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Fulltext Genotyping of Toxoplasma gondii isolates from wild boars in Peninsular Malaysia

Puvanesuaran VR, Noordin R, Balakrishnan V

PLoS One, 2013;8(4):e61730.
PMID: 23613920 DOI: 10.1371/journal.pone.0061730

Toxoplasma gondii is a parasitic protozoan that infects nearly one-third of the world population. The present study was done to isolate and genotype T. gondii from wild boar from forests of Pahang, Malaysia. A total of 30 wild boars' blood, heads and hearts were obtained for this study and 30 (100.0%) were found to be seropositive when assayed with modified agglutination test (MAT ≥ 6). The positive samples were inoculated into mice and T. gondii was only isolated from samples that had strong seropositivity (MAT ≥ 1:24).The isolates were subjected to PCR-RFLP analysis and all the Peninsular Malaysia isolates of T. gondii are of clonal type I.
Use of prednisolone to aid propagation of Toxoplasma gondii in mice

Puvanesuaran VR, Nowroji K, Sreenivasan S, Noordin R, Balakrishnan V

Eur Rev Med Pharmacol Sci, 2012 Aug;16(8):1028-32.
PMID: 22913152

AIM: To determine the usefulness of prednisolone in increasing the number of Toxoplasma (T.) gondii tachyzoites and bradyzoites in mice.
MATERIALS AND METHODS: The mice were water-fasted prior to being immunosuppressed with oral inoculation of prednisolone. Tachyzoites of 7T gondii RH strain were inoculated into mice and the number of the parasites in the intraperitoneal fluids was then determined at 96 hs post-infection. In addition, tachyzoites of T. gondii ME49 strains were orally introduced into mice and the number of brain cysts formed was observed by microscopic observation at 45 days post-infection.
RESULTS: T. gondii propagation was found to be significantly improved by introduction of the prednisolone (p = 0.0004); and the number of parasite showed positive correlation with the increment in dosage of prednisolone (r = 0.9051).
CONCLUSIONS: The use of prednisolone greatly improved the number of parasite formed in mice: both tachyzoite and cyst forms.
Isolation of viable Toxoplasma gondii cysts from brain samples for oral infection

Puvanesuaran VR, Ibrahim N, Noordin R, Balakrishnan V

Eur Rev Med Pharmacol Sci, 2012 Sep;16(9):1179-83.
PMID: 23047500

AIM: A method was developed to separate contaminant-free viable Toxoplasma gondii cysts from brain samples of infected mice for molecular biology studies and reinfection.
MATERIALS AND METHODS: The mice brains were homogenized and washed with phosphate buffered saline (PBS) Tween 80 prior to fractionation using 19-22% dextran solution. Finally, the supernatant was purified by two-step membrane filtration (100-160 microm and < 10 microm) to obtain pure T. gondii cyst. The isolates were analyzed through microscopic observation, qPCR and by reinfection of new batch of mice.
RESULTS: T. gondii cysts were best isolated with 21% dextran solution and two step filtration.
CONCLUSIONS: The method was observed not to disrupt the integrity of the cysts containing bradyzoites. In addition, the isolated cysts in the filtrate were found to be contaminant-free, viable and able to infect healthy mice when introduced orally; which, mimics the natural infectivity pathway.
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.
Entamoeba histolytica antigenic protein detected in pus aspirates from patients with amoebic liver abscess

Othman N, Mohamed Z, Yahya MM, Leow VM, Lim BH, Noordin R

Exp Parasitol, 2013 Aug;134(4):504-10.
PMID: 23680184 DOI: 10.1016/j.exppara.2013.05.001

Entamoeba histolytica is a causative agent of amoebic liver abscess (ALA) and is endemic in many underdeveloped countries. We investigated antigenic E. histolytica proteins in liver abscess aspirates using proteomics approach. Pus samples were first tested by real-time PCR to confirm the presence of E. histolytica DNA and the corresponding serum samples tested for E. histolytica-specific IgG by a commercial ELISA. Proteins were extracted from three and one pool(s) of pus samples from ALA and PLA (pyogenic liver abscess) patients respectively, followed by analysis using isoelectric focussing, SDS-PAGE and Western blot. Unpurified pooled serum samples from infected hamsters and pooled human amoebic-specific IgG were used as primary antibodies. The antigenic protein band was excised from the gel, digested and analysed by MALDI-TOF/TOF and LC-MS/MS. The results using both primary antibodies showed an antigenic protein band of ∼14kDa. Based on the mass spectrum analysis, putative tyrosine kinase is the most probable identification of the antigenic band.
Application of real-time polymerase chain reaction in detection of Entamoeba histolytica in pus aspirates of liver abscess patients

Othman N, Mohamed Z, Verweij JJ, Huat LB, Olivos-García A, Yeng C, et al.

