms: Toxoplasma
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