GENOTYPING OF VARICELLA-ZOSTER VIRUS (VZV) WILD-TYPE STRAINS ISOLATED IN THE CZECH REPUBLIC

Vanda Bostikova,Miroslav Splino,Jan Smetana,Pavel Kosina,Stanislav Plisek,Roman Chlibek,Pavel Bostik,Miloslav Salavec,Petr Prasil

doi:10.5507/bp.2011.056

Abstract

Monitoring of the varicella-zoster virus is becoming an important tool for analysis of the circulation of individual strains of VZV which differ not only at the genomic level, but show a variability in their clinical and epidemiological characteristics. Such data are not available on a large scale from the Czech population and could help understanding the epidemiological and evolutionary characteristics of the virus, as well as its potential for reinfection and increased pathogenesis in the population groups at higher risk for complications. The main aim of this study was detection and monitoring of wild-type or vaccine VZV strain isolates in the region of Eastern Bohemia and genotypic characterization of these isolates. A total of 273 clinical samples were obtained from patients exhibiting symptoms of varicella zoster virus (VZV) infection manifested as chickenpox or herpes zoster (HZ) treated in the Faculty Hospital of Charles University, Medical School in Hradec Kralove, Czech Republic. Characterization of individual short VZV DNA sequences was performed utilizing restriction fragment length polymorphisms (RFLPs), PCR and sequencing. Single nucleotide polymorphisms (SNP) in open reading frames (ORF) 21, 22 and 50 were used to identify individual VZV strains. All clinical isolates (97 from varicella, 176 from herpes zoster) were VZV positive wild-type strains. Sequencing analysis showed that 89 isolates were of the European E1 genotype, 180 were of the European E2 genotype and 2 were identified as the Mosaic M1 strain. In addition, for the first time in this region two unusual genotypes were identified, both representing a combination of E1 and M2 strain specific SNPs. Our prospective VZV genotyping study which is the first to monitor the VZV epidemiological situation in the Czech Republic using such a large set of clinical specimens, has provided valuable epidemiological data and identified two unique VZV recombinants.

Highlights

Varicella zoster virus, a member of Herpesviridae, is a highly contagious and neurotropic virus which infects only humans
In order to investigate the distribution of Varicella-zoster virus (VZV) strains in the Czech Republic on a larger and statistically more significant scale we performed a thorough genomic analy
Genotyping of Varicella-zoster virus (VZV) wild-type strains isolated in the Czech Republic sis of a total of 273 VZV isolates obtained from patients in Kralovehradecky region during the period 2005-2010 (Fig. 1)

Summary

Introduction

A member of Herpesviridae, is a highly contagious and neurotropic virus which infects only humans. All herpes viruses have the capacity to induce life-long latency in the infected organisms from which viruses can be reactivated at any time. VZV is the only human herpetic virus exhibiting an entirely different clinical picture during the primoinfection vs reactivation. The primoinfection – chickenpox – is typically a seasonal, predominantly childhood disease with peaks during late winter and early spring. In tropical and subtropical regions the peak incidence of chickenpox is during adolescence[1]. There is no seasonality of the disease in tropical countries. The genome of VZV consists of 125-kp of double – stranded DNA and is extremely stable[2]. The variability between individual strains is only ∼ 0.1% and is manifested as single nucleotide polymorphisms (SNP) (ref.[3])

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Conclusion