Macrophages of the bat Myotis myotis and the domestic mouse (Mus musculus) when stimulated with polycytidylic acid, Poly (I:C) (ligand of toll-like receptor 3 – TLR3) mimicking a virus infection, or lipopolysaccharides from bacterial membrane (ligands of toll-like receptor 4 - TLR4) showed high levels of mRNA of IFNβ, tumor necrosis factor (TNF) and IL-1β. The gene discussed is TLR4; the disease is viral infectious disease.