Term
List some respiratory viruses! |
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Definition
- Influenza A, B - Respiratory syncytial virus (RSV) - Parainfluenza viruses (1-4) - Adenovirus - Rhinovirus |
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Term
What is the division between the upper and lower respiratory tract? |
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Definition
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Term
Why was there a significant drop in life expectancy in 1918 in the US and Canada? |
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Definition
There was an influenza pandemic |
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Term
What are some important characteristics of the influenza virus? |
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Definition
- single stranded - RNA virus - enveloped - segmented genome |
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Term
Why is it significant that the influenza virus has a segmented genome? |
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Definition
Because if two strains infect a cell, they can swap genes and create a whole new strain |
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Term
There are really three influenza viruses: _, _ and _ |
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Definition
A, B and C but C tends to be unimportant |
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Term
When are influenza epidemics most common? |
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Definition
they happen on a yearly basis in the winter |
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Term
Which flu (Flu A, B or C) is most important and why? |
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Definition
- Because of its pandemic potential and because it is usually more severe |
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Term
How is influenza typically spread? |
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Definition
- droplets and on soiled hands |
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Term
What two important proteins are on the surface of the influenza virus? |
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Definition
-Hemagglutinin - Neuraminidase |
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Term
What dose hemagglutinin do? |
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Definition
Sticks the virus to cell receptors |
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Term
What does neuraminidase do? |
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Definition
Frees the virus to infect other cells |
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Term
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Definition
- Drifts are small changes/mutations that happen continuously over time as the virus replicates (remember than RNA polymerase is sloppy) - This produces viruses that are different but related so they have similar antigenic properties - So an immune system will typically respond if it is similar - But if it changes enough the immune system will not respond |
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Term
What is the result of drifted viruses? |
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Definition
They contribute to epidemics and an excess number of deaths in the elderly and frail |
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Term
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Definition
- They are reassortments of avian and human viruses - New viruses emerge with new-to-human proteins on their surfaces |
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Term
Drifts can occur in what kind of influenza? (as in a, b or c) |
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Definition
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Term
Illustrate antigenic shift using the "swine flu" |
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Definition
- A duck is the avian host - often the virus is in the GI tract and gets picked up by animals such as pigs that get the duck poop on their noses. - the virus replicates! - the pig can recognize/be infected with both bird and human strains b/c it has two different receptors in its up respiratory tract - The two viruses can mix (aka re-assort) and create a new virus which can then be transmitted to a human host |
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Term
Shifts occur in what kind of influenza? (as in A, B or C) |
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Definition
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Term
In the twentieth century, the world experience three important influenza pandemics... what years, flu A subtype and common names? |
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Definition
1918- H1N1 --> Spanish flu 1957 - H2N2 --> Asian flu 1968 - H3N2 --> Hong Kong |
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Term
Since those three pandemics, the world experienced another in 2009 - name subtype and common name |
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Definition
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Term
How do you get influenza? |
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Definition
- droplet spread - contaminated fingers/hands - fomites - aerosol (controversial) |
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Term
Explain the steps involved in the influenza-host interaction |
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Definition
- Influenza virus is inhaled - Hemagglutinin activity glycoproteins on the surface of influenza virus attach to sialic acid on the surface of cells in the upper respiratory mucosa - primary replication occurs in the lungs - cytokines are released |
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Term
What happens when cytokines are released during the influenza-host interaction? |
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Definition
Cytokines prime surrounding cells by sending out a signal that says something is wrong
but over release of cytokines can lead to muscle aches, issues with the heart and other organs.
