In a significant breakthrough in infectious disease research, Dr. Ariel Isaacs, an infectious diseases virologist at the University of Queensland, has turned to an unlikely hero: an eight-year-old Chilean alpaca named Pedro. With this novel approach, they are plugging away at the world’s first human vaccine against the catastrophic Hendra virus. It is a very dangerous virus for horses and humans alike.
The Hendra virus that causes it first appeared in 1994 in a Brisbane suburb with the same name. Since then, it has resulted in 68 outbreaks and the death of 110 infected horses. The mortality rate for humans infected with the virus is significantly high at almost 60 percent. Since its initial detection, there have been four confirmed deaths. The virus continues to spread rapidly through bat populations. This continued circulation presents a danger to people, since infected horses can spread the virus even before they start showing signs of illness.
Understanding Hendra Virus and Its Risks
Fruit bats are the main reservoir for the Hendra virus, which is transmitted to horses, and to humans from there. Humans are at risk if they’re in contact with these infected animals. This creates significant burdens for both veterinarians and equine practitioners. Dr. Reid, a veterinarian, powerfully describes the trauma of having witnessed the first outbreak. She witnessed thousands of horses in distress, literally bleeding out and perishing, a visceral scene that has haunted her ever since.
“In the space of 36 hours, I think there were nine horses that died or I had to put down … it was just catastrophic because I didn’t know what was killing them,” – Dr. Reid.
Add to that the unique and insidious nature of this virus, and you have a particularly dangerous situation. Horses may begin to shed the virus 24-48 hours before they exhibit any symptoms. This significantly raises the chance of inadvertently exposing people to the virus. As Dr. Reid pointed out, if we don’t have the right infrastructure in place, the risk for outbreaks is very real.
“Horses can be shedding virus before they become sick, so you can be at risk and not realize,” – Dr. Reid.
With the landscape of Hendra virus outbreaks still burgeoning, the need for successful preventative measures is critical. Dr. Reid is passionate about vaccinating horses and is an outspoken proponent for horse vaccinations. This strategy is key to interrupting the transmission cycle among bats, horses, and humans.
“We know the best way to prevent people being infected is to stop the transmission from fruit bats and horses to people, and that is by vaccinating the horses,” – Dr. Reid.
Pedro’s Role in Vaccine Development
Dr. Isaacs has been working with Pedro-produced nanobodies. These nanobodies have proven to be extremely powerful as virus neutralizers against a variety of viruses. These nanobodies provide a powerful advantage from the start with their amenability to engineering for next-generation, personalized, targeted therapies. Dr. Isaacs and Professor Daniel Watterson continued to work closely to create a human vaccine against the Hendra virus. They are fueling the potential of these nanobodies in their pioneering research.
Under the direction of Professor Watterson, a team of vaccine specialists has been working to create vaccines and therapies for emerging viruses. He warned that we must be on guard against similar viruses that could appear elsewhere in the world.
“Nipah virus, for example, is something that is now emerging across Asia, India, and Bangladesh in particular,” – Professor Daniel Watterson.
This pioneering research by Dr. Isaacs and Professor Watterson. Their efforts do provide hope for creating a vaccine that is both safe and effective — capable of protecting human populations and equine populations alike from the deadly Hendra virus.
The Road Ahead
Developing a human vaccine goes far beyond scientific interest. Its ability to protect lives is profound not only for veterinarians, but for anyone who comes in contact with horses. The history surrounding Hendra underscores the disastrous effects of outbreaks and the necessity for a preparedness plan.
Dr. Isaacs noted the rapid progression of symptoms once infected with Hendra virus, stressing the critical need for vaccine development.
“Usually within a few days you get severely sick and then within a week you can be in a coma and then after that, if there’s no treatment, you can easily die from infection,” – Dr. Ariel Isaacs.
As researchers move forward in their work with Pedro’s nanobodies, they are hopeful for the positive impact they could have on public health. As Dr. Reid warned, complacency can’t be an option either.
“Don’t think that it can’t happen to you, because it can,” – Dr. Reid.
