Immune response to chronic Toxocara canis infection in a mice model.

AIMS: The zoonotic nematode Toxocara canis causes larva migrans syndrome that induces an immune response characterized by the production of antibodies and eosinophilia. A Th2 polarization has been associated with the infection, but there are still details of the cellular and humoral immune response that need to be described. Thus, the aim of this study was to describe the systemic host immune response to T canis chronic infection in a mouse model. METHODS AND RESULTS: BALB/c mice were inoculated once with 500 T canis embryonated eggs, per os. After 49 days, the amounts of larval found in brain and muscle tissues were statistically two and four times higher, respectively, than the amounts found in lung, liver, kidney or heart tissues. Splenic proportions of F4/80+ cells, as well as B, cytotoxic T and CD4+ Foxp3+ lymphocytes, were statistically higher (P ≤ .05, P ≤ .01, P ≤ .001 and P ≤ .001, respectively) as compared with control mice. In lymph nodes, some of these proportions changed, with the exception of F4/80+ cells. IgG1 levels in infected mice sera were increased. IL-4, IL-10 and VEGF levels were statistically higher in spleen (P ≤ .05, all) and sera (P ≤ .01, P ≤ .05 and P ≤ .05, respectively) in the infected mice. Also, in infected animals, IL-5 serum levels were increased (P ≤ .01). CONCLUSION: These results suggest that T canis chronic infection in BALB/c mice results in a type 2 response with an incipient regulatory response.

Frequency of Toxocara canis antibodies in Mexican paediatric patients with epilepsy.

The relationship between epilepsy and the presence of visceral larva migrans caused by Toxocara canis in Mexican children remains uncertain; however, this relationship needs to be elucidated because these parasite larvae can invade the human central nervous system. Accordingly, this study aimed to determine the frequency and specificity of anti-T. canis antibodies in the sera of children with epilepsy to determine the relationship between this parasite and epilepsy. The sera samples of 214 children were examined: 111 children diagnosed with epilepsy and 103 clinically healthy children without neurological disorders. In the sera of each group, the presence and specificity of anti-T. canis and anti-Ascaris lumbricoides antibodies, as well as the cross-reactivity between them, were assessed using enzyme-linked immunosorbent assay and Western blotting analysis. Among the children with epilepsy, 25.2% exhibited seropositivity to T. canis. Cross-reactivity against the A. lumbricoides antigen was present in 46.8% of the children with epilepsy, whereas 11.7% of the children with epilepsy and anti-T. canis antibodies did not exhibit cross-reactivity against this antigen. The Western blotting analysis of the sera from the children with epilepsy demonstrated the presence of T. canis proteins, with molecular weights of 24, 35, 55, 70, 120 and 210 kDa, and A lumbricoides proteins with molecular weights of 70, 80 and 110 kDa. Our results revealed the presence of anti-T. canis antibodies in the children with epilepsy; furthermore, cross-reactivity tests with A. lumbricoides showed the importance of the presence of anti-T. canis antibodies in revealing the relationship between this parasite and epilepsy in children.

Incidence of Ascaris suum-specific antibodies in Austrian patients with suspected larva migrans visceralis (VLM) syndrome.

