INTRO TO EPIDIMIOLOGY (PART 2) Flashcards
ECOLOGICAL ISSUES
FOCUS:
PUBLIC HEALTH
Degree of immunity necessary to eliminate a
disease from a population varies depending
on the type of infectious organism, the time
of year, and the density and social patterns of
the population
VACCINATION & PATTERNS
OF IMMUNITY
The cases double up in number per
susceptible host.
ABSENCE OF HERD IMMUNITY
The cases remain approximately
constant (50%).
○ If the percentage is greater than
50%, then the infection should
die out eventually.
PRESENCE OF 50% HERD IMMUNITY
DIPHTHERIA
○ Caused by bacteria:
Corynebacterium diphtheria
major epidemic
appeared in Russia despite
vaccination among individuals
DIPHTHERIA
Vaccine-produced
immunity decreases over time
PROBLEM OF DIPHTHERIA
additional
single vaccination for adults to
provide natural booster effect
RECOMMENDATION FOR DIPHTHERIA
Caused by virus: Variola
SMALLPOX
caused a more
severe skin eruption, but one
much less severe than
full-blown smallpox.
Variolation
Grinding of
scabs from patients with
a mild form and then
those who are
non-immune individuals
will blow their noses into
the scabs
PROCESS OF VARIOLATION
- generally caused
a single pustule at the site of
inoculation.
Vaccination
Vaccination Comes from _______ or cow
because epidemiologists
noted that milkmaids
develop less severe forms
of smallpox.
“vaca”
the dominant form of smallpox in
the 1970s. This was a relatively
mild form of smallpox that had a
low mortality rate.
Variola minor (alastrim)
This is a more
disfiguring and often fatal form
of the disease
Variola major (classical
smallpox
Smallpox vaccine is_________ for
both forms of smallpox
effective
Caused by the: Poliovirus
POLIOMYELITIS
POLIOMYELITIS Transmitted from
person-to-person through
________ route or by vehicle
(food)
fecal-oral
2 TYPES OF POLIOMYELITIS VACCINE
■ Inactivated or killed polio
vaccine (IPV) / Salk
■ Live, attenuated oral polio
vaccine (OPV) / Sabin
This became available in 1955.
Although it stimulated the production of blood
antibodies against the three types of
poliovirus, it did not produce cell-mediated
immunity in the intestine where the
polioviruses multiplied. So, it led to periodic
small epidemics of poliomyelitis in the late
1950s and early 1960s.
IPV
This was approved in the early
1960s. This produced cell-mediated
immunity, preventing the polio virus from
replicating in the intestine. It also provided
herd immunity. After the widespread use of
OPV, the prevalence of all three types of
poliovirus declined rapidly.
OPV
Caused by the spirochete
bacteria: Treponema pallidum
subspecies pallidum
SYPHILIS
usually
subsides spontaneously
PRIMARY STAGE OF SYPHILIS
a rash
or other lesions may
appear; also subside
spontaneously then a
a latent period follows after
SECONDARY STAGE OF SYPHILIS
Untreated infections may
provide some herd immunity
but does not protect individual
from progressive damage to
own body
TERTIARY STAGE OF SYPHILIS
Syphilis produces a highly infectious
a skin lesion is known as _______ – which is filled
with spirochete organisms.
