Beware of dogs

A new study has shown that the influenza virus can jump from pigs to canines, and dogs are a potential reservoir for a future influenza pandemic. The study has been published in a recent issue of the journal “mBio”.

“The majority of pandemics have been associated with pigs as an intermediate host between avian viruses and human hosts. In this study, we identified influenza viruses jumping from pigs into dogs,” said study investigator Adolfo García-Sastre of the Centre for Research on Influenza Pathogenesis (CRIP), Icahn School of Medicine, New York.

Influenza can jump among animal reservoirs where many different strains are located; these reservoirs serve as mixing bowls for the genetic diversity of strains. When different strains of viruses harboured by animals swap genes and mix in animal reservoirs and jump to humans as a new strain, pandemic influenza can occur. Birds and pigs are major reservoirs of viral genetic diversity.

“In our study, what we have found is another set of viruses that come from swine that are originally avian in origin, and now they are jumping into dogs and have been reassorted with other viruses in dogs. We now have H1N1, H3N2, and H3N8 in dogs. They are starting to interact with each other,” said García-Sastre.

In this new study, the researchers sequenced the complete genomes of 16 influenza viruses obtained from dogs in Guangxi autonomous region, South China, during 2013-2015. They found that the genomes contained segments from genetic lineages derived from the above three infections.

In addition, the swine-origin H1N1 viruses were transmitted onward in canines and reassorted with the CIV-H3N2 viruses that circulate endemically in Asian dogs, producing three novel reassortant CIV genotypes (H1N1r, /H1N2r, and H3N2r).