This contamination now allow the virus to move into another living medium (the one who actually ate the potato).
After the virus enter the eater's body, it will start to reproduce itself and caused several symtoms during the period where the antbodies inside the host's body is fighting it.
Because the kidneys cant get rid of all toxins in the body.
It's a fun, and interesting thing to do. It's a great help towards your community and you benefit in the end with people and working skills. It's also great if you need some extra curriculars for your college applications.