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Plan on your dog being contagious until the coughing and the runny nose have been gone for a full week. That's the answer I give at the front desk. Kennel cough isn't one illness though, it's a group of them, and one of the organisms involved can be carried for months after the dog looks completely better.
Key Takeaways
Call us the same day if your coughing dog goes off food, becomes lethargic, feels feverish, is breathing fast or hard at rest, has green or yellow nasal discharge, or is a puppy under six months. Kennel cough is usually mild, but it can progress to pneumonia, and puppies are the ones it happens to. Call us at (519) 896-0532.
For most dogs, shedding tracks with the illness. Clinical signs and shedding typically last 5 to 10 days.1 Once the cough and the discharge have stopped, the risk to other dogs falls off quickly.
Bordetella bronchiseptica is the exception, and it's the one the vaccine is named after. Bemis and colleagues followed a breeding kennel where pups were ill for one to two weeks and then kept shedding the organism for two to three months.2 They concluded that prolonged shedding was what kept the infection alive in that kennel.
So there are two honest answers depending on what you're asking. If you want to know when your dog stops being a meaningful risk to the dog at the park, that's about a week after signs resolve. If you want to know when he's biologically clear of Bordetella, that could be months, and there's no practical way to know without testing.
Every pathogen in this group also has a shedding period that starts before any signs appear, and incubation is usually 2 to 7 days.1 So by the time you hear the first cough, your dog has already been to daycare, met dogs on the walk, and shared the water bowl at the park.
Seven days after the last cough. Not seven days after starting treatment, and not seven days after you noticed he was improving. Seven clear days with no coughing, no gagging and no nasal or eye discharge.
I'd apply the same rule to daycare, the dog park, group training, and the neighbour's dog. If you board with us, that's what our boarding team will ask you about at check-in, and it's worth calling ahead rather than finding out at the door.
Seven days is a practical threshold, not a biological one. It's the point where risk has dropped far enough that normal dog life is reasonable again, given that a recovered Bordetella carrier could technically be shedding for weeks longer.2 Waiting three months isn't realistic, and nobody recommends it.
If you have another dog in the house, assume they've already been exposed. The useful work is limiting how much virus and bacteria they take on, and protecting dogs outside your home.
Kennel cough is a syndrome, not a single infection. The profession calls it canine infectious respiratory disease complex, or CIRDC, because more than a dozen organisms can produce the same cough, and dogs are often carrying several at once.
Which one your dog has determines how long he's a risk to other dogs, and whether the vaccine covered it at all.
| Pathogen | Shedding after recovery | In a standard vaccine? |
|---|---|---|
| Bordetella bronchiseptica (bacteria) | Up to 2 to 3 months2 | Yes. This is the kennel cough shot |
| Mycoplasma species (bacteria) | Can be prolonged1 | No |
| Canine parainfluenza | Usually within the 5 to 10 day illness1 | Yes. In DA2PP and most intranasal shots |
| Canine adenovirus-2 | Usually within the 5 to 10 day illness1 | Yes. The "A2" in DA2PP |
| Canine respiratory coronavirus | Usually within the 5 to 10 day illness1 | No |
| Canine herpesvirus-1 | Usually within the 5 to 10 day illness1 | No |
| Pneumovirus | Usually within the 5 to 10 day illness1 | No |
| Canine influenza (H3N2, H3N8) | Usually within the 5 to 10 day illness1 | Separate vaccine, not part of the routine set |
| Canine distemper | Can be prolonged1 | Yes. The "D" in DA2PP |
The classic presentation is a dog who is bright, eating, and otherwise completely well, with a harsh honking cough that comes in fits. Owners often describe it as something stuck in the throat.
What you'll typically see:
A dog with straightforward kennel cough still wants dinner and still wants a walk. If yours doesn't, that's the part worth calling about.
Most cases stay mild and self-limiting.1 The one that doesn't is bronchopneumonia, and it shows up most often in puppies and in older or debilitated dogs.6 Severe infection is more common in young and immunocompromised animals generally.1
Get in touch the same day if you see fever, lethargy, loss of appetite, fast or laboured breathing at rest, or nasal discharge that's turned thick and coloured. That combination is the trigger for a real workup rather than watchful waiting.
Coughing up blood is a separate conversation and never fits the kennel cough picture. If that's what you're seeing, read our piece on the most common causes of a dog coughing up blood and then call us.
Usually not. Most kennel cough is viral, so antibiotics often aren't indicated, and most dogs resolve on their own within about 10 days without them.3
The international guidelines are specific about this. Antimicrobial treatment should be considered inside that 10-day window only if there's fever, lethargy or loss of appetite together with mucopurulent discharge.3 When antibiotics are warranted, doxycycline for 7 to 10 days is the recommended first choice.3 Merck puts it the same way: antibiotics are usually not needed unless there's evidence of pneumonia.6
So antibiotics do shorten things in the cases that call for them, but they aren't a routine part of managing this, and reaching for them in a dog who's bright and eating doesn't help your dog or the next one. Supportive care is the mainstay: rest, a harness instead of a collar, and keeping the household calm enough that he isn't barking himself hoarse.1
The intranasal vaccine works fastest. In a challenge study, dogs vaccinated 72 hours before exposure had almost no clinical signs, while dogs vaccinated only 48 hours ahead weren't meaningfully different from unvaccinated controls.4 So three days is the number, and two isn't enough.
