Adenoviridae

A family of viruses that infect a variety of hosts

Adenoviridae is a family of viruses that infect a wide range of hosts, including humans, other mammals, birds, reptiles, and fish. These viruses are known for their ability to cause a variety of diseases, ranging from mild respiratory infections to more severe illnesses.

Structure

Adenoviruses are non-enveloped viruses with an icosahedral capsid structure. The capsid is composed of 240 hexon proteins and 12 penton bases, which are located at the vertices of the icosahedron. Each penton base is associated with a fiber protein that protrudes from the capsid and is responsible for attachment to host cells.

Diagram of adenovirus structure

Genome

The genome of adenoviruses is composed of linear, double-stranded DNA. The genome size ranges from 26 to 45 kilobase pairs, depending on the species. The genome encodes for approximately 30 to 40 proteins, which are involved in various stages of the viral life cycle, including replication, assembly, and host immune evasion.

Diagram of adenovirus genome

Replication

Adenoviruses replicate in the nucleus of the host cell. The replication cycle begins with the attachment of the virus to the host cell surface via the fiber protein. Following attachment, the virus is internalized and transported to the nucleus, where the viral DNA is released. The host cell's machinery is then hijacked to transcribe and replicate the viral genome. New virions are assembled in the nucleus and released upon cell lysis.

Pathogenesis

Adenoviruses are capable of causing a wide range of diseases. In humans, they are commonly associated with respiratory illnesses, such as the common cold, pneumonia, and bronchitis. They can also cause gastroenteritis, conjunctivitis, and cystitis. In immunocompromised individuals, adenovirus infections can be severe and potentially life-threatening.

Epidemiology

Adenoviruses are ubiquitous and can be transmitted via respiratory droplets, fecal-oral route, and direct contact with contaminated surfaces. They are responsible for outbreaks in crowded settings, such as military barracks and daycare centers. Vaccines are available for certain serotypes, particularly those that cause respiratory illness in military recruits.

Related pages

• Virus
• Respiratory infection
• Viral replication
• Immune system

Gallery

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  Adenovirus type 4
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  Electron micrograph of adenovirus