What did William Byrd II die from?

According to a study, published in February 2007, by Antonio Rodriguez Cuartero, Department of Internal Medicine of the University of Granada, he died of a heart attack caused by Reiter's Syndrome (also called reactive arthritis). According to his personal diaries and notes by contemporaries, the symptoms of this illness (burning pain during urination, pain and swelling of the knees, and conjunctivitis of the eyes) were clearly visible in his last three years.