Communicable diseases

Question 1

What has Public Health England been replaced with?

Answer 1

UK Health Security Agency
Office for Health Improvement and Disparities.

Question 2

Define communicable disease

Answer 2

Illness caused by infectious microbes normall bacteria or viruses that spread from one individual to another via contact with a contaminated object e.g surface, bite or air droplet

Question 3

What is the key difference between what a communicable and non-communicable disease are?

Answer 3

Communicable - spreads, caused by infective agents or pathogens, highly infectious or rely on vectors. Examples - TB, COVID-19. Can not be inherited. Tend to be acute

Non-communicable - does not spread, caused by allergy, illness, malnutrition, combination of environmental or genetic factors. No infectious agent. Examples include cancer, rickets. Can be inherited. Tend to be chronic

Question 4

What are the key difference in the management of communicable and non-communicable disease?

Answer 4

Communicable - conventional methods, antibiotics etc. Prevent further spread by wearing masks, PPE, hand hygiene, isolation of infected individuals

Non-communicable - conservative or surgical treatment, precautino through regular check ups, maintain proper diet, daily exercise, taking proper sleep and rest.

Question 5

What is the epidemiological triad of infectious disease?

Answer 5

Agent of infection - the pathogen
Environment - mechanism of transmission or reservoir
Host - susceptible to infection

These can all be linked by a vector - acts as a intermediate for survival and transmission.

Question 6

What are the different stages in the chain of infection?

Answer 6

Agent of infection - virus, bacteria parasite etc
Mechanism of transmission - water born, air droplets etc
Portal of entry - cuts in skin, mucous membranes
Susceptible host - influenced by lifestyle, genetics, risk factors
Reservoir of infection - replicates and survives
Portal of exit - vomit, diahorrea.

Question 7

Define pathogenicity

Answer 7

The power of an infective agent to cause disease
Pathogenic or not.

Question 8

Define virulence of a microbe

Answer 8

The ability to produce severe pathological reactions
Measured by the rate of clinical to subclinical disease and the case fatality rate
Describe a property, how nasty, the disease caused by pathogenic microbes is.

Question 9

Define dose of infection (inoculum)

Answer 9

Inoculum - amount of mircobe given to a patient.
MID - The size of the population of the microorganism required to cause disease.
Higher probability of severe disease with higher dose infection.

Question 10

Define viability of the organism (resistance)

Answer 10

The ability of an organism to surive outside the host body.
Ability to persist during transmission between hosts.
A viable organism is living and able to reproduce.

Question 11

How does spore formation affect viability of an organism?

Answer 11

Spore formation - maintains viability for a long period in unfavourable environmental conditions
Spores - resistant to death in harsh environmental conditions, dormant bacteria with minimal metabolism or respiration.

Question 12

What is meant by the antigenic power of an organism?

Answer 12

The ability of an organism to stimulate the immune system to produce antibodies or antitoxins with subsequent immunity
Measured by second attack frequency (second occurrence of same pathogen in individual)

Question 13

What is second attack rate?

Answer 13

The probability that an infection occurs within susceptible individuals within a specified time after close contact with infected individual.

Question 14

What is meant by the ease of communicability of an organism?

Answer 14

Measured by the second attack rate
Indicates the number of secondary cases likely to occur within the range of the incubation period following exposure to a primary case
Often given as a percentage of the susceptible population.
May be represented by the R-value - which is the number of people that an infected individual is expected to pass the disease on to.

Question 15

How can we break the chain of infection at the reservoir stage?

Answer 15

Ensure environmental sanitation
Disinfection and sterilisation
Water hygiene methods - filtering
Employee health in healthcare environments - using antivirals/antibiotivs when appropriate

Question 16

How can we break the chain of infection at the portal of exit stage?

Answer 16

Hand hygiene
Control of excretions and secretion
Trash and waste disposal effectively

Question 17

How can we break the chain of infection at the mean of transmission stage?

Answer 17

Isolate infected individuals
Ensure correct food handling
Airflow control (ventilation in hospitals)
Standard precautions - PPE when taking bloods etc
Sterilisation of surfaces/fomites
Hand hygine

Question 18

How can we break the chain of infection at the portal of entry stage?

Answer 18

The aseptic technique when handling clinical examinations/material e.g blood
Catheter care - insertion technique and replacement when/if needed
Wound care - wear waterproof plaster, clean around the area,
Examples - bed nets, covering skin to prevent entry through skin or mucous membranes, using insect repellents

Question 19

How can we break the chain of infection at the susceptible host?

