The number of herpes simplex virus-infected neurons and the number of viral genome copies per neuron correlate with the latent viral load in ganglia.

The latent viral load is the most important factor that predicts reactivation rates of animals latently infected with herpes simplex virus (HSV). To estimate the latent viral load, individual latently infected mouse trigeminal ganglia were dispersed into single cell suspensions and plated into 96-well real-time PCR plates, and HSV-2 genome copies were measured. By assuming a Poisson distribution for both the number of HSV-2 infected cells per well and the number of HSV-2 genome copies per infected cell, the numbers of infected cells and mean genome copies per infected cell were determined. Both the number of HSV-2 infected cells and the mean HSV-2 genome copy per infected cell significantly correlated with the latent viral load (p<10(-4)), indicating that both factors are responsible for the increase in the latent viral load.