Seroprevalence of Toxocariasis in Children with Urticaria: A Population-based Study.

Objective: This study described the prevalence of IgG class antibodies against Toxocara spp. and their association with urticaria in 2- to 12-year-old children. Methods: This population-based cross-sectional study was conducted between May 2012 and September 2014. The study sample comprised 168 children. Blood samples were collected to verify the presence of toxocariasis by using ELISA to detect IgG antibodies. The guardians of the children were interviewed to characterize the presence or absence of other diseases, such as urticaria. Results: The presence of urticaria was observed in 38% of participants. The seroprevalence of toxocariasis in this population was 16%. This study confirmed a positive association between urticaria and positive serology for Toxocara and a negative independent association with canine contact and the number of household residents. Conclusions: There are no previous reports in the literature of a population-based study that correlates the presence of urticaria with serology for toxocariasis.

Serosurvey of anti-Toxocara canis antibodies in people experiencing homelessness and shelter workers from São Paulo, Brazil.

BACKGROUND: Despite being one of the most prevalent helminth parasitic zoonoses worldwide and particularly in socioeconomically vulnerable populations, toxocariasis remains to be fully investigated in persons experiencing homelessness. Accordingly, the present study has aimed to assess the seroprevalence and associated risk factors of Toxocara spp. exposure in persons experiencing homelessness and shelter workers from a day-shelter in São Paulo city, Brazil. METHODS: Anti-Toxocara IgG antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Univariable and multivariable logistic regression models were performed to assess the risks for toxocariasis. RESULTS: Overall, anti-Toxocara IgG antibodies were detected in 89/194 (45.9%, 95% CI: 39.0-52.9%) persons experiencing homelessness, twice as high (OR = 2.2; 95% CI = 1.245-3.873; P = 0.0089) than the frequency of 22/79 (27.8%, 95% CI: 19.2-38.6) in shelter workers. College education was the only protective factor for Toxocara spp. exposure (OR: 0.23; P = 0.018) revealed by logistic regression. CONCLUSIONS: Although indicating a multifactorial origin of toxocariasis, the present study has assessed a highly vulnerable population with high disease risks and premature death. Thus, the living conditions of the homeless population have influenced the high prevalence of anti-Toxocara antibodies verified here compared with domiciled shelter workers. Despite being less exposed, shelter and other outdoor workers may present an occupational risk to toxocariasis. Future studies should establish whether such environmental exposure might occur in persons experiencing homelessness in other regions worldwide.

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

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

Epidemic of unilateral panuveitis in children from Brazilian Amazonia: clinical and etiological aspects in seven patients.

OBJECTIVES: To describe clinical presentation and results of diagnostic and therapeutic procedures in seven children from an epidemic of panuveitis in the Brazilian Amazonia, as well as environmental analysis and etiological aspects involved. METHODS: Patients underwent full pediatric and ophthalmic examinations, B-scan, ultrasound biomicroscopy, and serological tests. Ocular samples were thoroughly analyzed, including two enucleation specimens. Environmental investigation encompassed water, soil, and river fauna. RESULTS: All patients had bathed in the waters of a regional river, the Araguaia. Six of them presented with intermediate uveitis, with snowbanking. Five had cataract and four showed inferior endothelial opacity, with localized anterior synechiae. One showed total leukoma, with flat anterior chamber. Only two had active uveitis, one of them with anterior chamber nodule. Serology revealed high prevalence of anti-Toxocara canis immunoglobulin G (IgG) antibodies. In three cases, vitreous and lens samples disclosed spicules of freshwater sponges Drulia uruguayensis and D. ctenosclera, also detected in the waters of the river. CONCLUSION: Freshwater sponge spicules could be potential new etiological agents of ocular pathology, but further studies are needed, considering the heterogeneity of the ocular lesions and results of serological and environmental studies.

Seroprevalence Brazil.

This chapter presents an overview of the seroprevalence of toxocariasis in Brazil and discusses how this zoonosis is studied, diagnosed, and treated in the Brazilian population. Toxocariasis in humans has a high prevalence in several regions of Brazil; however, this disease is neglected because of lack of knowledge, non-specific clinical signs, and difficult diagnosis. Most studies conducted in Brazil have estimated the prevalence of toxocariasis, i.e., the number of people who presented the disease at any given time. However, a few studies have determined disease incidence (number of new cases in a population at risk) and identified risk factors for Toxocara canis infection. Despite the high seroprevalence, the Brazilian population is not well aware of toxocariasis. Thus, the need of the hour is to raise awareness about this parasitic infection because of its worldwide distribution and potential health risk.

