4.1 Control of infectious diseases Flashcards
3 domains of public health
- Health improvement
- Health protection
- Healthcare public health
What does the Health Protection Services domain of public health provide ?
1. surveillance and control of ..
2. …. control & …. resistance
3. control of ….
4. working with … ; national & international
- new and re-emerging infections (e.g. TB) & STIs and blood borne viruses
- infection , anti-microbial
- Control of epidemics & pandemics
- other specialists
What is included in the health protection domain of public health ?
- infectious diseases
- chemicals and poisions
- radiation
- emergency response
- environmental health hazards
What is included in the healthcare public health domain of public health ?
- Clinical effectiveness
- efficiency
- service planning
- audit and evaluation
- clinical governance
- equity
What is included in the health improvement domain of public health ?
- Inequalities
- education
- housing
- employmet
- family/community
- lifestyles
- surveillance and monitoring of specific diseases and risk factors
What are the key players in health protection ?
- Specialists in communicate disease control
- director of public health/public health specialists
- infection control
- emergency planning advisors
- microbiologists
- clinicians
NATIONALLY - what is the name of the organisation which organises and delivers health protection in the UK?
UK health security agency (UKHSA)
REGIONALLY - who organises and delivers health protection in the UK?
HSA (Health Security Agency) centers
LOCALLY - who organises and delivers health protection in the UK?
Health protection teams
What kind of agency is UK Health security agency ?
executive agency of the department of health and social care, and a distinct organisation with operational autonomy
What does UK Health Security Agency provide ?
government, local government, the NHS, and the public with evidence-based professional, scientific expertise and support
What does infectious disease epidemiology seek to understand ?
pattern of infectious diseases within populattions and work to control those diseases
Name 3 points that infectious disease epidemiology use ?
- measures of disease frequency, including incidence and prevalence
- a wide range of research methods, including cohort studies, case - control studies, observational studies, etc.
- statistical methods to analyse data and test hypotheses
What is an infectious agent ?
a pathogen (viral, bacterial, protozoal, fungal) that causes disease
Globally infectious diseases causes over … % of all deaths ?
20%
Special features of infectious disease epidemiology :
- even if not recognised as a case what may it also be …?
- what can occur ?
- what can be critical ?
- a case of disease may also be a risk factor
- immunity can occur
- speed of intervention can be critical
Define infection
the entry and development or multiplication of an infectious agent in the body - the result may or may not be apparent
infectious disease = communicable disease : an illness due to …
a specific infectious agent or its toxic products that arises through transmission of the agent / products to a susceptible host
contagious transmitted by ?
transmitted by contact
disease surveillance = ongoing ….1…. of data to guide public health action. It is the ..2… by which we can obtain “information for action “
- collection, compilation and analysis
- process
What are the 6 steps involved in disease surveillance ?
- collect
- collate
- analyse
- interpret
- disseminate, act.
Information for disease surveillance is the product of surveillance.
However, in order for the information to be most effective it need to be what ?
- timely
- accurate
- 2 methods of surveillance
- 2 types of surveillance
- Passive & active
- routine & enhanced
Sources of information of infectious disease ?
- Primary care reporting systems
- hospital information systems
- laboraties
- population surveys
- clinicians
- environmental health officers
- care/nursing homes
- death certification & registration
- the general public
Passive surveillance:
A system by which a ..1.. (e.g. the local authority or the UK Health Security Agency UKHSA) receives reports of ..2… diseases or other illnesses submitted from ..3.., or other sources.
Cheap, but with reduced ..4.. and completeness
- designated body
- infectious
- hospitals, clinics, public health units
- quality
Active surveillance:
A system whereby staff members of a designated body (e.g. UK Health Security Agency UKHSA) ..1… health care providers or the population to ..2.. about health conditions.
Relatively more ..3.., but it provides more …4.. and timely information.
- regularly contact
- seek information
- expensive
- accurate
Difference between the 2 methods of surveillance: passive & active ?
