Sleeping fever

Sleeping fever was a deadly disease that afflicted the Ice Warrior civilization on Mars and was an infection that specifically targeted their own biology which meant that it was not a threat to other species. Martian geneticists were known to had chosen the sleeping fever as the basis for many forms of bacteriological and biological weaponry since it burnt itself out in less than a decade. This allowed the deployment of such weapons to cleanse a settlement of its inhabitants and leave the city intact but uninhabited. It was known that whilst the Martian warrior caste had attempted to tame the disease for their own use, it was known to still occur naturally and inflict various regions of the planet.

Over five centuries before 2157, the city of Sstee-ett-Haspar suffered from an outbreak of sleeping fever with a Plague Seal left in place to warn travelers of the dangers within. (NA: GodEngine)