Demon fever

From NWNWiki

Initial save DC: 18
Subsequent save DC: 18
Initial ability damage: 1d6 constitution
Secondary ability damage: none
Incubation period: 1 hour
Type: supernatural effect

Demon fever is resisted upon contraction if the target makes a successful initial fortitude saving throw. After the incubation period, subsequent fortitude saves are attempted to resist the ability damage. Two successful subsequent saves in a row will remove the disease (but not the side-effects). After 24 hours, a fortitude save at DC 18 is attempted to avoid permanently losing one point of constitution.