Intro and Basic Concepts Flashcards
1
Q
what is epidemiology?
A
the study of the distribution, determinants, and deterrents of morbidity and mortality in the human population
2
Q
define morbidity
A
a departure from physical or mental well being
3
Q
what is public health?
A
the development, implementation, and analysis of policies designed to maintain or restore optimal population health
4
Q
what is distribution?
A
refers to the distribution of morbidity and mortality in a population
5
Q
what is needed to define distribution? (2)
A
- population must be defined
- description of frequency and patterns in terms of person, place, or time vairables
6
Q
what is distribution often considered?
A
the descriptive arm of epidemiology
7
Q
what do determinants tell?
A
why the morbidity or mortality is occurring, basically the cause of the disease state
8
Q
what are determinants often found by?
A
analytic or experimental epidemiological methods
9
Q
what do determinants assess?
A
risk factors associated with the affected populations
10
Q
describe how deterrants are used
A
utilizing the information gleaned from the collected fata, deterrents are mechanisms that can be put in place to reduce or eliminate the incidence and spread of disease
11
Q
do you have to understand the causes and distribution of a disease to use or determine deterrents?
A
nope; can be done in anbsence of understanding
12
Q
what is infectious epidemiology?
A
- a branch of science that deals with the incidence, distribution, and control of an infectious disease in a population
13
Q
what does infectious epidemiology determine?
A
the sum of factors controlling the presence or absence of a disease or a pathogen in a population
14
Q
what are the most complicated types of infectious diseases?
A
vector-borne
15
Q
what is a population?
A
a WELL-DEFINED group of individuals of a single species; defined by demographics, region, behavior, or other criteria
16
Q
what is a disease?
A
any physiologic state in a living organism that represents a departure from normal (homeostasis)
17
Q
what is the goal of infectious disease epidemiology?
A
controlling the presence (mitigate damage) or absence (keep it out) of a pathogen
18
Q
what is a disease agent?
A
causes the disease state
19
Q
describe the concept of shoe leather epidemiology
A
boots on the ground; get out there and collect your data
20
Q
what is symbiosis?
A
patterns of interaction among organisms
21
Q
what is parasitism?
A
one benefits at the cost of the other
22
Q
what is mutualism?
A
both benefit
23
Q
what is commensalism?
A
one benfits, the other mostly unaffected
24
Q
what is the basic premise of infectious disease epidemiology?
A
disease, illness, and ill health are not randomely distributed in a population, suggesting certain factors influence the presence and spread of disease
25
what are the 3 aspects of the epidemiologic triangle?
1. host: total of conditions favoring susceptibility
2. agent: total of virulence, abundance, etc.
3. environment: total of conditions favoring disease
26
what are vector borne disease?
disease spread by vectors (either living or mechanical) and maintained in zoonotic reservoir hosts that represent the most complex epidemiological problems
27
what is an infection?
entry and multiplication of an agent in the body of a person or animal
28
what are the 2 types of infections?
acute and chronic
29
relate acute and chronic infections
acute are caused by viruses and bacteria and will either resolve, become chronic, or host will die
30
what is disease?
noticeable impairment of body function; an abnormal condition usually with sign and symptoms and a specific causal agent is recognized
31
what is syndrome?
a collection of signs and symptoms that frequently appear together and characterize a particulr abnormality or condition but where the cause is USUALLY not known
32
describe infectious diseases (broadly)
all disease caused by microorganisms
33
describe communicable diseases (kind of synonymous with infectious diseases)
illness due to a specific infectious agent or its toxic products that results from transmission fron an infected person, animal , or inanimate reservoir to a susceptible host, either directly or indirectly
34
describe transmissible diseases
transmitted with difficulty usually by unnatural routes, like prions
35
what is ecology?
the totality or pattern of relations between organisms and their environment
36
what is etiology?
the cause of a disease (for infectious diseases: the infectious agent)
37
what is the natural history of a disease?
a description of the uninterrupted progression of a disease in an individual from the moment of exposure to causal agents until recovery or death
38
what is case synonymous with?
exposure
39
what is a primary case?
the person who brings the disease/infection into a population (can also be the index case but not always)
40
what are secondary cases?
persons who are infected by the primary case
41
what are generations of infections (waves)?
secondary cases are infected at about the same time and consequently considered tertiary cases
42
what is the index case?
the first case discovered in an outbreak (can be the primary case but not always)
43
what is reproductive rate? (Ro)
the potential of disease to spread in a population
44
what do the values of Ro (reproductive rate) mean?
Ro=1: every person infection infects 1 more person
Ro>1: every person infected infects more than one other person (ex measles Ro is 13-16)
Ro<1: disease headed toward eradication
45
what is the goal of epidemiology?
to get Ro<1
46
what is an opportunisitc infection/pathogen? give example
onlly cuases disease in hosts with impaired defense mechanisms or when introduced into an unusual location (ex. AIDS)
47
what are nosocomial infection? give example
result from treatment in a hospital or other healthcare service unit (ex. MRSA)
48
what is a pathogen?
an organism or virus capable of causing disease
49
what is virulence?
the degree of pathogenicity
50
how is virulence assessed?
in a clinical setting or in laboratory studies using experimental animals
51
what are the 3 modes of disease transmission?
