This addon will add 3 diseases into your minecraft world. One is the end disease, it will corrupt your body, another is nether disease which will lower your body immunity, last one is the overworld disease, which will zombify you.
Select version for changelog:
Changelog
Changed the nether disease from giving the player some effects into lowering your immune system so you will get diseases easier
Added Rabies a disease that is obtainable by getting hit by a wolf
Now the blood test determines the most important disease to cure once done
Added face mask
Added logic
Bug fixes
Maybe you should try to make and addon where you can be infected by a zombie or a syringe with the virus in it to make the player a zombie.