Foodborne Pathog Dis, 2010 Jun;7(6):637-41.
PMID: 20132028 DOI: 10.1089/fpd.2009.0427

Entamoeba histolytica is the second major cause of liver abscess disease in humans, particularly in developing countries. Recently, DNA molecular-based methods have been employed to enhance the detection of E. histolytica in either pus or stool specimens. In this study, the results of real-time polymerase chain reaction (PCR) to detect E. histolytica DNA in pus from liver abscess cases were compared with those of indirect hemagglutination assay on the corresponding serum samples. Bacterial cultures were also performed on the pus samples for the diagnosis of pyogenic liver abscess. The real-time PCR detected E. histolytica DNA in 23 of 30 (76.7%) pus samples, when compared with 14 of 30 (46.7%) serum samples in which anti-Entamoeba antibodies were detected by indirect hemagglutination assay and 4 of 30 (13.3%) pus samples that showed bacterial infection by culture. The use of real-time PCR is a promising detection method for diagnosis and epidemiology assessment of amoebic liver abscess.
Fulltext Protein expression in sera of patients with amoebic liver abscess (ALA): potential use of haptoglobin as a surrogate disease marker

Othman N, Zainudin NS, Mohamed Z, Yahya MM, Leow VM, Noordin R

Trop Biomed, 2013 Jun;30(2):257-66.
PMID: 23959491 MyJurnal

The protein profile of serum samples from patients with amoebic liver abscess (ALA) was compared to those of normal individuals to determine their expression levels and to identify potential surrogate disease markers. Serum samples were resolved by two dimensional electrophoresis (2-DE) followed by image analysis. The up and down-regulated protein spots were excised from the gels and analysed by MS/MS. The concentration of three clusters of proteins i.e. haptoglobin (HP), α1-antitrypsin (AAT) and transferrin in serum samples of ALA patients and healthy controls were compared using competitive ELISA. In addition, serum concentrations of HP and transferrin in samples of patients with ALA and pyogenic liver abscess (PLA) were also compared. The results of the protein 2-DE expression analysis showed that HP cluster, AAT cluster, one spot each from unknown spots no. 1 and 2 were significantly up-regulated and transferrin cluster was significantly down-regulated in ALA patients' sera (p<0.05). The MS/MS analysis identified the unknown protein spot no.1 as human transcript and haptoglobin and spot no. 2 as albumin. Competitive ELISA which compared concentrations of selected proteins in sera of ALA and healthy controls verified the up-regulated expression (p<0.05) of HP and the down-regulated expression (p<0.01) of transferrin in the former, while there was no significant difference in AAT expression (p> 0.05). However, when ALA and PLA samples were compared, competitive ELISA showed significant increased concentration of HP (p<0.05) while transferrin levels were not different. In conclusion, this study showed that HP is a potential surrogate disease marker for ALA.
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.
Fulltext Development of an antigen-DNAzyme based probe for a direct antibody-antigen assay using the intrinsic DNAzyme activity of a daunomycin aptamer

Omar N, Loh Q, Tye GJ, Choong YS, Noordin R, Glökler J, et al.

Sensors (Basel), 2013;14(1):346-55.
PMID: 24379042 DOI: 10.3390/s140100346

G-Quadruplex (G-4) structures are formed when G-rich DNA sequences fold into intra- or intermolecular four-stranded structures in the presence of metal ions. G-4-hemin complexes are often effective peroxidase-mimicking DNAzymes that are applied in many detection systems. This work reports the application of a G-rich daunomycin-specific aptamer for the development of an antibody-antigen detection assay. We investigated the ability of the daunomycin aptamer to efficiently catalyze the hemin-dependent peroxidase activity independent of daunomycin. A reporter probe consisting of biotinylated antigen and daunomycin aptamer coupled to streptavidin gold nanoparticles was successfully used to generate a colorimetric readout. In conclusion, the daunomycin aptamer can function as a robust alternative DNAzyme for the development of colorimetric assays.
Generation and selection of naïve Fab library for parasitic antigen: Anti-BmSXP antibodies for lymphatic filariasis

