Infection & Disease Flashcards
1
Q
Symbiosis.
A
living together
2
Q
Mutualism.
A
both benefit
3
Q
Commensalism.
A
one benefits and the other is uneffected
4
Q
Synergism.
A
better together
5
Q
Parasitism.
A
one benefits/other is harmed
6
Q
Normal Flora.
A
all microbes that normally live on or in the healthy body without causing disease
7
Q
How many human cells in the body?
A
10 trillion
8
Q
How many microbial cells in the body?
A
100 trillion
9
Q
What kind of normal flora is in the large and small intestines?
A
E. coli
Enterobacter
10
Q
What kind normal flora is on the skin?
A
Staphylococci
11
Q
What kind normal flora is in the month?
A
Staph
Strep
Spirochetes
12
Q
What kind normal flora is in the nose/upper respiratory tract?
A
Staph
Strep
Cornebacteria
13
Q
What kind normal flora is on the genitals?
A
Staph
Lactobacilli
14
Q
Where should normal flora NOT be?
A
- circulatory system (blood)
- internal organs
- central nervous system
- bladder
- stomach (may not be sterile)
- fetus (we acquire them a few days after birth)
15
Q
How does a baby obtain normal flora?
A
birth canal contact with instruments bottle feeding nursing contact with people
16
Q
What is the benefit of normal flora?
A
prevent pathogens from establishing site of infection
17
Q
What benefits does E.coli and ?other?intestinal bacteria give us?
A
- produce vitamin K
- intestinal bacteria help break down fibre
- intestinal bacteria alter out gene expression
18
Q
What occurs from destruction or translocation of normal flora?
A
usually results in infection (UTIs, vaginal yeast infections, diarrhea/colitis, toxic shock, staph infections)
19
Q
Infection.
A
“to mix with”
- invasion of the body by a pathogenic organism
20
Q
Disease.
A
“living apart”
- any change from a state of good health
21
Q
Pathogenicity.
A
“suffering”
- ability of a parasitic microbe to infect and bring about a disease; includes severity of the disease
22
Q
Virulence.
A
“full of poison”
- the degree of pathogenicity
23
Q
Avirulent.
A
do not cause disease
24
Q
What are the 5 stages of disease process?
A
- period of incubation
- period of prodromal symptoms
- period of acme
- Period of decline
- Period of convalescence
25
Incubation period.
time from initial contact with pathogen to appearance of symptoms
- affected by many factors (infection #, gen. time, virulence, host resistance)
- usually 1-30 days
26
What factors influence incubation period?
- affected by many factors (infection #, gen. time, virulence, host resistance)
27
How long is the incubation period?
1-30 days
28
Incubation period of Salmonellosis.
less than a day
29
Incubation period of influenza.
1 day
30
Incubation period of Cholera.
2 days
31
Incubation period of Genital herpes.
5 days
32
Incubation period of Tetanus.
3-21 days
33
Incubation period of syphilis.
2-4 weeks
34
Incubation period of Hepatitis B.
1-6 months
35
Incubation period of AIDS.
1-8 years
36
Incubation period of Leprasy.
10-30 years
37
Prodromal period.
- started to fight
- feeling unwell
- general symptoms
38
Acme period.
- acute illness stage
- characteristic symptoms of illness become apparent
- fever & chills
- most transmissible period
39
Which period is the most transmissible?
Acme period
40
Decline period.
- symptoms decrease in severity
| - sweating
41
Convalescent period
- recovery period, but still sick (immune system still ramped up and made a lot of antibodies, replicated lots of cells)
- susceptible to re-infection or secondary infection
42
What are the modes of transmission?
Direct transmission
| Indirect transmission
43
What types of direct transmission are there?
Involve one ore more of the following...
