You’ve probably heard the word leptospirosis at your vet’s office or read it on your pet’s vaccination record, but what exactly is it, and why does your dog need to be protected from it? 

Leptospirosis (or “lepto” for short) is a serious bacterial disease that affects both animals and people. All dogs are at risk for lepto, whether they live in urban, suburban, or rural environments. The bacteria, found worldwide in water or wet soil, spreads through the urine of infected animals and wildlife. 

“Leptospirosis can progress rapidly and affect multiple internal organs, including the kidneys and liver,” says Dr. Karen O’Connor, Regional Veterinary Medical Director of Pet Paradise + NewDay Veterinary Care. “Vaccination against leptospirosis primes your pet's immune system to respond and helps to protect them from the disease.” 

Once infected, lepto can cause fever, vomiting, and lethargy. In severe cases, it may lead to lasting liver or kidney damage or escalate to become fatal. In fact, more than 80% of dogs with leptospirosis develop serious kidney problems, and even dogs that recover may still be at risk of chronic kidney failure. Some dogs become asymptomatic carriers, meaning they show no symptoms at all but can still spread the disease to other pets and even people.  

Because leptospirosis is a zoonotic disease (meaning it can pass from animals to humans), protecting your dog also helps protect you and your family. All dogs who contract lepto are at risk of spreading the disease to humans. 

Why the Lepto Vaccine Matters 

Here’s the good news: lepto is preventable. The leptospirosis vaccine helps your dog’s immune system recognize and fight off the bacteria before it can cause serious illness. 

Both the American Animal Hospital Association (AAHA) and the American College of Veterinary Internal Medicine (ACVIM) classify leptospirosis as a core vaccine, making it just as necessary as the rabies vaccine. “Core” vaccines are considered essential for every dog, regardless of where they live or play, because the risk of exposure is widespread and the consequences are serious. 

If your pup enjoys visiting boarding facilities, dog parks, daycare, the groomer, or just exploring the great outdoors, they’re at a higher risk of encountering lepto. Even dogs living in urban areas can be exposed through puddles or shared potty areas where wildlife or other pets might pass through.  

Dr. O'Connor adds, “If your dog’s feet or nose touch the ground, they can be exposed to leptospirosis. Vaccination is the simplest and most effective way to protect them.” 

A Simple Step for Big Protection 

At Pet Paradise, our goal is to keep pets and their people safe. Leptospirosis cases continue to be reported across the country each year, and as more dogs enjoy social playtime, the potential for exposure grows. That’s why, beginning on August 1, 2026, we’re aligning with AAHA and ACVIM guidance to require all dogs to be fully vaccinated against leptospirosis. 

The leptospirosis vaccine is given as an initial two-part series (spaced 2–4 weeks apart), followed by an annual booster. Adverse reactions are exceptionally rare. 

Vaccination is one of the simplest ways to protect your dog from preventable diseases like leptospirosis. If you have questions about the vaccine or your dog’s vaccination schedule, speak with your veterinarian. 

For more information about why we’re giving our vaccine requirements a tune-up, click here.