Can Humans Get the Dog Flu? Canine Influenza...
Can humans get the dog flu? Learn the science behind canine influenza transmission, symptoms in dogs, zoonotic risks, treatment costs.
Can Humans Get the Dog Flu? The Short Answer
Canine influenza — commonly called "dog flu" — is a highly contagious respiratory infection caused by Type A influenza viruses that specifically target dogs. The two known strains are H3N8 (first identified in U.S. greyhounds in 2004) and H3N2 (originally from Asia, detected in the U.S. during a 2015 Chicago outbreak). Both strains spread rapidly through kennels, dog parks, grooming facilities, and anywhere dogs congregate.
Here's the answer to the question on every dog owner's mind: No, there is currently no evidence that humans can contract canine influenza directly from dogs. According to the Centers for Disease Control and Prevention (CDC), no human infections with canine influenza viruses have ever been reported. The H3N8 and H3N2 strains that infect dogs are genetically distinct from human seasonal flu viruses, and they lack the molecular adaptations needed to bind to human respiratory cell receptors.
That said, influenza viruses are notoriously adept at mutation and reassortment. While the current risk is essentially zero, veterinary epidemiologists continue monitoring these viruses because pigs — which can be infected by both canine and human influenza strains — could theoretically serve as "mixing vessels" for new hybrid viruses. This is why surveillance matters, even when the immediate threat to humans is negligible.
What Is Canine Influenza in Dogs?
Canine influenza virus (CIV) is an orthomyxovirus that attacks the respiratory epithelium — the lining of the airways and lungs. The virus replicates in the cells of the trachea, bronchi, and bronchioles, causing cell death and inflammation. This damage compromises the mucociliary escalator (the lung's natural cleaning mechanism), making dogs vulnerable to secondary bacterial pneumonia.
The disease exists on a severity spectrum:
- Mild form (approximately 80% of cases): A self-limiting upper respiratory infection resembling kennel cough, with coughing, nasal discharge, and lethargy lasting 10–21 days.
- Severe form (approximately 20% of cases): Progresses to pneumonia with high fever (104–106°F / 40–41.1°C), difficulty breathing, and potentially life-threatening complications.
The mortality rate for canine influenza is relatively low — estimated at 1–5% according to the American Veterinary Medical Association (AVMA) — with deaths typically occurring in dogs that develop secondary pneumonia or have pre-existing health conditions. However, the morbidity rate (percentage of exposed dogs that become infected) is extremely high, approaching 80–100% among susceptible, unvaccinated dogs in close-contact settings.
Symptoms of Dog Flu: What to Watch For
Symptoms typically appear 2–5 days after exposure, though the incubation period can extend to 8 days. Importantly, dogs begin shedding the virus before showing any clinical signs — meaning your dog can be contagious while appearing perfectly healthy.
| Severity Level | Symptoms | Typical Onset |
|---|---|---|
| Early / Mild | Persistent dry or moist cough (lasting 10–21 days) Nasal discharge (clear to mucoid) Mild lethargy or reduced playfulness Sneezing Mild appetite decrease Low-grade fever (101–103°F / 38.3–39.4°C) | Days 2–4 post-exposure |
| Moderate | Productive cough with yellow-green sputum Thick, colored nasal discharge Noticeable exercise intolerance Moderate fever (103–104°F / 39.4–40°C) Reduced appetite Mild dehydration | Days 4–7 post-exposure |
| Severe (Pneumonia) | High fever (104–106°F / 40–41.1°C) Labored or rapid breathing (tachypnea) Bluish gums or tongue (cyanosis — oxygen deprivation) Complete appetite refusal Severe lethargy or collapse Coughing up blood (hemoptysis) Dehydration (skin tent test positive) | Days 5–10 post-exposure |
Risk Factors: Which Dogs Are Most Vulnerable?
While any dog can contract canine influenza, certain factors dramatically increase both exposure risk and the likelihood of severe disease:
- Environment: Dogs in boarding facilities, shelters, dog daycares, grooming salons, and dog shows face the highest exposure risk. Outbreaks in shelters can infect 100% of susceptible dogs within days.
- Age: Puppies under 6 months and senior dogs over 8 years have weaker immune responses, making them more likely to develop severe pneumonia.
- Breed Predisposition: Brachycephalic breeds (Bulldogs, Pugs, Boston Terriers, Shih Tzus, Boxers) face elevated risk due to their already-compromised airway anatomy. Any additional respiratory inflammation can be disproportionately dangerous. Dogs with pre-existing tracheal collapse (common in Yorkshire Terriers, Pomeranians, Chihuahuas) are also at higher risk.
