Lecture 24 - Respiratory viruses

Question 1

true or false, viruses that infect the respiratory system that is not the lungs often kill people

Answer 1

false. viral lung infections can be serious but typically upper respiratory tract infections arent

Question 2

most respiratory viral infections affect?

Answer 2

the upper respiratory tract

Question 3

what is otitis media?

Answer 3

viral infection of middle ear, can be bacterial viral or both simultaneously

Question 4

what are the most common sites of respiratory infections?

Answer 4

sinuses and other air filled spaces such as the middle ear

Question 5

how does the respiratory tract prevent infection?

Answer 5

goblet cells secrete mucus onto respiratory epithelium, cilia beat towards the oropharynx where mucus is swallowed and viruses and bacteria are killed

Question 6

viruses must attach to ___________ _________ cells, then ______ those cells and __________.

Answer 6

respiratory epithelial, enter, replicate

Question 7

how can immune responses cause harm as well as good?

Answer 7

vasodilation and inflammation allows cells to get to site of infection, but fluid can accumulate in the respiratory epithelium and cause it to be swollen
- 2 things causing symptoms

Question 8

how can a virus infection cause otis media?

Answer 8

viral infection causes immune response, which swells the respiratory epithelium, which prevents fluid from draining from middle ear to throat to be swallowed. fluid accumulates in middle ear and bacteria can accumulate

Question 9

why are respiratory virus infections more serious in very young infants?

Answer 9

narrow airways are more easily blocked off, and mucous can accumulate and facilitate bacteria to multiply and thrive

Question 10

why are respiratory virus infections more serious in very old people?

Answer 10

because airways are damages prior to illness, e.g smoking, sam mechanism as children

Question 11

how many people get the flu per year?

Answer 11

1 out of 6 - 15%

Question 12

what are amongst the most common reasons people visit a GP?

Answer 12

upper respiratory tract infections (colds)
acute bronchitis
otitis media
tonsillitis
(aka respiratory viruses are most common reason ppl visit a GP)

Question 13

respiratory tract infections are the most common reason for what prescriptions?

Answer 13

antibiotics, which is normally not helpful.
Otitis media can be bacterial, but often clears on its own, so a lot of wasted antibiotics use

Question 14

streptococcus pneumoniae does what to us?

Answer 14

infects sinuses, fluid accumulation during otitis media and main cause of pneumonia

Question 15

name the four respiratory virus types we will be looking at in this lec

Answer 15

rhinoviruses
coronaviruses
RSV
influenza viruses

Question 16

can a corona virus act on the legs?

Answer 16

no, respiratory viruses only act on respiratory system

Question 17

most sore throats are caused by?

Answer 17

virus infections

Question 18

most patients with respiratory infections dont need antibiotics. why?

Answer 18

because they are mostly caused by viruses

Question 19

corona viruses typically cause what?

Answer 19

colds

Question 20

describe SARS

Answer 20

Severe Acute Respiratory Syndrome
Bat -> Civet -> humans
2002-2003
9% mortality rate,

Question 21

describe MERS

Answer 21

Middle Eastern Respiratory Syndrome Bats -> camels -> humans
2012 -
36% mortality rate

Question 22

who did COVID-19 affect the most and what data proves this?

Answer 22

older people
people under 50 had pretty much zero chance of dying, but people over 80 had a 15% chance of dying

Question 23

how are respiratory viruses transmitted?

Answer 23

aerosols - close
exhalation
cough
sneeze (worst)

Question 24

putting on a mask prevents transmission

Answer 24

true

Question 25

which diagnostic test was done for SARS-CoV-2 originally?

Answer 25

PCR, detects specific regions RNA unique to SARS-CoV-2 from a sample of mucous from the nose or throat, and is amplified to be detected

Question 26

what was the improved diagnostic test for SARS-CoV-2?

Answer 26

the rapid antigen test detects a protein of SARS-CoV-2 from mucous of nose or throat by binding to antibodies with gold particles attached on the blotting paper strip

Question 27

how was the covid-19 vaccine developed to work?

Answer 27

mRNA coding for spike protein, which develops neutralising IgG antibodies against it to prevent infections in the future

Question 28

how efficient was the pfizer vaccine?

Answer 28

95%

Question 29

how does the influenza virus replicate?

Answer 29

spike proteins bind respiratory epithelium receptors, is endocytosed, virus releases RNA into cell where it is made into new influenza proteins and influenza pieces that go out via budding off

Question 30

what are the two spike proteins of the influenza virus?

Answer 30

Haemagluttinin (HA/H) Neuraminidase (NA/N)

Question 31

how many RNA molecules are in influenza viruses?

Answer 31

8

Question 32

what does haemagluttinin do?

Answer 32

sticks to surface of cell

Question 33

which part of the influenza virus is different for each strain?

Answer 33

the heamagluttinin HA/H surface protein

Question 34

how does the haemagluttinin change between strains

Answer 34

genetic drift: due to gradual mutation accumulation withing the genes, causing minor changes in HA and NA shift: two virus strains simultaneously infecting the same cell can assort genes, causing major changes in HA and NA

Question 35

what is the consequence of the mutating heamogluttinin

Answer 35

antibodies that can bind one can't bind the other - this is why 1 in 6 of us get it every year, because we need new antibodies more often

Question 36

which mechanism of change in influenza viruses has led to flu outbreaks in the past and why?

Answer 36

shift: rapid change in HA and NA - spanish flu

Question 37

what was the swine flu of 2009?

Answer 37

sudden outbreak of the flu due to a shifted influenza virus strain

Question 38

describe influenza

Answer 38

- lasts 5-6 days - 3-4 days in bed, off work - morbidity and mortality especially in young and elderly - episodes of illness every approx 7 years

Question 39

describe the pathology of influenza in term of epithelium

Answer 39

resp. epithelium gets infected, cilliated cells die off, becoming smooth and grow back after a few days

Question 40

how do we recover from the flu?

Answer 40

immunity to the HA of one flu strain

Question 41

how quick does drift vs shift work?

Answer 41

drift can mean we get infected about once every 7 years Shift can mean we are immediately susceptible to new influenza

Question 42

what make up influenza virus vaccines?

Answer 42

fragments of the spike proteins of different strains

Question 43

how can we diagnose influenza?

Answer 43

PCR virus isolation on cell cultures serology detection of antigens clinical presentation (symptoms?)

Question 44

how quickly are antibodies to the influenza HA and NA surface proteins formed?

Answer 44

10-14 days post infection, and are enhanced if there is a previous infection with similar strain

Question 45

true or false, B cell memory against surface proteins for influenza viruses persist for life after one infection

Answer 45

true

Question 46

what is the most effective treatment for influenza?

Answer 46

Oseltamivir = 'tamiflu'

Question 47

what type of virus is the most common cause of the common cold?

Answer 47

rhinoviruses (type of picoRNAvirus)