Could My Dog Have Leptospirosis?

If your dog has been splashing through puddles, wading in a pond, or sniffing around areas where wildlife roam, leptospirosis is worth knowing about. It’s a bacterial infection that can hit fast and hit hard, sometimes causing serious kidney or liver damage before you even realize something is wrong. The good news: it’s treatable, it’s largely preventable, and knowing what to look for makes a real difference.

What is leptospirosis in dogs?

Leptospirosis (often called “lepto”) is a bacterial infection caused by a type of bacteria called Leptospira. These bacteria live in soil and water all over the world and can survive for weeks or months in warm, wet environments. That pond your dog loves, the puddle at the trailhead, the muddy patch in the backyard where a raccoon walked through last night, any of these could be a source.

There are more than 300 known strains of Leptospira, which is part of what makes this infection tricky. Cases are most common in the midwestern, eastern, and southwestern United States, but lepto has been reported across the country and around the world, with different strains being more prevalent in different regions.

One important thing to know upfront: this is a zoonotic disease, meaning it can spread from animals to humans. That doesn’t mean you should panic, but it does mean there are some precautions worth taking if your dog gets sick.

How do dogs get leptospirosis?

After exposure, symptoms usually show up within about a week, though the window can range from a few days to two weeks. The most common routes of exposure are:

• Drinking from or swimming in contaminated water, including ponds, puddles, lakes, rivers, or stagnant water that’s been sitting in contact with soil or wildlife
• Direct contact with urine from an infected animal
• Walking through contaminated soil or mud, especially if your dog has any small cuts on their paws
• Contact with infected bedding, food, or water bowls

The biggest carriers of Leptospira bacteria are wildlife, specifically rats, raccoons, skunks, and opossums. Infected dogs can also spread it to other dogs. Because rats in particular shed the bacteria in their urine, urban dogs aren’t automatically safer than rural ones. A city dog walking through a alley where rats have been can be just as exposed as a farm dog roaming fields.

After exposure, symptoms usually appear within about a week, though the window can range from two to fourteen days.

Leptospirosis symptoms in dogs

Here’s the tricky part: lepto doesn’t always look the same. Some dogs get mildly ill and recover without anyone realizing what it was. Others develop a severe, fast-moving illness that affects the kidneys and liver. And in some cases, dogs show no obvious signs at all while the bacteria quietly damages their organs.

• Lethargy or unusual tiredness: Your dog just doesn’t want to get up or seems more tired than usual. On its own, this could mean almost anything. Pay attention to what else is going on alongside it.
• Loss of appetite: Skipping a meal isn’t automatically a red flag, but take it seriously if it’s paired with any other signs on this list.
• Fever: Your dog feels hot to the touch or seems uncomfortable and restless. A rectal temperature above 102.5°F is a fever in dogs. Fever plus any other symptom on this list warrants a same – day vet call.
• Vomiting or diarrhea: Common with many illnesses. On its own, not necessarily urgent. Combined with fever, lethargy, or the signs below – call your vet.
• Muscle pain or stiffness: You might notice your dog moving slowly, reluctant to climb stairs, or flinching when touched. This is a more specific signal that something systemic is happening.
• Increased thirst and urination, or the opposite: Changes in how much your dog is drinking and urinating are a particularly important signal with lepto. If your dog is suddenly going much more or much less than usual, that’s a same-day vet call, not a wait-and-see situation. This can indicate the kidneys are already being affected.
• Yellowing of the eyes or gums (jaundice): Yellowing of the whites of the eyes or the gums signals liver involvement. This is a serious sign. Don’t wait for a regular appointment.
• Swollen legs or fluid buildup: A sign of more advanced illness affecting organ function.
• Blood in urine or unexpected bruising: Signs of bleeding complications in severe cases.

Should I go to the emergency vet, or can this wait?

Call your vet and aim to be seen today if:

• Your dog has a fever alongside vomiting, lethargy, or muscle stiffness
• Urination has changed significantly — much more or much less than normal
• Your dog was exposed to contaminated water or wildlife in the past two weeks and is now showing any symptoms

Go to emergency care now if:

• Eyes or gums are yellowing
• Your dog has stopped urinating or is producing very little urine
• Your dog has collapsed or is too weak to stand
• You’re seeing blood in the urine or unexplained bruising
• Symptoms are progressing rapidly over a few hours

Time matters enormously with lepto. Organ damage can develop and worsen quickly. If you’re unsure, call your vet or an emergency line and describe what you’re seeing, don’t wait until morning.

How is leptospirosis diagnosed?

There’s no single instant test for lepto, so your vet will likely use a combination of approaches to piece together the picture. Here’s what to expect:

Blood work and urinalysis

Your vet will start with standard blood tests and a urine sample to assess how the kidneys and liver are functioning. Elevated kidney or liver values alongside the right symptoms raise an immediate red flag.

PCR test 

A PCR test (polymerase chain reaction) looks for Leptospira DNA directly in a blood or urine sample, scanning for the bacteria’s actual genetic material rather than waiting for the body to produce antibodies. It’s most useful early in the infection, before antibody levels have had time to rise.

MAT (Microscopic Agglutination Test) 

A blood test that looks for antibodies and can suggest which group of bacteria your dog was exposed to. Early in the infection, antibody levels may not be detectable yet, so your vet may recommend paired testing — an initial sample and a follow-up sample one to two weeks later — to compare results. It’s worth knowing that prior vaccination can affect how MAT results are interpreted, which is something your vet will factor in.

