Malaria is prone there, so pop those anti malaria drugs. I took the, forgot the name, but you take one everyday for 1-2 weeks before leaving, and than once a week while in country and than a week or too after leaving the "infected" area. Some of the people I was with took the other "everyday" malaria pill and they had some serious side affects. Bad, bad sunburn, rashes and just plain vomiting. I had no side affects, a lot of the girls had the affects. But, if your friend is a doc I am sure she will figure it out.
Just make sure she always travels in groups, especially with males. The locals target females, especially ones by themselves. Most of the time they are just out to pinch their wallet, but you never know. Like I said before hard currency USD is the best, but if she is scared of taking so much cash, take a well known travellers check. The exchange booths rip you off on the "transaction" fee, but hey its Africa.
Make sure she has a Yellow International Immunization Card, same one we have in the military. She must have the Yellow Fever shot. She should also look into getting Typhoid; Rabies; Hepatitis A; Hepatitis B; Tetanus; Polio and Meningitis shots. It might sound over board, but Africa is a dirty place, and you never know what you might pick up.
Take a personal medical kit, other to what she is taking for the "patients". I just got one off REI.
If you need any other info just let me know.
Good Luck!
P.S. Have her seriously check out those two parks I mentioned. They are awesome. True Africa!