Sero-epidemiology of toxocariasis in a rural settlement in São Paulo state, Brazil

Abstract

The seroprevalence of Toxocara canis and risk factors for infection with this parasite were explored in a rural settlement in São Paulo state, Brazil. Total IgA and IgE levels in 79 subjects were determined by turbidimetry and chemiluminescence, respectively. Total counts of leucocytes and erythrocytes and differential counts of leucocytes were made by flow cytometry. ELISA for the detection of anti-Toxocara IgG, IgA and IgE were standardized using Toxocara excretory-secretory antigens (TES) obtained from the cultured second-stage larvae of T. canis. Seventeen (21.5%) of the subjects were found positive for anti-Toxocara IgG, with no significant differences in such seropositivity with age or gender. Thirty (38%) of the subjects showed eosinophilia and 70 (89%) had elevated levels of total IgE. Among the 17 subjects found seropositive for anti-Toxocara IgG, the percentage of leucocytes represented by eosinophils (P=0.0069) and total levels of IgE (P=0.0452) were positively correlated with the levels of anti-TES IgE. Although anti-TES IgA was detected in 10 (59%) of the subjects, there was no significant correlation between the levels of total IgA and those of Toxocara-specific IgA. Only one of the 17 subjects found positive for anti-Toxocara IgG had attended a secondary school and all but two belonged to households with monthly incomes of <U.S.$100. In the study community at least, seropositivity may be related to poor living standards and lack of basic sanitary conditions. The presence of anti-Toxocara IgE and IgA may facilitate the diagnosis of toxocariasis and may well be useful for monitoring the success of treatment.

Environmental contamination by Toxocara spp. Eggs in a rural settlement in Brazil

“…Josimo in the same area 15 . However, the soil contamination was evaluated by these authors in plots where at least one inhabitant had shown anti-Toxocara spp.…”

“…When soil samples were checked in 24 plots where at least one human being was considered seropositive, embryonated Toxocara spp. eggs were found in five (21%) of the investigated plots 15 .…”

Seroprevalence of toxoplasmosis, toxocariasis and cysticercosis in a rural settlement, São Paulo State, Brazil

“…Concomitantly, the country has experienced increasing migration of people from cities to rural areas, most of them in poor living conditions and lacking sanitary infra-structure. 14,15 Emerging and re-emerging parasitic zoonoses such as toxocariasis, toxoplasmosis, and cysticercosis remain incontrollable in some regions. 6,8,16 Improved and new serological and molecular tests can represent an important tool in the attenuation of morbidity and mortality due to parasitic zoonoses, especially in developing countries.…”

“…These settlements are characterized by poor living conditions, deficient potable water supplies and sanitary facilities and could be a source for parasitic infections. 14,15 The Pontal of Paranapanema is one of the poorest and most undeveloped regions of the Sã o Paulo state, in southeastern Brazil. This region contains the highest density of rural settlements in the country.…”

“…This region contains the highest density of rural settlements in the country. [14][15][16] We have previously determined the seroprevalence of toxocariasis/cysticercosis in this region in both an old settlement (20 years) and in a recently formed settlement (2 years). [14][15][16] The aim of this study was to determine the seroprevalence of Toxocara spp., T. gondii, and T. solium metacestode infection and explore some risk factors in people living in a settlement in Pontal of Paranapanema, São Paulo, Brazil.…”