Type III interferons (IFN) are the major player of mucosal immunity in the intestines of human and mouse.29 IFN lambda-1 (IFNL1) and IFNL3 were highly induced in human intestinal organoids upon viral infections.21,26 We first determined the sequences of horseshoe bat type III IFNs using RACE PCR. This evidence concerns the gene IFNA1 and viral infectious disease.