Disease

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:Main article: Disease
Diseases are temporary and treatable ailments, that pass away after a certain amount of time or treatment.
== Contract ==
Most diseases are contracted as part of an event. Your colony's biome determines how common diseases are, as well as how common each disease is. However, some diseases happen situationally, regardless of biome:
*Infection may occur after a bleeding injury, burn, or frostbite is inflicted. Tending the injury in a clean room reduces the chance of infection.
*Lung rot occurs randomly when inhaling enough rot stink.
*Blood rot and paralytic abasia are exclusively part of quests, while infant illness can only happen during birth.
Note that diseases are not contagious in RimWorld. Disease does not ever spread between colonists, though disease events often simulate "outbreaks" by inflicting multiple colonists at the same time.
The drug penoxycyline protects against Malaria, Plague, and Sleeping sickness. The disease event still happens, but colonists will not be affected.
== Summary ==
Humans and animals can get diseases. Most diseases uses the severity mechanic. As a disease progresses, its symptoms progressively get worse. If a fatal disease's severity reaches 1.0 (100%), then death occurs. Most diseases go from minor -> major -> extreme. How fast a disease progresses depends on the disease itself.
== Diseases ==
Note: Base values of severity and immunity gain speed used in the table.Treatment's reduction of severity depends on tend quality. 50% tend quality equals half the reduction.
Disease 	Fatal?	Description	Severity	Treatment
Infection 	 	Generic infection of individual wounds. 
*Fast moving and dangerous. 
** < 1.25 days to kill if untreated. <1.5 days for immunity.
*Mild symptoms until extreme severity (>0.87). ( to pain)	
* Severity: +0.84 / day
* Immunity: +0.644 / day
* Treatment: -0.53 severity / day (at 100% quality)	
* Bed rest and medicine
* Amputation of infected body part
Flu 	 	Relatively mild and common disease.
*Non-elderly adults can survive without treatment, with just bedrest.
*Lowers consciousness, manipulation, breathing ( to ).	
* Severity: +0.249 / day
* Immunity: +0.239 / day
* Treatment: -0.077 severity / day (at 100% quality)	
* Bed rest and medicine
Malaria 	 	Common in tropical biomes.
* Attacks blood filtration, slowing immunity speed.
* Later stages cause pain and reduces consciousness.	
* Severity: +0.370 / day
* Immunity: +0.314 / day
* Treatment: -0.232 severity / day(at 100% quality)	
* Bed rest and medicine
Plague 	 	Fast moving and extremely painful.
* ~1.5 days to kill if untreated.
*Constant pain ( to ).
*Also reduces consciousness and manipulation (up to ).	
* Severity: +0.666 / day
* Immunity: +0.522 / day
* Treatment: -0.362 severity / day (at 100% quality)	
* Bed rest and medicine
Sleeping sickness 	 	Very slow-moving infection. Native only to rainforests and swamps.
*Relatively easy to treat if rested. 
* Threat is the amount of rest / medicine required.
*Mainly lowers consciousness & manipulation ( to ).	
* Severity: +0.12 / day
* Immunity: +0.11 / day
* Treatment: -0.07 severity / day (at 100% quality)	
* Bed rest and medicine
Scaria 	 	Drives animals to become manhunters. 
*Exclusive to animals in manhunter packs. 
*Humans and colony animals immune.	
* Kills in 5 days, unless cured	
* Surgery
** 3 medicine
**Medical Skill 8+
Lung rot 	 	
Occurs after enough exposure to rot stink. Avoid rot stink to avoid.
* Resisted by sources of Toxic Environment Resistance.
* Easily treatable overall. Can drain medicine.
* Impairs breathing slightly. Minimal symptoms overall.	
* Severity: +0.300 / day
* Treatment: -1.000 severity / day (at 100% quality)	
* Medicine
Resolves from:
*Min 
*Max
Gut worms 	 	Doubles hunger rate.
*Also painful ( pain).	
* No progression
* Cured at 300% total Tend Quality	
* Medicine (48hr per tend)
* Stomach replacement or removal
Muscle parasites 	 	Heavily impairs work.
*Significant tiredness.
*Lowered manipulation and movement speed ().
*Also painful ( pain).	
* No progression
* Cured at 300% total Tend Quality	
* Medicine (48hr per tend)
Fibrous mechanites	 	Very long-lasting, but improves working.
*Painful, significant tiredness.
*Significantly increases manipulation, moving and blood pumping ( to all).	
* Severity: +0.25 / day
* Treatment: -1.00 severity / day (at 100% quality)	
* Medicine
**Prevents pain increase only
Resolves from:
*Min 
*Max
Sensory mechanites	 	Very long-lasting, but improves many stats.
*Painful, significant tiredness.
*Significantly increases sight, hearing, and talking ( to all).
*Increases manipulation ().	
