Displaying publications 101 - 120 of 121 in total

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  1. Fulltext Identification and real-time expression analysis of selected Toxoplasma gondii in-vivo induced antigens recognized by IgG and IgM in sera of acute toxoplasmosis patients
    Amerizadeh A, Khoo BY, Teh AY, Golkar M, Abdul Karim IZ, Osman S, et al.
    BMC Infect Dis, 2013;13:287.
    PMID: 23800344 DOI: 10.1186/1471-2334-13-287
    Toxoplasma gondii is an obligate intracellular zoonotic parasite of the phylum Apicomplexa which infects a wide range of warm-blooded animals, including humans. In this study in-vivo induced antigens of this parasite was investigated using in-vivo induced antigen technology (IVIAT) and pooled sera from patients with serological evidence of acute infection.
  2. Fulltext Evaluation of Entamoeba histolytica recombinant phosphoglucomutase protein for serodiagnosis of amoebic liver abscess
    Ning TZ, Kin WW, Noordin R, Cun ST, Chong FP, Mohamed Z, et al.
    BMC Infect Dis, 2013;13:144.
    PMID: 23514636 DOI: 10.1186/1471-2334-13-144
    Amoebic liver abscess (ALA) is the most frequent clinical presentation of extra-intestinal amoebiasis. The diagnosis of ALA is typically based on the developing clinical symptoms, characteristic changes on radiological imaging and serology. Numerous serological tests have been introduced for the diagnosis of ALA, either detecting circulating amoebic antigens or antibodies. However those tests show some pitfalls in their efficacy and/or the preparation of the tests are costly and tedious. The commercial IHA kit that used crude antigen was reported to be useful in diagnosis of ALA, however high antibody background in endemic areas may cause problems in its interpretation. Thus, discovery of well-defined antigen(s) is urgently needed to improve the weaknesses of current serodiagnostic tests.
  3. Identification of Toxoplasma gondii in-vivo induced antigens by cDNA library immunoscreening with chronic toxoplasmosis sera
    Amerizadeh A, Idris ZM, Khoo BY, Kotresha D, Yunus MH, Karim IZ, et al.
    Microb Pathog, 2013 Jan;54:60-6.
    PMID: 23044055 DOI: 10.1016/j.micpath.2012.09.006
    Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii. Chronically-infected individuals with a compromised immune system are at risk for reactivation of the disease. In-vivo induced antigen technology (IVIAT) is a promising method for the identification of antigens expressed in-vivo. The aim of the present study was to apply IVIAT to identify antigens which are expressed in-vivo during T. gondii infection using sera from individuals with chronic toxoplasmosis. Forty serum samples were pooled, pre-adsorped against three different preparations of antigens, from each in-vitro grown T. gondii and Escherichia coli XLBlue MRF', and then used to screen a T. gondii cDNA expression library. Sequencing of DNA inserts from positive clones showed eight open reading frames with high homology to T. gondii genes. Expression analysis using quantitative real-time PCR showed that SAG1-related sequence 3 (SRS3) and two hypothetical genes were up-regulated in-vivo relative to their expression levels in-vitro. These three proteins also showed high sensitivity and specificity when tested with individual serum samples. Five other proteins namely M16 domain peptidase, microneme protein, elongation factor 1-alpha, pre-mRNA-splicing factor and small nuclear ribonucleoprotein F had lower RNA expression in-vivo as compared to in-vitro. SRS3 and the two hypothetical proteins warrant further investigation into their roles in the pathogenesis of toxoplasmosis.
  4. Fulltext Detection of Entamoeba histolytica in experimentally induced amoebic liver abscess: comparison of three staining methods
    Ning TZ, Kin WW, Mustafa S, Ahmed A, Noordin R, Cheong TG, et al.
    Asian Pac J Trop Biomed, 2012 Jan;2(1):61-5.
    PMID: 23569836 DOI: 10.1016/S2221-1691(11)60191-3
    To compare the efficacy of three different tissue stains, namely haematoxylin and eosin (H&E), periodic-acid Schiff (PAS) and immunohistochemical (IHC) stains for detection of Entamoeba histolytica (E. histolytica) trophozoites in abscessed liver tissues of hamster.
