Lecture 9: Epidemiology of Infectious diseases

Question 1

What is the disease triangle, what does it infer

Answer 1

viurs, host, environment
- all factors infleunce eachother
- combined effects infuence risk

Question 2

outbreak

Answer 2

sudden increase in occurence

Question 3

pandemic

Answer 3

outbreak that has spread across a wide region

Question 4

Endemic

Answer 4

cases at a baseline level in a geographic area

Question 5

Pathogen

Answer 5

microbe able to damage the host

Question 6

Infection

Answer 6

colonisation/invasion of a host by a pathogen

Question 7

Opportunistic pathogen

Answer 7

microbe that takes advantage of an opportunity to cause infection

Question 8

What is the host range

Answer 8

• he breadth of organisms a parasite is capable of infecting
• host-restricted, broad host range

Question 9

List some sources of pathogens

Answer 9

self and others, food and drink, environemnt, air (fomites), insects and animals

Question 10

List the some modes of transmission

Answer 10

airborne, droplet, drinking and eating, bodily fluid, direct contact, isect bite, surgery

Question 11

explain how drugs and genetics play a role in pathogenesis

Answer 11

• risk factors
• can increase susceptibility to disease or influence how disease plays out

Question 12

List some risk factors of disease

Answer 12

age, exising/underlying medical conditions, gentics, hospital/surgery, medication, contact

Question 13

what is R0 and what does it depend on

Answer 13

• measure of infectiousness (proprotional)
• how many people does 1 case infect
• R0 > 1 –> exponential spread
• depends on organism, dose, route of transmission

Question 14

What is Reff

Answer 14

Effective R
takes into account public health measures like vaccination

Question 15

Incubation period

Answer 15

time between exposure to infectious microbe and onset of symptoms

Question 16

what does the incubation period depend on?

Answer 16

• organism
• infecting dose
• immunity of the person
• person may be infectious or not depending on organims

Question 17

clinical disease rate

Answer 17

proportion of infected people who develop disease

organism, exposure, immunity of the person

Question 18

Infection fatality rate

Answer 18

estimated deaths as a proportion of all infected

Question 19

case fatality rate

Answer 19

deaths as a proportion of confirmed cases

Question 20

what does fatality rate depend on

Answer 20

organism, infecting dose, immunity of the person, treatments

Question 21

immuntiy rate

Answer 21

number of people immune to reinfection

Question 22

Explain the pathogenesis of Ebola

Answer 22

1. Attachment - glyocoprotein binds to TIM-1receptor molecules
2. Penetration - viral envelope fuses with the host cell
3. Uncoating - release of nucleic acid. polymerase protein turns it into mRNA template
4. Translation - mRNA uses host cell system to replicate vital DNA
5. Budding - New vopies of virus bud from cells

Question 23

How do you get the Ebola virus?

Answer 23

direct contact wit
1. bodily fluids of a person who is sick or has died from Ebola
2. Objects contaminated with the virus
3. Infected animals

Question 24

How is Ebola transmitted/spread

Answer 24

only spreads when people are sick - must be symptomatic to spread disease

Question 25

Mortality rate Ebola

Answer 25

25-100%

Question 26

What three areas had the largest case and deat rate in the 2014 outbreak?

Answer 26

Guinea, Liberia and Sierra Leone

Question 27

What is the treatment for Ebola

Answer 27

Monoclonal antibodies - neutralise virus