Leptospirosis is a bacterial disease dogs pick up from water and wet ground. It attacks the kidneys and liver, it can become life-threatening in a dog that isn’t protected, and it can spread from dogs to people.
We have diagnosed it in our own patients here at Caring Hands. The bacteria are still here, in the water and wet ground Montana dogs spend their days around.
Below is what leptospirosis is, how dogs in Montana come into contact with it, the signs worth knowing, what it means for your family, and how to protect your dog.
What Is Leptospirosis?
Leptospirosis is an infection caused by Leptospira bacteria, which are spread through the urine of infected animals. A dog catches it when that urine, or water and soil it has contaminated, gets into the mouth or eyes or through broken skin.
Once inside, the bacteria spread through the body. In dogs, the most common result is sudden kidney damage, and some dogs develop sudden liver failure as well. The illness ranges from mild enough to go unnoticed to severe disease involving several organs at once.
The bacteria can survive for long periods in standing and slow-moving water. That is why water is where most dogs meet them.
Why This Matters in Montana
Leptospirosis is more common in warm, wet climates than in ours, and that makes it easy to underestimate here. Freezing weather shortens how long the bacteria survive, so in Montana the risk runs highest in the wet, unfrozen months, from spring runoff through fall.
The state does track it. In its 2018 summary of reportable small-animal diseases, the Montana Department of Livestock listed leptospirosis at about 8 to 12 cases a year and noted it was being reported with increasing frequency. It is a reportable disease in people in Montana as well.
How a Montana dog actually comes into contact with it is worth walking through.
How Dogs Get Leptospirosis in Montana
Dogs get leptospirosis from the urine of infected animals, most often through water or wet ground where that urine has collected. In Montana, that means the places dogs naturally go: stock tanks, irrigation ditches, river backwaters, duck marshes, beaver ponds, and the low spot in the yard after a rain.
Wildlife are the main carriers. Montana Fish, Wildlife and Parks names rodents, beaver, deer, and raccoons as the wild species most commonly infected. Many of these animals carry the bacteria without becoming sick themselves, so there is rarely any warning at the water’s edge. Livestock carry it too, and cattle are among the domestic animals most often affected.
In practice, where a dog is exposed depends on how it spends its time.
- Bird and duck dogs retrieve from marshes and prairie potholes, drink whatever water is in the field, and can get into gut piles and carcasses. Eating infected tissue is its own route of infection.
- Ranch dogs drink from stock tanks and work around cattle, corrals, and calving, where contact with urine and birthing fluids comes with the job.
- River and lake dogs swim in and drink from slow-moving and still water, which the CDC lists as a common source.
- Town dogs drink from puddles and share their yards and alleys with raccoons and rodents.
Can My Dog Get Lepto From the Backyard?
Yes. A dog does not have to hunt, swim, or leave town to be exposed. Leptospirosis can live in something as ordinary as a backyard, carried in by the wildlife in your neighborhood. A raccoon crossing the yard overnight, mice along the fence line or under the deck, and a puddle where they pass are enough.
That is also why small dogs in town are not exempt. The current specialist consensus on leptospirosis notes that it still occurs in small-breed dogs from urban areas, not only in dogs that work outdoors.
Because exposure is this easy to miss, it helps to know what an infected dog looks like.
Early Signs of Leptospirosis in Dogs
The early signs of leptospirosis look like a dog that is simply under the weather: tiredness, poor appetite, fever, vomiting, and drinking and urinating more than usual. They usually appear about 2 to 14 days after exposure, and some infected dogs show no signs at all.
That is what makes it easy to miss. On their own, none of these signs points to leptospirosis. What should raise the question is the combination: a dog that seems off and has recently been around water, wet ground, livestock, or wildlife.
