First Report on Toxoplasma gondii Seroprevalence in Free-Ranging Pigs in Northeastern China.

Introduction: Toxoplasma gondii is the pathogen of toxoplasmosis, which affects a wide range of animal species and humans.
Materials and Methods: In the present study, a serological investigation was undertaken to determine the seroprevalence of T. gondii infection in free-ranging pigs in northeastern China. A total of 806 serum samples were collected from free-ranging pigs in 6 cities in Liaoning, Jilin, and Heilongjiang Provinces.
Results: Among them, 163 serum samples (20.22%) were detected T. gondii positive by indirect hemagglutination test (IHA). In each administrative district, the prevalence ranges from 12.99 to 22.22%. It was found that sample collection year and season were associated with T. gondii infection. Samples collected in 2015 and 2016 had had higher positive rate compared to those collected in 2017. Samples collected in summer and autumn also have higher positive rate than those in winter.
Conclusion: This is the first report on T. gondii seroprevalence in free-ranging pigs in northeastern China, which adds the epidemiological data of T. gondii infection in free-ranging pigs in China. These results indicated that free-ranging pigs in Liaoning, Jilin, and Heilongjiang Provinces are exposed to T. gondii, which is a significant threat to local pig industry as well as public health. It is necessary to take relevant comprehensive measures to prevent and control T. gondii infection in free-ranging pigs in these regions.