CH. 14 Principles of Epidemiology Flashcards
Pathology
study of how a disease develops.
Etiology
the study of a cause of a disease.
Pathogenisis
manner in which a disease develops.
Infection
an invasion by a pathogenic organism.
Disease
disruption in homeostasis.
Define: Normal Microbiota (flora)
-What was the first exposure?
established in and on the body but do not cause diseases under normal circumstances.
-in utero (non normal flora state)
Normal Microbiota (flora)
1st Exposure:
2nd Exposure:
3rd Exposure:
1st: Birth
2nd: First breath
3rd: First Meal
What is Microbial Antagonism?
normal flora prevents the growth of harmful or unwanted bacteria.
Relationships to Host (RtH)
Symbiosis:
refers to relationship between normal flora and the host.
(RtH)
Commensalism:
one organism benefits, the other is unaffected.
(RtH)
Mutualism:
both organisms benefit
(RtH)
Parasitism:
one benefits the other is harmed.
(RtH)
Opportunistic Pathogens:
does not cause a disease in its area of the body, but will under the right circumstances.
Etiology
What is Koch’s Postulates?
- Same pathogen must be present in every case of disease.
- Pathogen must be isolated from the host and grown in pure culture.
- Pathogen from the pure culture must be inoculated into a healthy specimen.
- Pathogen must be isolated from the specimen and identified as the original organism.
*Exceptions: Syphilis, Leprosy, and viral agents will not replicate artificial media, must be grown in cells.
Symptoms:
are subjective and can only be felt by patient.
ex. pain
Signs:
Objective and can be measured.
ex. take temperature
Syndrome:
of a disease are all signs and symptoms
Communicable Disease:
disease that spreads from host to host either directly or indirectly.
Contagious Disease:
disease that spreads easily.
Non-communicable Disease:
do not spread between host must be introduced.
Incidence:
&
Prevelance:
-refers to the # of people in a population that develop a disease in a given length of time.
(Spread of a disease)
-refers to the # of people who develop a disease regardless of time frame.
(both old and new cases) (how long was disease in population)
Sporadic:
Endemic Disease:
Epidemic Disease:
Pandemic:
Sporadic: a disease that occurs occasionally.
Endemic: constantly present in a population.
Epidemic: many people in an area develop a disease in a short period of time.
Pandemic: a world wide epidemic.
Acute:
Chronic:
Latent:
*Herd Immunity:
Acute: comes fast, short lived. (flu)
Chronic: develops slowly and are long lasting.
Latent: lays dormant in your body.
Herd Immunity: an increase in the # of immune people in a community. Vaccinations.
Local Infection:
Systemic Infection:
Focal Infection:
- Microbes are limited to a specific area. (puss)
- Spread throughout entire body. (measles)
- Local infection that has spread and settled in an another place in body.
Bacteremia:
Septicemia:
Viremia:
- bacteria in the blood
- microbes multiply in the blood
- viruses in blood
Primary infection:
Secondary Infection:
*Predisposing Factors:
- what caused your illness
- caused by opportunistic pathogen
-factor that makes someone more susceptible
gender; age; climate; nutrition
Development of Disease 1. 2. 3. 4. 5.
- Incubation Period: time from exposure and the first signs and symptoms.
- Prodromal Period: mild symptoms for a short period of time.
- Illness: signs and symptoms are evident
- Decline: signs and symptoms are lessened. however, volnuerable to secondary infection.
- Convalescence: body regains strength.
Spread of Infection
Reservoirs:
Living Reservoirs:
Non living:
-living or inanimate object that provides a pathogen with adequate living conditions.
-humans
Carrier: without signs or symptoms.
Animals: Zoonoses- transferred to humans
- Soil: fungi
water: fecae
