Researchers at The Pirbright Institute in the U.K. will partner with the ViroVet biotechnology company in Belgium to develop the first antiviral drugs that act against African swine fever (ASF), the institute said May 29.
In the absence of a vaccine, antiviral drugs could provide an alternative control method that would help limit clinical signs in pigs and lower virus replication, the institute said. This could reduce the spread of disease and help contain outbreaks, ultimately reducing the number of pigs lost to this deadly viral infection.
ASF causes an often fatal hemorrhagic disease in pigs that has spread rapidly across Eastern Europe and China, recently appearing in Vietnam and Cambodia.
Commercial vaccines are estimated to be several years away, so the development of alternative control methods is of critical global importance, Pirbright explained. Antiviral drugs are already used in human medicine to treat diseases for which no vaccines are available, such as AIDS and hepatitis C.
With funding from the LINK program of the U.K.'s Biotechnology & Biological Sciences Research Council, Pirbright scientists partnered with ViroVet to develop antiviral drugs that are effective against ASF.
The drugs have already been screened in the laboratory for their ability to prevent viral replication and reducing toxicity to pig cells, Pirbright said. So far, these antivirals have demonstrated a 90% reduction rate in viral replication. The most successful candidates will be further tested at Pirbright’s unique high containment facilities.
Scientists will assess whether the antiviral drugs are effective at preventing 14 different types of ASF virus from replicating in macrophages — immune cells that the virus usually targets in pigs. This will help pinpoint how the antivirals work and allow researchers to optimize the drugs so they are effective against a wide range of ASF virus strains, the announcement said. The most efficient candidates will then be tested in pigs to establish safety.
Dr. Linda Dixon, head of the ASF group at Pirbright, said, “The unique experience of ViroVet makes them the ideal company to partner with on this project. The results from this study will help us understand more about how the virus infects pigs and will help to inform our vaccine development research. Without a viable vaccine, ASF is incredibly difficult to control, owing to its ability to be spread by wild boar and through the consumption of contaminated pork and other products by pigs.
"Having a tool that could lower the risk of further transmission once pigs have been infected would go a long way in preventing the rapid spread of this disease,” Dixon added.