Toxocara Prevalence in Soil and Humans in Vladivostok: A Long-term Study

Abstract

Background: Toxocariasis is a zoonotic parasitosis with worldwide distribution. Environmental contamination with Toxocara eggs is a main source of human infections. In Russia, particular in Vladivostok, knowledge regarding the current situation, including distribution and environmental contamination by Toxocara spp., is largely unknown. Objectives: The present study investigated environmental contamination with Toxocara spp. eggs, in soil samples collected from sandpits and public parks in Vladivostok, Russia during 23-month period. Methods: A total of 260 soil samples from sandpits and 155 samples from public parks were collected during July 2015 to December 2017. Soil samples were tested by sedimentation/flotation technique. Seroprevalence of Toxocara antibody in human was analyzed using Toxocara canis IgG ELISA assay. Results: Overall, the annual prevalence of Toxocara spp. in sandpits varied between 20% - 23% the annual prevalence of Toxocara spp. in public parks varied between 25% - 42% in different years. The average number of Toxocara spp. varied from 0 to 220 eggs per 1 kg over the 3-years study period. The highest prevalence was registered in summer period. The significant correlation appeared between Toxocara spp. contamination rates in sandboxes and parks and the Toxocara prevalence in humans in 2016 year. Conclusions: Current study demonstrates that it is necessary to promote preventive public health measures to avoid soil contamination.