MIDTERMS: EPIDEMIOLOGY Flashcards
the word epidemiology comes from the Greek words
EPI- on or upon
DEMOS- people
LOGOS- study of
the distribution and determinants of health- related states or events in specified populations, and the application of this study to the control of health problems
Epidemiology
Study of ecology of health and disease, and the application of knowledge gained to promote health and control diseases.
Epidemiology
Study of interrelationship of factors in particular areas in the field of health, and the application of the results of such studies to influence such factors to achieve a given outcome
Epidemiology
traditional epidemiologic triad model holds that infectious diseases result from the interaction of agent, host, and environment.
chain of infection
T or F
Transmission occurs when the agent leaves its reservoir or host through a portal of exit, is conveyed by some mode of transmission, and enters through an appropriate portal of entry to infect a susceptible host.
True
Any element, substance, or force whether living or non-living, the presence or absence which can initiate or perpetuate a disease process.
Agent
Could be physical and mechanical in nature
} Chemicals
} Exogenous
} Endogenous
Agent
Physical features, biologic requirements, chemical make-up, viability, and resistance.
Inherent Characteristics
measures the ability of an agent when lodged in the body to set-up a specific reaction, local or general, clinical or sub-trial.
Pathogenicity
refers to the severity of the reaction produced and is usually measured in terms of fatality.
Virulence
the ability to stimulate the host to produce antibodies
Antigenicity
Refers to the reservoir and sources of infection and modes of transmission.
Characteristics in relation to the environment
habitat in which the agent normally lives, grows, and multiplies.
reservoir
Includes humans, animals and the environment
reservoir
T or F
The reservoir may or may not be the source from which an agent is transferred to a host.
True
Many common infectious diseases have human
reservoirs.
human reservoirs
sexually transmitted diseases, measles, mumps, streptococcal infection, and many respiratory pathogens
human reservoirs
Many of these diseases are transmitted from animal
to animal, with humans as incidental hosts.
animal reservoir
refers to an infectious disease that is transmissible under natural conditions from vertebrate animals to humans
Zoonosis
Plants, soil, and water in the environment are also
reservoirs for some infectious agents
Environmental reservoir
Many fungal agents, such as those that cause histoplasmosis, live and multiply in the soil.
Environmental reservoir
the path by which a pathogen leaves its host.
portal of exit
usually corresponds to the site where the pathogen is localized.
portal of exit
occurs through skin- to-skin contact, kissing, and sexual intercourse.
direct contact
T or F
Direct contact also refers to contact with soil or vegetation harboring infectious organisms
True
refers to spray with relatively large, short-range aerosols produced by sneezing, coughing, or even talking.
droplet spread
T or F
Droplet spread is classified as direct because transmission is by direct spray over a few feet, before the droplets fall to the ground
True
refers to the transfer of an infectious agent from a reservoir to a host by suspended air particles, inanimate objects (vehicles), or animate intermediaries (vectors)
indirect transmission
occurs when infectious agents are carried by dust or droplet nuclei suspended in air.
airborne transmission
T or F
Airborne dust includes material that has settled on surfaces and become resuspended by air currents as well as infectious particles blown from the soil by the wind.
True
may indirectly transmit an infectious agent include food, water, biologic products (blood), and fomites (inanimate objects such as handkerchiefs, bedding, or surgical scalpels).
vehicle borne
T or F
Vector-borne such as mosquitoes, fleas, and ticks may carry an infectious agent through purely mechanical means or may support growth or changes in the agent.
True
refers to the manner in which a pathogen enters a susceptible host
portal of entry
T or F
The portal of entry must provide access to tissues in which the pathogen can multiply or a toxin can act.
True
final link in the chain of infection is a susceptible host.
host
T or F
Susceptibility of a host depends on genetic or constitutional factors, specific immunity, and nonspecific factors that affect an individual’s ability to resist infection or to limit pathogenicity.
True
T or F
An individual’s genetic makeup may either increase or decrease susceptibility.
True
Interventions are directed at?
Controlling or eliminating agent at
source of transmission
Protecting portals of entry
Increasing host’s defenses
