Leptospirosis is a serious bacterial infection caused by spiral-shaped bacteria called Leptospira. The bacteria are shed in the urine of infected wildlife, especially rats, raccoons, and skunks, and they survive for weeks to months in warm, wet soil and standing water. Dogs usually pick up the infection by drinking from or splashing through contaminated puddles, ponds, and streams, or by sniffing soil where infected animals have urinated. The bacteria slip in through the mouth, nose, or a small cut, then travel in the bloodstream to the kidneys and liver, where they can cause sudden organ failure. Because leptospirosis can also infect people, it is one of the most important zoonotic diseases dog owners need to understand.
Signs and Symptoms
Signs typically appear about one to two weeks after exposure, and they range from mild to life-threatening. Early warning signs look like many other illnesses: fever, shivering, tiredness, muscle soreness, and a dropped appetite. As the kidneys and liver come under attack, you may see vomiting, diarrhea, increased thirst, and changes in urination, from noticeably more urine to very little or none. Yellowing of the gums, eyes, or skin (jaundice) points to liver involvement. Some dogs develop bleeding problems, shown as nosebleeds, blood-tinged vomit or urine, or small red spots on the gums, and severe cases can bring difficulty breathing from lung hemorrhage.
When to See a Vet
Treat leptospirosis as urgent. If your dog is vomiting, unusually tired, or off food, and has had access to puddles, ponds, or wildlife areas, call your veterinarian the same day. Seek emergency care right away if your dog is jaundiced, is producing little or no urine, has unexplained bruising or bleeding, or is struggling to breathe. While waiting for the appointment, avoid contact with your dog’s urine, wear gloves when cleaning accidents, and wash your hands after handling the dog, because infected dogs can pass the bacteria to people.
Common Vet-Directed Treatments
Diagnosis combines blood tests, a urinalysis, and specific testing such as PCR and antibody (MAT) tests, since the signs mimic many other diseases. Treatment starts quickly and is built on two pillars: antibiotics to kill the bacteria, most commonly a two-week course of doxycycline, and intensive supportive care. Most dogs need hospitalization with intravenous fluids to flush and support the kidneys, plus anti-nausea medication, pain relief, gut protectants, and nutritional support. Severe cases may need oxygen therapy or referral for dialysis while the kidneys recover. When treatment begins early, most dogs recover well, though some are left with chronic kidney or liver damage that needs long-term monitoring.
Home Care During Recovery
- Give the full antibiotic course exactly as prescribed, even if your dog looks completely recovered.
- Keep the dog separated from other pets until your vet confirms the bacteria are cleared.
- Wear gloves to clean up urine, disinfect surfaces with a household disinfectant or diluted bleach, and wash hands thoroughly.
- Walk the dog in an area where urine can dry quickly in sunlight and other animals cannot drink from it.
- Watch appetite, thirst, and urine output daily, and attend every follow-up blood test your vet schedules.
Prevention
Vaccination is the strongest protection. Modern four-strain vaccines are given as two initial doses three to four weeks apart, followed by an annual booster, and many veterinary groups now recommend the vaccine for all dogs as a core vaccine. Alongside the vaccine, reduce everyday exposure: do not let your dog drink from puddles, ponds, or slow streams, carry fresh water and a bowl on walks, keep rodents away from your yard, and stop your dog from sniffing or scavenging wildlife. A veterinarian’s discussion of the disease and the vaccine decision is included below for pet owners weighing the choice.
Disclaimer: This article is for educational content only and is not a substitute for professional veterinary advice. If your pet is unwell, please contact a licensed veterinarian promptly.