Leptospirosis is a bacterial infection that can infect dogs and cause serious damage to the kidneys and liver – it is potentially fatal. It can also infect humans where it causes the condition known as Weil’s disease. There are different strains of leptospirosis and each causes a slightly different pattern of disease. Thankfully, a vaccination is available for dogs to protect them from the strains present in the UK – a booster must be given annually to maintain immunity.