CLASSIFICATION, DIVERSITY AND STRUCTURE OF ADENOVIRUS

CLASSIFICATION

Adenovirus can be classified into fives genera that are Genus Atadenovirus, Genus Aviadenovirus, Genus Ichtadenovirus, Genus Mastadenovirus and Genus Siadenovirus.

Genus Atadenovirus

Atadenoviruses infect animal with a broad host range from several vertebrate classes. It has capsid fibers, a core, and associated protein. Their capsids are not enveloped but have icosahedral symmetry. The isometric capsid has a diameter of 80-100 nm. The capsid shells of virions are composed of a single layer. Capsids appear hexagonal in outline.

Genus Aviadenovirus

These types of virus are mainly infected bird species.

Genus Ichtadenovirus

This family of adenovirus share very similar characteristic with other genus such as the genome has terminally redundant sequences which have inverted terminal repetitions (ITR).its structure also very similar to Aviandenovirus. The terminal protein (TP) is covalently attached to each end of the genome. But, their hosts are not very known for now.

Genus Mastadenovirus

This virus can cause respiratory infections and acute follicular conjunctivitis to many species including human.

Genus Siadenovirus

This virus comprising species such as frog and turkey.

The genome of all this genus share same similar characteristic that are their genomes are non segmented, linear double-stranded DNA of 35-36kb encoding about 40 proteins. The genome has terminally redundant sequences which have inverted terminal repetitions (ITR). The terminal protein (TP) is covalently attached to each end of the genome.

DIVERSITY

Diversity of adenovirus is very complex. There are 54 types of human adenovirus comprising of seven species (A to G).
• A: 12, 18, 31
• B: 3, 7, 11, 14, 16, 34, 35, 50
• C: 1, 2, 5, 6
• D: 8, 9, 10, 13, 15, 17, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 33, 36, 37, 38, 39, 42, 43, 44, 45, 46, 47, 48, 49, 51, 53, 54
• E: 4
• F: 40, 41
• G: 52

Adenovirus serotype 14 in types B is known to cause potentially fatal adenovirus infections. This type of virus can cause severe respiratory infection.
For adenovirus serotype 36, it is also known to infect human being. It was first isolates from the girl that have diabetes and enteritis. It is also cause respiratory and eye infection to human. The relationship between body fat and this type of virus have a positive correlation.
Other types of adenovirus can cause several diseases such as species B and C can cause respiratory disease to human. Species B and D also can cause conjunctivitis to human and serotype 4o and 41 in species F can cause gastroenteritis.



STRUCTURE

The structure of adenovirus genome are Non segmented, linear double-stranded DNA of 35-36kb. The genome has terminally redundant sequences which have inverted terminal repetitions (ITR). The terminal protein (TP) is covalently attached to each end of the genome.






This virus also contained capsid as their genome protection. Adenoviruses are double-stranded DNA viruses. They have icosahedral capsids with twelve vertices and seven surface proteins. The virion is non-enveloped, spherical and about seventy to ninety nm in size. The genome encodes about thirty proteins. This virus also consisted of spike for infection.