TLR2 recognizes many bacterial, fungal, viral, and certain endogenous substances, and is involved in activation of innate immunity [26, 27]; ADGRE1 is the marker gene for myeloid differentiation in pigs [28]; expression of CD163 is increased during infection with A. pleuropneumoniae [29] and H. parasuis [30]; FAM111A plays a role in inhibiting viral genome replication [31]. Here, ADGRE1 is linked to infection.