Excretory-secretory products of Toxocara canis larvae have been considered as a major functional antigen in immune responses against toxocariasis. We studied ultrastructural localization of T. canis second-stage larval antigen using a seropositive human serum under immunogold electron microscopy. High-density gold particles were observed in the secretory cells, excretory duct, intestinal epithelium, and cuticle of the larval worm sections. The distribution of the positive reactions in the larval worms suggests that the nature of the antigen is excretory-secretory antigen including waste metabolites and secretory enzymes.
Animals ; Antigens, Helminth/*immunology/ultrastructure ; Humans ; Larva/*immunology/ultrastructure ; Toxocara canis/*immunology/ultrastructure ; Toxocariasis/*immunology

The intradermal studies with the fraction of Ascaris lumbricoides and Toxocara canis were performed to human and dog, and the following results were observed. Wheal and erythema were appeared in the cases of ascaris infection or who had past history, but not in the ascaris free before. The size of wheal reached to peak 30 minutes after the injection. The crude antigen had specificity and showed no cross reaction. The crude antigen cause the strongest and largest reaction than the other substances; protein, polysaccharide and the mixed antigen. No cutaneous reaction was observed with the fraction of polysaccharides. The size of wheal did not parallel with the worm burden. The skin reaction was appeared four weeks after the infection.
parasitology-nematode-Ascaris lumbricoides ; Toxocara canis ; immunology-crude antigen-skin test ; dog ; protein ; polysaccharide ; antigen

This study was performed to investigate whethere there is cross-reactivity between Dirofilaria immitis and three intestinal nematodes of dogs. In ELISA, D. immitis-infected dog sera obtained at the 4th molting stage (9-11 weeks) and microfilaremic stage (25-30 weeks) were shown to be highly reactive with crude extract of T. canis. In immunoblotting, some antigenic fractions, 44, 57, 88, 100 kDa of crude extract of T. canis, were found to be positive reaction with sera of dogs infected with D. immitis. However, little or no cross-reaction were observed between sera of D. immitis-infected dogs and crude extract antigen of T. vulpis or A. caninum. These result suggest that there are partial cross reaction between sera of D. immitis-infected dogs and the antigen of T. canis.
Animals ; Antibodies, Helminth/*immunology ; Antigens, Helminth/*immunology ; Cross Reactions ; Dirofilaria immitis/*immunology ; Dirofilariasis/*immunology ; Dogs ; Enzyme-Linked Immunosorbent Assay ; Immunoblotting ; Toxocara canis/*immunology

Toxocariasis is a soil-transmitted helminthozoonosis due to infection of humans by larvae of Toxocara canis. The disease could produce cognitive and behavioral disturbances especially in children. Meanwhile, in our modern era, the incidence of immunosuppression has been progressively increasing due to increased incidence of malignancy as well as increased use of immunosuppressive agents. The present study aimed at comparing some of the pathological and immunological alterations in the brain of normal and immunosuppressed mice experimentally infected with T. canis. Therefore, 180 Swiss albino mice were divided into 4 groups including normal (control) group, immunocompetent T. canis-infected group, immunosuppressed group (control), and immunosuppressed infected group. Infected mice were subjected to larval counts in the brain, and the brains from all mice were assessed for histopathological changes, astrogliosis, and IL-5 mRNA expression levels in brain tissues. The results showed that under immunosuppression, there were significant increase in brain larval counts, significant enhancement of reactive gliosis, and significant reduction in IL-5 mRNA expression. All these changes were maximal in the chronic stage of infection. In conclusion, the immunopathological alterations in the brains of infected animals were progressive over time, and were exaggerated under the effect of immunosuppression as did the intensity of cerebral infection.
Animals ; Brain/*pathology ; Disease Models, Animal ; Female ; Gene Expression Profiling ; Histocytochemistry ; *Immunocompromised Host ; Immunohistochemistry ; Interleukin-5/genetics ; Male ; Mice ; Parasite Load ; Toxocara canis/*immunology ; Toxocariasis/*immunology/*pathology

