Canine Leptospirosis

Canine Leptospirosis

By Gordon Bijvoet

Leptospirosis is a significant disease that commonly affects canines worldwide, and has the potential to infect and become harmful to both canines and the people coming into contact with the organism. Leptospirosis is caused after animals are exposed to the filamentous gram negative motile spirochetes belonging to the genus Leptospira. All warm blooded animals are susceptible to the bacteria; however, canines account for most of the small animal cases. When it comes to diseases like leptospirosis, it is important to fully understand all aspects of the disease and take proper preventative measures to decrease the likelihood of pets, pet owners, and veterinary professionals becoming infected.

The organism thrives in warm, moist, and alkaline environments in temperatures between 0-25 degrees Celsius, where it can remain viable for months. This makes leptospirosis very prevalent in areas with stagnant water, and the number of cases increases between the months of July through November. Infected animals can contaminate the environment after shedding the bacteria in the urine. Most infections occur after the bacteria enters through abraded mucous membranes or skin, but other routes of transmission can occur. Indirect transmission can occur after coming into contact with the organism in the environment and direct transmission can occur after injection through animal bites, ingestion of infected tissues, transplacental transmission from infected dams to fetuses, and venereal transmission.   

Once an animal has become inoculated, the bacteria initially enters the bloodstream and tissues, and then can cause inflammation damaging many organs in the body. Leptospira resides in the kidneys, which is the most common organ affected, followed by the liver. Depending on the severity of the infections, animals can display symptoms from lethargy, anorexia, and fever, to abortions, blood disorders, and organ failure. Humans display similar symptoms and meningitis can occur leading to severe headaches. If leptospirosis is suspected in a small animal, a veterinarian should be consulted in order to make the diagnosis through urine or blood samples. This can be done by running a paired serology at two or four week intervals, polymerase chain reaction (PCR), or microscopic agglutination test (MAT). If an animal tests positive, appropriate measures should be taken to decrease the extent of the disease and improve the outcome of the patient. The prognosis of infected dogs depends on many factors, but survival rates are generally around 80-90%. The extent of the disease determines the appropriate treatment plan, but it often involves fluid therapy and a course of antibiotics.

While treatment is often successful, preventative care is very important. Vaccines are available with multiple serovars. It is important to remember that the vaccine offers protection from disease, but does not prevent infection of the organism. When determining if the Leptospira vaccine is appropriate for a pet, a risk assessment of the dog should be performed, and high risk dogs should be vaccinated. High risk dogs include hunting and working dogs, dogs that spend time outdoors, and dogs in endemic areas. The 4-way killed Leptospira vaccine with serovars canicola, icterohaemorrhagiae, pomona, and grippotyphosa serovars should be used. According to the American Animal Hospital Association (AAHA) Canine Vaccination Task Force, dogs can start being vaccinated at twelve weeks of age, boostered two to four weeks later, and then vaccinated every twelve months after that. Vaccinating against Leptospira is an inexpensive and effective way to protect canines from disease associated with leptospirosis.

Leptospirosis is a serious disease for both humans and their pets. This organism is found worldwide and is easily transmitted among species, including humans, stressing the importance of taking multiple measures to decrease exposure. Increasing one’s knowledge base, vaccinating appropriately, and preventing contact with the bacteria are easy ways to offer protection. With collaborative efforts of both veterinarians and pet owners, the incidence and exposure to leptospirosis can greatly be decreased, and lead to a better quality of life among pets and their owners.


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