Infectious disease · Updated 2026-09-29
Canine leptospirosis
A bacterial infection spread through contaminated water and urine that can cause sudden kidney and liver failure — and can infect people.
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Signs to watch for
- Fever and shivering
- Vomiting and diarrhoea
- Marked thirst changes
- Jaundice (yellow gums or eyes)
- Muscle pain and reluctance to move
- Reduced urination
Causes and risk factors
Leptospira bacteria survive in stagnant water and wet soil and enter through mucous membranes or skin cuts. Rat urine is a classic source.
How veterinarians diagnose it
Blood and urine tests, including PCR and antibody titres, alongside kidney and liver values. Early treatment often begins before confirmation.
Treatment and management
Hospital care with intravenous fluids and specific antibiotics. Barrier nursing is needed because urine from infected dogs is contagious to people.
Prevention
Annual leptospirosis vaccination, avoiding stagnant water, and rodent control around the home.
Outlook
Guarded to good depending on organ damage; early intensive care greatly improves survival.
Common questions
- What are the signs of canine leptospirosis?
- Fever and shivering; Vomiting and diarrhoea; Marked thirst changes; Jaundice (yellow gums or eyes); Muscle pain and reluctance to move; Reduced urination.
- What causes canine leptospirosis?
- Leptospira bacteria survive in stagnant water and wet soil and enter through mucous membranes or skin cuts. Rat urine is a classic source.
- How is canine leptospirosis diagnosed?
- Blood and urine tests, including PCR and antibody titres, alongside kidney and liver values. Early treatment often begins before confirmation.
- How is canine leptospirosis treated?
- Hospital care with intravenous fluids and specific antibiotics. Barrier nursing is needed because urine from infected dogs is contagious to people.
- Can canine leptospirosis be prevented?
- Annual leptospirosis vaccination, avoiding stagnant water, and rodent control around the home.
- When should I contact a veterinarian?
- Suspected leptospirosis is an emergency. Wear gloves when handling the dog's urine and tell your doctor about exposure if you become unwell.
Preparing for a canine leptospirosis consultation
- Record when these signs began and how they changed: Fever and shivering; Vomiting and diarrhoea; Marked thirst changes. Record appetite, water intake, toileting and any medicines or supplements.
- The listed urgency is emergency; worsening breathing, collapse, seizures or severe pain can make any situation an emergency. Ask the clinic rather than relying only on this category.
- Ask what else could explain the signs, which tests would change the plan and how discomfort will be managed. Symptoms alone cannot confirm this condition.
- Before going home, agree what to monitor, when to recheck and which signs mean calling sooner. Follow the individual treatment plan; do not copy another pet's prescription.
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Sources on this topic
Pages on this specific subject from recognised organisations. They are cited for further reading and do not mean the organisation has reviewed this page.
- Leptospirosis in dogs — American Veterinary Medical Association
- Leptospirosis in Animals — U.S. Centers for Disease Control and Prevention
Guidance libraries and further reading
These organisations publish relevant guidance. Their links are further reading, not evidence that they have reviewed this page.