Wet weather puts dogs, livestock at risk of infection


The recent rainy weather reminds us that a species of bacteria called Leptospira thrives in warm, moist conditions and can lead to a potentially life-threatening infection called leptospirosis. 

There are multiple strains of Leptospira bacteria, and dogs are the most commonly infected companion animal, but livestock are also susceptible. Several wild animals including skunks, racoons, deer, and rodents can be a source of infections for dogs. 

The bacteria are normally passed when exposure to infected urine or tissue comes in contact with mucous membranes or open wounds, but it can be transmitted through breeding or intrauterine. Leptospirosis is zoonotic, which means people can also become infected from exposure to an infected animal but most cases of Leptospirosis in people stem from coming in contact with infected recreational water sources.

Once the bacteria enter the bloodstream, the kidneys and liver are the most commonly affected organs. Increased thirst and urination, jaundice, lethargy, and fever are common, but not every infected dog will show all these symptoms. 

Routine blood tests will reveal the degree of kidney and/​or liver involvement, but they do not confirm an infection. Special tests are needed to diagnose and some tests need to be run before administering antibiotics to avoid a false negative result. 

If your dog has symptoms of Leptospirosis, your veterinarian may start treatment before the tests come back and will need to take precautions to ensure you and your family are not exposed. If your pet is sick enough to warrant hospitalization, he may need to be in isolation to minimize exposure to other dogs and protect hospital personnel taking care of him. 

There are two phases to treatment and generally infected animals respond quickly to antibiotic therapy. Once your dog is through the acute phase of the infection, treatment with another antibiotic will be needed for an extended period to clear the bacteria from the body.

Routine vaccination can prevent serious infection from the most common species, called serovars. The vaccine has an undeserved reputation for causing vaccine reactions, and misinformation persists about which dogs should be vaccinated. 

Northwest Ohio and southeast Michigan have conditions that favor the bacteria and even suburban backyard dogs have the potential to be exposed to the bacteria so your veterinarian may recommend the vaccination even if your dog does not run through the woods. The immunity to the bacterium is not long lasting, and regular boosters are needed for protection. If you suspect your dog may be infected, seek immediate treatment from your veterinarian.

Questions for Dr. Gary 
Thompson can be emailed to