2.1 Principles Of Communicable Disease Control And Outbreak Management

Question 1

What are the main routes of transmission of disease between people?

Answer 1

Droplet spread 
Aerosol
Faecal-oral
Direct contact
Vector borne
Blood borne 
Fomites

Question 2

Give examples of disease that spread via droplet or aerosol spread?

Answer 2

Influenzae
Measles
Meningococcal infection
COVID-19

Question 3

Give some examples of faecal-oral route diseases?

Answer 3

Typhoid
E.coli.
Hepatitis-A

Question 4

Give some examples of diseases that spread via direct contact

Answer 4

Scabies 
Impetigo - topical staphylococcal skin infection 
Nits
Cold sore
STIs generally

Question 5

Give some examples of vector borne disease transmission

Answer 5

Malaria
Dengue
Lyme disease
Leptospirosis 
Rabies

Question 6

Give some examples of diseases that spread via blood borne transmission

Answer 6

HIV
Hepatitis B
Hepatitis C

Question 7

Give some examples of blood borne transmission

Answer 7

Receiving contaminated blood products
IV drug use
Transmitted during pregnancy / labour
Sexual contact

Question 8

What is a fomite?

Answer 8

A non living object that transmits disease causing pathogens e.g door knobs or tap handles.

Question 9

What is the epidemiological triangle?

Answer 9

A simple diagram showing the different factors that determines a diseases spreadability. Considers the agent itself, the host and the environment.
The agent is the disease causing thing such as the bug
The environment must by suitable for spread and facilitates the bug moving from the host to a new carrier.
The host is an ill person or asymptomatic carrier.

Question 10

What is the chain of infection?

Answer 10

Host
Person to person spread
Reservoir
Portal of exit
Agent 
Mode of transmission
Portal of entry 
Host

Question 11

What measures can be used to kill or inactivate the agent at source?

Answer 11

Antibiotics
Decontamination
Disinfection
Sterilisation
Heat treatment

Question 12

What measures can be taken to interrupt the pathway of transmission?

Answer 12

Isolation
Environmental hygiene
Personal hygiene
PPE

Question 13

What measures can be taken to protect the receptor host?

Answer 13

Isolation
Immunisation - of vulnerable, contacts, cocoon
Chemoprophylaxis

Question 14

What are the key steps necessary for disease transmission?

Answer 14

Infectious agent
Source of infection
Available pathway for disease transmission
Population with susceptible people in it

Question 15

What is an outbreak?

Answer 15

Two or more linked cases of an infection. May be Linked by time, place or person
Or
An increase in cases of a disease over and above the normal background rate of that disease

Question 16

What is meant by a cluster of a disease?

Answer 16

An observed (real or perceived) aggregation of cases
grouped in a single time period or setting and
suspected to be above the expected level. Not necessarily a proven link between the cases.

Question 17

How is an epidemic curve plotted?

Answer 17

Number of cases on the y axis

Time along the x axis

Question 18

What is a point source outbreak?

Answer 18

A single rapid rise in cases resulting in a peak. Followed by an equally rapid fall in cases. Implies that there is a single source of the infection that was expose to a large number of people over a short period of time

Question 19

Give an example of the causation of a point source outbreak

Answer 19

Food borne outbreaks associated with big events

Question 20

What is an extended outbreak?

Answer 20

When there is a more gradual increase of infections over time and a more gradual decrease. Flatter and wider curve than a point source outbreak. Longer lasting source.

Question 21

Give an example of a causation of an extended outbreak

Answer 21

A contaminated water source.

Question 22

What is a propagated outbreak?

Answer 22

Outbreaks where there is sustained person to person transmission. Many clusters occurring and outbreak lasts a long duration.

Question 23

What is meant by R0?

Answer 23

A basic reproduction number of the virus. Is an integral factor of the organism of the virus. Refers to given a 100% susceptible population, how many secondary cases would a primary case produce.

Question 24

What is meant by the R number?

Answer 24

The net reproduction number or the effective reproduction number
How many people is truth a case will go on to infect.

Question 25

What is a superspreader?

Answer 25

Someone who spreads the infection to a degree far more so than the r number

Question 26

What are the 9 steps of investigating an outbreak?

Answer 26

1. Establish a case definition 2. Confirm cases are real 3. Determine background rate - is this really an outbreak 4. Case finding (active) 5. Describe cases in time, place and person - ask lots of questions 6. Plot your epidemic curve 7. Generate your hypothesis 8. Test your hypothesis (usually with case control model) 9. Generate conclusions

Question 27

When dealing with an outbreak, what procedures should be done whilst investigating to protect the population?

Answer 27

Take samples Instigate control methods Convene an outbreak control group Communication

Question 28

When describing cases, what factors must be considered?

Answer 28

``` Demographics Symptoms and TIMING Travel/Other exposures including food Immunisations Ethnic/Cultural/Religious Background ```

Question 29

What is the incident management team/ outbreak management team?

Answer 29

A multidisciplinary team than help investigate and control outbreaks.

Question 30

What group members should be included in an outbreak control team?

Answer 30

``` Health protection specialist from local HPT Screening and immunisation team representative Education representative School nurse/ team leader GPs Local DPH Local clinical commissions groups Communication leads Acute trust representative ```

Question 31

What are the legal frameworks that help with control of infectious diseases?

Answer 31

Notifiable infections/agents Control of Disease Act Environmental Health Regulations International health regulations

Question 32

At what point can you declare that an outbreak is over?

Answer 32

When there has been no new cases within twice the time of the incubation periods from the date of the last confirmed case. Or When the background rate of infection returns to normal/ below expected value

Question 33

What should be done when an outbreak is over?

Answer 33

Declare it as over Debrief - both hot and cold Contingency plan

Question 34

Notifiable diseases are not he only things that should be notified according to the law. What other things should be notified to the local council?

Answer 34

Any infection which presents, could present or could have presented significant harm to human health (for example, varicella zoster exposure in pregnant or immunocompromised people) - Any relevant contamination (e.g. chemical or radiological) which presents, could present or could have presented significant harm to human health

Question 35

Whether a notification should be considered urgent or not depends upon a number of factors. What do you think these factors might be?

Answer 35

The type of disease - urgent if highly contagious. Need to put in control measures swiftly to reduce likelihood of outbreak