After being bitten by a mouse, the wound will be locally red, swollen, painful and even feverish, and in serious cases, it may cause lymphadenitis or cellulitis, swelling and pain in the lymph nodes. If a rat bite requires prompt disinfection, squeeze out as much dirty blood as possible, rinse with plenty of water and then disinfect the skin. Rats can carry a variety of infectious agents, such as Mycobacterium plague, hantavirus, and rat bite fever spirochetes. It is necessary to pay attention to whether there are clinical manifestations of the following diseases and promptly visit the hospital: 1. Plague: If infection with S. Typhimurium may lead to plague, chills and high fever may easily appear, which may be accompanied by nausea, vomiting, headache and pain in the extremities, flushing, and conjunctival congestion. Significant redness, swelling, heat and pain of lymph nodes and surrounding tissues, or shortness of breath, cyanosis, coughing and other symptoms may occur, as well as confusion, slurred speech, bleeding in the cavity, blood pressure drop, etc. In serious cases, multi-organ failure, or even life-threatening; 2. Renal syndrome hemorrhagic fever: rats are the main infectious source of renal syndrome hemorrhagic fever, and the pathogen is hantavirus. Often fever accompanied by generalized aches and pains, headache, lumbago and orbital pain, conjunctival congestion or hemorrhage, eyelid edema, skin mucosal petechiae or petechiae, face, neck and chest congestion, “drunken appearance”. It can be accompanied by loss of appetite, nausea, vomiting, abdominal pain, diarrhea and other symptoms, and can appear hypotension, oliguria; 3, mouse bite fever: mouse bite fever spirochete is one of the pathogens of mouse bite fever. It can suddenly appear high fever, chills, redness and ulcers at the bite site, and also red lines around the wound, i.e. lymphangitis. A rash may appear on the trunk, manifesting as erythema, which may fuse into patches and form hard plaques.