CSF1 and infection: Compared with the negative group, the PEDV-QY2016 strains infection group had significantly increased the synthesis of interleukin (IL)-1 and macrophage colony-stimulating factor (M-CSF), that is, the IL-1 levels were significantly upregulated in nursery piglets at 24 hpi (Figure 2A), and the M-CSF significantly increased in neonatal piglets at 48 hpi (Figure 2B).