Recurrent fever caused by bacterial and viral infections is the result of untimely treatment or incomplete treatment and failure to use sensitive antibiotics. Since bacterial and viral infections are dual pathogen infections, the treatment time is relatively long. Bacteria and viruses are pathogens, and when they infect the body, excessive bacteria or viruses in the blood can lead to fever, and blood tests usually show an increase in white blood cells, neutrophils and lymphocytes. When the body’s resistance is reduced or poor immune function, bacteria and viruses can easily invade the body to produce symptoms, such as fever, fever can be seen in many kinds of diseases, body temperature is one of the four vital signs, body temperature is higher than normal, indicating that a part of the body disease, it is necessary to give timely and detailed examination to find out the cause of the disease and timely treatment.