A Real Threat to Dogs and Their People

The District Vet

photo: Andrew Lightman

When thinking of disease hazards to dogs, most people are aware of rabies, parvovirus, and kennel cough, but leptospirosis should not be ignored, especially in our urban environment. Leptospirosis is a bacterial disease that may infect domestic animals, wildlife, and humans. It may cause fever, liver failure, kidney failure, abortion, and even death. It is of particular concern as it is a zoonotic organism, meaning that it can be passed from animals to humans. Leptospirosis has been seen in a number of dogs here in the city. Of note, the disease is rarely seen in cats.

Leptospirosis is spread from animal to animal via urine. This may occur from direct contact with contaminated urine, but is most frequently transmitted via contaminated water sources, such as stagnant puddles, ponds, and creeks. It may also be found in soil, contaminated bedding materials, or dead animals, or be transmitted via bites. In the city the main hazard is from rats and raccoons, but other wildlife may be vectors. The disease is most common in warmer times of the year in the DC metro area but may be found year-round, especially in southern climates.

Initial clinical signs of leptospirosis are nonspecific and can look like many illnesses. Fever, lethargy, increased thirst and urination, vomiting, dehydration, loss of appetite, and jaundice (yellowing of the mucous membranes and skin) are the most common signs. But some dogs may never even show signs of illness. These dogs have the potential to not appear ill but may still spread the bacterium to other animals. Oftentimes the infection is not diagnosed until late in the disease process.

The bacterium is most damaging to the liver and may cause liver failure. The kidneys don’t fare much better. Liver failure frequently results in yellowing of the skin, and kidney failure is seen as either not producing urine or producing too much urine, leading to dehydration.

Leptospirosis is a differential diagnosis in any dog that presents with kidney failure or liver failure (or both), or presents simply not feeling well. In addition to a physical examination and thorough history-taking, blood and urine tests may be performed to assess organ function and to look for markers of leptospirosis. An ultrasound of the abdomen or X-rays may also be helpful in the proper diagnosis.

Treatment involves antibiotics, hospitalization, fluids therapy, nutritional support, and supportive care. The likelihood of recovery is good when the disease is caught early and treated aggressively, but some dogs may not respond and others may suffer permanent damage to the liver and kidneys. Dogs may sometimes benefit from kidney dialysis, which allows the kidneys time to recover. 

In households where a dog has been diagnosed with or is suspected of having leptospirosis, family members should contact their physician immediately. Remember, leptospirosis can be passed to people.

The best ways to prevent leptospirosis include vaccination, decreasing the exposure to contaminated water (stagnant ponds, puddles, rivers, marshes), and minimizing contact with dead animals, especially rats. The vaccines are effective at protecting dogs for at least a year and are seen as being safe. They are no more likely to cause adverse reactions than any other vaccine commonly administered.

When assessing your dog’s health at annual physical examinations, ask your veterinarian if it is appropriate to vaccinate your dog against leptospirosis. Many shelters and rescues do not provide it as part of their routine vaccination series. Owing to the ubiquitous nature of the bacterium, your dog may benefit from the vaccine.


Dan Teich, DVM, is at District Veterinary Hospital, 3748 10th St. NE, Washington, DC 20017; 202-827-1230 and desk@districtvet.com.