Crew! Wanted to let you know that Dr. Don Wolfram handed me two articles that he pulled from a couple of medical journals about both Traveler's Diarrhea and also Malaria. They're both very extensive, and will yield a lot of information, and you may want to peruse them just to see what they have to say.
You can click here for the article on Traveler's Diarrhea, and here for the article on Malaria. Both articles are in PDF format, so you'll need an Adobe product to read them if you don't have it loaded onto your computer. If you need Adobe Reader, you can download it for free from Adobe's main web site, or by clicking here.