Investigation of anti-Toxocara antibodies in epileptic patients and comparison of two methods: ELISA and Western blotting

Case-Control Study to Assess the Association between Epilepsy and Toxocara Infection/Exposure

Although causes and etiology of epilepsy are mostly obscure, some zoonotic parasites, such as Toxocara species, have been proposed as a risk factor for this disease. Here, we conducted an age-matched case-control study to evaluate whether there is an association between epilepsy and the presence of serum antibodies to Toxocara in incident cases. We included 94 idiopathic epileptic patients as cases, and—from the same geographical region—88 people with no own history of epilepsy or neurological disease as control subjects. Epilepsy was confirmed by a physician using the International League Against Epilepsy (ILAE) definition. All participants were screened for the anti-Toxocara IgG serum antibody by enzyme-linked immunosorbent assay (ELISA). Univariate and mutltivariate statistical analyses were applied to calculate the crude and adjusted odds ratios (OR) and 95% confidence intervals (CIs). Anti-Toxocara serum antibody was detected in 37 epileptic patients and in 23 control subjects, giving respective seroprevalences of 39.3% (95% CI, 29.4–49.9%) and 26.1% (95% CI, 17.3–36.5%), respectively. Adjusted multivariate logistic regression analysis estimated an OR of 2.38 (95% CI, 1.25–4.63), indicating a significant association between epilepsy and Toxocara seropositivity. There was also a significant association between seropositivity to Toxocara and partial (OR, 2.60; 95% CI, 1.14–6.04) or generalized (OR, 2.17; 95% CI, 1.09–4.40%) seizures. Findings from the present study of incident epileptic cases support previous studies proposing that Toxocara infection/exposure is a risk factor for epilepsy. However, further well-designed population-based surveys and mechanistic/experimental studies in animal models are required to better understand the reason(s) for this association.

A new ELISA and western blot technique based on recombinant TES antigen and/or larval antigen for the detection of toxocariasis in humans

Serological antibody detection by enzyme-linked immunosorbent assay (ELISA)- and immunoblot-based methods constitutes the best indicator of human Toxocara infection. Nevertheless, the availability of serological tests, particularly western blots (WB), evaluated for sensitivity and specificity is limited. Therefore, an Anti-Toxocara-ELISA immunoglobulin g (IgG) prototype (Proto-ELISA) and an Anti-Toxocara-Westernblot (IgG) prototype (Proto-WB) were evaluated by testing 541 human sera pre-determined for Toxocara infection by an established in-house Anti-Toxocara-ELISA (IH-ELISA). To evaluate sensitivity and specificity of the newly developed ELISA and WB prototypes, results were compared to IH-ELISA and a commercial WB (Com-WB). Compared to the IH-ELISA, a sensitivity of 93.1% (229/246) and a specificity of 94.6% (279/295) of the Proto-ELISA with a Cohen's κ of 0.88 were obtained. The sensitivity of the Proto-WB was 76.7% (240/313) and specificity was 99.6% (227/228) with a Cohen's κ of 0.73 compared to those of Com-WB. A comparison to the IH-ELISA revealed 91.5% (225/246) sensitivity and 94.6% (279/295) specificity of the Proto-WB with a Cohen's κ of 0.86. Cross-reactivity was observed for some samples positive for Ascaris and Trichinella spp. in the Proto-ELISA, Proto-WB and Com-WB. Overall, the evaluated ELISA and WB prototypes showed high sensitivity and specificity, indicating high reliability of these newly developed tests.

