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Respiratory Viruses
Adenoviruses
Coronaviruses
are ssRNA(+), enveloped
viruses and cause the common cold.
Hantaviruses
are ssRNA(ambisense),
segmented, enveloped viruses which are associated with acute respiratory
distress. Tramissission is by the deer mouse via dropping. Incidence increases
in rainy years in SW US.
Orthomyxoviruses
have a ssRNA(-),
segmented genome with an envelope. Groups include influenza
viruses (A, B, C). A&B are more severe (complications include
pneumonia). Incubation time is about 2 days. Major proteins include
hemagglutinin (H), neurominidase (N) and matrix.
Antibodies against H and N are protective to influenza (vacines are based on these
proteins).
More on the Influenza viruses from the CDC
Paramyxoviruses
have a ssRNA(-) genome
and are enveloped. Serotypes include:
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parainfluenza viruses which cause
bronchiolitis and pneumonia in infants in the hospital setting.
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mumps contains both a fusion
factor and a hemogluttin (HN) glycoprotein. Immunity is life long.
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Respiratory syncytial virus (RSV)
cause bronchiolitis and pneumonia particularly in infants and can also cause
croup. RSV has no HN protein but it does have a Fn protein which causes
syncytia.
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human metapneumovirus caues
bronchiolitis and pneumonia, mainly in children under 2. 100% of people will
be seropositive by 10.
Picornaviruses
are ssRNA(+), naked
virion viruses. Members which cause respiratory distress include:
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enteroviruses are spread mainly
by the fecal-oral route (as with contaminated swimming pools). They are easy
to transmit and can last up to 4 months in feces. Symptoms range from mild to
life threatening. Enteroviruses include the coxsackieviruses and
polioviruses for which the incidence has declined worldwide due to the
Salk and Sabine vacinnes (1955, 1963).
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rhinoviruses There are more than 100 serotypes. Huamn rhinovirus (HRV) infection is one of the most fequent cuases of the common cold. In HRV infection, pathogen-specific immune respones are hindered in the respiratory tract, making patients susceptible to secondary bacterial infection and leading to bronchitis and pneumonia. This has been attributed to a functional cahnge in DCs, which dependent on PD-1-PD-L1 and sialoadhesin.
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