Unit 1 Flashcards
1
Q
What are virulence factors?
A
- what makes a pathogen a pathogen
2
Q
What is zoonosis?
A
- animal to human transitions
3
Q
What is immunology?
A
- how the body fights off invaders
4
Q
What are the two main types of medical micro?
A
- clinical medicine and public health
5
Q
What is clinical medicine?
A
- diagnosis and treatment
6
Q
Who introduced the germ theory?
A
- thucydies and fracastoro
7
Q
What is the germ theory?
A
- miasmas (bad smells) get you sick
8
Q
Who discovered the first microbes?
A
- leeuvenhoek
9
Q
What hapens in the 1800s?
A
- pastuer disproves spontaneous generation and Koch says specific organisms cause specific diseases
10
Q
What are the main causes of infection in the present?
A
- bacteria, fungi, viruses (RNA and DNA)
11
Q
- what are always in the top 10 causes of death?
A
- lower respiratory diseases, diarrheal diseases, TB
12
Q
Do humans have more microbial cells or human cells?
A
- 2x3 times more microbeal cells and 150x more microbial genome than human genome
13
Q
What makes up the microbial cells?
A
- human virus cells, viruses of other cells like bacteria, acellular viruses, archaea, eukaryea, bacteria
14
Q
What is the difference between the microbiota and the microbiome?
A
- the microbiota is the microbes themselves while the microbiome is the genomes of the microbes?
15
Q
What is the relationship between human and their microbiota?
A
mutualistic or commensalistic
16
Q
What is colonization?
A
- microbes grow on but don’t cause disease
17
Q
Does the human bicrobiota colonize?
A
yes
18
Q
Is the human microbiota permanent or transient?
A
either
19
Q
Is the human microbiota always the same?
A
no, different composition based on environment and lifestyl
20
Q
What is the job of the human microbiota?
A
- promote the immune system
- protect against pathogens
- form metabolites through fermentation
- aid in digestion
21
Q
How does the human microbiota protect against pathogens?
A
- by niche competition, they take up space the pathogens need
22
Q
Where should microbes be found?
A
in areas that come in contact with the environment
- stomach, respiratory, and urogenital all come in contact
23
Q
What are some sterile sites of the human body>
A
- blood
- csf
- synovial fluid
- organs that only have blood going through them
- pleural and pericardial fluid
- bones and joints
24
Q
What is the pleural fluid?
A
- fluid between membrane lining lungs and the lungs themselves
25
What is pericardial fluid?
- fluid between pericardium and pericardial sac and heart
26
If your own microbes get into a sterile site is it sitll an infection?
yes
27
How do sterile sites stay sterile?
- through the immune system
28
What are passive forms of immune defense?
- skin. mucous, epithelium
29
What are active forms of defense?
enzymes, ciliated epithelium, immune cells
30
What is another term for host-microbe interactions?
symbiosis
31
What is a host?
- usually the patient
- supports growth of the other organism
- typically larger or multicellular
32
What is a microbe?
- too small to be seen by the unaided eye
- most commonly bacteria or viruses
33
What are cellular microbes?
- bacteria, archaea. protozoa, fungi, parasitic worms
34
What are acellular microbes?
- virses and prions
- have no plasma membrane or ribosome
35
What is the typical symbiotic relationship of the skin?
- commensalism
- microbes colonize host and the host gets nothing
- microbes get food, stable environment, not a lot of competition
36
What type of symbiotic relationship is the gi tract?
- microbe gets food and stable environment
- host gets vitamins, protechtion from pathogens and immune stimulation
37
What type of relationship is all viruses and intracellular bacteria with humans?
- parasitism
- microbes get food and favorable environment
- host gets damage to cells, tissues, and disease
38
Does parasitism require over disease to be observed?
- no
- could still kill some cells without us noticing
39
What is disease?
- abnormal state of host where normal structure and functions are damaged or impaired
40
What is pathogenesis?
- steps or proecss of developing a disease
41
What is a pathogen?
- any microbe that causes a disease or infection
- parasitic
42
What is an infection?
- etiological agent of disease
43
What are the types of parasites?
medical or ecological
44
What is an ecological parasite?
- any organism in parasitic symbiosis with another
45
What is a medical parasite
- disease causing protozoa/ worms (endoparasites) or fleas/ lice) ectoparasite
46
Is infection transient or chronic?
- typically transient but could be chronic
- most cause disease but doesn't have to
47
What is an infection where no disease occurs called?
- subclinical
- asymptomatic,
- inapparent
48
What are signs?
- objective/ measureable (temp/bp)
49
What are symptoms?
- subjective, felt/experienced
- pain. energy level
50
What is a syndrome?
- signs and symproms experienced together
51
Do all pathogens cause disease?
- no
52
What is pathogenicity?
- capacity of microbe to cause disease
53
What is virulence?
- extent/ severety f disease caused
54
What is infectivity?
- ease at which microbes can enter a sterile site
55
What is a virulencec factor?
- charecterists of a microbe that allow it to cause disease
56
What is the host range?
