Leptospirosis is a word many dog owners have heard—but may not realize just how serious it can be. This potentially life-threatening bacterial disease affects dogs of all breeds and lifestyles, and it can also be transmitted to humans, making it a public health concern as well as a veterinary one.

At Southcentral Veterinary Services, we’ve seen firsthand how dangerous leptospirosis can be—but the good news is, it’s largely preventable with vaccination and a little awareness.

What Is Leptospirosis?

Leptospirosis is caused by Leptospira bacteria, which are shed in the urine of infected animals. Dogs become infected when they come into contact with contaminated water, soil, or surfaces—often through drinking, swimming, walking through puddles, or licking their paws after exposure.

Once the bacteria enter the body (through mucous membranes or broken skin), they quickly spread through the bloodstream and target vital organs, especially the kidneys and liver.

How Dogs Get Leptospirosis

Lepto is especially common in warm, wet climates and during seasons of heavy rainfall or flooding. Risk factors include:

• Drinking or playing in standing water (puddles, ditches, ponds)

• Exposure to wildlife such as raccoons, skunks, opossums, deer, or rodents

• Living in or visiting rural, wooded, or farm areas

• Hiking, hunting, or camping with your dog

• Urban environments with rodent activity (yes, city dogs are at risk too!)

The bacteria can survive in the environment for weeks to months, especially in moist, shaded areas.

Symptoms of Leptospirosis in Dogs

Leptospirosis can be tricky to catch early—some dogs show mild or no symptoms, while others can become critically ill very quickly. Common signs include:

• Fever and lethargy

• Vomiting and diarrhea

• Loss of appetite

• Muscle pain or reluctance to move

• Increased thirst and urination (or decreased urination in advanced kidney damage)

• Jaundice (yellowing of the skin or eyes)

• Nosebleeds or other bleeding disorders

• Sudden collapse in severe cases

Because these symptoms can mimic other diseases, early diagnostics and testing are key.

Can Leptospirosis Be Treated?

Yes—if caught early, leptospirosis can often be treated with antibiotics and supportive care such as IV fluids, anti-nausea medications, and hospitalization. However, recovery can be lengthy, and dogs with severe organ damage may have lasting health issues or may not survive.

Some dogs may continue to shed the bacteria in their urine after treatment, which poses a risk to other animals and people.

Lepto Is Zoonotic—Here’s Why That Matters

Leptospirosis can infect humans, usually through direct contact with infected urine or contaminated surfaces. People can get sick by handling urine, bedding, or even shared water bowls—especially if they have open cuts or compromised immune systems.

Symptoms in people range from mild flu-like illness to kidney or liver failure, making it especially important to prevent exposure in the first place.

Prevention Starts With Vaccination

Fortunately, preventing leptospirosis is as simple as staying on top of your dog’s annual vaccinations.

About the Lepto Vaccine:

• The leptospirosis vaccine is safe, effective, and given annually.

• It protects against multiple strains of Leptospira (typically 4-serovar vaccines are used).

• It’s often included in combination vaccines (like DHPP-L), but not always—be sure to ask if your dog is protected.

• Puppies can receive their first lepto vaccine as early as 12 weeks, followed by a booster 3–4 weeks later.

Should My Dog Get the Lepto Vaccine?

If you’re wondering whether your dog needs the vaccine, here’s our advice:

• Outdoor access? Yes.

• Walks in neighborhoods with puddles or drainage areas? Yes.

• Exposure to wildlife or rodents? Yes.

• Live in the country or a wooded area? Absolutely.

• Travel to trails, lakes, or dog parks? Definitely.

• Even mostly indoor dogs may benefit, especially if rodents or standing water are around.

Basically, if your dog is on Earth and drinks water—they’re likely at risk.

Leptospirosis: Preventable, but Not to Be Ignored

Leptospirosis is a disease we hope you and your dog never have to deal with—but we’re here to act fast if you do. Prevention truly is the best medicine, and vaccination is your pet’s best protection.

Not sure if your dog is vaccinated against lepto? Let’s find out and update their protection if needed. Give us a call or schedule your pet’s wellness visit today—we’re always happy to help you stay a step ahead of illness.