Dog flu, commonly known as canine influenza (CI), is a highly contagious viral infection that affects both dogs and cats. Orthomyxoviridae is the family of influenza viruses. Hemagglutinin (HA) and neuraminidase, two unique proteins found in the lipid outer layer of the capsid, are used to further identify canine influenza as a Type A influenza virus (NA). There are currently two canine influenza virus strains known in the US: H3N8 and H3N2.
The influenza virus has the ability to rapidly alter and produce new strains that can infect other species. Both canine influenza variants found in the U.S. have links to influenza strains that are known to affect animals outside dogs. These viruses eventually developed the capacity to infect canines and spread from canine to canine.
Florida’s racing greyhounds were the first canine H3N8 influenza cases to be discovered in 2004. This strain is believed to have originated from an H3N8 equine influenza strain that spread from horses to dogs. Canine H3N8 influenza has been found in dogs in the majority of U.S. states and the District of Columbia since it was first discovered in 2004.
Following a dog respiratory sickness outbreak in the Chicago region in March 2015, canine H3N2 influenza was first discovered in the country. Prior to this, only South Korea, China, and Thailand have reported cases of the canine H3N2 influenza virus. It was first discovered in dogs in Asia in 2006–2007 and most likely developed as a result of an avian influenza virus being directly transferred to dogs—possibly from one of the viruses prevalent in live bird markets.
Additional instances of canine H3N2 influenza were identified in a number of states after the original diagnosis in Chicago. Early in 2016, H3N2 canine influenza was found in several shelter cats in Indiana. It is thought that sick dogs infected them with the virus.
Dogs in Florida, Georgia, North Carolina, South Carolina, Texas, Kentucky, Tennessee, Missouri, Louisiana, and Illinois were found to have canine H3N2 influenza in May 2017. The 2015 Chicago outbreak of H3N2 was caused by this strain.
There is no proof that either canine influenza strain (H3N8 or H3N2) may spread to people.
Droplets or aerosols containing respiratory secretions from coughing, barking, and sneezing are used to spread canine influenza. Dogs who come into touch with sick dogs frequently, such as at kennels, groomers, daycare centres, and animal shelters, are more likely to contract the disease. Indirect transmission of canine influenza can occur through kennels, food and water bowls, collars, and leashes, as well as through individuals who have come into touch with infected dogs. To prevent spreading the virus to other canines, it is crucial to clean and disinfect items that have come into touch with an infected animal. In order to prevent the virus from spreading, persons who have come into touch with an infected dog should wash their hands and change out of any contaminated clothing.
The virus can live and spread infection for up to 48 hours on surfaces, 24 hours on garments, and 12 hours on hands. To lower the danger of disease transmission, biosecurity controls and disinfection practises must be used.
The incubation period for H3N8 is 1 to 5 days, with the majority of cases seeing the onset of clinical indications 2 to 3 days after exposure. H3N2-infected dogs may begin exhibiting respiratory symptoms 2 to 8 days after infection. Dogs shed the virus even when they are not exhibiting any clinical symptoms of sickness, although they are most contagious during the incubation phase. Although some dogs may not exhibit symptoms of sickness, they may still be infected and shed the virus.
Pathology and clinical signs
From the nasal lining through the terminal airways, the canine influenza virus (CIV) infects and replicates within the cells of the respiratory tract. Rhinitis, tracheitis, bronchitis, and bronchiolitis are brought on by the inflammatory reaction to the infection. The respiratory tract’s epithelial cells die as a result of the pathologic process, exposing the basement membrane beneath. This increases the risk of subsequent bacterial infections in the respiratory system, which can cause coughing and nasal discharge.
Almost all canines exposed to the canine influenza virus get the disease, with about 80% showing clinical symptoms. 20% of infected dogs may not show any clinical symptoms, yet they can still shed the virus and infect others.
Canine influenza virus produces an acute respiratory infection in dogs, just like other mammalian influenza viruses. Canine influenza has no “season,” and infections can happen at any time of the year. Canine infectious tracheobronchitis, sometimes known as “kennel cough,” is a condition that affects dogs and is frequently caused by the parainfluenza virus and bordetella bronchiseptica.
The mild type of canine influenza is seen in the majority of sick canines. A cough that lasts for 10 to 21 days despite being treated with antibiotics and cough suppressants is the most typical clinical symptom. A mild, wet cough or a dry cough resembling kennel cough may be present in affected dogs. Lethargy, sneezing, nasal and/or ocular discharge, as well as anorexia, may also be seen. Many dogs get a fever and purulent nasal discharge (104-105oF). Secondary bacterial infections, like Pasteurella multocida and mycoplasma species, are frequently to blame for the nasal discharge.
Some canines experience more severe symptoms and display clinical indicators of pneumonia, such as a high-grade temperature (104 to 106 degrees Fahrenheit) and an accelerated pace of breathing. Lung lobe consolidation may be seen on chest x-rays during thoracic radiography. Although the majority of dogs recover without incident, H3N2 has been recorded to cause mortality in dogs.
Symptoms of upper respiratory illness in cats with H3N2 infection include nasal discharge, congestion, lethargy, lip-smacking, and excessive salivation.
