Even in small amounts, the rabies virus can still be infected when it enters the bloodstream. The human body has an immune system, so if a small amount of rabies virus enters the bloodstream, it may be eliminated by the immune system, but it may also multiply and cause infection. Rabies is mostly contracted from rabid animals, bites, scratches, etc. A few can be transmitted through direct saliva contact with mucous membranes or skin wounds. Even if a very small amount of rabies virus is transmitted through the above channels, the patient’s failure to clean the wound in time or to receive rabies vaccination may result in the occurrence of rabies virus infection. However, in the case of a very small amount of rabies virus, it is also possible that after disinfection, infection will not normally occur and may be eliminated by the immune system. Therefore, once a patient has been infected by an animal suspected of carrying the rabies virus, it is recommended that he or she should go to the hospital for rabies vaccination within 24 hours.