The pig roundworm, Ascaris suum, is commonly found in domestic pigs all over the world. The transmission to humans takes place by ingestion of infective A. suum eggs present in soil because pig manure is widely used as fertilizer. The possible role of A. suum in the human visceral larva migrans (VLM) syndrome has been discussed controversially during past decades, even though various case reports, particularly from Japan document pulmonal, hepatic and even cerebral symptoms caused by migrating A. suum larvae after ingestion of infected row meat (liver) or contaminated vegetables. We examined 4481 sera by A. suum immunoblot (As-IB) and 5301 sera by Toxocara-ELISA from patients with symptoms associated with the VLM syndrome during three consecutive years (2012-2014). The incidence of A. suum-specific antibodies was 13.2 %, the incidence of T. canis specific antibodies 12.9 % and from a part of the As-IB positive sera (n = 417) additional Toxocara serology was performed to demonstrate the specificity of our tests. Only 56 out of the 417 (13.4 %) sera showed antibodies to both helminth species demonstrating that double infections exist. Interestingly the age distribution of the patients showed that 2.8 % of the Ascaris-positive patients were younger than 21 years, while in the Toxocara-positive group 13.4 % were <21 years. These results are in accordance with a Dutch study suspecting different ways of transmission as cause for this interesting age distribution. Due to the fact that large amounts of untreated pig manure are used as fertilizer and that the expulsion of adult A. suum worms causing intestinal ascariosis is extremely rare in Central European countries, the zoonotic potential of A. suum is considerably underestimated. We suggest that the performance of reliable immunoserological tests, in all industrialized countries where pigs are raised and their manure is used as fertilizer, could help to assess the actual potential of A. suum as causative agent of the VLM syndrome in humans.

HEPATIC VISCERAL LARVA MIGRANS DUE TO TOXOCARA CANIS IN A 72-YEAR-OLD MAN.

Hepatic toxocariasis is visceral larva migrans caused by Toxocara. We report a case of hepatic toxocariasis detected incidentally during a health checkup. The patient had elevated levels of eosinophils, total IgE, and anti-Toxocara IgG antibodies. On contrast-enhanced computed tomography (CT) imaging he had a single, 2.16 cm, oval, ill-defined, low-attenuation hepatic nodule which was best appreciated during the portal venous phase of the scan. Clinicians should consider hepatic toxocariasis as a possible diagnosis in any individual who presents with eosinophilia of unknown etiology and an ill-defined hepatic lesion on CT imaging.

Immunoblot for the detection of Ascaris suum-specific antibodies in patients with visceral larva migrans (VLM) syndrome.

Visceral larva migrans (VLM) syndrome caused by Toxocara canis larvae was first described in the 1950s. The role of other nematode larvae, i.e. the pig roundworm Ascaris suum as a causative agent of visceral larva migrans-associated symptoms like general malaise, cough, liver dysfunction, hypereosinophilia with hepatomegaly and/or pneumonia, was discussed controversially during the last decades. Recent serological screening studies for specific A. suum antibodies carried out in the Netherlands and Sweden yielded remarkable high seroprevalences, while a number of case reports from Japan report pulmonal, hepatic and cerebral symptoms caused by A. suum larvae after ingestion of infected raw meat (liver) or contaminated vegetables. We present here a sensitive and specific larval excretory-secretory (E/S) antigen-based immunoblot (As-IB) for the serodiagnosis of A. suum-infected patients suffering from symptoms associated to the VLM syndrome. In total, 34 sera from patients with hypereosinophilia and other clinical symptoms associated to the VLM syndrome tested negative for Toxocara sp. antibodies but positive in our newly established As-IB, 30 sera from healthy volunteers, 53 sera from patients with clinically and serologically confirmed toxocarosis and other helminthoses as well as 3 sera from patients with intestinal ascariosis due to Ascaris lumbricoides were included in the study. When evaluated with 30 sera from healthy volunteers and 53 sera from patients suffering from different helminthoses, the calculated specificity of our new As-IB is 95%. Problems hampering the establishment of simple serological screening tests for specific A. suum antibodies, like extensive antigenic similarities between the nematodes Ascaris and Toxocara or the absence of suitable experimental animals, are discussed. We assume that specific serological testing for antibodies of A. suum is very important for the treatment of individual patients on one hand and seroepidemiological investigations will help to clarify routes of transmission on the other hand. Further studies will be necessary to learn more about the extent of A. suum as a causative agent of the VLM syndrome and the role of pigs and their manure as the main source of human Ascaris infections in Austria and other industrialized countries.

Visceral larva migrans syndrome: analysis of serum cytokine levels in children with hepatic lesions confirmed in radiological findings.

