Although the surveillance system, EIDSS, uses anti-CCHF IgM to confirm acute infection and this investigation found positive anti-CCHF IgG subjects, demonstrating infection sometime within the last five years, comparisons can still be made; EIDSS had been operating for five years prior to this investigation, within the limit of the anti-CCHF IgG seropositivity; thus, the surveillance system had the opportunity to capture these cases. The gene discussed is CD40LG; the disease is infection.