Toxocariasis en niños: análisis de 85 casos en un hospital pediátrico de Argentina / Toxocariasis in children: analysis of 85 cases in a paediatric hospital in Argentina

INTRODUCCIÓN: La toxocariasis es una enfermedad parasitaria ampliamente distribuida. Las formas clínicas descritas son la asintomática (TA), larva migrans visceral (LMV), larva migrans ocular (LMO) y encubierta (TE). OBJETIVOS: Describir las características clínicas, de laboratorio, evolución y tratamiento de los casos y comparar las diversas formas clínicas de presentación. PACIENTES Y MÉTODOS: Análisis retrospectivo de todos los pacientes pediátricos con diagnóstico de toxocariasis atendidos en el Servicio de Infectología del Hospital General de Niños Pedro de Elizalde entre 2012 y 2019. RESULTADOS: Se incluyeron 85 pacientes. El 63,5 % fueron varones y la mediana de edad fue de 60 meses. Cuarenta y nueve pacientes presentaron TA, 14 LMV, 15 LMO y 7 TE. Los pacientes con LMV presentaron menor edad y recuento de eosinófilos más altos. Todos los casos de LMO presentaron mal pronóstico visual. Se indicó tratamiento con albendazol en todos los casos de LMV, en los casos activos de LMO, en 4 TE y en 3 TA. CONCLUSIÓN: Este estudio representa uno de los más grandes llevados a cabo en el país. Todas las formas clínicas excepto las LMO tuvieron buena evolución. Resulta fundamental enfatizar en la prevención y en el diagnóstico precoz de la enfermedad para instaurar de manera oportuna el tratamiento y evitar secuelas.

BACKGROUND: Toxocariasis is a widely spread parasitic disease. The most frequent clinical form is asymptomatic (AT) although it may present with visceral larva migrans (VLM), ocular larva migrans (OLM) or covert (TE) involvement. Aims: To describe the clinical presentation, laboratory, evolution and treatment characteristics of the cases and to compare the various clinical forms of presentation. PATIENTS AND METHODS: Retrospective analysis of all children diagnosed with toxocariasis attended at the Infectology Service of the Pedro de Elizalde Children's General Hospital between 2012-2019. RESULTS: We included 85 patients. 63.5% were males and the median age was 60 months. 49 patients presented AT, 14 VLM, 15 OLM and 7 TE. Children with LMV had lower age and higher eosinophil count. All the cases of OLM evolved with a poor visual prognosis. Treatment with albendazole was indicated in all cases of LMV, in active cases of LMO, in 4 TE and in 3 AT. CONCLUSION: This study represents one of the largest conducted in our country. The ocular forms had bad prognosis, while the visceral and covert forms had good evolution. It is essential to emphasize the prevention and early diagnosis of the disease in order to establish timely treatment and avoid sequelae.

Análise epistemológica dos conhecimentos científicos sobre Toxocara sp. com ênfase na infecção humana / Epistemological analysis of the scientific knowledge about Toxocara sp. with the emphasis on human infection

Resumo Este artigo objetivou analisar a evolução do conhecimento sobre Toxocara sp. em seu aspecto zoonótico por meio de dados científicos entre os anos de 1996 a 2015 utilizando a epistemologia como ferramenta. A análise epistemológica da evolução do conhecimento sobre o aspecto zoonótico de Toxocara sp. no Brasil demonstrou que, de uma maneira geral, foram agregadas poucas novas informações as quais tiveram, ao longo do período estudado, absorção lenta, descontínua, e não foram inseridas na realidade social do ponto de vista de Saúde Pública.

Abstract The scope of this article was to analyze the evolution of knowledge about Toxocara sp. from a zoonotic point of view by means of scientific data published between the years 1996 and 2015 using epistemology as a tool. The epistemological analysis of the evolution of knowledge on the zoonotic aspect of Toxocara sp. in Brazil revealed that, in general, little new information was added which had, over the period studied, slow and discontinuous absorption, and was not incorporated in the social reality from the standpoint of public health.