chancre
primary killer of
children IN THE 19TH CENTURY
Diarrhea
eading cause of
adult mortality
in the 19th century
Tuberculosis
Sanitary Revolution:
○ Began in __________
England
Reduced infant mortality,
increased effective birth rate
Sanitary Revolution
a cause of today’s
worldwide population problem
Sanitary Revolution
Difference between birth rate
and death rate that develops
when a country undergoes
demographic transition
Demographic Gap
African
Sleeping Sickness Medical Term
Trypanosomiasis
Trypanosomiasis caused by parasites
of the species
___________ and is
transmitted by the
vector tsetse fly
Trypanosoma
brussay
has become a favorite habitat for breeding of snail hosts of both urinary and intestinal schistosomiasis
Nile River
Interaction or combination of
factors that produce a greater
effect than the sum of their
separate effects
SYNERGISM
A malnourished child has more difficulty
making antibodies and repairing tissue
damage which makes the child less resistant
to infectious diseases
SYNERGISM
A process by which 2 or more
strains of a virus combine to
form a new subtype of a virus
ANTIGENIC SHIFT
Accumulation of mutations
within virus genes over time
ANTIGENIC DRIFT
Widespread outbreak involving
multiple continents
GLOBAL PANDEMIC
a disease occurred in 1975 where it was spread by ticks
lyme disease
a disease ocurred in 1976 where that small infectious agent spreads via air-conditioning systems
Legionnaires’ disease
method of prevention for legionnaire’s disease
treat water in air-conditioning systems
disease that occurred in 1980 where staphylococcal toxin was associated with the use of tampons (especially Rely brand)
Toxic shock syndrom
a disease that occurred in 1981, where the viral agent spread via sexual activity, especially male homosexual activity, and via sharing of needles and exchange of blood and blood products during intravenous drug use and transfusions
Acquired Immunodeficiency Syndrom
in 1989 toxic contaminant associated with use of dietary supplements of L-tryptophan
Eosinophiliamyalgia syndrom
in 1993, hantavirus spread via contact with contaminated droppings of deer mice
Hantavirus pulmonary syndrome
in 1996, prions spread via ingestion of beef infected with bovine spongiform encephalopathy
New -variant Creutzfeldt-Jakob disease
animal coronavirus transferred to humans by handling and eating unusual food animals in 2003
Severe acute respiratory syndrome
Variation in the severity of
a disease process
The biologic spectrum of disease (Iceberg phenomenon)
Paramount to the field of
epidemiology
The biologic spectrum of disease
(Iceberg phenomenon)
Randomized trials of
preventive measures
Field Trials
Important phase of
evaluating a new vaccine
Field Trials
Studying the Biological Spectrum of
Disease
Biologic spectrum of disease
Surveillance of Community Health
Interventions
Field Trials
CONTRIBUTIONS OF EPIDEMIOLOGISTS
- Ongoing / Continued
Surveillance Programs - Syndromic Surveillance
Ensure a vaccine’s
continued safety and
effectiveness
○ Ongoing / Continued
Surveillance Programs
Epidemiologists
contributing to national
security
Epidemiologists
contributing to national
security
polio, measles,
smallpox
Ongoing / Continued
Surveillance Programs
Current recommendation
for measles vaccines:
initially at __ months of
ages, booster dose at 4-6
years old
15
Disease control priorities should be based not only on the currently existing size of the problem, but also on the potential of a disease to spread to others; its likelihood of causing death and disability; its cost to individuals, families, and the community
Setting Disease Control Priorities
Process of identifying the
nature and cause of a
disease
Diagnosis
Determined by methods
of clinical epidemiology
Effective treatment
Improved understanding
through epidemiology
Prognosis
Epidemiology forecasts
the probability and
impact of risks
Risk estimation
principles and methods of epidemiology are used in planning and evaluating medical health care
Improving Health Services Research
○ Epidemiologists can be called to
testify in court
○ Lawsuits may rely on
epidemiologic data
○ Expert medical testimony often
requires a high level of
epidemiological expertise
Providing Expert Testimony in Courts
of Law
■ Product hazards
■ Probable risks and side
effects of various
environmental exposures
and medications
Epidemiologists can be called to
testify in court
■ General environmental
exposures
■ Occupational illness
claims
■ Medical liability
■ Product liability
Lawsuits may rely on
epidemiologic data
CONTRIBUTIONS OF EPIDEMIOLOGISTS
● Investigating Epidemics and New
Diseases
● Studying the Biological Spectrum of
Disease
● Surveillance of Community Health
Interventions
● Setting Disease Control Priorities
● Improving Diagnosis, Treatment, and
Prognosis of Clinical Disease
● Improving Diagnosis, Treatment, and
Prognosis of Clinical Disease
● Improving Health Services Research
● Providing Expert Testimony in Courts
of Law
SYNERGISM OF FACTORS
PREDISPOSING TO DISEASE
● SYNERGISM
● ANTIGENIC SHIFT
● ANTIGENIC DRIFT
● GLOBAL PANDEMIC
DIFFERENT TYPES OF VACCINATIONS
- DIPHTHERIA
- SMALLPOX
- POLIOMYELITIS
- SYPHILIS
(1) VACCINATION & PATTERNS OF
IMMUNITY
A. ABSENCE OF HERD IMMUNITY
B. PRESENCE OF 50% HERD IMMUNITY
