Fever without any symptoms. What's going on?

Fever is mostly caused by infection, common in viruses, bacteria and other pathogens, viruses and bacteria and other pathogens widely exist in life. If the patient's immune function declines, it is easy to be infected. It is recommended to rest more during the fever period, increase the amount of water to help promote the body metabolism, fever temperature more than 38.5 degrees, can take antipyretic cooling.