Endemic –

Epidemic –

Pandemic –

Epidemiology Part 1 Chapters 4 - 6

Objectives Epidemiology • The ______discipline of public After completing this lecture, you will be able to: health • A major part of public health’s • Define and describe epidemiology ______function • Investigates ______of diseases • Identifies ______in disease • Explain why John Snow is call the Father of occurrence Modern Epidemiology • ______effectiveness of medical and public health interventions

Definition of Epidemiology Human Population

Epidemiology is the study of the ______in human populations

Epidemiology -- The 3 D’s o Distribution Biomedical sciences: o Determinants Epidemiology: o Disease frequency Performs experiments on Observes humans laboratory animals

High death rates based about parts of the city with John Snow and Cholera water supplied by 2 companies [1) Lambeth 2) Southwark and Vauxhall] from the Thames River at a • Cholera epidemics in London, mid 1850s point of heavy sewage pollution. Lambeth changed their water supply location and saw decreased deaths.

Snow made the hypothesis: Cholera was spread by ______water.

Between August 1853 and January 1854 John Snow John Snow Data went to each house where someone died of cholera and determined which water company they got their water from.

When you compare the three groups… John Snow Data

Rate = number of deaths/population at risk

Cholera death rate = # of people who died from cholera/# of houses get water from that water company

Sourthwark & Vauxhall - 315 deaths per 10,000 houses •1,263/40,046 = .0315 = 315 per 10,000

Lambeth - 37 deaths per 10,000 houses •98/26,107 = .0037 = 37 per 10,000

Rest of London - 59 deaths per 10,000 houses •1,422/256,423 = .0059 = 59 per 10,000

Natural experiment - John Snow and Cholera

• Conclusion • Natural Experiment