Was last year’s much-publicized canine influenza outbreak just media hype, or an emerging threat to canine health every dog owner should be paying attention to?
Unfortunately, this one isn’t hype. There really is a new strain of canine influenza virus (CIV), dubbed H3N2, in the U.S. While for most dogs it causes mild respiratory symptoms, it seems to be somewhat nastier and more contagious than its older viral cousin, CIV H3N8. Around 5 percent of the dogs who contract it will die from its complications.
The original canine influenza virus, H3N8, emerged on the veterinary scene in 2004 when it was identified as the cause of respiratory disease in racing greyhounds in Florida.
As the first influenza virus known to affect dogs, H3N8 captured the attention of human medicine researchers as well as veterinarians, but in terms of the day-to-day veterinary care of pet dogs, most dismissed it as just one more cause of what is commonly called kennel cough – more accurately called canine infectious respiratory disease complex – which is usually no more dangerous than the common cold in humans.
Later research suggested H3N8 was more serious than at first believed, but while those usually-mild respiratory infections sometimes turned into pneumonia, such complications were rare. A vaccine was eventually developed, and attention to the virus dwindled.
In March of 2015, however, Chicago veterinarians began to worry about a particularly devastating outbreak of canine respiratory infections that appeared to be centered around the city’s dog parks. The dogs’ symptoms were much more severe than they should have been, and some dogs died despite aggressive care. What was going on?
Researchers eventually identified the bug behind most of these cases as a strain of canine influenza previously found only in Asia. No one really knows how it arrived in Chicago, although in this age of jet travel, it’s an ocean-hop many human and animal diseases have been making more frequently.
At the 2016 NAVC Veterinary Conference in Orlando, Florida, boarded veterinary internal medicine specialist Dr. Katharine F. Lunn of the North Carolina State University College of Veterinary Medicine told attendees the virus is serious and requires awareness and caution, but panic isn’t necessary or helpful.
“Because this pathogen has only relatively recently emerged in the dog population there is little natural immunity,” she said. “When introduced into a group of susceptible dogs, CIV infection can spread rapidly and morbidity (illness) rates are typically high.”
Both strains of the virus are spread the same way, through the droplets released when affected dogs sneeze or cough. CIV can be transmitted through the air at a distance of several feet, as well as directly between dogs and on the surfaces of bowls, hands, clothing, and dog beds. Dr. Lunn said the virus can survive “up to 48 hours in the environment, up to 24 hours on clothes, and up to 12 hours on hands.”
Signs of CIV are similar to other respiratory infections, and include lethargy, not eating, coughing, and sneezing. There is no specific treatment unless a secondary bacterial infection or pneumonia develops, or the dog becomes otherwise seriously ill.
Dog owners need to be especially aware of a few problems associated with CIV prevention and diagnosis. Dogs can spread the virus to other dogs even before they themselves display symptoms, and Dr. Lunn said most dogs are “no longer infectious by 10 to 14 days after initial exposure.”
However, she said, the fact that they shed the virus so early on, often before their owners have sought veterinary attention, makes it difficult for veterinarians to diagnose the disease later during its course.
Can CIV be prevented? There are vaccines available for both strains of CIV, however, while vaccinated dogs may have less severe symptoms and shed less virus, the vaccine doesn’t prevent the disease.
The best protection is to be aware of increased reports of respiratory symptoms in dogs in your area, and avoid taking your dog around other dogs at those times. Keep your dog away from dogs who are sneezing or coughing, and avoid sharing bowls, toys, or bedding. And just like with human flu, Dr. Lunn said, dog owners and people who work with dogs should “wash their hands regularly while handling their own or other dogs.”