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.

Síndrome de larva migrans visceral y absceso hepático: Reporte de un caso / Visceral larva migrans syndrome and hepatic abscess: A case report

La infección por T oxocara canis o catis es una zoonosis diseminada en el ser humano. La toxocariasis puede coexistir con otras parasitosis endémicas. El hombre actúa como huésped no natural y adquiere la infección a través de la ingesta de huevos del geohelminto. Estos pueden localizarse en la tierra, los patios y los juegos de los niños, y son eliminados, principalmente, por perros o gatos. Existen distintos espectros en la presentación clínica; algunos de ellos son toxocariasis ocular, larva migrans visceral, toxocariasis encubierta y neurotoxocariasis. Se presenta el caso de un paciente de 2 años y 3 meses de edad, con antecedente de síntomas respiratorios, fiebre prolongada y hepatomegalia, con resultados de laboratorio que informa hipereosinofilia, hipergammaglobulinemia y serología positiva para toxocariasis (ensayo por inmunoabsorción ligado a enzimas). Se plantea el diagnóstico de síndrome de larva migrans visceral.

Toxocariasis canis or catis is a zoonotic infection disseminated in humans. Human beings can act as non-natural hosts in which the parasite can survive for long periods of time and they become infected by the ingestion of geohelminth eggs. These can be located on the ground, playgrounds and children's games, and are mostly eliminated by dogs or cats. There are different spectra in the clinical presentation of this infection, which can vary from an asymptomatic host to the production of serious organic lesions; some of them are ocular toxocariasis, visceral larva migrans, covert toxocariasis and neurotoxocariasis. In this case report a patient who presents with a history of respiratory problems, prolonged fever, and hepatomegaly. Laboratory analyses show hypereosinophilia, hypergammaglobulinemia and serodiagnosis is positive for toxocariasis. Preliminary diagnosis: Visceral Larva Migrans Syndrome.

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.

Eosinophilic Myocarditis-Associated Toxocariasis / 대한내과학회지

Human toxocariasis is a common helminthozoonosis due to the infestation of toxocara canis or toxocara cati larvae, and is a common cause of blood eosinophilia in Korea. Toxocariasis has various clinical manifestations depending on the involved organ, and cardiac involvement can range from asymptomatic to fulminant myocarditis with cardiogenic shock. Treatment of toxocariasis is based on corticosteroid and anthelmintic therapies. Here, we report a case of a 57-year-old male with eosinophilic myocarditis caused by toxocariasis as diagnosed via serial echocardiography follow up.

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.

Toxocarosis y colecistitis aguda alitiásica: ¿consecuencia o coincidencia? / Toxocarosis and acalculous acute cholecystitis: consequence or coincidence?

La toxocarosis humana es una parasitosis larvaria crónica catalogada dentro de las cinco enfermedades subestimadas más importantes por los CDC. Las larvas pueden diseminarse por vía sistémica y migrar a distintos tejidos (larva migrans visceral) incluyendo el hígado y vesícula biliar. La colecistitis aguda acalculosa (CAA) es una enfermedad rara en niños. El diagnóstico se basa en parámetros clínicos y criterios imagenológicos. Se ha asociado a sepsis, shock, trauma, quemaduras, enfermedades sistémicas graves, anomalías congénitas e infecciones, como también en niños sanos. Presentamos el caso de una toxocarosis infantil con síntomas clínicos y criterios imagenológicos compatibles con una CAA tratado médicamente, y discutir la relación entre ambos cuadros en base a la evidencia publicada.

Human toxocarosis is a chronic larval parasitosis listed as one of the five most important neglected diseases by the CDC. The larvae can spread systemically and migrate to different tissues including liver and gallbladder. Acalculous acute cholecystitis (AAC) is a rare disease in children. The diagnosis is based on clinical parameters and imaging criteria. It has been reported in relation to sepsis, shock, trauma, burns, severe systemic diseases, congenital anomalies, infections and also in healthy children. We report a pediatric case of toxocarosis, with clinical symptoms and imaging criteria compatible with AAC treated medically, and discuss the relationship between toxocarosis and AAC based on published evidence.

Draft Genome of Toxocara canis, a Pathogen Responsible for Visceral Larva Migrans

This study aimed at constructing a draft genome of the adult female worm Toxocara canis using next-generation sequencing (NGS) and de novo assembly, as well as to find new genes after annotation using functional genomics tools. Using an NGS machine, we produced DNA read data of T. canis. The de novo assembly of the read data was performed using SOAPdenovo. RNA read data were assembled using Trinity. Structural annotation, homology search, functional annotation, classification of protein domains, and KEGG pathway analysis were carried out. Besides them, recently developed tools such as MAKER, PASA, Evidence Modeler, and Blast2GO were used. The scaffold DNA was obtained, the N50 was 108,950 bp, and the overall length was 341,776,187 bp. The N50 of the transcriptome was 940 bp, and its length was 53,046,952 bp. The GC content of the entire genome was 39.3%. The total number of genes was 20,178, and the total number of protein sequences was 22,358. Of the 22,358 protein sequences, 4,992 were newly observed in T. canis. Following proteins previously unknown were found: E3 ubiquitin-protein ligase cbl-b and antigen T-cell receptor, zeta chain for T-cell and B-cell regulation; endoprotease bli-4 for cuticle metabolism; mucin 12Ea and polymorphic mucin variant C6/1/40r2.1 for mucin production; tropomodulin-family protein and ryanodine receptor calcium release channels for muscle movement. We were able to find new hypothetical polypeptides sequences unique to T. canis, and the findings of this study are capable of serving as a basis for extending our biological understanding of T. canis.

