Week 1: Biology and Public Health

Question 1

What is public health?

Answer 1

Public health refers to all organized measures (whether public or private) to prevent disease, promote health, and prolong life among the population as a whole

Question 2

What makes public health different from the other health professions?

Answer 2

Public health focuses on the health of entire populations while they are still healthy rather than on individual patients after they become sick

Question 3

Name 7 different disciplines involved in public health.

Answer 3

Epidemiology

Biostatistics

Public health laboratory practice

Nutrition

International and global health

Public health policy

Health education

Environmental health

Maternal and child health

Public health practice

Emergency medical sciences

Question 4

What are the 3 main public health functions?

Answer 4

Assessment and monitoring of the health of communities and populations at risk to identify health problems and practice

Formulation of public policies designed to solve identified local and national health problems and priorities

Assure that all populations have access to appropriate and cost-effective care, including health promotion and disease prevention services

Question 5

What are 3 impacts of public health?

Answer 5

Increase in life expectancy

Worldwide reduction in infant and child mortality

Elimination or reduction of many communicable diseases

Question 6

What is the breakdown of the roles public health and medical advances have played in increasing lifespans of populations?

Answer 6

Over 25 years of public health and less than 4 of medical advances

Question 7

What are 6 reasons that demonstrate the need for biology in public health?

Answer 7

Basic knowledge in biology helps with understanding infectious disease transmission, vector and reservoir animal population dynamics

Helps to control zoonotic disease that require knowledge of infectious agents (life cycle and transmission) along with their prevention methods

Use of chemical and biological control agents

Helps to independently conduct scientific studies required to evaluate animal-related disease and control problems

Helps to distinguish among the characteristics of viral, bacterial, parasitic, and other types of disease pathogens

Helps to identify the known associations between genetic factors and common diseases

Question 8

What is the graphic for the dynamics of disease called?

Answer 8

The epidemiological triad

Question 9

What are the 3 corners of the epidemiological triad?

Answer 9

1. Agent or microbe that causes the “what”
2. Host or organism harboring the disease (“the who”)
3. Environment or those external factors that cause or allow disease transmission (“the where”)

Question 10

Give 1 detail about the agent or microbe that causes the “what.”

Answer 10

Disease-causing microbes are bacteria, virus, fungi, and protozoa (a type of parasite)

Question 11

Give 3 details about the host or organism that harbors the disease (“the who”).

Answer 11

Can be organism that gets sick or any animal carrier (like insects or worms) that can/cannot get sick

Also includes symptoms of disease

Different people may have different reactions to the same agent

Question 12

Give 2 details about the environment or external factors that cause or allow disease transmission (“the where”).

Answer 12

Favorable surroundings and conditions external to the host that cause or allow the disease to be transmitted

Other factors include the season and time

Question 13

What 3 things can “time” refer to when talking about the epidemiological triad?

Answer 13

Incubation period: time between host infection and disease symptoms occur

Duration of the illness

Period from an infection to the threshold of an epidemic for a population

Question 14

How many factors are necessary to interact after the outcome (deviation from normal homeostasis)?

Answer 14

At least 2

Question 15

What are 3 examples of environmental diseases?

Answer 15

Toxins (lead poisoning)

Cancers

Environmental shortages (famine)

Question 16

What system is used when talking about directly transmissible infectious disease?

Answer 16

Two population system

Question 17

Give 3 examples of two population systems.

Answer 17

Many viral (influenza, measles), bacterial (tetanus), and fungal (aspergillus) infections

Question 18

What are zoonotic diseases? Give 2 examples.

Answer 18

Zoonotic diseases: pathogen primarily resides in second species and is transmitted to humans without an intermediary species

Examples: rabies and schistosomiasis

Question 19

Summarize the epidemiological triad.

Answer 19

The mission of the epidemiologist is to break one of the legs of the triangle, which disrupts the connection between environment, host, and agent, stopping the continuation of an outbreak

Goals of public health: control and prevention of disease

By breaking one of the legs of the triangle, public health intervention can partially realize these goals and stop epidemics

Question 20

What are the 4 broad categories of the determinants of health?

Answer 20

Social factors

Health services

Individual behavior

Biology and genetics

Question 21

List 7 major determinants of health.

Answer 21

Where you live (middle or low income countries)

Genetics

Income (USA)

Nutrition (middle or low income countries)

Education (USA)

Relationships with friends and family

Gender

Culture

Social status and social exclusion

Access to and use of health services (middle income or low income countries)

Personal health behaviors

Question 22

Summarize the scientific method.

Answer 22

Make observations (ask questions, gather information)

Formulate hypotheses (propose explanation for observations)

Prediction (based on hypothesis, project outcome)

Experiment (test prediction, modify hypothesis)

Emphasis on steps sometimes differs in “modern” practice

Question 23

What disease did John Snow help prevent?

Answer 23

Cholera

Question 24

Summarize the story of John Snow and the first cholera outbreak.

Answer 24

Infectious diseases were leading cause of death in mid-19th century

Up to half of all children died before the age of 5, mostly due to infectious disease

Snow’s first study was conducted in 1848 when an epidemic of cholera hit the Golden Square area of London

Even before bacteria were discovered as a cause of disease, Snow was able to stop devastating outbreaks by observing and recording information about the distribution of the disease

Observation and hypothesis:
Cholera outbreaks (recently seen in Haiti) were previously common and a major cause of death

Mid-1800s: existing data on cholera deaths were consistent with a theory of a “miasmatic” cloud

Cloud was said to hover close to the ground

Hypothesized that water polluted water was the cause of cholera, and when one water company moved its intake upstream on the Thames in London, he had a basis for testing the hypothesis

Snow developed a spot map that showed the distribution of cases in relation to water pumps

After investigating, he found that many cholera cases were clustered around the Broad Street Pump and confirmed with families of cholera victims that they used the pump

Showed that by studying the case distribution, a source of infection could be found that explained the pattern

He stopped the epidemic by having the pump handle removed

Question 25

Summarize the story of John Snow and the second cholera outbreak.

Answer 25

Snow did additional pioneering work during another cholera outbreak In 1854

Outbreak affected several areas of London that depended on water hauled in by wagon

Two companies did the hauling and Snow compared the number of cholera deaths in the various districts

Raw numbers could not tell him much because some districts couldn’t be compared due to different populations

He collected population figures from the most recent census and calculated cholera death rates per 1,000 people

Death rate was 22x higher in the districts served by only one company compared to districts served only by the other one

Further investigation showed that both companies were drawing their water from the Thames

Snow showed conclusively that water could serve as a vehicle for transmitting infection; also showed humans could intervene, in this case by changing the location of the company’s water intake