The Viral Strain of the processing bile is simply a different form. Based on the ooze
genetic template it remains a living organism, but it's spread like a disease through living creatures.
Living creatures who contract this viral strain become sick within a week and within two days are quickly bedridden. Depending on the situation it could then take three weeks to a few days for the viral strain to fully infest the living creature, creating an infested version of the creature.
In the beginning stages it manifests as a mild cough, but within two days it worsens until the victim is bedridden. During the bedridden stage the victim begins coughing up black bile as the viral strain begins to feed and reproduce inside the victims body. As it progresses the victim proceeds to the vomiting stage where they start regurgitating larger amounts of the black bile.
By the five day mark the victims will begin to exhibit black stains on their skin in splatter patterns wherever they cough or vomit on themselves. From there they begin to manifest spines and tendrils that grow and grow until...
Because it is specifically a living organism it's better classified as a parasite rather than a disease or poison. Regular healing magic can temporarily slow the infection process as it repairs the damage done to the creature, but healing magic will also heal the strain in the process, allowing it to propagate and redouble its infestation efforts to an even greater degree.
Healing potions, herbs, medicines and other normal or magical methods of curing diseases are treated as food to help the strain grow and quicken the process of infestation. But dark magics, negative healing and necrotic energy can kill off the disease.