Neuron to neuron transmission of herpes simplex virus. Transport of virus from skin to brainstem nuclei.

Herpes simplex virus (HSV) injection into the snout of mice was followed by the appearance of HSV antigen in neurons in trigeminal ganglia, main sensory and spinal tract trigeminal nuclei, reticular formation including raphe nuclei and locus ceruleus on both sides. The findings indicate that HSV spreads via axons, passes through a series of neurons and in this way can reach vital nuclei in the brainstem including monoaminergic neurons from the primary replication area in the lip.