MICRO FINAL! Flashcards
(77 cards)
1
Q
infection
A
colonization or invasion of the body by pathogens
2
Q
disease
A
infection that results in any change from a normal state of health
3
Q
etiology or etiology agent
A
cause of an infectious disease
4
Q
pathogenesis
A
manner in which a disease develops in the host
5
Q
primary (true) pathogen
A
causes disease in healthy individuals with normal immune defenses
6
Q
secondary (opportunistic) pathogen
A
cause disease in immunocompromised individuals or when displaced
7
Q
Two types of secondary pathogens?
A
- saprophytes in the environment
2. one’s own normal flora
8
Q
normal flora also known as?
A
indigenous flora, normal microbiota, resident flora
9
Q
the human body begins to be colonized by normal flora?
A
during and immediately after birth
10
Q
local infection
A
microbes, its enzymes or toxins confined to a particular body site(target tissue)
11
Q
focal infection
A
microbes disseminate from focus of infection, but target a specific body site
12
Q
systemic infection
A
microbes or toxins disseminate throughout the body to several sites/organs via blood/lymph
13
Q
synergism or mixed infection
A
microbes work together to digest host target tissue
14
Q
asymptomatic
A
infection that produces no noticeable symptoms, but microbes are active and host acts as carrier
15
Q
primary infection
A
acute infection that causes initial illness
16
Q
acute infection
A
infection that has rapid onset and is short lived
17
Q
secondary infection
A
opportunistic infection that occurs during or following another already existing primary infection
18
Q
chronic infection
A
infection develops slowly, body reaction is less severe but disease is continual or recurrent for long periods
19
Q
subacute infection
A
infection that is intermediate between an acute and a chronic infection
20
Q
latent
A
infection in which microbes remain dormant in tissues for years without symptoms, but are periodically reactivated
21
Q
nosocomial infection
A
infectious disease acquired through a stay in the hospital or other health care facility
22
Q
teratogenic
A
birth defects caused by infectious agent or other agents(smoke,alcohol) that cross the placenta
23
Q
sequela
A
a condition, pathologic effect such as arthritis as a consequence of an infectious disease
24
Q
incubation period
A
time interval between initial contact with pathogen and 1st signs and symptoms of disease(1 or 2 weeks)
25
prodromal period
short period following incubation period in which symptoms are mild.
ex: aches, fatigue,koplik spots
26
period of illness
stage when disease is acute and patient exhibits signs and symptoms
ex. fever,chills,gi disturbances, myalgia
27
period of decline
signs and symptoms of the disease subside, lasts 1 to several days and patient is vulnerable to secondary infection
28
period of convalesence
period of recovery when patient regains his strength and body returns to a healthy state
29
signs
objective and measurable, noticed by observer
| ex: fever, rash, increase WBC, decrease antibodies
30
symptoms
subjective, felt by patient
| -ex: aches, pain, nausea, fatigue
31
reservoir
a host or environment that supports the survival, multiplication and spread of pathogens
*reservoir and host are not always the same. for example HAV reservoir is "humans" but its source is "food"
32
Reservoirs of infectious agents
1. Humans
2. Animals
3. Environment
33
Humans
act as active or passive carriers to transmit infectious agents human to human directly or indirectly.
- types of human carriers: asymptomatic, incubating, convalescent, chronic or latent carriers.
- how humans can act as passive carriers: bed pans and eating utensils
34
Animals
large animals or arthropod/insect/zoonotic infection transmit pathogen animal to human
- biological vector: animals that actively participate in pathogens life cycle
ex: mosquito-malaria
- mechanical vector: animals body part transmits pathogens to human thru food or other means
ex. bacillary dysentery
35
Environment
-vehicles/contaminated materials such as air, water,soil,food,fomites,media, blood etc..
36
fomite
any contaminated object
| ex. door knob,penny,syringe,towel
37
communicable disease
microbial disease spread from one host to another via direct or indirect contact
38
non-communicable disease
microbial disease NOT spread from one host to another
39
means of direct contact transmission
1. horizontal
2. vertical
3. biological vector
4. droplet
40
horizontal
transmission occurs when one host physically contacts another host via touching, kissing, sex
41
vertical
transmission is when an infectious agent is transmitted from parent to offspring via placenta or breast milk
42
biological vector transmission
arthropod
| ex: mosquito bites infected host and transmits agents to another host
43
droplet tranmission
one host sprays respiratory secretions(mucus, saliva, sputum) on another host
44
indirect contact transmission
1. fomite
2. food borne
3. water borne
4. other media
5. droplet nuclei
6. aerosol
45
fomite transmission
an infected host contaminated an object
| ex: doorknob=uninfected host touches it
46
food borne transmission
food such as custard, contaminated with feces or urine is eaten
47
water-borne transmission
infectious agent in water
| ex. cholera is deposited w/ feces and ingested
48
other media transmission
examples: iv fluid, blood,serum,milk
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droplet nuclei transmission( a type of air borne transmission)
-contaminated fine moisture droplets or dust particles that remain suspended in indoor air for long periods
50
epidemiology
the study of frequency and spread of disease in a defined community or population
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prevalence
refers to the number of old or new cases(% of a population) having a disease over a given time period
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incidence
refers to the number of new cases contracting a disease over specific period of time
53
epidemic
a disease introduced from the outside that affects a large number of people in a community simultaneously, many exhibit symptoms
ex: tuberculosis
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endemic
a disease prevailing continuously in a community, few exhibit symptoms
ex: common cold
55
pandemic
a disease that spreads across continents
| -worldwide ex: AIDS
56
sporadic
a disease in which a few isolated cases occur in widespread locations
-ex: tetanus in US
57
portal of entry
routes through which pathogens/microbes enter the body skin or mucous membranes
58
various portals of entry
1. resp route
2. fecal oral route
3. tranplacental route
4. intact skin
5. genitourinary route
6. parenteral route
59
resp route
contaminated moisture droplets or dust particles are inhaled through the rest. route.
