12. Endemic & Epidemic Disease

Outbreak Investigation Goals

-identify the source of illness -guide public health intervention

Ways to recognize an outbreak

-routine surveillance activities -repots from clinicians and labs -report from affected indviduals

4 components of Case Definition

1. clinical information about disease (sigh and symptoms) 2. characteristics of affected 3. information about the location or place 4. specification f time which illness occured

Steps of Outbreak Investigation

1. establish the existence of an outbreak 2.preparing for fieldwork 3.verifying the diagnosis 4. defining & identifying cases 5. using descriptive epi 6. developing hypothesis 7. evaluating hypothesis 8. refining hypothesis 9. implementing control & prevention 10. communicating findings

Case Definition

a list of specific criteria used to decide whether or not a person has the disease

Cluster

an aggregation of cases grouped in a place in time that are suspected to be greater than the number expected

Pandemic

an epidemic that has spread over several countries or continents, affecting a large number of people

Epidemic

an increase, often sudden, in the number of cases of disease above what is normally expected in that population -occurs when an agent and susceptible hosts are present in adequate numbers

Endemic

constant presence and/or usual prevalence of disease in a population and geographic areas -expected level of disease

Point-Source Outbreak

outbreak where individuals are exposed more or less simultaneously -> very rapid increase in cases in a short time -food poisoning

Intermittent or Continuous Outbreak

outbreak where individuals are exposed over a brief or long period -> irregular peaks reflecting timing of exposure -contaminated water

Common-Source Outbreak

outbreak which a group of persons are all exposed to an infectious agent from the same source

Outbreak

same as epidemic, but often used for a more limited geographic area

Propagated Outbreaks

spread from person to person -can last longer than common source outbreaks -have multiple waves -flu