Giardiasis (Giardia lamblia)

Giardia lamblia (Giardia)Giardiasis, sometimes called 'beaver fever', is an infection of the intestinal tract. When a person gets sick from this infection it is called giardiasis. It is caused by the parasite Giardia.

Image Content Provider: CDC/Janice Haney Carr


Often, there are no symptoms. When symptoms do occur they will generally appear within seven to 10 days after a person becomes infected but can occur anywhere from three to 25 days after a person becomes infected. Symptoms may include diarrhea, stomach cramps, bloating, upset stomach, fatigue, and weight loss.


Giardiasis is spread by the fecal-oral route, either directly by person-to-person contact (e.g. diaper changing, sexual practices) or indirectly by eating or drinking fecally contaminated food or water. The infection can also spread by coming in contact with the feces of an infected animal. Fecal material can get into a person’s mouth by contact with the feces of an infected person or animal that is not followed up by proper hand washing. Individuals with weakened immune systems, such as those living with AIDS or cancer, or transplant patients receiving immunosuppressive drugs are more at risk of serious illness.


Specific antibiotics are used to treat Giardia infection.


Illness is preventable by protecting food and water from fecal contamination as well as practicing good hand hygiene, especially before and after using the bathroom, changing diapers, touching animals and before eating or preparing food.  Do not drink raw milk or raw milk products. Avoid drinking untreated surface water (eg. from lakes, rivers, springs or ponds). When travelling where the water supply may be unsafe, drink bottled water and avoid uncooked foods washed with unboiled tap water.

Manitoba Health Resources

For the Public

For Health Care Providers

Other Resources

Information for Travelers

Communicable Disease Control (CDC)
Public Health
Manitoba Health

4th Floor - 300 Carlton St.
Winnipeg MB  R3B 3M9  CANADA

Health Links – Info Santé
204-788-8200 or 1-888-315-9257