Alterations of plasma circulating microRNAs in BALB/c mice with Toxocara canis visceral and cerebral larva migrans.

BACKGROUND: Human toxocariasis is a neglected parasitic disease characterised by the syndromes visceral, cerebral, and ocular larva migrans. This disease is caused by the migrating larvae of Toxocara roundworms from dogs and cats, affecting 1.4 billion people globally. Via extracellular vesicles (EVs), microRNAs have been demonstrated to play roles in host-parasite interactions and proposed as circulating biomarkers for the diagnosis and follow-up of parasitic diseases. METHODS: Small RNA-seq was conducted to identify miRNAs in the infective larvae of T. canis and plasma EV-containing preparations of infected BALB/c mice. Differential expression analysis and target prediction were performed to indicate miRNAs involved in host-parasite interactions and miRNAs associated with visceral and/or cerebral larva migrans in the infected mice. Quantitative real-time polymerase chain reaction (PCR) was used to amplify circulating miRNAs from the infected mice. RESULTS: This study reports host and parasite miRNAs in the plasma of BALB/c mice with visceral and cerebral larva migrans and demonstrates the alterations of these miRNAs during the migration of larvae from the livers through the lungs and to the brains of infected mice. After filtering unspecific changes in an irrelevant control, T. canis-derived miRNAs and T. canis infection-induced differential miRNAs are predicted to modulate genes consistently involved in mitogen-activated protein kinase (MAPK) signalling and pathways regulating axon guidance and pluripotency of stem in the infected mice with visceral and cerebral larva migrans. For these plasma circulating miRNAs predicted to be involved in host-parasite crosstalk, two murine miRNAs (miR-26b-5p and miR-122-5p) are experimentally verified to be responsive to larva migrans and represent circulating biomarker candidates for visceral and cerebral toxocariasis in BALB/c mice. CONCLUSIONS: Our findings provide novel insights into the crosstalk of T. canis and the mammalian host via plasma circulating miRNAs, and prime agents and indicators for visceral and cerebral larva migrans. A deep understanding of these aspects will underpin the diagnosis and control of toxocariasis in humans and animals.

The impact of Toxocara-seropositivity on attention and motor skills in children with attention-deficit hyperactivity disorder.

BACKGROUND: The study aims to compare neurological soft signs and executive functions between Toxocara-seropositive and seronegative groups in children with attention-deficit/hyperactivity disorder. METHODS: The study included 60 boys with ADHD, aged 7-12. After blood samples were taken, the Stroop Color Word Test and Judgment of Line Orientation test (JLOT) were implemented to measure executive functions. Neurological soft signs were evaluated with Physical and Neurological Examination for Subtle Signs (PANESS). RESULTS: Serological tests were positive for Toxocara antibodies in 20 cases. There was no significant difference between Toxocara seropositive and seronegative regarding age, socioeconomic status, developmental stages, and ADHD severity. However, Toxocara-seropositive children had higher Stroop time and Stroop interference scores and lower JLOT scores than Toxocara-seronegative children. Furthermore, Toxocara-seropositive children exhibited more neurological soft signs, such as gait and station abnormalities, dysrhythmia, and a longer total time in timed movements compared to Toxocara-seronegative children. CONCLUSION: Our study indicates a link between Toxocara-seropositivity and impaired neurological soft signs and executive functions in ADHD. Further research is needed to understand ADHD mechanisms, develop practical treatments considering immunological factors, and thoroughly evaluate how Toxocara seropositivity affects executive functions and motor skills in children with ADHD.

Serosurvey of anti-Toxocara antibodies and risk factors in adolescent and adult pregnant women of southeastern Brazil.