Toxocariasis is a soil-transmitted helminthozoonosis due to infection of humans by larvae of Toxocara canis. The disease could produce cognitive and behavioral disturbances especially in children. Meanwhile, in our modern era, the incidence of immunosuppression has been progressively increasing due to increased incidence of malignancy as well as increased use of immunosuppressive agents. The present study aimed at comparing some of the pathological and immunological alterations in the brain of normal and immunosuppressed mice experimentally infected with T. canis. Therefore, 180 Swiss albino mice were divided into 4 groups including normal (control) group, immunocompetent T. canis-infected group, immunosuppressed group (control), and immunosuppressed infected group. Infected mice were subjected to larval counts in the brain, and the brains from all mice were assessed for histopathological changes, astrogliosis, and IL-5 mRNA expression levels in brain tissues. The results showed that under immunosuppression, there were significant increase in brain larval counts, significant enhancement of reactive gliosis, and significant reduction in IL-5 mRNA expression. All these changes were maximal in the chronic stage of infection. In conclusion, the immunopathological alterations in the brains of infected animals were progressive over time, and were exaggerated under the effect of immunosuppression as did the intensity of cerebral infection.
Animals ; Brain/*pathology ; Disease Models, Animal ; Female ; Gene Expression Profiling ; Histocytochemistry ; *Immunocompromised Host ; Immunohistochemistry ; Interleukin-5/genetics ; Male ; Mice ; Parasite Load ; Toxocara canis/*immunology ; Toxocariasis/*immunology/*pathology

Roundworms of Toxocara canis and Toxascaris leonina are common gastrointestinal helminths of canids over the world. Humans are infected with T. canis larvae through ingestion of infective eggs in contaminated environments or larvae by consumption of raw or uncooked meat or livers. Recently, patients of clinically diagnosed toxocariasis are increasing and require correct diagnosis in Korea. The present study investigated serological cross-reactivity between crude antigens of T. canis (TCLA) and T. leonina (TLLA) larvae. We collected serum specimens from 177 toxocariasis patients who were clinically suspected in the Seoul National University Hospital and 115 healthy controls. An ELISA method for toxocariasis was used to evaluate diagnostic efficacy of TLLA for serodiagnosis of human toxocariasis. The IgG ELISA using TLLA gave 14 (14.3%) positives of 98 TCLA positive specimens among 177 suspected toxocariasis patients. Most of them showed high absorbances with TCLA. In conclusion, there is a partial cross reaction between serum specimens of toxocariasis and TLLA.
Animals ; Antibodies, Helminth/blood ; Antigens, Helminth/*immunology ; Cross Reactions ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunoglobulin G/blood ; Larva/immunology/metabolism ; Toxascaris/growth & development/*immunology/isolation & purification ; Toxocara canis/growth & development/*immunology/isolation & purification ; Toxocariasis/*diagnosis/parasitology

Toxocariasis is a worldwide zoonosis caused by larvae of ascarid nematodes of dogs or cats, Toxocara canis or T. cati. Diagnosis of human toxocariasis currently relies on serology that uses T. canis excretory-secretory antigen to detect specific IgG antibodies by ELISA. We investigated the serodiagnostic efficacy of ELISA using crude antigen of T. canis larvae (TCLA). Serum specimens of 64 clinically confirmed toxocariasis, 115 healthy controls, and 119 other tissue-invading helminthiases were screened by ELISA using TCLA. The ELISA using TCLA showed 92.2% (59/64 patient samples) sensitivity and 86.6% (103/119) specificity. Its positive diagnostic predictivity was 78.7% and negative predictivity was 97.8%. No serum of healthy controls reacted but that of anisakiasis (45.5%), gnathostomiasis (19.2%), clonorchiasis (15.8%), sparganosis (11.1%), and cysticercosis (6.3%) cross-reacted. Immunoblot analysis on TCLA recognized antigenic proteins of 28- and 30-kDa bands in their dominant protein quantity and strong blotting reactivity. The present results indicate that the ELISA using our TCLA antigen is acceptable by the sensitivity and specificity for serodiagnosis of human toxocariasis. ELISA with TCLA is recommended to make differential diagnosis for patients with any sign of organ infiltration and eosinophilia.
Adolescent ; Adult ; Aged ; Animals ; Antigens, Helminth/chemistry/*diagnostic use/immunology/isolation & purification ; Cats ; Dogs ; Enzyme-Linked Immunosorbent Assay/*methods ; Female ; Humans ; Larva/chemistry/immunology ; Male ; Middle Aged ; Serologic Tests ; Toxocara canis/chemistry/*immunology ; Toxocariasis/*diagnosis/immunology/parasitology ; Young Adult

Recently reports on toxocariasis are increasing by serodiagnosis in Korea. A previously healthy 17-yr-old boy complained of headache, fever, dyspnea, and anorexia. He showed symptoms and signs of eosinophilic meningitis with involvement of the lungs and liver. Specific IgG antibody to Toxocara canis larval antigen was positive in serum and cerebrospinal fluid by ELISA. He took raw ostrich liver with his parents 4 weeks before the symptom onset. His parents were seropositive for T. canis antigen but had no symptoms or signs suggesting toxocariasis. This is the first report of toxocariasis in a family due to ingestion of raw ostrich liver in Korea.
Adolescent ; Animals ; Antibodies, Helminth/blood/cerebrospinal fluid ; Eating ; Humans ; Larva/immunology ; Liver/parasitology ; Male ; Meningitis/*diagnosis/parasitology ; Struthioniformes ; Tomography, X-Ray Computed ; Toxocara canis/growth & development/*immunology/isolation & purification ; Toxocariasis/*diagnosis/parasitology/transmission