- Immune Status: Dogs on immunosuppressive medications (corticosteroids, chemotherapy), those with Cushing's disease, diabetes, or other conditions affecting immune function are more vulnerable to severe disease.
- Vaccination Status: Unvaccinated dogs have no strain-specific protection. Even vaccinated dogs may experience milder symptoms rather than complete prevention.
- Weight: Overweight and obese dogs (Body Condition Score 7–9/9) have reduced respiratory reserve, making pneumonia more dangerous.
How Veterinarians Diagnose Canine Influenza
If you suspect your dog has canine influenza, your veterinarian will use a combination of clinical signs, exposure history, and laboratory testing to confirm the diagnosis. Here's what to expect during the diagnostic process:
Step 1: Clinical Examination & History
Your vet will perform a thorough physical exam, listening to lung sounds with a stethoscope (auscultation), checking temperature, assessing hydration status, and examining the throat and nasal passages. They'll ask about recent boarding, dog park visits, grooming appointments, or contact with coughing dogs.
Step 2: Diagnostic Testing
| Test | What It Detects | Accuracy | Cost Range | Turnaround |
|---|---|---|---|---|
| PCR Panel (Respiratory) | Viral RNA from nasal/pharyngeal swab — detects CIV, Bordetella, and other pathogens simultaneously | High sensitivity (95%+) when collected early (days 1–5 of illness) | $150–$300 | 1–3 days |
| Serology (Antibody Titers) | Immune response — requires paired samples 2–3 weeks apart to show rising antibody levels | Confirms recent infection; not useful for acute diagnosis | $80–$150 per sample | 5–7 days |
| Complete Blood Count (CBC) | White blood cell patterns indicating viral vs. bacterial infection | Supportive, not definitive | $75–$150 | Same day (in-house) |
| Thoracic Radiographs (X-rays) | Lung changes consistent with pneumonia — infiltrates, consolidation | Essential for staging severity | $200–$450 (2–3 views) | Same day |
| Pulse Oximetry | Blood oxygen saturation levels | Real-time assessment of respiratory compromise | Included in exam or $25–$50 | Immediate |
| Bacterial Culture & Sensitivity | Identifies secondary bacterial infections and effective antibiotics | Critical for pneumonia cases | $100–$200 | 3–5 days |
Total diagnostic cost range: For a straightforward mild case, expect $200–$400 in testing. For a severe pneumonia case requiring X-rays, blood work, and culture, diagnostic costs typically run $500–$900 before treatment begins.
Treatment Options and Success Rates
There is no antiviral medication specifically approved for canine influenza. Treatment is supportive — meaning the goal is to manage symptoms, prevent complications, and support the dog's immune system while it clears the virus. The approach varies significantly based on disease severity.
| Severity | Treatment Approach | Setting | Duration | Success Rate |
|---|---|---|---|---|
| Mild | Rest, hydration monitoring, cough suppressants (e.g., butorphanol or hydrocodone-based, prescribed by vet), isolation from other dogs | Home care with vet guidance | 10–21 days | 95%+ full recovery |
| Moderate | All mild treatments plus: broad-spectrum antibiotics for secondary bacterial infection (e.g., doxycycline 5 mg/kg twice daily or amoxicillin-clavulanate 13.75 mg/kg twice daily), nebulization therapy, anti-inflammatories | Home care with daily vet check-ins or brief hospitalization | 2–4 weeks | 90%+ full recovery |
| Severe (Pneumonia) | Hospitalization, IV fluids, oxygen therapy, IV antibiotics, nebulization with coupage (chest physiotherapy), nutritional support, continuous monitoring | Veterinary hospital / ICU | 5–14 days hospitalized, then 2–4 weeks recovery at home | 80–90% survival with aggressive treatment |
Important medication note: Never give your dog human cold or flu medications. Acetaminophen (Tylenol), ibuprofen (Advil), and many over-the-counter decongestants are toxic to dogs. Only administer medications specifically prescribed by your veterinarian for your dog's condition. Your vet will determine the correct dosage based on your dog's weight and health status.
