Back in the present, the original Lister is shown coming to the realisation that the parallel Lister had to have died in the radiation leak that wiped out Red Dwarf, and the parallel Lister explains that he was brought back as a hologram by that universe's version of Holly.
In "Epideme" (1997), Lister is infected by the Epideme virus (voiced by Gary Martin) after it transfers from the corpse of one of Red Dwarfs old crewmembers, Caroline Carmen (Nicky Leatherbarrow), into Lister's body.