Leptospirosis in Dogs

Leptospirosis is a disease caused by many different species and variants of Leptospira bacteria.

These bacteria can survive for long periods in surface water such as swamps, streams, and rivers, so infection is often spread through contaminated water.

The disease can affect almost all mammals, including people, and can range from mild or unnoticed infection to severe, life-threatening illness involving multiple organs in the body.

Dogs become infected through contact with contaminated urine or water, through bite wounds or damaged skin, by eating infected meat or the bodies of infected animals, or occasionally during birth.

After entering the body, the bacteria spread through the lymph system and bloodstream to many organs. If the dog survives the initial infection, the immune system can clear most of the bacteria, but they can remain hidden in the kidneys and reproductive tract. Infected dogs can then become carriers and shed bacteria in urine and genital fluids for months or even years.

Some leptospirosis infections cause no signs, while others lead to sudden and severe disease. The most common pattern in dogs begins with sudden onset of kidney disease. Signs can include sluggishness, loss of appetite, vomiting, dehydration, and back pain due to kidney inflammation. Changes in urination are common, ranging from increased urine production to very little or no urine. Acute kidney failure can progress to chronic kidney disease. The disease can also cause sudden liver failure, sometimes along with kidney disease, often leading to yellowing of the gums, skin, and eyes.

Other signs include muscle pain, stiffness, weakness, trembling, or reluctance to move. Some dogs develop bleeding disorders, which can appear as nosebleeds, bruising, or blood in the feces or vomit. Respiratory signs such as coughing or difficulty breathing can occur, as well as eye inflammation. Additional possible signs include vomiting, diarrhea, weight loss, fever or low body temperature, eye or nasal discharge, enlarged lymph nodes, and fluid buildup in the body.

Specialized lab tests can detect the bacteria in blood, urine, or samples of skin or other body parts. Other tests measure the body’s immune response to infection. Additional blood tests, urine tests, x-rays, and an ultrasound exam might be needed to determine which organs in the body are affected and to guide treatment.

Kidney failure and liver disease are managed with fluid therapy, antibiotics, and other supportive care in the hospital.

Vaccines are available for four of the most common types of leptospirosis in dogs, but they don't protect against all strains. Vaccination is usually recommended every year. Dogs that have been recently exposed to the bacteria might be given antibiotics for about 14 days to help prevent infection.

Because leptospirosis can spread to people, strict cleanliness is essential when handling infected or possibly infected animals. Contact with urine or blood from these animals should be avoided. Infected dogs should urinate only in areas that can be cleaned and disinfected, because the bacteria are killed by common disinfectants. If your dog is diagnosed with leptospirosis, contact your physician if you have any health concerns. Gloves should be worn when cleaning urine, and hands should be washed thoroughly after handling the dog, at least until antibiotic treatment is finished.