GEN-101: Public Health

Pete Walton, M.D.Associate Dean for Academic Affairs

School of Public Health and Information Sciences

What is Public Health?

“Public health is the science and art of promoting health, preventing disease, and prolonging life in the population through the organized efforts of society.”

-- World Health Organization (WHO)

science and artpromoting health preventing diseaseprolonging life in the populationorganized efforts of society

Functions of Public Health

Population Health

Health Care Traditional Public Health Social Policy

Population Health

HospitalsClinicsProvidersInsurersResearchersEtc.

ACAMedicaidTaxationSmokingGunsEtc.

Career Areas• Medicine• Dentistry• Health management• Epidemiology• Environmental health• Health information• Wellness• Health policy

• Health inspection• Social policy• Research• Health instruction• Program planning• Program evaluation• Health assessment• Community health

Public Health CompetenciesDiscipline-Specific Cross-Cutting

biostatistics communications and informatics

environmental health sciences diversity and culture

epidemiology leadership

health policy and management public health biology

social and behavioral sciences professionalism

program planning

systems thinking (critical thinking)

How Do We “Measure” Disease

• Morbidity – being sick– Prevalence – proportion of people who are sick at

a given point in time– Incidence – proportion of people who get sick

during a given period of time• Mortality – deceased

– Mortality rate – proportion of people who die during a given period of time

How Do People Get Infections?• Agents

– Bacteria– Viruses– Protozoa (one-celled animals)– Fungi (plant-like)– Helminths (worm-like parasites)– Infectious proteins (e.g., mad-cow disease)

• Routes– Inhaled – droplets, cysts & spores– Contact – direct, indirect– Ingested – food, water & other liquids & solids– Through skin – bites, needles, wounds & cuts

Key Assumption of Evidence-Based Population Health

“The underlying theory of population health is that the distribution of health and disease in the population is not random and that we can identify the reasons for the non-randomness.”

The Origin of Evidenced-based Public Health:Cholera in 19th-Century London

1831-1832: first modern outbreak in Britain 23,000 deaths helped to launch the sanitary reform movement, which was

based on miasma theory of disease (“bad smells”)

1848-1849: 250,000 cases and 53,000 deaths prompted Snow (and others) to investigate causes based on

contagion theory of disease (“person-to-person spread”)

Snow’s “Ghost Map”

What’s your interpretation of the evidence on this map?

Black squares are cholera deaths

The green circles are public water pumps.

Other Pumps (Lambeth and others)

Broad StreetPump (Southwark

& Vauxahall)

Snow’s “Ghost Map”

John Snow’s Numerical Analysis

Water Supplier # of Houses # of Deaths Deaths/10,000 Houses

Southwark & Vauxhall 40,046 1,263 315

Lambeth 26,107 98 38

Other 256,423 1,422 56

315

What Really Happened• Removal of the Broad Street pump handle by Snow, thereby

stopping the epidemic, is legend and NOT based on historical evidence.– He persuaded the public authorities to remove it (grudgingly),

and it was removed after the epidemic had already peaked.• It took Snow years to convince the authorities that water

was the problem, not smelly air, and to force the water company to change where it drew water from the Thames,– Which was right downstream from the outlet from one of the

sewers built to eliminate miasma!• Snow died in 1858; the cholera bacterium was not

discovered until 1884 and proven by Koch to cause cholera.

Questions