Reuters reports that dental evidence indicates the plague that struck Athens during the second year of the Peloponnesian War may have been Typhoid Fever. The evidence comes from DNA in teeth found in an ancient mass burial pit. Besides Typhoid Fever, earlier candidates for the plague that may have killed as many as one third of the Athenians had been smallpox, bubonic plague, anthrax, and measles.

Thucydides wrote about the plague that killed the Athenian leader Pericles in his history of the Peloponnesian War. Here is the relevant section.

Read the Reuters article: Typhoid fever linked to ancient plague of Athens or Kathimerini's article: Secret of ancient Athens plague is being unraveled Greek scientists find typhoid after excavating graves or on the Discovery Channel's site: Typhoid Contributed to Athens' Downfall.

In A.J. Bollett's Plagues and Poxes, Typhus and Typhoid are excluded from the look at historical epidemics because it is too hard to determine from documents which disease is being described. (Both are named after the Greek monster Typhon.) The Reuters article specifies the DNA as being similar to modern day Salmonella enterica serovar Typhi.

For more information on the research, see Kris Hirst's Was the Plague of Athens Typhoid?