Hi and thanks for your question, leuciocyte esterase associated with positive white blood cells is suggestive of a urinary tract infection. Chronic fever as you describe deserves a more critical look. The first things which must be excluded in this clinical picture of back ache, chronic fever and pus cells in urine is extralmonary tuberculosis, especially urinary tract TB or spinal TB (potts disease). A chest X ray, spinal x rays and an Intradermal reaction to exclude these conditions are very vital. An HIV serology, clinical screening for sarcoidoisis, a tumour, chronic inflammatory autoimmune diseases are worth being excluded. I suggest you get an apintment with an internist for a proper clinical evaluation and orientation towards the source of these symptoms. Thanks and best regards, Luchuo, MD.