Lazar's disease

Lazar's Disease was a contagious and eventually fatal disease. These victims are referred to as Lazars. It can be transported by air, but touch is a much more effective carrier. When infected, the victim becomes exhausted and confused. Eventually, they take on a pale and haggard appearance and become even more weakened. This disease can drag on, with the Lazar becoming even weaker and more sickly, until they eventually die.

Though the Doctor, Nyssa, Kari and Olvir all were in a similar situation while on Terminus, only Nyssa was infected. This may be due to a natural immunity or just luck.

Lazar's disease can be staved off with repeated doses of hydromel or cured with controlled doses of radiation. The later remedy, for obvious reasons, entailed more risk to the infected person. (DW: Terminus)