Isolation of varicella-zoster virus from vesicles in children with varicella

Varicella‐zoster virus (VZV) was isolated from 29 samples of the vesicular fluid in 13 otherwise healthy children with varicella who were aged from 7 months to 7 years. Human embryonic lung cells were used for viral isolation, and VZV was identified by a characteristic cytopathic effect and an indirect immunofluorescence assay. VZV was found in 17 samples; in two (12%) of which it was also detected after filtration (0.45 μm). The rate of isolation was 100% in the first two days after the onset of the disease. It declined gradually with time to 1 of 6 in the samples 6 days after the clinical onset. Specific IgG antibody to VZV was investigated in the same materials. The positive rate was 0% (0/13) in the first 3 days and increased to 7 of 16 in the following 3 days after the onset. VZV was not isolated from samples with specific antibody. In conclusion, VZV can be isolated easily from vesicles within the first 3 days of onset, but the filtration of samples affects its isolation. Infective VZV disappears gradually in vesicles after the first 3 days, and this may be related to the establishment of immune reactions including specific antibody. © 1996 Wiley‐Liss, Inc.