Anterograde transmission: refers to the pathological changes starting from Wei points, followed by Qi points, Ying points and Blood points. It embodies the process of pathogenic factors from the outside to the inside, from the outside to the deep, step by step, from light to heavy, from real to virtual.
Reverse transmission: refers to the direct infiltration of pathogenic factors into Yingwei and blood without going through the stages of qi. In fact, "reverse transmission" is only a special type in the law of "true transmission", but the condition is more acute and serious.
In addition, due to the particularity of pathogenic factors and body response, the spread and change of epidemic febrile diseases do not conform to the above laws. If there is no Wei-fen syndrome at the beginning of the disease, but you can see Qi-fen syndrome or Ying-fen syndrome; Defending qi is not limited, but also qi is also qi, resulting in "defending qi disease"; The syndrome of qi differentiation still exists, and there is another syndrome of camp differentiation or blood differentiation, which is called "double burning of qi and camp" or "double burning of qi and blood". Therefore, the transmission and change of symptoms in the process of epidemic febrile diseases are more complicated.