Unit 2 Flashcards
(218 cards)
1
Q
Why does DNA replication, transcription and translation in bacteria provide targets for antibiotics?
A
Because even though the process is relatively the same, different enzymes are responsible
2
Q
What are three ways in which bacteria can be naturally resistant? Only a few types of bacteria are naturally resistant.
A
- mycolic acid
- drug efflux pumps
- secretion of toxins and antitoxins (so that they aren’t harmed by their own toxins)
3
Q
How can bacteria become resistant to antibiotics?
A
mutations can occur in their genes
4
Q
Beneficial mutations (like antibiotic resistance) are _____ times less common than detrimental mutations
A
100
5
Q
What are three ways by which the problem of antibiotic resistance has reached its current scale?
A
- binary fission
- natural selection
- gene transfer
6
Q
What are two ways in which natural selection is promoted in bacteria?
A
- overuse of antibiotics in humans
2. use of antibiotics in animal feed
7
Q
Is gene transfer among bacteria rare?
A
No, it is rampant
8
Q
What is transposase?
A
an enzyme that allows for the splicing in and out of a bacterial chromosome
9
Q
What is an F plasmid?
A
A fertility plasmid, it causes the bacteria to sprout pili and it promotes conjugation
10
Q
What is conjugation?
A
Both the donor and the recipient are alive. Hollow pili (sex) mediate attachment and a copy of the F plasmid is made and sent through the pili to the recipient.
11
Q
Does conjugation occur during DNA replication?
A
Yes
12
Q
How long does it take for conjugation to occur?
A
10 min
13
Q
What is transduction?
A
The process by which a donor cell with an AB resistant gene is infected with a virus that splices into and out of the chromosome taking the AB resistant gene with it. The virus will eventually cause the cell to lyse. The viral DNA will be released and can splice into another cells chromosome giving them the AB resistant gene
14
Q
How do viruses avoid exonucleases if they are linear segments of DNA?
A
They fold their ends in order to appear circular.
15
Q
In transformation how are other bacteria aware of the fact that the bacteria has died?
A
The ATP spilled out with the rest of its contents acts as a signal to let them know that genes are available
16
Q
How do the live bacteria “pick up” the lysed cells genes?
A
- secrete autolysin (which creates holes in their cell membrane)
- secrete endonuclease which cut up the chromosome
- They insert a DNA binding protein into their plasma membrane
- They express an eclipse complex (like carrier proteins)
17
Q
What is an operon?
A
gene sequences that are found together and code for a protein that can be turned on or off
18
Q
What is a repressor? What does it do?
A
It is a protein that attaches to operator sequences in order to stop the synthesis of certain proteins/products
19
Q
Inducible operons
A
default off, nutrient attaches to repressor to turn it on, when the enzyme is needed to act on this nutrient. break things down
20
Q
Repressible operons
A
default on, when there is nutrient available and it doesn’t need to be synthesized a repressor will bind to turn these off. synthesize things
21
Q
Constitutive operons
A
Always on, because they are for things that the cell will always need
22
Q
What would be a good way to regulate constitutive operons?
A
Antibiotic could fit and act as a repressor
23
Q
Are fungi procaryotic or eucaryotic?
A
They are eucaryotic
24
Q
What intracellular components make up fungi?
A
true nucleus, numerous organelles, cell wall, and ergosterol in PM
25
What is a fungal cell wall made up of?
chitin and glucan
26
What is a colony of fungi called?
a thallus
27
Most of the cells in a thallus are haploid or diploid?
haploid
28
What are the two forms in which fungal forms grow?
Filamentous and yeast
29
What is the name of a fungal colony growing end-to-end in a filament?
a hyphae
30
What is a ceonocytic hypha?
It is a hyphae in which the cytoplasms of the cell are connected, making it essentially a single, continuos hypha
31
How are nutrients diffused in a hypha?
By diffusion, capillary action
32
How do hyphae elongate?
mitosis and cytokinesis, at their tips not their bases
33
What does it mean to say that fungi can reproduce by fragmentation?
Any part of a hypha with a nucleus is capable of initiating a new colony
34
Hyphae bundle to form thicker strands called _________
mycelia
35
Vegitative mycelia
grow into underlying nutrient source, with are absorbed and easily shared with other cells in the thallus bc their cytoplams are connected
36
Reproductive mycelia
grow upwards and produce reproductive spores
37
What does the yeast form of fungi look like?
unicellular and spherical, without mycelia
38
How do yeast cells reproduce?
by budding - form a bulge on outer surface where a nucleus copy and starter set of organelles are placed which then pinch off.
