Leptospirosis and Your Dog: What are the Facts?

What do you know about Lepto? Many of you may have never heard of this at all or some of you may be asking “Is that the one for the ponds?” There is a lot of misinformation out there and about this disease and its prevention so let’s dive into the facts and why this is a no-brainer vaccination for your dog.

What is Lepto and where does it come from?

Leptospirosis is a bacterium that is spread to dogs from rodents, skunks, raccoons, possums, cows, pigs, horses, etc. Most mammals can contract and be a source of infection for other animals. It is spread primarily through the urine of these animals although dogs can become infected through bite wounds, ingesting infected tissues, or through the placenta in pregnancy.

You may have been asked by your veterinarian if your dog frequently visits lakes or streams. This is because the lepto bacteria prefer warm moist environments and are often found in stagnant or slow-moving water. This includes rain puddles, ditches, and those low-lying areas of your yard. Once there, they can persist in that water for months, so the peak times for animals to contract this disease are the rainy seasons from July through November. Swimming in ponds or lakes is not the only way dogs contract this disease, however, and more and more we are seeing positive cases that have no connection to water sports. New York City has a high rate of positive leptospirosis infections in dogs reported from all 5 boroughs with the major source of infection being from rats in urban areas.

In our community of Towne Lake and the rest of Cherokee county- we have suburban neighborhoods and golf courses that become breeding grounds for rats and mice, and we also have plenty of wooded lots with wildlife like racoons and possums coming right up to our backdoor. We don’t have to go very far or look very hard for the right type of animal or condition to spread leptospirosis.

So why is Lepto so bad?

Once in the body, Leptospirosis begins to multiply and spread quickly. The bacterium penetrates into the kidneys and cause severe kidney injury or failure. It damages the liver causing complete liver failure. We can see toxicity in the lung tissue and cause your dog’s lungs to bleed. It can affect the way dogs can clot their blood, and we can see severe blood loss and the shutdown of multiple organs.

The symptoms you see at home can be varied and range from vague to severe.

The most common symptoms we see are:

• Anorexia
• Vomiting
• Drinking a ton of water
• Peeing too much or having accidents in the house
• Weight loss

These symptoms can be vague and progressive so the disease may spread quietly before dogs are able to be seen by their veterinarians and have diagnostics performed.

Other times the symptoms are swift, and your veterinary staff have very little time to get to the diagnosis and treatment before your dog has severely decompensated. In the peracute or acute forms we see:

• Fever
• Shivering
• Muscle tenderness
• Vomiting/diarrhea
• Nosebleeds, bloody stool, or other signs of internal bleeding
• Acting severely depressed and anorexic
• Sudden death

The sad truth about this deadly disease doesn’t end here I’m afraid. Leptospirosis is a zoonotic disease meaning it can spread to people. So, while you are caring for your sick pet and unsure what may be wrong, they may be unknowingly transmitting their disease to you. The signs for humans can also be vague: fever, headache, vomiting, or rash. They may be self-limiting flu-like symptoms or progress rapidly to a fatal disease.

How do we prevent Lepto?

So, if all that sounds completely terrible, the good news is we have ways to prevent this deadly disease! The leptospirosis vaccine is given once a year after a 2 booster initial series and protects dogs from the 4 most common serovars of Leptospirosis.

This vaccine is safe. Although reactions to this vaccine can occur, they are typically no worse than what pets can experience with any other vaccine which include facial swelling, hives, vomiting or diarrhea. These are treated with injections of Benadryl and sometimes steroids and typically pose no major threat to your dog’s life.

The misinformation stems around the fact that we used to consider this a lifestyle vaccine, meaning that if you didn’t believe that your dog contacted wildlife enough it would not be routinely given. In the past, we did see more reactions to this vaccine than to any other. With continued advancements in vaccine technology, today we rarely see reactions to the leptospirosis vaccine.

In fact, in 2024 AAHA (American Animal Hospital Association) updated their vaccination guidelines which now states “the leptospirosis vaccine should be administered annually to all dogs starting at 12 weeks of age, regardless of breed” citing that “any dog that goes outdoors whether in an urban or rural setting can be exposed to leptospirosis.”

Are you convinced?

So now I hope you understand the full extent of what Leptospirosis can do to your dog. We have a safe and reliable way to protect your pet, you, your children, and your elderly parents from contracting this terrible disease. For me, this is a no-brainer decision to protect my personal pets and all my patients as well. I hope you agree!

Lindsay Baker, DVM

To read more articles by Dr. Lindsay Baker, click here to explore the blog: https://www.animalhospitalofwestwoodstock.com/blog/