2014|Facilitator’s Guide
EPIDEMIOLOGY AND
RISK ANALYSIS
This publication was made possible in part through the support provided by the United
States Agency for International Development. The opinions expressed herein are those of
the author(s) and do not necessarily reflect the views of the US Agency for International
Development or the US Government. USAID reserves a royalty-free nonexclusive and
irrevocable right to reproduce, publish, or otherwise use, and to authorize others to use the
work for Government purposes.
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SEAOHUN One Health Course - Facilitator’s Guide
Preface
“One Health” is an important global activity based on the concept that
human, animal and environmental/ecosystem health are interdependent, and
professionals working in these areas best serve the population by collaborating
to better understand all the factors involved in disease transmission,
ecosystem health, the emergence of novel pathogens and emerging zoonotic
agents, as well as environmental contaminants and toxins that are capable of
causing substantial morbidity and mortality, and impacting on socioeconomic
growth, including in less developed countries.
This EPIDEMIOLOGY AND RISK ANALYSIS Module is part of a
complete series of One Health educational and training documents designed
to be used in whole or in part, and to be modified as needed to serve as a
context- and culturally-relevant source of information for teaching
undergraduate students and university graduate students, and for training
workshops focused on One Health professionals responsible for human,
domesticated animal, wildlife and ecosystem/environmental health. The goals
are to:
For more information
about this course, contact:

increase exposure to and improve cross-sectoral and inter-professional
collaboration on key disease surveillance and disease outbreaks;

provide practical strategies useful for field investigations of disease
outbreaks, and a realistic exposure for students and faculty interested
in emerging infectious diseases, including emerging zoonotic
infectious agents, newly identified infectious agents capable of causing
pandemic threats, disease management and public awareness
campaigns, environmental and ecosystem health; and

improve cooperation among national, regional and district-level
government health officials interested in the One Health principle,
along with multilateral health agencies (such as the World Health
Organization [WHO], the Food and Agriculture Organization of the
United Nations [FAO], and the World Organisation for Animal
Health [OIE]), as well as non-governmental organizations (NGOs)
and private industry.
Stanley Fenwick
Regional Technical
Director RESPOND
Stanley_Fenwick@dai.com
Felicia B. Nutter, DVM,
PhD, RESPOND Project
Senior Technical Officer
Tufts University
+1 508 887 4921
Felicia.Nutter@tufts.edu
Roberta Talmage
TRG, Inc.
Organizational
Development & Training
Specialist
Arlington, VA 22203
+1 703-875-8909
rtalmage@trg-inc.com
This complete set of One Health modules can be used individually by
professors and trainers, but all users are encouraged to begin the activity by
consulting the introductory module to provide an appropriate context and
background.
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Module: Epidemiology and Risk Analysis
All of the training material represents contributions by the faculty and leadership of the Southeast Asia
One Health University Network (SEAOHUN), and the input of technical and managerial support from
the partners of the USAID’s RESPOND Project, part of the larger Emerging Pandemic Threats (EPT)
program, including Tufts University, University of Minnesota, Training Resources Group (TRG),
Ecology and Environment, Inc. (E & E), and). Development of these training materials would not have
been possible without the contributions of the following individuals and groups:
Southeast Asia One Health University Network (SEAOHUN)
 Dr. Abu Tholib Aman, Universities Gadjah Mada, Indonesia
 Mr. Irwin Fernandez Chavez, Mahidol University, Thailand
 Dr. Ede Surya Darmawan, Universitas Indonesia, Indonesia
 Dr. Latiffah Hassan, Universiti Putra Malaysia, Malaysia
 Dr. Nongyao Kasatpibal, Chiang Mai University, Thailand
 Dr. Sumalee Lirtmunlikaporn, Chiang Mai University, Thailand
 Dr. Sarmin MP, Universities Gadjah Mada, Indonesia
 Dr. Mohd Rizal Abdul Manaf, Universiti Kenbangsaan Malaysia, Malaysia
 Dr. Roslaini Bin Abd. Majid, Universiti Putra Malaysia, Malaysia
 Dr. Walasinee Moonarmart, Mahidol University, Thailand
 Dr. Pham Hong Ngan, Hanoi University of Agriculture, Thailand
 Dr. Mohd Sham Bin Othman, Universiti Kenbangsaan Malaysia, Malaysia
 Dr. Surachai Pikulkaew, Chiang Mai University, Thailand
 Dr. Trioso Purnawarman, Bogor Agricultural University, Indonesia
 Dr. Agik Suprayog, Bogor Agricultural University, Indonesia
 Dr. Metawee Thongdee, Mahidol University, Thailand
 Dr. Kriangkrai Thongkorn, Chiang Mai University, Thailand
 Mr. Luu Quoc Toan, Hanoi School of Public Health, Thailand
 Dr. Ronald Enrique Morales Vargas, Mahidol University, Thailand
 Ms. Le Thi Thanh Xuan, Hanoi Medical University/Institute for Preventive Medicine and Public Health,
Thailand
RESPOND Project, USAID Emerging Pandemic Threats (EPT) Program
Development Alternatives International (DAI): Dr. Douglas Hatch, Ms. Pornthip Rujisatian
Environment and Ecology, Inc. (E&E): Ms. Louise Flynn
University of Minnesota: Dr. Jeein Chung, Dr. Karin Hamilton
Tufts University: Dr. Stanley Fenwick, Dr. Raymond Hyatt, Dr. Felicia Nutter, Dr. Jennifer Steele
Training Resources, Inc. (TRG): Ms. Kimberly Kennedy, Ms. Roberta Talmage
The following attribution should be used by anyone copying materials or content from the One Health
modules series:
One Health Educational Module, Southeast Asia One Health Network (SEAOHUN), 2014
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SEAOHUN One Health Course - Facilitator’s Guide
Module: Epidemiology and Risk Analysis
Module Description Epidemiology, epizootiology and population health are all terms describing the
and Learning
study of health and disease in populations, as distinct from individuals. Risk
Outcomes
analysis is a systematic approach to evaluating both the likelihood of
occurrence and the magnitude of impact if a particular adverse event occurs,
and taking steps to mitigate that risk and communicate with relevant
stakeholders and populations. Epidemiology and risk analysis are both
important to the practice of the One Health approach, and professional health
science programs incorporate these topics to some degree in their curricula.
Recognizing that a One Health approach is broad and includes many
disciplines distinct from health sciences (such as economics, social sciences,
law and policy and many others), this module is designed to introduce those
with little or no background in epidemiology to the history, concepts, theories,
terminology and practice of epidemiology to improve their ability to
collaborate with epidemiologists. Key outcomes of this module are the abilities
to:
 Define epidemiology and the basic terminology and concepts used in
epidemiology.
 Explain critical components of the practice of epidemiology.
 Explain the major components in and the process of disease risk analysis,
and how disease risk analysis links science to policy.
Target Learner
Large portions of this module are adapted from the training package “E is for
Epi,” developed by the University of North Carolina Center for Public Health
Preparedness and available online at cphp.sph.unc.edu.
Undergraduate and Graduate University Students;
One Health Partners, Practitioners, and Professionals
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Module: Epidemiology and Risk Analysis
Module Competencies
Competency #1
Define epidemiology and
the basic terminology and
concepts used in
epidemiology.
Competency #2
Explain critical
components of the practice
of epidemiology.
Learning Objectives to Develop Competency
Explain epidemiological terms and concepts by being able to:
 Define epidemiology and public health.
 List the core human and veterinary public health functions.
 Explain the concept of causal webs and the interactions
among host, environment and agent.
Learning Objectives to Develop Competency
Explain critical components in the practice of epidemiology, including
being able to:






Competency #3
Explain the major
components in and the
process of disease risk
analysis and how disease
risk analysis links science to
policy.
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Describe how epidemiology is used by human, animal and
environmental health professionals.
Identify some of the diverse specialties in the field of
epidemiology.
List the different types of epidemiological studies and the
advantages and disadvantages of each.
List the steps to follow in a disease outbreak investigation.
Explain the general principles of surveillance and the
challenges associated with collecting and interpreting data.
Read a peer-reviewed, published epidemiologic study and
explain the major “take home” message of the results.
Learning Objectives to Develop Competency

Understand the purpose and basic terminology of risk
analysis.

