The Lepto vaccine prevents against Leptospirosis. Leptospirosis is a bacteria that is spread from the urine of other infected animals. It is carried by wildlife and can become an issue when wildlife comes into your backyard. The bacteria is able to survive in the environment in standing water or soil for long periods of time. Pets contract this bacteria from drinking leptospirosis infected standing water or broken skin coming into contact with the bacteria. This bacteria can seriously affect the kidneys and liver, and can also be fatal. This bacteria can actually be passed to humans as well. We recommend vaccinating your pet yearly for this bacteria. If you received a Distemper vaccine from us, it does protect your dog from this bacteria for 1 year. If you were vaccinated elsewhere or was given a 3 year distemper shot, your dog may not be protected. 3 year distemper shots may include leptospirosis, but studies show that leptospirosis needs to be revaccinated yearly so if your dog had a 3 year distemper vaccine, you should still booster leptospirosis once a year. Your dog may not have been vaccinated against this bacteria because some breeders say it is too risky to give due to a very small portion of dogs having vaccine reactions. We are able to pretreat high risk dogs to make the possibility of vaccine reactions even smaller. We feel the risk of getting this potential deadly bacteria is higher than the risk of vaccine reactions. If you are unsure if your dog is protected or have more questions, please our office for more information.