From a widespread plague to the bite of a dire rat, disease is a serious threat to common folk and adventurers alike. Diseases rarely have a limited frequency, but most have a lengthy onset time. This onset time can also be variable. Most diseases can be cured by a number of consecutive saving throws or by spells such as remove disease.
The following samples represent just some of the possibilities when creating diseases.
Blinding Sickness
Type disease, ingested; SaveFortitude DC 16
Onset 1d3 days; Frequency 1/day
Effect 1d4 Str damage, if more than 2 Str damage, target must make an additional Fort save or be permanently blinded; Cure 2 consecutive saves
Bubonic Plague
Type disease, injury or inhaled; SaveFortitude DC 17
Onset 1 day; Frequency 1/day
Effect 1d4 Con damage and 1 Cha damage and target is fatigued; Cure 2 consecutive saves
Cackle Fever
Type disease, inhaled; SaveFortitude DC 16
Onset 1 day; Frequency 1/day
Effect 1d6 Wis damage; Cure 2 consecutive saves
Demon Fever
Type disease, injury; SaveFortitude DC 18
Onset 1 day; Frequency 1/day
Effect 1d6 Con damage, target must make a second Fort save or 1 point of the damage is drain instead; Cure 2 consecutive saves
Devil Chills
Type disease, injury; SaveFortitude DC 14
Onset 1d4 days; Frequency 1/day
Effect 1d4 Str damage; Cure 3 consecutive saves
Filth Fever
Type disease, injury; SaveFortitude DC 12
Onset 1d3 days; Frequency 1/day
Effect 1d3 Dex damage and 1d3 Con damage; Cure 2 consecutive saves
Leprosy
Type disease, contact, inhaled, or injury; SaveFortitude DC 12 negates, Fortitude DC 20 to avoid effects
Onset 2d4 weeks; Frequency 1/week
Effect 1d2 Cha damage; Cure 2 consecutive saves
Mindfire
Type disease, inhaled; SaveFortitude DC 12
Onset 1 day; Frequency 1/day
Effect 1d4 Int damage; Cure 2 consecutive saves
Red Ache
Type disease, injury; SaveFortitude DC 15
Onset 1d3 days; Frequency 1/day
Effect 1d6 Str damage; Cure 2 consecutive saves
Shakes
Type disease, contact; SaveFortitude DC 13
Onset 1 day; Frequency 1/day
Effect 1d8 Dex damage; Cure 2 consecutive saves
Slimy Doom
Type disease, contact; SaveFortitude DC 14
Onset 1 day; Frequency 1/day
Effect 1d4 Con damage, target must make a second Fort save or 1 point of the damage is drain instead; Cure 2 consecutive saves