Due to its periodicity , unpredictability,calamity and durability, we the human have not had ways to accurately predict as well as effectively avoid a start of pandemic yet.

• 流感大流行有一定的周期性、不可预见性、灾害性、持久性,至今人类依然没有找到准确预见、避免一场新的流感大流行的良策。