Yeah, I learned the hard way. Back in the 80's, I contracted hookworm on a cruise ship (no idea which island) and it was misdiagnosed when I got back to Ohio. Luckily enough, on my second visit to the doctor a second doctor happened to stop in and countered the useless and possibly harmful treatment I was receiving by the first doctor. A short treatment with the appropriate treatment quickly solved my problem.
We both still go barefoot on the hot sunny sand, even on the shoreline - no real risk there, it is not a breeding environment. It is in those shady, moist areas that pose the most risk. Use sandals in those places for sure!