Improved identification and differentiation of varicella-zoster virus (VZV) wild-type strains and an attenuated varicella vaccine strain using a VZV open reading frame 62-based PCR.

A new method was developed to identify and differentiate varicella-zoster virus (VZV) wild-type strains from the attenuated varicella Oka vaccine strain. The PCR technique was used to amplify a VZV open reading frame (ORF) 62 region. A single specific amplicon of 268 bp was obtained from 71 VZV clinical isolates and several laboratory strains. Subsequent digestion of the VZV ORF 62 amplicons with SmaI enabled accurate strain differentiation (three SmaI sites were present in amplicons of vaccine strain VZV, compared with two enzyme cleavage sites for all other VZV strains tested). This method accurately differentiated the Oka vaccine strain from wild-type VZV strains circulating in countries representing all six populated continents. Moreover, the assay more reliably distinguished wild-type Japanese strains from the vaccine strain than did previously described methods.

Chickenpox attributable to a vaccine virus contracted from a vaccinee with zoster.

Five months after 2 siblings were immunized with varicella vaccine, 1 developed zoster. Two weeks later the second sibling got a mild case of chicken pox. Virus isolated from the latter was found to be vaccine type. Thus, the vaccine strain was transmitted from the vaccinee with zoster to his sibling. Vaccinees who later develop zoster must be considered contagious. varicella-zoster, zoster, vaccine, transmission, rash, PstI.

Nucleotide sequences that distinguish Oka vaccine from parental Oka and other varicella-zoster virus isolates.

The sequences of approximately 34 kb from the 3' end of the varicella-zoster virus (VZV) Oka vaccine strain and the previously sequenced Dumas strain were compared. Sequence differences were noted in the coding sequences of several VZV open reading frames (ORFs), including ORFs 48, 51, 52, 55, 56, 58, 59, 60, 62, 64, and 68. Tests based on differences in the ORF62 gene and in the ORF64 poly-A region successfully distinguished the Oka vaccine strain from its wild-type parent and from other Japanese and US clinical isolates. These changes remained stable after passage of the virus in humans.

Changes in disposition kinetics of sulphadimidine in response to acute regional liver damage in sheep.

Disposition kinetics of sulphadimidine in sheep, before and after regional liver damage by allyl alcohol, was investigated following a single IV injection (100 mg/kg). Allyl alcohol (12 mg/kg) provoked periportal liver lesion in 60 per cent of the animals. In normal sheep the mean elimination half-life of sulphadimidine was 7.47 +/- 1.09 hours. Liver damage significantly increased this value to 11.68 +/- 1.09 hours. Liver damage by allyl alcohol significantly changed the total body clearance (C1B), the overall elimination rate constant (beta) and the micro-constants k12 and kCl. The apparent volume of distribution (Vd) and the micro-constant k21 were not influenced by liver damage. The mean minimum steady-state concentration (Cp[min]) in normal sheep (38.43 micrograms/ml at 24 hours of interval) was found to be higher than previously reported. Liver intoxication significantly increased this value to 94.38 micrograms/ml. It is suggested that the regional liver damage has affected both the elimination and biotransformation of sulphadimidine.