Here is the full list of all 8 Outbreak: Epidemic achievements.
Achieve Level 2 as the Survivor class.
Achieve Level 2 as the Leader class.
Achieve Level 2 as the Reporter class.
Achieve Level 2 as the Medic class.
Achieve Level 2 as the Renegade class.
Achieve Level 2 as the Lumberjack class.
Achieve Level 2 as the Marksman class.
Achieve Level 2 as the Adventurer class.