The injectable version is slower. AAHA advises against injectable Bordetella vaccines in high-density settings because of the delayed onset of immunity and the fact that they do little to stimulate local immunity in the upper airway, which makes them less effective at limiting disease than intranasal products.5 Injectable also needs a two-dose series, given 2 to 4 weeks apart, before you can count on it.5
If your dog is booked to board next week and isn't current, call us now rather than the day before. There's more detail in our guide to the Bordetella vaccine, and if you're weighing a reaction your dog had previously, our page on vaccine reactions in dogs covers what's normal and what isn't.
The kennel cough vaccine targets Bordetella, and often parainfluenza alongside it, because those are the ones worth vaccinating against. Bordetella is among the most contagious of the group and causes the most severe illness in an unvaccinated dog. Adenovirus-2, parainfluenza and distemper are covered separately in the DA2PP vaccine.
That still leaves Mycoplasma, respiratory coronavirus, herpesvirus and pneumovirus with no vaccine at all.
Coverage isn't the only limit. With the exception of distemper, vaccination against these organisms doesn't prevent colonization and shedding, and vaccinated dogs can still develop clinical signs.3 What the vaccine reliably does is reduce how sick your dog gets. We've written about why vaccinated dogs still catch kennel cough, because it's the question we field most often after a diagnosis.
Less time than most people assume. Most CIRDC pathogens survive in the environment no more than a few hours, in the case of distemper, to a few weeks for Bordetella, and they're inactivated by virtually all routinely used disinfectants.1
The exception is adenovirus-2. Like other non-enveloped viruses it resists many products, and reliably killing it takes household bleach at a 1:32 dilution, roughly half a cup per gallon, or a potassium peroxymonosulfate or accelerated hydrogen peroxide product.1
Follow the contact time on the label rather than spraying and wiping straight away, since that's the exposure the product was tested at. Then dry the surface, because lingering moisture extends how long these organisms survive.1
Hands, leashes, clothing and shared bowls move this between dogs over moderate distances. The leash you didn't wash is a more realistic route than the sidewalk.
Bordetella bronchiseptica occasionally infects people, mainly those with existing respiratory disease or a compromised immune system.1 For a healthy adult the risk is low, but if someone in your household is immunosuppressed or has ongoing lung disease, mention the dog's diagnosis to their physician.
Bordetella can also infect cats, and canine influenza H3N2 has been reported in cats too.1 Cats can carry it without looking sick and pass it back to dogs.1 If you have both species at home, keep the coughing dog separated from the cat for the same seven days.
If you're not sure whether what you're hearing is kennel cough, or your dog is due to board and you're worried about timing, give us a call at (519) 896-0532. It's a quick conversation and usually a quick exam.
Plan on seven days. Clinical signs and shedding usually last 5 to 10 days, and once the coughing and nasal discharge have stopped, the risk to other dogs drops sharply. Bordetella is the exception. In one closed kennel study, dogs were ill for one to two weeks but kept shedding the bacteria for two to three months afterwards. Waiting months isn't realistic, which is why seven clear days is the practical threshold most boarding facilities use.
Yes. Every pathogen in this group has a shedding period that begins before any signs appear, and incubation runs about 2 to 7 days for most of them. By the time you hear the first cough, your dog has usually already been out on walks, to daycare, or around other dogs. It's the main reason kennel cough spreads the way it does, and it's why nobody could have caught it earlier.
Usually not. Most kennel cough is viral, so antibiotics often aren't indicated, and most dogs recover on their own within about 10 days. International guidelines recommend considering antibiotics inside that window only if there's fever, lethargy or loss of appetite alongside thick coloured discharge. When they are warranted, doxycycline for 7 to 10 days is the first choice. A dog who is bright, eating and just coughing generally needs rest and supportive care, not a prescription.
A few hours up to a few weeks, depending on the organism, and virtually any routinely used disinfectant kills them. Canine adenovirus-2 is the exception and needs household bleach at roughly half a cup per gallon, or a potassium peroxymonosulfate or accelerated hydrogen peroxide product. Follow the contact time on the label rather than spraying and wiping immediately, and dry the surface afterwards, because moisture extends survival.
Bordetella bronchiseptica occasionally infects people, mainly those with existing respiratory disease or a weakened immune system. For a healthy adult the risk is low. Cats are a different story. Bordetella can infect cats, canine influenza H3N2 has been reported in them, and cats can carry it without appearing sick and pass it back to dogs. If you have both at home, keep them apart for the same seven days.
Yes. With the exception of distemper, vaccination against these organisms doesn't prevent colonization and shedding, and vaccinated dogs can still develop signs. What the vaccine reliably does is reduce how sick your dog gets. It also only covers some of the organisms involved. Mycoplasma, canine respiratory coronavirus, herpesvirus and pneumovirus have no vaccine at all, so a fully vaccinated dog can still pick one of those up.
Call the same day if your coughing dog goes off food, becomes lethargic, feels feverish, is breathing fast or hard at rest, has green or yellow nasal discharge, or is a puppy under six months old. Straightforward kennel cough leaves a dog bright, hungry and keen for a walk. When those things change, the concern is bronchopneumonia, which shows up most often in puppies and in older or debilitated dogs.
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