Age is a determinant factor in the susceptibility of domestic ducks to H5 clade 2.3.2.1c and 2.3.4.4e high pathogenicity avian influenza viruses

High pathogenicity avian influenza (HPAI) is a viral disease with devastating consequences for the poultry industry worldwide. Domestic ducks are major source of HPAI viruses in many Eurasian countries. The infectivity and vary depending on host factors. To assess factors influencing ducks, we compared pathobiology two (H5N1 clade 2.3.2.1c H5N6 2.3.4.4e) 5- 25-week-old ducks. Both caused mortality dose-dependent manner (10 4 , 10 6 8 EID 50 ) young By contrast, adult were infected but exhibited no due to either virus. Viral excretion was higher than adults, regardless strain. These findings demonstrate age-dependent 2.3.4.4e H5