Displaying publications 1 - 20 of 31 in total

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  1. Characterisation of the mitochondrial genome and phylogenetic analysis of Toxocara apodemi (Nematoda: Ascarididae)
    Gao Y, Hu Y, Xu S, Liang H, Lin H, Yin TH, et al.
    J Helminthol, 2024 Apr 15;98:e33.
    PMID: 38618902 DOI: 10.1017/S0022149X24000221
    We first sequenced and characterised the complete mitochondrial genome of Toxocara apodeme, then studied the evolutionary relationship of the species within Toxocaridae. The complete mitochondrial genome was amplified using PCR with 14 specific primers. The mitogenome length was 14303 bp in size, including 12 PCGs (encoding 3,423 amino acids), 22 tRNAs, 2 rRNAs, and 2 NCRs, with 68.38% A+T contents. The mt genomes of T. apodemi had relatively compact structures with 11 intergenic spacers and 5 overlaps. Comparative analyses of the nucleotide sequences of complete mt genomes showed that T. apodemi had higher identities with T. canis than other congeners. A sliding window analysis of 12 PCGs among 5 Toxocara species indicated that nad4 had the highest sequence divergence, and cox1 was the least variable gene. Relative synonymous codon usage showed that UUG, ACU, CCU, CGU, and UCU most frequently occurred in the complete genomes of T. apodemi. The Ka/Ks ratio showed that all Toxocara mt genes were subject to purification selection. The largest genetic distance between T. apodemi and the other 4 congeneric species was found in nad2, and the smallest was found in cox2. Phylogenetic analyses based on the concatenated amino acid sequences of 12 PCGs demonstrated that T. apodemi formed a distinct branch and was always a sister taxon to other congeneric species. The present study determined the complete mt genome sequences of T. apodemi, which provide novel genetic markers for further studies of the taxonomy, population genetics, and systematics of the Toxocaridae nematodes.
    Matched MeSH terms: Toxocara/genetics
  2. Seropositivity and risk factors of Toxocara canis infection in adult asthmatic patients
    Rouhani-Rankouhi SZ, Kow KS, Liam CK, Lau YL
    Trop Biomed, 2020 Sep 01;37(3):599-608.
    PMID: 33612775 DOI: 10.47665/tb.37.3.599
    This cross-sectional study involving 86 adult asthmatic patients aimed to determine the relationship between Toxocara seropositivity and severity of asthma in adult asthmatics and investigate the risk factors for Toxocara infection. In all cases, T. canis IgG level was measured using an anti-Toxocara IgG enzyme-linked immunosorbent assay kit. Total serum IgE and eosinophil count were also determined. The anti-Toxocara IgG seropositivity was 68.6% among asthmatic patients. There were no statistically significant associations between Toxocara seroprevalence and other risk factors, clinical symptoms of asthma and high level of total serum IgE and eosinophilia. Pet ownership could be an important risk factor for Toxocariasis. Having a pet at home and wheezing were significantly associated with Toxocara seropositivity in adult asthmatic patients.
    Matched MeSH terms: Toxocara
  3. 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.
    Matched MeSH terms: Toxocara/immunology
  4. Investigations for the Possible Use of a Monoclonal Antibody Produced against Strongyloides ratti Antigen as an Immunodiagnostic Reagent for Active Strongyloidiasis
    Mahmuda A, Bande F, Abdulhaleem N, Abd Majid R, Awang Hamat R, Omar Abdullah W, et al.
    Iran J Parasitol, 2018 8 3;13(2):204-214.
    PMID: 30069204
    Background: Currently, most of the available serological diagnostic kits for strongyloidiasis are based on the use of the crude antigens of Strongyloides ratti, which are good, but with less sensitivity towards the infection. Hence, this study aimed to produce and evaluate monoclonal antibody for detecting soluble parasite antigen in animal sera.

