Healthy Pop Block 2 Health and Disease Surveillance

surveillance definition

collection, analysis and interpretation of data and dissemination of information to take action

What does surveillance target?

agents/diseases for which a rapid, direct, predetermined action is warranted

What is important in surveillance in order to obtain, process, and communicate information rapidly?

to maximize early detection (sensitivity) & minimize false positives (specificity)

What does surveillance measure?

magnitude, changes, and trends in populations to intervene

monitoring definition

surveillance without an intervention threshold

screening definition

testing apparently healthy individuals to confirm negative status and identify previously unknown infected/diseased individuals

What is goal of surveillance?

control and/or prevent diseases

Why is surveillance during potential outbreak important?

help with disease prevention and control efforts

Why is surveillance during non-outbreak important?

provide information about baseline levels of disease (baseline serves as reference in future outbreaks)

Objectvie of early detection

identify disease rapidly before significant spread to facilitate disease control

Surveillance for early detection should be

1. continuous

2. representative of full population

3. sensitive to detect rare cases

objective of demonstrate freedom

1. provide proof that disease is not present in population

surveillance to demonstrate freedom…

1. does not need to be continuous, can be ad hoc or intermittent

2. may use risk-based surveillance to increase efficiency

3. may be designed to detect higher prevalence than early detection

objective of case finding

identify infected animals, flocks, or herds during control program

case finding surveillance should

1. use comprehensive coverage of population (risk-based approaches can focus on high risk parts of population)

2. be ongoing (or periodic if infection rate of spread is low)

3. have good individual herd or animal sensitivity

objective of measuring disease

to detect changes in level of disease in population

surveillance to measure disease…

1. does not need to be continuous but can be ad hoc or periodic

2. should be based on representative sampling to avoid bias

3. should use big enough sample size to give adequate precision

uses for surveillance information

1. monitoring disease trends

2. describing natural history of diseases

3. identifying epidemics or new syndromes

4. reulatory and trade

5. monitoring changes in infectious agents

6. identifying areas for research

7. evaluating hypotheses

8. planning health policy

9. evaluating interventions

surveillance agencies for human health

1. state/regional public health

2. CDC

3. FDA

surveillance agencies for animal health

1. state departments of agriculture

2. USDA APHIS

3. NAHLN

passive surveillance

surveillance utilizing samples or observations collected primarily for another purpose; majority of government surveillance systems are passive

active surveillance

surveillance utilizing samples or observations collected specifically for use by surveillance program

what does passive surveillance rely on?

health care providers or laboratories to report cases of disease

Advantage of passive surveillance

efficiencey - simple and requires relatively few resources

disadvantage of passive surveillance

possibility of incomplete data due to underreporting

Why is active surveillance needed?

needed for rare or hard to detect diseases; involves ongoing search for cases

advantages of active surveillance

high levels of completeness

Disavantages of active surveillance

very expensive to maintain

antibiogram definition

periodic summary of antimicrobial susceptibility results for selected bacterial pathogens recovered from a defined patient population; provide info about local antimicrobial resistance

antibiogram components

1. antimicrobials tested

2. organisms tested

3. number of isolates for each organism

4. percentage of isolates susceptible for each drug/pathogen combination

5. specimen site notation where appropriate/needed

how are antibiograms used

inform empiric therapy specific to patient population

disadvantage of antibiogram

data can be difficult to obtain and analyze