Describe the components of the risk analysis process.

Use examples of risk analysis for selected zoonotic infectious
diseases.

Explain how some of the more commonly recognized risk
analysis frameworks are used.
SEAOHUN One Health Course - Facilitator’s Guide
Module Overview
Time
Topic

15 Minutes
Introduction




Epidemiology is a Basic Public Health
30–45 Minutes
Science



60 Minutes
Epidemiology in Practice: History and
Examples



60 Minutes
Epidemiological Tools and Methods




60 Minutes
Epidemiology Partners and Resources





60 Minutes
60 Minutes
Descriptive Epidemiology
Analytic Epidemiology



Materials
Computer, LCD projector,
screen/blank wall
Module PowerPoint
Student Guide
Computer, LCD projector,
screen/blank wall
PowerPoint Slides –
Epidemiology is a Basic Public
Health Science
Flipcharts/stands or whiteboards,
pens for optional activity
Student Guide
Computer, LCD projector,
screen/blank wall
PowerPoint Slides –
Epidemiology in Practice
Student Guide
Computer, LCD projector,
screen/blank wall
PowerPoint Slide – Epidemiology
Tools and Methods
Internet access (optional)
Student Guide
Computer, LCD projector,
screen/blank wall
PowerPoint Slide – Epidemiology
Partners and Resources
Internet access (optional)
Student Guide
Computer, LCD projector,
screen/blank wall
Power Point Slides – Descriptive
Epidemiology
Flipcharts or whiteboard and
markers, or projected computer
screen
Student Guide
Computer, LCD projector,
screen/blank wall
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Module: Epidemiology and Risk Analysis




60 Minutes
60–180
Minutes
180 Minutes
Statistical Measures in Epidemiology
PECOT: Teaching Critical Appraisal of
Published Epidemiology Literature
Introduction to Disease Surveillance








90 Minutes
The Contagious Classroom: An Outbreak
Investigation



60–120
Minutes
Introduction to Disease Risk Analysis


Variable
120 Minutes
(view film)
120 Minutes
(classroom
debrief)
Disease Risk Analysis: Field Exercise for
Risk Assessment
Optional: Review Vocabulary and Concepts
by Watching Contagion






60 Minutes
Learning Reflections and Evaluation

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Power Point Slides – Analytic
Epidemiology
Flipcharts or whiteboard and
markers, or projected computer
screen
Student Guide
Computer, LCD projector,
screen/blank wall
Power Point Slides – Statistical
Measures in Epidemiology
Student Guide
Computer, LCD projector,
screen/blank wall
Student Guide
Computer, LCD projector,
screen/blank wall
Internet access for optional
exercise
Student Guide
Computer, LCD projector,
screen/blank wall
See facilitator notes for special
supplies needed
Computer, LCD projector,
screen/blank wall
Student Guide
Computer, LCD projector,
screen/blank wall
See facilitator notes
Student Guide
Access to DVD or streaming copy
of movie
Computer, LCD projector,
screen/blank wall
Internet access if streaming the
movie in class Student Guide
Computer, LCD projector,
screen/blank wall
Student Guide
SEAOHUN One Health Course - Facilitator’s Guide
Facilitator Background Resources
Bonita, Ruth; Beaglehole, R; Kjellstrom, T. 2006. Basic epidemiology. World Health Organization, Geneva.
Available free online: http://apps.who.int/iris/handle/10665/43541.
European Environmental Agency. Introduction to Risk Assessment Concepts. Available freely online at
http://www.eea.europa.eu.
Food and Agriculture Organization of the United Nations (FAO). The Basics of Risk Assessment. Available
freely online at www.fao.org.
International Union for Conservation of Nature and the World Organisation for Animal Health (IUCN
and OIE). 2014. Wildlife Disease Risk Analysis: Handbook of Procedures and Guidelines. Available online
from www.oie.int.
Office International des epizooties (OIE) 2010. Handbook on Import Risk Analysis for Animals and Animal
Products; Introduction and qualitative risk analysis.
Available online from www.oie.int.
National Research Council. Sustaining Global Surveillance and Response to Emerging Zoonotic Diseases.
Washington, DC: The National Academies Press, 2009. Available free online at www.nap.edu.
Ng V, Sargeant JM (2013) A Quantitative Approach to the Prioritization of Zoonotic Diseases in North America: A
Health Professionals’ Perspective. PLoS ONE 8(8): e72172. doi:10.1371/journal.pone.0072172. Available
free online at http://www.plosone.org.
U.S. General Accounting Office (GAO). West Nile Virus Outbreak – Lessons for Public Health Preparedness.
September 2000. GAO/HEHS-00-180. Available free online at
http://www.gao.gov/products/GAO/HEHS-00-180.
Veterinarians Without Borders. One Health for One World: A Compendium of Case Studies. Available free
online at http://www.onehealthinitiative.com.
World Bank. People, Pathogens and Our Planet. Volume 1: Towards a One Health Approach for Controlling Zoonotic
Diseases. Report no. 50833-GLB. 2010. Available online at: http://www.worldbank.org.
World Health Organization (WHO). 2005. Outbreak Communication Guidelines. Available online at
Institutional Repository for Information Sharing (IRIS), WHO:
http://apps.who.int/iris/handle/10665/69369.
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Module: Epidemiology and Risk Analysis
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SEAOHUN One Health Course - Facilitator’s Guide
INTRODUCTION
Learning Objective:
Gain an understanding of the purpose and structure of the module.
Type of Learning:
Presentation
Timing:
15 Minutes
Equipment and
Materials:



Computer, LCD projector, screen/blank wall
PowerPoint Slides – Introduction
Student Guide
Detailed Facilitator Notes
15 Minutes Module Overview
Give a brief overview of the module competencies, activities and schedule.
Lecture
Epidemiology and risk analysis are both important to the practice of
the One Health approach, and professional health science programs
regularly incorporate these topics to some degree in their curricula.
Recognizing that a One Health approach is broad on and includes
many disciplines distinct from health sciences (such as economics,
social sciences, law and policy and many others), this module is
designed to introduce individuals with little or no epidemiological
background to the history, concepts, theories, terminology and practice
of epidemiology, to enhance their education on key public health issues
and to improve their capacity to collaborate with epidemiologists. Key
outcomes of this module are the abilities to:



Define epidemiology and the basic terminology and concepts
used in epidemiology.
Explain critical components of the practice of epidemiology.
Explain the major components in and the process of disease
risk analysis, and how disease risk analysis links science to
health policy.
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SEAOHUN One Health Course - Facilitator’s Guide
EPIDEMIOLOGY IS A BASIC PUBLIC HEALTH SCIENCE
Learning Objectives:
Type of Learning:
Timing:
Equipment and
Materials:


Define epidemiology.
List the critical one-word questions that are central to the practice of
epidemiology.
 Give examples of useful applications of epidemiological principles.
 Explain what is meant by the epidemiologic triad and the web of
causation.
 List the core functions of human public health and of veterinary public
health activities.
Presentation, Large group brainstorming
30–45 Minutes
 Computer, LCD projector, screen/blank wall
 Module PowerPoint
 Flipcharts or whiteboards, and pens (Optional Activity)
 Student Guide
Detailed Facilitator Notes
30 Minutes Detailed facilitator notes are also included in the notes section of the
PowerPoint slides for this session.
Lecture
This session introduces the learners to basic background information on
epidemiology and its relationship to human and veterinary public health. For
more detailed material on public health, please refer to the Public Health
Module.
Explain that the practice of epidemiology asks and seeks to answer seemingly
simple questions about disease causation and risk – Who/Which? When?
How? Where? and Why? – and that developing complete answers to those
questions can be an arduous task.
Reinforce the similarities and overlaps between human and veterinary public
health, and the common methods and strategies that epidemiology creates.
15 Minutes Ask the learners to suggest several infectious diseases they know of that are
shared by humans and animals (zoonoses), or provide options for them to
choose from, e.g., rabies, Nipah virus, highly pathogenic avian influenza,
Large Group
leptospirosis, and so on.
Brainstorm
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Module: Epidemiology and Risk Analysis
Using the flipcharts, whiteboard or projected computer, ask the learners to
answer the basic one-word epidemiologic questions for the chosen diseases.
 Who/Which?
 When?
 How?
 Where?
Once those questions are answered, ask the learners to help complete basic
epidemiologic triads or webs of causation. Discuss how these factors
influence the occurrence of disease, and how these factors could be used to
control an outbreak of the disease.
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SEAOHUN One Health Course - Facilitator’s Guide
EPIDEMIOLOGY IN PRACTICE: HISTORY AND EXAMPLES
Learning Objective: 

