Localization of herpes simplex virus and varicella zoster virus DNA in human ganglia

Human dorsal root ganglia from 14 randomly autopsied adults and 1 infant (all seropositive for both herpes simplex virus [HSV] and varicella zoster virus [VZV]) were examined for latent HSV‐1 and VZV DNA by polymerase chain reaction. Thoracic ganglionic DNA from all subjects and trigeminal ganglionic DNA from 11 adults were analyzed. HSV‐1 DNA was detected in trigeminal ganglia from 8 of 11 (73%) adults and in thoracic ganglia from 2 of 14 (14%) adults. VZV DNA was detected in trigeminal ganglia from 10 of 11 (91%) adults and in thoracic ganglia from 12 of 14 (86%) adults. None of the DNA samples were positive with primers specific for HSV‐2. These findings indicate the presence of latent HSV‐1 and VZV DNA in trigeminal ganglia and latent VZV DNA in thoracic ganglia of most seropositive adults. Furthermore, although HSV‐1 latency most commonly develops in trigeminal ganglia, we also show for the first time the presence of HSV‐1 latency in thoracic ganglia. Finally, both viruses can become latent in the same trigeminal ganglion.