Category Archives: Pet Disease

What Is Leptospirosis?

What Is Leptospirosis?

Leptospirosis (Lepto) is a bacterial infection that occurs in mammals like rats, raccoons, skunks, horses, cows, pigs, dogs and humans.

Symptoms of Lepto

Lepto tends to attack the liver and kidneys. As a result, symptoms are usually associated with liver and / or kidney problems. Symptoms include:

  • Nothing
  • Fever
  • Vomiting
  • Dehydration
  • Lethargy
  • Lack of appetite
  • Increased drinking
  • Increased urinating
  • Icterus (yellow skin and eyes)
  • Pain (especially muscle and kidney)


Lepto is typically transmitted via the urine of an infected animal. When another animal comes into contact with the Lepto bacteria from the infected urine, the Lepto bacteria can infect that animal through the mouth (if they are drinking), or through cuts on the skin. Lepto bacteria are very hardy and can live for a long time in wet environments that an infected animal has urinated in.

Since Lepto likes wet (but not freezing) environments, Lepto is most common in the spring and fall.


Dogs that drink from stagnant water, especially in wooded areas where wildlife is abundant, are particularly at risk. However, dogs that live in densely populated cities are also at risk due to the concentration of urban wildlife (racoons and skunks).

Human Health

Since Lepto, like rabies, is zoonotic (infected dogs may infect people), it is an especially important disease to consider vaccinating against.

Transmission to humans can occur when urine or blood from an infected dog contacts a person’s skin or mucous membranes (eyes, mouth, or nose). For this reason, Lepto can be a serious health risk for both your pet and your family.


Fortunately, there is a vaccine to help decrease the risk associated Lepto. It is particularly important for dogs at increased exposure risk.

Types of Lepto

There are a number of different serovars (types) of Leptospira bacteria in nature. Each serovar is unique and must be vaccinated for specifically. Most serovars pose little risk to pets, but recently some newer serovars have emerged as a serious health concern to both dogs and people in Ontario.

Lepto Has Re-Emerged

With a decrease in natural habitat, raccoons and skunks are adapting to life within our cities and urban areas, leading to a larger number of encounters with our pets. This increase in exposure to the main reservoir hosts for newer types of Lepto has lead to a re-emergence of the disease.

Older Vaccines May Not Be Effective

These new serovars are not those for which vaccines have traditionally been available in years past. As a result, using older vaccines may offer less protection for your pet than newer vaccines.

Lepto Vaccination Today

A vaccine, which has now been available in Canada for six years has been designed to protect against most of these newer types of Lepto. It vaccinates for the 4 most common types of Leptospira bacteria, and is the best prevention we have for this disease.

When to Vaccinate

Late summer and early fall are the best times to vaccinate your dog against this bacteria, since this season usually brings the optimum conditions for the occurrence and persistence of Lepto in the environment. Please understand that our decision to recommend vaccination of your dog against Leptospirosis has only come following consultation with independent veterinary specialists who are experts in the area of infectious diseases.

Yearly Boosters

Unfortunately, since Lepto vaccines are designed to protect from a bacterial infection, residual immunity only lasts for one year. Please note that this is different than vaccines that are designed to prevent viral infections which have longer durations of immunity. If you require more information please contact us.