People are concerned that the next human flu pandemic may be transmitted by their best friends – dogs. Read on for more dog flu facts and info.
A recent publication in the journal mBio reveals that the types of flu that can infect dogs is becoming more varied. This evolution of different strains can possibly eventually mutate to be able to infect humans, similar to the swine flu H1N1 pandemic of 2009, which killed more than 18,000 people (up to possibly an estimated 284,500 people, as revealed by research conducted in 2012 concerning actual numbers of fatalities).
There are two subtypes of influenza A that cause dog flu: H3N2 and H3N8. The canine influenza H3N8 viruses originated in horses and then spread to dogs. The first recognized case of canine influenza in the world was in 2004 when a greyhound at a Texas racetrack tested positive for H3N8 – it seems that the virus infected a horse and then mutated, having a chance to jump across species to infect dogs. Outbreaks of the H3N2 strain had been reported in Korea, China and Thailand, but only appeared in Chicago around 2015. That strain of influenza virus jumped from birds to dogs and is currently running rampant among dogs in New York City. Researchers have found that the virus is also capable of jumping from birds to pigs, and now from pigs to dogs.
We know that the virus can now jump from other animals to dogs, so it is only a matter of time before the virus adapts and evolves again to spread to humans.
Currently, dogs are able to catch influenza from humans, even though they may not show signs of infection. This is where the trouble stems from, since a major pathway of influenza evolution is when two different strains infect the same host. This would allow the virus to swap genes and adapt to infect the other species. To date, however, there has not been a single case yet of dogs spreading the flu to humans. To read more about the way dog flu has changed over the years, click here: American Council On Science and Health. However, the pattern of transmission into dogs is very similar to the lead up of the swine flu outbreak that occurred in 2009, experts warn.
The new flu strains recently identified in southern China have given researchers cause for concern. As flu strains become more diverse in canines, the risk that they can evolve to eventually infect humans becomes greater.
An excerpt from the publication states the importance of the discovery of increased diversity in canine flu strains:
IMPORTANCE Mammals have emerged as critically underrecognized sources of influenza virus diversity, including pigs that were the source of the 2009 pandemic and bats and bovines that harbor highly divergent viral lineages. Here, we identify two reassortant IAVs that recently host switched from swine to canines in southern China, including one virus with known zoonotic potential. Three additional genotypes were generated via reassortment events in canine hosts, demonstrating the capacity of dogs to serve as “mixing vessels.” The continued expansion of IAV diversity in canines with high human contact rates requires enhanced surveillance and ongoing evaluation of emerging pandemic threats.
While the H3N8 strain has not currently been seen to be transmissible from dogs to other species, the H3N2 influenza flu has indeed been reported to have jumped species from dogs to cats, guinea pigs and even ferrets.
With the increased diversity in dogs themselves, the types of combinations of viruses that can evolve in dogs represent a potential risk for genetic re-assortment and subsequent transference from dogs to humans – although this is unlikely to happen soon, it is extremely possible to occur in the not-so-distant future.
How infectious is the Dog Flu between Dogs?
Canine Influenza spreads easily between dogs and is incredibly infectious, with a study by the American Veterinary Medical Association stating that nearly all dogs who are exposed to it will become infected, with nearly 89% exhibiting outward symptoms of the illness. Dogs tend to get infected when housed in kennels and shelters. The flu is spread through coughing and sneezing from other infected dogs, or through contact with contaminated surfaces, according to the Centers for Disease Control and Prevention (CDC). There are vaccines available to protect your dogs from both the H3N8 and H3N2 canine flu strains – contact your vet for information.
Does my dog have the Dog Flu?
There are common symptoms, as listed below, but not all dogs show signs of illness. Severe illness can result in pneumonia, which can be fatal, but the fatality rate is low. Most dogs recover in 2 – 3 weeks:
- Cough
- Runny Nose
- Fever
- Lethargy
- Eye Discharge
- Reduced Appetite
- Labored Breathing
Diagnosis can be tricky, since the dog flu can sometimes mimic symptoms of kennel cough or other illnesses. To be sure, you should take your dog to see your vet for a medical exam.
Quick Recap:
- 2 subtypes of influenza A that cause dog flu: H3N2 and H3N8
- H3N8 originated in horses
- H3N2 had avian origins
- Dogs can catch the flu from humans, but humans, as yet, cannot catch it from dogs
- Dogs can infect cats, ferrets and guinea pigs with the flu
- Canine Influenza is highly contagious between dogs, and spreads easily in kennels and shelters
- There are vaccines available in some countries for the dog flu
- Common symptoms in the dog are cough, runny nose, fever and eye discharge
- As the flu virus continues to evolve and mutate, it keeps jumping to different species
- Given the current pattern, it is foreseeable that the virus can eventually spread from dogs to humans, similar to the swine flu pandemic of 2009
