This study investigated for the presence of EBV in MS brain tissue detecting EBV by PCR and EBER ISH. 47/101 cases were positive for EBV in meninges.EBER ISH showed EBV positive cells in 83/101 MS cases–80/101 EBV+ cells detected in brain parenchyma and 60/101 EBV+ cells detected in meninges. 5/21 non-MS neurological controls had evidence of EBV+ cells. Double staining IHC performed on 18 EBV heavily infected cases identified 11/18 and 7/18 cases were found to be double positive for EBV/GFAP and EBV/Iba-1 respectively. The gene discussed is AIF1; the disease is myeloid sarcoma.