- spectrum of hosts a micorbe can replicate in
- narrow = not many
57
What is an obligate pathogen?
- presence is associated with overt disease
- will cause disease in healthy people
- never part of human microbiota
58
What is an opportunistic pathogen?
- requires predisposing factors to become disease causing
- causes disease in immunocompromised indiciduals
- not always associated with disease
59
What type of pathogen is bacteria?
- some obligate
- many opportunistic
60
What type of pathogen is a fungi?
- few obligate
- mostly opportunistic
61
What type of pathogen is a viruses?
- most obligate
62
What type of pathogens are all other microbes?
obligate
63
What are exogenous infections?
- infection comes from microbes coming from outside host
- all obligate pathogens and many opportunistic
64
What are endogenous infections?
infection from microbes typically in host
65
What are the mechanisms of host pathogen interactions?
1. exposure and pathogen entry
2. tissue attachment and infection
3. immune avoidance
4. damage to host
5. exit/ shedding
66
What is a communicable disease?
- can spread from person to person
67
What is required for all the steps of host-pathogen interactions?
- expression of virulence factors
68
What does differentiation in variabilty and production of virulence factors cause?
- difference in disease and severity
- could vary within a species
69
What produces exotoxins?
bacteria
70
What are exotoxins?
- made by bacteria and acts at a distance to host cells causing damage
71
What is a portal of entry?
- where a pathogen gets in
72
How many portals of entry does a pathogen have?
most have 1
73
Where are mucous membranes?
- gi tract
- respiratory tract
- urogenital tract
- conjunctiva
74
What type of portal of entry is the most likely?
- mucous membranes
75
What is the parenteral portal of entry?
- injection/ mechanical
- insects or needle sticks
76
What is the infectious dose?
- amount of organisms on average to cause disease
- can vary based on host and microbe
77
What is the ID50?
- amount of organisms needed to affect 50% of hosts infected
- lower the ld50 the more infective
78
What is adherence?
- sticking of molecules are key virulence factors
- can be specific like lock and hey or non-specific using electrostatic mechanisms
79
What is highly specific adherence?
- smaller host range and tropism
80
What is a tropism?
- different cells and tissues could be affected by microbe
81
How to viruses bind?
- attachment protein
- highly specific
82
How do bacteria, fungi, and parasites bind?
- using adhesins
- all have different specificities
- usually proteins
83
Where do bacteria typically have adhesins?
- fimbriae and cillia
- adhesion sticks to cell surgace and cillia serve as an anchor
84
Are bacteria, fungi, parasites extracellular or intracellular?
- mostly extracellular but have some intracellular growth
85
Where does extracellular growth happen?
- interstitial spaces, blood, lymph
86
Are all organisms extracellular?
- not all organisms can reproduce outsie a host, but most/ all have an extracellular stage
87
What lives at epithelial surfaces?
- many bacteria, most fungi, protozoa, many parasites, no virases
88
What must happen for a microbe to be intracellular?
- must penetrate in first
- applies to many bacteria, most fungi, protozoa, many parasites, but not viruses
89
How do pathogens become intracellular?
- phagocytosis for large pathogens,
- endocytosis for viruses and small pathogens
- membrane fusion for enveloped viruses.
90
How do viruses adhere to the cell?
- transiently and then enter y endocytosis and sometimes membrane fusion
- membrane fusion happens spontaneously due to hydrophobic state of lipid bilayer
91
How is endocytosis triggered?
- by binding to the host cell
92
What is a cellular pathogen?
- bacteria, fungi, protozoa
93
What happens after a virus becomes intracellular?
- needs to get out of vesible and into cytoplasm by genome injection, membrane fusion, and lysis of vesicle
94
How do cellular pathogens enter the cell?
- phagocytosis triggered by pathogen binding
95
What type of cells can be infected by bacteria, fungi, protozoa?
- phagocytic cells only
- typically macrophages
- but some bacteria and protozoan parasites can make non-phagocytic cells take them up (but rare )
96
What is required for cellular pathogens to survive inside a phagocytic cell?
- virulence factors
97
What is the key difference between cellular and viral uptake?
- viruses use endocytosis and cellular use phagocytosis
98
What is vesicular uptake?
- made and grow in vesicle then vesicle then vesicle dies and microbes can come in
- done by most bacteria, a few fungi, most protozoan parasites, no viruses
99
What is cytoplasmic uptake?
- vesicel could be intact or destroyed
- done by no fungi, few bacteria, few protozoan parasites, or all viruses
100
How can cells survive phagocytosis?
- escaping phagosome
- using virulence factors to stop phagolysosome fusion
- allow phagolysosome fusion but use virulence factors to stop digestion
101
What is local invasion?
