Leptospirosis is an infectious disease that occurs worldwide and is emerging as a more common diagnosis in the Puget Sound area.
It is caused by the spiral-shaped bacteria Leptospira, of which there are several serovars (strains) of significance. There are 8 main serovars that cause disease in dogs; meanwhile cats can be infected but rarely become ill.
How Does a Pet Become Infected with Leptospira?
Leptospira are carried by reservoir hosts that do not show clinical signs, but shed the bacteria in their urine. A pet gets exposed when it comes in contact with infected urine.
Historically, we thought of leptospirosis as a disease of rural areas. However, with increased urbanization/suburbanization of our previously undeveloped land, wildlife is more prevalent in our shared spaces. In our area, we worry about raccoons, rodents, and farm animals as carriers.
Last year we had 2 patients diagnosed from Bothell. It is especially prevalent in wetter weather so we see more cases here in the fall.
The bacteria enter the body through the mouth, nose, eyes, or a skin break, then spreads through various body organs. The organism is ultimately cleared by most tissues, but can have an overwhelming effect on the kidneys and/or the liver.
What are the Symptoms of Leptospira Infection?
Clinical illness develops about one week after exposure, and the dog may begin exhibiting flu-like symptoms. A fever often occurs, along with muscle weakness, loss of appetite, and depression. Vomiting and dehydration can follow. If there is liver involvement, the skin may appear jaundiced.
However Leptospirosis can be difficult to diagnose because the signs can be very non-specific. Your veterinarian will likely suspect it in any dog that presents with acute kidney failure.
A confirmatory diagnosis can be made from a blood test. These results will indicate which serovar is involved in the disease.
How is Leptospirosis Treated?
Treatment involves intravenous fluid therapy, supportive care, as well as antibiotics to clear the organisms. With prompt diagnosis and treatment, chances of survival are good.
Fortunately, there now exists several efficacious vaccines to protect against leptospirosis. They provide immunity to four different serovars, and there is some evidence to indicate cross-protection from some others. The vaccines are initially administered in a series of 2 injections, followed by yearly revaccination.
Can Humans Contract Leptospirosis?
Yes… Lepto is a “zoonotic” disease, which means that it can be transmitted to humans and can occur through contact with infected urine or contaminated water.
The majority of people affected have subclinical disease or very mild symptoms. However, some people can suffer from severe disease, and even death. For this reason, any cases diagnosed in pets must be reported to the local health department.