Hi, Welcome to HCM! There can be several reasons which cause fever (warm temperature). However, there is nothing to worry about immediately. Your father might be suffering from Viral infection, which is the commonest reason for fever with headache and joint aches. Hepatits is another cause which might result in fever. Since the report is negative, it rules out the possibility of Hepatitis C. So, most probably, what your father is having is simple viral fever. Viral fevers are self limiting fevers, which take about 7-8 days before healing by themselves. We give treatment only according to symptoms. If I were your treating doctor, I d give your dad 1. A paracetamol, to reduce the fever. This can be taken 3-4 times a day. 2. Paracetamol will not only reduce fever, but also reduce headache. If he still has headache, he might be given a more powerful painkiller, namely diclofenac. 3. In case his fever is very high, (above 39 degrees), do cold tepid sponging. For this, wet a cloth and apply it to his whole body. This will immediately reduce fever. This treatment is enough. If he doesn t get a better even after a week, visit your doctor. Also, as a precaution, get a malaria and dengue test done, if you reside in an endemic area. Hope this information helps. Feel free to ask if you have any doubt. Wishing your father a speedy recovery. With warm regards, Dr. Sridhar