Chest X-rays 

If your dog is showing respiratory signs like coughing or labored breathing, your vet may check for fluid or hemorrhage in the lungs, which can occur in more severe cases.

Treatment options

Lepto responds to antibiotics, and the earlier treatment starts, the better the outcome.

Antibiotics 

Doxycycline is the primary antibiotic used. It works in two phases: first clearing the bacteria from the bloodstream during the acute illness, then a continued course to eliminate the bacteria from the kidneys, where Leptospira can linger and continue to shed in urine. If your dog can’t tolerate doxycycline, your vet may start with a penicillin-based antibiotic, then transition to doxycycline to complete the treatment.

Hospitalization and supportive care 

Many dogs with lepto need to be hospitalized, sometimes for several days. This typically involves IV fluids to support kidney function, medications to manage vomiting, and close monitoring of kidney and liver values. If kidney failure is severe, dialysis may be needed at a specialty facility, though this is less common.

What recovery looks like 

Many dogs recover fully with early, aggressive treatment. It’s important to be honest here though: even with prompt care, survival to hospital discharge runs at around 80% – meaning roughly 1 in 5 dogs with confirmed leptospirosis doesn’t make it, even with treatment. For dogs that develop pulmonary hemorrhage syndrome (bleeding into the lungs), survival rates are lower still, around 40 to 50%. Some dogs who survive are left with long-term kidney or liver disease requiring ongoing management. Your vet will check bloodwork after treatment to assess how well the organs have recovered.

Can leptospirosis spread to humans?

Yes. Leptospirosis is a zoonotic disease, meaning it can pass from animals to people. Humans most commonly pick it up through contact with the urine of an infected animal, including an infected dog.

If your dog has been diagnosed with lepto or you’re waiting on test results:

• Wear disposable gloves when handling your dog or cleaning up their urine
• Wash your hands thoroughly after any contact
• Avoid letting your dog lick open cuts or your face
• Contact your own doctor and let them know about the potential exposure, especially if you develop flu-like symptoms (fever, muscle aches, headache) in the weeks following your dog’s illness

Most healthy adults exposed to lepto won’t develop serious illness, but people who are immunocompromised, elderly, or pregnant should be especially cautious and speak to a doctor quickly.

Prevention

The single most effective thing you can do is vaccinate your dog. But prevention doesn’t stop there.

The leptospirosis vaccine

The single most effective prevention step is vaccination. The lepto vaccine is recommended annually for most at-risk dogs and covers the four most common Leptospira strains known to cause illness in dogs. It won’t protect against every strain — given that more than 300 exist — but it dramatically reduces the risk of the most dangerous infections, and immunity lasts at least 12 months with annual boosters.

Lepto vaccination is considered a “lifestyle vaccine” by many vets, meaning it’s recommended based on risk factors rather than being universally required. Given how widespread exposure can be — even in cities — many vets recommend it for virtually all dogs. Talk to your vet about whether your dog’s lifestyle and location put them at elevated risk.

Environmental precautions

• Avoid letting your dog drink from ponds, puddles, or stagnant water where wildlife is active
• Reduce rodent access around your home: secure trash, remove food sources, and address any rat or mouse populations
• Keep food and water bowls clean and indoors where possible
• Be extra careful in the days after heavy rain, when contaminated runoff can spread bacteria into areas your dog normally uses

Does pet insurance cover leptospirosis?

Lepto treatment is expensive. Hospitalization, IV fluids, bloodwork, and antibiotics can run into the thousands – more if specialty care is needed.

Lemonade pet insurance can cover eligible treatment costs, including diagnostics, hospitalization, and prescription medications, as long as the condition develops after your policy is active and outside the 14-day illness waiting period.

One important caveat: because lepto is vaccine-preventable, coverage can depend on vaccination history. If your vet recommended the lepto vaccine and you declined it, a resulting claim may not be covered. Coverage applies if your dog was vaccinated, if the vaccine wasn’t recommended, or if your dog was vaccinated and contracted it anyway.

If lepto is a real risk in your area, get a policy in place before something happens, not after.

Before we go

Leptospirosis is one of those conditions that can feel overwhelming when you first read about it, but it’s also one where preparation genuinely matters. Annual vaccination, smart habits around water and wildlife, and knowing the symptoms to watch for puts you in a much stronger position than most dog owners. And if your dog does get sick, catching it early gives them the best shot at a full recovery.

If you’re not sure whether your dog is up to date on the lepto vaccine or whether pet insurance makes sense for your situation, your vet is the right first call. And if you’re curious about what Lemonade covers, you can get a quote in as little as 90 seconds, to see what a plan could look like for your dog.

A few quick words, because we <3 our lawyers: This post is general in nature, and any statement in it doesn’t alter the terms, conditions, exclusions, or limitations of the policies issued, which differ according to your state of residence. You’re encouraged to discuss your specific circumstances with your own professional advisors. The purpose of this post is merely to provide you with info and insights you can use to make such discussions more productive! Naturally, all comments by, or references to, third parties represent their own views, and Lemonade assumes no responsibility for them. Coverage may not be available in all states. Please note that statements about coverages, policy management, claims processes, Giveback, and customer support apply to policies underwritten by Lemonade Insurance Company or Metromile Insurance Company, a Lemonade company, sold by Lemonade Insurance Agency, LLC.  The statements do not apply to policies underwritten by other carriers.