A virus from horses is bringing us closer to a vaccine against Hepatitis C
A Hepatitis C-like virus in horses could be used for developing a vaccine against the real thing.
A virus that infects horses is so similar to Hepatitis C Virus (HCV) in humans that it might be possible to use horses to develop vaccines against HCV which has infected 200 million people.
That’s the hope of a new study that has demonstrated how horses can be used for vaccine experiments.
"If we’re to be able to develop a vaccine against Hepatitis C we need a good animal model," says Dr. Troels Scheel, a researcher at the Rockefeller University Laboratory of Virology and Infectious Disease. “Our study shows that a similar virus in horses is closely related to HCV and that the symptoms of the disease are alike. This means that we now have a potential animal model on which to develop vaccines.”
Scheel believes the new study can be used to expand our understanding of liver diseases in horses and to understand where HCV in humans actually comes from.
The new discovery has been published in the journal PNAS.
Virus in rodents and bats resemble Hepatitis C
According to Scheel, HCV has probably infected humans for hundreds, perhaps even thousands of years.
Nonetheless, the virus was not discovered until 1989 when it became clear that it spread through blood transfusions and addicts sharing hypodermic needles.
Since then, researchers have been looking for the source of the virus -- that is to say the animal the virus originally came from.
Until now, scientists have only found HCV-like viruses in horses, rodents, and bats, without any of them actually being HCV as it appears in humans.
The closest related virus is one resembling HCV in horses, while the viruses in rodents and bats are more distant relatives.
Because it has not been possible to find a similar virus in animals, the scientists behind the new study elected to focus on the virus which is most similar.
Brings new knowledge of liver diseases in horses
Gaby van Galen teaches at the Department of Large Animal Sciences at the University of Copenhagen and studies equine diseases. She finds the new study fascinating.
"For one thing, the scientists have discovered more about the virus that can give horses hepatitis. It is often extremely difficult to diagnose the cause of liver disease in horses, and the identification of this virus is a breakthrough in equine medicine," says van Galen.
"Second, the study also shows how closely related this hepatitis virus in horses is to Hepatitis C in humans,” she says. “The discovery can help scientists understand -- and potentially help them develop vaccines -- against Hepatitis C in humans.”
Disease symptoms the same in horses as in humans
In the new study, Scheel and colleagues sequencd the genome of the HCV-like virus in horses.
This will enable them to compare the HCV-like virus in horses with HCV in humans and other animals and this will help the scientists discover more about the relationship between the different viruses.
In addition to the sequencing, the scientists have produced a copy of the virus's genome and injected it into the liver of a live horse.
This was to see if the horse reacted in a way that was reminiscent of that of humans -- and thus if horses can be used as animal models for vaccine development.
Turns out they can, says Scheel.
“It means we can study the immune system's response to the virus in horses and study if vaccine candidates have any effect," he says.
The next step towards a new animal model for HCV in humans is to study the HCV-like virus in rodents as these are cheaper to use in vaccine development.
Translated by: Hugh Matthews
- "Characterization of nonprimate hepacivirus and construction of a functional molecular clone", PNAS, DOI: 10.1073/pnas.1500265112