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

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

[Antischistosomal activity of artemether in experimental Schistosomiasis mansoni]. / Atividade antiparasit ria do artemether na esquistossomose mans nica experimental.

OBJECTIVE: To evaluate the effect of intramuscular injection of artemether in mice experimentally infected with Schistosoma mansoni, at the time of infection, during schistosomula maturation and after the beginning of egg-laying. METHODS: Eighty adult females Balb/c mice were divided into 8 groups with 10 animals each. Seven groups were infected with S. mansoni using 60 cercariae for each animal, inoculated subcutaneously, and the remaining group was maintained without infection. Among the seven infected groups, six were treated with artemether, according to the following schedule: three groups received doses of 100 mg/kg on days 0, 20 or 60 after inoculation of the cercariae; the other three received 50 mg/kg of artemether, also on days 0, 20 or 60. At the end of the 9th, 10th and 11th weeks after infection all the mice infected with S. mansoni were submitted to fecal examination using the Kato-Katz technique. On the 80th day of the experiment, the surviving animals were sacrificed and submitted to perfusion of the portal system in order to recover the worms. Body, liver and spleen weights of each animal were determined at that time. RESULTS: A reduction in egg-laying and the number of worms recovered was observed in mice treated with artemether (50 or 100 mg/kg) on the 20th day after infection. The decrease in the number of worms was more notable among S. mansoni females. A significant decrease in liver and spleen weights was also seen on the 20th day among animals treated with 50 or 100 mg/kg of artemether and also among those that received the drug at a dose of 50 mg/kg 60 days after infection. CONCLUSIONS: Evidence of the antischistosomal activity of artemether was shown, even at a dose of 50 mg/kg, when the drug was administered during the schistosomula maturation period in the portal system of the vertebrate host.

Seroprevalence of Toxocara spp. in children with atopy.

BACKGROUND: Epidemiological studies around the world suggest that infection with Toxocara spp. can contribute to the development or worsening of atopic diseases, especially in children. This study investigated the seroprevalence of toxocariasis in atopic children treated at the pediatric clinic of the Federal University of Uberlândia Clinical Hospital, identifying possible relationships with risk factors. METHODS: The study was conducted between November 2011 and March 2013. Blood samples were collected from 173 children aged 6 to 15 years, who were first subjected to clinical exams and then to a skin-prick test to determine the presence or absence of atopy. Risk factors for toxocariasis were analyzed based on a questionnaire. Serum samples were tested for the presence of IgG antibodies to Toxocara spp. by means of enzyme-linked immunosorbent assay. RESULTS: The seroprevalence of Toxocara spp. was 19.6% (24/122) in atopic children and 15% (8/51) in non-atopic children, with no statistical difference. No significant association was found between infection and possible risk factors in atopic and non-atopic children. CONCLUSIONS: Although no statistical association was found between human toxocariasis and atopy, this study revealed a high seroprevalence of Toxocara spp. in children that may indicate environmental contamination with the parasite's eggs in the area where these children live.

[Evaluation of the humoral immune response to Strongyloides venezuelensis antigens]. / Avaliação da resposta imune humoral frente a antígenos de Strongyloides venezuelensis.

Strongyloidiasis 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.

Avaliação da resposta imune humoral frente a antígenos de Strongyloides venezuelensis / Evaluation of the humoral immune response to Strongyloides venezuelensis antigens

A estrongiloidíase afeta 30 milhões de pessoas em 70 países. Usualmente, o diagnóstico dessa enteroparasitose é realizado por testes parasitológicos baseados no hidro termotropismo das larvas eliminadas nas fezes, porém esses têm se mostrado pouco sensíveis. Neste trabalho, extratos antigênicos foram testados pelas técnicas de ELISA, Immunoblotting e IFI, utilizando larvas filarióides de Strongyloides venezuelensis, parasita de roedores, que mostram reação cruzada com epítopos de Strongyloides stercoralis. Sensibilidade de 89, 85, 57 por cento para a reação de ELISA e de 100, 100 e 96 por cento, para o Immunoblotting com os antígenos SAL, ZWIP e ZW, e especificidade de 90, 60 e 81 por cento para o ELISA e 96, 92 e 91 por cento para o Immunoblotting para os mesmos antígenos, foram encontradas nestes ensaios.

