- Echovirus
Taxobox
name = "Echovirus"
virus_group = iv
familia = "Picornaviridae "
genus = "Enterovirus "
species = "Human enterovirus B "
subdivision_ranks = Subtype
subdivision = "Echovirus"An echovirus is a type of
RNA virus that belongs to thegenus "Enterovirus " of the "Picornaviridae " family.cite book | author = Ryan KJ; Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | pages = 537–9 |publisher = McGraw Hill | year = 2004 | id = ISBN 0838585299 ] Echoviruses are found in the gastrointestinal tract (hence it being part of the enterovirus genus) and exposure to the virus causes other opportunistic infections and diseases.History
The first isolation of echoviruses occurred from the
feces ofasymptomatic children early in the 1950s, just after cell culturing had been developed. The "echo–" part of the name was originally anacronym for "enteric cytopathic human orphan" virus: "Orphan virus" means a virus that is not associated with any known disease. Even though Echoviruses have since been identified with various diseases, the original name is still used.cite book | author = subst:CURRENTMONTHNAME subst:CURRENTYEARin-Murphy M, Almond JW | title = Picornavirues. "in:" Baron's Medical Microbiology "(Baron S "et al", eds.)| edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | url = http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.2862 | id = ISBN 0-9631172-1-1 ]Description
Echovirus is highly infectious, and its primary target is children. The echovirus is among the leading causes of acute febrile illness in infants and young children, and is the most common cause of
aseptic meningitis .eMedicine|ped|629] Infection of an infant with this virus following birth may cause severesystemic disease s, and is associated with highinfant mortality rates. The echovirus can mimicsymptom s caused by other commonbacteria l and viralinfection s, so echovirus infections are often treated with therapies aimed for other infections. This can lead to the evolution ofantibiotic-resistant bacteria.Viral structure and infection
An echovirus measures 24-30 nanometres (nm), and is similar to other viruses, since it has a naked
protein capsid , which makes up 75% of the virus particle that encloses a dense central core of single-strandedRNA . This RNA has a length of approximately 7.5kilobase (kb), contains anRNA replicase ,viral-coded protein s, and a singlepolyprotein that is responsible for the formation ofstructural protein s and other proteins necessary forcellular replication . The structural proteins determinehost range and play a very important role in delivering the RNAgenome into thecytoplasm of new host cells.Some viral replication of an echovirus occurs in the
nasopharynx after infection and then spreads to regionallymph node s. However, most viral particles are swallowed and they reach the lowergut tract , where the virus is presumed to bind to specific receptors. The virus then spreads to the lowerintestinal tract , replicating but not causing any major cellular effects along the way. Next, the virus spreads to many secondary sites in the body such as thecentral nervous system ,liver ,spleen ,bone marrow ,heart and finally thelung s. Additional replication of the virus will occur, causing symptoms 4 to 6 days after infection. The most deadly part however is delayed when symptoms of a central nervous system disease start to appear. Enteroviruses are capable of infecting any cell in the body. These viruses are highly infectious. They can spread through the air to other hosts 1-3 weeks after infection and can spread through feces to other hosts eight weeks after infection.ymptoms and diagnosis
Echovirus disease occurs disproportionately in males. Infection within the first two weeks of birth can cause devastating and potentially fatal disease. In this population, death usually results from overwhelming
liver failure ormyocarditis , rather than infection of the central nervous system. Older children and adults have a better prognosis. Myocarditis is the most frequent complication in adults.Echovirus infections can occur in people of all age groups. However, as we get older, there is increased production of specific
antibodies to the echovirus. Several studies performed duringepidemics show that infants become infected at notably higher rates than older children and adults.Cause of infection
Causes of echovirus infections can be placed in several categories. Main causes of infection are from overcrowded conditions such as the poor districts of a city and poor
hygiene . Echoviruses are transmitted person-to-person; the fecal-oral route is the predominant mode, although transmission sometimes occurs via respiration of oral secretions such assaliva . Indirect transmission occurs through numerous routes, including via contaminated water, food, andfomite s (inanimate objects). Contaminated swimming and wading pools can also transmit the virus. Also, there are well-documented reports of transmission via the contaminated hands of hospital personnel.Treatment
No specific treatment for echovirus infection is currently available. Care is directed at relief of symptoms. The anti-viral drug
pleconaril interferes with the binding of the echovirus particle to the cell membrane and the drug also hinders the uncoating ofvirions by attaching itself to the viral protein capsid. The pharmaceutical company,ViroPharma Incorporated , ended development of pleconaril in 2004.In popular culture
Echovirus 11 was the cause of an epidemic in a maternity ward in the "House MD" episode "Maternity".
References
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