39
What are reproductive spores?
they are dormant and resistant (pigmented) - stored in sporangium (full of individual spores)
40
What is histidine kinase?
It mediates between the two forms of fungi
41
What does it mean to say that fungi are dimorphic?
that they can grow in two different forms
42
When would a fungi grow into a filamentous or yeast form?
amount of N and glucose as well as temp.
43
What type of molecules to fungi need in order to grow?
Only organic, extremely versatile, any organic molecule will do. But they need frequent or occasional exposure to water.
44
What strange types of things can be metabolized by fungi? With the addition of a little bit of water
soap scum, damp leather, paint, vinyl, drywall (cellulose)
45
What does it mean to say that fungi digest externally?
They secrete enzymes into their environment which digest the material into subunits which are then absorbed into the fungi
46
Fungi are primarily to responsible for decomposing ________________ which they break down into _____________
dead plant material, sugars
47
What type of digestive enzymes do fungi secrete?
cellulase and pectinase
48
Fungi are mostly anaerobic or aerobic?
aerobic
49
yeasts are facultative _____________
anaerobes
50
If O2 is available
yeast will metabolize CHO by aerobic respiration to CO2 and H20 using O2 as a final e- acceptor
51
If O2 is unavailable
yeast will ferment CHO forming ethanol and H20
52
What type of pH do fungi prefer?
they prefer acidic environments 5.6
53
Why are fungi resistant to desiccation?
Because of their cell wall. They can grow at low moisture levels and in high salt/sugar conc
54
What is the generation time of fungi?
2 hours at 23 degrees C, 1 hour at 37 degrees C
55
What types of cells produce asexual spores?
single haploid
56
Fragments of hyphae are more or less resistant to the environment than vegetative hyphal cells? Why?
More, because the have a thickened cell wall
57
What is the simplest and least elaborate type of spore?
fragments of hypha
58
What is a sporangium?
It is a sac in which hundreds of spores form at the end of a reproductive hypha
59
How do the spores in a sporangium form?
One cell divides repeatedly by mitosis with all daughter cells becoming spores, which are then encased in a sac which eventually ruptures
60
What other types of spores do reproductive hypha produce besides sporagium?
chains of spores
61
How are sexual spores produced?
By the fusion or combining of genetically dissimilar parents from two different hyphae colonies
62
The parent cells are __________ and the zygote is _________ in sexual spore production
haploid, diploid
63
If the zygote divides by mitosis before undergoing meiosis, how many haploid spores are produced per diploid cell?
4
64
sexual spores germinate into what?
haploid hyphal cells
65
sexual spores contain ____________ chromosome combinations than their parents which is beneficial
different
66
What are mycoses?
human diseases caused by fungi
67
What does nosocomial mean?
hospital-acquired
68
What percentage of nosocomial infections are fungal?
40 %
69
What is the classification of fungal infections based on?
How deep into the body the microorganisms penetrate
70
Superficial mycoses
It is on the surface of the skin only, filamentous form
71
Cutaneous mycoses
mycelia (hyphas) growing into the keratinized, dead cells of the skin, to absorb nutrients the fungi secrete keratinase, filamentous form
72
What are examples of cutaneous mycoses?
ring worm and athletes foot
73
Subcutaneous mycoses
infection beneath the skin, spores would have to have been directly implanted by a cut or puncture, yeast form.
74
Systemic mycoses
Can affect any and all of the body tissues and organs, because they are being carried by the bloodstream, yeast form.
75
How are most systemic mycoses contracted?
By inhaling spores which then germinate in the alveoli, and can then pass into the bloodstream b/c of the narrow boundary between the alveoli and capillaries
76
What type of fungi cause histoplasmosis?
Histoplasma capsulatum
77
Describe histoplasmosis
It is a pulmonary infection that is only symptomatic in people with weak or underdeveloped immune systems most people are exposed by age 20 (can cause pneumonia or TB)
78
Where are Histoplasma capsulatum normally found?
In bird droppings, because they provide organic material, water, and an acidic environment.
79
How do histoplasma capsulatum yeast survive being phagocytosed?
The yeast cells chelate (adsorb) the Ca+2 in the phagosome, which is what activates its degradative enzymes.
80
What type of fungi cause cryptococcal meningitis?
Cryptococcus neoformans
81
Describe cyrptococcal meningitis
The fungi are inhaled and then pass into the bloodstream where they can then pass into the meninges (subarachnoid space)
82
How could cryptococcus neoformans cause encephalitis?
By crossing over the pia mater and into the nervous tissue of the brain.
