The black death, still kills 2,000 people a year.
(It's caused by the bacterium Yersinia pestis, a plague that is primarily a disease of wild rodents and is spread by their fleas. It is one of the "oldest identifiable diseases known to man", according to the World Health Organization (WHO), and believe it or not, it has never been wiped out. Luckily nowadays, almost all cases are curable if diagnosed in time.)