Chapter 23: Orthomyxoviridae and Paramyxoviridae
Terms
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- Generally describe the orthomyxoviruses and paramyxoviruses?
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Ortho - think ordinary flu: the influenza viruses
Para - think parade of distinctly different diseases: parainfluenza, measles, mumps, RSV - Describe the glycoprotein spikes on orthomyxoviruses and their role in viral infection?
- Neuraminidase Activity (NA)which cleaves the cell mucin barrier, while Hemagglutinin Activity (HA) fuses to the sialic acid residues, enabling viral adsorption and penetration.
- What causes the epidemics and pandemics of flu?
- Antigenic drift (small changes in all influenza types) and shift (large changes in type A do to interspecies genetic transfer
- Describe the complications of influenza?
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1. Elderly and immunocompromised can have more serious illness, as virus spreads to cause pneumonia
2. Lowering of the host defenses against many bacteria
3. Children given aspirin can develop Reye's Syndrome - What is Reye's Syndrome?
- Severe liver and brain disease that can develop if a chid with influenza or varicella is given aspirin for the treatment of fever.
- What are some treatment choices for influenza? How do they work?
- Amantadine and rimantidine - prevent the uncoating of influenza A
- List the principles that apply to the paramyxoviruses?
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1. All adsorb to and replicate in the upper respiratory tract
2. Most infections occur in children
3. Viremia can lead to complications - Describe the clinical manifestations of parainfluenza virus infection?
- Cold symptoms to bronchitis and flu-like illness. Children, elderly, and the immunocompromised can also have pneumonia. Children can have croup.
- What is the number one cause of pneumonia in young children, particularly infants?
- Respiratory Syncytial Virus.
- What organs are most often involved in mumps infection?
- "I got bumps caused by mumps!" - parotitis, orchitis (testes)
- Describe measles prodrome?
- Conjunctivitis, swelling of the eyelids, photophobia, high fevers, hacking cough, rhinitis, and malaise.
- What are Koplik's spots?
- Small red-based lesions with blue-white centers in the mouth that appear a day or two before a measles rash.
- Describe the progression and resolution of measles rash?
- Think of the paint can picture - progresses head to toe, resolves in same direction.
- What is the most feared complication of measles?
- Encephalitis