Other in vivo study, on the local innate immune response in bronchoalveolar lavage fluid (BALF) cells of pigs singly inoculated with PRRSV or co-inoculated with PRRSV and IAV revealed that infection with PRRSV alone or with IAV affected the expression of IFN-α and delayed the onset of IFN-γ expression. The gene discussed is IFNA1; the disease is infection.