Upon taking damage from enemies (but not firearms or explosive traps) or being near infectious gas, the character's infection gauge will slowly increase. Once it is passes certain thresholds a player will then become that level of infection ranging 1-3. While infected, characters will randomly pause to cough and loose a small amount of health. The higher the infection level the more frequent and higher the damage taken. Blue Herbs and Infection Treatment Spray will remove Infection status.