If the white blood cells are normal or low, and the neutrophils are high, it can be basically determined that the fever is caused by a viral infection. The fever caused by viral infection has its own characteristics, usually high fever, persistently does not drop, after the fever subsides, the spirit as usual, there is no special drugs for viral infection, is a self-limiting disease, generally fever ranging from 3-10 days, within 1 to 2 weeks of self-healing. From the incidence of fever, 85% to 90% is due to viral infection, bacteria is probably less than 10%, about the fever caused by viral infection, and bacterial infection is not the same, the general cold rarely high fever, generally low fever 1 to 2 days to reduce fever, but the systemic reaction is more serious, the fever caused by viruses for high fever, fever, fever after the spirit is very good, no systemic symptoms, general fever 3 to 10 If the fever is more than two kinds and the systemic symptoms are obvious, it is possible that the viral infection is followed by bacterial infection, and the chance of using antibiotics is increased. The application of antiviral drugs can also shorten the duration of the disease, for example, ribavirin and oseltamivir phosphate can improve the fever caused by viral infections and promote the recovery of the patient. For fever caused by viral infections, no medication is usually needed, as self-limiting diseases usually have fever for 3-5 days, very few patients with poor health may have fever for a longer period of time, but not more than two weeks, if more than that, secondary bacterial infections should be considered. It is recommended to pay attention to the fever for more than a week and seek medical treatment in time.