No, that’s not a typo, I’m talking about H3N8, or Dog Flu. The Dog Flu is a mutation of the equine flu virus that’s affected horses for over 40 years. The virus appears to have made the jump to dogs about five years ago, at greyhound racing facilities in Florida. From there, the virus spread to other facilities in other states including Alabama, Texas, Arkansas, West Virginia, Kansas, Arizona, Iowa, Colorado, Rhode Island, and Massachusetts. The American Veterinary Medical Association reports in October 2009 that the virus has become endemic (very prevalent) in Florida, Colorado, and New York City; and Pittsburgh may be on its way. The virus had been found in 30 states (and Washington DC). A June 2009 New York Times article reported that an estimated 10,000 dogs have been infected (the total dog population in the United States is around 70 million). To date, there have been no confirmed cases in Minnesota. So far, this virus poses no threat to humans and appears to be relatively mild when transmitted to an otherwise healthy dog.
Transmission
H3N8 can be transmitted from dog to dog by touching noses or sharing a water dish with an infected dog. The virus can live on surfaces for up to 48 hours. Virtually 100% of dogs that are exposed become infected since there is no natural immunity for this new pathogen, making highly concentrated dog populations (boarding kennels, dog shows, dog parks, and dog daycares) a good conduit for transmission. Approximately 80% of dogs develop symptoms and 20% remain asymptomatic but can still transmit the disease. The incubation period is two to four days from exposure and dogs are also most contagious during this time. Dogs may remain contagious for up to ten days after infection (or six to eight days after onset of symptoms).
Symptoms
Symptoms of H3N8 are almost identical to Bordetella (Kennel Cough) and include: persistent cough that resists cough suppressants or antibiotics, nose and eye discharge, fever (the normal temperature for an adult dog is 100 to 102.5), loss of appetite, weakness and lethargy. The majority of dogs diagnosed with the flu have mild cases that are resolved on their own. A minority of cases progress to more severe pneumonia, and of those a few will result in death. There’s approximately a 5% mortality rate. It has been most deadly in dogs with existing medical conditions, and brachycephalics (Pugs, Shi Tzus, and Pekingese), dogs whose airways are bent and have difficulty breathing under normal conditions.
The Flu Vaccine
The H3N8 Flu vaccine was granted a provisional license in May 2009 by the USDA. It doesn’t prevent dogs from becoming infected, but reduces the symptoms and the period of time the dog is contagious, similar to the human seasonal flu vaccines. The vaccine is not recommended for every dog, it’s classified as a “lifestyle” vaccine. If your dog receives the Bordetella vaccine, he may be a good candidate for the flu vaccine because the risk groups are similar.
Treatment
So what can you do if you suspect your dog has been infected? First, contact your veterinarian and follow his/her instructions. Since this is such a highly infectious disease, keep him at home and away from other dogs at least during the initial two to four day incubation period and monitor for the afore-mentioned flu-like symptoms to develop. The AVMA recommends sick or exposed dogs be isolated for two full weeks to avoid spreading the disease. Your vet can perform tests to confirm whether or not he has the flu. There is no cure for the flu, treatment is largely supportive, meaning the dog is made as comfortable as possible so his body can fight off the disease. Supportive measures may include boosting the immune system, administering a bactericidal antimicrobial for mucus buildup and discharge due to secondary infection, and IV fluid intake to keep the dog hydrated. Most dogs recover within 2 to 3 weeks.
In addition to treating the dog, you should clean all surfaces your dog came in contact with using a bleach solution and wash your own hands with soap and water after touching your dog. The virus can live on hands for up to 24 hours.
For more information about H3N8, review the sources used for this post or contact your veterinarian to find out what they recommend.
American Veterinary Medical Association: http://www.avma.org/public_health/influenza/canine_bgnd.asp
New York Times: http://www.nytimes.com/2009/06/30/health/30flu.html?_r=2&ref=science
Key Facts about Canine Influenza: http://www.cdc.gov/flu/canine/