Type of Learning:
Timing:
Equipment and
Materials:
Identify some of the diverse specialties in the field of epidemiology.
Describe how epidemiology is used by human, animal and environmental
health professionals.
Presentation
60 Minutes



Computer, LCD projector, screen/blank wall
Module PowerPoint
Student Guide
Detailed Facilitator Notes
60 Minutes Detailed facilitator notes are included in the notes section of the PowerPoint
slides for this session.
Lecture
In this session, we take a brief look at the diverse specialties within the field of
epidemiology and how these are related to the focus of this module, which is
zoonotic infectious diseases.
We also briefly explore the history of the development of modern
epidemiology and two examples of success stories of global disease
eradication, one human and one animal disease.
Finally, we look at two recent outbreak examples and the role of epidemiology
in outbreak investigation.
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Module: Epidemiology and Risk Analysis
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SEAOHUN One Health Course - Facilitator’s Guide
EPIDEMIOLOGICAL TOOLS AND METHODS
Learning Objective:

List methods that can be used for the epidemiological assessment of a
health problem.

Identify ways that public health laboratories carry out epidemiological
functions.

Identify ways that data can be collected during an epidemiological
investigation.
Type of Learning:
Timing:
Presentation
60 Minutes
Equipment and
Materials:




Pre-Class
Assignment
Computer, LCD projector, screen/blank wall
Module PowerPoint
Student Guide
Research – Infectious Disease Surveillance Data
Detailed Facilitator Notes
Pre-work
Ask students to look for various types of images (maps, graphs, charts, tables)
that show infectious disease surveillance data and to bring several examples
with them to class. If there is internet access in the classroom and students
will have access to computers or smartphones, this search may also be done as
a classroom activity.
Alternatively, the instructor may choose several images showing different
methods of representing disease surveillance system data to share and discuss
in class (see slides on Disease Surveillance Data Graphs and Surveillance Data
Maps for examples)
Good sources include Google Images, WHO, OIE, FAO, HealthMap, and
national (including CDC), and state or local health departments.
30 Minutes More detailed facilitator notes are included in the notes section of the
PowerPoint slides for this session.
Lecture
In this session, we explore core epidemiological methods and the relationships
between human and veterinary public health laboratories, disease surveillance
systems and public health decision-making.
Core to this session is the understanding that disease surveillance is defined as
the ongoing, systematic collection, analysis and interpretation of data to
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Module: Epidemiology and Risk Analysis
support decision-making and improved management of health programs.
It is also important to reinforce that disease surveillance systems should
function as feedback loops and that they can quickly become complex,
generating massive amounts of data. Various technologies help to support
surveillance systems.
30 Minutes After the slide session finishes, ask students to share examples of different
ways to display disease surveillance data, or the instructor may share preselected images. Ask students to discuss what the different types of displays
Large Group
help to highlight. For example, maps highlight location and can clarify spatial
Activity
clusters of cases, chains of transmission, and so on. Graphs and charts are
more effective for showing trends over time, highlighting differences in
patient/case characteristics (e.g., age, sex, occupational exposures, etc.).
Particularly useful are examples of the same data displayed in different ways.
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SEAOHUN One Health Course - Facilitator’s Guide
EPIDEMIOLOGY PARTNERS AND RESOURCES
Learning Objective:
Type of Learning:
Timing:
Equipment and
Materials:

Identify allied health and community partners in the practice of
epidemiology.
 List ways in which epidemiologists work with the media and the five
components of the WHO Outbreak Communication Guidelines.
 Describe how the WHO, OIE, FAO and CDC serve as resources for
training, technical support, and surveillance and reporting of epidemiological
data.
Presentation
60 Minutes




Computer, LCD projector, screen/blank wall
Flipchart or whiteboard with markers
Module PowerPoint
Student Guide
Detailed Facilitator Notes
Pre-work
Ask students to look for various types of reports, preferably in the local and
national media (print, television, radio), related to health and disease. If there
is internet access in the classroom and students will have access to computers
or smartphones, this search may also be done as a classroom activity.
Alternatively, the instructor may choose to bring in several recent examples to
share and discuss in class.
60 Minutes More detailed facilitator notes are included in the notes section of the
PowerPoint slides for this session.
Lecture
Large Group
Discussion
During the segment, show examples of both effective and ineffective
communications. Ask the students to share their thoughts on which of the
following WHO Guidelines are being met (or not) by the various examples.
Once all the examples in the slide set have been shared, the students and/or
instructor may share and discuss additional examples.
WHO Guidelines on Risk Communication during a crisis:
1. Trust
The overriding goal for outbreak communication is to communicate with the
public in ways that build, maintain or restore trust. This is true across cultures,
political systems and level of country development.
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Module: Epidemiology and Risk Analysis
2. Announcing early
The parameters of trust are established in the outbreak’s first official
announcement. This message’s timing, candor and comprehensiveness may
make it the most important of all outbreak communications.
3. Transparency
Maintaining the public’s trust throughout an outbreak requires transparency
(i.e., communication that is candid, easily understood, complete and factually
accurate). Transparency characterizes the relationship between the outbreak
managers and the public. It allows the public to “view” the informationgathering, risk-assessing and decision-making processes associated with
outbreak control.
4. The public
Understanding the public is critical to effective communication. It is usually
difficult to change pre-existing beliefs unless those beliefs are explicitly
addressed. It is nearly impossible to design successful messages that bridge the
gap between the expert and the public without knowing what the public
thinks.
5. Planning
The decisions and actions of public health officials have more effect on trust
and public risk perception than communication. There is risk communication
impact in everything outbreak control managers do, not just in what is said.
Therefore, risk communication is most effective when it is integrated with risk
analysis and risk management. (We will cover risk analysis in a later session in
this module). Risk communication should be incorporated into preparedness
planning for major events and in all aspects of an outbreak response.
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SEAOHUN One Health Course - Facilitator’s Guide
DESCRIPTIVE EPIDEMIOLOGY
Learning Objective:
Type of Learning:
Timing:
Equipment and
Materials:



Define descriptive epidemiology.
List the two major descriptive epidemiological study designs.
List examples of the use of descriptive data.
Presentation, Large Group Exercise
60 Minutes




Computer, LCD projector, screen/blank wall
Flipchart or whiteboard with markers
Module PowerPoint
Student Guide
Detailed Facilitator Notes
30 Minutes
Lecture
In this session, we will begin to examine the differences between descriptive
epidemiology and analytic epidemiology, with a focus on descriptive
epidemiology. Descriptive epidemiology answers the simple questions
who/which, what, when, where, and how much.
30 Minutes
Large Group
Activity
More detailed facilitator notes are included in the notes section of the
PowerPoint slides for this session.
Using the flipcharts, whiteboard or computer screen, ask students to come up
with examples of diseases illustrating the following characteristics of
descriptive epidemiology:

Diseases that have different temporal/seasonal patterns of occurrence
(for example, malaria and other mosquito-borne diseases during rainy
seasons, influenza and so on)
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Module: Epidemiology and Risk Analysis



Diseases with different spatial patterns of occurrence
Diseases with different patterns of occurrence by age (young, old) and
sex (male, female)
Brainstorm about lists of diseases that the students consider epidemic.
Are there both recent and historical examples (SARS vs. MERS
coronavirus, canine rabies, “Spanish flu” and avian influenza, etc.)
Wrap up by examining how much the students already know about the
determinants of disease and the patterns of disease occurrence, even though
they may not be epidemiologists.
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SEAOHUN One Health Course - Facilitator’s Guide
ANALYTIC EPIDEMIOLOGY
Learning
Objectives:
Type of Learning:
Timing:
Equipment and
Materials:
 Define analytic epidemiology.
 List three types of observational study designs.
Presentation, Large Group Exercise
60 Minutes




