Several natural causes (diseases) have been suggested, including malaria and typhoid fever. A 1998 article in the "New England Journal of Medicine" attributed his death to typhoid fever complicated by bowel perforation and ascending paralysis. Another recent analysis suggested pyogenic (infectious) spondylitis or meningitis. Other illnesses fit the symptoms, including acute pancreatitis and West Nile virus. Natural-cause theories also tend to emphasize that Alexander's health may have been in general decline after years of heavy drinking and severe wounds. The anguish that Alexander felt after Hephaestion's death may also have contributed to his declining health.