Gearbox has given official words about the virus called "Graveyard" which is affection PC and Xbox 360 players, as they have stated that PS3 players are unaffected by this threat.
The
Graveyard Virus is an infection which is being spread through duplicated and shared items, which -when someone acquires them- will silently change the game's difficulty from any to Hardcore, which is the only one featuring a "one life only" for players' characters.
The name of this infection has been given due to its purpose, which basically is that when a player's character dies, it won't come back.
Gearbox's recommendation is to only play only in private online matches with people that you know, and that for sure isn't infected; as well, they are suggesting that, if you got infected and you failed to get a Second Wind during "Fight for your Life" to immediately press on
"Continue", and to always end the game session by pausing the game and selecting the
Save and Quit option.
A fix for this infection is being worked on by Gearbox's developers, and they announce that this situation will be solved soon, yet without providing an exact date for it.