For example, PEDV infection in suckling pigs leads to the increased serum IFN-α in the early stages (Annamalai et al., 2015); In the early period of infection, a modest increase in the level of IFN-α and IFN-β can be detected in the lungs of SARS-CoV-infected BALB/c mice (Chen et al., 2010). This evidence concerns the gene IFNA2 and infection.