Presence of viral antigen in ducks infected with HP VN/1203/K and HP VN/1203/E virus.

AThe ducks with an asterix are obtained from the experiment described in Table 2. The ducks without an asterix are from the pathogenesis experiment.
BThe days pi reflect the mean time to death for the ducks with asterix or the time of euthanasia.
CNumber of samples positive for virus antigen as measured by immunohistochemistry. Scoring system: 1 = Antigen sparse, 2 = Antigen common, 3 = Antigen abundant.
DOnly 5 samples available.

A. 带星号的鸭子取自表2所述实验；未带星号的鸭子则来自发病机制实验。
B. 天数pi代表带星号鸭子的平均死亡时长，或其实施安乐死的时间。
C. 经免疫组织化学法（immunohistochemistry）检测呈病毒抗原阳性的样本数量。评分标准：1分表示抗原稀疏分布，2分表示抗原普遍存在，3分表示抗原大量富集。
D. 仅可获得5份样本。