Detection of Toxoplasma gondii oocysts in soils in Northwestern China using a new semi-nested PCR assay (Epidemiologic Perspectives & Innovations)

Background: Toxoplasma gondii is a zoonotic pathogen that can infect a range of animals and humans. Ingestion of T. gondii oocysts in soil is a significant transmission route for humans and animals acquiring toxoplasmosis. In the present study, we developed a new semi-nested PCR method to determine T. gondii oocysts distribution in soils in northwestern China. Results: The one tube semi-nested PCR assay was developed to detect the oocysts of T. gondii in soil, targeting the repetitive 529?bp fragment of T. gondii genomic DNA. Then a total of 268 soil samples, including 148 samples from Gansu Province and 120 samples from Qinghai Province, northwestern China, were examined by the semi-nested PCR method. One third of the positive samples were sequenced. The sensitivity of the semi-nested PCR assay was 102? T. gondii oocysts in 5?g soil sample. Investigation of soil samples from northwestern China showed that 34 out of 268 soil samples (12.69%) were T. gondii positive. Sequences of the partial 529?bp fragments varied from 0?1.2% among the sequenced samples. The prevalence of T. gondii oocysts in soil from cities (24/163) was slightly higher than that in soils from pasturing areas (10/105) (P?=?0.21). Among the different regions in cities, the prevalence of T. gondii oocysts in soils from parks was 14.15%, whereas that in soils from schools was 19.05%. Conclusions: The present study firstly reported the prevalence of T. gondii oocysts in soils in northwest China using a novel semi-nested PCR assay, which provided baseline data for the effective prevention and control of toxoplasmosis in this region.