Toxocariasis is worldwide endemic parasitic anthropozoonosis with high risk to those in in vulnerable populations and particularly during pregnancy and childhood. Although the prevalence of anti-Toxocara spp. antibodies has been extensively studied, risk factors of pregnant women of different ages remains to be established. This study was designed to i) assess the presence of anti-Toxocara spp. antibodies in pregnant women that presented to the public health system in a city of southeastern Brazil, and ii) determine the risk factors for toxocariasis in adolescent and adult pregnant women. This cross-sectional study included 280 pregnant women (71 aged up to and including 17 years [adolescents] and 209 aged 18 years and older [adults]). Pregnant women voluntarily agreed to complete a socioeconomic questionnaire and provide serum samples. Anti-Toxocara IgG antibodies were screened by Enzyme-Linked Immunosorbent Assay (ELISA). Univariable and multivariable logistic regression models were performed to assess the risks for toxocariasis. Overall, 20.7% of pregnant women were seropositive (33.8% of adolescents and 16.3% of adults). Prevalence in pregnant adolescents was 2.6-fold higher than in adults (Odds ration [OR]: 2.63; 95% CI: 1.42-4.86, p = 0.003). Multivariate analysis revealed that contact with soil (p = 0.01; OR = 4.76) and being in the first trimester of pregnancy (p = 0.03; OR = 0.17) had significantly greater risk of toxocariasis for adolescents, and attainment of elementary through middle school education level (p = 0.05; OR = 8.33) was a risk factor in adult pregnant women. Toxocariasis is likely underreported and neglected in adolescent pregnant women; this age group should always be monitored for toxocariasis and correspondent clinical signs, particularly at late pregnancy.

The kinetic profile of clinical and laboratory findings and treatment outcome of patients with toxocariasis.

OBJECTIVES: Human toxocariasis is a widespread zoonosis for which a chemotherapy decision and therapy effectiveness are difficult to determine. We aimed to investigate the kinetic profile of clinical and laboratory findings and treatment outcome of patients with toxocariasis in Vietnam. METHODS: The prospective study was conducted between October 2017 and June 2019. The diagnosis of toxocariasis was established based on clinical, laboratory (eosinophilia, raised IgE concentration) and serological (positive Toxocara IgG ELISA) evaluation as well as the exclusion of another helminthic co-infection. The patients were followed up after seven days, then one, three and six months after chemotherapy by thiabendazole. RESULTS: The study involved 80 patients with a mean age of 41.6 ± 15.2 years of whom 58.8% were female. At three and six months after chemotherapy, most patients demonstrated resolution of clinical signs and symptoms, eosinophil count and IgE concentration but not in the proportion of IgG seropositivity. Skin lesions and eosinophilia resolved earlier than the other symptoms (one month after treatment). About four-fifths of the patients were "cured" after three and six months of follow-up; 33.8% showed side effects to thiabendazole therapy but no severe events were reported. The most common adverse reaction was neurologic symptoms followed by gastrointestinal or skin manifestations which lasted as long as 4 days. CONCLUSIONS: In toxocariasis patients, cutaneous manifestations and eosinophilia resolve more rapidly than other clinical and laboratory findings while IgG titre has a very slow kinetic after therapy. Thiabendazole seems to be a potential alternative for the treatment of human toxocariasis.

Serosurvey and associated risk factors of anti-Toxocara spp. antibodies in bovines from slaughterhouses of southeastern Brazil.

BACKGROUND: Toxocariasis, caused by a nematode species of the genus Toxocara, has been described as one of the most prevalent zoonotic helminthiases worldwide. Human transmission may occur by ingesting Toxocara spp. larvae from raw or undercooked meat or organs; however, no comprehensive serosurvey study has been conducted to date investigating the role of cattle as paratenic hosts. The aim of the study reported here was to assess the prevalence of anti-Toxocara spp. antibodies and associated risk factors in bovines from two slaughterhouses located in Presidente Prudente, southeastern Brazil. METHODS: Blood samples were collected and tested by indirect enzyme-linked immunosorbent assay (ELISA). Cattle farmers voluntarily responded to an epidemiologic questionnaire. RESULTS: Overall, 213 of the 553 (38.5%) bovine samples were assessed as seropositive for anti-Toxocara spp. antibodies by indirect ELISA. Multivariate analysis revealed that the source of beef cattle and the presence of dogs or cats at the farm were associated with seropositivity. The use of feedlot systems was associated with lower likelihood of seropositivity. CONCLUSIONS: These results indicate a high level of anti-Toxocara seropositivity in slaughterhouse cattle, with potentially contaminated meat posing an infection risk to humans. In addition, the presence of dogs and cats where the slaughtered beef cattle were raised was statistically associated with bovine seropositivity, probably due to the overlapping environment at the farm and the lack of pet deworming. The use of feedlot systems was a protective factor likely due to the absence of dog and cat contact, elevated feeding troughs that avoid contact with contaminated soil or grass, and younger age at slaughter of feedlot cattle. In summary, bovines may be used as environmental sentinels of Toxocara spp. contamination, and high seropositivity of slaughterhouse cattle may indicate a potential risk of human toxocariasis through the ingestion of raw or undercooked contaminated meat.

