Giardia lamblia (or Giardia intestinalis), the parasite that causes giardiasis, is found in all parts of the world. But your chances of becoming infected are highest in areas in which water treatment facilities are limited or general sanitation is poor. When traveling in these places or whenever you're uncertain about water quality, take these precautions:

• Use only boiled or bottled water for drinking, washing your hands, and brushing your teeth.
• Avoid raw fruits and vegetables whenever possible. (They may have been washed in contaminated water.) If you must eat them raw, peel them first.
• Don't use ice that may have been made from contaminated water.