- spread of pathogen only occurs in a restricted location at or near point of entry
- extent of infection is restricted, but pathogen is not confined to outer layer of cells
- no invasion of tissues, only outer epithelial affected
- mostly extracelllular
- normal barriers of infection are breached (intracellular or extracellular) or circumvented (intracellular)
- viral or cellular
102
How does local invasion spread?
lateral spread, if they leave they leave from the same side they came in
103
What does breached mean?
cells go between and under epithelial, could go through using toxins, but cell will be killed
104
What does circumvented mean?
cell is kept alive and not damaged structurally
105
Can local invasion do breaching and circumventing?
yes
106
What does facultative mean?
- could live intracellularly or extracellularly
107
What are the types of facultative invasion?
- induced phagocytosis
- transcytosis
108
What is induced phagocytosis?
- pathogen taken up into epitheleal cell, pathogen released into underlying tissue
109
What is transcytosis?
- vesicle transverses epithelial cell, pathogen released into underlying tissues
- doesn't infect cell, just travels through it
- circumvention
110
How does breaching/ circumventing happen?
- enzymes to break down ecm
- toxins kill epithelial
- proteins to introduce transcytosis
111
How do pathogens evade and counteract host immune responses to survive in sterile sites?
- bacterial capsules
- ability to survive phagocytosis
112
What does disseminated mean?
- systemic and widespread of microbe after local invasion at or near point of infection
113
How does a pathogen diseminate?
- immune system fails to contain infection and keep it localized
114
Is dissemination normal for pathogens?
- normal for some not for others
115
Do pathogens cause the same disease locally and disemminated?
- systemic disease is typically more severe than localized
- pathogens can cause different disease in different spots
116
Can a localized infection cause systemic disease?
yes
117
Does dissemination depend on host or pathogen factors?
- both
118
What are the routes of disemeniation?
- primarily blood in lymph
- intracellular pathogens can be carried inside mobile host cells like macrophages and dendritic cells
119
What are the pathogens in blood stream called?
- bacteremia
- viremia
- parasitemia
- fungemia
120
What causes overt disease?
- host tissue/ organ damaged
- damage can be done by pathogens or responses by immune system (immunopathology)
121
How is the host cell killed?
- secreted enzymes like proteases and phsopholipases
- excreted metaboites like organic acids
- cytolytic exotoxins
122
What pathogen secretes enzymes?
bacteria
fungi
protozoa
123
What pathogen uses cytolytic exotoxins?
bacteria
124
What renders the host cells non-functional?
-cytotonic exotoxins secreted by bacteria
125
What helps with pathogenesis?
- proteins made by bacteria
126
What are cytolytic bacterial toxins?
- directly results in cell death by disrupting cell membranes or protein synthesis
127
What is cytotonic bacterial toxins?
- changes in host cells without death by disrupting signal transduction and cellular targets
128
What are AB toxins?
- cellular acting toxins where A is toxic and B is delivery service
129
What type of bacterial toxin is diptheria?
- extracellular
- inhibits protein synthesis to cause cell death
- a1b1
- similar to other toxins because of horizontal gene transfer
130
What is an enterotoxin?
- toxin that has its affect in the gi tract
131
How does host cell killing take place
they grow in the cell and then released
diversion of cell resources
132
How is the host cell made non-functional?
- diversion of resources from the cell
- oncogenic transformation (tumors)
133
What is immunopathology?
- unregulated killing of host cells by the immune system triggered by pathogen presence
134
What underlies immunopathology?
- inflamation, heat, pain, swlling
- caused by cytokines
135
Are local cytokines good?
yes
136
Are distant cytokines good?
no, very bad
137
What do endotoxins do with immunopathology?
- trigger cytokine production and deal with bacterial cell wall
138
what is a cytokine storm?
- large number of systemic cytokines
139
What are type 4 hypersensitivity reactions?
- rashes due to t-cells producing cytokines in tissues
140
What is type 3 hypersensitivity?
- due to chronic infections
141
How do pathogens typically leave?
- via port of entry
142
Do disseminated infections contribute shedding?
sometimes
143
Do diseases enhance shedding?
- sneezing and diarrea help spread
144
Do pathogens infecting a dead end shed?
- no, either not shed or shed in insufficient amounts to affect a new host
-
145
What is a dead end?
- terminal
- refers to host species, not just host
- once infected it doesn't infect anything else
146
Are vectored pathogens shed from all hosts?
- not from all hosts
- depends on pathogen in blood
147
What do the details of pathogen spreading determine?
- routes of efficiency of transmittion to new host
148
What is the incubation period?
- time from entry into host until onset of disease
- infection begins to adhere
149
What is the podromal phase?
- none-s[ecific effects
150
What is the illness phase?
- overt affects
151
What is the convalescent phase?
- body repairs damage
152
What is acute disease?
- rapid onset to recovery
153
What is sequale 2?
- diseases that may follow infection
154
What are the outcomes of disease?
- resolution
- death
- persistant infection
- latent infection
- clinical latency
- true latency
155
What is persistant infection?
- asymptomatic = carrier state or chronic disease
156
What is a latent infection?
- hidden infection
157
What is clinical latency?
lack of overt disease
158
What is true latency?
no pathogen reproduction
159
Can latent infections be reactive and cause disease?
yes
160
