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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*
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
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 canis/genetics; Toxocara canis/parasitology
Prevalence of Toxocara canis antibody among children with bronchial asthma in Klang Hospital, Malaysia

Hakim SL, Thadasavanth M, Shamilah RH, Yogeswari S

Trans R Soc Trop Med Hyg, 1998 2 17;91(5):528.
PMID: 9463657 DOI: 10.1016/s0035-9203(97)90010-9
Matched MeSH terms: Toxocara canis*
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*
Recombinant expression of Toxocara canis excretory-secretory antigen TES-120 in Escherichia coli

Fong MY, Lau YL, Init I, Jamaiah I, Anuar AK, Rahmah N

Southeast Asian J Trop Med Public Health, 2003 Dec;34(4):723-6.
PMID: 15115078

The gene encoding the excretory-secretory antigen TES-120 of dog ascarid worm Toxocara canis was cloned into the bacterium Escherichia coli. The specificity of the recombinant TES-120 antigen produced by the bacterium was investigated. A total of 45 human serum samples from patients infected with differenthelminthes and protozoa, including 8 cases of toxocariasis, were tested against the recombinant antigens in immunoblot assays. The results from the assays revealed 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/immunology*
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*
Fulltext ELISA seropositivity for Toxocara canis antibodies in Malaysia, 1989-1991

Hakim SL, Mak JW, Lam PL

Med J Malaysia, 1993 Sep;48(3):303-7.
PMID: 8183143

The laboratory test results for visceral larva migrans (VLM) using ELISA for Toxocara canis antibodies employed by the Institute for Medical Research, Kuala Lumpur, is described. A total of 331 serum samples received from hospitals and general practitioners all over Malaysia were tested. The test utilises excretory-secretory antigens obtained from in vitro culture of second stage T. canis larvae. The overall seropositivity rate was 19.6%, the highest positive rate being in Indians (35.5%), followed by the Malays (14.8%), Chinese (10.9%) and others (29.4%). Seropositivity rate was highest in children below the age of 10; 89% of patients presented with eosinophilia and 93% with VLM syndrome were children.

Matched MeSH terms: Toxocara canis/immunology*
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*
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*
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*
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*
Fulltext Seroprevalence of Toxocara canis antibodies among Orang Asli (aborigines) in Peninsular Malaysia

Hakim SL, Mak JW, Lam PL, Nazma S, Normaznah Y

Southeast Asian J Trop Med Public Health, 1992 Sep;23(3):493-6.
PMID: 1488706

An enzyme-linked immunosorbent assay using excretory-secretory antigens of the second stage larvae maintained in vitro was used to determine the seroprevalence of Toxocara antibodies in Orang Asli (aborigines) of Peninsular Malaysia. The mean + 3 SD optical density of 30 healthy subjects was used as the cut-off point. Overall prevalence was found to be 31.9%. No significant relationship was found between positive rates with sex and age groups, though children between 0 to 9 years recorded the highest positive rates. Eosinophil counts were found to be closely related to the proportion of positivity to toxocaral infection and mean optical densities. There was some degree of cross-reaction with Trichuris trichuria positive sera.

Matched MeSH terms: Toxocara canis/immunology*
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

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