    Methods: The study was conducted in the Department of Medical Microbiology and Parasitology, University Putra Malaysia in 2014-2017. Saline extract protein from the infective larvae of S. ratti was used to immunize BALB/c mice and subsequent fusion of the B-cells with myeloma cells (SP2/0) using 50% PEG. The hybridomas were cultured in HAT medium and cloned by limiting dilutions. Positive hybrids were screened by indirect ELISA. The ascites fluid from the antibody-secreting hybridoma was purified and the MAb was characterized by western-blots and evaluated in sandwich ELISA for reactivity against the homologous and heterologous antigens.

    Results: An IgG1 that recognizes a 30 and 34 kDa protein bands was obtained. The MAb was recognized by all S. ratti-related antigens and cross-reacted with only Toxocara canis antigens in both assays. The minimum antigen detection limit was found to be 5 ng/ml. All antibody-positive rat and dog sera evaluated have shown antigen-positive reactions in Sandwich-ELISA.

    Conclusion: The MAb produced, was able to detect antigens in strongyloidiasis and toxocariasis in animal models and may also be useful for the serological detection of active strongyloidiasis and visceral toxocariasis in human sera.

    Matched MeSH terms: Toxocara canis
  5. Fulltext A Lateral Flow Rapid Test for Human Toxocariasis Developed Using Three Toxocara canis Recombinant Antigens
    Yunus MH, Tan Farrizam SN, Abdul Karim IZ, Noordin R
    Am J Trop Med Hyg, 2018 Jan;98(1):32-38.
    PMID: 29141740 DOI: 10.4269/ajtmh.17-0632
    Laboratory diagnosis of toxocariasis is still a challenge especially in developing endemic countries with polyparasitism. In this study, three Toxocara canis recombinant antigens, rTES-26, rTES-30, and rTES-120, were expressed and used to prepare lateral flow immunoglobulin G4 (IgG4) dipsticks. The concordance of the results of the rapid test (comprising three dipsticks) with a commercial IgG-enzyme-linked immunosorbent assay (ELISA) (Cypress Diagnostics, Belgium) was compared against the concordance of two other commercial IgG-ELISA kits (Bordier, Switzerland and NovaTec, Germany) with the Cypress kit. Using Toxocara-positive samples, the concordance of the dipstick dotted with rTES-26, rTES-30, and rTES-120 was 41.4% (12/29), 51.7% (15/29), and 72.4% (21/29), respectively. When positivity with any dipstick was considered as an overall positive rapid test result, the concordance with the Cypress kit was 93% (27/29). Meanwhile, when compared with the results of the Cypress kit, the concordance of IgG-ELISA from NovaTec and Bordier was 100% (29/29) and 89.7% (26/29), respectively. Specific IgG4 has been recognized as a marker of active infection for several helminthic diseases; therefore, the two non-concordant results of the rapid test when compared with the NovaTec IgG-ELISA kit may be from samples of people with non-active infection. All the three dipsticks showed 100% (50/50) concordance with the Cypress kit when tested with serum from individuals who were healthy and with other infections. In conclusion, the lateral flow rapid test is potentially a good, fast, and easy test for toxocariasis. Next, further validation studies and development of a test with the three antigens in one dipstick will be performed.
    Matched MeSH terms: Toxocara canis/immunology*
  6. Fulltext Seroprevalence of fascioliasis, toxocariasis, strongyloidiasis and cysticercosis in blood samples diagnosed in Medic Medical Center Laboratory, Ho Chi Minh City, Vietnam in 2012
    Nguyen T, Cheong FW, Liew JW, Lau YL
    Parasit Vectors, 2016 09 05;9(1):486.
    PMID: 27595647 DOI: 10.1186/s13071-016-1780-2
    BACKGROUND: Despite the global effort against neglected tropical diseases (NTDs), developing countries with middle to low income are still burdened by them. Vietnam has been undergoing substantial economic growth and urbanization, but underprivileged people living in rural and suburban areas are still having little access to public health infrastructure and proper sanitation. Hitherto, limited information is available for seroprevalence and risk factors of several parasitic diseases in Vietnam.

    METHODS: A retrospective study was performed on diagnostic results of Fasciola spp., Toxocara spp., Strongyloides stercoralis and Taenia solium IgG ELISA tests from Medic Medical Center Laboratory, Ho Chi Minh City in 2012. The data were first stratified before statistical analyses were performed. Seroprevalence of fascioliasis, toxocariasis, strongyloidiasis and cysticercosis was determined and the age and gender risk factors were evaluated.

