Adenoviruses | |
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Transmission electron micrograph of two adenovirus particles | |
Virus classification | |
Group: | Group I (dsDNA) |
Order: | Unassigned |
Family: | Adenoviridae |
Genera | |
Adenoviruses (members of the family Adenoviridae) are medium-sized (90–100 nm), nonenveloped (without an outer lipid bilayer) viruses with an icosahedral nucleocapsid containing a double stranded DNA genome. Their name derives from their initial isolation from human adenoids in 1953.
They have a broad range of vertebrate hosts; in humans, more than 50 distinct adenoviral serotypes have been found to cause a wide range of illnesses, from mild respiratory infections in young children (known as the common cold) to life-threatening multi-organ disease in people with a weakened immune system.
Group: dsDNA
This family contains the following genera:
Classification of Adenoviridae can be complex.
In humans, there are 57 accepted human adenovirus types (HAdV-1 to 57) in seven species (Human adenovirus A to G):
Different types/serotypes are associated with different conditions:
When not restricting the subject to human viruses, Adenoviridae can be divided into five genera: Mastadenovirus, Aviadenovirus, Atadenovirus, Siadenovirus, and Ichtadenovirus.
Adenoviruses represent the largest nonenveloped viruses. They are able to be transported through the endosome (i.e., envelope fusion is not necessary). The virion also has a unique "spike" or fiber associated with each penton base of the capsid (see picture below) that aids in attachment to the host cell via the receptor on the surface of the host cell. (See Replication Section below for discussion of diverse receptors.)