Leptospirosis, a nasty disease that can infect both animals and humans, is caused by a specialized type of bacteria known as a spirochete. Corkscrew-shaped spirochetes enter the body by burrowing directly into the skin, then spread out and make themselves at home in the liver, kidneys, eyes, reproductive organs, and central nervous system. Once in the kidneys, Leptospira bacteria begin to reproduce, and are passed back out into the environment through infected urine.
All animals can be at risk for developing Leptospirosis, including wildlife (raccoons, skunks, deer, rats, foxes, opossums, rabbits, and snakes), livestock (cows, sheep, and pigs), and pet animals (dogs, cats, horses, reptiles, and birds).
Leptospirosis is found almost everywhere, from isolated rural areas to large cities. It’s more prevalent in areas with warm climates and high annual rainfall, since these bacteria thrive in standing water and wet soil (where they can remain infectious for up to 6 months). They’re also extremely common in recreational ponds and lakes.
Although Leptospirosis is not a new disease, recently the rates of infection for dogs and cats have been rising in the United States and Canada. This is probably due to the fact that as humans continue to invade natural habitats, the likelihood of family pets coming into contact with infected wildlife increases. Also, the tests now being used to diagnose this disease are much better than they used to be.
Leptospira bacteria can infect both dogs and cats, but it’s far more common in dogs.
How Do Dogs Get Leptospirosis?
Leptospira bacteria are most commonly transmitted through the urine of infected animals. Dogs usually become infected by drinking, swimming in, or walking through water contaminated with the bacteria, which is able to enter the dog’s body through cuts in the skin or via the mucous membranes of the dog’s eyes, nose, and mouth.
Risk of exposure increases during the summer and early fall, and during periods of high rainfall and flooding. Hunting and sporting dogs, and dogs who live on farms or near wooded areas are at greater risk of contracting Leptospirosis.
Dogs can also contract the disease through the bite of an infected animal, by eating infected carcasses of other animals, or through exposure to other dogs who are infected. In rare cases, Leptospirosis can be transmitted through breeding, or passed through the placenta from a mother dog to her puppies.
After a dog is infected, the bacteria spread throughout the bloodstream and cause fever and other flu-like symptoms. Once the dog’s body fights off the infection, most usually recover. However, Leptospira bacteria can remain in the liver and kidneys, causing severe organ damage. Young dogs with immature immune systems are at the highest risk for complications.
Symptoms Of Leptospirosis
The clinical signs of Leptospirosis may vary. Some dogs don’t show any signs of being ill, some have mild symptoms that spontaneously disappear on their own, and others can develop such severe illness that it leads to death.
When symptoms do occur, they usually appear between 4 and 12 days after exposure. According to Dr. Karen Becker, DVM, clinical signs depend on the health of the dog and the potency, or virulence, of the particular species of Leptospira bacteria that is present.
Flu-like symptoms are the most common, and include:
- Loss of appetite
- Vomiting, possibly tinged with blood
- Diarrhea, with or without blood
- Rapid dehydration
- Runny nose
- Mild swelling of the lymph nodes
Other symptoms may include:
- Sore, stiff muscles; reluctance to move
- Increased thirst and urination
- Inability to urinate (a sign of kidney failure)
- Painful eye inflammation
- Accumulation of fluid in the legs, chest, or abdomen
- Bloody vaginal discharge
- Dark red speckled gums
- Difficulty breathing, rapid breathing, or irregular heart rate
Since Leptospirosis primarily affects the liver and kidneys, in severe cases, the disease can lead to kidney or liver failure. If the liver becomes damaged, jaundice (yellowing of the skin, eyes, and gums) may occur.
Blood clotting problems and bleeding disorders can also develop, resulting in nosebleeds and tiny pinpoint red spots (called petechiae) on the skin or gums. In rare cases, Leptospirosis can cause sudden hemorrhaging in the lungs, leading to difficulty breathing and respiratory distress.