Answer 19

Recognition of high risk patients - additional safety mechanisms e.g vaccines etc
Treatment of underlying diseases for example effective flu management to reduce risk of pneumonia, management of HIV to reduce risk of infection in AIDs.
Health education
Adequate personal hygiene
Sound nutrition
Immunixsation
Chemoprophylaxis

Question 20

How can we break the chain of infection at the infectious agent stage?

Answer 20

Rapid and accurate identification of organsisms - targeted and effective treatment
Sourcing and linking cases to identify source of infection an dhow to eradicate

Question 21

What is meant by control of a communicable disease?

Answer 21

Deliberate efforts to reduce disease or health problem burden such as mortality or morbidity to a very low level, normally until no longer a public health concern.

Question 22

What is meant by elimination of a communicable disease?

Answer 22

Termination of all modes of transmission to reduce the incidence of disease to zero
In a specific confined or local geographical space
Requires deliberate efforts and sometimes continuous intervention.

Question 23

What is meant by eradication of a communicable disease?

Answer 23

Termination of all modes of transmission of an infection
Extermination of the infectious agent worldwide

Question 24

What measured can we use to manage an infectious agent to prevent infection?

Answer 24

Sterilization
Disinfection
Antiseptics
Sanitisation
Ensure proper treatment of infected individuals

Question 25

What is sterilisation of a microbe?

Answer 25

Complete removal of all forms of living.infectious agents from a surface

Question 26

What is disinfection in terms of communicable disease?

Answer 26

A process that eliminate many or all pathogenic microorganisms, except bacterial spores on inanimate objects Note normal/healthy commensals tend to remain.

Question 27

What is antiseptic in terms of communicable disease?

Answer 27

When disinfectants, normally at lower concentrations are used on the skin to removal all or many pathogenic microorganisms. Chemical agents - stop or slow the growth of infectious agents on external surfaces such as skin.

Question 28

What is meant by sanitisation in terms of communicable disease?

Answer 28

The cleaning and disinfection of an area or an item using heat or chemicals to reduce the number of microorganisms to safe levels.

Question 29

What methods help prevent transmission of a disease?

Answer 29

Isolation of infected individuals Decontamination of formties Promote handwshing Modify ventilation and air pressure of hospital rooms containing infectious patients Control vector population (mosquito nets) Environmental - sanitation of water, food and proper sewage handling.

Question 30

What methods targeting the reservoir of infection can be used to reduce transmission?

Answer 30

Identifying cases Identifying carriers Identifying animal reservoirs

Question 31

How can identifying cases of a condition help manage it? (aka prevent transmission)

Answer 31

report to local authority and trace back to cause (the reservoir), ensure isolation or elimination of reservoir or appropriate treatment, often isolate over whole period of communicability and treatment, surveil for the longest incubation period - identify those at risk.

Question 32

How does identifying carriers of infection help manage the condition?

Answer 32

Carriers in community should be treated if needed Should be isolated from work/others until organism eliminated (esp food handlers, child worker or carer) Cost effectiveness depends on the proportion of carriers in the community to those affected and the sensitivity of their occupation.

Question 33

How is identifying any animal reservoirs of infection important in managing an infective condition?

Answer 33

Adequate animal husbandry Immunisation of anmials Treatment of infected animals or killing of infected animals To prevent spread to humans or other species/animals

Question 34

What is meant by modelling of an infectious agent?

Answer 34

Using a range of data sources - from soft sources (twitter), clinical trials, lab experiments, epidemiological studies to death reports Create a stasticial distribution of different disease aspects such as vulnerable population, effects etc Filters into a model Creates predictions on disease burden (QALYS), mortality, cost, threshold intervention coverage. Can adjust policy control variables to predict effect on disease management.

Question 35

Why is creating a model of an infectious agent useful?

Answer 35

Allos to predict outcomes and behaviours Can alter model variables particular those under policy control (such as length of isolation) to predict effect on the outcome Leads to policy control variables for example understanding cost effectiveness of vaccination

Question 36

What people are involved in managing infections in hospitals?

Answer 36

Director of infection prevention and control (DIPC) - develop and implements plans for control, monitor and adjust policies organising training as needed - authirty figure and reports to board. Infection prevention and control team - help healthcare workers and provide training on hold to limit spread on infection, advise on closure of wards and decision making during an outbreak, work with occupational health to protect health of workers and patients.