The association between seropositivity to human toxocariasis and childhood asthma in northern Iran: a case-control study.

BACKGROUND: Besides the well-known risk factors, Toxocara infection is thought to play a significant etiological role in the development of childhood asthma. To further explore this association, the prevalence of Toxocara infection in sera of asthmatic children and healthy controls in northern Iran was investigated. METHODS: In this case-control study, cases were 145 physician-confirmed asthmatic children diagnosed according to the Global Initiative for Asthma (GINA) guidelines. Controls were 115 age-sex-residence-matched children who did not have physician-diagnosed asthma. The presence of anti-Toxocara immunoglobulin G (IgG) was tested using enzyme-linked immunosorbent assay. Univariate and multivariate logistic regression methods were used for case-control comparisons. RESULTS: Seropositivity rate was 4.1% (95% CI, 3.4-4.7%) in asthmatic children and 0.86% (95% CI, 0.71-1.0%) in controls, suggesting a strong association (P-value < 0.02). Moreover, Toxocara infection was not significantly more prevalent (P-value = 0.12) in children with moderate sustainable asthma (9.3%, 3/32) than in children with mild sustainable asthma (2.3%, 3/113). Mean total immunoglobulin E (IgE) level was significantly higher in Toxocara-infected children (222.3 ± 367.1) than in non-infected children (143.19 ± 218.05) in the case group (P-value < 0.05). CONCLUSIONS: Our findings indicated that Toxocara infection can play an important role in childhood asthma. Further experimental and epidemiological studies are needed to clarify this hypothesis.

Seroprevalence of Toxoplasma gondii and Toxocara spp. infections among pregnant women with and without previous abortions in the west of Iran.

AIM: In spite of the importance of toxoplasmosis and toxocariasis among the high-risk groups, such as pregnant women, the infections are categorized as a neglected tropical disease by the World Health Organization. Toxoplasma gondii and Toxocara spp. infections can cause systemic and ocular diseases in infants during pregnancy. In this study, we investigated seroprevalence and risk factors of toxoplasmosis, toxocariasis and their co-infection in pregnant women and non-pregnant women referred to the healthcare facilities of Ilam province, west of Iran. METHODS: A total of 378 sera samples (189 pregnant women and 189 non-pregnant women) was investigated for the presence of IgG antibodies against T. gondii and Toxocara spp. by Enzyme-linked immunosorbent assay (ELISA). The samples of all pregnant women with abortion (56 cases) were also evaluated for IgM anti-toxoplasmosis antibody by ELISA method. Moreover, associated factors were obtained from the participant's questionnaires. Data analysis for this study was performed using the spss software version 20. RESULTS: Seroprevalence of T. gondii, Toxocara spp., and their co-infection in pregnant women was 39.7%, 21.2% and 9.5%, respectively. Regarding the risk factors, the contact with a cat (P = 0.04) and dog (P = 0.00) were significantly associated with T. gondii and Toxocara spp., respectively. CONCLUSION: This study highlighted the importance of serological diagnosis before pregnancy. Moreover, we believe that more epidemiological studies are needed for a better understanding of overlaps between T. gondii and Toxocara spp. in pregnant women.