Human toxocariasis is a helminth zoonosis resulting from accidental infection of humans by the roundworms Toxocara canis (T. canis) and cati (T. cati). The infection occurs in five forms: systemic (VLM), ocular, neurological, covert and asymptomatic. The aim of this study was to characterize the radiological and immunological findings in hepatic inflammation during the course of systemic infection by Toxocara sp. in children. Fifteen children, 2 to 17 years of age, with serological diagnosis of T. canis infection underwent abdominal ultrasonography and computer tomography (CT). Eosinophil counts, immunoglobulin E titres, interleukins IL-1α, IL-4, Il-6, IL-10 and interferon gamma were measured for all patients. Abdominal ultrasound revealed multiple hypoechoic areas in the livers of all patients. On the CT images, the hepatic lesions were seen as multiple, ill-defined, oval low-attenuating nodules that measured 6 to 9 millimetres in diameter. The nodules were usually best seen in the portal venous phase and were not seen on arterial-phase images. Significant intergroup differences were observed in the concentrations of IL-1α, IL-4, IL-6 and IL-10. The level of IFN-γ was not significantly elevated in patient sera relative to controls. The analysis shows that the production of anti-inflammatory cytokines is insufficient for granuloma formation in children presenting liver lesions in the course of VLM.

Unusual panuveitis in a child: toxocariasis associated with ocular myiasis.

Most panuveitis in children are caused by infectious agents. A detailed clinical history and clinical examination are helpful in the diagnosis, but specific techniques are sometimes required to identify the causing specimen. We report the first published case of panuveitis in a child caused by simultaneous ocular infection by Toxocara canis and a fly larva and the innovative use of immunodiffusion technique in the vitreous for the diagnosis.

Alteration of cytokine production during visceral larva migrans by Toxascaris leonina in mice.

To determine alteration of immune responses during visceral larva migrans (VLM) caused by Toxascaris leonina at several time points, we experimentally infected mice with embryonated eggs of T. leonina and measured T-helper (Th) cell-related serial cytokine production after infection. At day 5 post infection (PI), most larvae were detected from the lungs, spleen, intestine, and muscle. Expression of thymic stromal lymphopoietin (TSLP) and CCL11 (eotaxin) showed a significant increase in most infected organs, except the intestine. However, expression of the CXCL1 (Gro-α) gene was most highly enhanced in the intestine at day 14 PI. Th1-related cytokine secretion of splenocytes showed increases at day 28 PI, and the level showed a decrease at day 42 PI. Th2-related cytokine secretion of splenocytes also showed an increase after infection; in particular, IL-5 level showed a significant increase at day 14 PI, and the level showed a decrease at day 28 PI. However, levels of Th17-related cytokines, IL-6 and IL-17A, showed gradual increases until day 42 PI. In conclusion, Th1, Th2, and Th17-related cytokine production might be important in immune responses against T. leonina VLM in experimental mice.

Factors affecting disease manifestation of toxocarosis in humans: genetics and environment.