What to Watch For
- Tiredness, weakness, or sleeping more than usual
- Not eating, or eating less
- Fever
- Vomiting or diarrhea
- Drinking more water and urinating more often
- Stiffness, trembling, sore muscles, or reluctance to move
Call Us Right Away If You See
- Yellowing of the gums, skin, or whites of the eyes
- Very little urine, or none
- Blood in the vomit or stool
- Nosebleeds or bruising you can’t explain
- Coughing or labored breathing
These signs mean the kidneys, liver, or blood are involved, and they need a veterinarian the same day. If your dog shows the earlier signs after time around water or wildlife, call us that day rather than waiting to see if it passes. We are not a 24-hour hospital. After hours, call our main number first, and if no one is available, go to an emergency veterinary hospital.
When you call, tell us where your dog has been. A swim in a stock pond last week, or a raccoon in the yard, is exactly the history that points us toward testing for leptospirosis.
Leptospirosis is treatable, and how early it is caught matters.
Can Dogs Recover From Leptospirosis?
Yes. Many dogs recover from leptospirosis, and their chances are best when treatment starts early, before the kidneys and liver are badly damaged.
Confirming the diagnosis takes blood and urine testing, and sometimes a repeat test, because early results can come back negative in the first week of illness. Treatment is a course of antibiotics to clear the infection, plus care for the organs it has affected. Dogs with kidney or liver involvement are usually hospitalized for IV fluids and supportive care. The most severe cases may need dialysis at a specialty hospital to support the kidneys while they recover.
Recovery is not always complete. Some dogs that recover from a severe case are left with permanent kidney damage and need regular monitoring afterward.
This is not an illness to manage at home. It takes prescription antibiotics, lab work, and often hospital care. A dog that is not fully treated can keep shedding the bacteria in its urine for up to three months, which puts other pets and the people in the house at risk. If your dog is diagnosed, give every dose, even once they seem better.
That raises the next question: can people catch it from their dog?
Can People Catch Leptospirosis From Their Dog?
Yes, people can catch leptospirosis from an infected dog, although it does not pass easily between dogs and people. It reaches people the same way it reaches dogs, through contact with infected urine or with water and soil it has contaminated.
In people, leptospirosis most often causes no symptoms or a flu-like illness, but in a small share of cases it becomes serious. Montana’s public-health bulletin calls it an occupational hazard for people who work outdoors or with animals, farmers and veterinarians among them.
If Your Dog Is Diagnosed
A few precautions from the CDC protect everyone in the house while your dog is treated:
- Avoid contact with your dog’s urine, and wear gloves when you clean it up.
- Clean urine spots with an antibacterial cleaner, or a solution of 1 part household bleach to 10 parts water.
- Have your dog urinate in an area you can easily clean.
- Wash your hands after handling your dog, its bedding, or anything that might have urine on it.
- Give every dose of the prescribed medicine, and come back for the follow-up visit.
If you are concerned you have been exposed, call your own doctor and tell them your dog has leptospirosis. That detail helps them know what to look for.
The best way to keep any of this out of your house is to keep your dog from getting it in the first place.
Does My Dog Need the Lepto Vaccine?
At Caring Hands, yes. We recommend the leptospirosis vaccine for every dog, including small dogs that mostly stay indoors in town. It is one of our core vaccines for dogs, and the veterinary specialist consensus is that all dogs are at risk, whatever their breed, lifestyle, where they live, or the time of year.
Montana’s own public-health bulletin puts it plainly: for domestic animals, vaccination is the cornerstone of prevention.
It is tempting to skip a vaccine for a disease that seems rare. That gets the logic backwards. We see fewer cases in our patients because we vaccinate, and we still see cases.
How Often Does My Dog Need the Lepto Vaccine?
Our schedule is two doses, two to four weeks apart, to start, followed by a booster every year.
The booster is yearly because protection from the lepto vaccine is built to last about a year, not the longer stretch some other vaccines provide.
What About Vaccine Reactions?
Reactions to the lepto vaccine are uncommon, and when they happen they are usually mild: soreness where the shot was given, and sometimes swelling or tiredness in more sensitive dogs. Those are the same risks that come with any vaccine.
