Prevention

No drug or vaccine can prevent giardia infection. But commonsense precautions can go a long way toward reducing the chances that you'll become infected or spread the infection to others.

• Wash your hands. This is the simplest and best way to prevent most kinds of infection. Wash your hands with soap and water for at least 20 seconds after using the toilet or changing diapers, and before eating or preparing food. When soap and water aren't available, you can use alcohol-based sanitizers. However, alcohol-based sanitizers aren't effective in destroying the cyst form of giardia that survives in the environment.
• Purify wilderness water. Avoid drinking untreated water from shallow wells, lakes, rivers, springs, ponds and streams unless you filter it or boil it for at least 10 minutes at 158 F (70 C) first.
• Wash produce. Wash any raw fruits and vegetables with safe, uncontaminated water. Peel the fruit before eating it. Avoid eating raw fruits or vegetables if traveling in countries where they may have contact with unsafe water.
• Keep your mouth closed. Try not to swallow water when swimming in pools, lakes or streams.
• Use bottled water. When traveling to parts of the world where the water supply is likely to be unsafe, drink and brush your teeth with bottled water that you open yourself. Don't use ice.
• Practice safer sex. If you engage in anal sex, use a condom every time. Avoid oral-anal sex unless you're fully protected.