Virulence
Version 0.14: This article may not be up to date for the latest stable release of Crawl.
Virulence is a monsters-only spell which increases the poison level of its victim to 150% of its current level. This has little effect when cast on a lightly poisoned character, but can lead to a massive increase in damage taken for characters already at light or dark red poison levels.
Remember that no matter how much poison you have coursing through your veins, one potion of curing will remove all of it.
The following monsters cast Virulence:
History
Virulence was added in 0.14.