Whether a child’s cold and fever is a viral infection or a bacterial infection in the spring is usually determined by clinical symptoms, routine blood tests or blood cultures. 1. Viral infection: fever after viral infection is usually mild, about 3-5 days can be self-cured, in addition to fever, can be accompanied by cough, runny nose and other symptoms, of which the runny nose is mostly clear. Blood tests show that white blood cells are normal or decreasing, lymphocytes are increasing, and C-reactive protein is generally at a normal level. 2. Bacterial infection: fever after bacterial infection is generally more serious symptoms, body temperature can be increased in a short period of time, and there are symptoms such as limb pain, headache, chills, runny nose, etc., in which the runny nose is mostly pus. Blood routine examination of white blood cells, lymphocytes, C-reactive protein can be increased, blood culture can detect pathogenic bacteria. Therefore, in the spring, children with colds and fevers, whether viral or bacterial infections, should go to the hospital in a timely manner, under the guidance of the doctor for treatment.