Enhanced Resolution of Eosinophilic Liver Abscess Associated with Toxocariasis by Albendazole Treatment / 대한소화기학회지

BACKGROUND/AIMS: Visceral larva migrans, caused by Toxocara canis and Toxocara cati, has emerged as a significant cause of eosinophilic liver abscess (ELA). Differentiation of ELA associated with toxocariasis (ELA-T) from metastasis or primary liver malignancy is sometimes difficult. However, the role of albendazole treatment remains uncertain in this condition. The aim of this study was to evaluate whether albendazole can enhance the radiologic resolution of ELA-T. METHODS: We retrospectively reviewed the medical records of the patients diagnosed with ELA-T at our institution between January 2008 and December 2011. ELA-T was diagnosed based on the imaging findings on computed tomography or magnetic resonance imaging and the presence of positive serum IgG antibody for Toxocara canis. Among a total of 163 patients, 32 patients received albendazole (albendazole group) and 131 did not (control group). Baseline characteristics and fate of liver nodules were compared between the two groups. RESULTS: Baseline characteristics (age, sex, number and maximal size of lesions, eosinophil count) were similar between the two groups. Median duration for achieving radiologic resolution in the albendazole group was significantly shorter than in the control group (207 days [range 186-228] vs. 302 days [range 224-380], p=0.023). In Cox regression analysis of the cumulative rates of radiologic resolution, the hazard ratio for albendazole treatment was 1.99 (95% confidence interval, 1.22-3.23). CONCLUSIONS: Radiologic resolution of ELA-T can be accelerated with albendazole treatment. Hence, inconvenience associated with long-term follow-up and unnecessary worries among patients can be eliminated with albendazole treatment.

Toxocariasis: A Rare Cause of Multiple Cerebral Infarction

Toxocariasis is a parasitic infection caused by the roundworms Toxocara canis or Toxocara cati, mostly due to accidental ingestion of embryonated eggs. Clinical manifestations vary and are classified as visceral larva migrans or ocular larva migrans according to the organs affected. Central nervous system involvement is an unusual complication. Here, we report a case of multiple cerebral infarction and concurrent multi-organ involvement due to T. canis infestation of a previous healthy 39-year-old male who was admitted for right leg weakness. After treatment with albendazole, the patient's clinical and laboratory results improved markedly.

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...

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.

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.

Frequência de estruturas parasitárias em praças e parques públicos da cidade de Porto Alegre-RS / Frequency parasitic structures in public squares and parks of the city of Porto Alegre-RS

O solo é um dos principais reservatórios de estruturas parasitárias e importante vetor na disseminação de parasitos entre a população, pois nele alguns helmintos e protozoários desenvolvem uma etapa do seu ciclo biológico. No período de julho de 2001 a junho de 2004, foram coletadas 3.120 amostras de solo em 18 áreas públicas de Porto Alegre-RS. Das amostras processadas pelo método de centrífugo-flutuação, 40,8 por cento revelaram a presença de estruturas parasitárias e 100 por cento das praças públicas estavam contaminadas. As estruturas encontradas foram: ovos de Ascaris spp. (10,2 por cento), ovos de Trichuris spp. (4,4 por cento), ovos de Toxocara spp. (4,2 por cento), ovos da superfamília Strongyloidea(3,4 por cento), oocistos de protozoários (16,0 por cento) e larvas de helmintos (18,0 por cento). Esses dados evidenciam a necessidade de implementação de medidas de controle que reduzam o risco de contaminação desses lugares públicos...

Soil is a major reservoir of parasite structures and is an important vehicle for the spread of parasites in the population because some helminths and protozoa spend a stage of their life cycle there. From July 2001 to June 2004 3,120 soil samples were collected in 18 areas of Porto Alegre, RS. The samples were processed by the flotation method and 40.8 percent had parasite structures, while 100 percent of the public squares were contaminated. The structures were: Ascaris spp. (10.2 percent ), eggs of Trichuris spp. (4.4 percent ), Toxocara spp. (4.2 percent ), eggs of the Strongyloidea superfamily (3.4 percent ), protozoan oocysts (16.0 percent ) and larvae of helminths (18.0 percent ). Based on these data, there is a need to implement control measures that reduce the risk of contamination of public places...

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.

Foodborne Eosinophilia due to Visceral Larva Migrans: A Disease Abandoned

No abstract available.

A Case of Toxocariasis with Visceral Larva Migrans Combined with Ocular Larva Migrans / 대한내과학회지

Toxocariasis is an infection in a human host caused by Toxocara canis or Toxocara cati larvae. Clinical manifestations are classified according to the organs affected, such as visceral larva migrans (VLM) and ocular larva migrans (OLM). Epidemiological evidence suggests that OLM tends to occur in the absence of systemic involvement and vice versa, which has led to two manifestations of this infection being reclassified as VLM and OLM. No case of a patient with VLM combined with OLM has been reported in Korea. Here, we report a case of VLM combined with OLM in a 51-year-old female caused by massive ingestion of raw cow meat, manyplies, and liver.

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