- "Plague, Dramia II. Of unknown origin characterized by pigmentation changes in skin of victim, debilitation, death. Certain species known to have natural immunity, notably Vulcan."
Individuals affected with the plague experienced a change in pigmentation from blue, to green, to red. It was later determined that the cause for this color change was due to aurora borealis interference.
The Dramians blamed McCoy for the plague and, in 2270, arrested McCoy and placed him on trial for mass murder. The USS Enterprise visited Dramia II to clear McCoy's name, but became stricken with the plague themselves. Upon the return to Dramia, Spock conducted a jailbreak, and released Dr. McCoy so that he could determine a cure for the plague.
It was soon after determined that the aurora played a part in the plague, however, no known antidote could be determined. After further investigation, it was determined that Saurian virus antibodies in the bloodstream of one of the original plague survivors created an immunity to the plague. (TAS: "Albatross")