Dog Leptospirosis: Vaccination, Welfare, and Zoonotic Risk

Leptospirosis is a potentially fatal bacterial disease of dogs transmitted through infected water and urine, for which vaccination is highly effective and protects both dog welfare and human health.

Key Facts

Leptospirosis is caused by Leptospira bacteria carried by rodents, cattle, wildlife, and infected dogs.
Dogs are infected through contact with contaminated water, soil, or urine — particularly in flooded environments.
Clinical signs range from mild lethargy to severe acute kidney and liver failure with high mortality.
Leptospirosis is a zoonotic disease — infected dogs can transmit the bacteria to human family members.
Vaccination with quadrivalent vaccines protecting against four serovars is recommended annually in endemic areas.
Treatment requires intensive care including IV fluids, antibiotics (doxycycline or penicillin), and organ support.
Climate change and increasing flood events are expanding the geographic range of leptospirosis in many regions.

Welfare Considerations

Leptospirosis causes acute and severe suffering — affected dogs experience kidney pain, vomiting, jaundice, and in severe cases haemorrhage and death. The disease progresses rapidly, and animals that are not treated within hours to days of severe signs face very poor prognoses. The zoonotic dimension creates additional pressure — infected dogs living with vulnerable family members (immunocompromised individuals, young children) represent a genuine public health concern. Annual vaccination is the most effective intervention for both dog welfare and public health, and is particularly important in areas with high rodent populations, standing water, or flood risk.

What You Can Do

Ensure dogs receive annual leptospirosis vaccination, especially in endemic or high-risk areas.
Avoid allowing dogs to drink from stagnant water sources or swim in potentially contaminated water.
Seek immediate veterinary care if dogs show signs of acute kidney or liver disease following water exposure.
Wear gloves when handling urine or body fluids from potentially infected dogs to prevent zoonotic transmission.