  5. IgG avidity Western blot using Toxoplasma gondii rGRA-7 cloned from nucleotides 39-711 for serodiagnosis of acute toxoplasmosis
    Deshpande PS, Kotresha D, Noordin R, Yunus MH, Saadatnia G, Golkar M, et al.
    Rev Inst Med Trop Sao Paulo, 2013 4 9;55(2):79-83.
    PMID: 23563759
    Toxoplasmosis is an important cause of congenital infection. The present study was performed to evaluate the usefulness of recombinant (r) GRA-7 cloned from nucleotides (n) 39-711 in discriminating between acute and chronic toxoplasmosis. First, commercial IgM, IgG and IgG avidity ELISAs were used to determine the serological profile of the sera. Serum samples were from 20 symptomatic patients with acute infection (low IgG avidity, IgM positive), 10 with chronic infection (high IgG avidity, IgM negative) and 10 with indeterminate IgG avidity (IgM positive) which were tested for IgG avidity status with an in-house developed IgG avidity Western blot using the rGRA-7 recombinant antigen. All 20 sera from cases of probable acute infection showed bands which either faded out completely or reduced significantly in intensity after treatment with 8 M urea, whereas the band intensities of the 10 serum samples from chronic cases remained the same. Of the 10 sera with indeterminate IgG avidity status, after treatment with 8 M urea the band intensities with six sera remained the same, two sera had completely faded bands and another two sera had significantly reduced band intensities. Discrimination between acute and chronic toxoplasmosis was successfully performed by the in-house IgG avidity Western blot.
  6. Parallel ELISAs using crude soluble antigen and excretory-secretory antigen for improved serodiagnosis of amoebic liver abscess
    Wong WK, Foo PC, Olivos-Garcia A, Noordin R, Mohamed Z, Othman N, et al.
    Acta Trop, 2017 Aug;172:208-212.
    PMID: 28506795 DOI: 10.1016/j.actatropica.2017.05.017
    Crude soluble antigen (CSA) produced from Entamoeba histolytica trophozoite is conventionally used for serodiagnosis of invasive amoebiasis. However, high background seropositivities by CSA-assay in endemic areas complicate the interpretation of positive result in clinical settings. Instead, incorporating a second assay which indicates active or recent infection into the routine amoebic serology could possibly complement the limitations of CSA-assay. Hence, the present study aimed to evaluate the diagnostic efficacies of indirect ELISAs using CSA and excretory-secretory antigen (ESA) for serodiagnosis of amoebic liver abscess (ALA). Reference standard for diagnosis of ALA at Hospital Universiti Sains Malaysia is based on clinical presentation, radiological imaging and positive indirect haemagglutination assay (titer ≥256). Five groups of human serum samples collected from the hospital included Group I - ALA diagnosed by the reference standard and pus aspirate analysis using real-time PCR (n=10), Group II - ALA diagnosed by the reference standard only (n=41), Group III - healthy control (n=45), Group IV - other diseases control (n=51) and Group V - other infectious diseases control (n=31). For serodiagnosis of ALA serum samples (Group I and II), CSA-ELISA showed sensitivities of 100% for both groups, while ESA-ELISA showed sensitivities of 100% and 88%, respectively. For serodiagnosis of non-ALA serum samples (Group III, IV and V), CSA-ELISA showed specificities of 91%, 75% and 100%, respectively; while ESA-ELISA showed specificities of 96%, 98% and 100%, respectively. Indirect ELISAs using CSA and ESA have shown distinct strength for serodiagnosis of ALA, in terms of sensitivity and specificity, respectively. In conclusion, parallel analysis by both assays improved the overall efficacies of amoebic serology as compared to either single assay.
  7. Evaluation of a Rapid IgG4 Lateral Flow Dipstick Test to Detect Strongyloides stercoralis Infection in Northeast Thailand
    Noordin R, Anuar NS, Juri NM, Wongphutorn P, Ruantip S, Kopolrat KY, et al.
