Always use latex condoms to reduce the risk of HIV and other sexually transmitted diseases. Don't drink beverages with ice. Don't eat dairy products unless you know they have been pasteurized. Don't share needles with anyone. Don't swim in fresh water.
Salt water is usually safer.
Iodine tablets and water filters to purify water if bottled water is not available. See Do's above for more details about waterfilters. Sunblock, sunglasses, hat.