Giardiasis is a common infection of the intestines. It is found all around the world.
Giardiasis is caused by a parasite. It can easily pass into humans after:
Giardiasis is more common in places with poor water or sewage treatment. Asia and South America have the highest infection rates. Risk is also higher for people who:
Some people do not have signs of illness. Others may have:
The infection can pass to others even if symptoms are not present.
The doctor will ask about your symptoms. They will ask about housing, health and travel history. The answers and a physical exam may point to an infection. The doctor will often test a sample of your stool to confirm giardiasis.
Others in your home will also need testing.
Medicines will treat the infection.
To lower your chances of giardiasis:
Wash your hands often and always:
When traveling overseas:
Avoid contact with stool during sex:
Treat water in swimming pools as recommended.
Centers for Disease Control and Prevention
IDSA—Infectious Diseases Society of America
Canadian Public Health Association
Giardiasis. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T113949/Giardiasis. Updated June 4, 2018. Accessed September 26, 2019.
Giardiasis. Kids Health—Nemours Foundation website. Available at: https://kidshealth.org/Nemours/en/parents/giardiasis.html. Updated July 2018. Accessed September 26, 2019.
Giardiasis. Merck Manual Professional Version website. Available at: https://www.merckmanuals.com/professional/infectious-diseases/intestinal-protozoa-and-microsporidia/giardiasis. Updated October 2018. Accessed September 26, 2019.
Parasites–giardia. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/parasites/giardia. Updated July 22, 2015. Accessed September 26, 2019.
Dental dam use. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/condomeffectiveness/Dental-dam-use.html. Updated August 12, 2016. Accessed September 26, 2019.
Last reviewed September 2019 by David L. Horn, MD, FACP
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.