Kharaa Bacterium

The Virus is an affliction that seems to be all over Planet 4546B. It is described in the Degasi PDAs as "part of the ecosystem". It is suggested that the Degasi survivors were infected at some point, as stated by Bart Torgal.

Afflicted creatures will be identifiable by the small, glowing cysts on their body.

Warpers will attempt to kill infected creatures once their infection passes a certain level.

The player is infected with the Virus, though it only becomes noticeable at a certain point in the story.

If an infected creature is placed inside an Aquarium or Alien Containment, the creature will infect the rest of the creatures inside soon after. But this has no gameplay effect.

Trivia

 * The Virus is loosely based off the appearances of the Kharaa from Natural Selection 2, as the Kharaa had similar looking cysts on their body.