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Chap 4: Epidemiology: Prevention and
Control of Disease and Health Conditions
Instructor’s name
Semester, 200_
Chap 4: Prevention and Control
Chapter Objectives
• Explain the difference between communicable
and noncommunicable diseases and between
acute and chronic diseases.
• Describe and explain communicable and
multicausation disease models.
• Explain why noncommunicable diseases are a
community health concern and provide some
examples of communicable and provide some
examples of important noncommunicable
diseases
Chap 4: Prevention and Control
Chapter Objectives
• Explain how communicable diseases are
transmitted in a community using the
“chain of infection” model and use a
specific communicable disease to
illustrate your explanation.
• Explain the difference between primary,
secondary, and tertiary prevention of
disease.
Chap 4: Prevention and Control
Chapter Objectives
• List and explain the various criteria that
communities might use in order to
prioritize their health problems in
preparation for the allocation of
prevention and control resources
• List and discuss the measures for
preventing and controlling the spread of
communicable diseases in a community.
Chap 4: Prevention and Control
Chapter Objectives
• List and discuss approaches to noncommunicable disease control in a
community.
• Define and explain the purpose and
importance of health screenings.
• Outline a chronic, noncommunicable
disease control program that includes
primary, secondary, and tertiary disease
prevention components.
Chap 4: Prevention and Control
Classification of Diseases &
Health Problems
• 4 Classification Schemes
• Organ or Organ System
– i.e., heart disease, kidney disease,
respiratory infection
• Causative Agent
– Biological Agents
– Chemical Agents
– Physical Agents
Chap 4: Prevention and Control
Causative Agents for Diseases & Injuries
Biological
Agents
Viruses
Rickettsiae
Bacteria
Fungi
Protozoa
Metazoa
Chemical
Agents
Pesticides
Food additives
Pharmacologics
Industrial chemicals
Air pollutants
Cigarette smoke
Physical
Agents
Heat
Light
Radiation
Noise
Vibration
Speeding
objects
Chap 4: Prevention and Control
Classification of Diseases &
Health Problems
• Organ or Organ System
– i.e., heart disease, kidney disease, respiratory
infection
• Causative Agent
– Biological Agents
– Chemical Agents
– Physical Agents
• Communicable vs Non communicable
• Acute vs Chronic
– Peak symptoms within 3 months (acute) or longer
than 3 months (chronic)
Chap 4: Prevention and Control
Types of Diseases
Examples
Acute Diseases
Communicable
Common cold, pneumonia,
mumps, measles, pertussis,
typhoid fever, cholera
Noncommunicable
Appendicitis, poisoning, trauma
Chronic Diseases
Communicable
Noncommunicable
Tuberculosis, AIDS, Lyme disease,
syphilis, rheumatic fever
Diabetes, coronary heart disease,
osteoarthritis, cirrhosis of the liver
Chap 4: Prevention and Control
Communicable Disease Model
Model
Chap 4: Prevention and Control
Communicable Disease Model
Agent - the element that
must be present in order
for the diseases to occur.
Chap 4: Prevention and Control
Communicable Disease Model
Host - any susceptible
organism invaded
by an infectious agent
Agent
Chap 4: Prevention and Control
Communicable Disease Model
Host
Agent
Environment - all
other factors that inhibit
or promote disease
transmission.
Chap 4: Prevention and Control
Chain of Infection
A model to conceptualize the transmission of a
communicable disease from its source to a susceptible hose
Chap 4: Prevention and Control
Chain of Infection
Pathogen
- is the disease causing agent
Chap 4: Prevention and Control
Chain of Infection
Pathogen Reservoir
• is the habitat in which an infectious agent
normally lives & grows
• Human: symptomatic or asymptomatic
• Animal: called zoonoses
• Environmental: plants, soil, and water
Chap 4: Prevention and Control
Chain of Infection
Pathogen Reservoir Portal
of exit
• is the path by which an agent leaves the source
host
Chap 4: Prevention and Control
Chain of Infection
Pathogen Reservoir Portal
of exit
Modes of Transmission
Direct
- Direct contact
- Droplet spread
Indirect
- Airborne
- Vehicleborne
- Vectorborne
Transmission
- how pathogens
are passed
Chap 4: Prevention and Control
Chain of Infection
Pathogen Reservoir Portal
of exit
Portal
Transmission of entry
- agent enters
susceptible host
Respiratory
Oral
Skin
Intravenous
Gastrointestinal
Chap 4: Prevention and Control
Chain of Infection
Pathogen Reservoir Portal
of exit
Portal
Transmission of entry
New
Host
- Final link is
a susceptible host
Chap 4: Prevention and Control
Noncommunicable Disease
Model
Your genetic
endowment
Chap 4: Prevention and Control
Noncommunicable Disease
Model
Your genetic
endowment
Behavioral
choices
Chap 4: Prevention and Control
Noncommunicable Disease
Model
Environment
Your genetic
endowment
Behavioral
choices
Air
Pollution
Chap 4: Prevention and Control
Prioritizing Prevention & Control
Efforts
• Leading Causes of Death
• Years of Potential Life Lost
• Economic Cost to Society
Chap 4: Prevention and Control
Prioritizing Prevention and
Control Efforts
• Leading Causes of Death
• Years of Potential Life Lost
• Economic Cost to Society
Chap 4: Prevention and Control
Prevention, Intervention, Control,
and Eradication of Diseases
• Prevention
– primary
– secondary
– tertiary
• Intervention
– which is defined as taking of action during an event
• Control
– general term used in the containment of disease
• Eradication
– total elimination of the disease
Chap 4: Prevention and Control
Levels of Prevention
• Primary Prevention
– is the forestalling of the onset of illness or injury
during the pre-pathogenesis period (before the
disease process begins)
• Secondary Prevention
– is the early diagnosis and prompt treatment of
diseases before the disease becomes advanced and
disability becomes severe
• Tertiary Prevention
– is to retrain, reeducate, and rehabilitate the patient
who has already incurred disability
Chap 4: Prevention and Control
Chapter 4
Epidemiology:
Prevention and
Control of Diseases
and Health Conditions