Cytokines are what make you feel like crap with the flu |
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Term
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Definition
it doesn't exist
(unless the person is referring to norovirus... but even then apparently that shouldn't be called "The Flu") |
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Term
What are some lower respiratory tract complications associated with influenza? |
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Definition
- Croup and bronchiolitis (in kids) --> there is a direct viral effect, and kids tend to have narrower respiratory tracts - Primary influenza pneumonia |
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Term
What are some secondary bacterial infection complications associated with influenza? |
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Definition
- pneumonia - otitis media (remember it is often viral but in this case it's bacterial) |
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Term
What other complications can you have with influenza? |
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Definition
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Term
What patients get the most influenza complications/benefit most from vaccines? |
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Definition
- Elderly and children - Chronic respiratory disease - Chronic heart disease - Immunosuppression - Haematological disorders - Chronic renal failure - Diabetes mellitus |
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Term
Why are pregnant women at greater risk for flu? |
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Definition
They are pulmonary compromised! In pregnant women the fetus tends to press up against the diaphragm And they are immunocompromised |
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Term
What groups of people (besides pregnant women) are at greater risk in flu pandemics? |
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Definition
- Aboriginal populations (environmental and genetic) - Morbidly obese individuals - Current smokers |
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Term
What type of vaccine is used for seasonal influenza? |
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Definition
Trivalent! 2 type A and 1 type B |
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Term
What kind of influenza vaccine are live attenuated? |
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Definition
the nasal spray form - they are more expensive |
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Term
How efficacious are vaccines for influenza in a) healthy young adults b) elderly c) preventing hospitalization and pneumonia? |
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Definition
a) 60-80% b) 20-30% c) 50-60% |
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Term
How protective are influenza vaccines? |
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Definition
- They are only good when they match with circulating viruses - they are only good if you get re-vaccinated annually |
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Term
How do we treat influenza prophylactically? |
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Definition
We use neuraminidase inhibitors
- Osteltamivir --> influenza A and B - Zamamivir --> influenza A and B |
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Term
How is zamamivir administered? |
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Definition
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Term
Respiratory Syncytial virus is a ____. |
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Definition
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Term
What is important about the RSV structure? |
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Definition
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Term
When do RSV epidemics occur? |
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Definition
- In the winter but also sporadic cases occur throughout the year |
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Term
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Definition
By hand contact
(less common: respiratory route) |
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Term
RSV is responsible for causing ____ in children and the ___ ___ in older kids/adults |
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Definition
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Term
RSV may be fatal for certain children... which ones? |
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Definition
- Those who have heart and lung disease - those who are premature |
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Term
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Definition
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Term
What is Ribavirin used to treat? |
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Definition
It is used to treat severe infections --> RSV
- note: it is expensive and requires hospitalization |
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Term
___ viruses are second only to RSV in infants and young children |
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Definition
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Term
Parainluenza virus infections are often limited to which anatomical area? |
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Definition
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Term
How common is croup with parainfluenza virus? |
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Definition
2% get it! It's formal name is laryngo-tracheo-bronchitis |
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Term
What is the classic sign on a x-ray with Croup? |
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Definition
The "steeple" sign - where there is narrowing of the tracheal air column at the larynx and distension of the hypo pharynx |
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Term
What type of virus is the adenovirus? |
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Definition
it is double stranded and naked (how risqué of you adenovirus) DNA virus |
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Term
How does Adenovirus get transmitted? |
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Definition
- Direct contact or respiratory droplets |
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Term
Adenovirus produces _-_% of pediatric respiratory infections |
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Definition
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Term
What are the clinical syndromes associated with adenovirus? |
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Definition
- Febrile pharyngitis - Lower respiratory infections - Pharyngoconjunctival fever - Conjunctivitis - Diarrhea |
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Term
What kind of virus is Rhinovirus? |
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Definition
- a picornavirus -it is a positive strand RNA virus |
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Term
Where do we primarily see rhinovirus? |
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Definition
In upper airway: - common cold and viral sinusitis |
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Term
On average, how many colds do children have per year? |
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Definition
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Term
Who should be most concerned about enterovirus? |
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Definition
- asthmatics, immunocompromised people and children/babies |
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Term
What type of symptoms are a result of Enterovirus D68? |
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Definition
- mild to severe resp. illness - fever, runny nose, sneezing, cough and body/muscle aches |
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Term
How common is enterovirus in adults? |
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Definition
It can be seen in adults... 25% of cases in past outbreaks |
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Term
How do we diagnose respiratory viral infections? |
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Definition
- Clinical syndromes - Time of year - What's going around in the community - Virus isolation - Virus antigen detection (but not with rhinovirus) - Molecular methods (e.g. PCR) - Serology (not common) |
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Term
How long do otherwise healthy people shed when they have been infected with influenza? What about immunocompromised patients? |
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Definition
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