SRD:Disease

Disease
When a character is injured by a contaminated attack, touches an item smeared with diseased matter, or consumes disease-tainted food or drink, he must make an immediate Fortitude saving throw. If he succeeds, the disease has no effect — his immune system fought off the infection. If he fails, he takes damage after an incubation period. Once per day afterward, he must make a successful Fortitude saving throw to avoid repeated damage. Two successful saving throws in a row indicate that he has fought off the disease and recovers, taking no more damage.

These Fortitude saving throws can be rolled secretly so that the player doesn’t know whether the disease has taken hold.

Disease Descriptions
Diseases have various symptoms and are spread through a number of vectors. The characteristics of several typical diseases are summarized on Table: Diseases and defined below.

Disease
Diseases whose names are printed in italic in the table are supernatural in nature. The others are extraordinary.

Infection
The disease’s method of delivery—ingested, inhaled, via injury, or contact. Keep in mind that some injury diseases may be transmitted by as small an injury as a flea bite and that most inhaled diseases can also be ingested (and vice versa).

DC
The Difficulty Class for the Fortitude saving throws to prevent infection (if the character has been infected), to prevent each instance of repeated damage, and to recover from the disease.

Incubation Period
The time before damage begins.

Damage
The ability damage the character takes after incubation and each day afterward.

Types of Diseases
Typical diseases include the following:

Blinding Sickness
Spread in tainted water.

Cackle Fever
Symptoms include high fever, disorientation, and frequent bouts of hideous laughter. Also known as “the shrieks.”

Cascade Flu
Spread by brain moles and other vermin. A psionic cascade is a loss of control over psionic abilities. Using power points becomes dangerous for a character infected by cascade flu, once the incubation period has run its course. Every time an afflicted character manifests a power, she must make a DC 16 Concentration check. On a failed check, a psionic cascade is triggered. The power operates normally, but during the following round, without the character’s volition, two additional powers she knows manifest randomly, and their power cost is deducted from the character’s reserve. During the next round, three additional powers manifest, and so on, until all the psionic character’s power points are drained. Powers with a range of personal or touch always affect the diseased character. For other powers that affect targets, roll d%: On a 01–50 result, the power affects the diseased character, and 51–00 indicates that the power targets other creatures in the vicinity. Psionic creatures (those that manifest their powers without paying points) cascade until all the powers they know have manifested at least twice.

Cerebral Parasites
Spread by contact with infected psionic creatures. Cerebral parasites are tiny organisms, undetectable to normal sight. An afflicted character may not even know he carries the parasites—until he discovers he has fewer power points for the day than expected. Psionic creatures with cerebral parasites are limited to using each of their known powers only once per day (instead of freely manifesting them).

Demon Fever
Night hags spread it. Can cause permanent ability drain.

Devil Chills
Barbazu and pit fiends spread it. It takes three, not two, successful saves in a row to recover from devil chills.

Filth Fever
Dire rats and otyughs spread it. Those injured while in filthy surroundings might also catch it.

Mindfire
Feels like your brain is burning. Causes stupor.

Mummy Rot
Spread by mummies. Successful saving throws do not allow the character to recover (though they do prevent damage normally).

Red Ache
Skin turns red, bloated, and warm to the touch.

The Shakes
Causes involuntary twitches, tremors, and fits.

Slimy Doom
Victim turns into infectious goo from the inside out. Can cause permanent ability drain.

Healing a Disease
Use of the Heal skill can help a diseased character. Every time a diseased character makes a saving throw against disease effects, the healer makes a check. The diseased character can use the healer’s result in place of his saving throw if the Heal check result is higher. The diseased character must be in the healer’s care and must have spent the previous 8 hours resting.

Characters recover points lost to ability score damage at a rate of 1 per day per ability damaged, and this rule applies even while a disease is in progress. That means that a character with a minor disease might be able to withstand it without accumulating any damage.