Aside from bats harbouring H17N10 and H18N11 subtypes10, wild waterfowl are considered to be the main reservoir for IAV, harbouring all viruses with the 16 HA and 9 NA subtypes associated with influenza in birds and which are the source of influenza viruses that are transmitted to other animal species8, 9. The gene discussed is XK; the disease is influenza.