Seroepidemiology, modifiable risk factors and clinical symptoms of Toxocara spp. infection in northern Iran.

Toxocariasis is one of the most important and widespread neglected tropical infectious diseases. We designed a cross-sectional study to assess the seroepidemiological aspects of toxocariasis among the general population in northern Iran. A total of 630 rural subjects were enrolled to participate in the study. The presence of anti-Toxocara immunoglobulin G (IgG) was tested using a commercially available enzyme-linked immunosorbent assay. A structured questionnaire was also used to evaluate the potential risk factors and related clinical signs/symptoms. The presence of anti-Toxocara IgG antibodies was detected in 148 of the 630 rural subjects (23.5% [95% confidence interval {CI} 21.8 to 25.1]). By multivariate analysis, age (odds ratio [OR] 2.89 [95% CI 1 to -8.3], p=0.04), eating improperly washed vegetables (OR 4.05 [95% CI 2.47 to 6.64], p<0.001), contact with dogs (OR 3.31 [95% CI 2.13 to 5.12], p<0.001) and exposure to soil (OR 3.56 [95% CI 2.13 to 5.13], p<0.001) were significantly associated with the seroprevalence of Toxocara. The clinical study also demonstrated that the seroprevalence of Toxocara infection was significantly associated with asthma (OR 3.78 [95% CI 1.63 to 8.75], p<0.001) and ophthalmic disorder (OR 1.83 [95% CI 1.04 to 3.21], p=0.034). The findings proved that residents of rural communities in tropical regions may be heavily exposed to Toxocara spp. We highly recommend more investigations in high-risk groups.