Clinical and laboratory characteristics of patients with toxocariasis encountered at a tertiary care centre in North India

Toxocariasis is a neglected soil-transmitted helminthic infection caused by either Toxocara canis or Toxocara cati where humans get infected by accidental ingestion of embryonated eggs, and the definitive hosts are dogs and cats. This study aims to analyse the clinical and laboratory characteristics of Toxocara-infected patients and assessment of response to standard treatment with review of literature. The clinical details of patients with Toxocara serology positive for IgG antibodies by ELISA in 5 years (2013–2017) were retrospectively analysed. A total of 29 patients with clinical features and serology suggestive of Toxocara infection were evaluated. A complete history of 14 patients was available for the analysis. Majority (13/14; 96.5%) of cases were children <15 years, males (79%) and belonged to lower socioeconomic status (64.3%). The most common clinical presentation was fever (78.5%) with respiratory symptoms (57%) followed by gastrointestinal features (35.7%). All the patients had eosinophilia (range 8.3%–85%) and raised total IgE levels. Toxocariasis is more common in children, and the true prevalence may be underestimated. In endemic areas, Toxocara workup should be considered in patients with eosinophilia presenting with respiratory and gastrointestinal features.

Larva migrans visceral. Presentación de un caso / Visceral larva migrans. Report of a case

RESUMEN La larva migrans visceral es una enfermedad que se produce al ingerir huevos infectantes de nematodos parásitos de gatos y perros (Toxocaracanis y Toxocaracati); los cuales eclosionan en el intestino del hombre y las larvas se distribuyen en todo el organismo, principalmente hígado, pulmón, corazón y cerebro. Las larvas en su migración dejan trazos de hemorragias, necrosis y células inflamatorias; algunas son destruidas por la respuesta inmune del huésped y otras forman granulomas eosinofílicos. Los síntomas dependen del tejido u órgano afectado, de la intensidad de la infección y del grado de la respuesta inmunológica inducida. Se presenta un caso del sexo masculino de 72 años que ingresa en el Servicio de Medicina del Hospital Militar Docente “Dr. Mario Muñoz Monroy”, de Matanzas, por cuadro de fiebre, diarreas, tos seca, astenia, anorexia y pérdida de peso al que se le diagnosticó larva migrans visceral. Por lo atípico de la edad del paciente y la complejidad del diagnóstico decidimos presentar este caso (AU).

ABSTRACT Visceral larva migrans is a disease produced after the ingestion of infectant eggs of cat´s and dog´s nematode parasites (Toxocara canis and Toxocara cati). These parasites harch in the men´s intestines and the larvas are distributed around the organism, mainly in the following organs: liver, lungs, hearth and brain. In their migration, the larvas leave traces of hemorrhage, necrosis and inflammatory cells; several of them are destroyed by the host´s immune answer and others form eosinophilic granulomas. The symptoms depend on the affected tissue or organ, on the infection intensity and on the level of induced immunologic answer. The case of a male patient, aged 72 years-old is presented. He entered the Medicine Service of the Teaching Military Hospital “Dr. Mario Muñoz Monroy”, of Matanzas with fever, diarrhea, dry cought, asthenia, anorexia and weight loss.Visceral larva migrans was diagnosed. The presentation of the case was decided because of the atypical patient´s age and the complexity of the diagnosis (AU).

Hepatic Toxocariasis with Atypical CT and MR Imaging Findings: a Case Report

Hepatic toxocariasis is a type of visceral larva migrans caused by the migration of second-stage larvae of certain nematodes such as Toxocara canis to the liver. Histologically, the condition is characterized by granulomatous lesions containing eosinophils and inflammatory cells. We report a case of hepatic toxocariasis with atypical clinical and radiologic findings presenting as distinct, solitary hepatic nodule detected in a middle-aged woman.

Toxocara canis Mimicking a Metastatic Omental Mass from Sigmoid Colon Cancer: A Case Report

Toxocara canis is an important roundworm of canids and a fearsome animal parasite of humans. Human infections can lead to syndromes called visceral larva migrans (VLM), ocular larva migrans, neurotoxocariasis, and covert toxocariasis. VLM is most commonly diagnosed in children younger than 8 years of age, but adult cases are relatively frequent among those infected by ingesting the raw tissue of paratenic hosts in East Asia. This research reports the case of a 59-year-old man with sigmoid colon cancer, who visited our institution for surgery. An intraperitoneal mass was found on preoperative computed tomography, and it was thought to be a metastatic mass from sigmoid colon cancer. A postoperative histologic examination and serum test showed eosinophilic granuloma due to toxocariasis. Diagnosis of VLM is often difficult and highly suspicious in adults. Researchers suggest, although rarely, that VLM be included in the differential diagnosis as a cause of intraperitoneal tumors.

