What kind of diseases can your dog get from swimming in lakes, streams, ponds, or rivers?
Swimming is an excellent form of exercise and fun for many dogs. However, in some lakes, ponds, and streams there are water-borne pathogens of potential concern. In general, the organisms found in outdoor water sources that can cause illness in dogs are the same ones that can potentially make humans sick. With only a few notable exceptions, most of these illnesses are not life-threatening, but they can cause gastrointestinal upset (typically vomiting and diarrhea) and other health problems.
Giardia and Cryptospori-dium are two microscopic organisms that are commonly found in fresh water throughout the United States. Both of these parasites can cause inflammation of the intestinal tract and diarrhea when ingested by dogs (or people) even in small numbers. Most dogs with healthy immune systems are able to recover from this infection but severe diarrhea may, in some cases, lead to dehydration and significant illness.
Puppies and older dogs with other underlying health issues may be more severely affected. Treatment with a specific antibiotic and/or de-worming medication, a bland, readily-digestible diet, and possibly fiber supplementation will likely be recommended by your veterinarian. Bathing your dog and removing all potentially contaminated feces from the yard is important to prevent him or her from becoming re-infected.
Leptospirosis is a less common, but more dangerous illness transmitted by bacteria that may be found in some contaminated water sources. It poses a significant health risk to both dogs and humans who come into contact with it, and may lead to fever, lethargy, vomiting, kidney failure, liver failure, and even death in some untreated individuals. Rapid treatment with appropriate antibiotics and supportive care by your dog’s veterinarian is important if this disease is suspected. The organism may be transmitted to other dogs or even people via contaminated urine, so early diagnosis and appropriate treatment is crucial. While there is a vaccine available for use in dogs, the decision to vaccinate should be made in consultation with your veterinarian.
Blue-green algae may be found in fresh or brackish waters and often appears as either foam, scum, or mats of red, green, or brown algae. Water contaminated with this organism may smell musty or foul and should definitely be avoided. If your dog’s fur becomes contaminated by this algae, it should be washed thoroughly. If signs such as skin rash, vomiting, diarrhea, weakness, or ataxia (dizziness and stumbling) develop, veterinary care should be sought immediately as this organism may produce toxins capable of affecting the kidneys, liver, intestines, and nervous system of dogs.
Swimming in lakes and streams is generally safe. Pay close attention to official sign postings that list hazards, and avoid foul-smelling or obviously contaminated water. Consider boiling drinking water for both yourself and your dog if backpacking with your furry companion in areas known to have high levels of Giardia, Cryptosporidium, or other infectious organisms. As always, consult with your veterinarian if you have specific questions about potential health problems, as well as both prevention and treatment of these various waterborne illnesses.