In SoD1 we had The Black Fever. We all know it and we all know how dangerous it could be for our band of survivors. Now in SoD2 we have The Blood Plague, this still appears very dangerous and very fatal if we don't have the syringe to cure or suppress it (unconfirmed what the syringe actually does) Theory: What if The Blood Plague was actually in SoD1? What if what we knew as The Black Fever was actually the same illness prior to finding a vaccine? What if it was named The Blood Plague after the vaccine was created when scientists understood how it affected its victims? (in the blood) It's interesting to imagine/theorize that maybe there were Blood Plague Zombies running around in SoD1 the whole time and maybe they were spreading The Blood Plague (Black Fever). There is the argument... "but blood plague zombies have red eyes" But the same could be said about Ferals. Ferals didn't have any eyes in SoD1, and now in SoD2 the Ferals have blue eyes. Post your thoughts, do you think The Black Fever and The Blood Plague could be the same illness?