Leptospirosis in Dogs - Contagious Bacterial Infection
Leptospirosis in Dogs - Contagious Bacterial Infection
Important note: Fidello is not a veterinarian. This page is meant to inform you and does not help you reach a diagnosis. If you are unsure about your dog's health, or you recognise the signs described below, always contact a veterinarian. If your dog suddenly seems lethargic, is vomiting, has a reduced appetite, shows a yellowish tinge to the gums or skin, or is clearly urinating less, go straight to a veterinarian or animal hospital: leptospirosis can progress to serious kidney or liver failure within a few days.
Leptospirosis is a bacterial infection that dogs can pick up from contaminated water, damp soil, or the urine of other animals. The illness can be mild and easy to miss, but it can also strike suddenly and severely, damaging the kidneys and liver. Leptospirosis is also a zoonosis: the bacteria can infect people too, which is why hygiene in and around the home deserves extra attention alongside your dog's own health with this particular illness.
What is leptospirosis?
Leptospirosis is caused by bacteria of the genus Leptospira, spiral-shaped microorganisms of which several variants (serovars) exist worldwide. These bacteria are shed in the urine of infected animals, particularly rodents and other wildlife, and can survive for weeks to months in damp soil, puddles, ditches, and other standing water. A dog becomes infected through contact with contaminated water or soil, via mucous membranes (eyes, nose, mouth) or small breaks in the skin, or by drinking contaminated water. Once inside the body, the bacteria spread through the bloodstream and settle mainly in the kidneys and liver, where they cause inflammation and tissue damage.
Which dogs are at risk?
Leptospirosis is not linked to a particular breed; the risk depends mainly on exposure. Dogs that regularly swim in or drink from standing or slow-moving water, dogs that spend a lot of time in rural, damp, or marshy areas, and dogs in contact with wildlife or rodents carry a higher risk. Dogs that are inadequately vaccinated or no longer up to date, as well as dogs that travel abroad often or roam in wildlife-rich areas, are also more often mentioned as a risk group. These indications are broadly documented, but the actual likelihood depends heavily on the local situation; feel free to discuss the risk for your dog with your veterinarian.
Symptoms
Early signs are often general and easy to miss: mild fever, lethargy, reduced appetite, vomiting, muscle pain (for example a stiff gait or discomfort when the back is touched), and a temporarily increased thirst with more frequent urination. Signs that call for urgent care are: clearly reduced or no urine output, persistent vomiting, a yellowish tinge to the gums, the whites of the eyes, or the skin, bleeding (for example blood in stool, vomit, or urine), breathlessness or rapid breathing, and general collapse. Not every dog with leptospirosis shows all of these signs; severity can vary widely from dog to dog and depending on the bacterial variant involved.
When to see a veterinarian
Always contact your veterinarian for persistent lethargy, reduced appetite, or vomiting, even if the symptoms initially seem mild. If you notice a yellowish tinge to the gums or skin, clearly reduced urine output, bleeding, or breathlessness, no waiting time is justified: go to a veterinarian or animal hospital that same day. When booking the appointment, mention that you suspect leptospirosis, especially if your dog has recently swum in or drunk from standing water, so the practice can take precautions, partly because of the infection risk to people and other animals.
How is it diagnosed?
A veterinarian diagnoses leptospirosis based on blood tests, including a test that detects antibodies against the bacteria (MAT test) and/or a PCR test that detects the bacteria's genetic material, usually combined with blood values reflecting kidney and liver function and a urine test. Because early blood values are not always abnormal and the first test result sometimes needs to be repeated, reaching a confident diagnosis can take some time. This page cannot provide a diagnosis; only a veterinarian can determine, after examination, whether leptospirosis is causing the symptoms and how serious the situation is.
Treatment in outline
Treatment for leptospirosis usually consists of a course of antibiotics prescribed by the veterinarian, with duration and type tailored to your dog's situation, often combined with supportive care. In cases of kidney or liver damage, hospitalisation may be needed for intravenous fluids, anti-nausea medication, and close monitoring of blood values and urine output. In severe cases with acute kidney failure, more intensive support may be required. The final approach, treatment duration, and prognosis are always determined by the treating veterinarian and vary from dog to dog, depending on how quickly treatment starts and how much damage has already occurred.
What you can do yourself
Because leptospirosis is a zoonosis, hygiene matters while your dog is ill or being treated: wash your hands after contact with urine, faeces, or vomit, use gloves where possible, and clean contaminated areas with a suitable disinfectant in consultation with your veterinarian. Keep sick dogs separated from other pets and from areas where children play until your veterinarian confirms this is no longer necessary. Complete a prescribed course of antibiotics in full, even once your dog seems better again, and make sure your dog gets enough rest during recovery. Contact your own doctor if you develop flu-like symptoms yourself after exposure.
Prevention
A vaccine exists against some of the Leptospira variants; discuss with your veterinarian whether vaccination makes sense for your dog, depending on lifestyle, travel habits, and local risks. Also limit exposure by not letting your dog drink from or swim in standing or murky water such as puddles, ditches, and shallow ponds, especially after rainfall, and keep food and waste inaccessible to rodents and other wildlife around your house or garden. Complete elimination of the risk is not possible, but these measures can reduce the chance of infection.
Living with leptospirosis
Dogs that are treated in time often recover well, although healing from serious kidney or liver damage can take weeks and sometimes leaves lasting effects, such as reduced kidney function in the longer term. After an infection has passed, your veterinarian may advise continuing to monitor blood and urine values for a while, even once your dog seems fit again. For dogs with permanent kidney damage, an adjusted lifestyle may be needed, with extra attention to fluid intake and regular check-ups; this too is best arranged together with your veterinarian.
Frequently asked questions
Is leptospirosis contagious to people?
Yes, leptospirosis is a zoonosis and can pass from dogs to people, mainly through contact with urine. Good hygiene while your dog is ill is therefore important.
Can a vaccinated dog still get leptospirosis?
Vaccination does not protect against every variant of the bacteria and offers no absolute guarantee; a vaccinated dog can in rare cases still become infected, usually with a milder course.
How quickly can leptospirosis become serious?
In some dogs, the illness can worsen within a few days to acute kidney or liver failure, which is why prompt recognition and veterinary care matter.
Can my dog get leptospirosis more than once?
Yes, a previous infection does not provide lasting protection against every variant of the bacteria; renewed exposure can lead to infection again.
Conclusion
Leptospirosis is a bacterial infection that dogs pick up from contaminated water or contact with (the urine of) other animals, and that, left untreated, can lead to serious kidney and liver damage. The illness ranges from mild to acutely severe, and because the bacteria can also infect people, both prompt veterinary care and good hygiene matter. Vaccination, avoiding standing water, and staying alert to early signs help reduce the risk, and timely treatment gives most dogs a good chance of recovery.
Finally
Finally: this article does not replace a visit to the veterinarian. Fidello does not provide diagnoses or prescribe treatments. If in doubt, if symptoms persist, or in case of urgent signs, a veterinarian is always the right next step.