    Am J Trop Med Hyg, 2021 07 08;105(3):688-691.
    PMID: 34237022 DOI: 10.4269/ajtmh.21-0317
    Strongyloides stercoralis affects more than half a billion people worldwide, and hyperinfection in immunocompromised patients can be fatal. Elimination of this neglected tropical disease requires field-applicable diagnostic tools. We conducted a laboratory evaluation of a lateral flow rapid dipstick test (SsRapid™) using sera samples from a Strongyloides-endemic area in northeast Thailand. Group 1 was S. stercoralis-positive and larvae- and/or antibody-positive (according to the IgG ELISA) (N = 100). Group 2 had negative fecal examination and IgG ELISA results (N = 25). Group 3 had other parasitic infections and negative IgG ELISA results (N = 25). The results showed good diagnostic sensitivity (82%) and excellent specificity (96%). Suggested improvements in the SsRapid™ test include increased diagnostic sensitivity and conversion to the more robust cassette format. Field studies should be performed as well.
  8. Fulltext Multi-Laboratory Evaluation of a Lateral Flow Rapid Test for Detection of Amebic Liver Abscess
    Noordin R, Yunus MH, Saidin S, Mohamed Z, Fuentes Corripio I, Rubio JM, et al.
    Am J Trop Med Hyg, 2020 12;103(6):2233-2238.
    PMID: 32996457 DOI: 10.4269/ajtmh.20-0348
    Independent evaluations of XEh Rapid®, an IgG4-based rapid dipstick test, were performed to assess its diagnostic performance to detect amebic liver abscess (ALA) using 405 samples at seven laboratories in four countries. The test showed high diagnostic specificity (97-100%) when tested with samples from healthy individuals (n = 100) and patients with other diseases (n = 151). The diagnostic sensitivity was tested with a total of 154 samples, and the results were variable. It was high in three laboratories (89-94%), and moderate (72%) and low (38%) in two other laboratories. Challenges and issues faced in the evaluation process are discussed. Nevertheless, XEh Rapid is promising to be developed into a point-of-care test in particular for resource-limited settings, and thus merits further confirmation of its diagnostic sensitivity.
  9. Fulltext Diagnostic Potential of an IgE-ELISA in Detecting Strongyloidiasis
    Ahmad H, Balachandra D, Arifin N, Nolan TJ, Lok JB, Hayat Khan A, et al.
    Am J Trop Med Hyg, 2020 12;103(6):2288-2293.
    PMID: 32996454 DOI: 10.4269/ajtmh.20-0265
    Strongyloides stercoralis infection is prevalent worldwide and can cause lifelong infection in immunocompetent individuals, and potentially death in immunosuppressed patients. The diagnosis is hindered by the low sensitivity of microscopic examination, thus making serology an important complementary test to improve the detection rate. However, there were reports that some Strongyloides-infected individuals were negative with specific IgG and IgG4 assays, and other helminth infections were positive with commercial Strongyloides IgG-ELISAs. Thus, there is a need to develop better serodiagnostic methods for strongyloidiasis. We investigated the diagnostic potential of IgE-ELISAs using Strongyloides larval lysate. Sera from two groups infected with Strongyloides served as the positive reference, that is, 1) positive by commercial IgG-ELISAs and IgG4 rapid test, and stool samples positive by microscopy and/or PCR (group IA; n = 20); and 2) negative by IgG-ELISAs and IgG4 rapid test, but stool samples were PCR positive (group IB sera; n = 11). Sera from another two groups served as negative reference (controls), that is, 1) infected with other parasites (group II; n = 73) and 2) healthy donors (group III; n = 22). Results showed a 100% diagnostic sensitivity in detecting sera from groups IA and IB. The latter group of individuals probably had early infection because their IgG and IgG4 assays were negative. The optical density values of group IB sera were also significantly lower than those of group IA (P < 0.003). The IgE-ELISA was 100% specific when tested against sera from groups II and III. This study highlights the diagnostic potential of IgE-ELISA using larval lysate to detect strongyloidiasis, especially those with probable early infection.
