YOU HAVE DIED OF DYSENTERY
Answer: CONTRACT
Liam Thomas, Olga Vinogradova

This is a puzzle about word transformations. Each symptom clues a different transformation which can be applied to exactly one of the 8 words for each patient and produce a valid word. Once we're done assigning symptoms to words, we're left with three words: "CATCH", "DISEASE", and "EIGHT". This is a cluephrase for the answer, indicating that the answer is a eight-letter word that means "Catch disease".

Chills: Prepend COLD.COLD BLOODCOLD SHOULDERCOLD SWEAT
Dehydration: Remove HHO.THUMBHOLETHOUGHHOARHOUND
Dizziness: Reverse the word.DESSERTS → STRESSEDDELIVER → REVILEDREGAL → LAGER
Drowsiness: Add a Z.QUARTZCZARZONE
Flushed Skin: Make it red.BLACKBERRY → RASPBERRYEMERALDRUBYVIOLETSROSES
Stuttering: Duplicate a letter.LATTECORRALSCARRED
Voice Loss: Remove all vowels.CRAYPOTSCARYSTAY
Remaining Words:CATCHDISEASEEIGHT