Omar N, Hamidon NH, Yunus MH, Noordin R, Choong YS, Lim TS

Biotechnol Appl Biochem, 2018 May;65(3):346-354.
PMID: 28833498 DOI: 10.1002/bab.1591

Phage display has been applied successfully as a tool for the generation of monoclonal antibodies (mAbs). Naive antibody libraries are unique as they are able to overcome several limitations associated with conventional mAb generation methods like the hybridoma technology. Here, we performed an in vitro selection and generation of Fab antibodies against Brugia malayi SXP protein (BmSXP), a recombinant antigen for the detection of lymphatic filariasis. We developed a naïve multi ethnic Fab antibody library with an estimated diversity of 2.99 × 109 . The antibody library was used to screen for mAbs against BmSXP recombinant antigen. Soluble monoclonal Fab antibodies against BmSXP were successfully isolated from the naïve library. The Fab antibodies obtained were expressed and analyzed to show its binding capability. The diversity obtained from a pool of donors from various ethnic groups allowed for a diverse antibody library to be generated. The mAbs obtained were also functional in soluble form, which makes it useful for further downstream applications. We believe that the Fab mAbs are valuable for further studies and could also contribute to improvements in the diagnosis of filariasis.
Fulltext Laboratory detection of strongyloidiasis: IgG-, IgG4 - and IgE-ELISAs and cross-reactivity with lymphatic filariasis

Norsyahida A, Riazi M, Sadjjadi SM, Muhammad Hafiznur Y, Low HC, Zeehaida M, et al.

Parasite Immunol., 2013 May-Jun;35(5-6):174-9.
PMID: 23448095 DOI: 10.1111/pim.12029

Enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of IgG, IgG4 and IgE antibodies against Strongyloides stercoralis. A commercial ELISA (IVD Research, USA) was also used, and the sensitivities and specificities of the four assays were determined. Serum samples from 26 patients with S. stercoralis infection and 55 patients with other infections or no infection were analysed. Sensitivities of the IgG4 , IgG, IgE and IgG (IVD) assays were 76.9%, 84.6%, 7.7% and 84.6%, respectively, while the specificities were 92.7%, 81.8%, 100% and 83.6%, respectively. If filariasis samples were excluded, the specificities of the IgG4 -ELISA and both IgG-ELISAs increased to 100% and 98%, respectively. A significant positive correlation was observed between IgG- and IgG4 -ELISAs (r = 0.4828; P = 0.0125). IgG- and IgG- (IVD) ELISAs (r = 0.309) were positively correlated, but was not significant (P = 0.124). Meanwhile there was no correlation between IgG4 - and IgG- (IVD) ELISAs (r = 0.0042; P = 0.8294). Sera from brugian filariasis patients showed weak, positive correlation between the titres of antifilarial IgG4 and the optical densities of anti-Strongyloides IgG4 -ELISA (r = 0.4544, P = 0.0294). In conclusion, the detection of both anti-Strongyloides IgG4 and IgG antibodies could improve the serodiagnosis of human strongyloidiasis. Furthermore, patients from lymphatic filariasis endemic areas who are serologically diagnosed with strongyloidiasis should also be tested for filariasis.
Multicentre evaluations of two new rapid IgG4 tests (WB rapid and panLF rapid) for detection of lymphatic filariasis

Noordin R, Itoh M, Kimura E, Abdul Rahman R, Ravindran B, Mahmud R, et al.

Filaria journal, 2007;6:9.
PMID: 17961262

In the global effort to eliminate lymphatic filariasis (LF), rapid field-applicable tests are useful tools that will allow on-site testing to be performed in remote places and the results to be obtained rapidly. Exclusive reliance on the few existing tests may jeopardize the progress of the LF elimination program, thus the introduction of other rapid tests would be useful to address this issue. Two new rapid immunochromatographic IgG4 cassette tests have been produced, namely WB rapid and panLF rapid, for detection of bancroftian filariasis and all three species of lymphatic filaria respectively. WB rapid was developed using BmSXP recombinant antigen, while PanLF rapid was developed using BmR1 and BmSXP recombinant antigens. A total of 165 WB rapid and 276 panLF rapid tests respectively were evaluated at USM and the rest were couriered to another university in Malaysia (98 WB rapid, 129 panLF rapid) and to universities in Indonesia (56 WB rapid, 62 panLF rapid), Japan (152 of each test) and India (18 of each test) where each of the tests underwent independent evaluations in a blinded manner. The average sensitivities of WB rapid and panLF rapid were found to be 97.6% (94%-100%) and 96.5% (94%-100%) respectively; while their average specificities were both 99.6% (99%-100%). Thus this study demonstrated that both the IgG4 rapid tests were highly sensitive and specific, and would be useful additional tests to facilitate the global drive to eliminate this disease.
Homologs of the Brugia malayi diagnostic antigen BmR1 are present in other filarial parasites but induce different humoral immune responses

