THE CURSE is the means by which human beings are permanently transformed into creatures. To date there is no known cure.
The most commonly accepted theory is that THE CURSE is spread via bodily fluids. This can entail such things as bites that draw blood, unprotected sex, or even contact with creature saliva on the rim of a glass. Rape is a very common means of transmission.
THE CURSE is believed to be hereditary. Even seemingly human children or grandchildren of creatures have been known to spontaneously transform despite no previous infections.
Consumption of Faygo can create a resistance, and in heavy doses, immunity to THE CURSE. THE CURSE also seems to be denatured in the open air rather quickly. It is theorized that creatures are unable to spread THE CURSE when disguised as humans. No one has been willing to test this.