    RESULTS: Seroprevalence of fascioliasis, toxocariasis, strongyloidiasis and cysticercosis was 5.9 % (590/10,084; 95 % CI: 5.44-6.36), 45.2 % (34,995/77,356; 95 % CI: 44.85-45.55), 7.4 % (3,174/42,920; 95 % CI: 7.15-7.65) and 4.9 % (713/14,601; 95 % CI: 4.55-5.25), respectively. Co-exposure to multiple parasites was detected in 890 males (45.7 %; 95 % CI: 43.49-47.91) and 1,059 females (54.3 %; 95 % CI: 52.09-56.51). Social structure and differences in behavioural factors caused the gender factor to have a significant effect on the prevalence of all the diseases, while the seropositivity for fascioliasis and strongyloidiasis were age group-related.

    CONCLUSIONS: The seroprevalence of fascioliasis, toxocariasis, strongyloidiasis and cysticercosis in the blood samples diagnosed in Medic Medical Center Laboratory, Ho Chi Minh City, in year 2012 were comparatively high. The Vietnamese customs and cultures, dietary habits and agricultural practices exposed them to high risk of contracting NTDs. Despite the possibility of false positive results due to antigenic cross-reactions, detection of IgG antibodies remains as a reliable method in sero-epidemiological study as it is non-invasive and demonstrates previous exposure of individuals to the parasites. Besides the implementation of strategies to control these diseases, epidemiological analysis and surveillance of diseases should also be continually strengthened to monitor the effectiveness of regimens and interventions.

    Matched MeSH terms: Toxocara/immunology
  7. Toxocara malaysiensis infection in domestic cats in Vietnam--An emerging zoonotic issue?
    Le TH, Anh NT, Nguyen KT, Nguyen NT, Thuy do TT, Gasser RB
    Infect Genet Evol, 2016 Jan;37:94-8.
    PMID: 26584512 DOI: 10.1016/j.meegid.2015.11.009
    Toxocara canis of canids is a parasitic nematode (ascaridoid) that infects humans and other hosts, causing different forms of toxocariasis. This species of Toxocara appears to be the most important cause of human disease, likely followed by Toxocara cati from felids. Although some studies from Malaysia and China have shown that cats can harbor another congener, T. malaysiensis, no information is available about this parasite for other countries. Moreover, the zoonotic potential of this parasite is unknown at this point. In the present study, we conducted the first investigation of domestic dogs and cats for Toxocara in Vietnam using molecular tools. Toxocara malaysiensis was identified as a common ascaridoid of domestic cats (in the absence of T. cati), and T. canis was commonly found in dogs. Together with findings from previous studies, the present results emphasize the need to explore the significance and zoonotic potential of T. malaysiensis in Vietnam and other countries where this parasite is endemic and prevalent in cats.
    Matched MeSH terms: Toxocara/classification*; Toxocara/genetics; Toxocara/isolation & purification*
  8. Production of Toxocara cati TES-120 Recombinant Antigen and Comparison with its T. canis Homolog for Serodiagnosis of Toxocariasis
    Zahabiun F, Sadjjadi SM, Yunus MH, Rahumatullah A, Moghaddam MH, Saidin S, et al.
    Am J Trop Med Hyg, 2015 Aug;93(2):319-25.
    PMID: 26033026 DOI: 10.4269/ajtmh.15-0190
    Toxocariasis is a cosmopolitan zoonotic disease caused by the infective larvae of Toxocara canis and T. cati. Diagnosis in humans is usually based on clinical symptoms and serology. Immunoglobulin G (IgG)-enzyme-linked immunosorbent assay kits using T. canis excretory-secretory (TES) larval antigens are commonly used for serodiagnosis. Differences in the antigens of the two Toxocara species may influence the diagnostic sensitivity of the test. In this study, T. cati recombinant TES-120 (rTES-120) was cloned, expressed, and compared with its T. canis homolog in an IgG4-western blot. The diagnostic sensitivity and specificity of T. cati rTES-120 were 70% (33/47) and 100% (39/39), respectively. T. canis rTES-120 showed 57.4% sensitivity and 94.4% specificity. When the results of assays using rTES-120 of both species were considered, the diagnostic sensitivity was 76%. This study shows that using antigens from both Toxocara species may improve the serodiagnosis of toxocariasis.