Zoonotic and vector-borne parasites and epilepsy in low-income and middle-income countries

Zoonotic and vector-borne parasites are important preventable risk factors for epilepsy. Three parasitic infections - cerebral malaria, Taenia solium cysticercosis and onchocerciasis - have an established association with epilepsy. Parasitoses are widely prevalent in low-income and middle-income countries, which are home to 80% of the people with epilepsy in the world. Once a parasitic infection has taken hold in the brain, therapeutic measures do not seem to influence the development of epilepsy in the long term. Consequently, strategies to control, eliminate and eradicate parasites represent the most feasible way to reduce the epilepsy burden at present. The elucidation of immune mechanisms underpinning the parasitic infections, some of which are parasite-specific, opens up new therapeutic possibilities. In this Review, we explore the pathophysiological basis of the link between parasitic infections and epilepsy, and we consider preventive and therapeutic approaches to reduce the burden of epilepsy attributable to parasitic disorders. We conclude that a concerted approach involving medical, veterinary, parasitological and ecological experts, backed by robust political support and sustainable funding, is the key to reducing this burden.

Establishment of an Experimental Procedure for Preparing Trial Serum Samples for the Specific Serodiagnosis of Toxocara canis for External Quality Assessment Schemes

Background

External quality assessment (EQA) provides evidence of reliable, accurate, and precise results for customers using the diagnostic test for Toxocara canis. Objective. To establish a procedure for producing standard Toxocara canis serum samples for serodiagnostic testing in EQA.

Methods

The collected serum samples to contain anti-Toxocara canis serum samples for serodiagnostic testing in EQA. F-test and a T-test were applied to evaluate their homogeneity and stability.

Results

Among eleven samples positive by ELISA, ten of them were confirmed via Western blotting by positive reaction with 5 specific Toxocara canis serum samples for serodiagnostic testing in EQA. Toxocara canis serum samples for serodiagnostic testing in EQA. p > 0.05). Samples produced by both methods were stable for 7 days at 30°C (p > 0.05). Samples produced by both methods were stable for 7 days at 30°C (

Conclusion

Specific serodiagnosis samples of anti-Toxocara canis antibodies for EQA could be produced that possessed homogeneity and stability lasting for 3 months and 6 months by the freeze-drying and freezing methods, respectively. At 30°C, the samples produced by both methods were stable for 7 days, suitable for delivery to remote laboratories.Toxocara canis serum samples for serodiagnostic testing in EQA.

Sensitivity and specificity of recombinant proteins in Toxocara spp. for serodiagnosis in humans: Differences in adult and child populations

Toxocariasis is a neglected zoonosis that affects children and adults. Recombinant proteins have been widely investigated for diagnosis, achieving high sensitivity and specificity in an overall population; however, little is known about age as a factor in its application. This study aims to investigate the diagnostic potential of Toxocara canis TES-30 and TES-120 recombinant proteins in humans, differentiating between its performance in children and adults. Serum samples collected from children and adults seropositive to Toxocara spp. were tested with indirect ELISA using T. canis TES-30 and TES-120 recombinant proteins produced in Escherichia coli. While rTES-30 sensitivity was not affected by age (81.8% in children and 87% in adults), rTES-120 sensitivity severely decreased in children to only 63.6%, down from 95.7% in adults. Furthermore, the sensitivity of rTES-30 increased to 97.8% after Western blotting confirmation. High specificity (>94%) against other geohelminths was reported for both recombinant proteins. Our study favors the use of rTES-30 with total IgG as the primary antibody in an indirect ELISA assay as a tool for epidemiological human studies.

Updated evidence of the association between toxocariasis and epilepsy: Systematic review and meta-analysis

Objective

To gain further insight on the association between human toxocariasis and epilepsy in light of the new evidence in the last years.

Methods

A systematic review was conducted without date and language restriction in the following electronic databases: MEDLINE (PubMed), Ingenta Connect, Science Direct (Elsevier), RefDoc, Scopus, HighWire, Scielo and the database of the Institute of Neuroepidemiology and Tropical Neurology of the Limoges University (IENT). Two investigators independently conducted the search up to November 2017. A pooled odds ratio (OR) was estimated using a random effects model. Meta-regression was conducted to investigate potential sources of heterogeneity.

