Interferons, interferon inducers, and interferon-ribavirin in treatment of flavivirus-induced encephalitis in mice.

We evaluated the prophylactic and therapeutic efficacy of interferon alpha-2b, pegylated interferon alpha-2b, poly(I. C), and Ampligen against Modoc virus encephalitis in an animal model for flavivirus infections. All compounds significantly delayed virus-induced morbidity (paralysis) and mortality (due to progressive encephalitis). Viral load (as measured on day 7 postinfection) was significantly reduced by 80 to 100% in the serum, brain, and spleen in mice that had been treated with either interferon alpha-2b, pegylated interferon alpha-2b, poly(I. C), or Ampligen. We also studied whether a combination of interferon alpha-2b and ribavirin (presently the standard therapy for the treatment of infections with hepatitis C virus) would be more effective than treatment with interferon alone. However, ribavirin did not enhance the inhibitory effect of interferon therapy in this animal model for flavivirus infections.