Leptospirosis is a potentially fatal bacterial disease in dogs transmitted through contaminated water, with vaccination and avoiding high-risk environments providing the most effective welfare protection.
Leptospirosis causes profound acute welfare harm through rapid multi-organ failure. The pulmonary haemorrhage syndrome (LPHS) that can develop in severe cases causes catastrophic lung bleeding — affected dogs deteriorate from mild respiratory distress to haemorrhagic shock within hours. Even dogs that survive with intensive care often face weeks of hospital treatment including IV fluid diuresis, antimicrobials, and supportive management of liver and kidney failure. The welfare burden of hospitalisation for a severe leptospirosis case — days to weeks of catheterisation, IV lines, restricted movement, and unfamiliar environments — is substantial and entirely preventable through vaccination. Annual vaccination with L4 covers the four most clinically significant serovars in the UK and Europe, and the protective efficacy is excellent. High-risk activities — swimming in river water, farm visits, rat-infested premises — should be avoided or the vaccination status verified and current before exposure. Prompt antibiotic treatment (doxycycline) in early-stage disease before organ failure significantly improves welfare outcomes.