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86 Cards in this Set
- Front
- Back
define infection
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pathogenic microorganisms penetrate the host defenses, enter the tissues, and multiply
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define pathologic
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state that results when the infection damages or disrupts tissues and organs- disease
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define infectious disease
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the disruption of a tissue or organ caused by microbes or their products
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define metagenomics
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Metagenomics being used to identify the microbial profile inside and on humans
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name some sites that harbor a knwn normal biota
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skin and mucous membranes
upper respiratory tract g.i. tract, vagina outer urethra, external genitalia external ear canal external eye |
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what are some microbe free/sterile anatomical sites
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heart
liver kidneys and bladder lungs, brain, spinal cord muscles, bones, ovaries, testes, internal eye Blood, urine, cs fluid, semen, amniotic fluid |
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describe microbial antagonism
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bacterial biota benefit the human host by preventing the overgrowth of harmful microorganisms
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define endogenous infections
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caused by biota that are already present in the body
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define pathogen
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a microbe whose relationship with its host is parasitic and results in infection and disease
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define pathogenicity
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how nasty is this critter?
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what is an opportunistic pathogens
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usually is already present in the body but arises because the immune system is comprimised
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what are some factors that weaken host defenses and increase susceptibility to infection?
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old age and extreme youth
genetic defects and acquire defects in immunity surgery, chemotherapy, immunosuppressive drugs, stress, other infections |
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**
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**
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define virulence
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the degree of pathogenicity
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what is virulence determined by?
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Determined by its ability to
Establish itself in the host Cause damage |
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define virulence factor
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any characteristic or structure of the microbe that contributes to its virulence
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What are the steps to a microbe becoming established in our bodies?
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1. Microbe enters the tissues of the body by a portal of entry
2. Adhesion - attaching to the host 3. Surviving host defenses |
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infectious agents are either sourced _____ or ______
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exogenously or
endogenously |
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name 4 portals of entry
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skin
GI tract respiratory tract urogenital tracts |
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which portal of entry allows the greatest number of pathogens
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respiratory tract
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why can some std's penetrate unbroken surfaces
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more permeable tissues in the urogenital tract
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For most agents, infection only proceeds if the _____ _____ is present
Microorganisms with smaller IDs have ______ ______ |
infectious dose (ID)
greater virulence |
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what are the 3 ways that adhesion occurs
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fibriae
capsules spikes |
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whar are some ways that a micro-org can survive host defenses?
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antiphagocytic factors:
leukocidins - toxic to wbc's extracellular surface layer making diff for phago to engult some can survive inside phago's. |
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how could you survive a phagocytic attack if you were a pathogen?
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have a durable capsule
have longer polysaccharides that string out, making it difficult for the phagocyte to engulf produce leukocidins to kill wbc's |
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how do virulence factors contribute to tissue damage?
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1. exoenzymes secreted by bacteria degrade bonds between host cells
2. exo toxins break down host cells themselves 3. stimulate too much inflammatory response |
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toxigenicity
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the power to produce toxins
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toxinoses
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a variety of diseases caused by toxigenicity
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toxemias
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toxinoses in which the toxin is spread by the blood from the site of infection (tetanus and diphtheria)
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intoxications
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toxinoses caused by ingestion of toxins (botulism)
toxin causes the reaction, not the organism |
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exotoxins
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toxins pushed/secreted out of active cells
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endotoxins
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present in the cell, released from micro-org when cell is lysed.
