Seroprevalence and risk factors for Toxocara infection in children from an urban large setting in Northeast Brazil

Abstract

Objectives: This study aimed to standardize an "in house" immunoassay to detect anti-Toxocara IgG antibodies in human serum to estimate the seroprevalence of Toxocara infection, and to identify its potential risk factors in children living in poor areas of Salvador, a large northeastern Brazilian city.

Methods: Parents of 1309 children answered a questionnaire containing possible risk factor for acquisition of this infection. Blood was collected and the presence of anti-Toxocara IgG antibodies was detected by indirect ELISA using T. canis larval excretory-secretory antigens in sera previously absorbed with Ascaris lumbricoides antigens.

Results: Seroprevalence of Toxocara infection was 48.4%. Children's age, low maternal schooling, contact with dogs and cats, and household located in paved streets were shown to be risk factors for Toxocara infection.

Conclusions: The seroprevalence of Toxocara infection is high among children living in a poor urban setting of Brazil. The association of low maternal education with higher Toxocara infection supports studies showing that low socioeconomic status is a risk factor for the acquisition of this infection as a reflection of hygiene habits of the family. And both infected-dogs and cats may be involved in this parasite transmission in this children population.

Keywords: Children; Risk factors; Seroprevalence; Toxocara infection.

Fig. 1

In house immunoassay to detect anti-T. canis IgG and results of the tested sera: (A) 12% polyacrilamide gel electrophoresis of T. canis excretory/secretory larval antigens for stained with blue Cooumasie (a) molecular weight markers; (b–d), antigen amount of 0.1, 0.2, 0.4 and 0.8 μg/well respectively); (B) results ofthe absorption of the children sera with somatic antigen of adult A. lumbricoides in the presence of polyetilenglycol as described in Section 2; (C) determination of the ELISA cut-off for anti-T.canis IgG as described in Section 2 and (D) dispersion of the anti-T.canis IgG in serum samples of the study population. Numbers in x-axis represent each sample.