Similar findings were observed previously during subclinical infection with H1N1 influenza virus in pigs.20 In H1N1 model, only Hp and SAA were significantly induced while concentration of CRP and Pig-MAP remained generally unchanged.20 Although in half of the infected pigs the concentration of CRP tended to increase at 1 dpi, it was not of statistical significance. This evidence concerns the gene CRP and infection.