  10. Fulltext Diagnostic value of urinary and serum IgG antibodies in evaluating drug treatment response in strongyloidiasis assessed by fecal examination and digital droplet PCR
    Wongphutorn P, Kopolrat KY, Worasith C, Eamudomkarn C, Hongsrichan N, Pitaksakulrat O, et al.
    PLoS One, 2024;19(12):e0306732.
    PMID: 39625913 DOI: 10.1371/journal.pone.0306732
    Detection of Strogyloides-specific IgG antibodies in urine and serum has been used in diagnostic and epidemiological studies on strongyloidiasis. However, the usefulness of these assays in assessing responses to anthelmintic treatment is unclear. Thus, we evaluated the diagnostic performance and temporal profiles of Strongyloides-specific IgG antibodies in a cohort of participants at baseline and post-treatment. The participants were prospectively screened for baseline parasitic infections by fecal examination [agar plate culture technique (APCT) and formalin-ethyl acetate concentration technique (FECT)] and digital droplet polymerase reaction (ddPCR) for Strongyloides stercoralis. At each sampling point, Strongyloides-specific IgG in urine and serum were measured by an in-house S. ratti-based enzyme-linked immunosorbent assay (ELISA). At baseline, 169 of 351 participants (48.1%) had S. stercoralis infection by the combined fecal examination and ddPCR. The diagnostic sensitivities of IgG in urine and serum were 91.1% and 88.2%, respectively. The participants were given treatment with a single oral dose of ivermectin (IVM, 200 μg/kg) and were followed up by fecal and immunological diagnosis at 3 to 18 months post-treatment. The cure rate of IVM treatment evaluated by APCT and ddPCR was 88.3% at three months post-treatment. The profiles of IgG in urine in the curative treatment group showed a significant trend of decline with time post-treatment (Kruskal-Wallis test = 113.4-212.6, p value < 0.0001) and the lowest levels were seen 12 months post-treatment. The treatment response (> 50% reduction in urinary IgG antibody units) was 100%, and conversion from positive to negative results was 65.4%. The treatment response and conversion to negative assessed by serum IgG-ELISA were similar to those by urine IgG-ELISA. The results from this long-term diagnostic study highlight the utility of urinary IgG and serum IgG for screening and monitoring treatment outcomes in strongyloidiasis.
  11. Fulltext A pentaplex real-time polymerase chain reaction assay for detection of four species of soil-transmitted helminths
    Basuni M, Muhi J, Othman N, Verweij JJ, Ahmad M, Miswan N, et al.
    Am J Trop Med Hyg, 2011 Feb;84(2):338-43.
    PMID: 21292911 DOI: 10.4269/ajtmh.2011.10-0499
    Soil-transmitted helminth infections remain a major public health burden in low- and middle-income countries. The traditional diagnosis by microscopic examination of fecal samples is insensitive and time-consuming. In this study, a pentaplex real-time polymerase chain reaction (PCR) was evaluated for the simultaneous detection of Ancylostoma, Necator americanus, Ascaris lumbricoides, and Strongyloides stercoralis. The results were compared with those obtained by conventional parasitological diagnostic methods. Real-time PCR was positive in 48 of 77 samples (62.3%) and microscopic examination was positive in six samples (7.8%) only (P < 0.05). In conclusion, the real-time PCR assay described in this study provides a specific and sensitive diagnostic tool for the detection of these four helminth species in epidemiological studies and monitoring of treatment programs.
  12. Fulltext Examination of Diagnostic Performance of New IgG4 Rapid Test Compared with IgG- and IgG4-ELISAs to Investigate Epidemiology of Strongyloidiasis in Northeast Thailand
    Wongphutorn P, Noordin R, Anuar NS, Worasith C, Kopolrat KY, Homwong C, et al.
    Am J Trop Med Hyg, 2024 Feb 07;110(2):254-262.
