Well, yes that’s true. However, a lot of people who are native to Africa have some immunity to it, such as anyone who has the sickle-cell trait. So people who have lived there for generations have some protection built into their immune system for it. That’s why not every African bit by a mosquito that carries it gets malaria.
Megs isn’t native to Africa. I don’t know what her genetics are–such as if she carries the sickle-cell trait–but I imagine that they’re going to take precautions just to be on the safe side.