Requirements to enter Senegal

I'm working on planning a trip to Senegal in the next couple months and was wondering if anyone could help me by clarifying the requirements for entering the country, specifically in regard to health and vaccination. I've found some places online that say that you need proof of a yellow fever vaccination while other places say that you don't. I would appreciate any clarity that anyone may be able to provide as to whether this is necessary or not, and if it is, what I would need to prove that I have it.