    PMID: 38190756 DOI: 10.4269/ajtmh.23-0518
    Strongyloidiasis, caused by Strongyloides stercoralis, is a neglected tropical disease with a global distribution. The infection can be fatal in immunocompromised individuals, and accurate diagnosis leading to timely treatment can save lives. Serodiagnosis is a sensitive method for diagnosis and is recommended for screening high-risk individuals. A point-of-care rapid test will facilitate the screening activities, especially in low-resource settings. This study aims to apply a new IgG4 immunochromatographic test using S. stercoralis recombinant antigen (SsRapid® cassette test) and to compare it with in-house IgG and IgG4 enzyme-linked immunosorbent assays (IgG- and IgG4-ELISAs) using native Strongyloides ratti antigen to investigate the epidemiology of strongyloidiasis in northeast Thailand. A total of 300 people participated, with 136 males and 164 females of a similar mean age. The reference tests were fecal examinations using the formalin-ethyl acetate concentration technique and an agar plate culture technique. The prevalence of S. stercoralis determined by SsRapid (81.7%) was significantly higher than that by fecal examinations (43.3%) or by antibody detection by IgG-ELISA (53.0%) or IgG4-ELISA (44.0%). The diagnostic sensitivities of SsRapid, IgG-ELISA, and IgG4-ELISA were found to be 93.9%, 77.7%, and 63.1%, respectively. The rate of positive tests by the SsRapid was significantly correlated to the levels of Strongyloides-specific IgG4 and IgG antibodies. By all diagnostic methods, male participants had a significantly higher prevalence of strongyloidiasis than females. Age was significantly associated with the concentration of specific serum IgG but not with the SsRapid grading score. In conclusion, SsRapid was shown to be a sensitive and valuable diagnostic test for the epidemiology study of strongyloidiasis.
  13. Fulltext Entamoeba histolytica acetyl-CoA synthetase: biomarker of acute amoebic liver abscess
    Huat LB, Garcia AO, Ning TZ, Kin WW, Noordin R, Azham SS, et al.
    Asian Pac J Trop Biomed, 2014 Jun;4(6):446-50.
    PMID: 25182945 DOI: 10.12980/APJTB.4.2014C1169
    To characterize the Entamoeba histolytica (E. histolytica) antigen(s) recognized by moribound amoebic liver abscess hamsters.
  14. Parasitic infections in Malaysian aborigines with pulmonary tuberculosis: a comparative cross-sectional study
    Wong WK, Mohd-Nor N, Noordin R, Foo PC, Mohamed Z, Haq JA, et al.
    Parasitol Res, 2019 Sep;118(9):2635-2642.
    PMID: 31363922 DOI: 10.1007/s00436-019-06406-7
    The geographical distribution of tuberculosis (TB) overlaps with various parasitic infections. Uncovering the characteristics of coinfecting parasites that potentially affect the host susceptibility to TB is pertinent as it may provide input to current TB therapeutic and prophylactic measures. The present study was aimed at examining the types of parasitic infections in TB patients and healthy TB contacts (HC) in Orang Asli, Malaysian aborigines, who dwelled in the co-endemic areas. Stool and serum samples were collected from Orang Asli who fulfilled the selection criteria and provided written informed consents. Selected parasitic infections in the two study groups were determined by stool examination and commercial serum antibody immunoassays. The prevalence of parasitic infections in TB and HC participants were 100% (n = 82) and 94.6% (n = 55) respectively. The parasitic infections comprised toxocariasis, trichuriasis, amoebiasis, toxoplasmosis, hookworm infection, ascariasis, strongyloidiasis, and brugian filariasis, in decreasing order of prevalence. Overall, helminth or protozoa infection did not show any significant association with the study groups. However, when the species of the parasite was considered, individuals exposed to trichuriasis and toxoplasmosis showed significant odds reduction (odds ratio (OR) 0.338; 95% confidence interval (CI) 0.166, 0.688) and odds increment (OR 2.193; 95% CI 1.051, 4.576) to have active pulmonary TB, respectively. In conclusion, trichuriasis and toxoplasmosis may have distinct negative and positive associations respectively with the increase of host susceptibility to TB.
