SUMMARYIn the present paper the main aspects of the natural history of human infection by Toxocara larvae that occasionally result in the occurrence of visceral and/or ocular larva migrans syndrome were reviewed. The contribution by Brazilian researchers was emphasized, especially the staff of the Tropical Medicine Institute of São Paulo (IMT).

SUMMARYTo estimate the frequency of anti-Toxocara sp. antibodies, and evaluate factors associated with this infection, sera from 242 male and female children, aged from one to fifteen years old, attended at the Hospital of the Federal University of Uberlândia, Minas Gerais State, Brazil, were analyzed by ELISA. Information on the patients was collected and registered using an investigative questionnaire, and details on possible clinical alterations were obtained from the medical charts of 187 patients. Of a total of 242 samples, 21 (8.7%) were positive for anti-Toxocara sp. antibodies. The presence of dogs and cats and the school variable (place of contact), appeared to be significantly associated (p < 0.05) with a positive serology. Respiratory symptoms and eosinophil counts greater than 20% also showed a positive statistical correlation with a positive serology for Toxocara sp.. Factors such as sex and age, and symptoms like headache, stomach ache, convulsive crises and anemia were not associated with toxocariasis.

The aim of this note was to record for the first time the recovery of Toxocara canis larvae from tissues and organs of Rattus norvegicus (Berkenhout, 1769), Wistar strain, until the 60th day after experimental infection. Rats were orally infected with embryonated T. canis eggs, killed on days 3, 5, 8, 10, 15, 30, and 60

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In a transversal study on a sample of 386 children and adolescents from an outpatient clinic for filariasis in Recife, Northeast Brazil, the frequency of anti-Toxocara antibodies and its relation to age, gender, number of peripheral eosinophils, Wuchereria bancrofti microfilariae and intestinal helminths was determined. The total anti-Toxocara IgG antibody frequency was 39.4%, by ELISA technique. The difference in frequency between males (40.1%) and females (37.6%) was not statistically significant. The 6 to 10-year-old subset presented the highest frequency of anti-Toxocara antibodies (60%), and within this age group there was a statistically significant male bias. There was also a significant association between the number of eosinophils and the presence of anti-Toxocara antibodies. Intestinal parasite frequency was 52.1%, but no association was found between this data and the presence of anti-Toxocara antibodies. In the present sample, 42.2% of the patients were Wuchereria bancrofti carriers, however, again this was not associated with the presence of anti-Toxocara antibodies. In conclusion, anti-Toxocara antibodies were highly prevalent in this sample. The present data show that there is no cross correlation between anti-Toxocara IgG antibody and the presence of intestinal helminths and filariasis.

Revista da Sociedade Brasileira de Medicina Tropical 41(6):648-653, nov-dez, 2008 ARTIGO/ARTICLEApesar da prevalência dos distúrbios gastrointestinais causados pelo Strongyloides stercoralis ser rara, em áreas urbanas e bem desenvolvidas, esses são importantes no Brasil, onde a ocorrência dessa parasitose é favorecida pelo clima tropical do país e pelas baixas condições sociais e sanitárias presentes, ainda hoje, em várias regiões. A estrongiloidíase disseminada, rara entre a população de imunocompetentes, é muito importante em indivíduos imunodeprimidos; ela é decorrente da capacidade de auto-infecção do Strongyloides stercoralis e caracterizada pelo encontro de larvas em múltiplos órgãos, incluindo o sistema nervoso central ABSTRACTStrongyloidiasis affects 30 million people in 70 countries. This enteral parasitosis is usually diagnosed using parasitological tests based on hydrotropism or thermotropism of larvae eliminated in feces, but these tests have been shown to have low sensitivity. In this study, antigenic extracts were tested by means of ELISA, immunoblotting and IFI, using filariform larvae of Strongyloides venezuelensis, a parasite of rodents that shows cross-reactions with Strongyloides stercoralis epitopes. Sensitivity of 89, 85 and 57% for the ELISA reaction and 100, 100 and 96% for immunoblotting with the SAL, ZWIP and ZW antigens, and specificity of 90, 60 and 81% for ELISA and 96, 92 and 91% for immunoblotting with the same antigens, were found in these assays. . Além disso, a diferenciação morfológica entre larvas de Strongyloides e as de ancilostomídeos exige técnicos experientes. O aperfeiçoamento dos métodos para diagnóstico sorológico representa um avanço na determinação da infecção em populações de risco como: crianças, gestantes, imunossuprimidos; e nos casos de infecções leves, possibilitando a indicação do tratamento específico 3 8 aumentando e melhorando assim a sobrevida de pacientes acometidos pela estrongiloidíase disseminada. Uma importante vantagem dos testes imunodiagnósticos, em relação aos parasitológicos, é que eles não dependem do nível de excreção larval 15 . Uma das principais limitações em se desenvolver testes sorológicos mais sensíveis e específicos é a dificuldade em obter quantidades suficientes de antígenos, que permitam seu Key

SUMMARYUsing an elevated plus maze apparatus and an activity cage, behavioral changes in Rattus norvegicus concomitantly infected by Toxocara canis and Toxoplasma gondii were studied, during a period of 120 days. Rats infected by Toxocara canis or Toxoplasma gondii showed significant behavioral changes; however, in the group coinfected by both parasites a behavioral pattern similar to that found in the group not infected was observed thirty days after infection, suggesting the occurrence of modulation in the behavioral response.

SUMMARYThe immune response expressed by IgG antibodies in BALB/c mice experimentally infected with Toxocara canis, was studied with the aim of verifying the possible in vivo cross-reactivity between antigens of T. canis and other parasites (Ascaris suum, Taenia crassiceps, Schistosoma mansoni, Strongyloides venezuelensis and Toxoplasma gondii). Experiments included three groups of mice: one infected only by T. canis, another with one of the other species of parasites and a third concomitantly infected with T. canis and the other species in question. Animals were bled by orbital plexus at 23, 38 and 70 days post infection (p.i.). Sera were analyzed for anti-Toxocara antibodies by ELISA and Immunoblotting, using excretion-secretion antigens (ES), obtained from culture of thirdstage larvae of T. canis. For all experiments a control group comprised by ten non-infected mice was used. Only in the case of A. suum infection, in these experimental conditions, the occurrence of cross-reactivity with T. canis was observed. However, in the case of co-infection of T. canis -S. mansoni, T. canis -S. venezuelensis and T. canis -T. crassiceps the production of anti-Toxocara antibodies was found at levels significantly lower than those found in mice infected with T. canis only. Co-infection with S. mansoni or S. venezuelensis showed lower mortality rates compared to what occurred in the animals with single infections. Results obtained in mice infected with T. canis and T. gondii showed significant differences between the mean levels of the optical densities of animals infected with T. canis and concomitantly infected with the protozoan only in the 23 rd day p.i.