This study aimed to examine the host cell apoptosis in the tissues of Peking ducks infected with duck swollen head hemorrhagic dis-ease virus (DSHDV).The dynamic changes associated with apoptosis occurring in the internal tissues were evaluated at different time points postinoculation (PI) by performing hematoxylin and eosin (HE) staining,followed by light microscopy,terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay,and transmission electron microscopy (TEM).The results showed that DSHDV infection could induce apoptosis in host cells,including those of the bursa of Fabricius (BF),thymus,spleen,liver,intestinal tract,kidney,and esophagus.The apoptotic index (AI) values increased with time from 2 to 72 h PI,and the highest values were recorded at 72 h PI.Further,cell death due to classic necrosis was observed in the dying or deceased ducks after 72 h PI.In conclusion,host cell apoptosis can be induced by DSHDV and may play an important role in the pathogenesis of duck viral swollen head hemorrhagic disease (DVSHD).