Giardia or Beaver Fever

Late Summer Bellyache and Gas? It might be Giardia
by Dallas Virchow, School of Natural Resource Sciences, University of Nebraska

Giardia trophozoite
Author's rendition of a
trophozoite of Giardia

Late summer bellyache and gas?...the problem may not be the chili dogs or barbeques.

What's the first microorganism probably seen under the microscope by von Leewenhoek, has tiny hair to propel it through your body, and only takes a few of them to give you a belly ache or worse? Giardia. Giardia is also resistant to the typical chlorine concentrations used in drinking or swimming pool water and can stay alive in the soil. Fortunately, this relatively large microbe that looks like a boogey-man with its flagella under the microscope (image right), can be filtered out of water. Fortunately too, giardiasis, once diagnosed, is easily treated with one of several prescription drugs.

Historically known as "beaver fever", 40 species of Giardia are now known to affect many kinds of rodents, amphibians, and mammals, including domestic cats and dogs, and humans. The common methods of infection are through contaminated water and inadvertent transmission of animal feces via the mouth. Giardiasis, was once thought of as a camper's disease. Campers under primitive conditions, such as lack of hygiene or water and contact with Giardia cysts through the droppings of wildlife, were often the ones that contracted the disease. Today, Giardia, is a disease most common in children under five, commonly thought to contract it through public swimming areas (pools, lakes, water parks) and day care centers. Each year there a thousands of hospitalizations and estimates are as high as 2.5 million cases of giardiasis in the US.

Once inside the stomach or intestine, Giardia cysts hatch into the boogey-men and affect how you absorb fats and sugars, sometimes causing lots of gurgling, belching and smelly gas. But the affects of giardiasis among people can vary widely from no symptoms or mild stomach upset to chronic diarrhea, abdominal pain, and weight loss.

The Centers for Disease Control Website at recommend the following prevention strategies:

  • Wash hands thoroughly with soap and water.

  • Wash hands after using the toilet and before handling food (especially for persons with diarrhea).

  • Wash hands after every diaper change and when working with children, even if you are wearing gloves.

  • Avoid swimming if experiencing diarrhea (essential for children in diapers).

  • Avoid water that might be contaminated.

For Campers:

  • Avoid drinking untreated water from shallow wells, lakes, rivers, springs, ponds, and streams.

  • If you are unable to avoid water that might be contaminated, then treat the water by heating it to a rolling boil for at least one minute (longer at high elevations).

With these preventions in mind during our summer swimming and camping activities, most of us can avoid the late summer belly-ache.

This resource appeared in the August/September 2003 NEBLINE Newsletter. For information on reproducing this resource or using any photographs or graphics, read the Terms of Use statement)

Return ArrowReturn for more resources -

University of Nebraska-Lincoln Extension in Lancaster County is your on-line insect pest and wildlife educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office