Infectious Disease Flashcards
(31 cards)
What is a communicable disease? Give 4 examples.
A disease which can be transmitted directly or indirectly to man or animal. It is caused as a result of infection (pathogen or toxin entry and multiplication). Direct transmission between man refers to a contagious disease (STD, TB, scabies, mono, influenza). Non-contagious diseases are those which require a vector to be transmitted to man (e.g. malaria, Lyme disease). A vector will transmit an infectious agent between the reservoir and the host.
What is the UK Notifiable Disease Register? Name 4 diseases on this. What kind of surveillance is this?
Medical practitioners in the UK are required to notify the health authority of cases of notifiable infectious disease. This allows early detection out outbreak and monitoring of prevention systems. Local trends are published weekly.
Meningitis, measles, mumps, rubella.
This is a form of active surveillance.
What is Infectious Disease Epidemiology?
A form of epidemiology associated with the spread of infectious disease, new cases of infectious disease and establishing links between infections and chronic disease.
What is an endemic? Give 2 examples.
The normal/stable levels of an infectious disease within a country. E.g. chicken pox in the UK, malaria in sub saharan Africa.
What is an epidemic? Give 2 examples.
The rapid spread of an infectious disease in a short time. E.g. the SARS epidemic (Severe acute respiratory syndrome) affected over 800 thousand in 2003. The most recent epidemic is occurring currently in Mozambique and is a result of Cholera.
Why do epidemics occur?
Increased virulence of the pathogen
Reduced immunity of the host
Introduction of the pathogen into a novel environment
What is a pandemic? What pathogen is the most common cause of pandemics?
Worldwide spread of an epidemic. Influenza pandemics are the most common e.g. Spanish Influenza, Asian Influenza and Hong Kong Influenza. H5N1 bird flu pandemic 1997.
Why do pandemics occur?
Mutations in the virus lead to new strains that the population do not have immunity against. E.g. Influenza H and N surface antigen mutations cause pandemic influenza.
What is the WHO pandemic scale?
An influenza pandemic warning system. Ranges from phase 1 (low risk) to phase 6(full pandemic)
What is an exotic disease? Give 2 examples.
A disease which appears in an area it is not endemic to. For example the West nile virus appeared in NYC. Bird flu in humans
What is a sporadic disease?
A disease scattered around, appears infrequently, can lead to epidemics in favourable conditions.
What are the two main forms of CJD? What are the symptoms.
Sporadic and Variant (acquired). CJD is a neurodegenerative condition passed via blood.
How does variant CJD occur?
Variant CJD is as a result of BSE outbreak in cows (mad cow disease). Cows infected as a result of eating sheep infection with Scrapie (CNS disease).
When was the first outbreak of BSE?
1986
How many cattle were affected in the UK up to 2001?
180,000
When was the first variant CJD case reported?
1996
Between what period did the EU ban British beef
1996-1999
When was the most recent BSE case?
2018 in Aberdeen
What are the main differences between variant and genetic CJD?
Earlier onset, longer duration, makes up the majority of UK cases, affects a wider range of tissues.
What is surveillance?
The ongoing collection, analysis and interpretation of data to reduce mortality and morbidity.
What are the four types of surveillance?
Passive, Active, Sentinel, Rumour
What is Passive surveillance? What are the adv/disadv?
Use of routine data sources (registries (NCRAS, EUROCAT, FLUNET), mortality statistics, questionnaires, notifiable disease register, healthcare data).
Adv - cheap, easy to obtain, can cross link databases to obtain more info
DisAdv - cannot be sure of data completeness and accuracy. Different registers may contain different details.
What is active surveillance? What are the adv/disadv?
Active collection of data on infectious disease. Using methods of serosurveillane (blood samples), going to place of epidemic to determine those affected, telephone interviews, contact tracing.
Adv - Accurate, up to date
DisAdv - expensive, takes time to obtain this information
What is sentinel surveillance? What are the adv/disadv?
Using a sample representative population. Involves the use of selected reporting centres - e.g. selected large hospitals around the country. Need to choose a centre with relatively large population base, trained staff and good diagnostic equipment.
Adv - good representative of a population
DisAdv - not good for rare diseases or diseases outside of catchment of the selected centre.
