The infection of these mice with CCHFV produced neurological disease, prolonged infection time, and led to death at 13–23 dpi.572 A mouse-adapted CCHFV strain (MA-CCHFV) was generated via serial passages of CCHFV-Hoti in Rag2−/− mice (deficient in adaptive immunity, recombination-activating-gene) and C57BL/6J mice. The gene discussed is RAG2; the disease is infection.