Leptospirosis in Dogs

Published Nov. 21, 2023
A dog drinks from a lake.

In This Article


What Is Leptospirosis in Dogs?

Leptospirosis is a disease that affects dogs and other mammals, including humans. It’s caused by a type of bacteria characterized as a spirochete, named for its spiral shape.

Dogs can become infected with leptospirosis in several ways, including contact with infected urine, urine-soaked soil or bedding material, water containing the bacteria, open wounds, bites, reproductive fluids, and even ingestion of infected tissues.

It can also be transmitted from mother dog to puppy through the placenta.

Leptospirosis is considered a medical emergency.

Once infected, the bacteria travel through the bloodstream, causing widespread inflammation and eventually settling in the kidneys and sometimes the liver or other organs, causing inflammation, pain, and ultimately organ failure.

From the kidneys, the bacteria are emptied into the environment through the urine.

Common carriers of leptospirosis include wildlife such as raccoons, skunks, opossums, and rats, as well as farm animals like cows and pigs.

Take extra precautions when traveling or living in rural areas. Additionally, leptospirosis is considered a zoonotic disease, meaning it can be transmitted from animals to humans.

If you suspect your dog may be infected, contact your veterinarian right away and avoid contact with your dog’s bodily fluids, especially urine.

Symptoms of Leptospirosis in Dogs

Once infected, dogs typically begin to develop symptoms within a week. These symptoms can vary from mild to severe, and some dogs may recover spontaneously. Common symptoms include:

Causes of Leptospirosis in Dogs

Leptospirosis is found throughout the United States and other countries, particularly in warm and wet climates.

The bacteria can survive for weeks to months and easily spread through water systems such as lakes, ponds, and streams, as well as in urine-contaminated soil.

Dogs who are young, unvaccinated, or have a compromised immune system are at higher risk, but the infection can affect dogs of any age, breed, and gender.

How Veterinarians Diagnose Leptospirosis in Dogs

Leptospirosis becomes a concern when a combination of your dog’s symptoms and results from blood work and urine testing suggest it.

Often, kidney and liver values will be affected. X-rays might be recommended, especially for dogs who are having respiratory problems.

Ultimately, the diagnosis of leptospirosis requires PCR testing (a test designed to find leptospirosis genetic material in a sample) of blood, urine, or both to detect the bacterial DNA, or MAT testing (a microscopic agglutination test) to measure a dog’s antibody level, or titer, against the disease.

The MAT test is typically repeated after several weeks to help determine the specific strain causing the infection. There is also an in-house test that serves as a useful screening tool but should be verified with either the PCR or MAT if it yields a positive result.

Be sure to provide information about any recent travel history, exposure to other dogs or wildlife, rural areas, or bodies of water frequented.

This information can raise suspicion for leptospirosis and alert the medical team to the possibility of an infectious zoonotic disease.

Treatment of Leptospirosis in Dogs

Dogs will initially need to be stabilized and treated at the veterinary hospital.

Supportive care measures, such as pain medications, antiemetics (to prevent vomiting), appetite stimulants, and liver supplements such as Denamarin or SAMe, may be recommended.

Fluid therapy, often supplemented with electrolytes, is necessary for treatment. IV fluids are important not only to combat dehydration but also to restore fluids lost due to vomiting and diarrhea. It also improves blood flow through a dog’s damaged kidneys.

At the hospital, antibiotics like penicillin G or ampicillin will often be given as an injectable.

Once symptoms are managed and the dog can eat on their own, they will be put on doxycycline, the preferred oral treatment, usually given twice a day for a few weeks.

It takes about a week of antibiotic therapy before your dog stops shedding bacteria in their urine. During this time, limit interactions with your dog to a minimum and take the necessary disinfection and protective measures to prevent transmission of leptospirosis.

In the hospital, your dog may have a catheter inserted to reduce the exposure risk for the veterinary team.

Renal replacement therapy, also known as dialysis, is another option that can certainly improve the prognosis, especially for dogs not producing sufficient urine despite appropriate therapy.

In some cases, only a few sessions may be needed.

While dialysis may not always be readily available and can at times be expensive, it’s an excellent therapeutic option that should be discussed with your vet.

In certain cases, humane euthanasia may be considered. These include dogs with severe kidney or liver failure, widespread hemorrhaging and an inability to clot, respiratory issues, or cases where treatment has failed to show improvement in symptoms.

Recovery and Management of Leptospirosis in Dogs

Depending on your dog’s response to therapy, they will likely be discharged after several days. Follow-up appointments will be scheduled in the following days and weeks to recheck blood work and ensure their kidneys (and other organs) are functioning appropriately.

Fortunately, prognosis for recovering pups is generally good.

However, in some cases, despite appropriate therapy, some dogs may continue to experience the lasting effects of leptospirosis, including kidney and liver issues.

Long-term medications and a specific diet may be necessary, along with ongoing follow-up appointments to monitor the progression of the disease.

Until you are instructed otherwise, make sure your dog urinates in an area that can be easily cleaned and disinfected, away from any water sources.

When caring for your dog at home, be sure to wear appropriate personal protective equipment (PPE). 

This includes face protection (goggles and mask), disposable gloves, and a disposable gown. Wear the PPE during interactions with your pup and especially when disinfecting urine-soaked areas or bathing hair that becomes soaked in urine. Properly clean and disinfect all bedding materials.

Leptospirosis is vulnerable to most household disinfectants and bleach. This disease has a limited survival rate in the environment, and is susceptible to UV irradiation and desiccation (the removal of moisture).

It’s important to note that dogs can become reinfected with leptospirosis in the future, so similar precautions should be taken even after recovery.

Prevention of Leptospirosis in Dogs

Preventing leptospirosis can be challenging due to the numerous bacterial strains involved. A vaccine, given in two injections three to four weeks apart and then annually, targets several of the main strains of leptospirosis.

While this vaccine significantly reduces the risk of your dog contracting the disease, it can’t completely prevent it. Additionally, vaccines can’t guarantee 100% immunity but can often lessen the severity if infection occurs.

The vaccines contain various strains, some more than others, so be sure to discuss the most suitable vaccine with your veterinarian.

Further recommendations include avoiding potential sources of contamination, such as limiting access to standing water, avoiding contact with wildlife, using pest control when necessary, and preventing access to garbage.

Leptospirosis is a transmissible and zoonotic disease, which means other dogs and people can become infected. During treatment, don’t allow your dog to interact with others and make sure you use the proper PPE when interacting with your dog.

Frequent hand washing and good overall hygiene is necessary. Avoid allowing your dog to encounter any open wounds or share bodily fluids.

Leptospirosis in Dogs FAQs

How likely is a dog to get leptospirosis?

Leptospirosis is found worldwide, so the risk of dogs becoming infected is quite high.

With the advances in transportation, increased travel, relocation of people with their pets, the relocation of pets through shelter groups, and the occurrence of natural disasters such as flooding and hurricanes, the prevalence of leptospirosis has increased.

Can you treat leptospirosis in dogs at home?

No. Leptospirosis is an extremely debilitating disease, but survival rates are high with appropriate therapy. Treatment requires antibiotics and fluids at a veterinary hospital.

Featured Image: AvGusT174/iStock / Getty Images Plus via Getty Images

Michael Kearley, DVM


Michael Kearley, DVM


Dr. Michael Kearley graduated from the University of Florida College of Veterinary Medicine in 2013. He graduated with a certificate in...

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