    Matched MeSH terms: Toxocara canis/isolation & purification*
  9. Fulltext Field evaluation of a rapid diagnostic test to detect antibodies in human toxocariasis
    Lim PK, Yamasaki H, Mak JW, Wong SF, Chong CW, Yap IK, et al.
    Acta Trop, 2015 Aug;148:32-7.
    PMID: 25910623 DOI: 10.1016/j.actatropica.2015.04.011
    Human toxocariasis which is caused mainly by the larvae of Toxocara canis and Toxocara cati, is a worldwide zoonotic disease that can be a potentially serious human infection. The enzyme-linked immunosorbent assay (ELISA) using T. canis excretory-secretory (TES) antigens harvested from T. canis larvae is currently the serological test for confirming toxocariasis. An alternative to producing large amounts of Toxocara TES and improved diagnosis for toxocariasis is through the development of highly specific recombinant antigens such as the T. canis second stage larva excretory-secretory 30 kDa protein (recTES-30). The aim of this study was to evaluate the sensitivity and specificity of a rapid diagnostic kit (RDT, named as iToxocara kit) in comparison to recTES-30 ELISA in Serendah Orang Asli village in Selangor, Malaysia. A total of 133 subjects were included in the study. The overall prevalence rates by ELISA and RDT were 29.3% and 33.1%, respectively, with more positive cases detected in males than females. However, no association was found between toxocariasis and gender or age. The percentage sensitivity, specificity, positive predictive value and negative predictive value of RDT were 85.7%, 90.1%, 80% and 93.2%, respectively. The prevalence for toxocariasis in this population using both ELISA and RDT was 27.1% (36/133) and the K-concordance test suggested good agreement of the two tests with a Cohen's kappa of 0.722, P<0.01. In addition, the followed-up Spearman rank correlation showed a moderately high correlation at R=0.704 and P<0.01. In conclusion, the RDT kit was faster and easier to use than an ELISA and is useful for the laboratory diagnosis of hospitalized cases of toxocariasis.
    Matched MeSH terms: Toxocara canis/immunology; Toxocara canis/isolation & purification*
  10. Fulltext The role of worm infestation in allergic rhinitis
    Manuel AM, Kuljit S, Gopalakrishnan G, Suresh KG, Balraj P
    Trop Biomed, 2012 Sep;29(3):360-5.
    PMID: 23018498 MyJurnal
    The purpose of this study is to determine the relevance of the hygiene hypothesis; that is to determine if worm infestation has a protective role against the development of allergic rhinitis. A prospective case controlled study was conducted. Specific IgG levels to Toxocara were studied in 85 patients confirmed to have allergic rhinitis and were compared to levels in another 85 controls, with no form of allergy. The IgG assay was done using ELISA technique. There was a higher incidence of positive specific IgG to Toxocara in the controls as compared to allergic patients. The values were statistically significant [Chi square test (p=0.002)]. This negative association between worm infestation and allergic rhinitis suggests that a previous worm infestation could protect against the development of allergic rhinitis.
    Matched MeSH terms: Toxocara canis/immunology*
  11. Fulltext Diffuse unilateral subacute neuroretinitis in a young boy: a case report
    Guan-Fook N, Hayati AA, Raja-Azmi MN, Liza-Sharmini AT, Wan-Hazabbah WH, Zunaina E
    Clin Ophthalmol, 2012;6:487-90.
