Information AboutAdenovirus |
| CATEGORIES ABOUT ADENOVIRIDAE | |
| viruses | |
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'' Aviadenovirus '' '' Atadenovirus '' '' Mastadenovirus '' '' Siadenovirus '' Adenoviruses are Virus es of the Family '' Adenoviridae ''. They infect both Human s and Animal s. Adenoviruses were first isolated in human Adenoid s (tonsils), from which the name is derived. Adenoviruses are classifed as group I under the (mainly subgenera B and C), and Conjunctivitis (subgenera B and D), to Gastroenteritis (subgenera F serotypes 40 and 41). Adenoviruses are unusually stable to Chemical or physical agents and adverse PH conditions, allowing for prolonged survival outside of the body and water. Adenoviruses are primarily spread via respiratory droplets, however they can also be spread by Fecal routes as well. GENOME The adenovirus genome is linear, non-segmented double stranded (ds) DNA which is around 30-38 Kbp . This allows the virus to theoretically carry 30 to 40 Genes . Although this is significantly larger than other viruses in its Baltimore group it is still a very simple virus and is heavily reliant on the host cell for survival and replication. An interesting feature of this viral genome is that it has a terminal 55 KDA protein associated with each of the 5' ends of the linear dsDNA, these are used as primers in viral replication and ensure that the ends of the virus' linear genome are adequately replicated. This family contains the following genera:
REPLICATION Adenoviruses possess a linear dsDNA Genome and are able to Replicate in the Nucleus of Mammalian cells using the host’s replication machinery. The adenovirus is generated which is Alternatively Spliced to generate Monocistronic MRNAs compatible with the host’s Ribosome , allowing for the products to be Translated . The early genes are responsible for expressing mainly non-structural, regulatory ; to activate other virus genes (such as the virus-encoded DNA Polymerase ); and to avoid premature death of the infected cell by the host-immune defenses (blockage of Apoptosis , blockage of Interferon activity, and blockage of MHC Class I translocation and expression). Some adenoviruses under specialised conditions can transform cells using their early gene products. E1a (binds Retinoblastoma tumor suppressor protein) has been found to immortalise primary cells in vitro allowing E1b to assist and stably transform the cells. Nevertheless, they are reliant upon each other to successfully transform the host cell and form Tumours . DNA replication separates the early and late phases. Once the early genes have liberated adequate virus genes, replication machinery and replication substrates, replication of the adenovirus genome can occur. A terminal protein that is covalently bound to the 5’ end of the adenovirus genome acts as a Primer for replication. The viral DNA polymerase then uses a strand displacement mechanism, as opposed to the conventional Okazaki Fragments used in mammalian DNA replication, to replicate the genome. The late phase of the adenovirus life cycle is focused on producing sufficient quantities of structural protein to pack all the genetic material produced by DNA replication. Once the viral components have successfully been replicated the virus is assembled into its protein shells and released from the cell as a result of virally induced cell Lysis . ADENOVIRUSES IN HUMANS ADENOVIRUSES IN ANIMALS Two types of Canine adenoviruses are well known, type 1 and 2. Type 1 causes Infectious Canine Hepatitis , a potentially fatal disease involving Vasculitis and Hepatitis . Type 1 infection also can cause respiratory and eye infections. ''Canine adenovirus 2'' (CAV-2) is one of the potential causes of Kennel Cough . Core Vaccine s for Dog s include attenuated live CAV-2, which produces immunity to CAV-1 and CAV-2. CAV-1 was initially used in a vaccine for dogs, but Cornea l Edema was a common complication.1 Adenoviruses are also known to cause respiratory infections in Horse s, Cattle , Pig s, Sheep , and Goat s. ''Equine adenovirus 1'' can also cause fatal disease in Immunocompromised Arabian Foal s, involving Pneumonia and destruction of Pancreatic and Salivary Gland tissue.2 SEE ALSO REFERENCES SOURCES Centers for Disease Control and Prevention--National Center for Infectious Dieseases--Division of Viral and Rickettsial Diseases , Respiratory and Enteric Viruses Branch EXTERNAL LINKS |
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