Antiviral effect of ribavirin on Junin virus replication in vitro

The effect of Ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) on the replication in vitro of Junin virus, the causative agent of Argentine Hemorrhagic Fever (AHF), was examined. A concentration as low as 3.12 micrograms/ml of the drug inhibited the cytopathic effect observed five days post-infection (pi) on Vero cells. On the other hand, a concentration of 25 micrograms/ml reduced the virus yield and specific antigen formation to undetectable levels. This same concentration of Ribavirin prevented plaque formation under methylcellulose. The high sensitivity of Junin virus to Ribavirin in vitro, the low toxicity of the drug for mammals and the therapeutic effect observed on in vivo infections with other arenaviruses, makes Ribavirin a promising antiviral agent that deserves testing on AHF primate models before clinical trials are undertaken.