I agree with you that the fever is kinda overpowered. Obviously an infected wound should be lethal when left untreated but I think it should take at least two or three days. Playing mp with friends right now and a friend basically died three in game hours after getting an infected wound. He practically just got back to base and immediately got a fever and just straight up died. No time for the rest of us to even attempt an emergency run for some meds to help him.
I think there should be some wind up time before the infection and fever begin to kill you, or it should drain health more slowly to allow for a chance to take medicine and heal. Or have a separate disease moodle for infection that will increase and trigger the nausea/fever which then kills you.

I ve gotten it by being too cold apparently even though I have so much clothing from brita and vanila ...

Fever effects are untouched in Dynamic Traits. Once you reach the Fever Moodle (sickness level 4) the vanilla effects applies which are the ones that kills you.

The Fever Moodle appears once the foodSickness value (called that way internally) reaches a value of >=90. If you manage to lower it to 89 you won't die. To lower it you can simply wait as it lowers itself as the time passes (in order to survive you will have to probably sleep to recover HP, otherwise you don't have enough time to recover HP while it goes to 89) or eat lemongrass.
Up to this point is all vanilla.
Now, how Dynamic Traits enters into the equation, DT will increase that foodSickness based on certain circumstances, for Wounds it will do it using the "infected" flag that each wound has (vanilla), if it is infected, then the foodSickness increases, if not, nothing happens. foodSickness increases more when it is a new wound and gets lower increases the more the wound is healed.
Desinfected bandages completely prevent infection to even appear (so no sickness). Antibiotics removes the infection but doesn't prevent it to appear again.

引用自 ジャッキー・ザ・トキ：

I ve gotten it by being too cold apparently even though I have so much clothing from brita and vanila ...

This has nothing to do with Dynamic Traits. If the game deciced you were cold, that's how the game calculates that. Dynamic Traits doesn't change, touch or even uses those things at all.