If the skin is not infected after 12 days of being scratched by a rat, there is basically no danger, because the incubation period of plague takes about 2 to 8 days. The incubation period can be extended to 9 to 12 days for those who have been vaccinated. Therefore, it is generally safe to go 12 days without symptoms of infection such as fever, chest pain, bleeding and other symptoms. In addition, the incubation time of a disease like plague is closely related to the patient’s body resistance. If an individual has a low level of physical fitness or has a more serious medical condition of their own, then they can easily be infected by the plague virus and the onset of the plague will become quicker. Whenever a rat catches, bleeds, scratches, or breaks the skin, vaccination is required in this case, and in the absence of vaccination, symptoms associated with the plague will appear. Lobbing a large amount of foamy bloody sputum or bright red sputum; shortness of breath and rapid presentation of dyspnea and cyanosis, and so on. Clinical due to individual differences, the condition is different, each person’s performance is different, it is recommended that the occurrence of scratched epidermis by rats timely medical treatment, standardized treatment, to avoid delaying the condition.