08/26/2022
CANINE INFLUENZA OUTBREAK IN MIDDLE TENNESSEE-- As many of you have likely heard, Canine Influenza is currently very prevalent in the middle TN region and surrounding states. Our local emergency hospitals are seeing and have seen several cases of confirmed Canine Influenza, Canine Distemper and Bordetella ("kennel cough")-- additional laboratory testing is needed to differentiate between these respiratory diseases. The canine patients the emergency hospitals are seeing have predominantly been type H3N2 and have been exposed usually in environments with large populations of other dogs (rescues, boarding facilities, animal shelters).
Canine Influenza is HIGHLY CONTAGIOUS but we are often able to treat the dog without hospitalizing it. Most dogs will exhibit a cough that can persist for 10-21 days despite being on antibiotics. Canine Influenza virus infection often resembles canine infectious tracheobronchitis ("kennel cough") which is caused by one or more bacterial and/or viral infections, including the bacteria Bordetella bronchiseptica and the parainfluenza virus. Due to the damage/cell death of respiratory tract epithelial cells caused by the Canine Influenza virus, secondary respiratory infections can occur.
If the dog's symptoms are worse than a hacking cough (not eating, elevated temperature, or increased respiratory rate), the dog may need to hospitalized in an isolation ward or in an oxygen cage at an emergency hospital.
Canine Influenza is transmitted by droplets or aerosols (respiratory secretions from coughing, barking or sneezing) and high risk areas include kennels, groomers, doggie daycare facilities and animal shelters. The virus can be transmitted indirectly through objects such as food and water bowls, collars and leashes, or even humans. Viruses can remain viable on surfaces up to 48 hours, on clothing for 24 hours, and on hands for 12 hours.
Dogs exposed to Canine Influenza often do not show clinical signs for 2-8 days after infection. Dogs are most contagious during the incubation period (1-5 days) when they may not exhibit clinical signs. Some dogs have subclinical infections but are still shedding the virus. Clinical signs of Canine Influenza are nasal and/or ocular discharge, sneezing, lethargy and anorexia may be observed. A soft, wet cough or a dry cough similar to that of "kennel cough" is usually heard. A cough can last 10-21 days. Many dogs develop a purulent (yellow to green) nasal discharge and fever (104-105*F). The nasal discharge is usually caused by a secondary bacterial infection such as Pasteurella multocida and mycoplasma species.
CATS CAN BE INFECTED WITH THE H3N2 CANINE INFLUENZA VIRUS. Cats often display signs of upper respiratory disease, including nasal discharge, congestion, malaise, lip smacking, and excessive salivation.
Presently, there is no dog to human transmission reported. However, keep in mind that the influenza virus can mutate, as the World Health Organization global surveillance system has led to the detection of human infections by novel influenza A viruses of animal origins (such as avian or swine influenza A viruses).
Treatment of influenza is supportive-- most dogs will recover in 2-3 weeks and often as outpatients. The mortality rate is less than 10% at this time but there have been reported deaths due to Canine Influenza. Secondary bacterial infections, pneumonia, dehydration, and other health factors (pregnancy, pre-existing pulmonary disease, immunosuppression, tracheal collapse, etc) may necessitate additional diagnostics and treatments including antibiotics, anti-inflammatories, fluid therapy, hospitalization, etc.
To prevent transmission of the virus, dogs infected with canine H3N2 influenza as well as other dogs in the household should be isolated for AT LEAST 4 WEEKS. This means not using communal potty areas, dog parks, walking trails, etc.
We strongly encourage dog owners to vaccinate their dogs for Canine Influenza. Due to the recent increase in cases, the vaccine has been difficult to get in due to backorders-- please check with your clinic about availability and recommendations in your area. For dogs that have never been vaccinated for Canine Influenza, they will receive the initial vaccine and then need a booster 2 weeks later. Just like human flu vaccines, the H3N2 CIV vaccine may not completely prevent infection but will make it less likely. Additionally, if a vaccinated dog does get infected, the disease is likely to be more mild and of shorter duration.
For more information about Canine Influenza:
https://hospitals.vetmed.ufl.edu/files/2017/05/Info-for-Pet-Owners-on-Canine-Influenza-1.pdf
https://www.avma.org/resources-tools/animal-health-and-welfare/canine-influenza
Canine influenza virus is caused by a highly contagious infection caused by an influenza A virus. The causative strains have been classified as H3N8 and H3N2.
