Leptospirosis is a potentially fatal bacterial disease in dogs transmitted through contaminated water and rodent urine, and vaccination against the prevalent serovars is a critical welfare preventive measure.
Leptospirosis causes acute, severe welfare suffering — dogs with kidney and liver failure are acutely ill, jaundiced, and in organ failure that is distressing and painful without aggressive treatment. The disease can progress rapidly from mild signs to life-threatening organ failure within days, leaving limited time for intervention. Vaccination with the L4 vaccine is highly effective at preventing the most prevalent serovars responsible for UK clinical disease. Annual boosters are required because immunity wanes over 12 months — this is one of the core vaccines for which booster compliance is directly linked to welfare protection. Dogs in high-risk environments (rural areas, dogs that swim) should be specifically assessed for appropriate leptospirosis vaccination.