In accordance with its clinical manifestations, this disease at the initial and intermediate stages, belongs to the categories of "wen bing" (seasonal febrile disease) and "yi bing" (epidemic disease) in TCM. The disease at later stage is similar to "acute tuberculosis". It is caused by unclean copulation, perverse behavior or contact with epidemic pathogenic factor. When healthy qi is insufficient, the epidemic pathogenic factor would seize a chance to attack the human body and therefore AIDS occurs. As the pathogenic factor is extremely serious, it may directly attack yingfen and xuefen upon the onset of the disease. The incubation period of the disease is long and the disease is terribly serious and lingering. After the seasonal febrile syndrome presents, lung qi and lung yin are often damaged and then the spleen, heart, liver, and kidney are involved with appearance of defeciency syndrome.