Leptospirosis in Dogs: Signs, Treatment, and Prevention

How dogs catch it

Leptospira bacteria live in the kidneys of infected animals and leave the body in urine. Rodents can carry them for life without looking sick. Wildlife, farm animals, and other dogs can shed them too.

Dogs are usually infected when contaminated water or soil touches the gums, eyes, nose, or broken skin. Drinking from puddles, ponds, ditches, or slow streams is a common route. Swimming, wading, and sniffing wet ground where rats live also carry risk. Less often, dogs are infected through bite wounds, by eating dead rodents or raw tissue from infected animals, or before birth from an infected mother.

The bacteria do best in warm, wet conditions. In Europe, most cases are seen in summer and autumn, and cases often rise after heavy rain or flooding. City dogs are at risk as well, because rats live in cities too. Small dogs from urban areas are among the cases reported in recent years. Signs usually appear a few days to two weeks after exposure.

Signs to watch for

Some infected dogs have a mild illness or no signs at all. Others become seriously ill within days. The kidneys are affected most often, and the liver is often involved too. Owners may notice one or more of these signs.

• Tiredness, weakness, or low mood
• Loss of appetite
• Fever or shivering
• Vomiting or diarrhea
• Drinking and urinating more than usual, or urinating much less
• Sore muscles, stiffness, or reluctance to move, sometimes with a hunched back from belly or back pain
• Yellow gums, skin, or whites of the eyes (jaundice)
• Red eyes, or discharge from the eyes or nose
• Tiny red spots or bruises on the gums or skin, nosebleeds, or blood in urine, vomit, or stool
• Coughing or fast breathing

These signs overlap with many other illnesses. If you see them, call your veterinarian and mention any recent contact with standing water, rats, or farm animals.

When it is an emergency

Leptospirosis can get worse quickly. Without treatment, severe kidney damage can develop within days. Take your dog to a veterinarian or an emergency clinic right away if it has trouble breathing or coughs up blood, has yellow eyes or gums, passes very little urine or none, keeps vomiting, bleeds from the gums or nose, or collapses.

One form of the disease, called leptospiral pulmonary hemorrhage syndrome, causes bleeding into the lungs. It has been reported in dogs in several European countries and is one of the most dangerous forms. A dog that may have leptospirosis and starts to struggle for breath needs urgent care.

How vets diagnose it

Your veterinarian will usually start with a physical exam, blood tests, and a urine test. These show whether the kidneys and liver are affected and how badly. Chest X-rays or an ultrasound of the belly may follow.

To confirm leptospirosis, vets use tests that find the bacteria's genetic material in blood and urine (PCR), or tests that look for antibodies. Antibodies take several days to rise, so a second blood sample one to two weeks later is sometimes needed. Recent vaccination can also affect antibody results, which is one reason your vet will ask about your dog's vaccine history. When the signs fit, vets often start treatment before the results come back, because early treatment makes a difference.

How it is treated

Leptospirosis is treated with antibiotics. Most dogs with clear signs need a hospital stay, at least at first. Care usually includes fluids through a vein, medicine for nausea, pain relief, and nutrition support. Kidney and liver values are rechecked often.

Once the dog can keep food and tablets down, antibiotic tablets usually continue at home. This part of treatment typically lasts about two weeks and is meant to clear the bacteria from the kidneys, so the dog stops shedding them in urine. It is recommended to finish the full course as prescribed, even if your dog seems well.

Dogs whose kidneys stop producing urine may need dialysis, which is offered at some specialist and university hospitals. Dogs with bleeding in the lungs may need oxygen and intensive care.

Many dogs make a full recovery with early treatment. Some are left with long-term kidney or liver problems and need follow-up blood and urine tests. Your veterinarian can tell you what to expect for your dog.

Risk to people and other pets

Leptospirosis is a zoonosis, which means it can pass between animals and people. People can catch it the same way dogs do, through contaminated water or soil, often linked to rats. Catching it from a pet dog is uncommon, but it does happen and can be serious. In people it often starts like the flu and can go on to affect the kidneys and liver.

An infected dog sheds the bacteria in its urine, and the risk is highest before antibiotics begin. While your dog is being treated, and until your vet says otherwise, these steps are recommended.

• Wear rubber gloves when cleaning up urine or anything soiled with it, and wash your hands well afterward
• Clean urine spots indoors with a household disinfectant
• Walk your dog to urinate away from standing water and from places where children, other people, or other animals spend time
• Cover any cuts on your hands with a waterproof dressing

If anyone in the home develops a fever or a flu-like illness, tell the doctor that the dog has leptospirosis. Other dogs in the home can be infected through the sick dog's urine, so ask your vet whether they need to be checked, treated, or vaccinated. Cats can be infected too, but illness in cats is uncommon.

Vaccination and prevention

Vaccination is the main way to protect a dog. Leptospirosis is found in dogs across Europe, and current guidelines recommend vaccinating all dogs wherever the disease occurs and suitable vaccines exist. The first course is two doses given two to four weeks apart, followed by one dose a year. Protection does not last as long as it does with the vaccines against distemper and parvovirus, so yearly boosters are recommended. If 18 months or more have passed since the last dose, or the history is unknown, guidelines suggest starting again with two doses.

There are many types of Leptospira, sorted into groups called serogroups, and a vaccine mainly protects against the groups it contains. Older vaccines used in Europe covered two serogroups. Many current ones cover four and are often called L4 vaccines. Your veterinarian will choose a vaccine suited to your area. Vaccination lowers the risk a great deal but does not cover every strain. Modern leptospirosis vaccines appear to be about as safe as other routine dog vaccines.

A few everyday habits help too.

• Carry fresh water on walks so your dog is less tempted to drink from puddles
• Keep your dog away from ponds, ditches, and slow water, especially after heavy rain or flooding
• Control rats around the home, and keep food and trash in closed containers
• Avoid feeding raw meat from unknown sources, and stop your dog from eating dead animals

Rescued and newly adopted dogs

Stray dogs are often unvaccinated and live close to rats and standing water. A study of stray dogs held in 11 shelters in Serbia found antibodies to Leptospira in about 5 percent of them, a sign of past exposure. Dogs can also carry the bacteria in their kidneys and shed them in urine without looking sick.

At Paw Squadron, the first stops after every rescue are the vet and a bath. Each animal gets a checkup, deworming, and treatment against fleas and other parasites. Before adoption, every animal also receives vaccinations and a microchip.

When you adopt, ask for the vaccination record and look for a leptospirosis vaccine and its date. Book a visit with your own veterinarian soon after your dog arrives, and ask when the next leptospirosis dose is due. If the record is unclear, your vet may suggest restarting with two doses. In the first weeks, keep your new dog away from ponds and puddles and watch for the signs listed above.

You can find more health guides in PawPedia, and answers to common adoption questions on our FAQ page.