What Is Leptospirosis?
Leptospirosis is an infection caused by bacteria that is found in soil and water. Leptospirosis is seen across North America and can be very serious, even fatal, if not diagnosed and treated quickly. In addition to dogs, other animals such as livestock, wildlife, and rodents, can be affected.
It is a zoonotic disease, which means that it can be passed from animals to people. Most humans in the United States are infected from waterways during activities like swimming or from infected rodents.1
Even though the American Animal Hospital Association recommends vaccination against leptospirosis in some dogs depending on their lifestyle, the American College of Veterinary Internal Medicine believes all dogs should be vaccinated against leptospirosis, regardless of age, breed, or lifestyle.2
How Does Leptospirosis Affect My Dog?
Leptospirosis, also known as "lepto", is a bacterial infection that is caused by a family of bacteria called Leptospira. The bacteria are often found in standing water and damp, muddy areas. More cases are seen in the wetter parts of the year, typically late summer and fall, particularly after heavy rainfall. Infected animals such as rodents and livestock pass the bacteria into the environment in their urine, and then animals or people become infected when they come into contact with water contaminated with the bacteria.
In the US, around 100-150 cases of leptospirosis are reported in people each year.3 As many as a third of dogs in the US will test positive for antibodies against leptospirosis, which means that they have been exposed to the disease.4
Signs of Leptospirosis in Dogs
Lepto has historically been characterized as a disease in large breed dogs, but this is no longer the case. Any dog living in any area is now at risk of leptospirosis.
Not all dogs that are exposed to leptospirosis become visibly ill, but if they do become sick, then their symptoms tend to start around 4-12 days after being exposed to the bacteria. Leptospirosis tends to be most severe in young (less than 6 months) and unvaccinated dogs.
Signs of Leptospirosis
Signs of leptospirosis can vary, but may include:
- • Lethargy
- • Poor appetite
- • High temperature
- • Vomiting
- • Diarrhea
- • Increased thirst
- • Increased urination
- • Jaundice (yellow color to the normal pink areas inside the mouth and around the eyes)
Leptospirosis can cause significant damage to the kidneys and the liver, which is why some of the signs listed above may be seen. It’s therefore a serious disease that must be diagnosed and treated early to help ensure that organ damage is minimized.
With early treatment, the chances that a dog with leptospirosis will recover are good. If left untreated, many dogs will die from kidney or liver failure. Unfortunately, even with prompt treatment, some dogs may still suffer permanent damage to their liver or kidneys.
Leptospirosis is therefore a disease that is best prevented. And thankfully, there’s a lot that can be done to help prevent leptospirosis in dogs.
Vaccines for Leptospirosis
Vaccines for leptospirosis play a critical role in helping protect dogs from leptospirosis. Vaccination is started with a 2-vaccine course, followed by annual vaccination.
Historically, there was some concern about adverse reactions to vaccines for leptospirosis; however, improvements in vaccine manufacturing processes and studies quantifying vaccine reaction rates show that leptospirosis vaccines are as safe as other vaccines available for dogs.3
There are a number of different Leptospira bacteria that cause leptospirosis. Vaccines that protect against 4 different strains of Leptospira bacteria (called quadrivalent vaccines) are recommended.2
In addition to vaccination, there are other steps that you can take to help keep your family and your dog safe from leptospirosis:
- Don’t let your dog drink from or swim in rivers, lakes, ponds, or stagnant water
- Keep your dog away from wildlife or rodents
- Don’t allow rodent populations to proliferate
Transmission to Humans
Leptospirosis is a zoonotic disease, which means that it can be transmitted to humans from other animals. Leptospirosis transmission occurs when a person’s eyes, mouth, or an open wound comes into contact with the bacteria. It is possible for a person to become infected with leptospirosis from their dog. However, in the US most cases of leptospirosis are transmitted during water activities or from exposure to rodents.1
Minimize Risk of Transmission
To help minimize the risk of leptospirosis transmission, wear gloves when cleaning up urine, wash hands regularly, and prevent dogs from licking your face.
Because leptospirosis affects a wide variety of animals as well as people, effective control of leptospirosis requires a collaborative approach from medical professionals, veterinarians, and national surveillance organizations.
In the US, leptospirosis is a nationally notifiable disease, which means that cases must be reported to the Centers for Disease Control and Prevention.
Key Takeaways
Leptospirosis is a serious disease caused by a family of Leptospira bacteria.
Leptospirosis is a zoonotic disease, which means that it can be passed from animal to person.
Prevention of leptospirosis is key, and vaccination is a critical step in helping protect dogs and preventing the spread of leptospirosis.
Successful control of leptospirosis involves a collaborative effort from pet owners, veterinarians, medical professionals, and national surveillance organizations.