Noordin R, Aziz RA, Ravindran B

Filaria journal, 2004 Dec 31;3(1):10.
PMID: 15627400

BACKGROUND: The recombinant antigen BmR1 has been extensively employed in both ELISA and immunochromatographic rapid dipstick (Brugia Rapid) formats for the specific and sensitive detection of IgG4 antibodies against the lymphatic filarial parasites Brugia malayi and Brugia timori. In sera of individuals infected with Wuchereria bancrofti the IgG4 reactivity to BmR1 is variable, and cross-reactivity of sera from individuals infected with Onchocerca volvulus or Loa loa was observed only in single cases. In order to characterize the homologs of the BmR1 antigen in W. bancrofti (Wb-BmR1), O. volvulus (Ov-BmR1) and L. loa (Ll-BmR1) the cDNA sequences were identified, the protein expressed and the antibody reactivity of patients' sera was studied. METHODS: PCR methodology was used to identify the cDNA sequences from cDNA libraries and/or genomic DNA of W. bancrofti, O. volvulus and L. loa. The clones obtained were sequenced and compared to the cDNA sequence of BmR1. Ov-BmR1 and Ll-BmR1 were expressed in E. coli and tested using an IgG4-ELISA with 262 serum samples from individuals with or without B. malayi, W. bancrofti, O. volvulus and L. loa infections or various other parasitic infections. BmR1, Ov-BmR1 and Ll-BmR1 were also tested for reactivity with the other three IgG subclasses in patients' sera. RESULTS: Wb-BmR1 was found to be identical to BmR1. Ov-BmR1 and Ll-BmR1 were found to be identical to each other and share 99.7% homology with BmR1. The pattern of IgG4 recognition of all serum samples to BmR1, Ov-BmR1 and Ll-BmR1 were identical. This included weak IgG4 reactivities demonstrated by L. loa- and O. volvulus-infected patients tested with Ov-BmR1 and Ll-BmR1 (or BmR1). With respect to reactivity to other IgG subclasses, sera from O. volvulus- and L. loa-infected patients showed positive reactions (when tested with BmR1, Ov-BmR1 or Ll-BmR1 antigens) only with IgG1. No reactivity was observed with IgG2 or with IgG3. Similarly, ELISAs to detect reactivity to other anti-filarial IgG subclasses antibodies showed that sera from individuals infected with B. malayi or W. bancrofti (active infections as well as patients with chronic disease) were positive with BmR1 only for IgG1 and were negative when tested with IgG2 and with IgG3 subclasses. CONCLUSIONS: This study demonstrates that homologs of the BmR1 antigen are present in W. bancrofti, O. volvulus and L. loa and that these antigens are highly conserved. Recognition of this antigen by patients' sera is similar with regard to IgG1, IgG2 and IgG3, but different for IgG4 antibodies. We conclude that the BmR1 antigen is suitable for detection of IgG4 antibodies in brugian filariasis. However, its homologs are not suitable for IgG4-based diagnosis of other filarial infections.
Comparison of IgG-ELISA and IgG4-ELISA for Toxocara serodiagnosis

Noordin R, Smith HV, Mohamad S, Maizels RM, Fong MY

Acta Trop, 2005 Jan;93(1):57-62.
PMID: 15589798

Diagnosis of human toxocariasis, caused by Toxocara canis or Toxocara cati, normally relies on a combination of the presence of clinical signs and symptoms backed by positive serology. The use of Toxocara excretory-secretory antigen (TES) in ELISA assays increases the test specificity. However, in tropical countries where soil-transmitted helminths are endemic, cross-reactivity from antibodies to these intestinal parasites poses a significant limitation for Toxocara serodiagnosis. To increase the specificity of serodiagnosis, we compared the use of IgG-ELISA to the use of IgG4-ELISA using commercially manufactured TES-coated plates. The sensitivity of the IgG-ELISA was 97.1%, while that of the IgG4-ELISA was 45.7%; the specificities were 36.0 and 78.6%, respectively. The study shows that employing both assays can improve the serodiagnosis of toxocariasis. An IgG4 immunoassay would also be useful in the secondary screening of antigen clones in the effort to develop improved serological tests for toxocariasis.
Comparison of IgG4 assays using whole parasite extract and BmR1 recombinant antigen in determining antibody prevalence in brugian filariasis

