Overview of Leptospirosis in Dogs
Leptospirosis, commonly referred to as “lepto”, is a zoonotic disease that can pass from animals to humans. It is a bacterial disease that damages the liver and kidneys of dogs, sometimes resulting in renal failure and death. It is caused by a spirochete (spiral shaped bacterium) called a leptospire.
Leptospires live in fluids from infected animals, including urine, saliva, blood and milk. The disease is transmitted by direct contact with the fluids or with an infected animal. It is also transmitted by indirect contact such as vegetation, food and water, soil and bedding materials. Leptospires enter the body through mucous membranes or through breaks in the skin. The disease may be carried for years in animals without any apparent symptoms of the disease.
Any age, breed or sex of dog is susceptible to leptospirosis, although in general, young animals are more severely affected than adults. Large breed outdoor adult dogs are most commonly affected.
Leptospirosis can cause irreversible kidney damage, liver damage, uveitis (inflammation of the inner part of the eye), and damage to other organs.
What To Watch For
The first signs you might notice in your pet are flu-like symptoms. This may include several days of anorexia, vomiting, lethargy, depression and sometimes diarrhea or bloody urine. Other signs may include:
Diagnosis of Leptospirosis in Dogs
Your veterinarian will want to do a complete review of history and physical exam findings to develop a list of possible causes for your dog’s illness. In order to make a definitive diagnosis of leptospirosis, however, various diagnostic tests may be recommended.
Treatment of Leptospirosis in Dogs
If the disease is caught in time, it can usually be treated successfully with penicillin and tetracycline drugs. However, those with renal failure may or may not recover, or may recover only partial renal function.
In-depth Information on Leptospirosis in Dogs
Leptospirosis is still an important infectious disease of dogs, despite the fact that vaccines have been around for more than 30 years. It has a worldwide distribution and is caused by several distinct serovars (subtypes) of the organism Leptospira interrogans. The organism is a spiral shaped bacterium with hook shaped ends that makes a characteristic writhing and flexing movement while moving. There are many distinct subtypes of the leptospirosis organism, although five in particular are responsible for most cases of disease in dogs. Dogs contract leptospirosis either by direct contact with infected urine, bite wounds, eating infected tissue or during birth.
Wild animals like skunks, raccoons and opossums are a major source of infection, although pigs, rats and other animals may harbor the organism and serve as reservoirs of infection. Direct spread is enhanced by crowding of animals, such as in kennel situations. Indirect transmission can occur if susceptible animals are exposed to contaminated food, soil, water or bedding. Stagnant or slow-moving warm water provides an excellent habitat for the organism. This explains the increase in cases during periods of flooding.
Once the organism penetrates the body, it enters the bloodstream and multiplies rapidly and causes the blood vessels to become inflamed. The organism penetrates through the inflamed vessels and invades other organs like the kidneys, liver, spleen, eyes and reproductive tract. The body makes an immune response and eliminates the organism from most organs. Unfortunately, organisms tend to persist in the kidneys and can be released into the urine for several weeks or months. When the organism invades the kidney, sudden impairment of kidney function may result. Depending on how virulent, or infectious, the particular serovar of the organism is, and how strong an immune response the dog mounts, the damage can be mild or severe. Some serovars can cause sudden hemorrhage, liver damage, and most commonly, kidney damage.