    PMID: 22536041 DOI: 10.2147/OPTH.S29806
    We report a case of diffuse unilateral subacute neuroretinitis in a young boy with no clinical visualization of nematode. The diagnosis was made based on clinical findings and detection of Toxocara immunoglobulin G by Western blot test. An 11-year-old Malay boy presented with progressive blurring of vision in the left eye for a duration of 1 year. It was associated with intermittent floaters. Visual acuity in the left eye was 6/45 and improved to 6/24 with pinhole. There was positive relative afferent pupillary defect, impaired color vision, and presence of red desaturation in the left eye. There were occasional cells in the anterior chamber with no conjunctiva injection. Posterior segment examination revealed mild-to-moderate vitritis and generalized pigmentary changes of the retina with attenuated vessels. The optic disk was slightly hyperemic with mild edema. There was presence of multiple, focal, gray-white subretinal lesions at the inferior part of the retina. Full blood picture results showed eosinophilia with detection of Toxocara immunoglobulin G by Western blot test. Investigations for other infective causes and connective tissue diseases were negative. The diagnosis of diffuse unilateral subacute neuroretinitis secondary to Toxocara was made based on clinical findings and laboratory results. He was treated with oral albendazole 400 mg daily for 5 days and oral prednisolone 1 mg/kg with tapering doses over 6 weeks. At 1 month follow-up, the inflammation had reduced, and multiple, focal, gray-white subretinal lesions were resolved; however there was no improvement of vision.
    Matched MeSH terms: Toxocara
  12. Fulltext A case report of ocular toxocariasis
    Azira NM, Zeehaida M
    Asian Pac J Trop Biomed, 2011 Apr;1(2):164-5.
    PMID: 23569750 DOI: 10.1016/S2221-1691(11)60018-X
    Ocular toxocariasis is prevalent among children. The symptoms and signs may mimic other ocular pathologies such as malignancies and other infectious diseases (such as toxoplasmosis and syphilis). We presented a case of progressive blurring of vision in a single eye of a 9-year-old boy. The presence of anti-toxocara antibody in serum samples helps to confirmation the diagnosis in our patient. Despite of treatment, the boy had lost his vision on the affected eye.
    Matched MeSH terms: Toxocara canis/immunology; Toxocara canis/isolation & purification*
  13. Fulltext Seroprevalence of toxocariasis among Orang Asli (Indigenous people) in Malaysia using two immunoassays
    Romano N, Nor Azah MO, Rahmah N, Lim Y AL, Rohela M
    Trop Biomed, 2010 Dec;27(3):585-94.
    PMID: 21399601 MyJurnal
    Toxocariasis is a zoonotic helminthic infection of humans caused by the dog roundworm (Toxocara canis) or cat roundworm (Toxocara cati). There are two main human syndromes: visceral larva migrans (VLM), which are characterized by symptoms associated with major organs and ocular larva migrans (OLM), in which pathological effects on the host are restricted to the eye and the optic nerve. The present study evaluated the seroprevalence of toxocariasis among the Orang Asli with an IgG4-ELISA using recombinant antigens (rTES-26, rTES-30 and rTES-120) and an IgG-ELISA commercial kit (Cypress Diagnostic, Belgium). A total of 188 serum samples were analyzed using IgG4-ELISA recombinant antigens while 83 were tested using IgG-ELISA. Overall, 9 out of 188 (4.8%) samples were positive with the former assay: rTES-26 (2.7%) and rTES-30 (2.1%); and 63 out of 83 (75.9%) were positive with the IgG-ELISA. In general, the seroprevalence of toxocariasis among males (9.5%) was higher compared to females (1%). Children below 12 years (6.3%) have higher seroprevalence rate compared to adults (1.2%). Out of 59 IgG positive samples, 56 (94.9%) were also positive with soil-transmitted helminth (STH) infections which may indicate high false positivity. None of the IgG4- ELISA positive samples were positive with STH infections. Of 9 positive samples with IgG4-ELISA, 7 were also positive with IgG-ELISA giving the probability of true cases. The present finding indicated that exposure to Toxocara infection is not unusual among Malaysian aborigines, and it affects both sexes and all age groups. As a prevention strategy, more effective public health programmes to promote better understanding on the consequences of toxocariasis among the Orang Asli communities are deemed necessary.