Noordin R, Wahyuni S, Mangali A, Huat LB, Yazdanbakhsh M, Sartono E

Filaria journal, 2004 Aug 12;3(1):8.
PMID: 15307892

BACKGROUND: Brugia malayi is endemic in several Asian countries with the highest prevalence in Indonesia. Determination of prevalence of lymphatic filariasis by serology has been performed by various investigators using different kinds of antigen (either soluble worm antigen preparations or recombinant antigens). This investigation compared the data obtained from IgG4 assays using two different kinds of antigen in a study on prevalence of antibodies to B. malayi. METHODS: Serum samples from a transmigrant population and life long residents previously tested with IgG4 assay using soluble worm antigen (SWA-ELISA), were retested with an IgG4 assay that employs BmR1 recombinant antigen (BmR1 dipstick [Brugia Rapid trade mark ]). The results obtained with the two antigens were compared, using Pearson chi-square and McNemar test. RESULTS: There were similarities and differences in the results obtained using the two kinds of antigen (SWA and BmR1). Similarities included the observation that assays using both antigens demonstrated an increasing prevalence of IgG4 antibodies in the transmigrant population with increasing exposure to the infection, and by six years living in the area, antibody prevalence was similar to that of life-long residents. With regards to differences, of significance is the demonstration of similar antibody prevalence in adults and children by BmR1 dipstick whereas by SWA-ELISA the antibody prevalence in adults was higher than in children. CONCLUSIONS: Results and conclusions made from investigations of prevalence of anti-filarial IgG4 antibody in a population would be affected by the assay employed in the study.
Fulltext Antibodies to somatic L3 antigen not protective against Brugia malayi infection

Noordin R, Abdullah KA, Azahri NA, Ramachandran CP

Southeast Asian J. Trop. Med. Public Health, 1999 Dec;30(4):678-81.
PMID: 10928359

Western blot analysis of infective larvae (L3) antigen of Brugia malayi were performed on 200 sera from six groups of individuals: 36 samples from B. malayi microfilaremic individuals; 10 samples from individuals with elephantiasis; 50 and 20 samples from amicrofilaremic individuals in a B. malayi endemic area with no anti-filarial IgG4 antibodies (towards microfilaria and adult worm antigens) and samples with high titres of the anti-filarial IgG4 antibodies respectively; 50 samples from non-endemic normals and 34 samples from geohelminth-infected individuals. After protein transfer, PVDF membrane strips were successively incubated with blocking solution, human sera, monoclonal anti-human IgG4 antibody-HRP and developed with luminol chemiluminescence substrate. 28/36 (78%), 1/10 (10%) and 16/20(80%) of sera from individuals with microfilariae, elephantiasis and amicrofilaremic individuals with high titers of anti-filarial IgG4 antibodies respectively recognized L3 antigenic epitopes; the dominant and consistent antigenic bands were of approximately MW 43 kDa, 14 kDa, 15 kDa and 59 kDa. The rest of the sera were unreactive. This study showed that microfilaremics may or may not mount a notable antibody response to somatic L3 antigens, thus lending evidence that antibody response to this antigen is not protective against establishment of Brugia malayi infection.
Comparison of two IgG4 assay formats (ELISA and rapid dipstick test) for detection of brugian filariasis

Noordin R, Shenoy RK, Rahman RA

Southeast Asian J. Trop. Med. Public Health, 2003 Dec;34(4):768-70.
PMID: 15115085

Brugia malayi infection is endemic in several Asian countries. Filaria-specific IgG4 antibody detection based on BmR1 recombinant antigen has been shown to be sensitive and specific for the diagnosis of brugian filariasis. Two formats of the test has been reported ie indirect ELISA (BE) and rapid dipstick test (BR). Since different test formats use different amounts of sample and reagents which may affect its sensitivity and specificity, this study was performed to compare these two test formats in the detection of B. malayi. A total of 264 blinded serum samples from India and Malaysia were employed. Group 1 comprised 164 samples from actively infected individuals and group 2 comprised 100 samples from filaria non-endemic areas. Sensitivity was 96.3% (158/164) and 90.8% (149/164) for rapid test and ELISA respectively; chi-square p=0.00. Both test formats demonstrated 100% specificity. Therefore the rapid test format was equally specific but more sensitive than the ELISA format. The ELISA format would be able to demonstrate decline in IgG4 titer post-treatment while the rapid test would be very useful for screening and diagnosis in the field.
Fulltext Evaluation of the Diagnostic Performance of Recombinant Antigen B1 for Detection of Cystic Echinococcosis Using Lateral Flow Dipstick Test