Question 37

What authorities are responsible for managing infections in the community?

Answer 37

The local authirty role is split into director of public health (focus on health in policy) and the environmental health team (sanitation, pollution, food poisoning), these are both part of the local health protection partnership The NHS are also part of this partnership, identfy community priorities and create policy according to this. NHS and LHPP are influenced by Public Health England. PHH and the Director or public health can refer to the secretary of state for Health and Social care to influence nation guidelines or access funding.

Question 38

What are the standards for outbreak recognition and declaration?

Answer 38

Intitial investigation to clarfiy nature of outbreak should begin with 24 hours Immediate risk assessment should be taken an updated as appropriate Decision around declaring the outbreak should be made and recorded at the end of the initial investigation, should involve contact with outbreak control team

Question 39

What are the standards of care for managing outbreaks for the outbreak control team?

Answer 39

OCT should be heal as sson as possible and within 3 working days of decision to meat All stakeholders should be represented at the meeting Roles and responsibilities of OCT should be recorded and agreed Lead organisation with accountability for outbreak should be agreed and recorded.

Question 40

What is the standard of management for outbreak investigation and control?

Answer 40

Control measures documented with clear timescales for implementation and responsibility Cade definition agreed and recoded Descriptive epidemiology undertaken and reviewed including key demographics, risks factors and severity of disease Review risk assessment in light of newly appearing evidence Analytical studies should influence decision making - reasons should be recorded.

Question 41

What are the standards of care for communication when managing a disease outbreak?

Answer 41

Communication stratergy agreed at first OCT meeting and reviewed throughout Absolute clarity about outbreak lead at all times with appropriate handover.

Question 42

What are the standards of care for marking the end of an outbreak in infectious disease management?

Answer 42

Final outbreak report completed within 12 weeks of formal closure of the outbreak Reports recommendations and lessons learnt reviewed within 12 months after formal closure of outbreak.

Question 43

Give a summary of the processes involved in outbreak management.

Answer 43

Incident notified Initial response and investigation Decide if outbreak should be declared Is declared decide if OCT should be established Both these decision should be reviewed as needed Actions to take include - investigations into outbreak cause/patterns, control measures such as protecting those at risk and limiting spread and communication with media and members of OCT End of outbreak declared Write a final outbreak report and constructive brief on lessons learnt and goals moving forward.

Question 44

What are some national strategies being undertaken by NHS to help infection prevention and control?

Answer 44

1. Optimise vaccine provision and reduce vaccine preventable diseases in England - focus on HPV in boys and flu vaccine uptake, work to modify NHS vaccination schedule 2. Tackle antimicrobial resistance - ensure minor and low risk surgery remains sage, reduced AMR infections Also guidance on hand hygiene, PPE, reducing occupational exposure for health care workers and guidance on managing patients.

Question 45

How would having a patient with hepatitis B (or other blood borne pathogen) influence clinical practise?

Answer 45

Need to understand routes of transmission in order to reduce risk to self and other patients (bodily fluids) Design facilities to best treat patient and reduce risk of transmission Consider patient environment Understand and minimise risk of clinical procedures such as taking blood samples Used PPE Sanitisation of environment if fluids are spilt.

Question 46

Why are hospital acquired infection problematic?

Answer 46

Many susceptible individuals in close proximity in a hospital AMR is a prominent issue Potential for rapid spread

Question 47

What are the key differences between the management of infections in hospitals v community?

Answer 47

Hospital - tends to have better control, all health care staff take responsibility Community - harder to control, blame game, only certain individuals or authority figures take responsibility.

Question 48

What is a notifiable disease?

Answer 48

A disease when registed medical professions have a statutory duty to notify the proper officer at their local council or local health protection team is suspected case of certain infections diseases. Include: disease info, doctor info and patient info. These diseases tend to have high morbidity, mortality or spread rapidly or a combination of all three.

Question 49

Give some examples of some notifiable diseases

Answer 49

Acute meningitis Botulism Cholera Food poisoning Tetanus Smallpox COVID-19

Question 50

Give some examples of some notifiable organisms

Answer 50

Clostridium botulinum Ebola virus Hepatitis A,B,C delta and E viruses Influenza virus Legionella spp Salmonella spp