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Varicella structure, genome and pathogenesis

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Varicella zoster virus causes chickenpox and shingles. It has a double-stranded DNA genome that is linear and 125 kbp in length. The genome contains over 70 genes including genes that regulate virus transcription. VZV is transmitted through direct contact with skin lesions or respiratory secretions. Primary infection causes chickenpox while reactivation from latent infection causes shingles, presenting as a painful rash in a dermatomal distribution. The virus establishes latency in dorsal root ganglia after primary infection and can reactivate decades later to cause shingles.

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INDIAN INSTITUTE OF TECHNOLOGY ROORKEE Structure, Genomic Information and Pathogenesis of Herpes Zoster Virus Submitted by:- Sourik Dey 18610023 Vaccine Development and Production M.Sc. Biotechnology (IInd Year) Submitted to : Prof. R.P. Singh
2 Varicella Zoster Virus (VZV) • Varicella-zoster virus (VZV) causes chickenpox and herpes zoster (shingles). • Chickenpox follows initial exposure to the virus and is typically a relatively mild, self- limited childhood illness with a characteristic exanthem, but can become disseminated in immunocompromised children. • Reactivation of the dormant virus results in the characteristic painful dermatomal rash of herpes zoster, which is often followed by pain in the distribution of the rash (postherpetic neuralgia). Electron micrograph of a Human alphaherpesvirus 3 virus
3 Structure of Varicella Zoster Virus
4 Genome of Varicella Zoster Virus Image Source: DOI: 10.1128/CMR.00031-09
5 Genome Distribution • The virus contains a double-stranded DNA genome and is linear measuring 125 kbp in length. • The genome consists of a unique long region (UL) bounded by terminal long (TRL) and internal long (IRL) repeats, and a unique short region (US) bounded by internal short (IRS), and terminal short (TRS) repeats. • The varicella-zoster virus (VZV) genome contains at least 70 genes. • VZV encodes at least 3 immediate-early (IE) proteins that are located in the tegument of virions and regulate virus transcription. • The VZV genome contains about 41 “core genes” that are conserved with each of the three subfamilies of herpesviruses, alphaherpesvirus, betaherpesvirus, and gammaherpesvirus. • Core genes include IE4, the VZV DNA polymerase, helicase-primase components, single-stranded DNA-binding protein, ribonucleotide reductase, uracil-DNA glycosylase, dUTPase, DNase, ORF47 protein kinase, major capsid protein, protease, assembly protein, several tegument proteins, gB, gH, gL, gM, and gN.
6 Pathogenesis of Virus VZV is transmitted in the following ways:- • by spread - oropharyngeal secretion. • through direct contact - fluid of skin lesions.
7 Primary Infection Secondary Infection
8 Mechanism of Viral Infection Image Source: DOI: 10.1128/CMR.00031-08
9 Shingles Development
10 Course of Pathogenesis
11 Thank You

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Varicella structure, genome and pathogenesis

  • 1. INDIAN INSTITUTE OF TECHNOLOGY ROORKEE Structure, Genomic Information and Pathogenesis of Herpes Zoster Virus Submitted by:- Sourik Dey 18610023 Vaccine Development and Production M.Sc. Biotechnology (IInd Year) Submitted to : Prof. R.P. Singh
  • 2. 2 Varicella Zoster Virus (VZV) • Varicella-zoster virus (VZV) causes chickenpox and herpes zoster (shingles). • Chickenpox follows initial exposure to the virus and is typically a relatively mild, self- limited childhood illness with a characteristic exanthem, but can become disseminated in immunocompromised children. • Reactivation of the dormant virus results in the characteristic painful dermatomal rash of herpes zoster, which is often followed by pain in the distribution of the rash (postherpetic neuralgia). Electron micrograph of a Human alphaherpesvirus 3 virus
  • 4. 4 Genome of Varicella Zoster Virus Image Source: DOI: 10.1128/CMR.00031-09
  • 5. 5 Genome Distribution • The virus contains a double-stranded DNA genome and is linear measuring 125 kbp in length. • The genome consists of a unique long region (UL) bounded by terminal long (TRL) and internal long (IRL) repeats, and a unique short region (US) bounded by internal short (IRS), and terminal short (TRS) repeats. • The varicella-zoster virus (VZV) genome contains at least 70 genes. • VZV encodes at least 3 immediate-early (IE) proteins that are located in the tegument of virions and regulate virus transcription. • The VZV genome contains about 41 “core genes” that are conserved with each of the three subfamilies of herpesviruses, alphaherpesvirus, betaherpesvirus, and gammaherpesvirus. • Core genes include IE4, the VZV DNA polymerase, helicase-primase components, single-stranded DNA-binding protein, ribonucleotide reductase, uracil-DNA glycosylase, dUTPase, DNase, ORF47 protein kinase, major capsid protein, protease, assembly protein, several tegument proteins, gB, gH, gL, gM, and gN.
  • 6. 6 Pathogenesis of Virus VZV is transmitted in the following ways:- • by spread - oropharyngeal secretion. • through direct contact - fluid of skin lesions.
  • 8. 8 Mechanism of Viral Infection Image Source: DOI: 10.1128/CMR.00031-08