Toxocara canis is regarded as the main cause of human toxocarosis but the relative contribution of T. cati is probably underestimated; serological and other diagnostic methods used in most studies of this zoonotic disease do not distinguish between the two parasites. The definitive hosts for T. canis are caniidae. Pups generally have higher infection rates than adult animals and are a major source of eggs in the environment. Humans usually acquire T. canis infection by accidental ingestion of embryonated eggs or encapsulated larvae from the environment or contaminated food, such infections may lead to visceral larva migrans (VLM), ocular larva migrans (OLM) or covert toxocarosis (CT). Although a mixed Th1- and Th2-mediated immunological response, particularly with high levels of IgE and eosinophilia is observed, the underlying mechanisms of molecular and immunopathogenesis for the development of the symptomatic syndromes of VLM, OLM, or of asymptomatic CT are largely unclear. Studies have indicated that immunological defences against various infectious diseases may be highly influenced by complex interactions of environmental and host genetic factors e.g. MHC class I and II, also known as human leucocyte antigen (HLA). Toxocara spp. infections are associated with a polarized CD4(+) Th2 response with high IgE levels and eosinophilia, mediated mainly by HLA class II molecules. Associations have been made between HLA class II and pathological severity and host genetic effects on exposure to infection. Recent research suggests Foxp3(+) CD4(+)CD25(+)-expressing T regulatory (Treg) cells play a role in regulation of the immunopathology of granulomas in experimental toxocaral granulomatous hepatitis and in enhanced expression of TGF-ß1, which is an important factor for the local survival and function of Treg observed during T. canis invasion in the mouse small intestine, liver, muscle, and brain. Since the potential susceptibility loci HLA class II molecules, are considered involved in the regulation of a Th2-dominant immunity which is highly controlled by Foxp3(+) CD4(+)CD25(+) Treg cells by stimulation through TGF-ß1, which thus provides a beneficial environment to T. canis larvae but severe injuries to local organs. However, TGF-ß1 variant Leu10Pro known to be involved in disease severity warrants further elucidation as this too may have a role in the severity of human toxocarosis. Exploration of TGF-ß1 polymorphism, Foxp3(+) CD4(+)CD25(+) Treg cells, and MHC polymorphisms may allow insight into the contribution made by environmental and genetic factors in influencing disease syndrome type and severity in humans with toxocarosis.

Alteration of Cytokine Production during Visceral Larva Migrans by Toxascaris leonina in Mice

To determine alteration of immune responses during visceral larva migrans (VLM) caused by Toxascaris leonina at several time points, we experimentally infected mice with embryonated eggs of T. leonina and measured T-helper (Th) cell-related serial cytokine production after infection. At day 5 post infection (PI), most larvae were detected from the lungs, spleen, intestine, and muscle. Expression of thymic stromal lymphopoietin (TSLP) and CCL11 (eotaxin) showed a significant increase in most infected organs, except the intestine. However, expression of the CXCL1 (Gro-alpha) gene was most highly enhanced in the intestine at day 14 PI. Th1-related cytokine secretion of splenocytes showed increases at day 28 PI, and the level showed a decrease at day 42 PI. Th2-related cytokine secretion of splenocytes also showed an increase after infection; in particular, IL-5 level showed a significant increase at day 14 PI, and the level showed a decrease at day 28 PI. However, levels of Th17-related cytokines, IL-6 and IL-17A, showed gradual increases until day 42 PI. In conclusion, Th1, Th2, and Th17-related cytokine production might be important in immune responses against T. leonina VLM in experimental mice.

Synthesis, antigenicity against human sera and structure-activity relationships of carbohydrate moieties from Toxocara larvae and their analogues.

Stereocontrolled syntheses of biotin-labeled oligosaccharide portions containing the Galß1-3GalNAc core of the TES-glycoprotein antigen obtained from larvae of the parasite Toxocara and their analogues have been accomplished. Trisaccharides Fuc2Meα1-2Gal4Meß1-3GalNAcα1-OR (A), Fucα1-2Gal4Meß1-3GalNAcα1-OR (B), Fuc2Meα1-2Galß1-3GalNAcα1-OR (C), Fucα1-2Galß1-3GalNAcα1-OR (D) and a disaccharide Fuc2Meα1-2Gal4Meß1-OR (E) (R = biotinylated probe) were synthesized by block synthesis using 5-(methoxycarbonyl)pentyl-2,3,4,6-tetra-O-acetyl-ß-D-galactopyranosyl-(1-->3)-2-azide-4-O-benzyl-2-deoxy-α-D-galactopyranoside as a common glycosyl acceptor. We examined the antigenicity of these five oligosaccharides by enzyme linked immunosorbent assay (ELISA). Our results demonstrate that the O-methyl groups in these oligosaccharides are important for their antigenicity and the biotinylated oligosaccharides A, B, C and E have high serodiagnostic potential to detect infections caused by Toxocara larvae.

