Some people with giardia infection never develop signs or symptoms but still carry the parasite and can spread it to others through their stool. For those who do get sick, signs and symptoms usually appear one to three weeks after exposure and may include:
- Watery, sometimes foul-smelling diarrhea that may alternate with soft, greasy stools
- Fatigue or malaise
- Abdominal cramps and bloating
- Gas or flatulence
- Weight loss
Signs and symptoms of giardia infection may last two to six weeks, but in some people they last longer or recur.
When to see a doctor
Call your doctor if you have loose stools, abdominal bloating and nausea lasting more than a week, or if you become dehydrated. Be sure to tell your doctor if you're at risk of giardia infection — that is, you have a child in child care, you've recently traveled to an endemic area, or you've swallowed water from a lake or stream.
Oct. 13, 2015
- Leder K, et al. Epidemiology, clinical manifestations, and diagnosis of giardiasis. http://www.uptodate.com/home. Accessed Sept. 1, 2015.
- Munoz FM. Treatment and prevention of giardiasis. http://www.uptodate.com/home. Accessed Sept. 1, 2015.
- Levinson W. Intestinal and urogenital protozoa. In: Review of Medical Microbiology and Immunology. 13th ed. New York, N.Y.: The McGraw-Hill Companies; 2014. http://www.accessmedicine.com. Accessed Sept. 1, 2015.
- Giardia. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/giardia/. Accessed Sept. 1, 2015.
- Longo DL, et al., eds. Protozoal intestinal infections and trichomoniasis. In: Harrison's Principles of Internal Medicine. 19th ed. New York, N.Y.: The McGraw-Hill Companies; 2015. http://accessmedicine.com. Accessed Sept. 1, 2015.