Seroprevalence of Larval Toxocarosis in the Czech Republic.

BACKGROUND: Larval toxocarosis (LT), a zoonotic disease transmitted by dogs, cats, and other carnivores, is caused by roundworms of the genus Toxocara. Humans become infected by ingesting embryonated eggs of this parasite. In this study, we present data on the seroprevalence of LT in the Czech Republic collected by the National Reference Laboratory for Tissue Helminthoses in 2012-2016. METHODS: Using enzyme-linked immunosorbent assay, a total of 4428 adults and children with or without clinical symptoms were examined for the presence of IgG antibodies against Toxocara canis excretory-secretory antigens. RESULTS: Of all the persons examined, specific Toxocara antibodies were detected in 160 (3.6%) individuals. There were, however, significant differences between various regions, with seropositivity rates ranging from 1.4 to 7.5%. CONCLUSION: In comparison to studies from 1998 and 2004, our results suggest a decrease in overall Toxocara seroprevalence in the Czech population, whereby the rates are similar to or even lower than rates in some other Central European countries.

Electrochemical microfluidic immunosensor based on TES-AuNPs@Fe3O4 and CMK-8 for IgG anti-Toxocara canis determination.

We report a microfluidic immunosensor for the electrochemical determination of IgG antibodies anti-Toxocara canis (IgG anti-T. canis). In order to improve the selectivity and sensitivity of the sensor, core-shell gold-ferric oxide nanoparticles (AuNPs@Fe3O4), and ordered mesoporous carbon (CMK-8) in chitosan (CH) were used. IgG anti-T. canis antibodies detection was carried out using a non-competitive immunoassay, in which excretory secretory antigens from T. canis second-stage larvae (TES) were covalently immobilized on AuNPs@Fe3O4. CMK-8-CH and AuNPs@Fe3O4 were characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive spectrometry, cyclic voltammetry, electrochemical impedance spectroscopy, and N2 adsorption-desorption isotherms. Antibodies present in serum samples immunologically reacted with TES, and then were quantified by using a second antibody labeled with horseradish peroxidase (HRP-anti-IgG). HRP catalyzes the reduction from H2O2 to H2O with the subsequent oxidation of catechol (H2Q) to p-benzoquinone (Q). The enzymatic product was detected electrochemically at _100 mV on a modified sputtered gold electrode. The detection limit was 0.10 ng mL-1, and the coefficients of intra- and inter-assay variation were less than 6%, with a total assay time of 20 min. As can be seen, the electrochemical immunosensor is a useful tool for in situ IgG antibodies anti-T. canis determination.

Toxocara sero-prevalence and its relationship with allergic asthma in asthmatic patients in north-eastern Iran.

Toxocariasis is an important neglected tropical disease that has been suggested as a possible etiologic agent of asthma. The objective of the present study was to investigate possible significant association between Toxocara seroprevalence and asthma in a clinic-based case-control study. Blood samples were collected from human subjects aged 5-70 years, 50 of whom had signs of asthma and 50 of whom had no signs of asthma. Risk factors for asthma and Toxocara spp. infection were assessed by a questionnaire given to each patient. Blood samples were analysed to measure levels of anti-Toxocara spp. immunoglobulin G (IgG). Patients with bronchial asthma were observed to have higher Toxocara spp. seropositivity than that of the non-asthmatic controls (6 vs 2%, P = 0.47). The mean anti-Toxocara spp. antibody titre was not significantly higher in patients with bronchial asthma than in individuals without asthma (P = 0.395, 95% CI = 0.579-1.45). There was no significant difference in the mean age, sex, social class, exposure to smoking and presence of domestic dog or cat at home between the two groups (P ≥ 0.05). The presence of anti-Toxocara spp. IgG was statistically associated with higher blood eosinophils, but it was not associated with asthma (P ≥ 0.05). The observed relationship between exposure to Toxocara spp. infection and bronchial asthma in Iranian patients warrants further evaluation. An understanding of any potential influence on the pathogenesis of human asthma provides a potential avenue for prevention.