  15. Prevalence and risk factors of Strongyloides stercoralis infection among Orang Asli schoolchildren: new insights into the epidemiology, transmission and diagnosis of strongyloidiasis in Malaysia
    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.
  16. Fulltext Socio-demographic determinants of Toxoplasma gondii seroprevalence in migrant workers of Peninsular Malaysia
    Sahimin N, Lim YAL, Ariffin F, Behnke JM, Basáñez MG, Walker M, et al.
    Parasit Vectors, 2017 May 15;10(1):238.
    PMID: 28506241 DOI: 10.1186/s13071-017-2167-8
    BACKGROUND: The number of migrants working in Malaysia has increased sharply since the 1970's and there is concern that infectious diseases endemic in other (e.g. neighbouring) countries may be inadvertently imported. Compulsory medical screening prior to entering the workforce does not include parasitic infections such as toxoplasmosis. Therefore, this study aimed to evaluate the seroprevalence of T. gondii infection among migrant workers in Peninsular Malaysia by means of serosurveys conducted on a voluntary basis among low-skilled and semi-skilled workers from five working sectors, namely, manufacturing, food service, agriculture and plantation, construction and domestic work.

    METHODS: A total of 484 migrant workers originating from rural locations in neighbouring countries, namely, Indonesia (n = 247, 51.0%), Nepal (n = 99, 20.5%), Bangladesh (n = 72, 14.9%), India (n = 52, 10.7%) and Myanmar (n = 14, 2.9%) were included in this study.

    RESULTS: The overall seroprevalence of T. gondii was 57.4% (n = 278; 95% CI: 52.7-61.8%) with 52.9% (n = 256; 95% CI: 48.4-57.2%) seropositive for anti-Toxoplasma IgG only, 0.8% (n = 4; 95% CI: 0.2-1.7%) seropositive for anti-Toxoplasma IgM only and 3.7% (n = 18; 95% CI: 2.1-5.4%) seropositive with both IgG and IgM antibodies. All positive samples with both IgG and IgM antibodies showed high avidity (> 40%), suggesting latent infection. Age (being older than 45 years), Nepalese nationality, manufacturing occupation, and being a newcomer in Malaysia (excepting domestic work) were positively and statistically significantly associated with seroprevalence (P 

  17. 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.
  18. Fulltext Comparison of Two Serological Assays in Detecting Strongyloides Infection in Immunocompromised Patients
    Osman E, Amin NA, Noon TPM, Lahat SNH, Rosli MS, Sham SF, et al.
    Am J Trop Med Hyg, 2022 Jul 25;107(3):636-9.
    PMID: 35895335 DOI: 10.4269/ajtmh.22-0076
    Strongyloides infection may develop into fatal hyperinfection and dissemination syndrome in immunocompromised hosts. Despite suboptimal specificity issues, the detection of IgG antibodies by ELISA has been central in the serodiagnosis of Strongyloides infection. Recently, an IgG4-based lateral-flow test (SsRapid) using recombinant NIE (rNIE) protein with good diagnostic performance has been reported. This study assessed the result concordance between a commercial IgG-ELISA and the SsRapid. Additionally, we determined the Strongyloides seroprevalence and its association with clinical manifestations. Immunocompromised patients (N = 200) were from Hospital Canselor Tuanku Muhriz, Kuala Lumpur, Malaysia, and were diagnosed with HIV/AIDS, hematological malignancy, and solid organ cancers. Their plasma samples were tested using a commercial IgG-ELISA and SsRapid. A fair concordance (κ = 0.27-0.33; P < 0.05) among the tests was demonstrated. The SsRapid exhibited a significantly higher (P < 0.05) seroprevalence (10.5% [21/200]) compared with IgG-ELISA (7.5% [15/200]). After adsorption with rNIE, all SsRapid-positive samples tested negative with the rapid test, thus showing binding specificity. There was no significant association with clinical manifestations. This study revealed that SsRapid is a useful diagnostic tool for Strongyloides infection, and there is a notable seroprevalence among the immunocompromised patients.
