Immunocompetent mice don’t display clinical signs or viremia when challenged with CCHFV, therefore, STAT1 KO mice were infected with 100 PFU of CCHFV strain IbAr 10200, a model we previously described20, and showed clinical signs of infection beginning on day 3 and reached the predefined humane endpoint on day 4 post inoculation. The gene discussed is STAT1; the disease is infection.