Infection
Contagion
noun, verbal noun, の adjective
The feeling of dye, covering your body, is the feeling of nasty germs and diseases penetrating your skin, getting inside of you. This is an infection, and it's gross.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
歯周病は感染症の一種だとは知りませんでした。
I didn’t know that periodontitis is a type of infectious disease.