Isolation of felid herpesvirus I from the trigeminal ganglia of latently infected cats.

Felid herpesvirus I (FHV I) is a respiratory pathogen of cats. Recovered animals remain latently infected but episodes of virus shedding may occur, particularly after stress. Previous attempts to identify the site(s) of latency of FHV I using co-culture, explant or tissue homogenization methods have been unsuccessful. Using a tissue fragment culture technique, however, FHV I was isolated from the trigeminal ganglia of three of 17 cats latently infected with field virus. No virus was found in four cats previously infected with a cold-adapted vaccine strain of FHV I, or in four cats given vaccine strain and field virus. The three trigeminal ganglion isolates had similar plaque size and morphology to the vaccine strain, the plaques being significantly smaller (P less than 0.001) than those of the field viruses.