1. direct
2. indirect
3. airborne
52
describe direct disease tranmission
immediate transfer of agent to receptive portal
53
give 4 examples of direct disease transmission
1. touching, biting, kissing, sexually
2. transplacental from mother to offspring
3. perinatally at time of delivery
4. direct projection of DROPLETS onto conjunctiva or mucous membranes during sneezing, coughing, etc. within 1 meter
54
describe vehicle-borne disease transmission
1. contaminated inanimate material or objects (fomites) such as toys, bedding, surgical instruments, or eating utensils
2. also includes food, water, and biological products such as blood, serum, tissue, or organs
55
what are vectors in the context of vector borne transmission?
typically an arthropod that picks up the pathogen from an infected person and transmits it to another
56
how do vectors transmit disease?
by bite, regurgitated blood, feces, or simple carriage
57
give 6 examples of vectors
1. lice
2. flies
3. mosquitoes
4. ticks
5. mites
6. fleas
58
what are the 2 types of vectors?
1. mechanical
2. biological
59
describe mechanical vectors
no replication of agent
60
describe bioligcal vectors
agent replicates and vector may be important part of agent life cycle
61
are vectors species specific?
some are, some aren't
62
what are bridge or zoonotic vectors?
move infectious agents from one host species to another
63
describe airborne disease transmission
dissemination of agents via aerosols, usually to the respiratory tract
64
how long and far can aerosols travel?
can remain suspended in air for a long period of time and not limited to the one meter range of droplets
65
describe infectivity of airborne agents
infectivity may persist for a long time, depending on the agent and environmental conditions
66
what are zoonoses?
infectious diseases transmissible under natrual conditions from vertebrate animals to humans, such as rabies and brucellosis
67
how are zoonoses different from veterinary diseases?
zoonoses go from animals to people and back and forth; veterinary diseases only affect animals
68
how are zoonoses most commonly transmitted?
vectorborne transmission most common
69
what is enzootic?
a disease continually present in animal community but in low numbers
70
what is epizootic?
when disease in animal population exceeds normal levels
71
what is a reservoir?
any person, animal, arthropod, soil, or substance in which an infectius agent normally lives and multiplies in such a manner that it can be transmitted to a susceptible host
72
describe the chain of transmission
a circle but starting at agent
agent follows mode of transmission to portal of entry to the susceptible host, then person to person transmission occurs and a reservoir is infected, the agent then leaves the portal of exit of the reservoir and cycle starts over
73
what are the 3 possible outcomes of exposure to an infectious agent?
1. no infection
2. symptomatic infection
3. asymptomatic infection
74
what are the 4 possible results of a symptomatic infection?
1. death
2. immunity
3. carriage (reservoir)
4. recovery
75
what are the 3 possible outcomes of an asymptomatic infection?
1. carriage (reservoir)
2. recovery, no immunity
3. immunity
76
what happens to those who develop immunity from an infectious agent?
no longer susceptible
77
what happens to those who recover without immunity from an infectious agent?
back to the susceptible pool
78
what are 6 factos that affect the agent in the triangle of disease transmission?
1. infectivity
2. pathogenicity
3. virulence
4. immunogenicity
5. antigenic stability
6. survival
79
what are 6 factors affecting the host in the triangle of disease transmission?
1. age
2. sex
3. genotype
4. behavior
5. nutritional status
6. health status
80
what are 6 factors affecting the environment in the triangle of disease transmission?
1. weather
2. housing
3. geography
4. occupational status
5. air quality
6. food
81
what is endemic?
the constant presence of a disease or infectious agent within a given geographic area (may be at high or low levels)
82
what is epidemic?
the occurrence in a community or region of cases of an illness (or outbreak) with a frequency clearly in excess of normal expectancy
83
what is pandemic?
generally considered an epidemic occurring over a wide geographic area, usually crossing country or continental borders
84
what is incubation period?
the time from inital contact with infectious agent and the first appearance of symptoms (variable)
85
what is the latent period?
the time from inital infection until person becomes infectious for others
86
what is the infectious period?
the time period when a person can transmit a disease (period of comminucability)
87
can a person be infectious before symptoms develop?
yes and can also remain infectious when symptoms fade
88
what is the serial interval (generation time)
the time for diseases to spread from person to person, the time period between successive generations of cases
89
what is a carrier?
a person or animal that harbors a specific infectious agent without discernible clinical disease and serves as a potential source of infection
90
what is attack rate?
the proportion of susceptible individual exposed to an infectious agent who become clinically ill
91
what is the case fatality rate?
the number of people who die divided by the number of people infected
92
what is the incidence (rate)?
the number of new cases of a specified disease diagnosed or reported during a defined time divided by the number of persons within that population
93
what is prevalence?
the total number of persons sick with a certain condition in a stated population and a particular time (point prevalence) or during a stated period of time (period prevalence)
94
what is morbidity rate?
all the persons in the population under consideration who become CLINICALLY ILL during the state time period
95
what is the morbidity rate usually related to?
the incidence rate within a sub-population
96
what is the mortality rate?
the number of deaths within a population during the stated time period
97
what is public health?
the approach to medicine that is concerned with the health of the community as a whole
98
list and describe the 3 core public health functions
1. assessment: monitoring of the public's health to identify problems and priorities
2. policy development: to solve problems and address priorities
3. assurance: that capabilities are there to address problems and priorities
