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75 terms

Chapter 14

the scientific study of disease
the study of the cause of disease
the manner in which a disease develops
the invasion or colonization of the body by pathogenic microorganisms
occurs when an infection results in any change from a state of health
normal microbiota (normal flora)
microorganisms that live in the body and do not produce disease under normal conditions
transient microbiota
may be present in the body for several days, weeks, or months then disappear
microbial antagonism or competitive exclusion
normal microbiota benefit the host by preventing the overgrowth of harmful microorganisms
a type of symbiosis where one of the organisms benefits and the other is unaffected
a relationship between two organisms in which at least one organism is dependent on the other
a type of symbiosis that benefits both organisms
live microbial cultures applied to or ingested that are intended to exert a beneficial effect
a type of symbiosis where one organism benefits by deriving nutrients at the expense of the other organsim
opportunistic pathogens
microorganisms that ordinarily do not cause disease in their normal habitat in a healthy person, but may do so in a different environment (e. coli)
infectious diseases
diseases caused by microorganisms
Koch's postulates
used to determine the etiology of a disease
changes in body function that is felt by a patient as a result of disease
objective changes that can be observed and measured as a result of disease
a specific groups of signs or symptoms that always accompany a particular disease
communicable disease
any disease that spreads from one host to another either directly or indirectly
contagious disease
diseases that are easily spread from one person to another
noncommunicable disease
a disease that is not spread from one host to another
the number of people in a population who develop a disease during a particular time period
the number of people in a population who develop a disease at a specified time regardless of when it first appeared
sporadic disease
diseases that occur only occasionally in a pnopulatio
a disease constantly present in a population
many people in a given area acquire a certain disease in a relatively short period
an epidemic disease that occurs worldwide
acute disease
a disease that develops rapidly but lasts only a short time
chronic disease
a disease that develops more slowly and the body's reactions may be less severe, but it is likely to continue or recur for long periods
subacute disease
a disease that is intermediate between acute and chronic
latent disease
a disease in which the causative agent remains inactive for a time, but then becomes active to produce symptoms of the disease
herd immunity
when many immune people are present in a community
local infection
an infection in which the invading microorganisms are limited to a relatively small area of the body
systemic (generalized) infection
microorganisms or their products are spread throughout the body by the blood or lymph
focal infection
agents of a local infection enter a blood or lymphatic vessel and spread to other specific parts of the body where they are confined to specific areas of the body
a toxic inflammatory condition arising from the spread of microbes from a focus of infection
blood poisoning, a systematic infection arising from the multiplication of pathogens in the blood
the presence of bacteria in the blood
the presence of toxins in the blood
the presence of viruses in the blood
primary infection
an acute infection that causes initial illness
secondary infection
caused by an opportunistic pathogen after the primary infection has weakened the bodies defenses
subclinical (inapparent) infection
an infection that does not cause any noticeable illness
predisposing factor
makes the body more susceptible to a disease and may alter the course of the disease
incubation period
the interval between the initial infection and the first appearance of any signs or symptoms
prodromal period
a relatively short period that follows the period of incubation in some diseases, early mild symptoms
period of illness
the period the disease is most severe
period of decline
the period the signs and symptoms subside
period of convalescence
the period the person regains strength and the body returns to its prediseased state
reservoir of infection
a continual source of the disease organisms
people who are living reservoirs of infection who do not show signs or symptoms
diseases that occur primarily in wild and domestic animals and can be transmitted to humans
soil and water
two major nonliving reservoirs of infectious disease
contact transmission
the spread of an agent of disease by direct contact, indirect contact, or droplet transmission
direct contact transmission
the direct transmission of an agent by physical contact between its source and a susceptible host
indirect contact transmission
occurs when the agent of disease is transmitted from its reservoir to a susceptible host by means of a nonliving object
the general term for any nonliving object involved in the spread of an infection
droplet transmission
microbes are spread in droplet nuclei that travel only short distances
vehicle transmission
transmission of disease agents by a medium such as food, water, or air
animals that carry pathogens from one host to another
mechanical transmission
the passive transport of the pathogens on the insect's feet or other body parts
biological transmission
an active process of transmission through the blood, pathogen reproduces in the vector
nosocomial infection
infection that does not show any evidence of being present or incubating at the time of admission to a hospital; acquired as a result of a hospital stay
compromised host
host whos resistance to infection is impared by disease, therapy, or burns
emerging infectious diseases
diseases that are new or changing, showing increase in incidence in the recent past
the science that studies when and where diseases occur and how they are transmitted in populations
descriptive epidemiology
entails collecting all data that describe the occurrence of the disease under study
analytical epidemiology
analyzes a particular disease to determine its probable cause
experimental epidemiology
begins with a hypothesis about a particular disease and experiments to test the hypothesis
a branch of the U.S. Public Health Service located in Atlanta, GA.
the incidence of specific notifiable diseases
the number of deaths from specific diseases
morbidity rate
the number of people affected by a disease in a population in a given period of time
mortality rate
the number of deaths resulting from a disease in a population in a given period of time