What is giardiasis?
Giardiasis (GEE-are-DYE-uh-sis) is a diarrheal illness caused by Giardia intestinalis (also known as Giardia lamblia), a one-celled, microscopic parasite that lives in the intestine of people and animals. The parasite is passed in the stool of an infected person or animal. The parasite is protected by an outer shell that allows it to survive outside the body and in the environment for long periods of time. During the past 2 decades, Giardia has become recognized as one of the most common causes of waterborne disease (drinking and recreational) in humans in the United States. The parasite is found in every region of the United States and throughout the world.
What are the symptoms of giardiasis?
Symptoms include diarrhea, loose or watery stool, stomach cramps, and upset stomach. These symptoms may lead to weight loss and dehydration. Some people have no symptoms.
How long after infection do symptoms appear?
Symptoms generally begin 1-2 weeks after being infected.
How long will symptoms last?
In otherwise healthy persons, symptoms may last 2-6 weeks. Occasionally, symptoms last longer.
How is giardiasis spread?
Giardia lives in the intestine of infected humans or animals. Millions of germs can be released in a bowel movement from an infected human or animal. You can become infected after accidentally swallowing the parasite. Giardia may be found in soil, food, water, or surfaces that have been contaminated with the feces from infected humans or animals. Giardia is not spread by contact with blood. Giardia can be spread:
Who is at risk?
Everyone. Persons at increased risk for giardiasis include child care workers; children who attend day care centers, including diaper-aged children; international travelers; hikers; campers, swimmers; and others who drink or accidentally swallow water from contaminated sources that is untreated (no heat inactivation, filtration, or chemical disinfection). Several community-wide outbreaks of giardiasis have been linked to drinking municipal water or recreational water contaminated with Giardia.
I have been diagnosed with a Giardia infection. Should I worry about spreading infection to others?
Yes, Giardia can be very contagious. Follow these guidelines to avoid spreading Giardia to others.
What should I do if I think I have giardiasis?
See your health care provider.
How is a Giardia infection diagnosed?
Your health care provider will likely ask you to submit stool samples to see if you have the parasite. Because Giardia can be difficult to diagnose, he or she may ask you to submit several stool specimens over several days.
What is the treatment for giardiasis?
Several prescription drugs are available to treat Giardia. Consult with your health care provider. Although Giardia can infect all people, young children and pregnant women may be more susceptible to the dehydration resulting from diarrhea and should drink plenty of fluids while ill.
How can I prevent Giardia infection?
Practice good hygiene.
Avoid water that might be contaminated.
Avoid food that might be contaminated.
Avoid fecal exposure during sex.
My water comes from a well; should I have my well water tested?
If you answer yes to the following questions, consider having your well water tested.
Tests specifically for Giardia are expensive, difficult, and usually require hundreds of gallons of water to be pumped through a filter. If you answered yes to the above questions, consider testing your well for fecal coliforms or E. coli instead of Giardia. Although fecal coliforms or E. coli tests do not specifically test for Giardia, testing will show if your well has fecal contamination.
My child was recently diagnosed as having giardiasis, but does not have any diarrhea. My health care provider says treatment is not necessary. Is this true?
In general, the answer by the American Academy of Pediatrics is that treatment is not necessary. However, there are a few exceptions. If your child does not have diarrhea, but is having nausea, or is fatigued, losing weight, or has a poor appetite, you and your health care provider may wish to consider treatment. If your child attends a day care center where an outbreak is continuing to occur despite efforts to control it, screening and treatment of children without obvious symptoms may be a good idea. The same is true if several family members are ill, or if a family member is pregnant and therefore not able to take the most effective anti-Giardia medications.