Pandemics

Question 1

What type of genetic change causes a pnademic

Answer 1

large shift in the influenza virus (genetic shift).

Question 2

WHat animals are involved in a pandemic and how?

Answer 2

Swine mixes viruses from humans, avians and swine, (all three can infect the swine.)

Question 3

Once in the popualtion, what happens to the pandemic virus

Answer 3

gwenetic drift in order to change enough to infect and spread. Becomes less pathogenic over time

Question 4

What makes a pandemic strain of influenza? (6)

Answer 4

1. Little prior immunity in the population
2. High replication of the virus
3. Efficient infection of the upper and lower respiratory tract
4. Wide scale destruction of epithelial cells in the respiratory tract
5. Cytokine storm leading to more damage to the lungs and lots of infiltrating cells
6. Good conditions for bacterial growth (dead cells and edema provide bacterial nutrients)

Question 5

What linkage does a normal human viral HA bind on a human cell?

Answer 5

sialic acid α2-6 linkages

Question 6

What linkage does a pandemic viral HA bind on a human cell

Answer 6

both the α2-3 linkage and α2-6 linkage of sialic acid

Question 7

What linkages are found in the LRT? URT?

Answer 7

α2-3 linkage of sialic acid is found in the LRT

α2-6 linkage in URT

Question 8

What needs to happen for an influenza virus to be Infectious?

Answer 8

viral HA needs to be cleaved by cellular proteases

Question 9

How did the 1918 virus make itself more infectious through mutations

Answer 9

allowed more proteases to cleave the HA

allowed for more efficient cleavage of HA

Question 10

What role does low glycosylation of HA have on a strain’s pathogenesis

Answer 10

low glycosylation = less binding by antimicrobials (like surfactant protein D)

Question 11

What role does high glycosylation of HA have on a strain’s pathogenesis

Answer 11

high glycosylation = masks HA from neutralizing antibodies

Question 12

Did the 1918 flu have low or high glycosylation

Answer 12

low

Question 13

What is, and what does PB1-F2 do? (3)

Answer 13

it is a vrulence factor that

1. cuases CD8 and alveolar macrophage apoptosis
2. inflammatory increase (cytokine storm)
3. Increases infiltrates of lung airways

Question 14

Did 1918 and 2009 have PB1-F2

Answer 14

only 1918

Question 15

What two general things made the 1918 starin so virulent

Answer 15

1918 was able to

1. replicate very efficiently-produce high levels of virus 2. infect both the upper and lower respiratory tract

Question 16

why is URT and LRT infection important to a virus

Answer 16

URT = efficient spread
LRT = destroys epithelial cells to allow secondary bacterial infections

Question 17

What does HPAI, LPAI mean?

Answer 17

High/Low Pathogenic Avian Influenza- based on ability to kill chickens- has nothing to do with humans

Question 18

What is the mortality rate of H5N1 avian flu

Answer 18

53% case fatality rate

Question 19

Is H5N1 HPAI or LPAI

Answer 19

HPAI

Question 20

What is case fatality rate of H7N9

Answer 20

40%

Question 21

is H7N9 HPAI or LPAI

Answer 21

LPAI- doesn’t cuase a lot of death in birds but does in humans

Question 22

What two mutations allow avian influenza to be transmissible from human to human

Answer 22

1. avian NA needs to be able to cleave the alpha 2-6 sialic acid linkage
2. PB2-polymerase needs to replicate better at colder temps (birds have higher body temps than humans

Question 23

MERS Case fatality rate

Answer 23

36% CFR

Question 24

SARS cFR

Answer 24

9.6%

Question 25

What population had the highest rate of morbidity with SARS

Answer 25

Older people died at a much higher rate

Question 26

what are the complications arising with SARS infx (4)

Answer 26

1. 20% Diarrhea, 2. abnormal liver function (70-90%), 3. Lymphopenia 70-95% (reduction in CD4 and CD8 T cells) 4. Severe Respiratory Distress (20-30% require intensive care and ventilation)

Question 27

What animal did the SARS virus originate

Answer 27

Infected animals at a Chinese Wet Market: Palm Civets, Raccoon dogs

Question 28

How is SARS tranmistted (2)

Answer 28

Mostly took prolonged close contact and spread respiratory droplets. Some super spreaders who aerosolized (high virus titer)

Question 29

what measure prevents the spread of SARS

Answer 29

N95 respirators

Question 30

What are potential aerosolizers for the virus? (6)

Answer 30

``` Cough-generating procedures Bronchoscopy Sputum induction Intubation and extubation Cardiopulmonary resuscitation Open suctioning of airways ```

Question 31

Transmission of MERS (3)

Answer 31

droplet, contact (vomit, feces, urine), Airborne

Question 32

What complications are there with MERS

Answer 32

ARDS, renal failure, multi-organ failure

Question 33

What population most infected with MERS.

Answer 33

Most infections in adults median age 50,

Question 34

What population most hospitalized with MERS

Answer 34

hospitalizations mostly with people who have chronic comorbidities

Question 35

How is MERS transmitted (3)

Answer 35

bats, camels, super spreading events in health care setting.

Question 36

what animals can be involved in spread of Nipah

Answer 36

pigs, bats, horses,

Question 37

WHat two things diseases does Nipah cause

Answer 37

Causes encephalitis, and sometimes respiratory symptoms

Question 38

Case fatality rate of Nipah

Answer 38

74% CFR

Question 39

What is the unique vector of transmission in Nipah

Answer 39

Bats spread-raw date palm sap (palm wine), to pigs, 50% cases person to person spread

Question 40

MERS: stands for, is what family

Answer 40

Middle East Resp Syndrome, CoV