Neonism / Vampirism
Transmission & Vectors
The artificially created virus causing this condition stays in a host indefinitely. The infection does not spread over-the-air, but does so via body fluids, which makes the bite of an infected individual infectuous.
Causes
Neonism was initially inflicted by the Experimental Serum Omicron, a liquid containing a genome-altering virus constructed by Brightlight Research.
Symptoms
The first effect is the change of an infected human's blood into a different, radiant colour. At around the same time, the infected's cells stop aging and the healing of wounds accelerates. Shortly after that, the heart of the individual stops beating without them dying. The last of the symptoms is a quickly increasing appetite for human blood.
Prevention
Yeah it's pretty fucking simple honestly. Don't let the fuckers bite you.
History
Neonism is part of the effect of Experimental Serum Omicron, a treatment for mortality, as its inventors probably called it. It was first injected into lead researcher Dr. Brightlight, thereby making him Patient Zero.
The serum was injected in several wealthy clients who did not wish to die and paid insane sums to acquire a remedy for death. Although these were provided with blood bags to sate their hunger, it was only a matter of time until they bit and infected other people. After few of these cases, people lost track of the patients and neonism became an epidemic.
I imagine most doctors in their professional lives, in most settings, will find THAT sort of patient from time to time. The one who "did not wish to die". Awkward people they must be, those patients. Probably.