Leptospirosis is a bacterial infection dogs pick up from water and soil carrying wildlife urine. Autumn rain refills every puddle and ditch, so this is its season. The early signs are frustratingly ordinary: low energy, poor appetite, vomiting, sore muscles. Because it can shut down the kidneys within days, it is one illness where waiting until morning matters.
Why we talk about it from September onward
Leptospira bacteria do not survive long in hot, dry conditions. They survive very well in what the Lower Mainland gets from mid-September: mild temperatures, steady rain and shallow water that sits still for days.
The other half is wildlife. Rats, mice, raccoons, skunks and squirrels carry these bacteria without looking unwell and shed them in urine. Rain washes that into puddles, ditches, long grass and the low corner of a back yard. A dog drinks it, or wades through it and licks their paws afterward. It also gets in through the soft tissue around the eyes, nose and mouth, and through a cut or a graze, so a dog does not have to swallow anything for this to happen.
Autumn concentrates rodents too. As the weather turns they move toward sheds, garages, compost heaps and houses, which puts them in exactly the places dogs sniff.
The early signs look like nothing much
This is why leptospirosis reaches us late. For the first day or two an affected dog is simply off:
- Low energy, or reluctance to go for the usual walk
- Eating less, or refusing food outright
- Vomiting, sometimes with diarrhea
- Fever, shivering, or a dog who feels warm and looks miserable
- Stiffness, a hunched posture, or apparent muscle soreness
- Drinking noticeably more, or passing much more or much less urine than normal
- Yellowing of the gums, the whites of the eyes or the skin inside the ears
- Reluctance to be touched over the back or belly
The change in drinking and urinating is the one owners most often dismiss and the one that matters most. Any dog that suddenly empties the water bowl, asks to go out repeatedly, or stops producing urine altogether needs to be seen that day, not the next.
Yellow gums, a dog who will not stand, or one who has stopped urinating are reasons to come in overnight rather than wait for a morning appointment.
Why it becomes an emergency
Leptospira target the kidneys and the liver. Damage can develop quickly and it can be permanent. Some dogs recover fully with prompt care, some are left with lasting kidney changes, and a proportion do not survive it.
Two things improve the odds more than anything else. The first is being seen early, before a dog has spent three days getting quietly worse at home. The second is telling us about the water. A history of puddle drinking, ditch wading, a muddy trail or a rat problem in the garage changes what we look for and how fast we look for it, so please volunteer it even when it feels irrelevant.
Assessment through our medical services starts with hydration, temperature, abdominal pain and gum colour. Blood and urine testing through our pet diagnostics shows what the kidneys and liver are doing, and those numbers are what tell us whether a dog goes home tonight or stays on fluids.
The part that concerns your family
Leptospirosis is zoonotic, meaning it can pass from animals to people. That is not a reason for alarm, but it is a reason for sensible hygiene while a dog is unwell and being investigated.
- Wash your hands after handling your dog, their bedding, their bowls or their waste
- Wear gloves to clean up urine, and do not hose it around as a spray
- Keep children away from puddles of your dog’s urine
- Tell us if anyone at home is pregnant, elderly or has a weakened immune system
Lowering the risk before the wet season settles in
- Bring water with you. A dog who leaves home with a full bowl and drinks from a bottle on the walk is far less interested in a ditch. This is the single most effective habit.
- Teach a reliable leave. Worth the training time when every path has standing water on it.
- Choose the route. Gravel and mown grass over flooded field edges and slow ditch water, particularly after heavy rain.
- Rinse and dry after muddy walks, which removes what your dog would otherwise lick off.
- Deal with standing water at home. Tip out buckets, wheelbarrows, plant saucers and paddling pools, and refresh outdoor bowls daily rather than topping them up.
- Make the property less attractive to rodents. Secure bins, lift fallen fruit, store feed in sealed containers, and keep woodpiles away from where the dog sleeps.
- Ask your own veterinarian about vaccination. A leptospirosis vaccine exists, and current North American guidance now points toward it for most dogs rather than only the ones with an outdoor lifestyle. Whether it suits yours is still a conversation worth having properly, so raise it at the next visit.
Cats, and the rest of the household
Cats are exposed too but rarely become unwell from it, so this is mostly a dog conversation. The wildlife that spreads it is a broader issue, and the same rodents and raccoons bring other problems with them. Our guide to raccoon and wildlife encounters covers the injuries that come from the animals themselves.
When to come to us rather than wait
Our emergency care runs overnight through the week, from 4 PM on Saturdays, and 24 hours on Sundays and holidays, which covers exactly the hours when a dog who was quiet at suppertime becomes properly unwell by midnight.
Come in tonight for: repeated vomiting, a dog who cannot keep water down, yellow gums or eyes, no urine production, collapse or extreme weakness, or a dog with a fever who was in or near standing water in the past two weeks. Phone us on the way so we are ready.
Frequently asked questions
My dog drinks from puddles all the time and has never been ill. Is this overblown?
Most puddle drinks cause nothing at all. The point is that it is a repeated, avoidable exposure across a long wet season, and the consequences when it does go wrong are severe rather than inconvenient. Carrying water costs nothing and removes most of the risk.
How soon after exposure would my dog seem unwell?
Usually within about a week, though it can be longer. That gap is exactly why this gets missed, so mention any ditch, slough or flooded field from the previous couple of weeks even if it seems unconnected to how your dog is today.
Does the vaccine make my dog safe?
No vaccine makes any animal completely safe. It covers the strains most commonly seen and substantially reduces risk, but it does not replace sensible avoidance of standing water. Think of it as one layer alongside the habits above.
Can my other dog catch it?
It can spread between dogs through urine, so tell us if you have others at home. We will talk you through cleaning, separation while a dog is being investigated, and whether the others need checking.
The ditch near me looks clean. Does that mean the water is safe?
Clear water tells you nothing useful. Leptospira are microscopic and the water carrying them often looks perfectly ordinary. Judge by whether the water is still or slow moving and whether wildlife can reach it.
My dog is just a bit quiet and off his food. Is that enough to come in?
In autumn, after a wet walk, yes. A quiet dog who is off his food for a day is worth a phone call. Most turn out to be something minor, and the ones that are not benefit enormously from being seen early.
Speak to the team at Mainland Emergency Animal Clinic
If your dog is unwell after being anywhere near standing water, phone us and tell us about the water.
Published by the team at Mainland Emergency Animal Clinic.
This article is for general educational purposes only and is not a substitute for an in-person veterinary examination or advice about your individual pet. If you have an urgent concern about your pet, contact Mainland Emergency Animal Clinic right away.
Mainland Emergency Animal Clinic
15338 Fraser Highway, Surrey, BC V3R 3P5
Phone: (604) 588-4000
Email: mainlandanimalemerg@gmail.com
Hours: Monday to Friday 5:00 PM to 8:00 AM; Saturday 4:00 PM to 8:00 AM; Sunday and holidays 24 hours