Toxocaríase experimental em hamster / Experimental toxocariasis in hamsters

INTRODUÇÃO: Toxocaríase é uma infecção parasitária de distribuição global, causada pela fase larval de Toxocara spp. Os hospedeiros naturais são cães e gatos, nos quais o parasita completa o ciclo chegando a fase adulta. Outros hospedeiros podem ser infectados pela fase larval do parasita, após ingestão de ovos embrionados do solo, mãos contaminadas, fomites, ou ingestão de carne ou vísceras de animais infectados. Em hospedeiros paratênicos o parasita não completa o ciclo, invadindo em estágio larval vísceras ou outros tecidos, onde podem sobreviver e induzir a patologia. O presente estudo teve como objetivo caracterizar o hamster (Mesocricetus auratus), como modelo experimental de toxocaríase, inicialmente através do estudo das lesões histopatológicas em fígado, pulmão e rim. A caracterização da resposta imunológica do modelo, foi feita através do estudo de citocinas envolvidas nas respostas Th1 e Th2, e foi sugerida uma correlação entre alterações glomerulares e depósitos de complexos antígenos-anticorpo pré-formados na circulação. MÉTODOS: Hamsters foram inoculados com ovos embrionados de Toxocara canis, e mantidos no biotério do Instituto de Medicina Tropical de São Paulo. O estudo histopatológico foi desenvolvido utilizando-se cortes parafinados corados por hematoxilina e eosina. Para detecção de antígenos nos tecidos foram realizadas reações imunohistoquímicas, utilizando-se anticorpo monoclonal e policlonal anti- Toxocara canis. Utilizando-se o soro dos animais infectados e animais controle, foi realizada pesquisa de antígeno e anticorpo por ELISA. Para pesquisa de imunoglobulinas IgG e IgM e complemento, foram utilizados cortes congelados de rins para realização de reação de Imunofluorescência. Fragmentos de rins foram incluídos para utilização em microscopia eletrônica, para detecção de antígenos de toxocara e de imune complexos. Para caracterização de resposta imunológica foram estudadas citocinas envolvidas na resposta Th1 e Th2 por técnica de...

INTRODUCTION: Toxocariasis is a parasitic infection of global distribution, caused by the larval stage of Toxocara spp. The natural hosts are dogs and cats, in which the parasite completes the cycle reaching adulthood. Other hosts can be infected with the larval stage of the parasite, after ingestion of embryonated eggs from the soil, contaminated hands, fomites, or ingestion of meat or viscera of infected animals. In paratenics hosts the parasite not complete the cycle, encroaching on larval stage in viscera or other tissues where they can survive and induce pathology. The present study aimed to characterize the hamster, Mesocricetus auratus, as experimental model of toxocariasis, initially through the study of histopathological lesions in the liver, lung and kidney. The characterization of immune response model, was made through the study of cytokines Th1 and Th2 responses involved, and a correlation was suggested between glomerular changes and antibody-antigen complexes deposits preformed in the circulation. METHODS: Hamsters were inoculated with embryonated eggs of Toxocara canis, and kept in the bioterium of the Institute of Tropical Medicine of the São Paulo. The histopathologic study was developed using paraffin slides stained by hematoxylin and eosin. For detection of antigens in tissues immunohistochemistry reactions were performed using monoclonal and polyclonal anti-Toxocara canis sera. Using the serum of infected and control animals, search has been carried out of antigen and antibody by ELISA. For the search of immunoglobulins IgG, IgM and complement, were used slides prepared from frozen fragments of kidneys and a immunofluorescence reaction. Fragments of kidneys were included for electron microscopy to detect antigens of Toxocara and immune complexes. For characterization of Th1 and Th2 response cytokines involved were detected by RT-PCR technique. RESULTS: Histopathological findings demonstrated since the beginning of the...