Results

Database search produced 204 publications. Eleven case-control studies were included that were carried out in 13 countries worldwide. A total number of 4740 subjects were considered (2159 people with epilepsy and 2581 people without epilepsy). The overall pooled OR was 1.69 (95% CI 1.42–2.01) for the association between epilepsy and Toxocara spp. seropositivity. A positive association was constantly reported in the restricted analysis (WB as confirmatory or diagnostic test, younger population, and population–based studies). Meta-regression showed no statistically significant association between covariates and outcome.

Conclusion

The updated meta-analysis provides epidemiological evidence of a positive association between Toxocara seropositivity and epilepsy. New surveys supported the association, mainly population-based studies. On this basis, health strategies to reduce the impact of Toxocara spp are strongly advised. Further research should be performed to understand the physiopathological mechanisms of toxocara-associated epileptogenesis.

Human toxocariasis is a parasitic zoonosis caused by the larval stages of Toxocara canis (T. canis), the common roundworm of dogs, and by the roundworm of cats, Toxocara cati (T. cati). Toxocariasis is one of the most prevalent helminthiasis worldwide. Humans become infected by the ingestion of contaminated food or soil or by direct contact with dogs and cats. Epilepsy is the most common chronic neurological disorder worldwide with a global estimate of about 70 million cases of lifetime epilepsy. Early studies suggested high rate of toxocara exposure (toxocara seropositivity) among people with epilepsy. Despite several studies support the possible role of toxocariasis in the incidence of epilepsy, this association is still debated. We updated our previous research to gain further insight on the association. This study provides new evidence of a positive association between the two diseases. On this basis, health strategies to reduce the impact of Toxocara spp are strongly advised. Further studies are necessary to clarify the role of certain parasites in epilepsy.

Trend of toxocariasis in Iran: a review on human and animal dimensions

One of the neglected soil and/or food-borne diseases with international public health importance is toxocariasis. Human cases are being increasingly reported from Asian, African, Oceania, European and the American countries. Hence, human toxocariasis (HT) is now considered as a major zoonosis with global and regional importance. In Iran, human and animal toxocariasis is an endemic disease with clinical and epidemiologic health problem aspects. Doubtless, understanding the epidemiology and the trend of this important parasitic disease and its affecting factors will provide the establishment of effective prevention and control programs. To better understand the trend of toxocariasis researches in Iran, this study was performed to analyze different aspects of this zoonotic disease including history, life cycle, species, human animals and environmental studies, diagnostic aspects and treatments to find out the gaps, including different aspects of clinical sings in human patients, new and specific recombinant antigens based on the native antigens, new diagnostic tools, especially rapid diagnostic tests, paratenic hosts status and new treatment procedures which is necessary to be investigated in the future studies on this important zoonotic disease.

Cerebral Toxocariasis: Silent Progression to Neurodegenerative Disorders?

Toxocara canis and T. cati are highly prevalent nematode infections of the intestines of dogs and cats. In paratenic hosts, larvae do not mature in the intestine but instead migrate through the somatic tissues and organs of the body. The presence of these migrating larvae can contribute to pathology. Toxocara larvae can invade the brains of humans, and while case descriptions of cerebral toxocariasis are historically rare, improved diagnosis and greater awareness have contributed to increased detection. Despite this, cerebral or neurological toxocariasis (NT) remains a poorly understood phenomenon. Furthermore, our understanding of cognitive deficits due to toxocariasis in human populations remains particularly deficient. Recent data describe an enhanced expression of biomarkers associated with brain injury, such as GFAP, AβPP, transforming growth factor β1 (TGF-β1), NF-L, S100B, tTG, and p-tau, in mice receiving even low doses of Toxocara ova. Finally, this review outlines a hypothesis to explore the relationship between the presence of T. canis larvae in the brain and the progression of Alzheimer's disease (AD) due to enhanced AD-associated neurodegenerative biomarker expression.

Frequency of Toxoplasma and Toxocara Sp. Antibodies in Epileptic Patients, in South Western Iran

OBJECTIVE

Epilepsy is a disorder of the brain characterized by an enduring predisposition to generate seizures. Infectious agents are mentioned in its etiology. With identifying and appropriate treatment of these infectious agents, preventing their secondary outcomes, including seizure is possible. This study was conducted to determine frequency of anti-Toxoplasma antibodies (IgG, IgM) and anti-Toxocara antibody (IgG) in epileptic patients.

