sir, 2 years ago my brother was suffereed from urine infection and kidney infection after operation all the infection is removed and then he is good in health .doctor say that all the checkups and test are done in 6 months .we do so .but from some time after two years of operation my brother is suffering from fever from 1 month.there is no positive result in M.C.U. test,maleria ,dengu, typhoid ,...doctors saying that his fever is due to body weakness . please suggest.