Seroprevalence and risk factors for canine toxocariasis by detection of specific IgG as a marker of infection in dogs from Salvador, Brazil.

Toxocara canis is a highly prevalent worldwide canine nematode responsible for enzootic and zoonotic infections. It is considered to be one of the main agents of human visceral and ocular larva migrans. False negative diagnosis may occur because adult infected dogs with "dormant" larvae may have negative fecal test results since they usually do not shed parasite eggs in their stools. During pregnancy, the larvae become active and infect the offspring through the placenta. A serological test can distinguish infected animals, thus increasing the accuracy of the diagnosis for epidemiological studies and prophylactic purposes. In the present work a serological investigation was carried out to study the risk factors for the acquisition of this infection in 301 dogs inhabiting the city of Salvador, northeast Brazil. A validated questionnaire was applied to the donors and caretakers to assess animal management practices. All dogs were submitted to clinical evaluation and blood collection. Serum samples were analyzed for IgG antibodies against excretory-secretory products of T. canis larvae, used as antigens, by indirect ELISA. The overall seroprevalence of anti-T. canis IgG antibodies was 82.7%. Risk factors for T. canis infection included sex, area of origin within the city, homemade leftover food intake, failure to receive regular vaccination against infectious diseases and lack of preventive anti-helminthic treatment. Most of these risk factors suggest a lack of veterinary care and poverty. The high frequency of seropositivity found for toxocariasis in dogs suggests that results based on parasitological fecal examination could underestimate the actual prevalence of the infection.

Toxocariasis: visceral larva migrans in children.

OBJECTIVES: To present a detailed investigation of risk factors, symptoms, and laboratory and imaging tests that may be useful to establish the clinical laboratory diagnosis of visceral larva migrans (VLM) in children, demonstrating the importance of diagnosis and treatment to prevent complications in the eyes, liver, and other organs. SOURCES: Literature review using the MEDLINE and LILACS (1952-2009) databases, selecting the most recent and representative articles on the topic. SUMMARY OF THE FINDINGS: VLM is an infectious disease with non-specific clinical presentation, whose transmission is related to contact with dogs, especially puppies, and which may progress to late systemic complications in vital organs such as the eyes and the central nervous system. IgG (ELISA) anti-T. canis can be used to establish the laboratory diagnosis. Higher cutoff points suggest recent illness and lower cutoff points demonstrate mild infection or infection in remission. Therapeutic response may be assessed by means of eosinophil blood cell count. The present article provides the pediatrician with updated information regarding VLM, a disease of high prevalence worldwide and in Brazil. CONCLUSIONS: The diagnosis of VLM depends mainly on the presence of dogs in the child's household, associated with ELISA (IgG anti-T. canis), using excretory-secretory antigens of Toxocara canis. Prospective studies are warranted to assess the best drug therapy. Prevention is the most important strategy because of the high prevalence of T. canis in urban areas.

Toxocaríase: larva migrans visceral em crianças e adolescentes / Toxocariasis: visceral larva migrans in children

OBJETIVOS: Apresentar investigação detalhada de fatores de risco, sintomatologia, exames laboratoriais e de imagem que possam contribuir para o diagnóstico clínico-laboratorial da larva migrans visceral (LMV) em crianças e mostrar a importância do diagnóstico e do tratamento para evitar complicações oculares, hepáticas e em outros órgãos. FONTES DOS DADOS: Revisão de literatura utilizando os bancos de dados MEDLINE e LILACS (1952-2009), selecionando os artigos mais atuais e representativos do tema. SÍNTESE DOS DADOS: LMV é uma doença infecciosa de apresentação clínica inespecífica cuja transmissão está relacionada ao contato com cães, principalmente filhotes, podendo evoluir com complicações sistêmicas tardias em órgãos vitais como o olho e sistema nervoso central. Para diagnóstico laboratorial, pode ser utilizado IgG (ELISA) anti-Toxocara canis, cujos pontos de corte mais elevados sugerem doença recente e, os mais baixos, infecção leve ou em resolução. A resposta terapêutica pode ser avaliada por meio da contagem de eosinófilos no sangue. Esse artigo atualiza o pediatra em relação à LMV, doença de alta prevalência no mundo e no Brasil. CONCLUSÕES: O diagnóstico de LMV depende principalmente da epidemiologia da presença de cães no domicílio da criança, associada ao ELISA (IgG para T. canis), utilizando antígenos Toxocara de excreção e secreção. São necessários estudos prospectivos para avaliar a melhor droga na terapêutica. A prevenção é a estratégia mais importante devido à alta prevalência de T. canis na região urbana.

