Leptospirosis is a bacterial disease transmitted through contaminated water that causes severe kidney and liver disease in dogs and is also a significant zoonosis.
Leptospirosis causes severe, rapid-onset illness that is distressing and often fatal without intensive treatment. The disease is expanding geographically as flooding events increase, bringing dogs into contact with contaminated floodwater. Vaccination provides important protection but requires annual boosters and coverage of locally relevant serovars — vaccine formulations vary in serovar coverage. Dogs that swim in stagnant water, live in or near rural areas with wildlife or livestock, and those with flood water exposure are at highest risk. Post-flood assessment of leptospirosis risk and preventive veterinary care is important welfare management.