PH- communicable Disease Flashcards
define surveillance
Reasons for surveillance
Ongoing, systematic collection, collation & analysis. + interpretation of data + desemination of information in order for action to be taken —> information for action
Reasons: -monitor trends - provide early warning of outbreaks -control measures effectiveness
Surveillance systems
- notifications of infectious diseases -laboratory notifications (+test results —> PHE) -primary care surveillance systems E.G. RCGP for influenza -secondary care surveillance systems -disease specific systems e.g. HIV
Agent/host/Environment determines spread of infectious diseases
Agent Environment: temperature, sanitation, crowding Host factors: age, gender, ethnicity, immunity
What do PHE do?
Responsible for taking notifications and management of outbreaks
What do NHS England do?
Lead & coordinate NHS response to significant outbreaks
What do CCGs do?
Support NHS England in large outbreaks. Commission community and trust support in smaller outbreaks
What do primary care and community trusts do?
Outbreak investigation & management e.g. collecting samples/organising treatment/prophylaxis
What do hospital trusts do?
Provide microbiological advice. Director of infection prevention & control leads outbreak management
What do local authorities do?
Environmental health officer investigated source of outbreak. Director of PH ensures protection of population & supports response
Notifiable infections include
TB, food poisoning, mumps, cholera, meningitis, encephalitis, measles, scarlet fever, whooping cough, yellow fever, diphtheria
Transmission chain = Infectious agent Reservoir Portal of exit Mode of transmission Portal of entry Susceptible host How do we break the chain of transmission?
-control the source -interrupt transmission -protect susceptible population e.g. immunisation/ chemoprophylaxis
Transmission modes-direct examples
Touching - scabies Sex - hepB, STIs Droplet - flu, mumps, meningococcal Vertical - e.g. birth/placental - HIV, CMV, toxoplasmosis Faeco -oral - e.g. on objects/food - hepA, salmonella, campylobacter
Transmission modes - indirect Examples
Vehicle borne - living carrier - flu Vector borne- malaria Airborne - TB
Define endemic
Persistent low/mod level of disease
Define hyper-endemic
Higher persistent level of disease
Epidemic Curves:
POINT SOURCE
Persons are exposed to the same common source over a brief period of time, such as through a single meal or event attended by all cases; number of cases rise rapidly to a peak and falls off gradually; majority of cases occur within one incubation period.
EPIDEMIC CURVES
Continuous Source
Continuous common source – Exposure is not confined to one point in time (prolonged over a period of days, weeks or longer); as such, cases are spread over a greater period of time depending on how long the exposure persists; lasts more than one incubation period
E.g GI organisms
EPIDEMIC CURVES
Propagated Spread
Propagated source – does not have a common source but instead caused by spread of pathogen from one susceptible person to another; transmission may occur directly (person-to-person) or via an intermediate host; tends to have a series of irregular peaks; multiple peaks separated by approx. one incubation period; e.g., person-to-person spread of shigellosis
e.g. NOROVIRUS
Timeline of infectious diseases
E.g. How does incubation period relate to symptoms?