* Severity: +0.25 / day
* Treatment: -1.00 severity / day (at 100% quality)	
* Medicine
**Prevents pain increase only
Resolves from:
*Min 
*Max
Organ decay 	 	No natural cure. Only targets specific organs.
*Causes increasingly worse pain and weakened part efficiency of the afflicted organ, ultimately destroying it at 1 severity.
*Only treatable by replacing the organ.
*Only targets the heart, lungs and kidneys.
*Can appear rarely as a disease event, or on Creepjoiners.	
* Severity: +0.0166 to 0.0334 / day	
* Replacing the organ
**Does not affect bionic or prosthetic organs
Reaches max severity after:
*Min 
*Max
Blood rot 	 	Extremely long lasting blood affliction.
*Quest only.
*Mild and easily treated, but can be a drain on medicine.	
* Severity: +0.40 / day
* Treatment: -1.00 severity / day (at 100% quality)	
* Medicine
* Surgery for immediate cure
** 10 glitterworld medicine
**Medical Skill 5+
Resolves from:
* Min 
* Max
Paralytic abasia 	 	Complete immobility. Extremely long lasting.
*Quest or transport pod crash only.	
* No progression
* 1% per day to instantly cure	
* Waiting
* Surgery for immediate cure
** 10 glitterworld medicine
**Medical Skill 5+
Always resolves after:
* Min 
* Max
Infant illness 	 	Inflicted after a sick birth of a baby.
*4 different types of illness, from mild to grave. Switches every 1-3 days.
*Uniquely, reducing severity to 0 cures the disease (no immunity required).	
* Starts as Major severity (0.40)
* Severity gain depends on the type
** From -0.25 to +0.5 severity / day
* Immunity: +0.10 / day
* Treatment: -0.35 severity / day (at 100% quality)	
* Medicine and bed rest
== Treatment ==
Most diseases can be tended to, just like an injury or ailment, by a Doctor pawn and when the afflicted pawn is assigned to Patient themselves. Tend Quality is determined by a variety of factors, including the doctor's skill and the quality of Medicine used. Generally, higher quality tends reduce the total time until recovery, though mechanics vary. How often a disease can be tended depends on the disease itself.
There are 3 types of diseases to tend to:
* The disease will progress over time, and treatment slows down progression. Immunity is gained over time, dependent on Immunity Gain Speed and independent of tend quality. Once immune, the disease will slowly fade and the colonist will stop being a patient. This applies to most fatal diseases, including the flu, infection, and plague.
* The disease does not progress. Treatment must reach a total tend quality (300%) before the disease is cured. For example, 4 tends at 80% quality would equal 320% total tend quality. Applies to gut worms and muscle parasites.
* The disease progresses over time, and treatment slows and even prevents progression. The disease fades only after a certain time. Applies to lung rot, fibrous mechanites, sensory mechanites, and blood rot.
Certain diseases have specialized cures. For example, infection in a non-vital part can be cured by amputating or replacing a limb, blood rot can be instantly cured with glitterworld medicine, and gut worms can be treated by replacing the stomach. In addition, a healer mech serum immediately cures any disease.
=== Immunity gain ===
Some diseases are a race between the increasing severity of the disease and the increasing immunity to it. This immunity gain is controlled by several factors:
* Base immunity gain speed for the particular disease. 
* InfectionLuck, an uncontrollable generated value that adds randomness to the diseases progression. Each disease has a variance in Immunity gain speed of 20% up or down. 
* The Immunity Gain Speed stat of the patient
Immunity Gain Speed is affected by the following:
* Food: Pawns above 12.5% Saturation do not have any penalties to immunity.
* Rest: Actively resting gives a bonus to speed. Resting in any bedroll or bed increases the stat, a hospital bed increases it further, and a hospital bed with an attached vitals monitor increases it the most.
* Age: As a pawn gets closer to and past their species' life expectancy, immunity gain speed decreases. 
** For baseline humans, immunity gain speed is gradually lost after age 54. Genes like cell instability can affect the pawns lifespan and, in turn, affect this progression.
* Blood Filtration: Mostly increased via luciferium. Reduced with kidney or liver damage, slightly improved with a detoxifier kidney.
* Direct boosts: The Super-immune trait, Immunoenhancer, and genes can increase immunity speed.
Note that these only apply to diseases with immunity mechanics. For example, you don't need to give a pawn with gut worms bedrest.
== Disease frequency ==
=== Disease frequency by AI storyteller ===
Disease frequency is controlled directly by the Disease frequency AI storyteller setting. 
This value can be changed in custom storyteller settings, but has the following default values by difficulty:
Difficulty 	Disease interval multiplier
Peaceful 	3
Community builder	2.5
Adventure story 	1.3
Strive to survive	1.0
Blood and dust 	0.95
Losing is fun 	0.9
=== Disease frequency by biomes ===
== Version history ==
* 0.7.581 - Added with flu, plague, malaria, sleeping sickness.
* 0.9.722 - Diseases can now cause vomiting.
#Disease