Seroprevalence of HEV in Tibetan swine. A, the positive rate of anti-HEV IgM and IgG antibodies in serum of Tibetan swine, China; B, the different of anti-HEV IgM antibody and anti-HEV IgG antibody positive rate between the gender in two cities; C, the different of anti-HEV IgG antibody positive rate between the gender in two cities.