Leptospirosis in Dogs: How Concerned Should You Be?

Cases of leptospirosis in dogs (and humans) have been on the rise in recent years. Here are the facts you need to know, from a veterinarian.

By: SFB579
Cases of lepto in dogs are on the rise. By: SFB579

Leptospirosis in dogs is a serious disease not only affecting dogs, but also farm animals, wild animals, rodents and humans.

What is Leptospirosis Vaccine for Dogs?

Years ago, many veterinarians included lepto protection in their routine canine vaccine. Then, many veterinarians stopped vaccinating for lepto in dogs because the disease was thought to be extremely rare, and the inclusion of lepto in the “6-in-1” vaccine was blamed for a higher incidence of vaccine reactions.

Many of us stopped vaccinating for lepto because we wanted to reduce vaccine reactions, and the risk of contracting lepto was believed to be very low. Cases of leptospirosis are on the rise in the past several years in many areas of the United States, and it can be fatal to our pups if not diagnosed early and treated aggressively.

There is a newer leptospirosis vaccine on the market that is safe and covers more strains of lepto than the older vaccine. This lepto vaccine is well tolerated and does not seem to cause significant or above average vaccine reactions. My personal view is to give this vaccine separately to dogs who are at risk.

What Is Leptospirosis in Dogs?

Leptospirosis is a bacteria spread through the urine or fluids of infected animals.

Infected urine from, say, a raccoon, can seep into water or soil and survive there for months. An animal (and rarely human) can come into contact with the infected urine, water source or soil and become infected. Your dog could drink infected water, or the bacteria could enter through contact with eyes, nose, mouth or broken skin.

How Concerned Should I Be?

The prevalence of leptospirosis and risk to your dog vary greatly. The first thing to do is check with your veterinarian.

Ask these questions:

  1. Is my dog already vaccinated for lepto?
  2. Is there a risk of lepto in my area?
  3. Do you think my dog should be vaccinated?

Which Dogs Are at Risk?

If you are in an area where leptospirosis is in the rodent or wild animal population, all dogs are at risk. The fact that your dog does not go swimming or drink from streams does not ensure your little couch potato will not be exposed to lepto.

An infected animal or rodent can urinate anywhere, and your dog can come in contact with the bacteria. Lepto has been found in rural, suburban and urban areas. Naturally, if your dog walks on a leash most of the time and does not have contact with standing water or soil, there is very little risk.

In this video, Dr. Emily Pointer of the ASPCA talks about susceptibility and symptoms of leptospirosis:

YouTube player

What Are the Symptoms of Leptospirosis in Dogs?

Although the signs and symptoms of lepto are varied, the vast majority of dogs present with fever, lethargy and often acute kidney damage. Vomiting, diarrhea, abdominal pain, refusal to eat, lethargy, thirst, etc. may all be present.

The most common presentation for lepto is a young to middle-aged dog who becomes acutely ill and is running a fever. If initial blood tests reveal elevated kidney or liver values, lepto should be on the list of possible causes.

How to Diagnose Leptospirosis in Dogs

There is a specific blood test that tests for exposure to multiple strains of leptospirosis. If your vet is highly suspicious that leptospirosis may be the cause of your dog’s sudden illness, treatment with antibiotics can be started while the blood test is pending.

If your dog is in kidney failure, your veterinarian will suggest your dog be hospitalized and be supported with intravenous fluids and any other supportive care indicated.


Early detection, treatment and the age and overall condition of your furry friend play a big part in predicting outcome.

If a young to middle-aged dog (most commonly affected age group) becomes acutely ill and gets quick antibiotic therapy and fluid support, the outcome should be favorable.

As with any infection, prognosis depends on how much damage the infection has done. In cases of lepto, the kidneys and the liver can be damaged, but that damage can be reversed with early treatment.

Jake Was in the Lake: An Example of Leptospirosis in Dogs

In my 2 most recent leptospirosis cases, both Labrador and Aussie patients survived and have no lasting damage, thank goodness.

I owe the Aussie’s early detection in great part to my highly observant technicians. When Jake, the 5-year-old Aussie, came into my office and his human said he was just a little “off,” I was unaware of how sick he was.

My technician then took Jake out for a quick walk. The technician told me Jake had lifted his leg and urinated for what seemed to be an eternity. He was also running a slight fever. Jake’s family had not noticed that he’d been drinking abnormal amounts of water.

Quick blood tests revealed Jake was in kidney failure. While the lepto tests were in process, we got Jake on IV fluids and began antibiotics, and he began to feel better within 24 hours.

Sure enough, just watching Jake urinate an unusual amount of urine was the biggest key to a quick diagnosis in our un-neutered, urine-sniffing, pond-swimming patient (all big risk factors for leptospirosis). Speaking of urine, let me end by informing, but not alarming you, of what to do if lepto is suspected or diagnosed in your own dog.

Can I Catch Leptospirosis From My Dog?

Yes, leptospirosis is a zoonotic disease, meaning it can be transmitted from animals to people. Avoiding contact with infected urine, stepped-up hygiene and cleanliness and common sense is usually enough to ensure your safety.

When your dog comes home from the hospital and is completing the entire course of antibiotics prescribed for a lepto infection, do these things:

  1. Wash hands thoroughly after handling bedding and bowls.
  2. Stop with the face licking for now.
  3. Wear gloves and use bleach or other disinfectants when cleaning up urine accidents in the house.
  4. As with all zoonotic diseases, limit contact between your pet and any pregnant or immunosuppressed persons until the antibiotics are finished. Consult your physician with any and all specific questions.
  5. The lepto organism is killed by sunlight and/or freezing temps and is not usually a worry in your backyard. During acute infection, walk your dog on a leash in a designated quarantine area. Clean areas thoroughly while he is taking antibiotics.

Bottom Line on Leptospirosis in Dogs

  • The disease is rare but present in certain areas. Check with your veterinarian for information.
  • All dogs in areas where lepto is a problem are susceptible. This used to be considered a disease of rural hunting dogs, but that is not true any more.
  • Lepto is treatable, and the prognosis is good if caught early.
  • Can leptospirosis in dogs transfer to humans? Lepto can be spread to humans but not easily. Infected urine is the biggest worry, and proper hygiene should protect you.
  • Talk with your veterinarian about the pros and cons of vaccinating your dog.

I have shared this article now because lepto is most prevalent in late summer and fall. Nobody should be overly alarmed about leptospirosis, but being knowledgeable is a good thing!

Frequently Asked Questions (FAQ)

How common is leptospirosis in dogs?

Leptospirosis is relatively common in dogs, particularly in certain regions or environments where the bacteria are prevalent. Regions with frequent vaccination will often see cases of leptospirosis less commonly.

What causes leptospirosis in dogs?

Leptospirosis in dogs is caused by a bacteria called Leptospira. These bacteria are typically found in the urine of infected animals and can live in soil and water, causing contamination of the environment. Dogs can become infected by coming into contact with contaminated water, soil, or other animals that possess the bacteria.

Is leptospirosis contagious in dogs? 

Leptospirosis can be contagious among dogs. It can spread through contact with infected urine, saliva, or other bodily fluids of infected animals. So, if you’re wondering, “How is leptospirosis transmitted in dogs”, it can also be spread to people, so avoiding contact is helpful. 


This pet health content was written by a veterinarian.