You’re not the only one who needs to head to the clinic this flu season; your dog might need to pay a visit as well! Yes, dogs can fall victim to the influenza virus just like humans, pigs, birds, and other animals.
There are specific strains that exist among dogs, but they could pass to humans in the future, experts say. To ward off a potentially dangerous “dog flu,” scientists from the University of Rochester introduce a new type of live-attenuated flu vaccine.
A live-attenuated vaccine contains a weakened virus that, while still alive, triggers an immune response without actually causing illness. On the other hand, inactivated vaccines contain no live virus, only pieces of it that trigger a response. Historically, most live-attenuated vaccines have been the measles/mumps/rubella combined vaccine, chickenpox vaccine, and human influenza vaccine. Polio and hepatitis A are prevented with an inactivated vaccine.
Two new studies, led by scientist Luis Martinez-Sobrido, PhD, resulted in two of the first-ever live-attenuated vaccines for canine influenza, specifically for a strain called H3N8. Veterinarians have used inactivated vaccines for canine flu in the past, but the recent study results suggest that the live-attenuated vaccines are more effective and still very safe. Currently, the H3N8 strain is circulating in dogs in the United States.
Both studies used a genetic engineering technique called reverse genetics, a relatively new approach that, as its name suggests, works in the opposite direction of what many scientists would call “traditional” genetics. Instead of starting with a mutant phenotype and working toward identifying its DNA and protein sequence, a reverse genetics approach begins with recombinant DNA and works backward to identify a mutant phenotype.
The first of Martinez-Sobrido’s studies involved developing a live-attenuated vaccine that solely multiplied in the nose instead of in the lungs. This method was intended to “stop the virus in its tracks” once it made its first stop at the nose, allowing the immune system to wipe out the infection before it traveled to the rest of the body.
The second study removed an integral piece of the H3N8 canine influenza virus to obtain the desired effect of an immune response without the detrimental impact of an actual illness. The protein is called NS1, and past research led scientists to believe that separating it from the H3N8 strain would have this effect.
Both of the studies produced a vaccine candidate that proved to be safe and more effective than existing H3N8 vaccines, which researchers were able to show via tests in mice and in canine tracheal cells. As the research progresses, Martinez-Sobrido plans on beginning clinical trial with dogs, hoping that some day soon the new live-attenuated vaccine for this troublesome strain of canine influenza might be used on a larger level, starting with preventing the spread of disease in shelters and kennels.
The two studies were published in the Journal of Virology and the journal Virology.
Sources: BIO Ventures for Global Health, HistoryofVaccines.org, An Introduction to Genetic Analysis, 7th edition, University of Rochester Medical Center