Determination of IgG avidity in BALB/c mice experimentally infected with Toxocara canis / Determinação da avidez de IgG em camundongos BALB/c experimentalmente infectados com Toxocara canis

Toxocariasis is a zoonotic disease in that IgM titers can remain high for long periods making difficult to determine the stage of the disease. The aim of this study is to investigate the applicability of indirect ELISA, associated with urea, to discriminate between the acute and chronic toxocariasis. IgG avidity was evaluated in 25 BALB/c mice experimentally infected with 1000 Toxocara canis eggs. Blood samples were collected, and sera treated with 6 M urea and assayed by ELISA every two weeks. The percent IgG avidity was determined using the mean absorbance of sera treated with urea, divided by the mean absorbance of untreated sera. In the first 15 days post-inoculation, was observed a low percentage, between 7.25 and 27.5%, IgG avidity, characteristic of an acute infection. After 60 days of infection, all the mice showed between 31.4 and 58% IgG avidity, indicating a chronic infection.

A toxocaríase é uma zoonose na qual os títulos de IgM podem permanecer elevados por longos períodos, tornando difícil a determinação do estágio em que a doença se encontra. O objetivo deste estudo foi investigar a aplicabilidade de um teste indireto de ELISA, associado com ureia, para fazer a discriminação entre as fases aguda e crônica da toxocaríase. A avidez de IgG foi avaliada em 25 camundongos BALB/c experimentalmente infectados com 1000 ovos embrionados de Toxocara canis. A cada duas semanas, amostras de sangue foram coletadas, o soro tratado com ureia 6M e realizado o ensaio pela técnica de ELISA. O percentual de avidez de IgG foi determinado, usando-se a média das absorbâncias dos soros tratados com ureia dividida pela média das absorbâncias dos soros não tratados. Nos primeiros 15 dias pós-inoculação, foi observado um baixo percentual de avidez de IgG, entre 7,25 e 27,5%, característico da fase aguda da infecção. Após 60 dias de infecção, todos apresentaram avidez de IgG entre 31,4 e 58%, indicando a fase crônica da infecção.

Bladder and Liver Involvement of Visceral Larva Migrans May Mimic Malignancy / Journal of the Korean Cancer Association, 대한암학회지

Visceral larva migrans (VLM) syndrome is a clinical manifestation of systemic organ involvement by Toxocara species. VLM with involvement of the bladder and liver is a rare finding. A 62-year-old woman presented with diffuse bladder wall thickening and multiple liver masses with peripheral eosinophilia and urinary symptoms. We considered malignancy or eosinophilic cystitis through clinical manifestations and imaging findings. However, no suspicious malignant lesions were observed on cystoscopy and liver mass biopsy revealed the presence of eosinophilic necrotizing granuloma without malignant cells. Anti-Toxocara antibodies were detected by western blotting and the patient was diagnosed with VLM syndrome. After taking prednisolone, urinary symptoms disappeared. On abdominal CT scan taken after three months, the size of multiple liver masses and bladder wall thickening had decreased. VLM syndrome should be suspected in patients with an atypical imaging pattern and peripheral eosinophilia.

Vertical transmission of Toxocara canis in successive generations of mice / Transmissão vertical de Toxocara canis em gerações sucessivas de camundongos

Visceral toxocariasis is a neglected zoonosis caused by Toxocara canis larvae in unusual hosts. In dogs, the definitive host, the infection occurs mainly through transplacental and transcolostral transmission. Studies on experimental models have shown that vertical transmission may result from acute infections. Considering that toxocariasis is characterized as a chronic infection, with possible reactivation of larvae present in the brain, this study evaluated the presence of larvae in the brain of female BALB/c mice and their offspring with chronic infection during three successive pregnancies. ELISA-TES was used to evaluate the antibody levels. T. canis larvae were detected in the brain tissue of the mice during the three successive generations evaluated. The offspring's IgG level gradually decreased, and mean absorbance (ABS) above the cutoff point (0.070) was observed only at 30 (0.229) and 50 (0.096) days of age, while IgM was not detected. The infections in the offspring confirmed that vertical transmission of T. canis larvae occurred during chronic toxocariasis in three successive generations of mice.