Toxocariasis ocular. A propósito de un caso / Ocular toxocariasis. Case report

RESUMEN Se presentó un caso clínico de un paciente de seis años de edad, con toxocariasis ocular. La manifestación clínica fue disminución de la agudeza visual monocular. El fondo de ojo izquierdo mostró un granuloma retiniano periférico, asociado a un desgarro retiniano perilesional. El examen oftalmológico confirmó el diagnóstico de Toxocara ocular. El paciente fue tratado posteriormente mediante corticoides sistémicos y fotocoagulación láser focal en el desgarro retiniano (AU).

ABSTRACT We present the clinical case of a male patient, aged 6 years, with ocular toxocariasis. The clinical manifestation was monocular visual acuity decrease. The left ocular fundus showed a peripheral retina granuloma, associated to a perilesional retinal tear. The ophthalmological examination confirmed the diagnosis of ocular Toxocara. After that the patient was treated using systemic corticoids and focal laser coagulation in the retinal tear (AU).

Toxocariasis ocular. A propósito de un caso / Ocular toxocariasis. Case report

RESUMEN Se presentó un caso clínico de un paciente de seis años de edad, con toxocariasis ocular. La manifestación clínica fue disminución de la agudeza visual monocular. El fondo de ojo izquierdo mostró un granuloma retiniano periférico, asociado a un desgarro retiniano perilesional. El examen oftalmológico confirmó el diagnóstico de Toxocara ocular. El paciente fue tratado posteriormente mediante corticoides sistémicos y fotocoagulación láser focal en el desgarro retiniano (AU).

ABSTRACT We present the clinical case of a male patient, aged 6 years, with ocular toxocariasis. The clinical manifestation was monocular visual acuity decrease. The left ocular fundus showed a peripheral retina granuloma, associated to a perilesional retinal tear. The ophthalmological examination confirmed the diagnosis of ocular Toxocara. After that the patient was treated using systemic corticoids and focal laser coagulation in the retinal tear (AU).

New insight into the diagnostic cut-off value of serum anti-Toxocara IgG for ocular toxocariasis in uveitis patients.

Uveitis is one of the commonest causes of vision loss worldwide and its exact etiology is still not clarified in most patients. The current study is a trial to assess the efficacy of serum anti-Toxocara immunoglobulin G (IgG) by enzyme-linked immunosorbent assay (ELISA) as a diagnostic tool for ocular toxocariasis (OT) and to detect OT prevalence and the associated ocular manifestations in sera of patients with uveitis. One hundred and twelve patients (62 females and 50 males) with uveitis were diagnosed by ophthalmologists, radiologists and rheumatologists according to ocular manifestations, laboratory and radiological investigations. Serum anti-Toxocara IgG titers were determined by ELISA in sera of all patients. Our results revealed that OT is highly associated with intermediate and posterior uveitis. Children and young adult females, especially those residing in rural areas, complained mainly of diminution of vision in the left eye, with strabismus and leukocoria. At a cut-off value of 0.258, the sensitivity and specificity of IgG ELISA were 93.3% and 100%, respectively. In conclusion, at a novel cut-off value of 0.258 the serum anti-Toxocara IgG ELISA is predicted to be a diagnostic tool for OT regarding sensitivity and specificity. Also, it has potential importance in the interpretation and differential diagnosis of OT. Thus, serum anti-Toxocara IgG ELISA should be a routine test for screening of suspected cases.

Seroprevalence and risk factors for Toxocara infection among children in a rural community in Fars province, southern Iran.