Computer, LCD projector, screen/blank wall
Flipchart or whiteboard with markers
Module PowerPoint
Student Guide
Detailed Facilitator Notes
30 Minutes
Lecture
More detailed facilitator notes are included in the notes section of the
PowerPoint slides for this session.
In this session, we will focus on analytic epidemiology, which seeks to answer
the why and how questions of disease occurrence.
The major difference between descriptive and analytic observational studies is
that there are COMPARISON groups in analytic studies.
Three main types of analytic study designs are:
 Cross-sectional
 Case-control
 Cohort
We will look at each of these study designs in more detail.
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Module: Epidemiology and Risk Analysis
30 Minutes
Large Group
Activity
Ask the students to discuss the following types of zoonotic diseases, and
decide which type of observational study (from the choice within descriptive
and analytic study designs) is best suited to investigation of:
 a newly emerged zoonosis.
 a zoonosis with a long incubation period.
 disease prevalence and incidence.
 a zoonosis in a remote or inaccessible area.
Have the students explain the reasons for their answers and discuss how the
studies could be carried out. Explained below are the strengths and
weaknesses of each study design and some examples of when each design is
most useful.
Case studies
Descriptive, detailed study of a limited number of cases, good for rare
diseases, no control (i.e., comparison) group, not usually representative of the
general population, may help to generate hypotheses about causation of
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SEAOHUN One Health Course - Facilitator’s Guide
disease. An example would be a description of a rare disease such as human
with illness (“case”) due to highly pathogenic avian influenza (HPAI),
describing the case and the factors associated with the case in detail.
Cross-sectional studies
Groups of animals or humans are selected at one point in time as a (random)
cross-section of the population. Prevalence of disease is recorded from data
collected during surveys.


Advantages: Cross-sectional studies are relatively quick to conduct
and their cost is moderate, compared with other study designs. This
type of study is good for high prevalence diseases, and the findings
are generally designed to be representative of the population being
studied.
Disadvantages: Cross-sectional studies can only estimate prevalence
of disease, not incidence. They provide little information on cause and
effect, or the outcome of disease control programs.
Case-control studies (retrospective)
Animals or humans are selected and grouped according to the presence (case)
or absence (control) of disease, which may be “clinical” disease, or may also
be confirmed by laboratory diagnostics. Data about exposure to risk factors
are acquired retrospectively (records, memory) after selection, usually by using
standardized questionnaires, and exposures are compared in the two groups.
 Advantages: This method is good for studying rare diseases or
diseases with a long incubation period. They can be quicker and
cheaper to run than the other study types.
 Disadvantages: They do not provide information about incidence or
prevalence of disease. The study relies on collected data, and bias is
often a problem.
Cohort studies (longitudinal – prospective or retrospective)
Animals or humans are followed over time, grouped according to exposure to
a risk factor. The outcome of interest (Disease: Yes or No) is noted, and the
rate of disease in compared in the two groups (exposed vs. unexposed).


Advantages: Cohort studies measure disease incidence and may be
useful for determining the outcome of disease control programs, as
well as estimating rates of disease based on exposure.
Disadvantages: Unfortunately, they are expensive and may require a
long follow-up period. Large groups are necessary for investigating
rare diseases. Losses to follow-up can become an important problem.
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Module: Epidemiology and Risk Analysis
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SEAOHUN One Health Course - Facilitator’s Guide
STATISTICAL MEASURES IN EPIDEMIOLOGY
Learning Objective:


Type of Learning:
Timing:
Equipment and
Materials:
Define the most common statistical frequency measures used in infectious
disease epidemiology.
Construct a frequency distribution.
Lecture
60 Minutes
 Computer, LCD projector, screen/blank wall
 Flipchart or whiteboard with markers
 Module PowerPoint
 Student Guide
Detailed Facilitator Notes
60 Minutes
Lecture
More detailed facilitator notes are included in the notes section of the
PowerPoint slides for this session.
In this session, we will look at the most fundamental measures in
epidemiology, including ratios, proportions, incidence, prevalence and rates.
Statistics summarize the data collected through disease surveillance or an
outbreak investigation, so we can learn from the data. Calculating statistics
helps us:
 Describe risk.
 Make comparisons.
 Identify high-risk groups.
 Develop hypotheses about the cause(s) of disease.
Page | 25
Module: Epidemiology and Risk Analysis
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SEAOHUN One Health Course - Facilitator’s Guide
PECOT
Teaching Critical Appraisal of Published Epidemiology Literature
Learning Objective:
Type of Learning:
Timing:
Equipment and
Materials:

Explain the basic components of observational epidemiological studies from
published peer-reviewed articles.
 Optional: Use the PECOT method to assess completeness and accuracy of
popular press reports of epidemiologic studies.
Presentation; Small Group Work; Large Group Debrief
60–180 Minutes




Computer, LCD projector, screen/blank wall
Flipchart or whiteboard with markers
Module PowerPoint
Student Guide
Detailed Facilitator Notes
30 Minutes
Lecture
 Note: Adapted from Rod Jackson, Center for Evidence Based
Medicine, University of Oxford, UK, and University of Auckland,
NZ. http://www.cebm.net/index.aspx?o=1083.
Introduce the concepts of critical appraisal of a published article using the
PECOT method and show examples of articles on different
epidemiological study design.
Key reference used in the presentation: Scurr, J. H., Machin, S. J., BaileyKing, S., Mackie, I. J., McDonald, S., and Smith, P. D. C. (2001).
Frequency and prevention of symptomless deep-vein thrombosis in longhaul flights: a randomised trial. The Lancet, 357(9267), 1485-1489.
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Module: Epidemiology and Risk Analysis
30–90
Minutes
Small Group
Activity
For this exercise, divide students into small groups of four to six. In 30minute increments, ask students to read and apply PECOT to various
types of observational studies. Depending upon available time, each group
of students may read and interpret one or more than one study.
Possible references:
Prospective Cohort: Khuntirat, B. P., et. al. (2011). Evidence for
subclinical avian influenza virus infections among rural Thai villagers.
Clinical Infectious Diseases, 53(8), e107–e116.
Retrospective and Prospective Cohort: Moen, A. R., Wouda, W., Mul, M.
F., Graat, E. A. M., and Van Werven, T. (1998). Increased risk of abortion
following Neospora caninum abortion outbreaks: a retrospective and
prospective cohort study in four dairy herds. Theriogenology, 49(7), 1301–
1309.
Corss-sectional: Suwancharoen, D., Chaisakdanugull, Y.,
Thanapongtharm, W., and Yoshida, S. (2013). Serological survey of
leptospirosis in livestock in Thailand. Epidemiology and infection, 141(11),
2269–2277.
Case-Control: Parashar, U. D, et. al. (2000). Case-control study of risk
factors for human infection with a new zoonotic paramyxovirus, Nipah
virus, during a 1998–1999 outbreak of severe encephalitis in Malaysia.
Journal of Infectious Diseases, 181(5), 1755–1759.
30–60 Minutes Depending upon available time and class size, the instructor may choose
to have the entire class debrief together. Groups can share their
interpretations of the studies, and any challenges they had in applying the
Large Group
PECOT/GATE method.
Discussion
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SEAOHUN One Health Course - Facilitator’s Guide
INTRODUCTION TO DISEASE SURVEILLANCE
Learning Objective:
Type of Learning:
Timing:
Equipment and
Materials:

Explain the surveillance “feedback loop” of data and information flow
through local, state and federal channels.
 Describe characteristics of three different methods of surveillance: active,
passive and syndromic.
 List five applications of public health surveillance.
Lecture
180 Minutes