A toxocaríase visceral é uma zoonose negligenciada causada por larvas de Toxocara canis em hospedeiros não usuais. Em cães, os hospedeiros definitivos, a infecção ocorre normalmente por transmissão transplacentária e através do colostro. Estudos com modelos experimentais têm demonstrado a ocorrência de transmissão vertical durante a infecção aguda. Considerando que a toxocaríase é caracterizada como uma infecção crônica, com uma possível reativação das larvas presentes no cérebro, este estudo avaliou a presença de larvas no cérebro de camundongos Balb/C fêmeas e suas proles com infecção crônica durante três gestações sucessivas. Para avaliar os níveis de anticorpos foi utilizado ELISA-TES. Larvas de T. canis foram detectadas no encéfalo dos animais durante as três gerações sucessivas avaliadas. O nível de IgG das proles foi diminuindo gradualmente e as médias de absorbâncias (ABS) acima do ponto de corte (0,070) foram evidenciadas somente aos 30 (0,229) e 50 dias (0,096) de vida, enquanto que não foi detectada IgM. Infecções das proles confirmam a transmissão vertical de larvas de T. canis durante a toxocaríase crônica em três gerações sucessivas de camundongos.

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.

An interesting case of visceral larva migrans (VLM).

Human toxocariasis is primarily a soil transmitted zoonosis.We report a case of two and half year old male child who presented with fever, anorexia and hepatosplenomegaly. Hemogram showed anaemia (Hb 5.8), leukocytosis (TLC 26,500) and marked eosinophilia (AEC 14,100). Further investigations revealed hypergammaglobulinemia, CT scan of Abdomen showed low density lesions in liver and liver biopsy showed noncaeseating epitheloid cell granulomas and infiltrates of lymphocytes and eosinophils. We decided to get a confirmatory serological diagnostic test for Toxocara and the result was positive .Child was treated for it with Oral Albendazole and responded dramatically.

Eosinophilic Myocarditis Associated with Visceral Larva Migrans Caused by Toxocara Canis Infection

A 41-year-old woman who was diagnosed with myocarditis presented eosinophilia. Since the antibody against Toxocara canis (T. canis) was positive, we diagnosed that she had visceral larva migrans due to T. canis associated with myocarditis. She was treated with oral albendazole and prednisolone for two weeks, eosinophil count and hepatic enzymes were normalized after completion of treatment. This is the first report of myocarditis caused by T. canis infection in Korea.

Transmission of Toxocara canis via Ingestion of Raw Cow Liver: A Cross-Sectional Study in Healthy Adults

The aim of this study is to ascertain the relationship between ingestion of raw cow liver and Toxocara canis infection. A total of 150 apparently healthy adults were divided into 2 groups; 1 group consisted of 86 adults with positive results of Toxocara ELISA, and the other group of 64 adults with negative results. One researcher collected the history of ingestion of raw cow liver within 1 year and recent history of keeping dogs. Among 86 seropositive adults for T. canis, 68 (79.1%) had a recent history of ingestion of raw cow liver. Multivariate statistical analysis showed that a recent ingestion of raw cow liver and keeping dogs were related to an increased risk of toxocariasis (odds ratios, 4.4 and 3.7; and 95% confidence intervals, 1.9-10.2 and 1.2-11.6, respectively). A recent history of ingestion of raw cow liver and keeping dogs was significantly associated with toxocariasis.

Meningitis by Toxocara canis after Ingestion of Raw Ostrich Liver

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.

Seroprevalencia contra toxocara canis en niños de 1 a 6 años con y sin síntomas respiratorios de barquisimeto, venezuela / Seroprevalence against Toxocara canis in children of 1-6 years without respiratory symptoms barquisimeto, Venezuela

