Valve revealed the first playable campaign for Left 4 Dead 2 at E3 2009, which was called “The Parish”. Today they announced that the second campaign, titled “Swamp Fever” will be playable at Comic Con 2009 next week.

Whereas The Parish takes place in a ruined New Orleans, Swamp Fever looks to take place in… well, you figure it out.

A teaser screenshot:

No, it's not the Citadel in the background

From the press release:

The game will be playable in the EA Gaming Lounge Presented by Xbox 360 from 2-9 pm Thursday-Saturday, and 12-5 pm on Sunday. The EA Gaming Lounge will be located in the Hilton San Diego Gaslamp Quarter Hotel, 401 K. Street.