Respiratory Viruses I Flashcards
What is the most common route of viral infection?
Respiratory inhalation
What is the genomic structure of influenza virus?
Negative RNA, segmented, enveloped
Is influenza virus enveloped or not?
Enveloped
What are the signs of influenza infection?
- Sudden fever
- Cough
- Nasal congestion
- Head and muscle aches
- Fatigue
- Diarrhea (often in infants)
What is the main type of influenza virus causing disease in humans?
Type A
What can be a devastating effect of influenza?
ARDS
What viruses are destroyed by soaps?
Enveloped virions are destroyed by common hand soaps.
What are the H and N in the influenza strains?
They are surface proteins.
H - hemagglutinin
N - neuraminidase
How many RNA strands does influenza have?
8
What protein allows influenza to adhere in the lungs?
Hemagglutinin
Where does influenza replicate?
Nucleus - this is in contrast to other RNA viruses which are ALL in the cytoplasm (except influenza and retroviruses)
What vaccines are available for influenza?
- Live-attenuated virus
- Killed virus
How does antigen drift occur in influenza?
- Influenza viruses replicate through RNA intermediates.
- RNA-dependent RNA replication is error-prone.
Point mutations, usually in regions encoding HA antibody epitopes, can change virus structure and antigenicity leading to viruses that may cause epidemics. This is referred as “genetic drift”
What can cause antigen shift and how is this different than drift?
Shifts are greater changes than drift.
RNA segment reassortment can change virus structure, antigenicity and function dramatically, leading to reassortant viruses that may cause pandemics. This is referred as “genetic shift”.
Amantidine MOA
M2 is blocked and so RNAs will not release from virion proteins. Infection blocked at entry stage.
Neuraminidase Inhibitor MOA
Inhibitor of neuraminidase which normally “unsticks” influenza viruses by cleaving sialic acids from infected cells and from visions - therefore inhibiting them prevents viral dissemination
A cautious 43‐year‐old office worker decided to get vaccinated before the pending (2002‐2003) flu season. Her physician vaccinated her with an intramuscular dose containing: A\Panama (H3N2) and A\NewCaledonia/20/99 (H1N1) and B\Yamanashi. Four weeks after receiving the vaccine, the woman developed a high fever, myalgia, headaches, chills, and a dry, unproductive cough. The cough became progressive with the general symptoms lasting 3 weeks. Her doctor told her that she had the flu even though serological tests showed that the woman seroconverted and had a high vaccine antibody titer. Small changes in the surface glycosylation of the influenza virus are called which of the following?
A. Genetic shift B. Genetic drift C. Camouflage D. Genetic reassortment E. Point mutations
C. Camouflage
What is the main disease caused by rhinovirus?
Common Cold
What virus commonly causes conjunctivitis?
Adenovirus
What does coronavirus cause?
Common Cold - often cause of croup, a bark like cough
How do Ab protect against influenza infection?
The antibodies stick to the HA and prevent HA from binding cells, and/or prevent HA from catalyzing virus‐cell membrane fusion. The higher the affinity of the antibodies for critical parts of HA, the more effective they are at protecting the individual from infection.
