Variations in levels of antibodies directed against HP-PRRSV and PCV2 in each experimentally infected group. (A) The antibody titer was significantly lower in the HP-PRRSV/PCV2 group than in the other groups. (B) The titer of PCV2 antibodies was significantly lower in the HP-PRRSV/PCV2 group than in the other three infected groups. The antibody titer was significantly higher in the PCV2 group than in the three coinfection groups. Error bars show the standard deviations. * indicates significantly higher or lower values. * p < 0.05, ** p < 0.01; and n.s., not significant.