    Matched MeSH terms: Toxocara/immunology*
  14. Fulltext Development and evaluation of a sensitive and specific assay for diagnosis of human toxocariasis by use of three recombinant antigens (TES-26, TES-30USM, and TES-120)
    Mohamad S, Azmi NC, Noordin R
    J Clin Microbiol, 2009 Jun;47(6):1712-7.
    PMID: 19369434 DOI: 10.1128/JCM.00001-09
    Diagnosis of human toxocariasis currently relies on serologic tests that use Toxocara excretory-secretory (TES) antigen to detect immunoglobulin G (IgG) antibodies to the larvae. In general, however, these assays do not have adequate specificity for use in countries in which other soil-transmitted helminths are endemic. The use of recombinant antigens in these assays, however, is promising for improving the specificity of the diagnosis of toxocariasis. Toward this goal, we developed an IgG4 enzyme-linked immunosorbent assay (ELISA) involving three recombinant antigens: rTES-30USM (previously produced), rTES-26, and rTES-120. The latter two antigens were produced by reverse transcription-PCR cloning; subcloned into glutathione S-transferase (GST)-tagged and His-tagged prokaryotic expression vectors, respectively; and expressed in Escherichia coli. The recombinant proteins were subsequently purified by affinity chromatography using GST and His-Trap resins. The diagnostic potential of each purified recombinant antigen was tested with various immunoglobulin classes (IgG, IgM, and IgE) and IgG subclasses. The IgG4 ELISA was determined to have the highest specificity and was further evaluated using a panel of serum samples. The rTES-26 IgG4 ELISA showed 80.0% (24/30 samples positive) sensitivity, and both the rTES-30USM IgG4 ELISA and rTES-120 IgG4 ELISA had 93.0% (28/30) sensitivity. Combined use of rTES-120 and rTES-30 IgG4 ELISA for the diagnosis of toxocariasis provided 100% sensitivity. The specificities of rTES-26, rTES-30USM, and rTES-120 antigens were 96.2%, 93.9%, and 92.0%, respectively. These results indicate that the development of a diagnostic test using the three recombinant antigens will allow for more-accurate detection of toxocariasis.
    Matched MeSH terms: Toxocara/immunology*
  15. rTES-30USM: cloning via assembly PCR, expression, and evaluation of usefulness in the detection of toxocariasis
    Norhaida A, Suharni M, Liza Sharmini AT, Tuda J, Rahmah N
    Ann Trop Med Parasitol, 2008 Mar;102(2):151-60.
    PMID: 18318937 DOI: 10.1179/136485908X252250
    Currently, the laboratory diagnosis of toxocariasis, caused by Toxocara canis or T. cati, mainly relies on serological tests. Unfortunately, however, the specificities of most of the commercial tests that are available for the serodiagnosis of this disease are not very high and this may cause problems, especially in tropical countries where co-infections with other helminths are common. In an effort to develop a serological assay with improved specificity for the detection of Toxocara infection, an IgG(4)-ELISA based on a recombinant version (rTES-30USM) of the 30-kDa Toxocara excretory-secretory antigen (TES-30) has recently been developed. To produce the antigen, the TES-30 gene was cloned via assembly PCR, subcloned into a His-tagged prokaryotic expression vector, and purified by affinity chromatography using Ni(2+)-nitrilotriacetic-acid (Ni-NTA) resin. The performance of the ELISA based on the recombinant antigen was then compared with that of commercial kit, based on an IgG-ELISA, for the serodiagnosis of toxocariasis (Toxocara IgG-ELISA; Cypress Diagnostics, Langdorp, Belgium). Both assays were used to test 338 serum samples, including 26 samples from probable cases of toxocariasis. Assuming that all the probable cases were true cases, the assay based on rTES-30USM demonstrated a sensitivity of 92.3% (24/26) and a specificity of 89.6% (103/115) whereas the commercial kit exhibited a sensitivity of 100% (26/26) but a specificity of only 55.7% (64/115). The high sensitivity and specificity exhibited by the new IgG(4)-ELISA should make the assay a good choice for use in tropical countries and any other area where potentially cross-reactive helminthic infections are common.
