Could dogs be at the origin of a new flu?

The results of a 10-year study suggest that two influenza strains could mix and form a new dangerous strain of influenza transmitted by dogs.

Dr. Daesub Song, Associate Professor (University of Korea, Republic of Korea) called for closer monitoring of dogs and other pets as they could be a source of new strains of human influenza. "Until now, dogs were considered neglected hosts in the field of influenza research.However, after the first report of an interspecific transmission, surveillance of influenza viruses from Pets should be further enhanced.

In the 2000s, several cases of viruses crossing the host barrier were recorded. The H3N2 bird flu virus has mostly affected dogs and has turned into canine influenza virus (CIV). Dr. Song's research has shown that this C3 H3N2 could combine with the H1N1 / 2009 virus and form a new influenza virus called CIVmv.

The emergence of new flu species like this one is worrying. Infected people will never have been in contact with a virus like this before, which means they would not be immune to the disease. If the virus could be transported and transmitted to humans by pets, it could potentially spread extremely quickly across the entire population.

The H1N1 / 2009 flu is known to have triggered the 2009-2010 global "swine flu" pandemic. When this strain of influenza combines with the CIV in dogs, some viruses recombine to form the CIVmv. Although the CIVmv is very similar to the CIV, the researchers calculated that the risk of spread of the disease to humans was much higher because of its high rate of infection in the ferret.

The viruses bind to host cells and cause infection via sialic acid (SA) receptors, which differ from one species to another. Ferrets have SA receptors very similar to humans. For this reason, ferrets are considered the most reliable experimental model for predicting and badessing the risk of new human influenza viruses.

During their studies on the new strain CIVmv, Dr. Song noted that infected dogs and ferrets exhibited typical symptoms of respiratory conditions, including congestion, difficulty breathing, coughing, streaming eyes, sneezing, lethargy and loss of appetite. In addition to these symptoms, Dr. Song reported that the new strain spreads faster in ferrets than other influenza viruses and replicates rapidly.

The researchers are trying to develop a vaccine against the virus. However, because of the high number of mutations, vaccines are very difficult to develop.

Despite the name of the dog flu virus, it is not only the dogs that can be infected with the CIV. During the ten-year study, researchers discovered that cats were also susceptible to the virus. Dr. Song investigated an outbreak of VIC in an animal shelter, where 100% of the cats were infected and 40% died.

The development of sensitivity in cats is worrying as it shows that CIV can spread among different animal species. Researchers have expressed concern that the virus may become endemic in pets. As dogs and cats are frequently in contact with humans, far more often than pigs or chickens, the potential risk that a new strain will grow and infect humans is even higher.

Since it was first identified in South Korea, CIV has expanded to China, Thailand and the United States. A case of CIVmv infection was identified in a dog in 2012 as a result of an H1N1 outbreak. Dr. Song used this strain in the ferret to determine if it was likely to be transmitted from canines to humans. From there, a new strain of human influenza could emerge. Dr. Song said, "Pre-existing IVCs can recombine or re-badort with human influenza viruses and give rise to new viruses that could in turn lead to unique pandemics."

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