You may have heard that the lepto vaccine is hard on small dogs. We hear it most often from Dachshund owners. That reputation comes from some older lepto vaccines, which were linked to more allergic-type reactions. Today’s lepto vaccines are no more likely to cause a serious reaction than the distemper-parvo or rabies vaccines. Small dogs can be somewhat more prone to vaccine reactions of any kind, which is a reason to tell us about a past reaction, not a reason to go without protection.
If your dog has ever reacted to a vaccine, tell us. We note it in their record and plan ahead for the next booster, which can include an antihistamine we give here before the shot. Please don’t give your dog any medication at home without asking us first. If you notice anything unusual after any vaccine, call us. For more on how vaccines work in the background, see The Hidden Safety Net of Veterinary Vaccines.
Habits That Help
The vaccine is the strongest protection we have, and a few everyday habits add to it:
- Carry fresh water on hikes, hunts, and ranch work so your dog isn’t drinking from ponds, ditches, or puddles.
- Discourage drinking from standing water at home, and drain the spots where puddles collect.
- Keep rodents under control around the house, barn, and kennel.
- Keep your dog’s lepto booster on schedule.
Not sure whether your dog is current? Your dog’s vaccine history is in the Pet Portal, or call us and we will check for you.
Sources and Further Reading
- Leptospirosis in Dogs, Merck Veterinary Manual, Dog Owners edition
- Canine Leptospirosis, Cornell University College of Veterinary Medicine
- Leptospirosis in Dogs, American Veterinary Medical Association
- Leptospirosis in Animals, Centers for Disease Control and Prevention
- Sykes JE, Francey T, Schuller S, et al. Updated ACVIM Consensus Statement on Leptospirosis in Dogs. Journal of Veterinary Internal Medicine, 2023
- Leptospirosis, Montana Fish, Wildlife and Parks
- Montana One Health: Leptospirosis, Montana DPHHS and Department of Livestock, December 2018
- Stock Quotes Animal Health Newsletter, Montana Department of Livestock, December 2018
- Montana Reportable Disease List, Montana DPHHS, July 2024
Leptospirosis FAQs
Can cats get leptospirosis?
Cats can be infected, but they rarely get sick from it. Veterinary specialists consider cats far more resistant to the disease than dogs, and there is no approved leptospirosis vaccine for cats. If your cat shares a yard or barn with your dog, the same habits that protect your dog help.
Is leptospirosis contagious to other dogs?
It does not spread easily from dog to dog, but it can. An infected dog sheds the bacteria in its urine, so dogs that share space, such as at daycare or in a kennel, can be exposed. If one of your dogs is diagnosed, ask us about the others in your home.
Which animals spread leptospirosis in Montana?
Montana Fish, Wildlife and Parks names rodents, beaver, deer, and raccoons as the wild animals most commonly infected. Cattle and other livestock carry it too. Many carriers look perfectly healthy while shedding the bacteria in their urine.
Can my dog get lepto from eating deer poop?
Droppings are not the main way it spreads. Leptospirosis travels in urine. Deer leave both in the same places, though, and the water and wet ground around a pile are where the real risk sits. It is a habit worth discouraging either way.
Can my dog get lepto from cattle or a stock tank?
Yes. Cattle are among the domestic animals most often infected, and a stock tank collects water that animals drink from and stand around. Ranch dogs that drink from tanks or work around calving have regular exposure, which is one more reason to keep them vaccinated.
How often does my dog need the lepto booster?
Every year. Our schedule is two doses, two to four weeks apart, to start, followed by a booster every year.
Does my small or indoor dog need the lepto vaccine?
Yes. We recommend it for every dog, including small dogs that mostly stay indoors in town. Wildlife carry the bacteria into backyards, and leptospirosis still turns up in small-breed dogs from urban areas. Reactions are uncommon and usually mild, and if your dog has reacted to a vaccine before, tell us so we can plan ahead.
Can I treat leptospirosis at home?
No. Leptospirosis needs a veterinarian, lab testing to confirm it, and prescription antibiotics, and many dogs need hospital care. If you suspect it, call us the same day.
