|Location||Unholy Tree, Tier 2|
|Affects||Blood Plague and Frost Fever|
Epidemic is a Death knight talent located in the 2nd tier of the Unholy Tree. It increases the duration of Blood Plague (caused by Plague Strike) and Frost Fever (caused mainly by Icy Touch) from 15 to 21 seconds. The damage dealt per second of the diseases is unchanged, so the talent causes the diseases to deal more total damage over their full durations.
The main value of the talent is that two points increases the durations beyond the 20 second mark, meaning that they only need to be refreshed every other time your runes come off cooldown. Because of this, two points in this talent are included in virtually every death knight talent build.
Tips and tactics
Two points in Epidemic are required to make full use of the Glyph of Disease, as you are otherwise forced to refresh the diseases after just 10 seconds; a full 5 seconds before they expire. With the talent you can use Pestilence every 20 seconds rather than every 10 seconds. This is important as your runes have a 10 second refresh time and should be used as soon as they are available.
/ Patch 4.0.1 (12-Oct-2010): Now increases disease duration by 4/8/12 sec, up from 3/6 sec.