Leptospirosis can be diagnosed based on a dog’s history of exposure and symptoms, but since many of these signs can also be seen with other diseases, veterinarians usually recommend additional testing. This can include blood work, urinalysis, a blood culture (to check for the presence of the bacteria), and sometimes ultrasound or x-rays.
A specialized blood test called a microscopic agglutination test can also be done, which measures the body’s immune response to an infection by examining the amount of antibodies in the blood.
Treatment Of Leptospira Infection
Leptospirosis is usually treated with antibiotics and supportive care, including intravenous fluids to combat dehydration caused by vomiting and diarrhea. If the patient is unable to keep food down, a feeding tube can be used to deliver nutrients, and if hemorrhaging is an issue, a blood transfusion may be necessary.
When treated early and aggressively, chances of recovery are good; however, permanent liver and kidney damage is always a risk. Once the patient has recovered, antibiotics are usually prescribed for a 4-week period, sometimes longer.
Protecting Yourself From Leptospirosis
Leptospirosis is a zoonotic disease, which means it can be transmitted from animals to people. As in dogs, infection in humans causes flu-like symptoms and can result in organ damage. In the U.S., most cases of leptospirosis in people result from recreational activities involving water. Children are at the highest risk when it comes to acquiring Leptospirosis from an infected pet.
If your dog has been diagnosed with Leptospirosis, you can take the following precautions to protect yourself and other members of your household (both humans and pets):
- Avoid all contact with your dog’s urine. If your dog urinates in the house, PUT ON GLOVES and quickly clean the area with a household disinfectant.
- Encourage your dog to urinate outside in a dry area, away from standing water or areas where children or other pets have access.
- Wash your hands thoroughly after handling your dog, and make sure any children do the same.
- Give the antibiotics prescribed by your veterinarian consistently until they are all gone.
- Wear protective gloves when handling any fluid or waste products from your dog, and immediately clean up any urine, vomit, or diarrhea. Leptospira bacteria can still be shed in urine for several weeks after treatment, so good hygiene and handling practices are the best prevention against the spread of infection.
- Avoid any water that might be contaminated with Leptospira bacteria, especially water that is stagnant. Keep your dog away from ponds and slow-moving water, and don’t allow him to drink from lakes, rivers, or puddles.
Controversy Surrounding The Leptospirosis Vaccine
Although there is a vaccine available against Leptospirosis, many veterinarians don’t recommend it, for several reasons.
First, the vaccine protects against the 4 most common strains of Leptospirosis, but there are more than 20 strains of the bacteria that can infect your dog, so a vaccinated dog can still contract the disease. Also, since Leptospirosis is caused by a bacteria (not a virus), the vaccine is known as a “bacterin” vaccine. Unlike viral vaccines, bacterin vaccines do not prevent infection; they only decrease the severity of the symptoms if the dog becomes ill. This vaccine does not provide long-term immunity and needs to be given every year (some researchers say it doesn’t even last a full year).
The Leptospirosis vaccine has also been shown to cause frequent and severe vaccine reactions, including swelling of the face and at the injection site, vomiting, diarrhea, anaphylaxis, and in rare cases, bleeding disorders. According to the American Veterinary Medical Association, the Leptospirosis vaccine is not considered a “core” vaccine, which means it is not recommended for all dogs in all environments. For these reasons, the potential risks of the Leptospirosis vaccine may outweigh the benefits.
If you have concerns about whether to vaccinate your dog against Leptospirosis, be sure to talk with your veterinarian.
A Preventable (And Treatable) Disease
If you live in an area where Leptospirosis is prevalent, make sure your pet’s immune system is strong and healthy. You can also take precautions to ensure that he or she isn’t put in a situation where they can be exposed to Leptospira bacteria.
If you have a healthy pet who suddenly becomes lethargic, develops a fever, is urinating more than usual or is urinating blood, call your veterinarian immediately. Although Leptospirosis can have serious complications, fortunately it’s a very treatable infection when caught early.
Have you ever had a pet who was diagnosed with Leptospirosis, or known anyone who has? Please share your story with us in the comments below!