Dog splashing in river

Leptospirosis in Dogs


You’ve likely had a discussion with your veterinarian regarding whether or not to vaccinate your dog against Leptospirosis, often simply referred to as Lepto.  As dogs have different lifestyles and Lepto is not found everywhere, the discussion about vaccination is important in order to access the risks of exposure versus potentially vaccinating unnecessarily. Your veterinarian will be very familiar with the risks in your area and is the best person to have this discussion with.

What is Leptospirosis and how are dogs exposed to it?

Leptospirosis is a bacterium that is carried by wildlife such as raccoons, skunks and rats. The most common form of transmission to your dog is through exposure to the urine of a wildlife host.

It could be as simple as…

A racoon urinates in the grass of your local park.

You and your dog go for an early morning walk while morning dew is still on the grass.

Your dog walks through the area of grass that was recently urinated on by the racoon.

Once home, your dog licks his feet to clean himself up and ingests remnants of the urine mixed with the dew.

Your dog has now been exposed to Lepto. Exposure such as this is almost completely unavoidable. Unless a dog lives mostly inside, the possibility of exposure always exists.

The risks of contracting Leptospirosis

Although Leptospirosis has been found in most of the Canadian provinces, it is not common in all areas. As a result, the relative risks of exposure will vary geographically and with the lifestyle of you and your pet. Dogs who splash through ravines are more likely to be exposed to the bacteria than dogs that never leave the sidewalk. That being said, it is worth noting that even if your dog is exposed, it doesn’t necessarily mean he will develop the disease. Some studies have shown that as many as 30% of unvaccinated dogs have been exposed to Leptospirosis at some point in their lives. One has to consider that the protective immune system varies between dogs (even without taking vaccinations into account) and young, old or immune-compromised dogs are less likely to be able to eliminate the disease on their own should exposure occur.

Signs your dog may have been exposed to Leptospirosis

The Lepto bacteria will penetrate through cuts and scrapes in the skin and can be ingested orally by any dog. Once inside the bloodstream, the bacteria can travel virtually anywhere in the body so clinical signs can vary widely. Typically, as with any infection, your dog will have a fever with general malaise. Within a couple of days, this will progress to signs of a stiff gait, poor appetite, gastrointestinal symptoms, and often excessive drinking and urinating. These signs come on quickly and treatment needs to be aggressive and prompt.

Treatment for dogs with Leptospirosis

Although many of the clinical signs are non-specific for Leptospirosis, a thorough physical exam, history (including vaccine history), blood tests and a urinalysis will usually deliver a quick diagnosis. Treatment will require hospitalization on intravenous fluids, antibiotics to target the Leptospira bacteria and additional drugs to deal with the other symptoms (e.g. vomiting). If treated promptly, the prognosis when contracting Leptospirosis is quite good. However, if clinical signs are ignored until the dog is really ill, the pet is likely to suffer from chronic organ failure or worse.  

If your dog has a definitive diagnosis of Leptospirosis and is ultimately discharged from the hospital for continuing home care, it is very important to appreciate that it is a zoonotic disease meaning it can be transferred from pets to people. It is very important to discuss its zoonotic potential with your veterinarian. Through diligent use of disinfectants, the wearing of latex gloves, kennel confinement and isolation, you will be most effective in preventing transmission to the other four and two-footed family members in your home.

To vaccinate or not to vaccinate against Leptospirosis?

In areas where Leptospirosis is a problem, preventing exposure is virtually impossible. The only effective prevention is through vaccination. The vaccine does work well, but there is the possibility of short term side effects from the vaccine itself, especially with small dogs. If the area where you live is endemic for this nasty disease, discuss the pros and cons of vaccination with your veterinarian.