Frost rot

Frost rot is caused by a heat seeking fungus, which will start to grow on any exposed bare skin that touches it. The fungus seeks warmth, and grows towards it. Towns, campfires, animal dens, it doesn't matter. It will find you.
Once you are infected, you must burn the affected area or treat it with fungicide. Within a 24 hours it will penetrate and grow into your flesh, attempting to reach your bones. Frost rot will then slowly eat your flesh, and grow towards the core of your body, the warmest part.
The only thing to do at this stage is to amputate, if it is affecting a limb. Once it reaches your core it may have already killed you depending on the route it takes, if it grows from the legs it will have destroyed your lower organs, if your arm it might reach your heart, and stop it. Either way a gruesome death awaits you if you don't amputate.
Once the fungus has killed it's host, it will consume it and stay with it as long as it is still warm, unless another source of warmth is detected, it will continue consumption until nothing is left.

Transmission & Vectors

Bare skin contact with the fungus or an infected individual.

Causes

If you touch the fungus with your bare skin it will (usually) get spores on you, which will then start growing.

Symptoms

A grey fungus that grows along the skin, slowly progressing to the core of the body.
The victim will have a fever, and be in much physical pain.
Possible Hemorrhaging, and organ failure.

Treatment

Cauterise the affected area or else you will have to amputate if it's on a limb.

Prognosis

"Pretty screwed m8"
You will probably not notice you are infected until a day after, at which point it is too late for the first treatment, so you'll need to get a limb cut off.

Affected Groups

Most living things are fair game to this fungi. This of course excludes insects, plants, and cold blooded creatures.

Prevention

Certain pastes on the skin can kill the spores before they get into your skin. Clothing should be worn and water should always be boiled when you're in the country this fungus is native to.

Epidemiology

Through skin to skin contact with the infected.

History

When the Mregians arrived on Nylicert, they took over the northern most region, and discovered that a deadly fungus was frozen in the ice there. After an epidemic, measures were taken to make sure this deadly fungus never escaped the frost, the region was put under quarantine, and fields of weeds resistant to the fungus were planted all over it, especially along the border of the region.
At first, people thought it was the cold of the north that caused it, and so it was called "Frost rot".
Today the fungus seems to be extinct, but a there are specimens still in labs as a vaccine or cure is researched to stop this deadly fungus from causing another epidemic or even a pandemic.

Cultural Reception

The people that live in the North of Nylicert had to live with this fungus for years, and had to plant fields of a remarkably resilient weed with beautiful blue flowers that bloom in the summer. Fields of this weed now surround the historical cities in the region.

Type

Fungal

Origin

Natural

Cycle

Short-term

Rarity

Extremely Rare