In contrast, IDO induction acts in vitro and/or in vivo against bacteria, such as Chlamydiae, Streptococci and Staphylococci species [19-21]; parasites, for example Toxoplasma gondii[21]; and viruses, including herpes simplex-2 virus (HSV-2), cytomegalovirus (CMV), hepatitis B virus (HBV), and vaccinia virus infections [22-25]. The gene discussed is IDO1; the disease is viral infectious disease.