Noordin R, Khanbabaie S, Hafiznur Yunus M, Marti H, Nickel B, Fasihi Harandi M, et al.

Iran J Parasitol, 2020 10 22;15(3):290-298.
PMID: 33082792 DOI: 10.18502/ijpa.v15i3.4191

Background: Human echinococcosis is a neglected zoonotic disease distributed worldwide. It comprises cystic and alveolar forms, the former being the more prevalent disease. Imaging techniques are the first choice for diagnosis of cystic echinococcosis and serology is used as an additional diagnostic technique in doubtful cases or as the sole test in low-resource settings. Rapid diagnostic tests are useful and convenient for immunodiagnosis of cystic echinococcosis in endemic areas, where medical facilities often struggle with limited resources.
Methods: Recently, we have developed Hyd Rapid™, an IgG4 lateral flow dipstick test using recombinant antigen B1 for detection of cystic echinococcosis. This study was performed between 2016 until 2018 at the Institute for Research in Molecular Medicine, Universiti Sains Malaysia. The diagnostic performance of Hyd Rapid™ was tested in-house and at two international laboratories in Switzerland and Iran.
Results: The overall diagnostic sensitivity for detection of cystic and alveolar echinococcosis was 95% (56/59). Meanwhile, the diagnostic specificity, with and without exclusion of cysticercosis and fascioliasis, was 100% (n=48) and 88% (63/72), respectively.
Conclusion: Hyd Rapid™ detected cystic echinococcosis as well as probable cases of alveolar echinococcosis. Therefore, Hyd Rapid™ showed good potential as a serological tool for echinococcosis, and merits further evaluation.
Serodiagnostic methods for diagnosing larval toxocariasis

Noordin R, Yunus MH, Tan Farrizam SN, Arifin N

Adv Parasitol, 2020;109:131-152.
PMID: 32381194 DOI: 10.1016/bs.apar.2020.01.003

Toxocariasis is a human infection primarily caused by larvae of Toxocara canis from dogs, and also by T. cati from cats. Children have a more significant risk of acquiring the infection due to their closer contact with pets, and greater chances of ingesting soil. Diagnosis of toxocariasis is based on clinical, epidemiological, and serological data. Indirect IgG ELISA is a widely used serodiagnostic method for toxocariasis, with native T. canis TES most commonly used as the antigen. Western blots, using the same antigen, can be used to confirm positive ELISA findings to reduce false-positive results. Improvements in Toxocara serodiagnosis include the use of recombinant TES antigens, simpler and more rapid assay formats, and IgG4 subclass detection. Also, incorporation of recombinant T. cati TES protein increases the diagnostic sensitivity. Development of antigen detection tests using polyclonal and monoclonal antibodies, nanobodies, or aptamers can complement the antibody detection assays, and enhance the effectiveness of the serodiagnosis.
Fulltext Duration of detection of anti-BmR1 IgG4 antibodies after mass-drug administration (MDA) in Sarawak, Malaysia

Noordin R, Muhi J, Md Idris Z, Arifin N, Kiyu A

Trop Biomed, 2012 Mar;29(1):191-6.
PMID: 22543621 MyJurnal

The detection rates of brugian filariasis in three regions of Sarawak namely Central, North and South after three courses of mass drug administration (MDA) from year 2004 to 2006 was investigated. A recombinant BmR1 antigen-based IgG4 detection test, named Brugia Rapid and night blood smear for microfilaria (mf) detection were used. All three regions recorded a sharp fall in mf positive rates after a year post-MDA. Meanwhile Brugia Rapid positive rates declined more gradually to 3.8% and 5.6% of the pre-MDA levels in the Central and North regions, respectively. This study showed that in filariasis endemic areas in Sarawak, anti-filarial IgG4 antibodies to BmR1, as detected by the Brugia Rapid test, were positive for one to two years after mf disappearance.

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