OBJECTIVES: To present a detailed investigation of risk factors, symptoms, and laboratory and imaging tests that may be useful to establish the clinical laboratory diagnosis of visceral larva migrans (VLM) in children, demonstrating the importance of diagnosis and treatment to prevent complications in the eyes, liver, and other organs. SOURCES: Literature review using the MEDLINE and LILACS (1952-2009) databases, selecting the most recent and representative articles on the topic. SUMMARY OF THE FINDINGS: VLM is an infectious disease with non-specific clinical presentation, whose transmission is related to contact with dogs, especially puppies, and which may progress to late systemic complications in vital organs such as the eyes and the central nervous system. IgG (ELISA) anti-T. canis can be used to establish the laboratory diagnosis. Higher cutoff points suggest recent illness and lower cutoff points demonstrate mild infection or infection in remission. Therapeutic response may be assessed by means of eosinophil blood cell count. The present article provides the pediatrician with updated information regarding VLM, a disease of high prevalence worldwide and in Brazil. CONCLUSIONS: The diagnosis of VLM depends mainly on the presence of dogs in the child's household, associated with ELISA (IgG anti-T. canis), using excretory-secretory antigens of Toxocara canis. Prospective studies are warranted to assess the best drug therapy. Prevention is the most important strategy because of the high prevalence of T. canis in urban areas.

[Analysis of children with a presumptive diagnosis of toxocariasis in Santa Fe, Argentina]. / Estudio en niños con diagnóstico presuntivo de toxocariasis en Santa Fe, Argentina.

Human toxocariasis is a parasitic disease found worldwide. The most important etiological agent is Toxocara canis, a dog parasite. Humans are infected by the ingestion of their eggs; the eggs hatch in the small intestine and the larvae migrate through the capillaries, taking up residence in different tissues. Clinical manifestations are associated with mechanical and/or reaction damage caused by these parasites larvae. Clinical diagnosis is difficult. The method applied in this work is the demonstration of antibodies against the helminth in the blood of children, target host population of this parasitic disease. An ELISA test was performed using T. canis larval excretory-secretory products as antigen. A total of 100 children presumptively diagnosed of toxocariasis that had been derived from different services of the Regional Children's Hospital for complementary studies, were included in the analysis. The test detected two different populations: infected (59) and non-infected (41). The statistical analysis showed a non significant association between infection and sex (p = 0.279). Infected subjects tended to be older than the non infected (p = 0.009). Eosinophilia was detected in 100% of seropositive children and in 85.2% of the seronegative. There was no significant association between infection and leucocytosis (p = 0.950). The association of these two parameters was significantly higher among infected patients (R = 0.918). Respiratory symptoms and signs were more frequently detected in the positive population (p = 0.05). Dogs tenancy was as frequent among infected as in the non infected homes (p = 0.53). According to these results, prevention, early diagnosis and opportune treatment for toxocariasis should be considered as priority health activities in this region.