MATERIALS & METHODS

Study sample consisted of 141 epileptic patients and 144 healthy people. After obtaining informed consents and completing demographic questionnaire, serum samples were taken from participants. The diagnostic test of Toxoplasma IgG & IgM and Toxocara antibodies was performed under the same conditions using ELISA method in a qualified private laboratory. Samples from patients and control groups with positive ELISA test in terms of anti-Toxocara antibody were also used for confirmatory Western blot test.

RESULT

According to ELISA results, 28 (19.85%) epileptic patients and 2(1.38%) of healthy people had anti-Toxocara antibodies (P<001), while 39 (30.46%) of the control group people and 14.18% of patients had anti-Toxoplsma antibodies (P=0.001).

CONCLUSION

Frequency of anti-Toxoplasma gondii is lower in epileptic than healthy individuals and this result is contrary to investigations that have reported higher levels of this antibody in such patient groups. ELISA results for Toxocara showed that the frequency of anti-Toxocara antibody in epileptic patients might empower the probability that this parasite may cause central nervous system damage. Western blotting has high specificity and is a proper confirmative method for diagnosis of toxocariasis.

Reduced ABCB1 Expression and Activity in the Presence of Acrylic Copolymers

PURPOSE

P-glycoprotein (P-gp; ABCB1), an integral membrane protein in the apical surface of human intestinal epithelial cells, plays a crucial role in the intestinal transport and efflux leading to changes in the bioavailability of oral pharmaceutical compounds. This study was set to examine the potential effects of three Eudragits RL100, S100 and L100 on the intestinal epithelial membrane transport of rhodammine-123 (Rho-123), a substrate of P-gp using a monolayer of human colon cancer cell line (Caco-2).

METHODS

The least non-cytotoxic concentrations of the excipients were assessed in Caco-2 cells by the MTT assay. Then the transepithelial transport of Rho-123 across Caco-2 monolayers was determined with a fluorescence spectrophotometer. Besides, the expression of the P-gp in cells exposed to the polymers was demonstrated using Western-blotting analysis.

RESULTS

Treatment of cells with Eudragit RL100 and L100 led to a very slight change while Eudragit S100 showed 61% increase in Rho-123 accumulation (P<0.001) and also reduced transporter expression.

CONCLUSION

Our studies suggest that using proper concentrations of the Eudragit S100 in drug formulation would improve intestinal permeability and absorption of p-gp substrate drugs.

Investigation of anti-Toxocara and anti-toxoplasma antibodies in patients with schizophrenia disorder

Objective. The aim of the present study was to examine the relationship between Toxoplasma gondii and Toxocara spp. infections in patients with schizophrenia disorder. Method. A total of 100 patients with schizophrenia disorder and 95 healthy individuals participated in the study. Participants were tested for the presence of anti-T. gondii and anti-Toxocara spp. antibodies by ELISA and Western blotting. Data were analyzed using Chi-square test and Fisher 9 s exact test. Results. There were no differences in T. gondii IgG seroprevalence between patients with schizophrenia and healthy individuals (P = 0.1), but there were differences in seroprevalence between males and females with schizophrenia (P = 0.009). In contrast, Toxocara spp. IgG seroprevalence was greater in patients with schizophrenia disorder than in healthy individuals (P = 0.02), but there were no differences in seroprevalence between men and women with schizophrenia (P = 0.5). Finally, there were no differences in seroprevalence of T. gondii or Toxocara spp. IgG among different subtypes of schizophrenia, various age groups, residential area, or clinical course of treatment (P > 0.05). Conclusion. The present study suggests that patients with schizophrenia disorder are at elevated risk of Toxocara spp. infection. Moreover, contamination with T. gondii is a risk factor for schizophrenia in women.