Potential of antiviral therapy and prophylaxis for controlling RNA viral infections of livestock

Abstract

With intensification of trade, livestock are increasingly exposed to severe animal diseases caused by a range of RNA viruses. Recent prime examples include outbreaks of foot-and-mouth disease (FMD), peste des petits ruminants, Rift Valley fever and bluetongue. To minimise their impact, controlling the spread of virus is of utmost importance. Good quality, reliable vaccines exist for some, although not all, of these diseases, but suffer from a set of drawbacks, not the least of which being the time needed to trigger the immune response (i.e. "immunity-gap"). Effective, rapid control tools are, therefore, urgently needed and antiviral compounds could serve this purpose. Although limited in vitro and in vivo research has been performed, encouraging results for FMD suggest that livestock could be protected against infection within 24h following antiviral treatment and up to 12h post-infection. Such prophylactic/therapeutic antiviral drugs could complement emergency vaccination in a previously disease-free setting or be applied to treat valuable zoological collections and breeding stocks in endemic and previously disease-free regions alike. This paper will primarily focus on the effects of FMD on livestock and other sectors, and on appropriate control tools. The outlined principles can be extrapolated to other RNA viral diseases.