Sabiendo la existencia de casos de Síndrome de Larva Migrans Visceral en Venezuela, es necesario conocer la seroprevalencia contra uno de sus agentes causales: Toxocara canis. Determinar la presencia de anticuerpos séricos IgG anti- Toxocara canis y su relación con síntomas respiratorios y factores de riesgo para Síndrome de Larva Migrans Visceral en niños de 1 a 6 años, que acudieron a dos ambulatorios urbanos de Barquisimeto-Venezuela. Se evaluaron 215 niños y niñas de 1 a 6 años de edad con y sin síntomas respiratorios. Previa información y solicitud del consentimiento informado de sus representantes, se les entrevistó y tomó muestra de sangre para determinar anticuerpos IgG séricos anti-Toxocara canis por ELISA, con el estuche DRG®. Se calcularon porcentajes y proporciones y se usaron Prevalencia Relativa (PR) y Chi Cuadrado con intervalo de confianza de 95%. Se detectaron anticuerpos en 34,4%. El mayor porcentaje de seroreactivos estuvo representado por los niños con síntomas respiratorios (83,8%), los del grupo de edad de 3 a 4 años (55,4%), el sexo masculino (54,1%), quienes refirieroncontacto con tierra y/o geofagia (95,9%) y contacto con cachorros caninos menores de 3 meses de edad (90,5%), quienes consumían agua de calidad inadecuada (85,1%) y quienes disponían inadecuadamente las excretas caninas (60,8%). La elevada seroprevalencia crea la necesidad de nuevos estudios para evaluar con precisión las características epidemiológicas de la infección por T. canis en Lara y Venezuela a fin de establecer planes adecuados de control

In view of the presence of Visceral Larva Migrans Syndrome in Venezuela, it is necessary to know the seroprevalence against one of its causal agents: Toxocara canis. A transversal study was performed to determine the presence of serum IgG anti-Toxocara canis antibodies and their relation with respiratory symptoms and risk factors for Visceral Larva Migrans Syndrome in patients from 1 to 6 years, who assisted to two urban outpatient clinics of Barquisimeto-Venezuela. 215 children 1 to 6 years old with and without respiratory symptoms were evaluated. Previous information on the investigation and request of the consent in writing of their care givers, an interview was withheld and a blood sample was drawn to determine serum IgG anti-Toxocara canis antibodies by the ELISA method, with DRG® commercial kit. Percentage and proportions were calculated and Relative Prevalence (RP) and x Squared used, with an interval of statistical confidence of 95%. Antibodies were detected in 34.4% of the children. The greater percentage of seroreactives was represented by children with respiratory symptoms (83.8%), those inthe age group of 3 to 4 years (55.4%), boys (54.1%), those who referred soil contact and/or geophagy (95.9%) and contact with puppies under three months of age (90.5%), that consumed water of inadequate quality (85.1%) and that had inadequate disposal of canine excretes (60.8%). The high seroprevalence creates the necessity of new studies to evaluate accurately the epidemiologic characteristics of the infection by T. canis in Lara and Venezuela in order to establish suitable control plans

Anti-Toxocara antibodies detected in children attending elementary school in Vitoria, State of Espírito Santo, Brazil: prevalence and associated factors / Anticorpos anti-Toxocara em crianças admitidas na escola fundamental em Vitória, Estado do Espírito Santo: prevalência e fatores associados

INTRODUCTION: The aim of this study was to evaluate the frequency of anti-Toxocara antibodies in serum from 7-year-old children attending elementary school in Vitória-ES, Brazil and to correlate these antibodies with socio-demographic factors, the presence of intestinal helminths, blood eosinophil numbers, past history of allergy or asthma, and clinical manifestations of helminth infections. METHODS: The detection of anti-Toxocara antibodies was performed using an ELISA (Cellabs Pty Ltd)on serum from 391 children who had already been examined by fecal examination and blood cell counts. Data from clinical and physical examinations were obtained for all children. RESULTS: The prevalence of anti-Toxocara antibodies was 51.6%, with no gender differences. No significant differences were observed between positive serology and the presence or absence of intestinal worms (60.3 and 51.7%, respectively; p = 0.286). The only variables significantly related to positive serology were onycophagy and the use of unfiltered water. Although eosinophilia (blood eosinophil count higher than 600/mm³) was significantly related to the presence of a positive ELISA result, this significance disappeared when we considered only children without worms or without a past history of allergy or asthma. No clinical symptoms related to Toxocara infection were observed. CONCLUSIONS: There is a high prevalence of anti-Toxocara antibodies in children attending elementary schools in Vitória, which may be partially related to cross-reactivity with intestinal helminths or to a high frequency of infection with a small number of Toxocara eggs.