Passive
* designated body receives reports of infectious disease / illnesses from sources
* cheap
* reduced quality & completeness
Active
* designated body regularly contact health care providers / population to seek info about health conditions
* relatively more expensive
* provides more accurate & timely information
Routine surveillance involves collection of …?
a basic minimum data set, often from one source of data
Examples of sources of data involved in the collection of a basic minimum data set for routine surveillance ?
statutory notification of infectious diseases (e.g. NOIDs, laboratory surveillance)
statutory notification of infectious diseases (e.g. NOIDs, laboratory surveillance) are examples of routine surveillance.
1. What does this refer to ?
2. essential why ?
- diseases that health professionals and laboratories are required by law to report to public health authorities when diagnosed
statutory notification of infectious diseases (e.g. NOIDs, laboratory surveillance) are examples of routine surveillance.
1. essential why ?
- disease surveillance, outbreak control, and public health interventions
Enhanced surveillance:
1. involves colleciton of what ?
2. may combine what data?
3. may include ?
- more detailed data set from informants
- epidemiological and microbiological data
- multiple sources of data
Examples of collection of a more detailed data set from informants for enhanced surveillance ? [change Q!] (is it a necessary question ?)
meningococcal disease, tuberculosis, listeriosis, enteric fevers, antimicrobial resistance and travel associated legionella infection
Where do we mainly get information from ?
- primary care reporting systems e.g. GPs, pharmacists, NHS direct, NPFS (National Primary Care Surveillance )
- hostpital information systems
- laboratories
List some routine notifiable UK diseases
- acute encephalitis
- scarlet fever
- leprosy
- mumps
- rubella
- typhus
Disease that’s urgent if suspected bacterial infection, otherwise routine ?
acute meningitis
Diseases that are routine; urgent if UK acquired ?
- Brucellosis
- Malaria
- yellow fever
Disease that routine; urgent if as part of a cluster or outbreak
food poisoning
Disease that’s routine; urgent if associated with injecting drug use
tetanus
Disease that’s routine; urgent if healthcare worker or suspected cluster or multi drug resistant
tuberculosis
Disease that’s urgent if diagnosed in acute phase; routine if later diagnosis
whooping cough
What criterial would be used to decide whether a disease should be notifiable ?
Think effectiveness
- prevalence and severity of disease
- possibility of source and contact tracing
- derived risks for vaccination policy
- international consequences
What criterial would be used to decide whether a disease should be notifiable ?
Think feasibility
- workload
- possibility of diagnosis
What criterial would be used to decide whether a disease should be notifiable ?
Think necessity
privacy
How can a consultant in communicable disease control (CCDC) respond to a disease notification?
- tracing contact of the index case infected person
- interviewing affected people to identify the source of infection e.g. food poisoning outbreak
- confirming the diagnosis by further testing the infected person
Tracing contacts of the index case infected person to do what ?
- identify source of the infection
- prevent further dissemination e.g. tuberculosis
What happens with a disease notification ? flowchart idea to end up at UK HSA: centre for infections ?
- GP/hospital clinician -> clinical laboratory OR straight to health protection team: propter officer
- If GP/hospital clinican -> clinical laboratory THEN -> health protection team: proper officer
- THEN -> UK HSA: centre for infections
4 limitations of surveillance ?
- under reporting
- lack of representativeness of reported cases
- trends are difficult to interpret
- lack of denominators
Why is under-reporting a limitation of surveillance?
Only a fraction of all notifiable diseases are ever reported, as most surveillance is based on passive reporting by clinical and other healthcare staff
Why is lack of represnetativeness of reported cases a limitation of surveillance ?
* clinicians are more likely to report more …1… illnesses or report diseases that have ..2..
- serious
- generated media interest
Why is trends are difficult to interpret a limitation of surveillance ?
data are sensitive to changes in testing or reporting by laboratories
Why is ‘lack of denominators’ a limitation of surveillance ?
1. data are based on …. rather than ….
