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any of a group of viruses associated with various diseases including viral meningitis and mild respiratory disorders and diarrhea in newborn infants

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/08 16:58:28」(JST)

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An ECHO (Enteric Cytopathic Human Orphan) virus, is a type of RNA virus that belongs to the species Enterovirus B, genus Enterovirus of the Picornaviridae family.^[1] 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 faeces of asymptomatic children early in the 1950s, just after cell culturing had been developed. The echo– part of the name was originally an acronym 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.^[2]

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.^[3] Infection of an infant with this virus following birth may cause severe systemic diseases, and is associated with high infant mortality rates. The echovirus can mimic symptoms caused by other common bacterial and viral infections.

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-stranded RNA. This RNA has a length of approximately 7.5 kilobase (kb), contains an RNA replicase, viral-coded proteins, and a single polyprotein that is responsible for the formation of structural proteins and other proteins necessary for cellular replication. The structural proteins determine host range and play a very important role in delivering the RNA genome into the cytoplasm of new host cells.^[3]

Some viral replication of an echovirus occurs in the nasopharynx after infection and then spreads to regional lymph nodes. However, most viral particles are swallowed and they reach the lower gut tract, where the virus is presumed to bind to specific receptors. The virus then spreads to the lower intestinal 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 the central nervous system, liver, spleen, bone marrow, heart and finally the lungs. 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.

Symptoms and diagnosis

Echovirus disease occurs disproportionately in males and children. 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 or myocarditis, 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, like the other Enteroviruses Coxsackievirus A and B, typically causes a mild, nonspecific illness with a low fever. Echovirus may also produce a rash that spreads from the face down to the neck, upper extremities, and chest. Laboratory diagnosis is made with acute and convalescent titers of serum antibodies to Echovirus.

Cause of infection

Causes of echovirus infections (Acute meningitis) 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 as saliva. Indirect transmission occurs through numerous routes, including via contaminated water, food, and fomites (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 of virions by attaching itself to the viral protein capsid.^[3]

References

^ Ryan KJ; Ray CG, ed. (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. pp. 537–9. ISBN 0-8385-8529-9.
^ Yin-Murphy M, Almond JW (1996). Baron S; et al., eds. Picornavirues. in: Baron's Medical Microbiology (4th ed.). Univ of Texas Medical Branch. ISBN 0-9631172-1-1.
^ ^a ^b ^c ped/629 at eMedicine

UpToDate Contents

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1. エンテロウイルスおよびパレコウイルス感染の臨床症状および診断 clinical manifestations and diagnosis of enterovirus and parechovirus infections
2. 関節炎の原因となる特定のウイルス specific viruses that cause arthritis
3. ウイルス性筋炎 viral myositis
4. エンテロウイルスおよびパレコウイルス感染症の疫学、病因、治療、および予防 epidemiology pathogenesis treatment and prevention of enterovirus and parechovirus infections
5. 小児における非定型性発疹 atypical exanthems in children

English Journal

Recombination and evolutionary dynamics of human echovirus 6.

Cabrerizo M1, Trallero G, Simmonds P.Author information 1Enterovirus Unit, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain.AbstractEnterovirus (EV) infections are associated with a wide array of often severe disease presentations including aseptic meningitis, encephalitis, and acute flaccid paralysis. Surveillance for polioviruses and other EVs is therefore important as a public health measure both for patient management and epidemiological studies. From 1988 to 2008, echovirus (E) 30 was the predominant genotype in Spain (33.7% of the total typed EVs). E6 was also endemic throughout this period although isolated less frequently (12.5%). In 2009, however, a substantial increase in the incidence of E6 was detected (60%), displacing E30 type (2%). To investigate the evolution and recombination in the epidemiology and transmission of E6 in Spain, a genetic analysis in VP1 and 3Dpol regions of 67 Spanish strains collected during the period 2004-2010 was performed. All VP1 sequences clustered monophyletically in the assigned genogroup C, subgroup 9, currently the predominant circulating strains identified in Europe and elsewhere in the last 10 years. 3Dpol sequences were interspersed with other species B EVs resulting from several recombination events that generated at least 12 different recombinant forms (RFs) among study samples. These showed typically minimal divergence in VP1. The co-circulation of different lineages of E6 in the same geographical area associated with its mainly endemic pattern of transmission may have contributed to the extremely short estimated half-life of E6 RFs (0.87 years). This pattern contrasts markedly with other species B EVs and EV71 where VP1 lineage expansion and extinction occurred in step with defined recombination events and periodic changes in incidence.
Journal of medical virology.J Med Virol.2014 May;86(5):857-64. doi: 10.1002/jmv.23741. Epub 2013 Sep 23.
Enterovirus (EV) infections are associated with a wide array of often severe disease presentations including aseptic meningitis, encephalitis, and acute flaccid paralysis. Surveillance for polioviruses and other EVs is therefore important as a public health measure both for patient management and ep
PMID 24114692

Coxsackievirus A9 Infects Cells via Nonacidic Multivesicular Bodies.

