Beaver Fever is a disease that dogs and people can get by drinking water from a contaminated source, such as a pond, a lake, or even a puddle. The disease is actually called giardiasis, and it is caused by a microscopic single-celled parasite called Giardia, that can infect the intestines of people and animals.
Giardia is found in bodies of water across North America and the common name for this disease in people, "beaver fever", originated when it was observed that beavers in beaver-dammed waterways could spread the parasite. It is thought that the organism comes from the feces of infected wild animals, including rodents, and also from pets and humans. Licking their paws after walking in a contaminated area may also infect pets, especially dogs. This parasite has been found in municipal water supplies in some regions, which may explain how some indoor housecats develop giardiasis. The giardia parasite is extremely hardy and can survive outside the host for long periods of time even when the environment is cool and damp.
Giardia is an important parasite for a number of reasons. It poses a risk to human health because it can be transmitted to people, causing severe gastrointestinal disease, especially in immunocompromised people, including the elderly, newborns, pregnant women, and cancer and AIDS patients. In some instances, infected individuals can carry this parasite without any signs of illness. It also affects pets and can cause vomiting and significant diarrhea. The abdomen can also be gassy and bloated. In pets that show no clinical signs, the parasite can nevertheless be harmful by robbing the intestines of essential nutrients during digestion, causing weight loss or lethargy. Giardia has also been associated with allergies in some species.
Since it is almost impossible to keep dogs and outdoor cats from drinking water outdoors, it is important to have your veterinarian test your pet's stools on a regular basis, particularly at the end of the summer. There is also a new vaccine available for dogs to prevent this disease that is safe and easy to administer. Consult your veterinarian about this vaccine and other aspects of this disease.