Varicella-Zoster virus gene expression at variable periods following death in a rat model of ganglionic infection

We used a rat model of Varicella-Zoster virus (VZV) ganglionic infection, which mirrors some of the features of VZV latency in humans, to determine the temporal pattern of expression of a VZV immediate-early gene (63) and a VZV late gene (40) at 0, 24 and 48 h after death of the animal. The immediate-early VZV gene 63 is known to be abundantly expressed during human ganglionic latency, while the late VZV gene 40 is not expressed during human latency. Using both RNA in situ hybridisation (ISH) and nested RT-PCR, it was found that at all time points in both thoracic and lumbar ganglia, the number of ganglia positive for VZV gene 63 was higher than for gene 40. The expression of gene 40 did not increase with time postmortem (pm) These results provide indirect support for the hypothesis that patterns of expression of VZV genes detected in human tissue at even 48 h pm reflect the pattern of expression during human ganglionic latency.