Prognosis and Recovery Timeline
| Stage | Expected Recovery | Long-Term Effects | Survival Rate |
|---|---|---|---|
| Mild (upper respiratory only) | Full recovery in 2–3 weeks. Cough may persist for up to 21 days even with treatment. | Generally none. Some dogs develop a lingering sensitivity to respiratory irritants. | >99% |
| Moderate (with secondary infection) | 3–4 weeks to full recovery. Energy levels may remain reduced for 1–2 weeks after symptoms resolve. | Occasional chronic bronchitis in dogs with repeated respiratory infections. | 95–99% |
| Severe (pneumonia) | 4–8 weeks total recovery. Hospitalization typically 5–14 days, followed by weeks of restricted activity. | Possible permanent lung scarring (fibrosis). Increased susceptibility to future respiratory infections. Some dogs require long-term management. | 80–95% (with aggressive treatment); significantly lower without hospitalization |
| Critical (ARDS/sepsis) | Rare but possible. Requires intensive care for weeks. | Significant permanent lung damage likely. Reduced exercise tolerance long-term. | 40–60% even with ICU care |
Dogs that recover from canine influenza develop strain-specific immunity lasting at least 12–24 months, though this is not guaranteed to be lifelong or cross-protective against the other CIV strain.
Home Care and Isolation Protocols
If your dog is diagnosed with mild-to-moderate canine influenza and sent home for recovery, strict management is essential:
Isolation requirements:
- Isolate the infected dog from all other dogs for a minimum of 21 days from symptom onset — dogs shed the virus for 10–14 days after symptoms begin, and some shed for longer.
- Do not visit dog parks, pet stores, grooming facilities, or any location where other dogs may be present during isolation.
- If you have multiple dogs, separate food bowls, water bowls, toys, and bedding. The virus survives on hard surfaces for 24–48 hours and on clothing/hands for up to 12 hours.
- Wash hands thoroughly with soap and water after handling the infected dog before touching other animals.
- Disinfect shared surfaces with a diluted bleach solution (1 part bleach to 30 parts water) or a veterinary-grade disinfectant like Rescue™ (accelerated hydrogen peroxide).
Supportive home care:
- Humidification: Run a humidifier in the room where your dog rests, or bring your dog into the bathroom while you run a hot shower (steam therapy for 15–20 minutes, 2–3 times daily) to loosen respiratory secretions.
- Hydration: Offer fresh water frequently. Adding low-sodium chicken broth (onion-free, garlic-free) to water can encourage drinking. Monitor for dehydration by checking gum moisture and skin elasticity.
- Nutrition: Appetite may be reduced. Offer warmed, strongly-smelling foods (canned recovery diets like Hill's a/d or Royal Canin Recovery). Hand-feeding small amounts frequently is more effective than leaving large meals out.
- Coupage: Your vet may demonstrate chest physiotherapy — gently cupping your hands and patting the rib cage to loosen mucus. Perform this 3–4 times daily for 5 minutes after nebulization or steam therapy.
- Activity restriction: No strenuous exercise during recovery. Short, leashed bathroom breaks only. Gradually reintroduce activity over 1–2 weeks after symptoms fully resolve.
Treatment Costs: What to Budget For
| Scenario | Diagnostic Costs | Treatment Costs | Total Estimated Cost |
|---|---|---|---|
| Mild case (home care) | $150–$300 (exam + PCR) | $50–$150 (cough suppressant, follow-up call) | $200–$450 |
| Moderate case (antibiotics + monitoring) | $300–$500 (exam, PCR, CBC) | $150–$400 (antibiotics, recheck exam, medications) | $450–$900 |
| Severe case (hospitalization) | $500–$900 (exam, PCR, CBC, X-rays, culture) | $2,000–$6,000+ (hospitalization at $200–$500/day for 5–14 days, IV fluids, oxygen therapy, IV medications) | $2,500–$7,000+ |
| Critical case (ICU / emergency) | $700–$1,200 | $5,000–$12,000+ (ICU care, ventilator support if needed, extended hospitalization) | $5,700–$13,000+ |
These costs vary significantly by geographic region — urban veterinary hospitals in major metro areas typically charge 30–50% more than rural practices. Pet insurance with illness coverage can reimburse 70–90% of these costs depending on your plan, though pre-existing condition exclusions apply if your dog was previously diagnosed with respiratory disease.
Prevention: Vaccines and Biosecurity
Vaccination: Bivalent canine influenza vaccines (protecting against both H3N8 and H3N2) are available from major manufacturers including Zoetis (Vanguard® Influenza) and Merck Animal Health (Nobivax® Canine Flu Bivalent). The vaccination protocol requires:
- Initial dose: Can be administered to puppies as young as 6–8 weeks of age
- Booster: Second dose 2–4 weeks after the initial vaccination
- Annual revaccination: Single dose every 12 months for ongoing protection
- Cost: $25–$45 per dose at most veterinary clinics
The vaccine does not guarantee complete prevention of infection, but it significantly reduces symptom severity, viral shedding duration, and the risk of pneumonia. According to the Merck Veterinary Manual, vaccinated dogs that do become infected typically experience only mild symptoms.
