The primary pathogens comprise of PRRSV, PCV2, IAV, ADV, and Mhp, acting as immunosuppressive or immunomodulatory agents in the host, while App attacks the phagocytic cells and impairs the defense mechanisms in the respiratory tract of the pig, thereby rendering it prone to secondary infections by other bacterial pathogens (such as Pm, Bb, Gps, and Ss) (1, 2). This evidence concerns the gene PRB1 and infection.