NFS plague

The NFS plague, or Neurotransmitter Failure Syndrome, was a particularly virulent infection that had engulfed the Border Worlds in the 62nd century.

The onset of the disease was fairly quick, usually gestating within 2-3 days. Victims would initially experience dizziness and fatigue as their nervous system lost its electrical coherence. Middle stages of the disease were marked by a loud, constant buzzing in the ears, along with severe difficulty speaking. In advanced stages, the disease would migrate from the nervous system to the other tissues of the body, making them lose lose coherence. Sufferers were described as "having their bodies physically fall apart". (BFDE: The Healers)

Treatment for the plague was a difficult thing. While cryogenic suspension could halt the progress of the disease, it was not a long-term solution. A heavy regimen of antibiotics and chemotherapy could stabilise the victim until they were no longer contagious, but could not cure the disease or its effects.

The Daleks had developed a cure for the NFS Plague; a substance called "Variant 7." The drug was a success, freeing the plague victims of years of suffering. However, it was only administered in complex "healing zones" on geo-formed worlds. (BFDE: The Demons)

It was revealed later that the plague itself was engineered by the Daleks as a form of biological and psychological warfare. The plague would weaken the galaxy and the authorities would be desperate for help, no matter who or where it came from. The Daleks would then provide that help, covertly using the plague as a means to mutate humans into more daleks. (BFDE: The Warriors, The Future)