The Black Plague killed an estimated 50 million Europeans between 1347 and 1351. In a research paper released Wednesday, researchers from Germany, Canada, the United States and Colombia sequenced the genome of Yersinia pestis, the bacterium that caused the plague that killed a third to half of the European population nearly 700 years ago.

Fast forward several centuries, and the Black Plague is no longer a menace to the world. However, infectious diseases still kill millions of people annually worldwide, though not at the scale of the Black Plague. Below is a list of the top five infectious disease killers, according to 2004 data in a report issued by the World Health Organization in 2008. Infectious diseases are only listed; the world's top killer was heart disease that killed 7.2 million people.

  1. Lower respiratory  infections killed 4.2 million people in 2004
  2. Diarrhoeal diseases killed 2.2 million people
  3. HIV/ AIDS killed 2 million people
  4. Tuberculosis killed 1.5 million people
  5. Neonatal infections killed 1.1 million infants

Source: Global Burden of Disease: 2004 update