    Matched MeSH terms: Toxocara canis*
  16. Transvitreal migration of a Toxocara larva resulting in a second chorioretinal granuloma
    Sivaratnam D, Subrayan V, Ali NA
    Jpn. J. Ophthalmol., 2008 Sep-Oct;52(5):416-417.
    PMID: 18991049 DOI: 10.1007/s10384-008-0569-z
    Matched MeSH terms: Toxocara canis/immunology; Toxocara canis/isolation & purification*
  17. PCR tools for the verification of the specific identity of ascaridoid nematodes from dogs and cats
    Li MW, Lin RQ, Chen HH, Sani RA, Song HQ, Zhu XQ
    Mol Cell Probes, 2007 Oct-Dec;21(5-6):349-54.
    PMID: 17532185
    Based on the sequences of the internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA (rDNA) of Toxocara canis, Toxocara cati, Toxocara malaysiensis and Toxascaris leonina, specific forward primers were designed in the ITS-1 or ITS-2 for each of the four ascaridoid species of dogs and cats. These primers were used individually together with a conserved primer in the large subunit of rDNA to amplify partial ITS-1 and/or ITS-2 of rDNA from 107 DNA samples from ascaridoids from dogs and cats in China, Australia, Malaysia, England and the Netherlands. This approach allowed their specific identification, with no amplicons being amplified from heterogeneous DNA samples, and sequencing confirmed the identity of the sequences amplified. The minimum amounts of DNA detectable using the PCR assays were 0.13-0.54ng. These PCR assays should provide useful tools for the diagnosis and molecular epidemiological investigations of toxocariasis in humans and animals.
    Matched MeSH terms: Toxocara/genetics*; Toxocara/isolation & purification*
  18. The occurrence of Toxocara malaysiensis in cats in China, confirmed by sequence-based analyses of ribosomal DNA
    Li MW, Zhu XQ, Gasser RB, Lin RQ, Sani RA, Lun ZR, et al.
    Parasitol Res, 2006 Oct;99(5):554-7.
    PMID: 16636846
    Non-isotopic polymerase chain reaction (PCR)-based single-strand conformation polymorphism and sequence analyses of the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA (rDNA) were utilized to genetically characterise ascaridoids from dogs and cats from China by comparison with those from other countries. The study showed that Toxocara canis, Toxocara cati, and Toxascaris leonina from China were genetically the same as those from other geographical origins. Specimens from cats from Guangzhou, China, which were morphologically consistent with Toxocara malaysiensis, were the same genetically as those from Malaysia, with the exception of a polymorphism in the ITS-2 but no unequivocal sequence difference. This is the first report of T. malaysiensis in cats outside of Malaysia (from where it was originally described), supporting the proposal that this species has a broader geographical distribution. The molecular approach employed provides a powerful tool for elucidating the biology, epidemiology, and zoonotic significance of T. malaysiensis.
    Matched MeSH terms: Toxocara/genetics*; Toxocara canis/genetics; Toxocara canis/parasitology
  19. 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.
    Matched MeSH terms: Toxocara/isolation & purification*
  20. Recombinant expression of the larval excretory-secretory antigen TES-120 of Toxocara canis in the methylotrophic yeast Pichia pastoris
    Fong MY, Lau YL
    Parasitol Res, 2004 Jan;92(2):173-6.
    PMID: 14655048
    A gene encoding the larval excretory-secretory antigen TES-120 of the dog ascarid worm Toxocara canis was cloned into the methylotrophic yeast Pichia pastoris. Specificity of the recombinant TES-120 antigen produced by the yeast was investigated. Forty-five human serum samples from patients infected with different()parasitic organisms, including 8 cases of toxocariasis, were tested against the recombinant antigen in immunoblot assays. Results from the assays showed that the recombinant TES-120 antigen reacted with sera from toxocariasis patients only. This highly specific recombinant TES-120 antigen can potentially be used for the development of an inexpensive serodiagnostic assay for human toxocariasis.
    Matched MeSH terms: Toxocara canis/genetics; Toxocara canis/growth & development; Toxocara canis/immunology*; Toxocara canis/metabolism
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