Adenovirus

The virus

  • Non-enveloped linear ds-DNA virus. Icosahedral symmetry (70-90 nm diameter).

  • The capsid has three major proteins – hexon, penton, and fibre.

  • Ubiquitous in nature. Most people are seropositive by the age of 10 years.

  • Adenovirus can be divided into 4 genera.

  • Mammalian adenovirus belongs to the genus Mastadenovirus.

  • Human adenovirus is a part of this genus.

Adenovirus electron microscope picture

Adenovirus Electron Micrograph (GrahamColm, Wikipedia)

Adenovirus diagram (free)

Adenovirus classification

Human adenovirus has 7 species based on their haemagglutination character.

Each species was further divided into serotypes based on neutralisation (e.g. A- 12,18, 31). At present, genotyping is being used to classify Adenovirus.

Different species of human adenovirus has different tissue tropism.

Classification of adenovirus

Tissue tropism

Adenovirus receptors

  • Coxsackie B virus–adenovirus receptor (CAR),

  • CD46, CD80, CD86

  • Sialic acid, heparan sulfate proteoglycans.

Viral replication

Virus replication site - Nucleus

Stages of adenovirus replication

Stages of adenovirus replication

Immune modulation by adenovirus

DURING THE REPLICATION PROCESS VIRUS RELEASES PROTEIN TO MODULATE THE IMMUNE SYSTEM

  • Inhibit MHC-1 expression

  • Downregulation of fas, TNF

  • Inhibition of apoptosis (TRAIL receptor)

Latent infection

Adenovirus can remain latent in the T-lymphocytes of tonsils and adenoid.

Route on transmission of adenovirus

Droplet, faeco-oral.

Adenovirus infection

Adenovirus is commonly seen in 3 groups of people – children, immunocompromised and military recruits.

50% of adenovirus infection is asymptomatic.

Up to 10% of febrile illnesses in children are due to adenovirus.

Laboratory diagnosis

Adenovirus - Smudge Cells

Adenovirus - Smudge Cells ( Adenoviruses Copyright © 2022, StatPearls Publishing LLC.) Creative Commons Attribution 4.0

Treatment

Vaccine

A vaccine has been developed for military recruits.