Leptospirosis
A bacterial infection spread through contaminated water; can cause kidney and liver failure.
What is Leptospirosis?
Leptospira bacteria are shed in the urine of wildlife (rodents, raccoons, deer) and survive in standing water and moist soil. Dogs are infected by drinking, swimming in, or wading through contaminated water. Lepto is also zoonotic — it can spread to people.
Common signs and symptoms
Signs vary between dogs and can be subtle at first. Watch for the following, especially if several appear together or persist for more than a few days:
- Sudden fever and lethargy
- Vomiting and reduced appetite
- Increased thirst and urination, then decreased urination
- Jaundice
- Muscle pain, reluctance to move
- Coughing or difficulty breathing
Risk factors
Certain dogs are more predisposed. Understanding risk helps you screen earlier and act sooner.
- Access to standing water, puddles, streams
- Rural or wildlife-heavy environments
- Not just large dogs — small breeds are equally susceptible
When to see a vet
Use this as general triage guidance, not a substitute for veterinary advice.
- Book a routine appointment if: annual leptospirosis vaccination is recommended for most dogs. The old assumption that small breeds don't need it is outdated.
- Seek urgent care if: sudden vomiting, jaundice, and lethargy warrant same-day evaluation.
Diagnosis and management
Diagnosis uses PCR testing on blood and urine plus antibody titres. Treatment includes IV fluids, doxycycline, and often intensive supportive care. Modern 4-serovar vaccines are safe and effective.