EPIDEMIOLOGY
I. Teminology
- Epidemiology
- Health
- Disease
- Sporadic disease
- Endemic
- Epidemic
- Outbreak
- Cluster
- Index case
- Pandemic
- Zoonosis
II. Measuring Frequencies
- Rates of diseases and deaths generally expressed as ratio
___________# experiencing event______________
# individuals who could have experienced the event
- Expressed as a multiple of 10
- e.g. incidence of congenital syphilis in 2003 was 413 cases.
10.3/100,000 live births
- Morbidity rate — # of individuals who became ill during a specified time period
- E.g. Incidence of tuberculosis in 2003
| # cases |
Rate |
Population |
| 14,874 |
5.1/100,000 |
Overall |
| 3,425 |
29.3/100,000 |
Asian Americans |
| 4,145 |
11.6/100,000 |
African Americans |
| 4,115 |
10.6/100,000 |
Hispanics |
| 2,790 |
1.4/100,000 |
Whites |
- Mortality rate — relationship between # of deaths and total # of people exposed to the disease
III. Recognition of an Epidemic
- Public health surveillance
- Phone calls from health providers
- Common-source epidemic – single contamination source
- Propagated-source – single infected person spreads disease to others
- Epidemic curve
- Important to establish a case definition
- Probable or possible
- Confirmed
IV. Nosocomial Infections
A. Introduction/Significance
- Hospital acquired
- 5-10% of all hospitalized patients
- Substantial mortality
- Financial cost
B. High Risk Patients
C. Controlling Nosocomial Infections
- Frequent surveillance
- Focused infection control
- Thorough cleaning
- Patient isolation
- Infectious disease committee
- Hand washing
Last updated June 20, 2007.