Beaver fever is one of the most common causes of diarrhea in B.C. It is caused by the parasite, Giardia lamblia, which can survive in cold water for long periods of time. This parasite infects the digestive tract of many mammals, including humans. It affects 200 million people a year around the world and results in 2,000 deaths world-wide. This is because in developing countries, in the frail elderly, and in those with compromised immune systems people are more vulnerable to the infection and the dehydration that results from beaver fever.

Beaver fever is passed along fecal-orally, meaning that mouth-contact with water or food contaminated with infected feces is the most likely way it is caught. People who are out hiking and back-packing are at highest risk due to drinking untreated water. Dogs, cats, horses, cows, etc. can all be reservoirs for the parasite.

People with beaver fever have a loss of appetite, upset stomachs, and diarrhea. As with the name, there is a fever. These symptoms don’t usually appear for at least 1—2 weeks after infection with the Giardia parasite. The ill effects come and go and usually tend to eventually disappear on their own.

People who are infected with Giardia and can’t control their bowel movements should not go to work or school until they can, as it is extremely contagious. Stool can remain infected for months after all symptoms have disappeared and so good hand-washing is a must. Most people will recover without any formal treatment after the parasite has run its course.

To avoid beaver fever, the best thing to do is boil any water before you drink it while in the outdoors. Carrying iodine tablets with you when traveling in developing countries is a good idea as they can be added to any water to kill off disease-causing parasites like Giardia. You can try adding a small amount of bleach to water that you are wishing to drink, but it does not always kill Giardia.

The ratio is 9 drops of bleach to a gallon of water and you should leave it to sit for at least 30 minutes before drinking it. If at that point the water is still cloudy then another 9 drops of bleach can be added. There are filters whose pores are small enough to filter out the Giardia cysts, but the pores must be less than one micron in diameter.

Filters need regular and thorough maintenance to be relied upon. If you would like more information, the B.C. health guide can be found on-line or you can contact your local Environmental Health Officer.