favipiravir and West-Nile-Fever

We report a case of tick-borne encephalitis (TBE) in a 22-year-old man, who was admitted to the Medical University of Vienna hospital with severe meningoencephalitis, unresponsive and dependent on a respirator. He had given a history of a recent tick bite, but because he had previously received a full course of vaccination against TBE, West Nile virus infection was suspected. Because the antiviral drug favipiravir has been reported to be active against WNV, therapy was initiated, and continued even after a diagnosis of TBE was confirmed, due to significant improvement of symptoms. Within days, the patient's symptoms resolved, and he was discharged after complete recovery at 15 days after onset. Although this single case does not permit any conclusion as to the role of favipiravir in the favorable outcome, it suggests that the drug should be further evaluated in laboratory animal models and in appropriate clinical settings.

Topics: Adult; Amides; Diagnosis, Differential; Encephalitis Viruses, Tick-Borne; Encephalitis, Tick-Borne; Humans; Male; Pyrazines; Vaccination; West Nile Fever; Young Adult

We describe herein that a pyrazine derivative, T-705 (6-fluoro-3-hydroxy-2-pyrazinecarboxamide), is protective for a lethal West Nile virus infection in rodents. Oral T-705 at 200 mg/kg administered twice daily beginning 4h after subcutaneous (s.c.) viral challenge protected mice and hamsters against WNV-induced mortality, and reduced viral protein expression and viral RNA in brains. The minimal effective oral dose was between 20 and 65 mg/kg when administered twice a day beginning 1 day after viral s.c. challenge of mice. Treatment could be delayed out to 2 days after viral challenge to still achieve efficacy in mice. Further development of this compound should be considered for treatment of WNV.

Topics: Administration, Oral; Amides; Animals; Brain; Cricetinae; Disease Models, Animal; Drug Administration Schedule; Female; Humans; Mesocricetus; Mice; Mice, Inbred C57BL; Pyrazines; West Nile Fever; West Nile virus