Adenoviridae are a group of double-stranded DNA viruses with an icosahedral nucleocapsid. Many Adenoviridae have been isolated from mammals and birds, but only a small number of these cause significant veterinary disease. The family consists of four genera: Mastadenovirus, Aviadenovirus, Atadenovirus and Siadenovirus. Canine adenovirus 1 is a Mastadenovirus.
Viral Characteristics
The genetic information of Adenoviridae is conveyed by a single, linear molecule of double-stranded DNA which encodes around 30 proteins. Under the influence of both host and virus-encoded factors, the DNA replicates and is transcribed within the host nucleus, where virion assembly also occurs. Basophilic and/or acidophilic inclusions may therefore be seen in the nucleus of an adenovirus-infected cell.
The virus genome is contained within a non-enveloped icosohedral nucleocapsid, which comprises capsomeres (called hexons) and twelve vertex capsomeres (called pentons). A fibre antigen protrudes from each of the twelve pentons, and this attaches to host cell receptors as well as being a type-specific haemagglutinin. This fibre antigen is a feature specific to the Adenoviridae. The hexon of mammalian adenoviruses contains a cross-reacting group antigen.
Introduction
Morphology
- Stable, non-enveloped, resistant
- Icosahedral virus:
- Capsomeres at apices (12) carry a peripheral fiber with a terminal knob
- Capsomeres on facets (240) do not