Computer, LCD projector, screen/blank wall
Flipchart or whiteboard with markers
Module PowerPoint
Student Guide
Detailed Facilitator Notes
60 Minutes
Lecture
More detailed facilitator notes are included in the notes section of the
PowerPoint slides for this session.
In this session, we will revisit the concept of surveillance in more detail,
learning about the major surveillance methods (active, passive and syndromic)
and global systems, as well as discussing some of the limitations and
challenges of collecting, analyzing and interpreting surveillance data.
Students will be challenged to quickly apply the concepts reviewed to examine
some existing global surveillance systems and design their own SMART
surveillance plans.
60 Minutes
Small Group
Activity
 Note: This activity is also found in the Infectious Disease Management
Module, with slight modifications.
Divide students into groups of four to six (or fewer) and assign each group a
disease surveillance website to explore.
 US CDC – http://www.cdc.gov/surveillancepractice/
 WHO Global Influenza Surveillance and Response System
http://www.who.int/influenza/gisrs_laboratory/en/
 WHO Global Outbreak Alert and Response Network (GOARN)
http://www.who.int/csr/outbreaknetwork/en/
 OIE – World Animal Health Information System
http://www.oie.int/animal-health-in-the-world/the-world-animalPage | 29
Module: Epidemiology and Risk Analysis



health-information-system/the-oie-data-system/
FAO – EMPRES-I http://empres-i.fao.org/eipws3g/#h=0
European CDC http://www.ecdc.europa.eu/en/activities/surveillance/Pages/index.a
spx
HealthMap - http://healthmap.org/en/
Ask the students to examine the surveillance system based on the basic
concepts of surveillance evaluation and determine if the surveillance websites
have a well-organized plan for surveillance data collection, procedures and
methods to ensure the validity and reliability of data.
After assessing the website, students should choose a zoonotic disease and
create a plan for data collection, including procedures and techniques covered
in the PowerPoint presentation.
60 Minutes
Large Group
Debrief
Have each group display their evaluation plans for their chosen zoonotic
disease.
Then, as a large group, discuss the similarities and differences among the
plans in terms of the evaluation criteria: simplicity, flexibility, acceptability,
sensitivity, specificity, accuracy, positive predictive value, negative predictive
value, representativeness, sustainability and timeliness.
Have the large group debrief on the SMART surveillance system for zoonotic
diseases by asking the following questions, “How did each group’s plan
include the aspects of SMART?”
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SEAOHUN One Health Course - Facilitator’s Guide
THE CONTAGIOUS CLASSROOM:
An Outbreak Investigation
Learning Objective:
Type of Learning:
Timing:
Equipment and
Materials:
 Experience a disease outbreak and investigation.
 List the typical steps followed in a disease outbreak investigation.
Game, Large Group Debrief
90 Minutes









Computer, LCD projector, screen/blank wall
Flipchart or whiteboard with markers
Module PowerPoint
Student Guides
Computers (for students)
Test tube or cups, and dropper/transfer pipette for each participant.
Distilled water
0.1 molar sodium hydroxide (NaOH)
Phenolphthalein indicator solution, dissolved in alcohol and diluted in water
(pH indicator)
Detailed Facilitator Notes
60 Minutes
Game
Simulating an Epidemic
From bubonic plague to malaria to leptospirosis, scientists and public health
officials have struggled to understand and contain the spread of infectious
diseases. Using simple reagents, participants will simulate the spread of a
simple imaginary disease in order to explore some factors that affect the rate
of infection, the challenges of epidemiology, and methods to investigate and
describe disease outbreaks.

Prepare the containers prior to the activity: Fill one container halfway with
0.1 molar NaOH and fill the rest of the containers halfway with distilled
water. You may number each container for clarity and to illustrate
“confidentiality” of data collection as the exercise unfolds.
- If you have a large group (30–35 or more) you may want to begin

with two test tubes containing NaOH. The final number of
“infected” test tubes will vary depending on (1) the number of trades
and (2) how many trades occur between two already infected tubes.
Let participants know they are going to model the transmission of a
disease by exchanging some of their containers’ contents with that of
other participants. Mention that one of the containers is “infected” with
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Module: Epidemiology and Risk Analysis
an imaginary infectious disease.
CAUTION: NaOH and phenolphthalein can irritate the eyes and skin.
Alert participants to avoid spilling and warn them to NEVER drink
what is in the containers. Also, instruct them to be careful NOT to touch
the other person’s fluid when exchanging drops.



Distribute prepared containers and droppers randomly to the class.
Make a mental note of who receives the test tube(s) containing NaOH.
Have participants walk around the room with their test tubes. When
you say “Stop!” each participant should use a dropper/pipette to trade
fluid (several drops, half a pipette – be specific) with the person
nearest them. Repeat until at least three trades have occurred. Instruct
the participants to record in order the IDs of the people with whom
they traded fluid.
Now it’s time to test for the imaginary infection. Put a drop of
phenolphthalein in each container. If the fluid turns pink, the
container is “infected” with NaOH. How many participants are
now “infected”?
Tracing the Source of Infection
 Now that a portion of the group has been “infected,” put
participants in the role of epidemiologists. Their challenge is to
collect data that will help them trace the path of the epidemic,
locate the original carriers and describe the outbreak using
appropriate terms.
 As a group, use the data to try to deduce which individual was the
original carrier of the disease.
o Why might it be important to locate the source of infection?
o What difficulties arise in trying to collect and interpret data?
Note that the simulated disease has a 100% rate of infection that
appears immediately under testing. Some infections, such as HIV
and chicken pox, can remain dormant in the body for a long
time. Others, such as Ebola, kill the host rapidly.
o How might each of these factors affect the spread of disease and
the ability to identify carriers?
 A possible method to find “patient zero” is to have each participant
write his or her container number or name on the board and
underneath it the names or numbers of participants with whom
he or she exchanged fluids in the order in which the exchanges
occurred. Then, as a group, highlight the names of the currently
“infected” (shown in bold in sample).
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SEAOHUN One Health Course - Facilitator’s Guide


This visual representation can help clarify which participants may have
infected one another, and in what order. Participants who “test
positive” and find that everyone with whom they traded also tested
positive may be original carriers of the disease. It is likely that there will
be several candidates for “patient zero.” Cross-checking the history of
each contact can narrow the field, but probably not to fewer than two
candidates.
If participants are unable to reach a clear conclusion, the exercise will
raise useful questions about the challenges facing real epidemiologists
as they try to trace the sources of an infection.
Additional Options
The data gathered on the classroom “outbreak” can be used in a variety of
ways. Some examples include:
 Have students calculate incidence (for example, number of cases per
round of contact; you may imagine that each round represents a day, a
week, etc.).
 Have students calculate prevalence.
 Discuss “point source” infections.
 Calculate basic reproductive rate of the infection (how many cases, on
average, did each case infect?).
 Discuss the role of “super spreaders” in a disease outbreak.
Adaptation for a Large Classroom
If the class has more than 30 people, it can be difficult or take too long to
have all of them participate in the outbreak. To still engage the rest of the
class, you can divide as follows:
 30 students are the population involved in the outbreak and function as
described above.
 Two or three students can be the data analysts who will record data
collected from the population on their computers.
 The remaining students can be an epidemiology team that works with
the data analysts to decide how to study the population and determine
the index case.
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Module: Epidemiology and Risk Analysis
Sample Chart Tracing Infection
Person 1
Person 2
Person 3
Person 4
Person 5
Person 6
Person 7
Contact 1
Contact 2
Contact 3
30 Minutes
Large Group
Debrief
To conclude the Contagious Classroom exercise, ask the students to list the
steps that they followed in the outbreak investigation, in order by writing on a
flipchart, whiteboard, or using a projected computer screen. Then ask them to
review the list and decide if any critical steps are missing. If so, add the steps.
Next, ask them to list the major objectives of a disease outbreak investigation.
Similarly, have them review and modify the list as a group.
Then review with the students the following objectives and steps in a typical
outbreak investigation (slides in PowerPoint deck).
Disease outbreak investigation
The objectives of an outbreak investigation are to:

Stop progression of the disease.

Determine the causes of the outbreak.

Control the outbreak.

Prevent future outbreaks.
Steps to follow:
1. Verify the outbreak.


