Recurrent Fever

A 45 year old man presents with low grade intermittent fever of 4 weeks duration which is associated with night sweats, loss of appetite and weight loss. He also suffers from a mild productive cough, mostly during the daytime. He denies exposure to gases, fumes or toxic chemicals and is not on any drugs. He comes from a low socioeconomic background. He denies unsafe sexual encounters and has no history of blood transfusions.