Lecture 4

Question 1

What are some controls for mass action incidence

Answer 1

-Reduce k (# of contacts) –> social distancing
- Reduce transmission (pi) –> masking, sanitation/ hygiene

Question 1

What is mass action incidence

Answer 1

Density dependent
B = kpi/N

Question 2

Infection fatality rate

Answer 2

proportion of infectious that lead to death

Question 3

Case fatality rate:

Answer 3

proportion of detected cases that lead to death

Question 4

Which is always bigger case or infection fatality

Answer 4

Case fatality rate

Question 5

How to control R’

Answer 5

gamma –> isolation once youre sick

Question 6

What is a way to control alpha death model

Answer 6

Getting treatment to prevent death and remove from infectious

Question 7

What type of virus causes influenza?

Answer 7

Single-stranded RNA
-orthomyoviridae

Question 8

What determines host immunity for influenza?

Answer 8

Surface proteins, like hemagglutinin and neuraminidase

Question 9

Why would the attack rate be low in the USA for influenza?

Answer 9

Attack rate must be low because R0 is low due to preexisting immunity (vaccines help this)
-we’ve all gotten the flu at some point

Question 10

The spanish flu affected mostly?

Answer 10

young adults

Question 11

Influenza types

Answer 11

A (bird flu), B (human), C (human) , D (humans, cows, pigs)

Question 12

How do influenza pandemics occur

Answer 12

They occur when a new strain for which we have no immunity evolves or one spills over into humans

Question 13

What is a cytokine storm

Answer 13

Cytokine storm is an immune system phenomenon when your immune system sees something unfamiliar and freaks out, leading to an immune response that is dangerous to your own health

Question 14

Why might there be multiple waves of infection?

Answer 14

R0 changes due to behavioral changes (social changes)
-evolution of virus
-R0 can die out and pick up again

Question 15

What is TB caused by?

Answer 15

Bacterium, Mycobacterium tuberculosis

Question 16

What does it mean when we say TB is in the latent phase?

Answer 16

Some level of TB exists in the person, but not enough to show symptoms or be infectious

Question 17

How did we achieve lower TB levels in human populations?

Answer 17

Non-pharmaceutical approaches (decreasing transmission via decreasing contact in dense areas by isolating infected patients), then antibiotics and vaccines

Question 18

What is an SEI model

Answer 18

Latent phase with no recovery
-Susceptible, Exposed, infectious
- Ex: tuberculosis

Question 19

What is HIV? What does it cause?

Answer 19

RNA virus called Human Immunodeficiency Virus which causes AIDs (Acquired Immuno-Deficiency Syndrome)

Question 20

Why don’t the symptoms of HIV appear in a person even though they are infected?

Answer 20

The immune system is able to keep HIV to a low load, but it eventually increases beyond the immune system’s capability leading to symptoms of AIDs

Question 21

What makes HIV and Covid-19 similar?

Answer 21

Like Covid-19, HIV is asymptomatic, so it is able to be spread by individuals who do not know they are infected

Question 22

What kind of model might be appropriate for HIV?

Answer 22

SEI
-Exposed/latent period with no recovery

Question 23

What is theta?

Answer 23

Proportion of infections that occur prior to symptoms or by asymptomatic infection

Question 24

HIV has a low R0, but why is it hard to control

Answer 24

It has a high theta value