What is the disease (initial case definition, eventual diagnosis),
how severe is it and is it a true excess of disease?
Identify and review potentially zoonotic incidents, looking at
acute clusters or outbreaks, increasing trends of known infections
or syndromes, or new infections or undiagnosed syndromes.
2. Describe the clinical signs of the disease.
Identify characteristics common to all the affected members and how
these diseased individuals can be distinguished from unaffected
individuals.
3. Define the problem in terms of time, place and population affected.
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SEAOHUN One Health Course - Facilitator’s Guide
Assess the risk to human and animal health and whether it is a possible
zoonotic risk.
4. Enhance surveillance of humans and animals in the affected area and
surrounding area. This helps identify additional cases.
5. Describe the outbreak.
Collect historical data and compare affected and unaffected individuals.
Plot an epidemic curve to determine source, incubation and spread of the
disease agent. Map the data, human and animal movement, barriers to
movement, etc.
6. Develop hypotheses about the cause.
7. Perform analytical studies on collected data to identify risk factors.
Identify high and low risk factors.
8. Disease control
Using the above information a control strategy can be implemented even
if the infectious agent has not been positively identified. Further
investigation into the cause of the disease may be necessary.
9. Prevention strategies
This includes communication, education, etc.
10. Adjust surveillance and monitoring programs accordingly.
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Module: Epidemiology and Risk Analysis
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SEAOHUN One Health Course - Facilitator’s Guide
INTRODUCTION TO DISEASE RISK ANALYSIS
Learning Objective:
Type of Learning:
Timing:
Equipment and
Materials:




Understand the purpose and basic terminology of risk analysis.
Describe the components of the risk analysis process.
Give some applications of risk analysis for zoonotic infectious diseases.
Explain some of the commonly recognized and used risk analysis
frameworks.
Presentation; Small Group Exercise; Large Group Debrief
60–120 Minutes




Computer, LCD projector, screen/blank wall
Flipchart or whiteboard with markers
Module PowerPoint
Student Guide
Detailed Facilitator Notes
60 Minutes
Lecture
 Note: For additional information and teaching options, including an
exercise in Quantitative Microbial Risk Assessment, please review the
materials on risk assessment in the Infectious Disease Management
Module.
More detailed facilitator notes are included in the notes section of the
PowerPoint slides for this session.
In this session, we will examine the process of risk analysis, which:
• Is a logical process to support decision-making under uncertain
conditions, when information is incomplete.
• Adds science to policy to help minimize risk and its impacts.
• Communicates risk to stakeholders.
Risk analysis is iterative and involves identifying risks (also called hazards),
framing a question, developing a model, adding data to that model
(qualitative, quantitative or somewhere in between) and then running the
model. The findings and results of the analysis are normally interpreted
cautiously; for example, these are reviewed in relation to such issues as
biological plausibility, evidence of any dose-response effect(s), temporality
(i.e., assuring the implicated exposure occurred prior to disease onset) and
consistency with the current literature to assure that the hypothesis about
disease causation being proposed is logical and based on “good” scientific
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Module: Epidemiology and Risk Analysis
principles or best practices, etc. This helps highlight gaps in data, critical
points in the risk pathway and options for risk mitigation.
There are multiple internationally recognized frameworks for completing risk
analyses and we’ll look at some of them. All are basically the same, with
slightly different terminology.
30–60
Minutes
Small
Group
Activity
Instructors may assign small groups of students to read and interpret
published articles on disease risk analysis. Several potential example references
are listed below.
You have a research article that applies Disease Risk Analysis. Please read it
and answer questions bellow:
 What is the framing question?
 What is/are the hazard/hazards identified?
 What are risks?
 Is the risk analysis qualitative, quantitative or both?
 Who are the stakeholders identified?
 Who will be informed of the results?
 How could result be applied?
Results may be shared and compared among groups or presented back to the
class and discussed, depending upon instructor preference, available time and
class size.
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SEAOHUN One Health Course - Facilitator’s Guide
Possible References:
 de Man, H., Bouwknegt, M., van Heijnsbergen, E., Leenen, E. J. T.
M., van Knapen, F. and de Roda Husman, A. M. (2014). Health
risk assessment for splash parks that use rainwater as source water.
Water Research.

Dom, N. C., Ahmad, A. H., Latif, Z. A., Ismail, R. and Pradhan, B.
(2013). Coupling of remote sensing data and environmental-related
parameters for dengue transmission risk assessment in Subang Jaya,
Malaysia. Geocarto International, 28(3), 258–272.

Jones‐Engel, L., Engel, G. A., Schillaci, M. A., Lee, B., Heidrich, J.,
Chalise, M. and Kyes, R. C. (2006). Considering human–primate
transmission of measles virus through the prism of risk analysis.
American Journal of Primatology, 68(9), 868–879. Abstract available at:
http://www.ncbi.nlm.nih.gov/pubmed/16900498.


Small
Group
Exercise
60
Minutes
Lau, C. L., Clements, A. C., Skelly, C., Dobson, A. J., Smythe, L. D.,
and Weinstein, P. (2012). Leptospirosis in American Samoa –
estimating and mapping risk using environmental data. PLoS Neglected
Tropical Diseases, 6(5), e1669. Article available free online at:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3362644/.
For this optional exercise, divide students into groups of four to six. Refer to
the instructions for the Quantitative Microbial Risk Assessment in-class
activity in the Infectious Disease Management module.
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Module: Epidemiology and Risk Analysis
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SEAOHUN One Health Course - Facilitator’s Guide
DISEASE RISK ANALYSIS: A FIELD EXERCISE FOR RISK
ASSESSMENT
Learning Objective:

Type of Learning:
Timing:
Equipment and
Materials:


Complete a basic risk assessment for a zoonotic disease in a local
community.
Presentation; Field trip
Variable





Computer, LCD projector, screen/blank wall
Optional Power Point Slides – Instructor to create based on specific field
exercise plans
Student Guide
Logistics for travel to/from field trip site, food/drinks while at site
Maps, cell phones and/or cameras, video cameras if photography and video
capture will be possible.
Ensure that all necessary human and animal subjects protection approvals are
in place.
Ensure that appropriate contact with and permission from community
leaders and local officials has been organized well in advance of the visit.
Detailed Facilitator Notes
30–45
Minutes
Lecture
Small
Group
4–5 per
group
180
Minutes
minimum
Provide an overview of the field trip:
 Purpose of the field trip
 Details on culture, traditions, human and animal population in and
around the local community the students will visit
 Known risk factors of zoonotic diseases
 Livestock and wildlife known to be present in and around the
community
 Any known livestock, wildlife, zoonotic diseases present in
populations
 How zoonotic diseases have influenced local culture or practices
 How to interact with the community
Field Trip
 Students participate in the field trip to a local community or animal farms.
During field trip students take notes on practices observed and all factors
that may influence transmission of zoonotic diseases that could impact
human health, animal health and/or environmental health.
- Have any zoonotic diseases outbreaks occurred in the community? If
yes, focus on this disease.
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Module: Epidemiology and Risk Analysis
- What can you observe in the community (jobs, agriculture, livestock
kept, food consumed, food and water supply, food preservation,
environmental sanitation, waste management, trade and tourism, and
so on).
- What animals (livestock, wildlife, pets…) are present? Management
systems, environment, animal waste management?
- What ecosystem or ecosystems have been noted? Are any known
diseases associated with those ecosystems?
- What factors related to the humans, animals and their environment
may impact zoonotic disease transmission?
- Is there access to human and animal health care?
60–120
Minutes
or more
Large Group
Debrief
Option 1:
As a large group, collaboratively complete a basic risk assessment. It may be
qualitative, quantitative or semi-quantitative, depending upon the time
available for students to conduct a literature search to gather data. Also
depending upon time, risk management and risk communication portions may
also be completed.
Option 2:
Have the students remain in their small groups to complete the basic risk
assessment (and optional risk management and risk communication, as
above). Have each group report back in plenary.
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SEAOHUN One Health Course - Facilitator’s Guide
REVIEW VOCABULARY AND CONCEPTS BY WATCHING
CONTAGION (Optional Activity)
Learning Objective:

Review vocabulary and concepts of epidemiology (and zoonotic infectious
diseases).
May or may not include the following learning objectives (overlaps with
Fundamentals of Infectious Diseases and Infectious Disease Management)
 Explain the progression of a disease within an individual.
 Describe how infections are transmitted from individual to individual.
 Describe the transmission of a disease within a population.
Type of Learning:
Timing:
Equipment and
Materials:
Movie, Presentation and Large Group Debrief
Watch movie (in or outside of class) 120 Minutes
Presentation, Debrief 120 Minutes
 Computer, LCD projector, screen/blank wall
 Flipchart or whiteboard with markers
 Module PowerPoint
 Student Guide
 Access to DVD or streaming copy of movie (Internet access if streaming the
movie in class)
Detailed Facilitator Notes
Pre-work
OR
In Class








Watch Contagion
Prior to watching the movie, distribute the list of vocabulary
words below, and ask the students to complete definitions for
120 Minutes as many as possible while watching the movie. Even if the
term is unfamiliar to them, they should try to infer the
meaning from the context in the movie. No cheating!
Agent
Bacteria
Carrier
Endemic
Enzootic
Epidemic
Epizootic
Fomite/Vehicle






Horizontal
Transmission
Host
Incubation Period
Index case
Infective
Outbreak








Outbreak curve
Pandemic
Parasite
Pathogen
R0
Recovered
Reservoir
Resistant







Susceptible
Transmission
Vaccine
Vector
Vertical
Transmission
Virus
Zoonosis
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Module: Epidemiology and Risk Analysis
120 Minutes More detailed facilitator notes are included in the notes section of the
PowerPoint slides for this session.
 Agent: A factor (e.g., a microorganism or chemical substance) or form of
Large Group
energy whose presence, excessive presence or, in the case of deficiency
Discussion
diseases, relative absence is essential for the occurrence of a disease or
other adverse health outcome.
 Bacteria: A member of a large group of unicellular microorganisms
lacking organelles and an organized nucleus, including some that can
cause disease
 Carrier: An individual who is infected and, although usually has few or
no symptoms of disease, may serve as a reservoir to transmit infection to
others. The term may also apply to an individual who is convalescing and
may have some symptoms, but remains infectious. Duration of the carrier
status may be brief (days) or may last for a prolonged period; e.g., persons
with latent (inactive) tuberculosis (TB) infection are latent carriers who
may experience reactivation of TB after several decades and become
infectious to others if not properly treated. Further, “carrier” may also
apply to an individual with a genetic condition who does not personally
manifest disease, but who may still transmit the gene to offspring. Thus,
the term “silent” carrier may refer to individuals who have no symptoms,
but can transmit an infectious disease or a recessive gene (e.g., sickle cell
anemia trait or alpha thalassemia trait). Thus, silent carriers retain their
infectiousness, while latent carriers are not infectious.
 Endemic/Enzootic: The normal frequency of disease in a population.
There are predictable patterns, e.g., seasonal outbreaks of mosquito-borne
diseases such as malaria or seasonal influenza. Endemic disease indicates
that the agent and host have adapted to each other over time, and the
disease is maintained in a population (without migration or new inputs of
the pathogen); a constantly present disease in a population. For measles
virus, the term is used slightly differently to indicate an infection which
can persist in a population in the long-term without needing to be
reintroduced from outside. Stable endemicity (sometimes referred to as
“endemnicity”) is when the incidence of infection or disease shows no
secular trend for increase or decrease.
 Epidemic/ Epizootic: An increased occurrence of disease compared to
what is expected. It indicates an imbalance among the host, the agent and
the environment and implies a clustering of cases in time and space. A
rapid increase in the levels of an infection. Typical of the microparasitic
infections (with long-lasting immunity and short generation times), an
epidemic is usually heralded by an exponential rise in the number of cases
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SEAOHUN One Health Course - Facilitator’s Guide






in time and a subsequent decline as susceptible numbers are exhausted.
Epidemics may arise from the introduction of a novel pathogen (or strain)
to a previously unexposed (naive) population or as a result of the
regrowth of susceptible numbers some time after a previous epidemic due
to the same infectious agent. For some high priority infectious agents
(e.g., poliovirus), even a single individual with acute paralysis due to wild
poliomyelitis virus infection could be considered an “epidemic,” due to
both the urgent need for preventive measures (polio vaccination
campaign to prevent acute paralysis in other susceptible individuals in the
area) and the fact that up to 100 asymptomatic infections in young
children may occur for each case of paralytic polio infection identified.
Fomite/Vehicle: An inanimate object, including bedding, utensils or
hospital equipment capable of carrying a pathogen and serving as a means
for disease transmission.
Host: The host in which a parasite (macro or micro) reproduces sexually
or asexually. A living organism that is susceptible to or harbors an
infectious agent under natural conditions.
Incubation Period: The time that elapses between initial infection and
the appearance of symptoms of a disease. Not the same as the latent
period.
Index case: The first case of a new disease, or initial person ill (initial
“case”) in a disease outbreak. Also called patient zero.
Infective: Capable of transmitting infection to another host.
Immune: 1) A state in which a host is not susceptible to infection or
disease, or 2) the mechanisms by which this is achieved. Immunity is
normally achieved by an individual through one of three routes:
- Natural or innate immunity is genetically inherited or acquired
through maternal antibody. Innate immunity may also refer to
physiological barriers to infection (e.g., skin, mucous) or
protective mechanisms, such as phagocytosis of bacteria or
viruses by white blood cells, or enzymatic proteins (e.g.,
lysozymes).
- Acquired immunity is conferred after contact with an infectious
agent or antigen; this process involves two types of lymphocytes:
“cell-mediated” immunity (involving T-cells) or “humoral”
immunity (B-cells).
- Artificial immunity is a term that may be used to describe immunity
after vaccination (e.g., “natural” immunity following infection vs.
“artificial” following vaccination.). The term “artificial” may also
be used when passive immunity is transferred (e.g., when human
immunoglobulin is used to treat infant botulism or
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Module: Epidemiology and Risk Analysis
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immunoglobulin is used with vaccine to prevent rabies).
Outbreak: Occurrence of cases of disease in excess of what would
normally be expected in a defined community, geographical area or season.
Similar to the term “epidemic,” perhaps used more commonly for smaller
events. Term may apply to a single case of a high priority infectious
disease (e.g., acute paralytic poliomyelitis case).
Outbreak curve: Also called epidemic curve. A graphical representation,
usually in the form of a histogram, showing the number of incidents of
illness over time.
Pandemic: A widespread epidemic affecting populations in different
countries or continents.
Parasite: Any disease-causing organism; also an organism exhibiting an
obligatory dependence on another organism, its host, which is
detrimental to the host.
- Macroparasites: Typically, the parasitic helminths and arthropods.
In general, parasites that do not multiply within their definitive hosts,
but instead produce transmission stages (eggs and larvae) that pass
into the external environment.
- Microparasites: Typically, viruses, bacteria, fungi and protozoa.
More generally, parasites that multiply within their definitive hosts.
Microparasites are characterized by small size, short generation times
and a tendency to induce immunity to reinfection in those hosts that
survive. The duration of infection is usually short in relation to the
lifespan of the host, but there are important exceptions, such as the
slow viruses.
Pathogen: Infectious, biological agent that causes disease or illness to its
host.
R0: the basic, or intrinsic reproductive rate; a measure of the fitness of
the parasite/pathogen. In microparasites, defined as the expected number
of secondary infections produced in a susceptible population by a single
infective host (with primary infection). In macroparasites, defined as the
number of adult parasites produced by a single adult parasite.
Recovered: An individual who has contracted an infection, developed
symptoms and, after a period of time, is no longer suffering symptoms.
The individual may still be infected, may still be infectious or may be free
from the infectious agent. A recovered individual may have developed
partial, temporary, complete or life-long immunity, or may be susceptible
to infection once again.
Reservoir: Any person, other animal, plant, soil or substance in which an
infectious agent normally lives and multiplies. The reservoir typically
harbors the infectious agent without injury to itself and serves as a source
from which other individuals can be infected. The infectious agent
SEAOHUN One Health Course - Facilitator’s Guide
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primarily depends on the reservoir for its survival. It is from the reservoir
that the infectious substance is transmitted to another susceptible host.
Resistant: Inaccessible to infection by a pathogen; may also refer to
antimicrobial resistance among bacteria.
Susceptible: An individual accessible to or liable to infection by a
pathogen due to lack of immunity to that agent.
Transmission: The process by which a pathogen passes from a source
of infection to a new host. There are two major types: horizontal and
vertical transmission. The majority of transmission processes operate
horizontally.
- Direct transmission: Disease-causing microorganisms spread from
the infected person to the healthy person via direct physical contact
with blood or body fluids. Examples of direct contact are touching,
kissing, sexual contact, contact with oral secretions or contact with
body lesions.
- Horizontal Transmission: Transmission occurring generally within
a population, but not including vertical transmission.
- Vertical Transmission: Conveyance of an infection from a parent
to its unborn offspring. Perinatal infection is a special form of vertical
transmission.
Vector: A living vehicle by which infections are transmitted from one
host to another (for example, a mosquito or tick).
Virus: An infectious agent that typically is noncellular, consists of a
nucleic acid molecule (RNA or DNA) in a protein coat, is too small to be
seen by light microscopy, and is able to multiply only within the living
cells of a host (i.e., classified as an obligate intracellular parasite).
Zoonosis/Zoonoses: Disease(s) that is(are) naturally transmitted
between non-human and human animals.
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Module: Epidemiology and Risk Analysis
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SEAOHUN One Health Course - Facilitator’s Guide
LEARNING REFLECTIONS AND EVALUATION
Learning Objective:

