Seroprevalence of Toxoplasma gondii infection in yaks (Bos grunniens) on the Qinghai-Tibetan Plateau of China.

Toxoplasma gondii (T. gondii), a zoonotic parasite infects almost all warm-blooded animals and causes significant economic losses. To date, however, it is still unclear whether yaks from the Qinghai-Tibetan plateau of China are exposed to T. gondii. On the present study, a survey was conducted for the first time, to investigate the seroprevalence of T. gondii infection in yaks (Bos grunniens) on the Qinghai-Tibetan Plateau (Qinghai, Tibet, Hongyuan area of Sichuan province). A total of 905 and 736 serum samples were collected from yaks in these areas in 2012 and 2013, respectively and assayed for T. gondii antibodies by an indirect hemagglutination test (IHA). The results showed that seroprevalence on plateau was 21.7% and 29.1% in 2012 and 2013, respectively with the prevalence of 22.4%, 19.4% and 25.5% in 2012 for Qinghai, Tibet and Hongyuan of Sichuan, respectively and of 26.4%, 27.0% and 33.7% for these three regions in 2013, respectively. The present survey indicated that the infection with T. gondii in yaks was widely spread in recent years on the plateau causing a high risk factor for animals and humans.