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The first human orthoreovirus was isolated
in 1953 from a rectal swab collected from a healthy child. Later 3 serotypes
were identified which were designated as reovirus and categorized under the
Reoviridae family. Later it was discovered that the 3 serotypes share a common
group antigen as detected by complement fixation. The name reovirus was proposed
originally by Sabin in 1959 to reflect the fact that viruses of this group had
been isolated from the respiratory and enteric tracts and were orphan (reo)
viruses without known associated disease.
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Viral Characteristics
Reoviridae enters the cell through endocytosis. Early
transcription of the dsRNA genome by the viral polymerase occurs inside the
subviral particle. The 10-12 segments of the genome are transcribed and
translated at different frequencies. RNA is transcribed conservatively with only
(-)sense strands being used as a template to synthesize the (+)sense strands
which are capped inside the viral core and are not polyadenylated. The mRNAs
leave the core and are translated in the cytoplasm. Secondary transcription
takes place in the cytoplasm leading to uncapped (+)sense strands which serve as
templates for (-)strand synthesis.
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The pathonegicity of reoviruses with human diseases
has not been clear. Mostly reoviruses are known to be associated with childhood
diarrhea. Reoviruses cause many inapparent infections because most people have
serum antibodies by early adulthood. Antibodies also are present in other
species. All 3 types have been recovered from healthy children, from young
children during outbreaks of minor febrile illness, and from children with
diarrhea or enteritis. Human volunteer studies have failed to demonstrate a
clear cause-and-effect relationship between reoviruses and human illness.
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http://www.embl-hamburg.de/~tucker/research/Orbivirus.html
Gholamreza Rasouli, MD
John
W King, MD. Reoviruses.
July 6, 2005.
http://www.emedicine.com/med/topic2007.htm#section~medication
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