INTRODUÇÃO: O objetivo desse estudo foi avaliar a prevalência de anticorpos anti-Toxocara em crianças admitidas no primeiro ano de escola fundamental em Vitória e correlacionar com variáveis sociodemográficas, helmintos intestinais, eosinófilos no sangue, geofagia, onicofagia, história de asma e alergia cutânea e manifestações clínicas. MÉTODOS: A pesquisa de anticorpos anti-Toxocara, utilizando um teste de ELISA (Cellabs), foi realizada em 391 crianças nas quais foram realizados exames parasitológicos de fezes e hemograma completo. Todas as crianças foram submetidas a exame clínico e físico. RESULTADOS: A prevalência de reação positiva foi de 51,6%, sem diferença entre os sexos. Não foram observadas diferenças significativas na prevalência de reação positiva em crianças com ou sem helmintos intestinais (60,3 e 51,7%, respectivamente; p = 0.286). Ainda que a frequência de eosinófilos acima de 600/mm³ tenha sido significativamente maior em crianças com sorologia positiva, a significância desapareceu quando se considerou as crianças sem helmintos intestinais ou história pregressa de asma ou alergia cutânea. As únicas variáveis significativamente correlacionadas, de modo independente, com a presença de sorologia positiva foram onicofagia e hábito de beber água não filtrada. Nenhuma criança apresentou manifestação clínica relacionada com a presença de anticorpos anti-Toxocara. CONCLUSÕES: A prevalência de anticorpos anti-Toxocara em crianças admitidas nas escolas elementares em Vitória é alta, a qual pode estar, em parte, relacionada à reação cruzada com antígenos de helmintos intestinais ou devida a frequente exposição a baixas quantidades de ovos do Toxocara.

Prueba de avidez de los anticuerpos IgG en la infección por Toxocara canis / IgG antibodies avidity test in Toxocara canis infection / O teste de avidez dos anticorpos IgG na infecção por Toxocara canis

A fin de evaluar la utilidad de la prueba de avidez de los anticuerpos IgG para el reconocimiento de la fase de infección de la toxocariosis en individuos con alto nivel de exposición al parásito, se estudiaron 142 niños asintomáticos de ambos sexos, de 1-6 años de edad, residentes en la ciudad de Resistencia (NE de Argentina), con eosinofilia > 10% y con exámenes coproparasitológicos negativos para helmintos. Se realizó la prueba de ELISA-IgG en todos los casos y en aquellos con títulos > 1/80 se determinó el índice de avidez de IgG. De los 142 niños estudiados, 82 (57,7%) resultaron positivos a la prueba de ELISA-IgG pero sólo 6 (7.3%) tuvieron Índice de avidez menor al 50%, cinco tenían entre 1 y 2 años de edad y el restante 5 años (mediana: 1,5 años). Cuatro tuvieron títulos moderados de IgG (entre 1/80 y 1/640) y 2 títulos altos (entre 1/1280 y 1/10240). Los otros 76 niños con índice de avidez mayor al 50% tenían entre 18 meses y 5,5 años de edad (mediana: 4 años), 44 tuvieron títulos serológicos moderados y 32, títulos altos. Los resultados hallados en este trabajo reafirman que la población de la ciudad de Resistencia presenta altos niveles de exposición a T. canis y que la determinación del índice de avidez de IgG resulta útil para el diagnóstico diferencial entre toxocariosis reciente o tardía, aunque es más efectiva para descartar una infección reciente que para confirmarla.

In order to evaluate the usefulness of the IgG avidity test to recognize the phase of T. canis human infection in individuals highly exposed to the parasite, 142 asymptomatic children of both sexes, 1-6 years old, living in Resistencia (Northeastern Argentina), with eosinophilia > 10% and without helminthic intestinal infestation were studied. ELISA-IgG test was performed in all cases, and in those with serological titers > 1/80 IgG avidity was also measured. Out of 142 children studied, 82 (57.7%) were positive to ELISA test, but only 6 (7.3%) had an IgG avidity index < 50%. Five of them were aged between 1 to 2 years and the other was 5 years old (median 1.5 years). Four had moderate serological titers (between 1/80 and 1/640) and two had high titers (between 1/1280 and 1/10240). The other 76 children with IgG avidity indexes > 50% were between 18 months and 5.5 years old (median 4 years), 44 had moderate serological titers and 32 had high titers. The results found in this study reaffirm that the population in Resistencia city is highly exposed to T. canis infection and that the IgG avidity test may be helpful in differential diagnosis of recent and past toxocariosis, though it would be more effective to rule out a recently acquired infection than to confirm it.

