Infection

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Overview

Infections can occur on insufficiently treated or untreated wounds, burns, and frostbite (but not missing body parts). Infections are the fastest working illness in RimWorld, taking little more than a day to kill the victim if left untended. Animals can also contract infections.

General symptoms include a small amount of pain and partial loss of part function. Advanced symptoms include a small-moderate amount of pain, slight loss of consciousness and further loss of part efficiency, and shortly after: a loss of consciousness, an excruciating amount of pain, and acute part failure, along with a slight loss of breathing. Death follows not long after.

Infections are also unique in that they are visible immediately when contracted. With the majority of the other diseases, there is a slight delay before symptoms kick in. Therefore it's important infected are bedded and treated as soon as possible.

If left untreated, infections can kill in 1.163 days from contraction.
Good treatment will slow the disease to the point where it takes 3 days to kill.

It takes around 1.466 days to develop immunity to an infection, assuming the affected colonist is rested in an ordinary bed for the whole time, has normal blood filtration, is well-fed, and under the age of 40.

Unlike most diseases, this disease only affects a specific body part, making infections curable by amputating the affected body part. It is not possible to amputate an infected head or torso.

In Alpha 17 the frequency of infections occurring has been increased, and can occur even if the wound is treated (though less frequently). It also causes a loss in part efficiency, and because of this, if it causes the efficiency of a vital part to reach 0%, the pawn will die instantly.

Colonist died before infection reaches 100% due to 0% torso efficiency.

Mechanism

When a colonist has an infectable wound the game will count down randomly from 15,000 ticks (250 secs) to 45,000 ticks (750 secs). Once it reaches this timer it will decide if the wound will be infected.

The chance of a pawn getting an infection depends on the tend quality, wound type, room cleanliness, and storyteller difficulty.

  • Treated wounds can still get infected at a reduced chance.
    • The chance multiplier is 85% at 0% tend quality, and linearly decreases to 5% at 100% tend quality.
  • Different wound types have different chances to get infected.
    • Frostbite, bite or burn wounds have a 25% chance.
    • Most other bleeding wounds have a 10% chance.
    • Bruises, cracks or missing parts cannot be infected.
  • Clean rooms with sterile tiles have a 32% chance multiplier. In contrast, a regular room without any dirt has 50%, and outdoors spaces have 100%.
  • Colonists are more likely to get wound infections at higher difficulties.

Animals have 20% of a colonist's chance to get an infection.

It is possible to have multiple infections simultaneously across different body parts. Each infection progresses at its own rate, while immunity against infections progresses at the same rate across the whole body.

Stages

Minor - Severity: 0 - 0.32

  • -10% Part efficiency
  • +5% Pain

Major - Severity: 0.33 - 0.77

  • -30% Part efficiency
  • +8% Pain

Extreme (Initial) - Severity: 0.78 - 0.86

  • -50% Part efficiency
  • +12% Pain
  • -5% Consciousness

Extreme (Advanced) - Severity: 0.87 - 0.99

  • -70% Part efficiency
  • Loss of Consciousness (max 10%)
  • +85% Pain
  • -5% Breathing

Extreme (Fatal) - Severity: 1

  • Death

Progression

  • When not immune, severity increases by 0.86 per day.
  • When immune, severity decreases by 0.667 per day.
  • Immunity increases by 0.62 per day when sick.
  • Treatment slows progression by a maximum of 0.53 per day.
    • This means that the disease will progress by 0.33 per day at this rate.

Prevention and Treatment

In order to prevent infections, make sure that people and animals that have open wounds are in a clean room when treated in the first place (e.g. no natural flooring apart from rock, no dirt or blood left to stay in the room, etc.). Although a clean room (or indeed sterile) won't fully nullify the chances of a wound getting infected, it will reduce the chance of an infection occurring - and is therefore a worthy precaution to take.

As with any other disease: Make sure that the patient is rested, well-fed, and treated whenever possible. Infections progress very quickly, and missing a treatment can be a very costly mistake. Due to the rate at which they progress, you'll need at least a competent doctor and medicine in order to ensure that the affected person survives their infections.

As a last ditch, if a colonist is about to die, don't hesitate to amputate the affected part. It's better to have a colonist missing a part or two than a dead one. They won't mind if you remove their infected parts, either.

Pawns with critically damaged and infected vital parts will need rest immediately at beds and receive the best healthcare available, to slow the disease down. Infections on that part kill much earlier than they usually do.

Treating Normal People (<40 Years Old)

You will need at least 35% average treatment quality to ensure that one doesn't succumb to their infected wound(s).

The following combinations of medicine skill and medicine type are capable of delivering 35% treatment quality, but you'll want to aim higher than this as these combinations are the bare minimum, and aren't guaranteed to work out in your favor (they don't take the doctor's journey or time to administer into account):

Treating the Elderly (80+ Years Old)

As usual, older colonists will have weaker immune systems and that translates to a 20% loss in Immunity Gain Speed. You should therefore execute heightened medical protocols to ensure that elderly people with infected wounds make it through the painful process.

To successfully treat an elderly colonist with an infected wound, they'll need to get at least 60% treatment quality on average for their infection. The following list again states the minimum combinations required to achieve this standard of treatment, but you should generally aim higher than these:

  • Level 2 Medicine skill and Glitterworld medicine
  • Level 7 Medicine skill and ordinary Medicine
  • Level 13 Medicine skill and Herbal medicine

Amputation

If you know that a colonist has a chance to die from an infection, it's best that you amputate the part. Colonists that reach 80-90% disease progression with their immune systems unable to catch up should have their infected part amputated immediately if possible.

Don't worry about amputations failing; they always succeed no matter how bad the surgeon or medicine used is. You can safely use herbal medicine to remove an infected body part. They do leave behind a bleeding wound, which needs tending, but cannot be infected (the body part being missing).

If the infection has progressed to over 97%, there is little to no chance your surgeons can successfully pull off an amputation in time. It's better to strip the sick colonist of their clothes and leave them to die (or euthanize them to make their imminent death less painful).

Part replacement

Besides amputation, you can also swap out the diseased part with a healthy one. If the surgery fails, however, you will risk another infection from the surgical cuts and stabs.