What to know
- Leptospirosis can affect animals, who can then spread it to people.
- Leptospirosis has a range of symptoms in animals from mild disease to organ failure or death.
- Treatment usually helps animals get better, but organ damage caused by leptospirosis can be permanent.
- Some animals can be vaccinated to prevent infection.

Animals can spread leptospirosis to other animals and people
Leptospirosis is a disease that can affect people and animals, including pets and farm animals, rodents, and wild animals like wild pigs and marine mammals. The bacteria that cause leptospirosis are spread through the urine (pee) of infected animals. The bacteria can contaminate water or soil, where it can survive for weeks to months.
Just like people, animals can get leptospirosis through contact with contaminated urine or body fluids of an infected animal or contact with contaminated water or soil. Leptospirosis signs and symptoms in animals can vary widely, and some animals don't show symptoms at all.
How animals get leptospirosis
Animals may get leptospirosis through:
- Direct contact with infected urine (pee) or contaminated water sources, especially drinking from slow-moving or stagnant water sources, like ponds, rivers, lakes, or streams
- Bite wounds or skin damage from other animals, including rodents or farm animals
- Eating infected body tissues or organs
- Being born to an infected mother
Farm animals may also get leptospirosis from breeding with infected animals.
Dogs
Almost every dog is at risk of leptospirosis, whether they live in the country, suburbs, or city. Dogs can be at higher risk if they roam where they may be exposed to infected wildlife or farm animals, or contaminated water sources. They are also at higher risk if they have contact with other dogs at dog parks or boarding or training facilities.
A vaccine to prevent leptospirosis in dogs is available in the United States.
At first, dogs may have the following symptoms:
- Fever
- Depression
- Lethargy (not moving much)
- Loss of appetite
- Joint or muscle pain
- Eye and nasal discharge
- Changes in how much they pee
- Jaundice (yellowing of the eyes and skin)
Within a few days, dogs infected with leptospirosis may start throwing up, be dehydrated, and have back pain from kidney failure.
Cats
Cats can become infected with leptospirosis, but compared to other animals, they are considered resistant because they rarely show symptoms. Infected cats may shed leptospirosis in their urine for years.
A vaccine to prevent leptospirosis in cats is available in the United States.
Cows
Leptospirosis in cows is a well-recognized disease that affects their reproductive system. It shows up in two ways:
- Chronic infection (also called silent infection) is more common.
- Acute infection is not as common, and it's usually seen as an outbreak,
Goats and sheep
Sheep can become infected with leptospirosis, but because they rarely show symptoms, sheep are considered resistant to the disease when compared to cows and pigs. Goats with leptospirosis do show symptoms, but there is less available information about leptospirosis in goats.
There is a vaccine available to control leptospirosis in cows, goats, and sheep. Antimicrobials can help treat animals that have been diagnosed with the disease. Good animal management practices can help prevent and reduce the spread of leptospirosis.
Horses
Leptospirosis is common in horses in the United States.
There is a vaccine that helps avoid severe infection in horses. You can help prevent and reduce the spread of leptospirosis through good management practices.
Domestic pigs and wild pigs (feral swine)
Leptospirosis is a common disease of pigs and feral swine throughout the world. It can be a major cause of reproductive loss, including abortions, stillbirths, or weak piglets.
Hunters and other people who may come in contact with infected feral swine might get leptospirosis. Feral swine may also spread leptospirosis to pets, farm animals, and other wildlife.
Vaccination can help avoid infection in pigs. You can help prevent and reduce the spread of leptospirosis through good livestock management practices.
Marine mammals
Leptospira, the bacterium that causes leptospirosis, was first found in 1970 in California sea lions along the coast of California, Oregon, and Washington. Since the 1980s, there have been yearly seasonal outbreaks in the sea lions, with severe outbreaks every 4-5 years.
Other marine mammals that can be infected with leptospirosis include the northern fur seal, elephant seal, and Pacific harbor seal.
Symptoms in animals
Type of animal
Signs and symptoms
Dogs
- Fever
- Depression
- Lethargy (not moving much)
- Loss of appetite
- Joint or muscle pain
- Eye and nasal discharge
- Changes in how much they pee
- Jaundice (yellowing of the eyes and skin)
- Vomiting, dehydration, back pain from kidney failure
Cats
Rarely show symptoms
Horses
- Fever
- Eye infection that keeps coming back (uveitis)
- Abortion (pregnancy loss in animals)
- Acute kidney failure
Cows, goats, and sheep
- Abortion
- Stillbirth
- Birth of weak offspring
- Infertility
- Milk that is slightly red from blood
- Going back into heat after already being pregnant (in cows)
Pigs and feral swine
- Fever
- Abortion
- Stillbirth
- Birth of weak or sick piglets
- Jaundice
- Acute kidney failure
- Loss of appetite
Marine Mammals
- Increased drinking and peeing
- Depression
- Don't want to use hind flippers
- Acute kidney failure
- Vomiting

Treatment in animals
If you think an animal may have leptospirosis, contact a veterinarian immediately. The veterinarian can perform tests to see whether or not the animal has the disease and start treatment as soon as possible.
If an animal is treated early with antibiotics, it may recover faster, and it can help prevent severe organ damage. It may also need other treatment methods, such as dialysis and fluids.
Prevention in animals
Rodent control
To help prevent leptospirosis infection in animals, keep rodent problems (rats, mice, or other animal pests) under control. Rodents can carry and spread the bacteria that cause leptospirosis.
Vaccination
In the United States, you can get dogs, cats, cows, sheep, goats, pigs, and horses vaccinated against leptospirosis. The vaccine doesn't provide 100% protection because there are many strains of the bacteria that cause leptospirosis, and the vaccine doesn't provide immunity against all strains. Get animals vaccinated even if they get leptospirosis because the vaccine might cover different strains, and it may help avoid more severe disease.
Livestock management practices
In farm animals, preventing leptospirosis may include a combination of vaccination and livestock management practices, including the following:
- Avoid co-grazing or mixing with other animal species, especially pigs.
- Avoid introducing new animals into a herd without quarantine, health assessment, and vaccination.
- Avoid bull- or boar-sharing for reproductive services.
Your veterinarian can provide specific recommendations based on your location, number of animals, risk factors and control options.

Preventing spread from animals to people
If animals are not treated completely, they may have the bacteria that causes leptospirosis in their urine for up to three months and spread it to people and other animals.
How to prevent spread
- Avoid urine or blood from the infected animal before it has received proper treatment.
- If you must have contact with animal tissues or urine, cover your wounds with a waterproof dressing and wear protective clothing like gloves and boots. This is especially important if your job puts you at risk (veterinarians, farm workers, and sewer workers).
- Always wash your hands after handling your animals or anything that might have animal urine or feces (poop) on it.
- If you're cleaning surfaces that may be contaminated from an infected animal, use antibacterial cleaning solution or a solution of 1 part household bleach in 10 parts water.
- Make sure your infected animal takes all prescribed medicine and follow up with your veterinarian.
Resources
- Merck Veterinary Manual:
- Protect Yourself from Leptospirosis after a Storm fact sheet
- Protect Yourself from Leptospirosis after a Storm fact sheet in Spanish