ex. =measles
60
fecal-oral route
food or water contaminated w/ feces or urine is ingested through the fecal-oral route
ex. cholera, HAV
61
transplacental route
infectious agents are transmitted from mother to infant through the placenta or birth canal via tranplacental route
ex: rubella, HIV, toxoplasmosis, syphillis
62
intact skin
microbes gain direct access to sterile tissues beneath the skin through hair follicles of sweat glands via the intact skin route.
-ex staphylococcal skin infections such as fununcles
63
genitourinary route
sexual contact allows microbes to enter the body through the genitourinary route
ex: HIV, HBV, HPV
64
parenteral route
microbes gain direct accèss to tissue beneath the skin or MMs through an injury or wound
ex: impetigo, cellulitis
65
STORCH
an acronym that represents the most common transplacental infections of the fetus and neonate
66
virulence
the degree of pathogenicity or the ability of the microbe to invade that host and or produce toxins
67
virulence factors
properties possessed by microbe(esp bacteria) that allow it to attach, invade and evade host barriers to disease
68
4 main categories of virulence factors:
1. numbers of invading microbes or amount of toxin
2. surface components on microbes
3. exoenzyme
4. toxin
69
numbers of invading microbes or amount of toxin
- lethal dose 50(LD50)=minimum amount of toxin to cause death in at least 50% of inoculated lab animals or a human population
- infectious dose 50(ID50)= minimum number of microbes to cause death in at least 50% of inoculated lab animals or a human population
- the lower the number of invading microbes or dose of toxin, the greater the virulence of the microbe
70
surface components on microbes
- allow microbes to attach and enter host cells or evade host defenses such as phagocytes(macrophages, neutrophils), cytotoxic T cells, antibodies, NK cells or complement
- bacterial capsule, fimbriae, flagella, or cell wall M protein
- protozoan=flagella or cillia
- Helminth=hooks or suckers
- viral spikes
- abscesses(staph) or granulomas(TB)
71
Exoenzyme
- enzyme/protein products produced inside bacterial cells and released to outside body fluids
1. coagulase: cause fibrin to clot(coagulates blood plasma)
2. kinase: breaks down fibrin clots(aid in spread of bacteria)
3. Hyaluronidase: breaks down Hyaluronic acid in CT
4. Collagenase: breaks down collagen in muscle(aids spread of bacterium)
5. Mucinase: ingests mucus coating on MMs
6. IGA protease: cleaves and destroys IGA Abs(prevent MM adhesion)
72
Toxin
poisonous substances produced by certain microbes and released into body fluids
- conditions associated with bacterial toxins in the body
1. toxemia=refers to toxins in the blood
2. septcemia=refers to persistant pathogens or toxin in the blood
3. Bacteriemia=refers to transient bacteria in the blood
4. Viremia=refers to viruses in the blood
5. intoxication=ingestion of toxins in food
6. sepsis: refers to a systemic inflammatory response due to microbes or toxins in blood spreading from focus of infection
73
two types of toxins produced or found in bacteria:
exotoxins and endotoxins
74
exotoxins
soluble proteins produced inside bacterial cells(mainly g+) and released to body fluids
cytotoxin are exotoxins that kill a variety of host cells, certain exotoxins and give examples of each.
1.A-B toxins: B part binds host cells, A, active enzyme inhibits protein synthesis and destroys host cells
ex: diptheria toxin
2. Membrane Disrupting Toxins: disrupts host membranes and lyse/kill host cells. ex. diphtheria toxin
3. Superantigens: Toxin non-specifically binds TH cells which release cytokines---> destructive immune response
ex. STAPH TSST-1 toxin
75
endotoxin(lipid A)
released upon G- CW lysis/death by macrophages, and induce macrophages to secrete large amounts of cytokines in host body fluids at toxic levels, leading to destructive/damaging immune response
76
list some important damaging immune responses in the human host that are due to endotoxins
1. hemorraging under the skin
2. DIC
3. pyrogenic response
4. endotoxic/septic shock
77
Microbial diseases of the skin
1. Diptheroids
2. Staphylococci
3. Malassezia Furfur
