Aldarc
Legend
Your character dies of a heart attack. Thank you for playing.While I'm pretty sure I've never killed a character with disease, I do make them check now and then when they've been wading around in particularly disease-prone areas to see if someone picked up anything nasty. 1e D&D has some obscure rules for this, though I generally just wing it via a roll-under-Constitution; and if someone does get sick and they don't have access to a cure it could mean that character's laid up for a few days (and-or just less effective) which serves to delay the PCs and give their foes more time. The delay could put added pressure on their rations etc. as well in the right situation.
Once Cure Disease or similar comes online, though, disease becomes fairly irrelevant unless for some reason they're starving for spells.