Strongyloidiasis 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 percent for the ELISA reaction and 100, 100 and 96 percent for immunoblotting with the SAL, ZWIP and ZW antigens, and specificity of 90, 60 and 81 percent for ELISA and 96, 92 and 91 percent for immunoblotting with the same antigens, were found in these assays.

Anti-helmínticos na toxocaríase experimental: efeito na recuperação de larvas de Toxocara canis e na resposta humoral / Anthelmintics in experimental toxocariasis: effects on larval recovery of Toxocara canis and on immune response

Estudou-se a recuperação de larvas na fase crônica de camundongos infectados por Toxocara canis, bem como a presença de anticorpos anti-Toxocara após tratamento com ivermectina, mebendazol ou tiabendazol, durante cinco dias consecutivos. Os animais foram sangrados pelo plexo retroorbitário entre 30 e 270 dias após a infecção (DPI). Os soros foram processados pela técnica de enzyme linked immunosorbent assay (ELISA) para pesquisa de anticorpos da imunoglobulina da classe G (IgG), utilizando antígeno ES de T. canis. Aos 270 DPI, os animais foram sacrificados para recuperação de larvas no sistema nervoso central, no fígado, nos pulmões e músculos. Os resultados do teste imunoenzimático indicam que, aos 20 dias após tratamento (50 DPI), o nível de anticorpos anti-Toxocara IgG aumentou nos três grupos tratados, mantendo-se elevado ao longo do experimento até o 270º DPI. Em relação aos animais infectados e não-tratados, observou-se decréscimo significativo no número de larvas recuperadas nos animais dos três grupos tratados, não se conseguindo a cura parasitológica. Com este estudo conclui-se que as três drogas utilizadas no experimento têm eficácia similar.

Atividade antiparasitária do artemether na esquistossomose mansônica experimental / Antischistosomal activity of artemether in experimental Schistosomiasis mansoni

OBJETIVO: Avaliar o efeito da administraçäo intramuscular de artemether a camundongos infectados experimentalmente por Schistosoma mansoni no momento da infecçäo, durante a maturaçäo dos esquistossômulos e após iniciada a oviposiçäo. MÉTODOS: Oitenta camundongos Balb/c, fêmeas adultas, foram divididos em oito grupos com 10 animais cada. Sete grupos foram infectados por S. mansoni empregando-se 60 cercárias para cada animal, inoculadas por via subcutânea; o grupo restante foi mantido sem infecçäo. Entre os sete grupos infectados, seis foram tratados com artemether, segundo o seguinte esquema: três grupos receberam dose correspondente a 100 mg/kg no dia 0, 20 ou 60 após inoculaçäo das cercárias; os demais receberam 50 mg/kg de artemether, no mesmo período que os lotes anteriores. Da 9ª, 10ª e 11ª semanas após infecçäo os camundongos infectados por S. mansoni foram submetidos a exames de fezes pela técnica de Kato-Katz. No 80º dia do experimento, os animais sobreviventes foram sacrificados e submetidos à perfusäo do sistema porta para recuperaçäo de vermes. Determinaram-se, nessa ocasiäo, os pesos corporal, hepático e esplênico de cada animal. RESULTADOS: Observou-se queda na oviposiçäo e no número de vermes recuperados entre os camundongos tratados com artemether (50 ou 100 mg/kg) no 20º dia após infecçäo. A diminuiçäo do número de vermes foi mais expressiva no caso de fêmeas de S. mansoni. Verificou-se, ainda, diminuiçäo significativa nos pesos hepático e esplênico entre os animais tratados com 50 e 100 mg/kg de artemether no 20º dia e também entre os que receberam a droga na dose de 50 mg/kg 60 dias após infecçäo. CONCLUSÕES: Ficou evidenciada a atividade anti-Schistosoma do artemether, mesmo ao se empregar dose correspondente a 50 mg/kg, quando a droga foi administrada durante o período de maturaçäo dos esquistossômulos no sistema porta do hospedeiro vertebrado.