Leptospirosis

What is Leptospirosis?

Leptospira are spiral shaped bacteria. There are several species and subspecies or serovars. Specific serovars can cause different disease in different geographical areas. This bacterium likes to live in warm moist environments and is most often found in stagnant or slow-moving water. However, it can contaminate the soil for months after a flood.

Racoons, rats and other wildlife are common carriers of infection. Pets and humans can be exposed through contaminated wildlife urine. Although, Leptospirosis was traditionally considered a rural disease, the high prevalence of rats and racoons in urban areas and the increased movement of pets has contributed to the urbanization of this disease.

How is Leptospirosis transmitted?

Dogs, cats and humans can become infected by exposure to infected water, soil and urine. For example, your dog could become infected when a cut or skin abrasion come in contact with infected water, soil or urine. Alternatively, a dog could contract an infection by ingesting or being bitten by an infected rat/raccoon/dog.

Infection in dogs

After infection, the organism rapidly spreads in the blood stream inflaming blood vessels. In about 7 days fever, abnormal bleeding, bruising and tissue swelling can occur.

By two weeks, the bacteria reside in the kidneys causing inflammation and possible kidney failure. Leptospira's can stay in the kidney and be shed for months.

The second most affected organ is the liver. Toxins produced by the Leptospira can damage liver cells causing hepatitis and liver dysfunction. Similarly, these toxins can damage the lungs causing bleeding into the airways. This is a devastating form of the disease with a mortality rate of about 70%.

Other regions of the body, including the eye, pancreas, intestines, heart, muscle and joints, can show signs of inflammation secondary to leptospirosis infection.

Therefore, infection in one patient can look very different from infection in another. Young dogs tend to be more severely affected and individuals under 6 months may suddenly die without significant warning clinical signs.

Clinical signs can vary widely depending on the stage of disease, but can include fever, muscle soreness, lameness, vomiting, diarrhea, abdominal pain and increased urinating or conversely no urine production. For patients that have been infected for a longer period of time, the most common clinical signs are inappetence, vomiting and lethargy.

Treatment

Fortunately, Leptospirosis is susceptible to an antibiotic – doxycycline. Depending on the organs affected and the severity of disease, other supportive care may include intravenous fluids, anti-nausea medication to prevent vomiting, liver supplements and sometimes a blood transfusion.

Prognosis is good for patients diagnosed early and treated aggressively with intravenous fluids and antibiotics with survival rates between 50 and 90%.

Vaccination for Leptospirosis reduces the risk/severity of disease and should be considered in areas of risk.

Zoonotic Potential

It is important to note that people can contract Leptospirosis with young and immunocompromised people being at greatest risk. Human exposure can be through infected animal urine, or water/soil contaminated with urine from an infected animal.

Symptoms in humans are often flu like and can include headache, fever, muscle aches, vomiting and jaundice.