Researchers at The Pirbright Institute will partner with the Belgian biotechnology company ViroVet to develop the first antiviral drugs that act against African swine fever (ASF). In the absence of a vaccine, antiviral drugs could provide an alternative control method which would help limit clinical signs in pigs and lower virus replication. This could reduce the spread of disease and help to contain outbreaks, ultimately reducing the number of pigs lost to this deadly viral infection.
ASF causes an often fatal haemorrhagic disease in pigs that has spread rapidly across Eastern Europe and China, recently appearing in Vietnam and Cambodia. Although the virus is unable to infect humans, it has decimated pig populations which has huge implications for food and economic security. The disease represents an increasing risk to the UK pig industry as well, which is valued at around £1.2 billion per year.
Commercial vaccines have been estimated to be several years away, so the development of alternative control methods is of critical global importance. Antiviral drugs are already used in human medicine to treat diseases such as AIDS and hepatitis C for which no vaccines are available. Pirbright scientists have therefore been funded by the Biotechnology and Biological Sciences Research Council (BBSRC) LINK programme to partner with ViroVet and 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. 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 which the virus usually targets in pigs. This will help to pinpoint how the antivirals work, and allow researchers to optimise the drugs so that they are effective against a wide range of ASF virus strains. The most efficient candidates will then be trialled in pigs to establish safety.
Dr Linda Dixon, Head of the African Swine Fever Group at Pirbright, said: “The unique experience of ViroVet make 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 which 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.”