Com o fim de avaliar a utilidade da prova de avidez dos Acs IgG para o reconhecimento da fase de infecção de toxocaríase em indivíduos com alto nível de exposição ao parasita, foram estudadas 142 crianças assintomáticas de ambos os sexos de 1 a 6 anos de idade, residentes na cidade de Resistencia (noreste argentino) com eosinofilia > 10% e com exames coproparasitológicos negativos para helmintos. Foi realizada a prova Elisa-IgG em todos os casos e naqueles com títulos > 1/80 foi determinado o índice de avidez de IgG. Das 142 crianças estudadas, 82 (57,7%) resultaram positivas à prova de Elisa-IgG porém só 6 (7,3%) tiveram índice de avidez < a 50%, 5 tinham entre 1 e 2 anos de idade e as outras 5 anos (média: 1,5 anos). Quatro tiveram títulos moderados de IgG (entre 1/80 e 1/640) e 2 títulos altos (entre 1/1280 e 1/10240). As outras 76 crianças com índice de avidez maior a 50% tinham entre 18 meses e 5,5 anos de idade (média: 4 anos), 44 tiveram títulos sorológicos moderados e 32 títulos altos. Os resultados encontrados neste trabalho reafirmam que a população da cidade de Resistencia apresenta altos níveis de exposição à T. canis e que a determinação do índice de avidez de IgG resulta útil para o diagnostico diferencial entre toxocaríase recente ou tardia, embora seja mais efetiva para descartar uma infecção recente que para confirmá-la.

Presence of eggs of Toxocara spp. and hookworms in a student environment in Rio Grande do Sul, Brazil / Presença de ovos de Toxocara spp. e ancilostomatídeos em ambiente estudantil do Rio Grande do Sul, Brasil

Environmental contamination by parasite forms was studied on a university campus in the municipality of Pelotas, Rio Grande do Sul. Soil samples were analyzed using the modified Caldwell & Caldwell technique to identify parasite forms. Nematode eggs were detected in 62 percent of the samples. Among the parasites detected, eggs of Toxocara spp. and Ancylostomatidae were the most prevalent parasites in the studied area throughout the study period. The results demonstrated that there is significant environmental contamination, thereby representing a risk of zoonotic infection for humans frequenting the study area.

A contaminação ambiental por formas parasitárias foi estudada na área do campus universitário no município de Pelotas, Rio Grande do Sul. Amostras de solo foram analisadas para identificação de formas parasitárias e a presença de ovos de nematóides foi verificada em 62 por cento das amostras. Entre os parasitos observados destacam-se a presença de ovos de Toxocara spp. e de ancilostomatídeos em todo período estudado. Os resultados demonstram que há contaminação ambiental significativa, o que representa risco de infecção zoonótica aos humanos que frequentam a região estudada.

Identification of candidate antigens from adult stages of Toxocara canis for the serodiagnosis of human toxocariasis

In the present work, we identified adult Toxocara canis antigens through sodium dodecyl sulfate-polyacrylamide gel electrophoresis for potential use in human toxocariasis immunodiagnosis. The sensitivity and specificity of several semi-purified antigens, as well as their cross-reactivity with other parasitic infections, were assessed by IgM and IgG-enzime linked immunosorbent assay. Whilst we found that the crude extract of the parasite presented limited sensitivity, specificity and high cross-reactivity against other parasites, we identified 42, 58, 68 and 97-kDa semi-purified antigens as the most promising candidates for immunodiagnosis. Moreover, the 58 and 68-kDa antigens presented the lowest IgM cross-reactivity. When tested as a combination, a mixture of the 58 and 68-kDa antigens presented 100 percent sensitivity and specificity, as well as minor cross-reactivity. Although the combination of the 42, 58, 68 and 97-kDa antigens presented 100 percent sensitivity at a dilution of 1:40, the low specificity and high cross-reactivity observed suggested a limited use for diagnostic purposes. Our data suggested that the 58 and 68-kDa antigens might be most suitable for the immunodiagnosis of human toxocariasis.