HP and infection: Infection of sheep with P. multocida, the Gram-negative bacterium, increased the concentration of Hp (34-fold), SAA (7-fold), and Fb (2-fold) [87], while infection of sheep with Sarcoptes scabei (an arthropod, the itch mite) caused the elevation of the concentration of Hp (2-5-fold), AGP (10-fold), and Cp (2-5-fold).