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What is Giardia infection?

Giardia infection (giardiasis) is a disease of the intestines caused by the parasite Giardia lamblia.

Giardia symptoms

  • Chronic diarrhea
  • Stomach cramps
  • Bloating & gas
  • Greasy stools

Symptoms can begin between three to 25 days or longer after contact with Giardia. Many people with Giardia do not have symptoms. A person with giardiasis can transfer the infection as long as he has the Giardia parasites.

Spread of Giardia

Person to person spread happens by hand to mouth transfer of the Giardia parasites from the stool of the infected person. You can get Giardia by eating foods or drinking water that has been contaminated with stools of infected humans or animals. Open waters like lakes, rivers, ponds or streams may have Giardia from stools of infected people and animals. Chlorination of swimming pools and spas does not kill Giardia. Another way to get infected is through anal sex.

Who can get Giardia infection?

Anyone can get Giardia infection. People at higher risk for Giardia infection are:

  • children in child care centers and adults who attend to these children
  • people in close contact with a Giardia-infected person
  • travelers to foreign countries where food and water may be contaminated with Giardia
  • men having sex with other men

Treatment of Giardia infection

Talk with your health care provider regarding appropriate treatment for Giardia infection. If a family member or close contact has the same symptoms, consult with your health care provider or the local health department for recommendations. If you are a food handler, health care or child care provider, call Contra Costa Public Health at 925-313-6740 for specific recommendations.

How to prevent Giardia infection

  • Wash hands before and after handling food, and before eating.
  • Wash hands after using the bathroom and after handling diapers.
  • Avoid drinking water from unfiltered sources, such as streams, rivers, lakes and ponds.
  • When in a foreign country, drink bottled water that has been treated and filtered.
  • Keep children with diarrhea out of swimming pools. Have diapered children wear tight diaper covers in swimming or wading pools.

Visit the Centers for Disease Control and Prevention for more information.