Leptospirosis is a bacterial disease which can affect many animals; it is a zoonotic disease, meaning it can be passed from animals to humans so it is vitally important that dogs are vaccinated to prevent infection and spread. It is caused by a particularly nasty group of bacteria of which there are several strains.
The bacteria can thrive in warm, humid areas and are often found in stagnant water (e.g. ponds). Dogs with a higher potential for exposure to contaminated water and wild animals are at a greater risk (e.g. rural areas, farm and hunting dogs). Adult dogs, males and large breed dogs appear to have a higher rate of infection; however, any dog can be exposed, since town wildlife such as rodents may also carry the bacteria.
The new L4 vaccine protects against four of the most common strains of the disease which is double the protection of the old L2 vaccine - this is great news for your pets!