Giardiasis is a diarrheal disease caused by the microscopic parasite Giardia. A parasite is an organism that feeds off of another to survive.
Once a person or animal (for example, cats, dogs, cattle, beavers, etc.) has been infected with Giardia, the parasite lives in the intestines and is passed in feces.
Once outside the body, Giardia can sometimes survive for weeks or months. Giardia can be found within every region of the U.S. and around the world.
• Eating uncooked food that contains Giardia organisms
• Drinking water or using ice made from water sources where Giardia may live (for example, untreated or improperly treated water from lakes, streams, or wells)
• Swallowing water while swimming or playing in water where Giardia may live, especially in lakes, rivers, springs, ponds, and streams
• Swallowing Giardia picked up from surfaces (such as bathroom handles, changing tables, diaper pails, or toys) that contain stool from an infected person or animal
• Having contact with someone who is ill with giardiasis
• Traveling to countries where giardiasis is common
People become infected when they swallow the parasite. It is not possible to become infected through contact with blood.
• Diarrhea
• Gas or flatulence
• Greasy stool that can float
• Stomach or abdominal cramps
• Upset stomach or nausea
• Dehydration
Symptoms of giardiasis generally begin by having 2 to 5 loose stools (poop) per day and progressively increasing fatigue.
Other, less common symptoms include fever, itchy skin, hives, and swelling of the eyes and joints.
Over time, giardiasis can also cause weight loss and keep the body from absorbing nutrients it needs, like fat, lactose, vitamin A, and vitamin B12.
Some people with Giardia infections have no symptoms at all.
Anyone can become infected with Giardia.
People more likely to become infected include:
• Children in child care settings, especially diaper-aged children
• Close contacts (for example, people living in the same household) or people who care for those sick with giardiasis
• People who drink water or use ice made from places where Giardia may live (for example, untreated or improperly treated water from lakes, streams, or wells)
• Backpackers, hikers, and campers who drink unsafe water or who do not practice good hygiene (for example, proper handwashing)
• People who swallow water while swimming and playing in recreational water where Giardia may live, especially in lakes, rivers, springs, ponds, and streams
• International travelers
If you think you have giardiasis contact your healthcare provider.
Your healthcare provider will ask you to submit stool samples to see if you are infected.
Because testing for giardiasis can be difficult, you may be asked to submit several stool specimens collected over several days.
• Practice good hygiene
• Avoid eating food that may be contaminated
• Avoid water (drinking or recreational) that may be contaminated
The risk of humans acquiring Giardia infection from dogs or cats is small.
The exact type of Giardia that infects humans is usually not the same type that infects dogs and cats.
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