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Prevention
By Mayo Clinic staffNo drug can prevent giardia infection. Still, common-sense precautions can go a long way toward reducing the chances that you'll become infected or spread the infection to others.
For your own safety:
- Wash your hands. This is the simplest and best way to prevent most kinds of infection. Wash your hands after using the toilet or changing diapers and before eating or preparing food. Scrub your hands briskly with soap and warm water for at least 15 seconds. For children, this is about as long as it takes to say the ABCs or sing the "Happy Birthday" song. Rinse thoroughly, allowing the water to run down your hands, and then dry your hands with a disposable paper towel. When soap and water aren't available, alcohol-based sanitizers containing at least 60 percent alcohol are an excellent alternative.
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Purify water If you're not sure water is safe to drink, you can purify it using one of these methods:
- Heat or boil water to at least 158 F (70 C). Ten minutes should be enough to kill any parasites.
- Use a water filter. The Centers for Disease Control and Prevention recommends a filter having a pore size of 1 micron or smaller or one that has been rated by the National Science Foundation (NSF) as effective for cyst removal.
- Don't rely on chlorine or iodine water purification tablets — they're not always effective against giardia parasites. Iodine disinfection, for example, must be carried out for at least eight hours.
- Leave no trace. If you're camping without access to a toilet, bury your waste and your pet's at least 6 inches (15 centimeters) deep and 150 feet (about 46 meters) from a water source. People with portable toilets should use sewage dump points.
- Keep your mouth closed. Try not to swallow water when swimming in pools, lakes or streams.
- Be wary of tap water. Each year in the United States, about 250 people in every 10,000 get giardiasis from public drinking water. Water can become contaminated if standard treatments aren't effective or natural events such as flooding overwhelm treatment systems. If an outbreak of giardia infection occurs in your area, buy bottled water or boil or filter tap water before you use it.
- 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, and avoid raw fruits and vegetables, even those you peel yourself.
- Practice safer sex. If you engage in anal sex, use a condom every time. Avoid oral-anal sex unless you're fully protected.
Giardiasis is extremely contagious. If you're infected, these measures can help keep others safe:
- Wash your hands. Scrub your hands with soap and warm water for at least 15 seconds after using the toilet and before handling food. If possible, have a friend or family member prepare meals until you're free of infection. Keep in mind that you can spread the parasites for several weeks after you stop having problems.
- Stay out of the water. Avoid all types of recreational water — pools, hot tubs, whirlpool spas, lakes and streams — for at least two weeks after your diarrhea has stopped. You can continue to spread the infection even if you no longer have symptoms.
- Be sex-safe. Avoid having anal or oral-anal sex until you're free from infection.