Non-vaccine prevention strategies:
- Avoid high-density dog environments during known outbreaks in your area
- Choose boarding facilities and daycares that require CIV vaccination for all dogs
- Quarantine new dogs entering a multi-dog household for 14 days
- Wash hands and change clothing after visiting shelters, dog shows, or veterinary clinics before interacting with your own dogs
- Keep brachycephalic and immunocompromised dogs away from group settings during flu season
When to See the Vet: Emergency Red Flags
- Difficulty breathing — open-mouth breathing, exaggerated abdominal effort, nostril flaring, or extended neck posture
- Blue, purple, or gray gums/tongue (cyanosis) — indicates critically low blood oxygen
- Temperature above 104°F (40°C) — high fever can cause organ damage
- Complete refusal to eat or drink for more than 24 hours
- Severe lethargy — inability or unwillingness to stand, unresponsiveness
- Coughing up blood (hemoptysis)
- Respiratory rate above 40 breaths per minute at rest (count chest rises for 15 seconds, multiply by 4)
- Signs of dehydration — tacky/dry gums, skin that doesn't snap back when gently pinched
These symptoms indicate possible pneumonia or acute respiratory distress syndrome (ARDS) and require emergency intervention. Do not wait for a scheduled appointment — contact your nearest emergency veterinary hospital immediately.
For non-emergency symptoms (mild cough, slight nasal discharge, reduced energy), call your regular veterinarian during business hours to schedule an examination. Mention any recent boarding, grooming, or dog park visits so they can prioritize canine influenza in their differential diagnosis.
Frequently Asked Questions
Can humans get the dog flu from their pets?
No. According to the CDC, there have been zero documented cases of humans contracting canine influenza (H3N8 or H3N2) from dogs. The viruses are species-adapted and lack the ability to infect human cells. However, practice standard hygiene — wash hands after handling a sick dog, and avoid letting your dog lick your face while they're ill.
Can my dog catch the flu from me if I'm sick?
Human seasonal influenza viruses (H1N1, H3N2 human strains) are not known to infect dogs under normal circumstances. However, there is one documented instance of human-to-cat transmission of H1N1 during the 2009 pandemic, demonstrating that reverse zoonosis is theoretically possible. The practical risk of you giving your dog the flu is extremely low, but if you're ill, minimizing close face-to-face contact with your pet is a reasonable precaution.
Can cats get canine influenza?
Yes — the H3N2 strain has been shown to infect cats, though this is uncommon. During the 2015–2016 U.S. outbreak, a small number of cats in shelter environments tested positive for H3N2. Cats in households with infected dogs should be monitored for respiratory symptoms and separated from the sick dog if possible. There is currently no feline-approved CIV vaccine.
How long is a dog with canine influenza contagious?
Dogs begin shedding the virus 24–48 hours before showing symptoms and continue shedding for approximately 10–14 days after symptom onset. The H3N2 strain may have a longer shedding period — some dogs shed intermittently for up to 24–26 days. This is why a 21-day isolation period is the minimum recommendation, with some veterinarians recommending 28 days for H3N2 cases.
What is the life expectancy of a dog after recovering from canine influenza?
Dogs that recover fully from mild or moderate canine influenza typically have a normal life expectancy with no lasting effects. Dogs that survive severe pneumonia may have some degree of permanent lung scarring that could slightly reduce exercise tolerance or increase susceptibility to future respiratory infections, but this rarely impacts overall lifespan significantly. Dogs that develop ARDS (acute respiratory distress syndrome) and survive may have more significant long-term respiratory compromise requiring ongoing management.
Is the canine influenza vaccine required?
The CIV vaccine is classified as a "non-core" or "lifestyle" vaccine by the AAHA (American Animal Hospital Association) canine vaccination guidelines. This means it's recommended based on your dog's risk profile rather than universally required. If your dog is regularly boarded, attends daycare, visits groomers, or participates in dog sports, vaccination is strongly recommended. Many boarding facilities now require proof of CIV vaccination as a condition of entry.
This article is for informational purposes only and does not replace professional veterinary advice. Always consult your veterinarian for diagnosis and treatment of any canine health condition. If you suspect your dog has been exposed to a toxic substance, contact the ASPCA Animal Poison Control Center at (888) 426-4435 (24/7, consultation fee applies).
Tom Renshaw
All our authors care for dogs every day — read more of their work on the authors page.
