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The question: We just returned from our last camping trip of the summer and I have awful stomach cramps and diarrhea. I thought it would get better after a few days but it's not letting up. Is this beaver fever and if so, what can I do?

The answer: The warm memories of a summer camping trip can quickly fade away if we become sick soon after returning. While getting away for a little R&R in the great outdoors can be enjoyable and good for our health, there are some potential hazards to be aware of.

Based on your symptoms, it certainly sounds like you may have picked up Giardia lamblia, the waterborne parasite that causes "beaver fever." Giardia is spread by small cysts found in contaminated soil, water or food. It's known as beaver fever because our national animal is a common host of the parasite, but any mammal can carry and pass on the parasite through their feces, including humans.

In the outdoors, it is mostly found in streams and lakes so if you've ingested water either while swimming or bathing, it may be the source of the infection. While Giardia is a very common cause of travellers' diarrhea, it can also lead to outbreaks in daycares and food establishments.

The parasite infects the intestinal lining and can cause diarrhea, bloating, gas, and abdominal cramps. Generally, symptoms start about a a week after exposure and resolve on their own. In rare cases, the infection can carry on for longer and lead to severe symptoms such as fatigue and weight loss. Children under five, seniors, and people with weakened immune systems are at highest risk for persistent infection.

If your symptoms last longer than a few days or you're having severe diarrhea, fever or pain, get checked out. Your doctor can order a stool sample that tests for Giardia and other types of parasites that cause diarrhea. Since the presence of the parasite can occur at variable times, you will need to submit at least three samples to ensure an accurate test.

For difficult cases, antibiotic treatment is warranted. If one round of antibiotics does not help, a different type of antibiotic or a longer course of treatment may be required. To prevent passing Giardia on to someone else, treatment is useful for children who attend daycare and those who work with food.

When dealing with any diarrheal infection, remember to drink plenty of water to rehydrate and replenish your body's stores. Giardia can also affect how the intestines absorb nutrients. As a result, lactose can be very difficult to digest and you may need to decrease your intake of milk products for the first weeks following an infection.

These simple precautions will also help you avoid getting Giardia on your next camping trip:

  • avoid drinking untreated water
  • always wash your hands with soap after using the washroom and before food preparation
  • if you are hiking and need to use stream water for drinking, be sure to boil it for at least 10 minutes, use a water filter or invest in purification tablets
  • most Canadian parks will monitor for high Giardia content in their water systems, so take extra precautions if this is the case.

Dr. Sheila Wijayasinghe is the medical director at the Immigrant Womens' Health Centre, works as a staff physician at St. Michael's Hospital in their Family Practice Unit and at Hassle Free Clinic, and established and runs an on-site clinic at Women's Habitat Shelter in Etobicoke.

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