Here are a list of links related to diseases.

A glossary of archaic medical terms, diseases and causes of death -
http://www.antiquusmorbus.com/

Disease chart A to Z -
http://www.cdc.gov/DiseasesConditions/

List of epidemics [outbreaks affecting large groups of peoples] from Wikipedia -
http://en.wikipedia.org/wiki/Epidemics

Links to information about the histories of diseases, presented by the Karolinska Institutet -
http://ki.se/ki/jsp/polopoly.jsp?l=en&d=1388&a=4145

Yellow Fever - Timeline
PBS presents a timeline of Yellow Fever in America, from 1495 to 1503 -
http://www.pbs.org/wgbh/amex/fever/

You may also find this site interesting:
https://familyhistory.hhs.gov/fhh-web/home.action