A low-grade fever at night without fever during the day is not necessarily due to AIDS, but may also be related to viral infections, tuberculosis and other diseases. AIDS can have symptoms of fever, but the presence of fever symptoms is not necessarily caused by AIDS. In the acute stage of AIDS, there may be symptoms of fever, which are mild and can be relieved on their own, but there is no specific manifestation of no fever during the day and low fever at night. No fever during the day and low fever at night may also be related to viral infection, but the viral fever temperature is generally higher and lasts longer. The systemic symptoms caused by it are more obvious, such as body aches and pains, headache and so on. It may also be accompanied by functional changes in other body organs. The most notable feature of tuberculosis is a low-grade fever in the afternoon, often accompanied by fatigue. This is characterized by an increase in body temperature in the afternoon or evening, which drops to normal the next morning, also known as hot flashes. Fever symptoms caused by TB are mainly related to the stage of disease progression, the severity of the disease, and the presence of comorbidities. If the fever symptoms do not subside, the patient should seek medical treatment without delay.