There are many causes of prolonged hypothermia, commonly due to viral colds, mycoplasma infections, tuberculosis, functional fever, and vegetative disorders. Patients can usually be seen at the Infection Unit of the hospital for routine blood, urine, stool, liver and kidney functions, and ultrasensitive C-reactive protein. Depending on the situation, tests such as rheumatoid factor, blood sedimentation, thyroid function, anti-streptococcal haemolysin O test, chest X-ray, and tuberculin test can be added, and symptomatic treatment can be administered according to the results of the tests.