Global patterns of disease - infectious

Question 1

Why is human evolution slower than viruses and bacteria?

Answer 1

Human generation time (approx 25 yrs) is long, for influenza this is 2-3 days

Question 2

What is the average time taken to develop a new drug?

Answer 2

15 years

Question 3

How long does it take to produce and release a vaccine?

Answer 3

3 months to make but 8 years to trial

Question 4

What are the 3 origins of human infections?

Answer 4

Ancestors
wildlife
livestock

Question 5

What is the percentage of infections spread by zoonosis?

Answer 5

60-70

Question 6

What changes in the world are leading to greater rates of transmission?

Answer 6

Increasing population

Transport- e.g. planes

Question 7

What is epidemiology?

Answer 7

Quantifying the occurrence of disease in population

Question 8

What does case mean in epidemiology?

Answer 8

Person with a disease or health problem

Question 9

What is prevalence?

Answer 9

It is the frequency of disease in a population at a given point in time.

Question 10

How is prevalence calculated?

Answer 10

Number of cases in a population/number of people in a population (at given time)

Question 11

What does prevalence tell us?

Answer 11

The burden of disease in a population

Question 12

What is incidence?

Answer 12

Number of new cases arising over a given time

Question 13

What can prevalence tell us about the risk of developing disease?

Answer 13

How likely you are to develop a disease during a given time period

Question 14

Which measures and tools are needed to estimate incidence?

Answer 14

Define time, total risk population and an accurate test to determine if the person has the disease

Question 15

Why might it be difficult to measure whether a case is new or old?

Answer 15

Chronic conditions - can’t tell whether it is new or old

Question 16

How does incidence influence the development of policies?

Answer 16

One incidence has reached 0, outbreak is over and places can reopen

Question 17

Why might prevalence increase even if incidence stays the same?

Answer 17

If people with the condition are surviving- e.g. use of medication

Question 18

What is mortality?

Answer 18

Number of deaths from a particular disease in a given time

Question 19

If mortality and incidence are equal, what does that mean about the epidemic?

Answer 19

The epidemic is stable

Question 20

How is mortality calculated?

Answer 20

deaths from a disease in a given time/ population at start of time period

Question 21

What is the negative aspect of people with disease living longer?

Answer 21

The transmission increases and incidence increases

Prevalence also increases

Question 22

What is morbidity?

Answer 22

Number of cases of ill health, complications and side effects related to a specific condition over a particular time period.

Question 23

What is the unit for mortality?

Answer 23

number of deaths per 1000 per year

Question 24

What are the leading causes of death?

Answer 24

heart disease
cerebro-vascular disease
respiratory infection
HIV/AIDS
COPD

Question 25

Which country has the highest mortality rate?

Answer 25

Swaziland (30.83) | Sierra Leone, Zambia, Angola, Lesotho also high

Question 26

What causes the majority of deaths in third world countries?

Answer 26

malnutrition

Question 27

Which systems can be used to give scores of morbidity?

Answer 27

APACHE II, SAPS II/III, Glasgow Coma Scale, PIM2, SOFA

Question 28

How can morbidity scores be useful?

Answer 28

Help to decide the type of treatment

Question 29

What are the main types of infectious disease?

Answer 29

``` Lower respiratory infection HIV/AIDS Diarrhoeal disease TB Malaria Measles ```

Question 30

What is the leading cause of death in Sub Saharan Africa?

Answer 30

Infectious disease

Question 31

Why are death rates important?

Answer 31

Important to assess how good the health system is in a country Allows specific public health sectors to be targeted

Question 32

Where did SARS virus originate from, which animal from, and which year was the outbreak?

Answer 32

Origin was the bat is central Asia 2003

Question 33

What was the origin of the West Nile Virus, which year was the outbreak?

Answer 33

Birds (crow/rooks) | 1999

Question 34

Does the West Nile Virus have a high or low infectious rate? | How close is the vaccine to being produced?

Answer 34

High infection rate Vaccine is near clinical trial end

Question 35

Where did MERS virus originate from and where is its incidence high?

Answer 35

Camels | Middle East

Question 36

How does malaria increase its genetic variability?

Answer 36

Mutations and recombination of gametes, plasmid transfer

Question 37

Why is hard to target a vaccine for Plasmodium (causes malaria)?

Answer 37

It has lots of antigens and each one is different

Question 38

Does ebola transmit fast or slow?

Answer 38

slow

Question 39

Why can transmission of ebola be prevented even though it is very contagious?

Answer 39

Symptoms develop before you become infectious so person can be isolated

Question 40

How is ebola transmitted?

Answer 40

Blood, saliva, urine, semen (body fluids) and through contact with contaminated surfaces e.g. soiled cloth

Question 41

What are the public health measures taken in regards to ebola?

Answer 41

- Identify, isolate and follow up contacts of an infected person - Isolation of contacts for 21 days - Border controls are ineffective - House control not used

Question 42

Which animal did Zika virus originate from? | Where did it emerge?

Answer 42

Rhesus monkey | South America

Question 43

What is the risk of infection of Zika virus in pregnant women?

Answer 43

1 in 100 in 1st trimester | 1 in 1000 in whole pregnancy

Question 44

What type of virus is Zika and which animal transmits it?

Answer 44

flavivirus | mosquitoes

Question 45

What other viruses is Zika related to?

Answer 45

Yellow virus Dengue virus West Nile virus (They are all arboviruses)

Question 46

How can Zika Virus be transmitted between people?

Answer 46

Sexually

Question 47

What steps are taken when a new epidemic emerges?

Answer 47

- To indicate emergence of infectious disease - look morbidity/mortality in space and time - Look through databases to find similarities in cases to identify aetiology - Diagnostic tests development - Follow the routes of infection - Ensure the public are aware of new information - avoidance/precaution - Identify ways to reduce mortality/morbidity

Question 48

What is the basic reproductive number (R0)?

Answer 48

average number of secondary cases emerging from a primary one

Question 49

What does it mean if R0 is less than 1 or above 1?

Answer 49

The disease will become extinct if less than 1 | If greater than 1 than means transmission occurs and could lead to an epidemic

Question 50

What factors affect R0?

Answer 50

- incubation period - infectiousness - How long infectiousness lasts - is acquired immunity important

Question 51

What are the prevention and control policies for Influenza?

Answer 51

- Minimise morbidity/mortality - Buy time to wait for vaccine - Minimise duration - Minimise impact on economy Minimise prevalence to stop healthcare collapsing

Question 52

What are some neglected tropical diseases?

Answer 52

Leishmaniasis and African Trypanosomiasis (Protozoan) Schistosomiasis, Lymphatic Filariasis, Onchocerciasis, Dracunculiasis, Ascariasis-Trichuriasis- Hookworm (Helminth) Leprosy, Trachoma, Buruli Ulcer (Bacterial)

Question 53

What does the graph for infection growth look like over time?

Answer 53

increases slowly, then exponential growth. Eventually levels off as the number of people susceptible is very low. Eventually rise due to mutation.

Question 54

Why is it hard to find vaccines against RNA viruses?

Answer 54

No proofreading mechanisms so high mutation rate