The respiratory tract is an important portal of entry for respiratory viruses . 呼吸道是呼吸道病毒入侵的重要门户。
2.
Some such as influenza viruses and rotaviruses produce disease at the portal of entry and have no necessity for further systemic spread 一些病毒如流感病毒和轮状病毒在入侵的部位引起疾病而不需要系统的播散。