When you go for your dog's annual checkup, chances are your vet has talked to you about the leptospirosis vaccine.

Leptospirosis (or lepto) is a disease caused by an infection with bacteria that are spread by the urine of an infected animal and can be found in water or soil. The bacteria can survive there for weeks, according to the Centers for Disease Control and Prevention. Wild animals can spread the disease and then dogs can pick it up through an open cut or when drinking from an infected water source.

Rats can also be common carriers of the disease, so lepto can be found in large urban areas where rodents are a problem. They might transmit the disease after drinking in a puddle or leaving droppings on streets or in kennels where dogs are housed.

The disease is zoonotic, meaning it can be spread from animals to people. The disease isn't very common, but it is serious.

"It's not simple to get leptospirosis but if you're a dog and you get it, you're really sick and you could die," veterinarian Lori Bierbrier, D.V.M, a medical director at the ASPCA, tells MNN. "And on top of that it can then be transmitted to a person. It’s a pretty big deal all around."

Without treatment, lepto can cause a slew of serious human health problems, including liver failure, kidney damage, meningitis, respiratory issues and can eventually lead to death.

Lepto symptoms and treatment

Lepto can cause serious damage to a dog's liver and kidneys, according to the American Veterinary Medical Association. Symptoms can include fever, vomiting, diarrhea, dehydration, muscle tenderness, increased thirst and lethargy. Because those are some of the same symptoms seen in many other conditions, a vet will typically base a diagnosis on exposure history as well as diagnostic tools such as blood tests, urine tests, X-rays and ultrasounds.

Lepto is typically treated with antibiotics but often can require a long hospital stay. The outlook can be positive for the pet if the disease is caught early, but there's still the chance of permanent liver or kidney damage.

If your dog is diagnosed with lepto, there are key steps you have to take to keep yourself and your family safe. Avoid contact with your dog's urine and if you have to clean up a spill, be sure to wear rubber gloves. Wash your hands after handling your pet and try to keep your dog from urinating in any standing water that other animals might come in contact with.

(Little is known about lepto in cats, although it is rare and appears to be very mild, according to the AVMA.)

Preventing lepto

dog walking in city If your dog isn't the rugged outdoorsy type, he may not need the lepto vaccine. (Photo: Anna Jurkovska/Shutterstock)

There is a leptospirosis vaccination that is targeted toward several strains of the bacteria that can cause the disease. It's kind of like the flu vaccine, Bierbrier says, where it protects against some of the more common strains that are circulating, but doesn't guarantee protection against the illness.

"The vaccine isn't perfect," she says. "It can be a little bit of a false sense of security that you are protected when you're not."

One common sense precaution you can take to keep your pet safe is to always carry drinking water for your pet, Bierbrier suggests. That will keep him from drinking out of puddles or streams or any other place where water can be infected with lepto bacteria.

Talk to your veterinarian to discuss whether your dog is a good candidate for the vaccine. Your animal's location and lifestyle are the two factors to consider. If you have a pet that is almost always indoors, walks on sidewalks, and isn't playing in woods or in rivers or streams, he may not need the vaccine. However, if your dog is an outdoorsy type or you live somewhere where rats are an issue, it may be worth getting the vaccine.

Active dogs that come in contact with water and wildlife are at the top of the list for the vaccine, says Kwane Stewart, D.V.M., chief veterinarian officer with American Humane.

"If you have a dog that you take out occasionally hiking, that probably warrants a lepto vaccine, but if you have a small breed dog that you just walk in your neighborhood, that probably wouldn’t," Stewart says.

He evaluates every dog on a case by case basis, also taking into consideration that some dogs have reactions to the vaccine. Your vet can dig into your dog's history and lifestyle — like does your dog mostly keep to city streets but you take him hiking in the wilderness for a week every year — which can help make the decision about whether to vaccinate or not.

"It's really still a rare disease. In my 20 years of practice, I've diagnosed it maybe six times out of thousands and thousands of animals," Stewart says. "We don't want to scare people. We just want them to be aware."

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.