Estudio en niños con diagnóstico presuntivo de toxocariasis en Santa Fe, Argentina / Analysis of children with a presumptive diagnosis of toxocariasis in Santa Fe, Argentina

La toxocariasis humana es una parasitosis de amplia distribución en el mundo, cuyo agente etiológico más importante es el Toxocara canis, parásito del perro. El hombre adquiere esta zoonosis mediante la ingesta de huevos infectivos; en el intestino delgado desarticulan sus envolturas y las larvas se liberan atravesando la mucosa, ubicándose en diversos tejidos. Los niños son la población de mayor riesgo. El diagnostico clínico es dificultoso. El test de ELISA usando antígenos de excreción-secreción de la larva, es la técnica de elección. Se estudiaron por esta técnica inmunoserológica 100 niños con diagnóstico presuntivo de toxocariasis y se revisaron posteriormente sus historias clínicas de Hospital. La técnica de diagnóstico fue estandarizada y validada en el laboratorio. Su aplicación permitió identificar dos poblaciones de niños: infectados (59) y no infectados (41). La eosinofilia fue más frecuente en la población infectada (100% vs. 85.2%, p = 0.017); no así la leucocitosis (p = 0.950). La fuerza de asociación de ambos parámetros fue mayor en la población positiva (R = 0.918). La dificultad respiratoria se presentó más frecuentemente en pacientes con ELISA positiva, considerados como infectados (p = 0.05). La edad promedio de los positivos fue significativamente mayor que la de los negativos (p = 0.009). Se halló eosinofilia en el 100% de los infectados y en el 85.2% de los no infectados. La tenencia de canes en los domicilios no fue significativamente mayor entre los casos positivos que entre los negativos (p = 0.53). Sería necesario investigar esta enfermedad en niños consultantes con sospecha clínica, y promover las medidas de prevención, diagnóstico temprano y su correcto tratamiento.

Human toxocariasis is a parasitic disease found worldwide. The most important etiological agent is Toxocara canis, a dog parasite. Humans are infected by the ingestion of their eggs; the eggs hatch in the small intestine and the larvae migrate through the capillaries, taking up residence in different tissues. Clinical manifestations are associated with mechanical and/or reaction damage caused by these parasites larvae. Clinical diagnosis is difficult. The method applied in this work is the demonstration of antibodies against the helminth in the blood of children, target host population of this parasitic disease. An ELISA test was performed using T. canis larval excretory-secretory products as antigen. A total of 100 children presumptively diagnosed of toxocariasis that had been derived from different services of the Regional Children’s Hospital for complementary studies, were included in the analysis. The test detected two different populations: infected (59) and non-infected (41). The statistical analysis showed a non significant association between infection and sex (p = 0.279). Infected subjects tended to be older than the non infected (p = 0.009). Eosinophilia was detected in 100% of seropositive children and in 85.2% of the seronegative. There was no significant association between infection and leucocytosis ( = 0.950). The association of these two parameters was significantly higher among infected patients (R = 0.918). Respiratory symptoms and signs were more frequently detected in the positive population (p = 0.05). Dogs tenancy was as frequent among infected as in the non infected homes (p = 0.53). According to these results, prevention, early diagnosis and opportune treatment for toxocariasis should be considered as prioritary health activities in this region.

Prevalence of Toxocara-induced liver granulomas, detected by immunohistochemistry, in a series of autopsies at a Children's Reference Hospital in Vitoria, ES, Brazil.

The aim of this investigation was to study the frequency of visceral larva migrans (VLM) granulomas in autopsies at a Children's Reference Hospital in Vitoria, ES Brazil, where anti-Toxocara antibodies are frequently detected in the serum of children admitted at the hospital. Two liver fragments from 310 autopsies of children aged between 1 and 15 years were paraffin embedded, and sections were stained with hematoxylin and eosin and submitted to detection of Toxocara antigens using a rabbit anti-Toxocara serum. Among the 24 cases with granulomatous lesions, ten had eosinophil-rich granulomas positively stained with the anti-Toxocara serum. Some were typical epithelioid granulomas, with a positive reaction in multinucleated giant cells, epithelioid cells, or necrotic debris. The results showed that VLM granulomas are the most frequent granulomatous hepatitis in children in our county. This agrees with the high prevalence of anti-Toxocara antibodies in the serum of children admitted to the Children's Reference Hospital. The 3.2% frequency of liver VLM granulomas in autopsies is less than the 30-39% frequency of positive serology in these children, probably reflecting the low larval burden in infected children.

