Yes, several contagious illnesses circulate among dogs year-round, and respiratory viruses in particular have been spreading in waves across the United States. Canine influenza (H3N2) has caused sustained outbreaks in multiple regions since 2022, and the familiar cluster of pathogens behind “kennel cough” remains common wherever dogs gather in groups. Parvovirus also continues to pose a serious threat, especially to puppies and unvaccinated dogs.
Canine Influenza Is Still Circulating
The H3N2 strain of canine influenza has been the dominant dog flu virus in the U.S. for several years. A large outbreak in Los Angeles County in 2021 infected an estimated tens of thousands of dogs, with 1,344 confirmed cases. A second wave began around mid-2022 in the Dallas/Fort Worth area and then spread to many other parts of the country. More recent clusters in late 2023 and early 2024 were centered around Las Vegas. These outbreaks tend to follow a “boom and bust” pattern, flaring up in one region and then dying down before popping up elsewhere.
Dog flu spreads through respiratory droplets, so any place where dogs are in close contact is a hotspot. Most dogs recover on their own, but the virus can cause high fevers, persistent cough, and nasal discharge. A small percentage develop pneumonia.
Kennel Cough and Respiratory Infections
Canine infectious respiratory disease complex, commonly called kennel cough, is not caused by a single virus. It involves a mix of viruses and bacteria that attack the airways together. A dog can pick up one pathogen or several at once, and coinfections tend to produce worse symptoms.
In mild cases, you’ll see a dry, honking cough, some sneezing, and a runny nose. This typically clears up within one to two weeks without intensive treatment. But some dogs progress quickly. Within 24 to 48 hours of the first cough, a case can escalate to severe pneumonia with lethargy, loss of appetite, fever, and a wet, productive cough. Dogs with multiple infections at once or weakened immune systems are most vulnerable to this rapid decline.
Parvovirus Remains a Serious Threat
Parvovirus isn’t new, but it never stops circulating and it’s one of the deadliest viruses a dog can catch. It attacks the gut lining and causes severe bloody diarrhea, vomiting, and rapid dehydration. Puppies under 12 months old are hit hardest, particularly those that haven’t completed their full vaccination series. A 2023 outbreak among working dogs in Kazakhstan killed over 100 juveniles and even some vaccinated adults, illustrating how devastating the virus can be in group housing settings.
Parvovirus is extraordinarily tough outside the body. It can survive for months on surfaces, floors, grass, and soil, even through winter. Most household cleaners won’t kill it. A solution of one part bleach to roughly 30 parts water is the standard recommendation for disinfecting bowls, bedding, and indoor areas where an infected dog has been. The virus does lose some of its infectiousness after about a month indoors, but outdoors it can persist much longer.
A New Treatment for Parvo
A monoclonal antibody treatment for parvovirus has shown striking results in clinical trials and has moved through the USDA licensing process. In a controlled study, every dog that received the treatment survived, compared to 57% mortality in the untreated group. Treated dogs also had shorter bouts of diarrhea, vomiting, and fever, and their appetites and energy returned significantly faster. The treatment was tested safely in pet dogs ranging from 3 weeks to 15 years old. It’s designed to be used alongside standard supportive care (IV fluids, anti-nausea medication), not as a replacement for it.
Where Dogs Are Most Likely to Get Sick
Respiratory viruses spread through the air, so risk rises wherever dogs share enclosed or crowded spaces. Boarding kennels, doggy daycares, shelters, grooming salons, group training classes, and dog parks are the highest-risk environments. Even group dog walks raise the odds. If your dog regularly spends time in any of these settings, they’re what veterinarians consider a “social dog,” and their exposure risk is meaningfully higher than a dog that mostly stays home.
This doesn’t mean you need to keep your dog isolated. It means these are the situations where vaccination matters most and where you should pay attention to whether a facility requires proof of vaccination, separates visibly sick animals, and maintains good ventilation and cleaning protocols.
Symptoms That Need Attention
A mild cough that comes and goes for a few days isn’t unusual, especially after a boarding stay or a busy weekend at the dog park. Most respiratory infections resolve on their own within a week or two. What you’re watching for is progression.
Take note if your dog develops any of the following: thick or colored nasal discharge, loss of interest in food, unusual tiredness, fever (a warm dry nose alone isn’t reliable, but overall sluggishness combined with other signs is telling), or a cough that’s getting worse rather than better. For parvovirus specifically, the hallmarks are sudden vomiting, watery or bloody diarrhea, and rapid loss of energy, especially in a young or unvaccinated dog.
A normal resting breathing rate for dogs is 12 to 30 breaths per minute. Signs of true respiratory distress include rapid open-mouth breathing, a bluish tinge to the gums or muzzle, visible abdominal effort with each breath, the head and neck stretched forward as if straining for air, or wheezing and whistling sounds. Weakness or collapse alongside any of these is an emergency.
How Vaccination Helps
Vaccines are the single most effective way to protect your dog from the viruses currently circulating. Core vaccines cover parvovirus, distemper, and adenovirus. These are recommended for every dog regardless of lifestyle. Noncore vaccines, including those for canine influenza and the Bordetella bacterium behind many kennel cough cases, are recommended based on your dog’s individual risk factors. A dog that’s boarded frequently or visits daycare has a strong case for the full panel.
Puppies are especially vulnerable because maternal antibodies (protection passed from the mother) fade over the first few months of life, leaving a gap before the puppy’s own vaccine-driven immunity fully kicks in. This is why the puppy vaccination series involves multiple doses spaced weeks apart. Until that series is complete, keeping young puppies away from high-traffic dog areas is the safest approach.
What Your Vet Can Test For
If your dog’s symptoms are severe or aren’t improving, veterinarians can run a respiratory PCR panel on a nasal or throat swab. This test checks for a broad range of pathogens in a single sample, including influenza viruses, distemper, parainfluenza, adenovirus, and several bacteria commonly involved in respiratory disease. Knowing the specific cause helps guide treatment, especially in distinguishing bacterial infections (which may respond to antibiotics) from purely viral ones (which won’t). For parvovirus, a separate rapid test on a fecal sample gives results within minutes at most clinics.