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necrosis
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accumulated damage leads to cell and tissue death
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infection stays in one place - called ______
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localized infection
i.e. boil |
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infection spreads everywhere in the body - called _______
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systemic infection
i.e. |
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infection develops in one area and then another infection caused by the same organism develops in a different area
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Focal infections
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infection caused by various microbes
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mixed infection
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infections caused in two separate areas by two separate organisms
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primary and secondary infection
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define "sign"
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Sign: any objective evidence of disease as noted by an observer
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define "symptom"
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Symptom: the subjective evidence of disease as sensed by the patient
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define syndrome
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Syndrome: when a disease can be identified or defined by a certain complex of signs and symptoms
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signs and symptoms of inflammation
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Fever, pain, soreness, swelling
Edema Granulomas and abscesses Lymphadenitis Lesion: the site of infection or disease |
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edema
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fluid build up
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lymphadenitis
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lymph fluid build up
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name some sign of infection in the blood
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Changes in the number of circulating white blood cells
leukocytosis leukopenia septicemia bacteremia or viremia |
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define leukocytosis
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increased wbc count
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define leukopenia
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decreased wbc count
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define septicemia
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Septicemia: general state in which microorganisms are multiplying in the blood and are present in large numbers
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define bacteremia or viremia
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Bacteremia or viremia: microbes are present in the blood but are not necessarily multiplying
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subclinical
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asymptomatic, inapparent infections
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portals of exit for micro orgs to vacate the host
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coughing/sneezing
skin cells insect bites blood, urine, feces |
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latency
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a dormant state
The microbe can periodically become active and produce a recurrent disease |
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Long-term or permanent damage to tissues or organs is called:
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sequelae
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define reservoir
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Reservoir: the primary habitat in the natural world from which a pathogen originates
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define source
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Source: the individual or object from which an infection is actually acquired
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define carrier
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an individual who inconspicuously shelters a pathogen and spreads ith to others without any notice
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what are the different types of carriers?
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Asymptomatic carriers
Incubation carriers Convalescent carriers Chronic carrier Passive carrier |
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define vector
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a live animal that transmits an infectious agent from one host to another
Majority are arthropods Larger animals can also be vectors |
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what actively participates in a pathogen's life cycle
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biological vector
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what transports the infectious agent without being infected
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mechanical vectors
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define zoonosis
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Zoonosis: an infection indigenous to animals but naturally transmissible to humans
Human does not contribute to the persistence of the microbe Can have multihost inovvlement At least 150 worldwide |
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what is a passive carrier?
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not infected, just unknowingly picks up a pathogen and passes it to someone else.
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what is the best nonliving reservoir?
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water
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what are some other nonliving reservoirs?
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soil,
water, air |
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define communicable disease
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Communicable disease: when an infected host can transmit the infectious agent to another host and establish infection in that host
Transmission can be direct or indirect Contagious agent: highly communicable |
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describe noncommunicable diesase
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does not arise through transmission of the infectious agent from host to host
Acquired through some other, special circumstance Compromised person invaded by his or her own microbiota Individual has accidental contact with a microbe in a nonliving reservoir |
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define fomite
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inanimate object / vehicle
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what are the two types of transmission
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contact transmission
indirect transmission |
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what are some examples of indirect transmission
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food, water, biological products, fomites
contaminated objects - food poisoning, oral-fecal air - droplet nuclei, aerosols |
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define nosocomial infection
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Nosocomial infections: infectious diseases that are acquired or develop during a hospital stay
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what are the most common nosocomial infections?
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urinary tract infections
then, surgical sites then respiratory |
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describe universal precautions
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guidelines from the Centers for Disease Control and Prevention
Assume that all patient specimens could harbor infectious agents Include body substance isolation (BSI)techniques to be used in known cases of infection |
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what is the causative agent called?
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etiologic agent
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what is the first step of Koch's postulates?
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Find evidence of a particular microbe in every case of a disease
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what is the second step of Koch's postulates?
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Isolate that microbe from an infected subject and cultivate it in pure culture in the laboratory
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what is the third step of Koch's postulates?
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Inoculate a susceptible healthy subject with the laboratory isolate and observe the same resultant disease
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what is the fourth step of Koch's postulates?
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Reisolate the agent from this subject
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define epidemiology
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Epidemiology: the study of the frequency and distribution of disease and other health-related factors in defined human populations
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define prevalence
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Prevalence: the total number of existing cases with respect to the entire population
Prevalence = (total number of cases in population / total number of persons in population) x 100 = % |
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define incidence
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Incidence: the number of new cases over a certain time period
Incidence = number of new cases / total number of susceptible persons |
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define mortality rate
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Mortality rate: the total number of deaths in a population due to a certain disease
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define morbibity rate
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Morbidity rate: the number of persons afflicted with infectious diseases
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endemic occurrence
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focused in a specific region (of a country) i.e. hanta virus
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epidemic occurrence
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widespread occurrence spread between communities
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sporadic occurrence
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pops up out of nowhere
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pandemic occurrence
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widespread occurance between continents
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