<i>Toxocara</i> Infection Seroprevalence and Its Relationship with Atopic Features in a General Adult Population

Abstract

Background: The relationship of helminth infection with atopy is controversial. Toxocariasis is the most common helminth infection in industrialized countries. The study aimed to investigate the association between Toxocara exposure and atopic features. Methods: The study is based on a cross-sectional survey of 463 subjects, randomly selected (stratified by decades of age) from a general adult population. Toxocara exposure was defined by the presence of serum Toxocara antibodies. Main outcome measures included total serum IgE levels, skin prick tests (SPT) to a panel of 13 relevant aeroallergens, specific IgE to aeroallergens (Phadiatop test), and respiratory symptoms evaluated by means of a questionnaire. Results: A total of 134 subjects (weighted proportion 28.6%, 95% CI 26.5–30.7%) showed Toxocara exposure. Pet ownership, rural habitat, farming, and low educational level were associated with Toxocara exposure. Toxocara exposure was associated with both positive SPT (particularly to mites) and positive specific IgE (Phadiatop test) after adjusting for potential confounders. The effect of Toxocara exposure on total serum IgE levels and blood eosinophil count was different in SPT-positive subjects and SPT-negative individuals. In SPT-negative individuals, Toxocara exposure was associated with an increase in both serum IgE levels and eosinophil counts, whereas an opposite trend was observed in SPT-positive individuals. Toxocara exposure was not associated with respiratory symptoms. Conclusions: In this adult population, Toxocara exposure is associated with allergic sensitization, particularly to mites. There is evidence of an intriguing interaction between Toxocara exposure and allergic sensitization for both total serum IgE levels and blood eosinophil counts.

Human Toxocariasis in Rural Brazilian Amazonia: Seroprevalence, Risk Factors, and Spatial Distribution

“…Male gender, for example, was suggested to be associated with both increased [27][28][29][30] and decreased 31 risk of infection, with some large studies showing no association between gender and risk. [32][33][34] Young age, 35 low socioeconomic status, 36 low parental education, 34,37 and poor sanitation 6 are additional factors contributing to Toxocara exposure in some communities. Dog ownership has been identified as a risk factor in several 11,27,35,[37][38][39] although not all 40 studies of urban and rural populations.…”

“…[32][33][34] Young age, 35 low socioeconomic status, 36 low parental education, 34,37 and poor sanitation 6 are additional factors contributing to Toxocara exposure in some communities. Dog ownership has been identified as a risk factor in several 11,27,35,[37][38][39] although not all 40 studies of urban and rural populations. None of these known risk factors, except for young age, was significantly associated with Toxocara exposure in our population (P values between 0.338 and 0.921 in multivariate models).…”

Toxocariasis: visceral larva migrans in children

“…O fato de possuir cão na casa foi um fator de risco para sorologia positiva em vários estudos 17,19,20,23,24,30,31,[34][35][36] . Alguns autores não encontraram associação entre os donos de cães 17 e a frequência de infecção por Toxocara, o que poderia ser explicado pelas medidas de higiene adequadas adotadas pelos adultos.…”

“…Em Brasília (DF), foi encontrada soropositividade para T. canis de 21,8% em amostras colhidas em laboratório de hospital público e de 3% em crianças de classe média, atendidas em laboratório privado 44 . Alguns estudos mostraram associação entre morar em zona rural e toxocaríase 17,20,35,45 .…”

“…Em outros estudos brasileiros, a idade prevalente foi acima de 5 anos 13,31,33,55 . Em estudos caso-controle, não foi encontrada diferença significativa em relação à idade 17,29,33,[35][36][37]58 .…”