Due to the fact that these clinical indications (coughing, sneezing, and nasal discharge) can occur with other canine respiratory disorders, canine influenza cannot be identified only by these clinical signs. There are tests available to diagnose and distinguish between canine influenza virus strains. Virus isolation, immunoassays to detect virus antigen, PCR to identify virus nucleic acid, and serology to check for virus-specific antibodies are some of the tests available. The most accurate test for canine influenza diagnosis may be the PCR. For advice on tests and sample collection, get in touch with your diagnostic lab.
To choose the best course of therapy and the available options, a veterinarian is needed. Like the majority of viral infections, canine influenza is mostly treated with supportive care. Healthy care and nutrition may aid in the immune system of dogs. Canine influenza usually clears up in dogs within two to three weeks. Additional diagnoses and treatments, such as but not limited to: may be required due to secondary bacterial infections, pneumonia, dehydration, or other health conditions (such as pregnancy, pre-existing lung disease, immunosuppression, tracheal collapse, etc.).
- Antimicrobials for secondary bacterial infections that are known or suspected.
- As needed, nonsteroidal anti-inflammatory drugs can be used to treat inflammation and fever.
- fluids to prevent dehydration or keep you hydrated.
Treatment adjustments should be made as necessary, taking into account the patient’s response to the treatment, other health factors, and other aspects including the owner or caretaker’s compliance and capacity for caring for animals.
Canine H3N2 influenza-infected canines should be kept apart for 4 weeks from other dogs in the home in order to avoid the spread of the virus.
Only human use of antiviral medications is permitted for the treatment of influenza. Their application, effectiveness, and safety in dogs are poorly understood. The federal extralabel drug use laws of the Animal Medicinal Treatment Use Clarification Act must be followed by veterinarians who use approved pharmaceuticals in a manner that does not correspond with approved label directions (for example, using an antiviral drug exclusively permitted for use in humans) (AMDUCA).
Morbidity and mortality
The canine influenza virus is not common among dogs and many of them have never been exposed to it. The percentage of exposed animals who become ill is believed to reach 80%. Less than 10% of people in the population really die. Most dogs with the severe version of the sickness pass away.
Canine influenza-infected cats have not yet been documented to have died.
Prevention and control
The canine influenza virus can survive on hands and clothing for up to 24 hours and can stay viable in the air for around 2 days. The canine influenza virus appears to be easily eliminated in veterinary, boarding, and shelter facilities by disinfectants often found there, like quaternary ammonium compounds (like benzalkonium chloride), aldehydes, potassium peroxymonosulfate, phenols, and bleach (1:30 dilution) solutions. It is necessary to create cleaning and disinfection procedures to lessen the possibility of viral transmission from indirect contact with people or other pests (e.g. cages, bowls, exam rooms, etc.).
Each and every worker needs to wash their hands with soap and water:
- Upon entering the building
- touching each dog both before and after
- when exposed to a dog’s saliva, urine, excrement, or blood
- after cage cleaning
- Prior to taking breaks, having meals, or leaving the building
- prior to and following bathroom use
When a dog exhibits clinical symptoms of a respiratory ailment, strict isolation practises should be followed. Before the isolation time is through, dogs who have been exposed to canine influenza (CI) or who are displaying respiratory symptoms shouldn’t be brought to places where other dogs are present, such as training sessions, dog shows or events, daycare centres, and boarding and shelter facilities.
Dogs who are ill or exposed need to be kept alone, ideally in a space with its own air supply. Four weeks of solitude are suggested. When handling sick animals, put on personal protective equipment (a gown and gloves at the very least) to prevent contaminating clothing. After coming into contact with dogs exhibiting respiratory disease symptoms, thoroughly clean and sanitise all clothing (including shoes), tools, surfaces, and hands. To prevent exposing their dogs to the virus, owners of dogs who are coughing or displaying other symptoms of respiratory disease should refrain from engaging in activities with other dogs or bringing their canines to places where other dogs are present.
Biosecurity measures should be put in place at veterinary clinics to stop the spread of canine influenza among the clinic’s canines. Dogs exhibiting clinical symptoms of a respiratory condition shouldn’t be allowed in the waiting area. Until clinic personnel is prepared to see the dog without running the danger of exposing other dogs, clients may need to wait in their car with their dog. Dogs suspected of having the flu should enter and exit the building by a different door and stay away from the main entrance. After the dog is discharged, any locations where potentially contaminated canines are evaluated and treated, as well as any tools used, must be meticulously cleaned and disinfected. When inspecting or treating dogs suspected of having canine influenza, staff personnel should put on personal protective equipment (at the very least, gloves and a gown).
There are vaccines for both the H3N8 and H3N2 strains of canine influenza. There is also a bivalent vaccine that provides defence against both strains. Cats cannot currently use canine influenza vaccinations that have been licenced for use in dogs. Canine influenza can be prevented in dogs with vaccination. Although vaccination may not completely prevent an infection, it may lessen the intensity and length of clinical sickness.
