Leptospirosis is a disease caused by infection with a type of bacteria called Leptospira, which is frequently transmitted to dogs either through contact with urine from an infected animal or by wading or swimming in contaminated bodies of water. The bacteria enter a dog's bloodstream through small wounds in the skin and then infect the kidneys and sometimes also the liver. The bacteria can cause significant organ damage, which in some cases may result in the pet's death. Other species of animals, including humans, can also be infected with Leptospira bacteria.




Symptoms of leptospirosis can include fever, loss of energy and appetite, muscle and joint pain, vomiting, increased thirst and urination, yellow mucous membranes, and unusual bleeding or bruising. A veterinarian may be suspicious that a dog has leptospirosis based on the results of a physical exam, routine blood testing, and a urinalysis, but to reach a definitive diagnosis, blood work that looks for exposure to the bacteria or other types of disease-specific laboratory tests are necessary.




Treatment for leptospirosis includes hospitalization, antibiotics, and intravenous fluid therapy to support an infected dog's kidneys and liver until its condition becomes more stable. Dialysis may be necessary in severe cases. Because people and other animals can be infected with Leptospira shed in an infected dog's urine, strict quarantine procedures must be followed. Vaccines are available that can partially protect dogs against leptospirosis, but infection with some types of the bacteria is still possible. Allergic reactions to Leptospira vaccines are also fairly common, so some veterinarians do not routinely vaccinate all dogs against leptospirosis.


Written by: Jennifer Coates, DVM
Last reviewed: October 2, 2008