The current study was performed to find out the seroprevalence of Toxocara infection in children living in a rural community in Fars province, southern Iran. Venous blood was taken from 617 children and evaluated for anti-Toxocara antibodies, using an ELISA system. Of the 617 studied children, 318 (51.5%) were boys and 299 (48.5%) were girls. Mean age of the participants was 9.2 (±10.7) years. Most cases of the recruited subjects (37.4%) were in the age group of 0-5 years. Anti-Toxocara antibodies were detected in sera of 39 (6.3%) of children. From these, 23 (62.2%) were boys and 14 (37.8%) were girls. The infection rate was almost the same in different age groups. No statistically significant differences were seen between seropositivity to Toxocara infection and gender or age of the participants. Dogs or cats ownership was not associated with Toxocara seropositivity. The adjusted associations of the study variables suggested that the visceral leishmaniasis (VL) seropositivity is significantly associated with the seroprevalence of Toxocara infection (P < 0.001). Findings of the current study revealed that Toxocara infection is a common infection among children in the studied rural community in Iran. Preventive measurements are necessary to minimize the rate of Toxocara infection in children in such communities.

Seroprevalence of ToxocaraCanis in Asthmatic Children and its Relation to the Severity of Diseases - a Case-Control Study.

Background: Toxocariasis is a common parasitic infectionworldwide even in developed countries. Through this health problem, the immune system is triggered and the antibody is produced, leading to some hypersensitive situations like asthma. In the present study, we tried to show a correlation between Toxocara Canis (T. canis) seropositivityand asthma in Isfahan city. Methods: This research is a cross-sectional study involving 40 asthmatics and 46 non-asthmatic cases aged 2-18 years. In all cases, T. canis IgG level was measured using enzyme-linked immunosorbent assay (ELISA) and compared between two groups. Results: The seroprevalence of IgG anti-T. canis antibodies were 45%in the asthmatic patients and 21.7% in thecontrols (P= 0.022). The more severe asthmatic patients had significantly more risk for T. canis seropositivity (P= 0.019). In the asthmatic patients, there was a significant correlation between Toxocara seropositivity and goingto park or playground (P= 0.001). Conclusion: In this study, we found a significantly positive serology of T. canis in asthmatic children especially in more severe disease. To verify the etiologic role of Toxocara in asthma, more advanced studies are needed.

Asthma and Seroconversion from Toxocara spp. Infection: Which Comes First?

The aim of this study was to estimate the incidence of seroconversion of Toxocara spp. infection and related variables. We conducted a cohort study of 77 children aged 2-12 years who had negative serology in a previous cross-sectional study. Univariate and bivariate analyses were performed to describe the cohort, using socioeconomic, behavioral, and health conditions as variables. Logistic regression analysis was performed using seroconversion as the dependent variable, and the remaining variables are treated as independent variables. Asthma was the only independent variable that showed an association with seroconversion, with an odds ratio = 3.57 (1.01-12.6). The incidence of seroconversion from Toxocara spp. infection in the children followed was 10.4 per 100 per year. Previous studies reporting an association of asthma with toxocariasis have only been carried out using cross-sectional studies. Therefore, this study is one of only a few describing the incidence of seroconversion from Toxocara spp. infection, which is relevant for understanding the burden of this parasite.

Prolactin as immune cell regulator in Toxocara canis somatic larvae chronic infection.

Toxocariasis is a zoonotic disease produced by ingestion of larval Toxocara spp. eggs. Prolactin (PRL) has been considered to have an important role in Toxocara canis infection. Recent evidence has found that PRL directly can increase parasite growth and differentiation of T. canis The present study, evaluated the effect of high PRL levels on the immune system's response and parasites clearance in chronic infection. Our results showed that hyperprolactinemia did not affect the number of larvae recovered from several tissues in rats. Parasite-specific antibody production, showed no difference between the groups. Lung tissue presented eosinophilic granulomas typical of a chronic infection in all the experimental groups. Flow cytometry analysis was made in order to determine changes in the percentage of innate and adaptive immune cell subpopulations in the spleen, peripheric (PLN) and mesenteric (MLN) lymphatic nodes. The results showed a differential effect of PRL and infection on different immune compartments in the percent of total T cells, T helper cells, T cytotoxic cells, B cells, NK cells, and Tγδ cells. To our knowledge, for the first time it is demonstrated that PRL can have an immunomodulatory role during T. canis chronic infection in the murine host.