PURPOSE: Since few reports had been published on the prevalence of toxocariasis in ankylosing spondylitis (AS) patients with acute non-granulomatous anterior uveitis (ANGAU), the aim of this work was to determine the presence of antibodies against Toxocara canis in AS patients with ANGAU. METHODS: Thirty-six patients (14 female and 22 male) with AS were enrolled in the study. The history of ANGAU was accepted only if diagnosed by an ophthalmologist. The detection of IgG antibodies to T. canis was determined by enzyme-linked immunosorbent assay. In addition, antibodies to Ascaris lumbricoides were also tested to verify non-specific reactions. RESULTS: The prevalence of ANGAU in the AS patients was 58% (21 / 36), and 38% (8 / 21) of the patients with ANGAU were positive for antibodies to Toxocara, while 7% (1 / 15) of AS patients without ANGAU were positive for T. canis (p = 0.038, two tails; mid-p exact). No antibodies were detected to A. lumbricoides antigens in the serum samples of patients with AS. CONCLUSIONS: These data suggest that the seroprevalence of antibodies to T. canis is high in Mexican patients with AS-associated uveitis, suggesting a chronic asymptomatic toxocariosis, which could be associated with the pathogenesis of ANGAU; however, further larger-scale studies are needed to confirm this observation.
Acute Disease ; Adult ; Aged ; Animals ; Antibodies, Anti-Idiotypic/*isolation & purification ; Enzyme-Linked Immunosorbent Assay ; Eye Infections, Parasitic/complications/*immunology/parasitology ; Female ; Humans ; Immunoglobulin G/*immunology ; Male ; Middle Aged ; Seroepidemiologic Studies ; Spondylitis, Ankylosing/*complications/immunology/parasitology ; Toxocara canis/*immunology/isolation & purification ; Toxocariasis/complications/*immunology/parasitology ; Uveitis, Anterior/complications/*immunology/parasitology ; Young Adult

PURPOSE: This study evaluated the prevalence of ocular toxocariasis (OT) in patients with uveitis of unknown etiology who visited a tertiary hospital in South Korea and assessed the success of serum anti-Toxocara immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) as a diagnostic test for OT. METHODS: The records of consecutive patients with intraocular inflammation of unknown etiology were reviewed. All participants underwent clinical and laboratory investigations, including ELISA for serum anti-Toxocara IgG. OT was diagnosed based on typical clinical findings. Clinical characteristics, seropositivity, and IgG titers were compared between patients diagnosed with OT and non-OT uveitis. The seropositivity and the diagnostic value of anti-Toxocara IgG was investigated among patients with different types of uveitis. RESULTS: Of 238 patients with uveitis of unknown etiology, 71 (29.8%) were diagnosed with OT, and 80 (33.6%) had positive ELISA results for serum anti-Toxocara IgG. The sensitivity and specificity of the ELISA test were 91.5% (65 / 71) and 91.0% (152 / 167), respectively. The positive predictive value of the serum anti-Toxocara IgG assay was 81.3%. Among patients with anterior, intermediate, posterior, and panuveitis, the prevalence rates of OT were 8.3%, 47.1%, 44.8%, and 7.1%, respectively; the seropositivity percentages were 18.1%, 47.1%, 43.7%, and 17.9%; and the positive predictive values were 38.5%, 95.8%, 92.1%, and 40.0%. The serum anti-Toxocara IgG titer also significantly decreased following albendazole treatment. CONCLUSIONS: OT is a common cause of intraocular inflammation in the tertiary hospital setting. Considering that OT is more prevalent in intermediate and posterior uveitis, and that the positive predictive value of the anti-Toxocara IgG assay is high, a routine test for anti-Toxocara IgG might be necessary for Korean patients with intermediate and posterior uveitis.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Animals ; Antibodies, Anti-Idiotypic/*blood ; Aqueous Humor/parasitology ; Child ; Enzyme-Linked Immunosorbent Assay ; Eye Infections, Parasitic/*diagnosis/epidemiology/parasitology ; Female ; Follow-Up Studies ; Humans ; Immunoglobulin G/blood/*immunology ; Incidence ; Male ; Middle Aged ; Republic of Korea/epidemiology ; Retrospective Studies ; *Tertiary Care Centers ; Toxocara canis/*immunology/isolation & purification ; Toxocariasis ; Uveitis/*diagnosis/epidemiology/parasitology ; Young Adult