If you're a dog owner, you're most likely aware that your canine companion needs an array of vaccines to remain healthy and immune from diseases. One especially dreaded canine sickness is the Canine Influenza Virus (CIV) which is contagious to other dogs and is caused by a specific Type A Influenza virus. A vaccine for CIV already exists to prevent one of the two subtypes of CIV, the H3N2, but scientists are continuous in their search for better canine immunization.
In two new studies, scientists were able to develop a temperature-sensitive vaccine for the H3N8 strain that's more effective than the current vaccine in the market. The only vaccine available in the market today is an inactivated influenza vaccine (IIV) which the scientists consider suboptimal and would require further steps to prevent CIV whereas the new live-attenuated canine influenza vaccine (LACIV) was observed to be more effective in its prevention of the virus.
Live Vaccine for a Live Virus
The study made by scientists from the University of Rochester School of Medicine and Dentistry that yielded such results came from one significant change in the current vaccine's composition. While the current commercial inactivated influenza vaccine (IIV) uses virus particles that have been cultured then killed in the laboratory, scientists opted to study the effects of keeping the virus alive, albeit reduced in virulence. What resulted was a live-attenuated canine influenza vaccine that is not just more effective, but provide better immune responses for longer periods of time.
Using reverse genetics techniques, scientists created a vaccine that efficiently replicates in canine cells at 33 degrees, but is impaired at 37-39degrees. Further, the live virus used by scientists in the experiment was dulled down to prevent the virus from causing the flu itself, and replicated right in the dog's nose to prevent virulent viruses from entering the lungs, causing serious complications. A second study by some of the same scientists as the first study got similar results for the LACIV, though the development was made by modifying NS1 protein in the vaccine. Either way, the development and effectiveness of the vaccines opens up immunization possibilities for canines susceptible to H3N8.
However, though the LACIV proved more effective against the H3N8 compared to the current vaccine in the market, results were less effective to the H3N2 strain of the virus, making scientists see the need for the further development of a new LACIV for the control and prevention of H3N2 CIV as well.
H3N2 and H3N8
Canine Influenza or 'dog flu' is a contagious respiratory disease known to infect dogs. The two subtypes of CIV currently known to scientists are H3N2 and H3N8, which differs mainly in the source of the virus before it adapted for canines. H3N2 adapted from the avian influenza, while H3N8 originated from equine influenza.
While no reports have yet been made about CIV being passed onto human hosts, with the Influenza Virus' capability to adapt to different hosts (as seen in the H3N2 and H3N8), the CDC is continuously monitoring the virus both in animal shelters and in homes. Further, CIV outbreaks such as the case in the 2015 where over 1,000 dogs were infected by CIV across the country would likely be prevented should these new vaccines be made available to the public.
