Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

University of Illinois at Urbana-Champaign

U of I logoCollege of Veterinary Medicine

Back to search page.

This Dog Won't Hunt: Leptospirosis Affects Any Breed


Pet Column for the week of July 5, 2011

Related information:

Services - Public Health

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Andrea Lin
Information Specialist

At one time leptospirosis was known as a disease primarily contracted by hunting dogs that swim in lakes and ponds. While it is true that the bacteria which cause this disease can contaminate any freshwater source, leptospirosis is also spread by other means and should be a concern for all dog owners.

Dr. Carol Maddox, a microbiologist with the University of Illinois Veterinary Diagnostic Laboratory in Urbana, says leptospirosis outbreaks periodically make headlines when people become ill after swimming in lakes, but most owners may not know that the disease occurs frequently in dogs.

"People tend to associate this disease with contaminated lakes," says Dr. Maddox, "but more cases are caused by exposure to raccoons than by contaminated water sources."

The diagnostic lab and the Illinois Natural History Survey have monitored leptospirosis in small mammals at Allerton Park, a 1,500-acre natural area near Monticello, Illinois. There it is estimated that about half of the raccoons and opossums have had or currently have leptospirosis. Dogs may contract the disease from areas with a lot of raccoon activity, such as under birdfeeders and around trash cans and dumpsters at many parks.

Although leptospirosis can easily be eliminated with antibiotics, the infection often goes undetected in dogs until it has caused severe kidney or liver damage. An infected dog may initially show no signs of illness or may be mildly depressed or have a fever. Early treatment is important to prevent kidney and liver damage, which may be irreversible.

There are likely more cases of leptospirosis than reported because antibiotics prescribed to address vague signs of illness will eliminate the disease without there being a definitive diagnosis. Dr. Maddox says approximately ten percent of specimens submitted to the diagnostic laboratory from suspect canines are positive. Many of these dogs seldom leave their housing development but encounter the bacteria from retention ponds visited by local wildlife.

Because people can be infected with leptospirosis, it is important to wash your hands if your dog is sick. Leptospirosis bacteria are shed in the urine. In most people, symptoms resemble a mild type of flu, but for immune-compromised people, such as the very young or very old, consequences can be much more serious. Always keep young children away from sick pets.

In addition, a dog with leptospirosis should be isolated from other dogs in the household to prevent the spread of the disease. Dr. Maddox says there have been no cases in east central Illinois of leptospirosis in cats.

As with many diseases, the best way to keep your dog safe from leptospira infection is to prevent it. Dr. Maddox highly recommends vaccinating dogs in the Urbana area against leptospirosis. Vaccines available are fairly safe as well as effective.

So whether you have a retriever that goes hunting or a pug that visits the park, consider vaccinating to help prevent leptospirosis in your pet and your family.

For more information about this disease and the vaccination, please contact your local veterinarian.