疫情消长即传染病发病上升和下降是疫情统计分析中的一项重要内容,采用两期比较计算发病上升和下降有利于分析了解传染病的发生、发展、上升下降的规律。目前大多数疫情分析采用两期病例数直接计算传染病发病升降,发病百分比%= The rise and fall of epidemic situation, ie the rising and falling of infectious diseases, is an important part of the epidemiological analysis. The comparison and calculation of the rising and falling incidences of the two phases are helpful to analyze and understand the law of the occurrence, development, rise and fall of infectious diseases. At present, most epidemic situation analysis using two cases of direct calculation of the rise and fall of the incidence of infectious diseases, the incidence of% =