  19. Fulltext Partially purified Strongyloides ratti antigen improved the diagnostic performance of strongyloidiasis by enzyme-linked immunosorbent assay (ELISA) and immunochromatographic test (ICT)
    Wongphutorn P, Worasith C, Kopolrat KY, Eamudomkarn C, Pitaksakulrat O, Hongsrichan N, et al.
    Microbiol Spectr, 2025 Feb 04.
    PMID: 39902967 DOI: 10.1128/spectrum.02368-24
    Strongyloides stercoralis infection is a neglected tropical disease with a global distribution. Serodiagnosis is a sensitive method, but improving its performance and simplifying into a point-of-care test (POCT) are needed. This study aimed to improve the diagnostic performance of serological tests using partially purified Strongyloides ratti antigen in an enzyme-linked immunosorbent assay (ELISA) and an immunochromatographic test (ICT). Crude S. ratti antigen was purified by an IgG affinity column to partition the antigen into flow-through, washing fraction (WF), and elution fractions. Optimized ELISA and ICT using crude and antigen fractions were used to analyze sera from three groups of subjects. Group 1 comprised subjects with proven strongyloidiasis, Group 2 were subjects with other parasitic infections, and Group 3 were negative parasitic infections. The diagnostic performance and Kappa agreement of the serological tests were analyzed and compared, using larvae detection as the reference test (fecal examination). The results showed that the WF was the most efficient antigen in terms of sensitivity and specificity, as determined by the ELISA and ICT. Kappa's agreement between fecal examination and WF-ELISA was moderate (Kappa = 0.52), and WF-ICT was almost perfect (Kappa = 0.94). The WF antigen reduced cross-reactivity to other parasitic infections, that is, Opisthorchis viverrini, Taenia spp., and hookworms, compared to crude S. ratti antigen when assessed by ELISA and ICT. We concluded that the WF of purified S. ratti improved the ELISA and ICT diagnostic performance, and the latter assay format could be used as a POCT for screening and controlling strongyloidiasis.IMPORTANCEThis study aimed to improve the serological diagnosis of strongyloidiasis, a disease caused by infection with the intestinal nematode Strongyloides stercoralis, by evaluating the impact of Strongyloides ratti antigen purification using an IgG affinity column for detecting parasite-specific IgG in serum via enzyme-linked immunosorbent assay (ELISA) and immunochromatographic test (ICT) formats. Compared to crude S. ratti antigen, the washing fraction (WF) of the purified antigen demonstrated significantly improved sensitivity and specificity in both ELISA and ICT, achieving strong diagnostic concordance with the gold-standard fecal examination. Furthermore, the WF antigen fraction exhibited reduced cross-reactivity with coinfections caused by the liver fluke (Opisthorchis viverrini), tapeworms (Taenia spp.), and hookworms. These findings underscore antigen purification as a promising strategy to enhance the accuracy of strongyloidiasis serodiagnosis.
  20. Fulltext Diagnostics and the neglected tropical diseases roadmap: setting the agenda for 2030
    Souza AA, Ducker C, Argaw D, King JD, Solomon AW, Biamonte MA, et al.
    Trans R Soc Trop Med Hyg, 2021 01 28;115(2):129-135.
    PMID: 33169166 DOI: 10.1093/trstmh/traa118
    Accurate and reliable diagnostic tools are an essential requirement for neglected tropical diseases (NTDs) programmes. However, the NTD community has historically underinvested in the development and improvement of diagnostic tools, potentially undermining the successes achieved over the last 2 decades. Recognizing this, the WHO, in its newly released draft roadmap for NTD 2021-2030, has identified diagnostics as one of four priority areas requiring concerted action to reach the 2030 targets. As a result, WHO established a Diagnostics Technical Advisory Group (DTAG) to serve as the collaborative mechanism to drive progress in this area. Here, the purpose and role of the DTAG are described in the context of the challenges facing NTD programmes.
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