Leptospirosis: A Risk to Pets and People
By Dr. Maria Krenz, DVM – ZimmVet
763-856-4848
Leptospirosis is a serious infectious disease that can affect dogs, other animals, and people. It is caused by spiral-shaped bacteria called Leptospira, which thrive in water and warm, wet soil. While leptospirosis has existed for many years, veterinarians are seeing an increase in cases across both rural and urban areas.
Because this disease can spread from animals to humans, prevention and awareness are very important.
How Pets Become Infected
Leptospirosis is spread through the urine of infected animals. The bacteria can survive in contaminated water or soil for weeks to months, especially in warm and moist environments.
Humans and animals can become infected through contact with:
- Contaminated water or soil
- Urine from infected animals
- Contaminated body fluids (excluding saliva)
The bacteria enter the body through the eyes, nose, mouth, or broken skin such as cuts or scratches. Drinking contaminated water can also cause infection.
Infected animals may continue shedding the bacteria into the environment for months or even years.
Pets are commonly exposed when they:
- Drink from puddles, ponds, or standing water
- Swim or walk through contaminated water
- Encounter infected wildlife such as raccoons, skunks, squirrels, opossums, or deer
As residential development expands into previously rural areas, pets are coming into closer contact with wildlife carriers of leptospirosis. Dogs can also spread the disease to other dogs and potentially to people.
Signs of Leptospirosis in Dogs
The signs of leptospirosis can vary greatly and are often nonspecific, meaning they can resemble many other illnesses. Some infected pets may not show symptoms at all.
Common signs include:
- Fever
- Vomiting
- Diarrhea
- Abdominal pain
- Loss of appetite
- Severe weakness or depression
- Muscle pain or stiffness
- Difficulty walking
- Dehydration
- Kidney or liver failure
Leptospirosis can also affect reproduction and may cause pregnancy loss or infertility.
Younger dogs, especially those under one year of age, tend to develop more severe disease. Studies show that 87–100% of infected dogs experience some degree of kidney dysfunction.
Treatment
Leptospirosis is typically treated with antibiotics, most commonly doxycycline. Many pets also require supportive care such as:
- Intravenous fluids
- Medications for nausea or pain
- Hospitalization
- Monitoring of kidney and liver function
Unfortunately, severe infections can cause permanent damage to the kidneys or liver, and some pets may not survive despite treatment.
Early diagnosis and treatment greatly improve the chances of recovery.
Prevention
Vaccination is one of the best ways to protect dogs from leptospirosis.
In 2022, the American Animal Hospital Association (AAHA) updated its guidelines to recommend leptospirosis vaccination for all dogs, regardless of lifestyle or geographic location.
Previously, hunting and farm dogs were considered most at risk. We now know that any dog spending time outdoors may be exposed, including dogs living in suburban and urban environments.
The vaccine:
- Protects against four major strains (serovars) of leptospirosis
- Is often included with routine distemper combination vaccines
- Requires annual boosters for continued protection
Currently, there is no approved leptospirosis vaccine for cats.
Why This Matters
Leptospirosis is becoming increasingly common in the Zimmerman area and throughout Minnesota. Because the disease can spread to people, protecting your dog also helps protect your family.
If your dog spends time outdoors—even briefly—it may be at risk.
Talk with your veterinarian about whether leptospirosis vaccination is appropriate for your pet.
Learn More
CDC Fact Sheet on Leptospirosis:
https://www.cdc.gov/leptospirosis/pets/index.html
Disclaimer:
This article is intended for educational purposes only and should not be considered medical advice. Always consult your veterinarian regarding your pet’s health and medical care.
