Title: Introduction to Epidemiological Methods
1Introduction to Epidemiological Methods
- Bioterrorism Epidemiology
- Module 4
- Missouri Department of Health
- And Senior Services
2Learning Objectives
- Define bioterrorism epidemiology
- Describe epidemiological approach to
understanding disease etiology - Recognize difference between incidence and
prevalence - Distinguish between the stages of the disease
process
3Biological and Chemical Epidemiology
- The study of the distribution and determinants of
diseases resulting from a biological or chemical
attack
4Sources of Epidemiologic Clues to a Disease
Outbreak
- Clinicians office or medical clinic
- Emergency room
- Laboratory
- Veterinary Clinic
- Pharmacy
5Epidemiologic Approach to Understanding Disease
Etiology
- Descriptive epidemiology - identifying
associations of disease in relation to - Time
- Place
- Persons
6Epidemiologic Approach to Understanding Disease
Etiology
- Analytic epidemiology
- Identify associations of disease with possible
etiologic factors (chemical release, biological
agent) - Further refine and test hypotheses regarding
etiology
7Problems Investigating the Causes of Disease
- Specific agent might not be known
- Location of agent release might not be known
- Signs and symptoms might not differentiate
disease - More than one agent might be used
- Time of agent release might not be known
- Latency period might not be known
- Latency is not the same for all people
8Epidemiologic Triad of Disease
Host
Environment
Agent
9Epidemiologic Triad of Disease
Host
Environment
Agent
10Epidemiologic Triad of Disease
Host
Environment
Agent
11Epidemiologic Triad of Disease
Host
Environment
Agent
12Modes of Transmission
- Direct
- Contact
- Droplets
- Indirect
- Airborne
- Vehicle-borne
- Vector-borne
- Mechanical
- Biologic
Host
Environment
Agent
13Modes of Transmission
- Direct
- Contact
- Droplets
- Indirect
- Airborne
- Vehicle-borne
- Vector-borne
Host
Environment
Agent
14Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Temperature Humidity Altitude Wind Crowding
15Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Temperature Humidity Altitude Wind Crowding
16Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Location of Release Temperature Humidity Altitude Wind Crowding
17Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Location of Release Temperature Humidity Altitude Wind Crowding
18Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Location of Release Temperature Humidity Altitude Wind Crowding
19Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Location of Release Temperature Humidity Altitude Wind Crowding
20Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Location of Release Temperature Humidity Altitude Wind Crowding
21Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Location of Release Temperature Humidity Altitude Wind Crowding
22Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Location of Release Temperature Humidity Altitude Wind Crowding
23Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Location of Release Temperature Humidity Altitude Wind Crowding
24Factors That May Be Associated With Disease
Host Characteristics Types of Agents and Examples Environmental Factors
Age Sex Race Religion Customs Occupation Genetic profile Marital status Immune status Vaccination status Biologic (bacteria, viruses, toxin) Chemical (nerve, blister) Nuclear Bombs and flammables Location of Release Temperature Humidity Altitude Wind Crowding
25Numerators and Denominators
26What Is a Numerator
27What Is a Numerator
- Count of cases
- Frequently organized in a line-listing
28Line Listing
29What Is a Numerator
- Count of cases
- Frequently organized in a line-listing
- Allows for regrouping and counting cases by their
various characteristics
30What Is a Numerator
- Count of cases
- Frequently organized in a line-listing
- Allows for regrouping and counting cases by their
various characteristics - Might be incident or prevalence cases
31Incidence and Prevalence
Incidence
32Incidence and Prevalence
Number of new cases of a disease over a period of
time
Incidence
33Incidence and Prevalence
Prevalence
34Incidence and Prevalence
Total number of cases of a disease
Prevalence
35Relationship Between Incidence and Prevalence
Recovery
Death
Incidence
Prevalence Pot
36Relationship Between Incidence and Prevalence
Recovery
Death
Incidence
Prevalence Pot
37Relationship Between Incidence and Prevalence
Recovery
Death
Incidence
Prevalence Pot
38Relationship Between Incidence and Prevalence
Recovery
Death
Incidence
Prevalence Pot
39Relationship Between Incidence and Prevalence
Recovery
Death
Incidence
Prevalence Pot
40Relationship Between Incidence and Prevalence
Recovery
Death
Incidence
Prevalence Pot
41Relationship Between Incidence and Prevalence
Recovery
Death
Incidence
Prevalence Pot
42Relationship Between Incidence and Prevalence
Recovery
Death
Incidence
Prevalence Pot
43Relationship Between Incidence and Prevalence
Recovery
Death
Incidence
Prevalence Pot
44Relationship Between Incidence and Prevalence
- Under the assumption of a steady-state
- Prevalence I D
- I incidence
- D duration
Recovery
Death
Incidence
Prevalence Pot
45Relationship Between Incidence and Prevalence
- Under the assumption of a steady-state
- Prevalence I D
- I incidence
- D duration
Recovery
Death
Incidence
Prevalence Pot
46Relationship Between Incidence and Prevalence
- Under the assumption of a steady-state
- Prevalence I D
- I incidence
- D duration
Recovery
Death
Incidence
Prevalence Pot
47Episodes of Tularemia
Number of Persons
M
L
K
J
I
H
G
F
D
E
C
B
A
TIME
48Episodes of Tularemia
Number of Persons
M
L
K
J
I
H
G
F
D
E
C
B
A
TIME
49Episodes of Tularemia
Number of Persons
M
L
K
J
I
H
G
F
D
E
C
B
A
TIME
50Episodes of Tularemia
Number of Persons
M
L
K
J
I
H
G
F
D
E
C
B
A
TIME
51Episodes of Tularemia
Number of Persons
M
L
K
J
I
H
G
F
D
E
C
B
A
TIME
52Episodes of Tularemia
Number of Persons
M
L
K
J
I
H
G
F
D
E
C
B
A
TIME
53Episodes of Tularemia
Number of Persons
M
L
K
J
I
H
G
F
D
E
C
B
A
TIME
54What is the prevalence of tularemia on July 1998
in these 20 people?
Number of Persons
M
L
K
J
I
H
G
F
D
E
C
B
A
TIME
55What is the prevalence of tularemia on July 1998
in these 20 people?
Number of Persons
M
L
K
J
I
H
G
F
D
E
C
B
A
TIME
56The Natural History of Disease
Outcome Cure Control Disability Death
Healthy
Disease Symptoms Seek Diagnosis
Treatment Onset Care
57The Natural History of Disease
Outcome Cure Control Disability Death
Healthy
Disease Symptoms Seek Diagnosis
Treatment Onset Care
58The Natural History of Disease
Outcome Cure Control Disability Death
Healthy
Disease Symptoms Seek Diagnosis
Treatment Onset Care
59The Natural History of Disease
Outcome Cure Control Disability Death
Healthy
Disease Symptoms Seek Diagnosis
Treatment Onset Care
60The Natural History of Disease
Outcome Cure Control Disability Death
Healthy
Disease Symptoms Seek Diagnosis
Treatment Onset Care
61The Natural History of Disease
Outcome Cure Control Disability Death
Healthy
Disease Symptoms Seek Diagnosis
Treatment Onset Care