Skip to main content

Guard against getting giardia

Although it looks clean and pure, rivers like this could be contaminated with the giardia parasite.
Although it looks clean and pure, rivers like this could be contaminated with the giardia parasite.
L. Shuttleworth

They’re waiting for you out in the woods, looking for a nice new home in your body—no, not body snatchers from outer space--giardia lamblia parasites.

In Canadian lakes and rivers

You may have heard of giardia and thought only people travelling outside of North America were in danger of falling sick from it. Or you may think the beautiful, pristine lakes and rivers of Canada’s wilderness are free of giardia. You’d be wrong on both counts.

Where there are beavers, there is giardia

Unfortunately, where there are water-loving mammals such as beavers, moose, and muskrats, there is often giardia. Giardia cysts live in the feces of these animals. The cysts survive after the animals expel them into the water. Then along come hapless humans, thinking the river or lake water looks clean and can be drunk without being filtered or treated.

1-2 weeks to incubate

Once you have the giardia cysts in your body, it takes between 1 and 2 weeks for them to start affecting your health. Some people don’t get sick, but if you do come down with symptoms, you’ll experience diarrhea, weakness, stomach cramps, loss of appetite, and weight loss.

Your doctor will ask you to supply three days’ worth of stool samples before she or he writes a prescription for the medication that usually kills giardia infections. Or you can go to a traditional Chinese doctor for acupuncture and medicinal herbs. (This is the treatment that cured me during my recent month-long ordeal with giardia.)

Filter and treat all water in the wilderness

One sip of contaminated water when you’re on a canoe or hiking trip is all it takes to get really sick. Therefore, to guard against getting giardia, do not drink any water on a wilderness trip unless it is filtered or treated. You can buy easy-to-use filters at outdoor supply stores. They attach to your water bottle, and you can pump the water from the lake or river, through the filter, and right into your water bottle.

Chlorine tablets dissolve in your water bottle, and in 30 minutes you have clean drinking water.

If you’re really nervous about the water (for instance, you see beavers swimming around your campsite), use chlorine and a water filter for extra protection.

See the Health Canada website for more information about giardia: