Determining the prevalence of herpes simplex virus type 1 (HSV‐1) in ganglia of the human head and neck

The purpose of this study was to investigate the prevalence and correlation of HSV‐1 positive ganglia in multiple locations within the head and neck of human cadavers. Ganglia were carefully dissected from formalin‐fixed cadavers avoiding cross‐contamination between samples. After tris/glycine/EDTA overnight washings (pH 8.0) to reverse formalin cross‐linking, DNA was extracted from the trigeminal, ciliary, pterygopalatine, geniculate, otic, submandibular, superior cervical, and nodose ganglia. Using nested PCR, the presence of HSV‐1 was determined (RL2 gene). McNemar's comparison of the sixteen ganglia in each cadaver (8/side) revealed no statistically significant correlation between detection of HSV‐1 sequences in one ganglion and the presence of HSV‐1 in other ganglia (ipsi‐ and contralateral). Since there was no predictability between HSV‐1 positive ganglia, evaluation of latency in the human head must be done separately for each ganglion. These results suggest that reactivation of virus from any of these ganglia could result in reactivation disorders (e.g. Bell's palsy or acute retinal necrosis). Thus, more than the trigeminal ganglion needs to be considered when studying HSV‐1 latency.