Heath protection and Epidemiology of infectious disease

Question 1

Define incubation period

Answer 1

Time between exposure to pathogen and presentation of symptoms

Question 2

What is the aim of health protection?

Answer 2

Protect the public from communicable diseases and health risks associated with non-communicable environmental hazards

Question 3

Name 4 agencies involved with control of communicable disease

Answer 3

HPA

FSA

Local authorities

Department of health

PCTs

Water companies

Question 4

What is the epidemiological triad?

Answer 4

Model of the cause of infectious disease

Agent factors (microorganism)

Host factors (susceptibility, genetic, socioeconomic, lifestyle)

Environmental (climate, surroundings, services)

Question 5

Define reservoir

Answer 5

Where the agent lives, grows and multiplies. Can be human, animal or environment

Question 6

What are the factors involved in a chain of infection?

Answer 6

Reservoir of agent

Portal of exit

Mode of transmission

Portal of entry

Susceptibility of the host

Question 7

Name two direct modes of transmission of infection

Answer 7

Touch

Droplet (airborne, faecal-oral)

Question 8

Name three indirect modes of transmission of infection

Answer 8

Vehicle: food, fomites, blood

Vector: biological, mechanical

Airborne: dust, aerosols

Question 9

What are the key concepts in the control of infection?

Answer 9

Control the source

Control transmission

Protect susceptible individuals by immunisation or prophylactic antibiotics

Question 10

Name three global health protection issues

Answer 10

Malaria

HIV/AIDs

TB

Hepatitis C

Dengue

Ebola

Question 11

Describe the factors that influence global health protection

Answer 11

Travel and migration: increase in international trade and migration affect incidence of certain disease e.g. TB, malaria, HIV, enteric fever more common in migrants. Human behaviour and lifestyle affects spread of disese e.g. STDs, Hepatitis

Change in environment and land use: acess to inaccessible land increases exposure to animals and insects carrying disease e.g. ebola, lassa fever

Climate change: affects vector breeding and insect/animal resovoirs/habitat.

Microbial adaption: antibiotic resistance

Question 12

What is surveillance?

Answer 12

Continued monitoring of the occurence and spread of a disease

This is then interpreted and results are disseminated to relevant bodies so action can be taken.

Question 13

What are the benefits of surveilance?

Answer 13

Ongoing

Consistent

Timely

Accurate

Complete

Question 14

What is the purpose of surveillance?

Answer 14

Individual case management to prevent spread

Measures changes in incidence

Tracks changes in occurence and risk factors

Target interventions

Evaluate control measures

Provide information for emerging new infections of public health importance

Question 15

Why do epidemics occur?

Answer 15

Increase in amount or virulence of an agent

Introduction of agent into a new setting

Enhanced mode of transmission

Increase in host susceptibility

Increase in host exposure

New portals of entry

Question 16

How are outbreaks defined?

Answer 16

Two or more linked cases

Increase in background rate

Single case of rare or serious disease

Microbial or chemical contamination of food or water.

Question 17

Why is it important to investigate outbreaks?

Answer 17

To reduce primary cases

Reduce secondary cases

Prevent similar outbreaks in future

Prosecution/compensation

Research

Teaching

Question 18

What are the immediate control measures for an outbreak?

Answer 18

Controlling the source of infection

Interruption transmission

Protecting those at risk

Question 19

Define sensitivity

Answer 19

How often a test is positive in a person who actually has the disese being tested

Question 20

Define specificity

Answer 20

How often a test is negative in people who don’t have the disease being tested

Question 21

Positive predictive value

Answer 21

True positives/ true positives and false positives

Question 22

Negative predictive value

Answer 22

True negatives/ true negatives and false negatives

Question 23

What is descrptive epidemiology

Answer 23

Describes disease in context of time, person and place

Question 24

Define latent period

Answer 24

Inactive period between exposure to an infection and subsequent illness

Question 25

Describe the steps involved in the management of outbreak investigation

Answer 25

Detection: case reports, complaints, surveillane

Confirming the diagnosis: clincal /lab diagnosis. Quantify extent of outbreak

Control measures: control the source, interrupt transmission, protect those at risk

Question 26

Define infectious period

Answer 26

The period of time and infected individual is able to transmit a pathogen to a susceptible host