Huttunen M1, Waris M, Kajander R, Hyypiä T, Marjomäki V.Author information 1Department of Biological and Environmental Science and NanoScience Center, University of Jyväskylä, Jyväskylä, Finland.AbstractCoxsackievirus A9 (CVA9) is a member of the human enterovirus B species in the Enterovirus genus of the family Picornaviridae. According to earlier studies, CVA9 binds to αVβ3 and αVβ6 integrins on the cell surface and utilizes β2-microglobulin, dynamin, and Arf6 for internalization. However, the structures utilized by the virus for internalization and uncoating are less well understood. We show here, based on electron microscopy, that CVA9 is found in multivesicular structures 2 h postinfection (p.i.). A neutral red labeling assay revealed that uncoating occurs mainly around 2 h p.i., while double-stranded RNA is found in the cytoplasm after 3 h p.i. The biogenesis of multivesicular bodies (MVBs) is crucial for promoting infection, as judged by the strong inhibitory effect of the wild-type form of Hrs and dominant negative form of VPS4 in CVA9 infection. CVA9 infection is dependent on phospholipase C at the start of infection, whereas Rac1 is especially important between 1 and 3 h p.i., when the virus is in endosomes. Several lines of evidence implicate that low pH does not play a role in CVA9 infection. The infection is not affected by Bafilomycin A1. In addition, CVA9 is not targeted to acidic late endosomes or lysosomes, and the MVBs accumulating CVA9 have a neutral pH. Thus, CVA9 is the second enterovirus demonstrated so far, after echovirus 1, that can trigger neutral MVBs, which are important for virus infection.
Journal of virology.J Virol.2014 May;88(9):5138-51. doi: 10.1128/JVI.03275-13. Epub 2014 Feb 26.
Coxsackievirus A9 (CVA9) is a member of the human enterovirus B species in the Enterovirus genus of the family Picornaviridae. According to earlier studies, CVA9 binds to αVβ3 and αVβ6 integrins on the cell surface and utilizes β2-microglobulin, dynamin, and Arf6 for internalization. However, t
PMID 24574401

An outbreak of echovirus 33 in schools in China in 2013.

Tan X1, Gao L, Ma X, Nie J, Zhan D, Zhang B, Liu Y, Liu F, Xu W.Author information 1Key Laboratory of Medical Virology of Ministry of Health, Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.AbstractEchovirus 33 (E33) has been infrequently detected and is less frequently associated with clinical diseases when compared with other types of enteroviruses (EVs) in China. An outbreak of E33 was identified in four schools in Hunan Province, China, in June 2013. For laboratory diagnosis, throat swabs and/or serum specimens were collected from 27 patients. E33 was isolated in cell culture and typed by molecular methods. Complete VP1 gene sequences were determined and analyzed. Specific E33 antibody was measured by virus neutralization testing. From June 3-20, 108 suspected cases were reported, and 19 were confirmed to be associated with E33 by laboratory testing, with seven virologically confirmed and 12 serologically confirmed cases. The suspected cases were in children aged 3-16 years (mean, 11 years), most of whom (94 %, 102/108) were ≥6 years old. The majority of cases (98 %, 106/108) presented as influenza-like illness (ILI), and two were clinically diagnosed as viral meningitis. Older children aged ≥12 years had a higher hospitalization rate (21 %) than younger children (4 %). A BLAST query of GenBank with the Hunan E33 strain VP1 gene sequence gave a close match to an E33 isolate from Pakistan, based on a partial VP1 gene sequence. Phylogenetic analyses of the complete E33 VP1 gene sequences from our study revealed an independent cluster with nucleotide sequences that diverge from E33 from other countries by >12 %. Due to limited E33 VP1 gene sequence data in GenBank and passive EV surveillance in China and most other parts of the world (excepting hand, foot, and mouth disease surveillance in Asia), the approximate origin of Hunan E33 could not be determined.
Archives of virology.Arch Virol.2014 Apr 3. [Epub ahead of print]
Echovirus 33 (E33) has been infrequently detected and is less frequently associated with clinical diseases when compared with other types of enteroviruses (EVs) in China. An outbreak of E33 was identified in four schools in Hunan Province, China, in June 2013. For laboratory diagnosis, throat swabs
PMID 24696270

Japanese Journal

Laboratory and Epidemiology Communications : High Incidence of Human Echovirus Type 3 among Children in Osaka, Japan during the Summer of 2010

Sekiguchi Jun-ichiro,Kubo Hideyuki,Kaida Atsushi [他]
Japanese Journal of Infectious Diseases 64(6), 533-535, 2011-11
NAID 40019126201

Laboratory and epidemiology communications: Endemic transmission of echovirus 30 in Toyama, Japan in 2010 is verified by environmental surveillance

Iwai Masae,Horimoto Eiji,Obara Mayumi [他]
Japanese Journal of Infectious Diseases 64(2), 165-167, 2011-03
NAID 40018775778

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★リンクテーブル★

リンク元	「エコーウイルス」「coxsackievirus B」「human enterovirus B」「Coxsackie B virus」
拡張検索	「echovirus infection」

「エコーウイルス」

ECHO virus
Virus classification
Group:	Group IV ((+)ssRNA)
Order:	Picornavirales
Family:	Picornaviridae
Genus:	Enterovirus
Species:	Enterovirus B
Subtype
	ECHO virus