PTGS2 and disease arising from reactivation of latent virus: Normal to Latent infections: In the early infection (latent infection), we have identified 28 genes which are differentially expressed in the host system, of which 12 genes (IER5L, MS4A6A, DOK2, FZD2, NCKI-ASI, SNHG12, NLRC4, XPO7, SMA4, CD36, AFFI, and NDUFS8) were up-regulated, and 16 genes (IL1A, IL6, ACOD1, IL1B, ELOVL7, PTGS2, EREG, F3, IFIT1, TNF, KANK1, CCL4, CXCL11, PTX3, IRAK2, and AREG) were down-regulated.