Epidemiological, clinical and laboratory features of toxocariasis in school children from Aragua State, Venezuela.

Background: Toxocariasis is a widespread zoonosis caused by canine and feline Toxocara spp. In Venezuela, seroepidemiological studies in Aragua State have been carried out only in preschool children. The objective of this study was to determine the prevalence of anti-Toxocara spp. antibodies and identify clinical symptoms and risk factors of Toxocara spp. infection in school children in two municipalities of Aragua State of Venezuela. Methods: A cross-sectional field study with 259 children between 6 and 12 y of age was conducted in six schools in Aragua State. Immunoglobulin G antibodies against Toxocara spp. by enzyme-linked immunosorbent assay, haematology and eosinophil counts were detected in blood. Participating families filled in a questionnaire and studied children were clinically evaluated by paediatricians. Results: Anti-Toxocara spp. antibodies were detected in 14.3% of children. The seroprevalence in the schools studied ranged from 4.4% to 24.1%. Statistical associations with eosinophilia, decreased visual acuity, eyestrain, headache and paleness were found. Significant risk factors were contact with dogs, playing with dogs and playing with soil. Conclusions: The identification of risk factors and their association with infection suggest that the infection is a problem in the municipalities studied, so screening for toxocariasis in school children should be recommended.

Frequency of anti-Toxocara antibodies in broiler chickens in southern Brazil / Frequência de anticorpos anti-Toxocara em frangos de corte no Sul do Brasil

Abstract The aim of this study was to evaluate the presence of anti-Toxocara antibodies in naturally infected broiler chickens (n = 189) from the state of Paraná, southern Brazil. The chickens were reared in a semi-intensive system by small family farmers (n = 7). An enzyme-linked immunosorbent assay (ELISA) was performed to detect the presence of anti- Toxocara spp. IgY after serum adsorption with Ascaridia galli antigens. An overall seroprevalence of 67.7% (128/189; 95% CI = 61.1-74.4) was observed. The frequency of positive animals by farm ranged from 29.6% to 100%. The optical density and reactivity index values observed in ELISA test indicated the possible chronicity of infection of the evaluated chickens. Associations between the presence of antibodies and the area where the chickens were reared (p = 0.382) or the population density of dogs on the farm (p = 0.785) were not observed. This study shows a high prevalence of Toxocara spp. antibodies in broiler chickens reared in semi-intensive systems and provides evidence that chickens are a good indicator of environmental contamination by larva migrans agents. Further studies are necessary to assess the risk factors associated with poultry infection and the likelihood of toxocariasis transmission to humans via the ingestion of free-range chicken meat.

Resumo A finalidade do presente estudo foi avaliar a presença de anticorpos anti- Toxocara, em frangos de corte naturalmente infectados (n = 189), no Norte do Paraná, Sul do Brasil. Os frangos foram criados em sistema semi-intensivo, em pequenas propriedades rurais (n = 7). Os testes sorológicos foram realizados pela técnica de ELISA, para detecção de anticorpos IgY (IgG), com pré-adsorção do soro com antígenos de Ascaridia galli. Foi observada uma prevalência de 67,7% (128/189; IC 95% = 61,1-74,4). A frequência de animais soropositivos por propriedade variou de 29,6% a 100%. Os valores da Densidade Ótica e do Índice de Reatividade observados no teste de ELISA indicaram uma possível cronicidade de infecção dos frangos avaliados. Não foi observada correlação entre a positividade dos animais, quando comparada a área (p = 0,382) e a densidade populacional de cães por propriedade (p = 0,785). O presente estudo verificou uma alta prevalência de anticorpos anti-Toxocara em frangos de corte criados em sistema semi-intensivo e oferece dados que apontam esses animais como bons indicadores de contaminação ambiental por agentes de larva migrans . Estudos futuros são necessários para avaliar os fatores de risco associados e a possibilidade da transmissão de toxocaríase ao ser humano pela ingestão de carne de frango.