Type of Learning:
To reflect on learnings in the Epidemiology and Risk Analysis
Module.
 To get feedback from participants on what they felt were the
strengths of the module and which areas in the module could be
improved.
Individual Assessment; Group Feedback
Timing:
60 Minutes
Equipment and
Materials:

Student Guide
Detailed Facilitator Notes
Evaluate/
Create
How would you rate your level of the following
Epidemiology and Risk Analysis competencies:
Apply
Individual
Learning
Assessment
Have your students complete the following learning assessment in their
Student Guide. Once they are complete, collect the responses to inform
future deliveries of the module.
Understand
20 Minutes
Define epidemiology and the basic terminology and concepts in
epidemiology.
Explain critical components of the practice of epidemiology.
Explain the major components in and the process of disease risk
analysis and how disease risk analysis links science to policy.
Write down two or three things that you learned from the session. Think
about:
 What was new or surprising to you?
 What have you changed your mind about?
 What are you still unsure about?
 What was interesting to you/what would you like to study in more
detail?
 Are there new behaviors that you will try based on this class?
 What topics from the class will you share with others outside the
class?
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Module: Epidemiology and Risk Analysis
20 Minutes In small groups, have each student share:
 Their key learnings from the module.
Small Group
 How they will apply the concepts, knowledge, skills they gained from
Discussion
the module.
Group
Feedback
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20 Minutes Ask the students:
 What is one element of the module they like/felt was a strength?
 What is one thing in the module they suggest be changed?
 Any additional comments?
SEAOHUN One Health Course - Facilitator’s Guide
RESOURCES FOR STUDENTS
Homework References Available in the Resource Folder
de Man, H., Bouwknegt, M., van Heijnsbergen, E., Leenen, E. J. T. M., van Knapen, F. and de Roda
Husman, A. M. (2014). Health risk assessment for splash parks that use rainwater as source water.
Water Research.
Dom, N. C., Ahmad, A. H., Latif, Z. A., Ismail, R. and Pradhan, B. (2013). Coupling of remote sensing
data and environmental-related parameters for dengue transmission risk assessment in Subang Jaya,
Malaysia. Geocarto International, 28(3), 258–272.
Jones‐Engel, L., Engel, G. A., Schillaci, M. A., Lee, B., Heidrich, J., Chalise, M. and Kyes, R. C. (2006).
Considering human–primate transmission of measles virus through the prism of risk analysis. American
Journal of Primatology, 68(9), 868–879. Abstract available at:
http://www.ncbi.nlm.nih.gov/pubmed/16900498.
Khuntirat, Benjawan P., et. al., Évidence for subclinical avian influenze virus infections among rural Thai villagers,”
Clinical Infectious Diseases, 53(8) (2011)
Lau, C. L., Clements, A. C., Skelly, C., Dobson, A. J., Smythe, L. D., and Weinstein, P. (2012).
Leptospirosis in American Samoa – estimating and mapping risk using environmental data. PLoS
Neglected Tropical Diseases, 6(5), e1669. Article available free online at:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3362644/
Moen, A.R., Wouda, W., Mul, M.F., Graat, E.A.M., and van Werven, T., “Increased risk of abortion following
Neospora caninum abortion outbreaks: a retrospective and prospective cohort study I four dairy herds,” Theriogenology
49 1301-1309 (1998)
Parashar, Umesh, et. al., “Case-control study of risk factors for human infection with a new zoonotic paramyxovirus,
nipah virus during a 1998 – 1999 outbreak of severe encephalitis in Malaysia,” The Journal of Infectious Diseases
181:1755-9 (2000)
Suwancharoen, D., Chaisakdanugull, Y., Thanapongtharm, W., and Yoshida, A., Serological Survey of
Leptospirosis in Livestock in Thailand, ´Epidemiol. Infect. (2013) 141, 2269-2277
References Available in the Resource Folder
Scurr, John H., Machin, Samuel J., Bailey-King, Sarah, Mackie, Ian J., McDonald, Sally, Smith, Philip D.
Coleridge, “Frequency and prevention of symptomless deep-vein thrombosis in ong-haul flights: a randomized trial,”
Lancet 357 (2001)
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Module: Epidemiology and Risk Analysis
Stirling, Andy C., and Scoones, Jan, “From risk assessment to knowledge mapping: science, precaution, and
participation in disease ecology,” Ecoogy and Society 12(2);14 (2009)
World Health Organization (WHO). 2005. Outbreak Communication Guidelines. Available online at
Institutional Repository for Information Sharing (IRIS), WHO:
http://apps.who.int/iris/handle/10665/69369.
References Available On-Line
Bonita, Ruth; Beaglehole, R; Kjellstrom, T. 2006. Basic epidemiology. World Health Organization, Geneva.
Available free online: http://apps.who.int/iris/handle/10665/43541.
European Environmental Agency. Introduction to Risk Assessment Concepts. Available freely online at
http://www.eea.europa.eu.
Food and Agriculture Organization of the United Nations (FAO). The Basics of Risk Assessment. Available
freely online at www.fao.org.
International Union for Conservation of Nature and the World Organization for Animal Health (IUCN
and OIE). 2014. Wildlife Disease Risk Analysis: Handbook of Procedures and Guidelines. Available online from
www.oie.int.
Office International des epizooties (OIE) 2010. Handbook on Import Risk Analysis for Animals and Animal
Products; Introduction and qualitative risk analysis.
Available online from www.oie.int.
National Research Council. Sustaining Global Surveillance and Response to Emerging Zoonotic Diseases.
Washington, DC: The National Academies Press, 2009. Available free online at www.nap.edu.
Ng V, Sargeant JM (2013) A Quantitative Approach to the Prioritization of Zoonotic Diseases in North America: A
Health Professionals’ Perspective. PLoS ONE 8(8): e72172. doi:10.1371/journal.pone.0072172. Available free
online at http://www.plosone.org.
U.S. General Accounting Office (GAO). West Nile Virus Outbreak – Lessons for Public Health Preparedness.
September 2000. GAO/HEHS-00-180. Available free online at
http://www.gao.gov/products/GAO/HEHS-00-180.
Veterinarians Without Borders. One Health for One World: A Compendium of Case Studies. Available free
online at http://www.onehealthinitiative.com.
World Bank. People, Pathogens and Our Planet. Volume 1: Towards a One Health Approach for Controlling Zoonotic
Diseases. Report no. 50833-GLB. 2010. Available online at: http://www.worldbank.org.
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