Since it is a “lifestyle” vaccine, not every dog should receive the canine influenza vaccine. Generally speaking, the vaccination is meant to protect dogs who are at danger of coming into contact with the canine influenza virus, such as those who participate in activities with lots of other dogs or who are housed in communal spaces, especially in areas where the virus is common. Given that the risk groups are comparable, dogs who have had the kennel cough (Bordetella/parainfluenza) immunisation may benefit from the canine influenza vaccine. To ascertain their dog’s risk of coming into contact with the canine influenza virus and whether vaccination is acceptable for their dog, dog owners should speak with their veterinarian.
What is the name of the canine influenza vaccine?
Immunization is Crucial for Protection Effective prophylaxis is the greatest form of canine influenza treatment. It has been demonstrated that Nobivac Canine Flu Bivalent is effective against canine influenza virus strains H3N2 and H3N8.
How long is the dog flu vaccine effective?
As advised, having a conversation with your veterinarian about influenza vaccine is warranted, especially in the aforementioned higher risk groups. Due to the significant amount of time and effort needed to thoroughly sanitise and quarantine canines visiting their facilities as well as the potential for significant financial loss, operators of boarding and daycare facilities may also mandate vaccination of dogs visiting their facilities. Generally speaking, dogs that attend gatherings and engage in social activities should have all of their core vaccinations, as well as Bordetella and canine influenza shots.
It’s best to give your dog an annual flu shot, just like you would. Dogs should have two initial rounds of immunizations, followed by a yearly booster, to be fully protected against influenza.
How does canine influenza infect dogs?
The canine flu virus can infect almost any dog, and canines living in kennels and shelters are more likely to contract it. The major ways that canine flu is known to be transmitted are through contact with contaminated surfaces or respiratory droplets produced by sick dogs’ coughing and sneezing. Dog owners should avoid exposing their pets to other dogs or cats if their canines are coughing or exhibiting other symptoms of a respiratory illness. After handling dogs exhibiting respiratory disease symptoms, it is advisable to clean and disinfect any exposed clothing, tools, surfaces, and hands.
Is there a test for canine influenza?
It is possible to test dogs for infection with the H3N8 and H3N2 canine influenza viruses. If testing is necessary, your veterinarian can advise you.
How is canine influenza in dogs treated?
The majority of the time, supportive care is used to keep the dog comfortable and hydrated while its body produces an immune response to the infection to speed recovery. If your dog has a milder version of the condition, this care can involve fluids to keep him hydrated and medication to make him more comfortable. If a secondary bacterial infection is thought to be present, your veterinarian can recommend broad range antibiotics.
Is there a vaccine for canine influenza?
In the US, vaccines against both H3N8 and H3N2 canine influenza are available for dogs. If you have questions regarding these shots or if you should consider giving your dog a vaccination, ask your veterinarian.
My dog has a cough. What should I do?
If an appointment is required, speak with your vet to ascertain whether it is necessary so they may examine your dog and make a treatment recommendation.
Which canines require the canine influenza vaccine?
Be his advocate if your dog needs to go to a boarding, grooming, or daycare facility. Make that the staff at these institutions is properly trained to recognise cross contamination and how to prevent it, that they adhere to a tight cleaning schedule and regimen, and that they use suitable disinfection solutions. Finding a facility that mandates vaccination of all dogs before to admission will also help to protect your dog.
Dogs who are more likely to be exposed should receive vaccinations. Since the H3N8 strain of the canine influenza virus was the only one at the time it was discovered in the United States, the first canine influenza vaccination was released in June 2009 to help prevent infection. Following the Chicago pandemic, Merck Animal Health declared in 2015 that an H3N2 vaccination was now available. It was advised that high-risk canines should be immunised against both strains of the virus now that both have been found in the U.S. because the incidence of one strain or the other is unpredictable.
A vaccination was introduced in October to help prevent infection with both virus types. Healthy canines seven weeks of age and older can receive the vaccine, which needs to be administered twice with two to four weeks in between each shot. According to preliminary research, dogs’ immunity does not last for a very long time, so it is crucial to revaccinate them every year.
Despite the fact that the dog flu has been reported in 40 states (including Washington, DC), not all high-risk facilities have made the vaccination mandatory. Typically, only individuals who have reported flu instances in their company or city feel forced to demand it. Due to this, some veterinarians do not have the vaccine on hand. If you’ve chosen to immunise your dog against the canine flu, be sure to let your vet know so they can place an order for you if they don’t typically keep it in stock. The vaccination should be given to your dog at least two weeks before any potential exposure in order to guarantee that it will provide full protection.
However, it is important for parents to recognise that vaccinated dogs CAN still contract the disease and become afflicted. The vaccination’s goal is to stop the disease from spreading by lessening the intensity and length of the sickness and its symptoms, as well as the quantity and duration of virus that afflicted dogs sweat.
Please speak with your veterinarian if you have any additional questions regarding dog flu, doubt whether your dog is at danger, or wonder whether your pet should have the vaccination. They will assist you in choosing the most effective defence for your best companion!
Charlie has worked in the veterinary business for more than 18 years, 14 of those as a technician who has earned a board certification. She earned an Associate of Science in Veterinary Technology with honours from Harcum College and was a member of Phi Theta Kappa.