- Direct physical contact
- Inhalation of respiratory secretions
- Animal bites
- Congenital transfer
44
Direct physical contact.
hand to hand, mouth, nose, or eyes; kissing, sexual intercourse
45
Inhalation of respiratory secretions.
inhalation of tiny aerosol droplets during talking, sneezing, coughing (less than 1 meter)
46
How close do you have to be to get infected by inhalation of respiratory secretions?
less than 1 meter
47
Animal bites.
direct from infected animal to human
48
Congenital transfer.
from mother to child via placenta or birth canal
49
What are some examples of things that are congenitally transferred?
rubella, herpes
50
Indirect transmission.
infectious agent passes from infected host to intermediate object or substance and then on to another host
51
What is another name for direct transmission?
vehicle transmission
52
What is the intermediate object called in indirect transmission?
fomite or vector
53
Fomite.
Inanimate (non-living) objects that carry pathogens
54
Vector.
Live organisms that act as vehicles (are usually anthropods)
55
Examples of fomites.
waterborne
food borne
small airborne particles
56
Evaporated particles pf mucus or dust travel more than ___ and remain airborne for __ ___.
1 meter
| long periods
57
Examples of vectors.
insects (mosquitos, ticks)
58
Biological vector.
part of life cycle of the pathogen requires the vector (mosquitoes)
59
Mechanical vectors.
lives on or is harboured; not essential for life
| ticks
60
Reservior of infection.
any place where pathogen can live
61
Living reservoirs include.
human and animal
62
Non-living reservoirs include...
soil
water
food
fomites
63
What is the most important reservoir for human infections?
other humans
| - have disease or carriers
64
Carriers.
special type of human reservoir; have the pathogen (colonized), but show no symptoms of disease but can spread to other ppl
65
Most transmissible in acme stage, except...
when they are carriers and they shed the disease with no outward signs
66
Epidemiology.
science dealing with disease FREQUENCY and DISTRIBUTION in a population
67
What is the measurement of health and disease important for?
- identifying new disease
- identifying impact (importance) of diseases
- allocating resources to deal with disease
- preventing disease
68
What do you need to look at to determine disease frequency?
- defined pop.
- defined case
- source of info identified
- use of a systematic approach
69
Mortality rate.
-Number of DEATHS due to the disease per 1,000 or 100,000 people for a given time
70
Incidence
number of NEW cases of a disease in a given area or population during given time period; estimates risk of getting the disease
-per 1,000 or 100,000 people
new cases/number at risk
71
What is the difference between mortality rate and incidence?
MORTALITY is death rate in general and INCIDENCE just looks at new cases; gives an estimate of risk of getting the disease
72
Prevalence.
TOTAL NUMBER of cases of a disease in a given area or population during a given period of time
new and old cases/number of ppl at risk
73
Endemic disease.
Constantly at a low level in a given geographical area
74
Sporadic.
few scattered cases occur within an area or population
75
Epidemic.
greater than normal number of cases in an area with a given period
76
Outbreak.
a more contained epidemic
77
How do you track epidemic diseases?
Epi curves
78
Pandemic.
World wide epidemic of specific disease; infection in 3 different countries within 2 different continents
79
How many phases does WHO use for pandemics?
6 phases
80
Communicable.
can be spread from person to person
81
Contagious.
can spread from person to person (contact usually not required)
82
Noncommunicable.
not spread by person to person
83
Example of noncommunicable.
Tetanus
84
Examples of communicable diseases?
HIV
Chlamydia
Cholera
MRSA
85
Examples of contagious disease.
Common cold
Chicken pox
Measles
Rubella
86
Acute infection
rapid onset, climax rapid recovery
87
Chronic infection.
slow onset,longer duration
88
Primary infection.
First or original illness
89
Secondly infection
another infection in weakened individuals
| ex. got flu now had pneumonia...the secondary infection
90
Local infection.
infection confined to a single area of the body
91
Systemic infection
infection enters the blood stream and/or spreads to the tissue
ex.bacteremia (septicemia)
92
Bacteremia.
bacteria in blood
93
Viremia.
virus in the blood
94
Nosocomial infection.
infection acquired in the hospital
95
How many deaths due to nosocomial infections?
approx. 15000 death/year
| 5% nosocomial infections
96
Exogenous nosocomial infection.
brought in to the hospital or seeing from outside (pt, staff, etc.)
97
Endogenous nosocomial infection.
infectious agents already present in the health care setting
98
Iatrogenic Infections
caused by either medical procedures (improper hygiene or aseptic technique, or equipment)
99
3 super infections generally resistant to antibiotics.
