Seroprevalence and B1 gene genotyping of Toxoplasma gondii in farmed European mink in the Republic of Tatarstan, Russia.

Toxoplasma gondii is a protozoan parasite that infects almost all species of mammals and birds, including fur-bearing animals. However, the prevalence of T. gondii among Russian fur-bearing animals is unknown. In this study, the seroprevalence of T. gondii in European mink in Russia was investigated. In total, 100, 119 and 61 serum samples were collected from a fur farm, located in the Republic of Tatarstan, Russia, in autumn 2016, 2017 and 2018, respectively. The seroprevalence of T. gondii in 2016, 2017 and 2018 was 32% (23.2%-42.2%, 95% confidence interval [CI]), 31.1% (23.1%-40.3%, 95% CI) and 41.0% (28.8%-54.3%, 95% CI), respectively. In total, 50 brain samples from 100 animals whose blood was sampled in 2016 were analyzed by PCR to detect T. gondii DNA. T. gondii DNA was detected in 14% (7/50) of the mink brain samples. To examine single nucleotide polymorphisms (SNPs) in the partial B1 gene, we sequenced an 836-bp fragment, which contains a few SNPs, from the detected T. gondii DNA. The sequences of the fragments were identical to those of two of the major lineages, Type II and Type III, but differed from that of the Type I lineage.