my son is suffering from low grade fever since a month(99-100) all the tests concerned are negative blood culture , montux , widal , torch ,calcium serum ,urine ,stool,x-ray chest,ultrasound abdomen ,x-ray pns, ct chest and head(normal and contrast) he has no other symptoms on the 5th day of fever the ESR was 43 which has increased to 76 on the 15th day of fever .plus on the tenth day of fever he got iritis in his left eye which has resolved but has occured in the right eye since two days. he was given a course of lariago and antibiotics for 12 days(azithral 500mg BD and Taxim-o 500mg OD)