Residual Pathogenic Factor
One of the main conditions leading to post-viral fatigue is that of "residual pathogenic factor". If
external Wind invades the body and is not cleared properly, or if the person fails to rest during
an acute invasion of Wind, the pathogenic factor may remain in the Interior (usually either as
Heat or Damp-Heat). Here, on the one hand, it continues to produce symptoms and signs, or on
the other, predisposes the person to further invasions of exterior pathogenic factors because it
obstructs the proper spreading and descending of Lung-Qi. Moreover, it will also tend to weaken
Qi and/or Yin, establishing a vicious circle of pathogenic factor and deficiency.
Apart from Heat itself, Damp-Heat is a very frequent residual pathogenic factor after a febrile
disease. There are two main reasons for this. First of all, in the course of a febrile disease, the
ascending and descending movements of Spleen and Stomach are upset. Thus, because
Stomach-Qi cannot descend, turbid fluids are not transformed, and because Spleen-Qi cannot
ascend, the clear fluids cannot be transformed: this leads to the formation of Dampness.
Secondly, Heat burns the body fluids which can then condense into Dampness. Once formed,
Dampness is rather self-perpetuating. In fact, Dampness impairs the Spleen transformation and
transportation which in itself leads to more Dampness being formed, thus establishing a vicious
circle.
It is therefore important to take special care and rest during or immediately after an invasion of
an exterior pathogenic factor. At this time one should rest more than usual, take care not to catch
cold, eat simple and bland food and abstain from sex altogether. If not, the pathogenic factor will
not be cleared properly and will remain inside, usually either as Heat or Damp-Heat.
Antibiotics are one of the most common causes of residual pathogenic factor in our society.
Whilst they do destroy bacteria, from the point of view of Chinese Medicine they tend to "lock"
the pathogenic factor in the Interior and do not release the Exterior in the beginning stages of an
exterior invasion, nor clear Heat or resolve Phlegm in the later stages. Dr J. H. F. Shen uses an
excellent simile to illustrate the effect of antibiotics. If we heard a burglar entering our house in
the middle of the night, we could react in one of two different ways: either we could get up,
make a noise and scare the burglar off; or, if we had a gun, we could shoot the burglar dead.
Killing the burglar clearly gets rid of him but at the cost of creating a bigger problem: the
immediate difficulty of being lumbered with a dead body in the house, and the long-term
difficulty of trouble with the law. Thus the first option is clearly preferable: the burglar leaves
the house before having the opportunity of stealing anything, our porperty and life are safe and
that is the end of the problem. If we take the burglar to symbolize the invasion of an external
pathogenic factor, the first option corresponds to the way Chinese medicine works: it gets rid of
the pathogenic factor without harming the body. The second option corresponds to the way
antibiotics work: they kill the bacteria, but they do not get rid of the pathogenic factor. The body
is therefore lumbered with a residual pathogenic factor (the "dead burglar's body"). Furthermore,
Chinese medicine gets rid of the pathogenic factor by raising the immune response and
strengthening the body resistance. Although antibiotics kill the harmful bacteria, they inevitably