CONSIDERING IVY IS ABLE TO SAFELY TOUCH THE ONE PERSON WHO CAN SPREAD THE DISEASE TO HER.....LMAO...anyway i figure damon is PROBABLY going to infect ivy somehow so !!! maybe when its in its very early stages she tries to clean it/encourage it to heal with some aloe or bloodwood sap or something and that just ends up infecting her

and then they can try to find out how to heal it together