The virus used in Professor Zhang Zhiwei's experiment was extracted from Yang Ping's body. After being injected into Professor Zhang Zhiwei, it did not cause a high fever but maintained a continuous low-grade fever of around 38.2 degrees Celsius. The fever subsided in less than three days, and the body temperature returned to normal. This reaction, at most, is akin to a minor cold.
It seems that this new K virus is a compromise product after an encounter with Yang Ping's immune system and has already developed good adaptability.
However, it is strange that these viruses showed very weak performance inside Professor Zhang's body, completely lacking the ability to replicate on a significant scale, and were basically cleared out by the immune system in three to four days.