A familial case of visceral larva migrans after ingestion of raw chicken livers: appearance of specific antibody in bronchoalveolar lavage fluid of the patients.

We report a familial case of visceral larva migrans (VLM) caused by Toxocara canis larvae. Patient 1 was a 45-year-old man who presented to our university hospital complaining of mild fever, general fatigue, and headache. Patient 2 was a 71-year-old man and was the father of Patient 1; he presented complaining of cough and hyper-viscous white sputum. Laboratory data from both patients showed extensive eosinophilia, their chest X-ray findings revealed multiple pulmonary infiltrates, and their bronchoalveolar lavage fluid (BALF) showed an elevated eosinophil count. The diagnosis of VLM was made based on a positive result in a serological test using T. canis larval excretory-secretory both in the serum and BALF. T. canis larvae were identified in meat that was prepared from chicken taken from the same source as that ingested. This is the first report to identify antibodies in BALF in patients with VLM.

Sero-epidemiology of Toxocara canis infection among aboriginal schoolchildren in the mountainous areas of north-eastern Taiwan.

A sero-epidemiological study of Toxocara canis infection was conducted among Atayal schoolchildren (aged 7-12 years) residing in the mountainous areas of north-eastern Taiwan. The 73 children investigated were each checked for anti-Toxocara IgG, in ELISA based on the larval excretory-secretory antigens of T. canis larvae. A short, self-administered questionnaire was then used to collect relevant information from each subject, including data on the keeping of dogs, playing in soil, eating raw vegetables, and whether the subjects normally washed their hands before eating. Once the seropositive children had been identified, odds ratios (OR), with their corresponding 95% confidence intervals (CI) and P-values, were calculated for each potential risk factor. When diluted 1:64, sera from 42 (57.5%) of the children gave a positive result in the ELISA, indicating that these 42 children were seropositive for T. canis infection. Seropositivity did not appear to be associated with the age or gender of the subject, the eating of raw vegetables, or the regular failure to wash hands prior to a meal. Compared with the other subjects, however, those who admitted living in a household where dogs were kept (OR = 3.79; CI = 1.23-11.69; P = 0.02) or playing in soil (OR = 3.00; CI = 1.10-8.16; P = 0.03) appeared at increased risk of seropositivity.

[Toxocariasis in children from a subtropical region]. / Toxocariosis en niños de una region subtropical.

Toxocariasis is present worldwide but people living in areas with sanitary deficiencies are considered at the highest risk of infection, particularly children. The aim of this work was to know clinical and immunological aspects of infantile toxocariasis in a subtropical region in Argentina. For this purpose, 182 children of both sexes, 0-16 years old and with eosinophilia higher than 10%, living in Resistencia City (Northeast Argentina) were studied. Clinical examination, personal and epidemiological data recording, parasitological fecal examination and dosage of Toxocara canis IgG and IgM levels by EIE were performed; all positive sera were confirmed by Western Blot. Out of 182 children, 122 were positive for T. canis-IgG (67.0%); 28.8% lack of potable drinking water at home, 58.8% lack of sewerage facilities, 91.1% referred a close contact with dogs or cats, 30.0% had a history of geophagia and 86.7% lived along streets without pavement. The clinical forms of the infection were: 77.8% asymptomatic, 6.7% ocular larva migrans and 15.5% visceral larva migrans. In 22 children the serological follow up until 18 months after treatment showed 10 children without change in IgG levels, in 11 it decreased but remained high, and in one it increased. There were 19 children with high levels of T. canis-IgM; in 8 it decreased along treatment, in one it remained stable and 10 of them became negative. There was one child considered as a re-infection case. Results highlight the importance that health authorities should assign to this infection in regions with sanitary deficiencies, where toxocariasis is usually not recognized as a relevant public health problem.