MONDAY, SEPTEMBER 26, 2016

Georgia researchers unveil PIV5 vaccine to combat rabies

A study at the University of Georgia has discovered a new treatment on mice that can potentially cure rabies, even after the virus has spread to the brain, where it would then be fatal.

"Basically, the best way to deal with rabies right now is simple: Don't get rabies," Biao He, study co-author and  College of Veterinary Medicine professor at the university, said. "We have vaccines that can prevent the disease, and we use the same vaccine as a kind of treatment after a bite, but it only works if the virus hasn't progressed too far. Our team has developed a new vaccine that rescues mice much longer after infection than what was traditionally thought possible."

In He’s experiments, the mice were exposed to a strain of the rabies virus that generally reaches the brain of infected mice within three days. By the sixth day, the mice typically begin to exhibit the fatal symptoms; however, 50 percent of mice treated with the new vaccine were saved, even after the signs of the fatal symptoms appeared on day six.

"This is the most effective treatment we have seen reported in the scientific literature," He said. "If we can improve these results and translate them to humans, we may have found one of the first useful treatments for advanced rabies infection."

The vaccine was created by inserting a protein from the rabies virus into another virus, parainfluenza virus 5, (PIV5), which many scientists believe contributes to upper respiratory infections in dogs, but is harmless to humans. PIV5 then acts as a vehicle that carries the rabies protein to the immune system where it can create the antibodies necessary to ward off the virus.

"This is only the beginning of our work," He said. "While these preliminary results are very exciting, we are confident that we can combine this new vaccine with other therapies to boost survival rates even higher and rescue animals even when symptoms are severe."

Study co-author Zhen Fu, a pathology professor at the University of Georgia, said PIV5 works wonders.

"It doesn't matter how we weaken the current vaccine, the virus inside it is still rabies," Fu said. "That is not a concern with our PIV5 vaccine."

The researchers will continue to work on the vaccine's design with an eye on using it in more advanced animal trials in the future.

"There is an urgent need in many parts of the world for a better rabies treatment, and we think this technology may serve as an excellent platform," He said. "Ultimately, we just want to try to save more lives."

The findings of the study were published recently in the Journal of Virology.