Molecular detection and genotyping of Toxoplasma gondii in free-ranging pigs in Northeastern China

Pig is the well-known intermediate host of T. gondii, a ubiquitous and obligate intracellular zoonotic pathogen. However, information about prevalence and genotypes of T. gondii infection in free-ranging pigs is scarce. Therefore a total of 186 hilar lymph nodes specimens were collected from free-ranging pigs from rural regions from Jilin (n = 119) and Liaoning (n = 67) provinces, northeastern China, and were investigated from T. gondii infection by semi-nested PCR of the B1 gene. Positive testing samples were genotyped by using polymerase chain reaction followed by restriction-fragment length polymorphism technology (PCR-RFLP) applied to 11 loci. The overall prevalence of T. gondii in investigated free-ranging pigs was 18.3% (34/186), with 16.4% (11/67) in Liaoning Province and 19.3% (23/119) in Jilin Province. Moreover, two genotypes, namely ToxoDB #9 and ToxoDB #10, were detected in investigated pigs. The present study showed a high T. gondii prevalence in free-ranging compared to farmed pigs as reported in previous studies by others, raising a major public health concern. It is essential to establish efficient strategies to prevent and control T. gondii infection in free-ranging pigs, other animals and humans in investigated regions.