MRSA
VRE
C. difficile
100
What factors influence nosocomial infections?
- presence of microbes in hospital environment
- immunocompromised pts
- transmission of pathogens btw safe, pt, and other pts
101
What is used to control nosocomial infections?
universal precautions
| - proper hand washing
102
5 Generalized events in establishment of disease.
1. an infectious does of microns penetrates host's defensive barrier
2. Microbe enters host tissue
3. They move into specific target tissue
4. Her they cause tissue damage, leading to disease
5. Microbes leave host via portal of exit to infect another host
103
Portal of entry.
where pathogens enter the body
104
Ex. of portal of entry
- eyes, nose, mouth, ears
- skin lesion (insect or animal bite)
- urethra, anus
105
Portal of exit.
how pathogens sleaze the body
106
Ex. portals of exit.
- coughing/sneezing
- removal of blood
- by insect bite
- in the faces
- in the ring
- through an open lesion
107
Factors contributing to disease.
Susceptibility of host
Dose
•infectious dose required
Virulence factor
108
How many typhoid bacilli are required for infection?
200 thousand
109
How many cholera bacilli are required for infection?
2 million
110
Virulence.
Relative ability of pathogen to cause disease
111
What is virulence determined by?
ability of microbe to penetrate & multiply in hose
| - toxicity
112
Toxicity.
Ability of microbe to generate harmful toxin.
113
What are the virulence factors?
adhesions
extracellular enzymes
toxins
114
Adhesions.
on pili, cell wall, outermsmbrane, capsid, spikes
| - can induce phagocytosis or endocytosis
115
Name some extracellular enzymes.
```
Coagulase
Kinases
Hyaluronidase
Leukocidins
Hemolysins
```
116
Coagulase.
protective wall around bacteria that clots plasma
| eg. Staphylococcus aureus
117
Kinases.
enzymes that dissolves (lyse) blood clots
| eg. streptokinase produced by streptococcus pyogenes
118
Hyaluronidase.
dissolves hyaluronic acid which holds tissue together, so microbes can spread rapidly
119
Leukocidins.
proteins that destroy WBCs
| - induce release of lysosomal enzymes
120
Hemolysis.
enzymes that destroy RBCs (strep series)
121
What is often used to identify bacteria?
extracellular enzymes
122
If you are coagulase positive you have...
staph
123
Pathogenicity islands.
clusters of genes that code for pathogenicity
124
How are pathogenicity islands transferred?
Horizontal gene transfer (between bacterium)
125
Endotoxins gram +ve or -ve?
gram negative
126
Exotoxins gram +ve or -ve?
gram positive
127
Exotoxins.
actively made by bacteria and sent OUT
128
Endotoxins.
made and remain in the outer membrane unless they breakdown or lyse
129
Mode of action of Exotoxins.
tissue specific; destroy tissue or alter chemical production/release
130
Mode of Endotoxins.
induce blood clots and activate complement system (systemic inflammation)
131
When endotoxins are severe it is called..
endotoxic shock
132
Endotoxic shock
tissue swelling, drop in BP, antibiotic induced
133
What does the immune system produce to fight toxins?
antitoxins
134
Where are antitoxins made?
the immune system
135
What are the characteristics of Exotoxins.
- made of protein
- released by secretion
- mainly gram +ve
- high potency
- toxic effect (very specific)
- immune response is strong
136
What are the characteristics of Endotoxins.
- made of lipids/carbs
- released when cell disintegrates
- gram -ve
- low potency
- nonspecific toxic effect
- weak immune response
137
Examples of Exotoxins.
Neuromuscular toxins
| ex. botulism, diphtheria, tetanus
138
What does botulism (gram +ve) cause?
muscle paralysis
139
What does (gram +ve) diphtheria cause?
nerve/myocardial destruction
140
What does tetanus (gram +ve) cause?
muscle spasms
141
Examples of Endotoxins (gram -ve)(LPS).
```
Dysentery
Meningitis
Typhoid fever
Cholera
- all produce fever, diarrhea, vomiting, endotoxic shock
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