Leptospirosis in Dogs and Cats

What is Leptospirosis?

Leptospirosis is a bacterial organism that loves warm, moist environments. There are about 250 types of Leptospirosis. In the US, there are 4 to 10 types that can infect and cause illness in dogs, cats, and people. Lepto is also found in rodents, opossums, skunks, raccoons, and large animals like cows, horses, and pigs. Leptospirosis infections are most common in the summer and fall months, and after heavy rains or flooding. Leptospirosis can live outside a host and in the environment for months in optimal conditions.

How can my dog or cat become infected with Lepto?

Animals can get infected with Leptospirosis by coming into contact with infected urine, bite wounds, in-utero through the placenta or during mating, ingesting an infected animal, or from ingesting water, food, or soil that is contaminated.

Leptospirosis can penetrate through mucous membranes (gum tissue, conjunctiva of the eyes, pink tissue around the genitals, etc.) or broken skin like cuts and abrasions.

Cats can clear the infection without illness much better than dogs and people can. It’s rare for cats to become clinically ill, but not impossible.

What does Leptospirosis do in the body?

Once Leptospirosis is in the body, it rapidly enters the bloodstream leading to inflammation. The organism then moves to various tissues like the kidneys, eyes, liver, spleen, genitals, and central nervous system to replicate. This can take about 7 days to occur. The severe inflammation caused by Leptospirosis can lead to internal organ damage.

There are 4 manifestations of infection: peracute, acute, subacute, and chronic disease.

Clinical Symptoms of Leptospirosis Infections in Pets

• Death
• Fever
• Muscle tenderness
• GI upset such as vomiting and diarrhea
• Stiff gait
• Bleeding from the nose, rectum, in the vomit or stool, and/or small red mini bleeds under the skin or gums (called petechia)
• Yellow discoloration to the skin or eyes (also called jaundice or icterus)
• Little or no urine production or dramatic increase in urination and drinking
• Painful abdomen
• Abnormal heart rate and rhythm
• Abnormal breathing and coughing
• Changes to the eyes such as bleeding in the eye chambers, inflammation, etc.

Diagnosing Leptospirosis in Pets

Unfortunately, diagnosing Leptospirosis infection is not always a simple, single test. Previous vaccination against Leptospirosis can cause positive test results in some cases and the stage of infection can also affect the test’s ability to confirm infection.

Microscopic Agglutination Test (MAT): This is currently the most recommended test. Unfortunately, previous vaccination can cause positive results. Ideally, a blood sample is taken and submitted to the lab and another sample is taken and tested 2 to 4 weeks later. If the values rise in that 2 to 4-week interval, it is highly suggestive of an active infection.

ELISA Test: This test measures part of the immune system’s response to Leptospirosis. This test can detect recent/early infections better than the MAT test but isn’t ideal for chronic or longer duration infections.

PCR Test: This test looks for actual parts of the Leptospirosis organism in the body. It’s ideal to test both blood and urine since Lepto levels in the blood decline after 7-14 days and then the values are highest in the urine after that.

In-Clinic Tests: Some in-clinic Lepto tests can be run at your vet’s office. These tests are best run within 10-14 days after infection.

What treatment is available if my dog tests positive for Leptospirosis?

If your pet is showing clinical signs of Leptospirosis infection, they will likely be started on antibiotic treatment immediately as the test is being performed. The most common treatment is a 2 to 3-week course with an antibiotic called Doxycycline. Penicillin antibiotics may also be included in the treatment plan.

Depending on how ill your dog is, she may need to be hospitalized on IV fluids and medications to help her rehydrate, reduce nausea, and additional supportive care. She may need to be hospitalized for many days.

The survival rate with treatment is about 80-90%. Dogs with breathing abnormalities and severe kidney disease have a lower chance of survival.

About half of the dogs that develop illness from Leptospirosis will have some form of chronic kidney damage.

Be sure to use extreme care when handling your dog if they have Leptospirosis since this can also infect people. Wear gloves and goggles if you have to clean up urine. Avoid contact with the saliva.

How can I prevent or reduce my pet’s risk of Leptospirosis infection?

Controlling rodent populations and avoiding contact with large animals is one way to reduce infection.

Don’t let your dog or cat drink from stagnant or slow-moving water like puddles, ponds, or slow-moving creeks.

Vaccinate your dog! There are various Leptospirosis vaccines available against the most common types that cause illness in the US. The vaccine is given initially with a booster about 3 weeks later, then the vaccine is given yearly thereafter.

Read more:

Leptospirosis in Dogs

Leptospirosis and Your Pet: A CDC Factsheet

Need to speak with a veterinarian regarding leptospirosis in your pet or another condition?

Click here to schedule a video consult to speak to one of our vets. You can also download the FirstVet app from the Apple App Store and Google Play Stores.