2. negatives are not usually ….., neither the number of ….. tested no the population at risk is known with certainty
- place of treatment , place of residence
- reported, specimens
Case terminology
Index case
First case of disease identified
Case terminology
Primary case
The case that brings the infection into the population
Case terminology
Secondary case
The case that was infected by the primary case
case terminology: tertiary case
The case that was infected by the secondary case
Chain of transmission ?
1) -> 6)
1) Infectious Agent
2) Reservoir
3) Portal of Exit
4) Mode of Transmission
5) Portal of Entry
6) Susceptible Host
Transmission routes
Give some examples of direct transmission routes
- Mucous to mucous membrane
- Across placenta
- Transplants, blood
- Skin to skin
- Sneezes/cough
Transmission routes
Give some examples of indirect transmission routes
- waterborne
- airborne
- foodborne
- vectorborne
- objects/fomites
- What is a reservoir related to pathogens?
- What can be reservoirs for microorganisms ?
- a host which allows the pathogen to live , possibly grow and multiply
- humans, animals, the environment
Vector = a host that…
carries a pthogen without injury to itself and spreads the pathogen to susceptible organism
What type of carrier of pathogens is a vector ?
asymptomatic
Definition of disease occurences in populations
Sporadic definition
occasional cases occuring at irregular intervals
Definition of disease occurences in populations
endemic definition ?
continuous occurrence at an expected frequency over a certain period of time and in a certain geographical location
Definition of disease occurences in populations
epidemic or outbreak definition ?
occurence in a community or region of cases of an illness with a frequency clearly in excess of normal expectancy
Definition of disease occurences in populations
pandemic definition ?
epidemic involves several countries or continents, affecting a large population
Difference between endemic, epidemic and pandemic
Endemic = transmission occurs, but number of cases stays constant.
Epidemic = number of cases is increasing.
Pandemic = when epidemics occur in SEVERAL continents - global epidemic.
COVID-19, previously also known as what ?
WN CoV, 2019 nCoV
COVID-19 disease is caused by the virus…
SARS-CoV-2 (Severe Acute Respiratory Syndrome - Coronavirus 2)
Coronaviruses are common respiratory viruses that can cause what type of symptoms…
- cough
- fever
- pneumonia in some cases e.g. MERS
what does the “corona” in coronaviruses mean ?
crown
Transmission of COVID-19
- usually spreads from close person-to-person contact through respiratory droplets (coughin/sneezing)
- airbone transmission (tiny droplets remain in air even after person with virus leaves the area)
COVID-19 can only be diagnosed with what test ?
a laboratory test
Most cases of COVID-19 seen to have a mild illness but some develop a …1.. requiring ….2.. that can be ..3…
- more severe illness
- high dependency/intensive care
- fatal
Those with COVID-19 who have ….. are more at risk of severe infection ?
compromised immune systems or other co morbidities
What was COVID-19 considered to be ?
a high consequence infectious disease (HCID)
What were the 4 phases of UK’s response to COVID-19 ? Include what each phase contained !
- contain = early case detection, intense contact tracing to prevent disease from embedding in the community
- delay = slow the spread, delay the peak and push it away from winter
- research = diagnostics, drugs and vaccines
- mitigate = focus on those crticially unwell and maintain essential services
Name 3 COVID-19 vaccines suggested by public health england
- Pfizer/BioNTech
- AstraZeneca
- Moderna
Preventing COVID-19
- Practise social distancing
- Wear face mask
- Wash hands carefully/frequently
- Open windows for fresh air
- Get tested (LFD if asymptomatic; PCR if symptomatic)
What is one of the key tools in controlling the COVID-19 pandemic ?
vaccination
What are the key priorities of the Health Protection domain of Public Health?
1) Prepare for and control outbreaks and pandemics
2) Surveillance & control of new/re-emerging infection e.g., TB
3) Protect population from hazards (e.g., environmental)
4) Vaccination, screening programs
5) Infection control and anti-microbial resistance
