Viral challenge and sample collections in pregnant and non-pregnant mice.

Four groups of the mice (12-13 mice/group) were intranasally inoculated with wild type or mutant viruses. Four groups of mice were sampled at day 3 and 6 post-infection, respectively. The experiment was duplicated. This table showed the total numbers of mice in these two experiments.将四组小鼠（每组12~13只）经鼻接种野生型（wild type）或突变型病毒（mutant viruses）。分别于感染后第3天和第6天对该四组小鼠进行采样。本实验开展了两次重复操作。本表格展示了这两次重复实验中小鼠的总数量。