83
What are two drugs that have been used to treat cryptococcal meningitis?
amphotericin B - attaches to ergosterol and rips it out of the PM (problem, it can rip cholesterol out of human cells PM). AND fluconazole - which blocks the synthesis of ergosterol, inhibiting growth.
84
What type of fungi cause candidiasis?
Candida albicans
85
Are candida albicans part of the body's normal flora?
yes
86
What type of mycosis is candidiasis classified as?
superficial
87
What is the cascade of events of Candida albicans leading to symptoms?
1. eliminate competing MO's
2. This leads to an overgrowth of yeast
3. The fermentation byproducts of yeast leads to host cell damage
4. The host cell damage leads to inflammation
5. Inflammation leads to a limiting of the spread of damage as well as the swelling
6. swelling presses on nearby nerves causing pain or itching symptoms
88
How is the elimination of competing organisms (leading to candidiasis) caused?
1. antibiotics - natural selection
2. lack of competing bacteria - newborns
3. alterations in acid or sugar in mucus
4. suppression of the immune system - chemo, cancer, malnutrition, AIDS, anti-rejection drugs (transplant)
89
What are the 4 treatment options four candidiasis and how do they work?
1. anesthetics - block pain (benzocaine)
2. anti-inflammatory - block inflammation (thereby promoting spread of damage)
3. antimicotic - blocks ergosterol synthesis, killing the fungi (miconazole - superficial administration)
4. experimental probiotic therapy - introduce competing MO's
90
Which is the only fungi that does not have ergosterol in the cell wall, but has cholesterol instead?
Pneumocystis carinii
91
What type of infection do Pneumocystis carinii cause?
Pneumocystic pneumonia
92
Describe Pneumocystic pneumonia
It is easily defeated by a healthy immune system. Nearly the entire lungs fill with fluid making it rapidly fatal in those with weakened immune systems - AIDS
93
What size are protozoans?
5-15 micrometers
94
What is the general structure of a protozoan?
A nucleus, a micronucleus, cilia, no cell wall
95
Why do protozoans not have cell walls?
Because it interferes with their ability to phagocytose
96
Why are parasitc protozoans facultative anaerobes?
Because the host has plenty of nutrients for them to survive using only glycolysis
97
How do protozoans reproduce asexually? (2 ways)
By binary fission or budding
98
How do protozoans reproduce sexually?
By conjugation - in which their haploid micronuclei are exchanged
99
What are the two most common forms that a protozoan can be found in?
1. trophozoite - active and feeding
| 2. cyst - inactive (dormant) and resistant
100
Protozoan cysts have a cell wall made up of what?
chytin
101
What type of protozoan causes amoebic dysentery?
Entamoeba histolytica (intestinal amoeba tissue lysing)
102
How do E. histolytica cysts make it into the small intestine?
They are swallowed, and they are resistant to stomach acid
103
What do the Entamoeba histolytica in the small intestine?
They undergo mitosis three times to produce eight trophozoites, because there are plenty of nutrients available
104
How is it that Entamoeba histolytica produce ulcers? What shape are these ulcers?
They attach themselves to the intestinal wall and digest their way into it. As they reproduce they release lytic enzymes which create ulcers. They are flask-shaped due to the expanding population of protozoans.
105
Why do Entamoeba histolytica result in dysentery?
Because they block water reabsorption, this allows them to spread.
106
Why could dysentery be fatal?
Because up to 9.2 Liters of water could be lost a day, and that water is coming from the blood stream which results in a drop in blood volume -> drop in blood pressure -> can be fatal
107
What are the three parts of infectious disease spread?
1. reservoir 2. route of transmission 3. susceptible host
108
Can a bacteria makes its way into a host by being inside of a trophozoite/cyst?
Yes
109
What is the name of the protozoan that causes toxoplasmosis?
Toxoplasma gondii
110
What do Toxoplasma gondii look like?
They are cresent-shaped
111
What is the primary host (reservoir) of Toxoplasma gondii?
Cats
112
How can a person become infected with Toxoplasma gondii?
Change litter box -> fail to wash hands -> end up ingesting cysts. Will only be symptomatic is immune system is weak
113
What type of cells do Toxoplasma gondii cells often infect ?
They live inside of macrophages
114
Why is it super important for a pregnant woman to not change a cat's litter box?
Because she could ingest cysts which would be asymptomatic in her, but could cause brain damage in the baby, and possibly even a miscarriage
115
What type of symptoms do people infected with Toxoplasmosis generally display? What is the greatest danger?
Mononucleosis-like symptoms. The greatest danger is a CNS infection.
116
What are the CNS symptoms in AIDS patients with toxoplasmosis?
paralysis, confusion, vision or hearing loss, possibly coma
117
What type of protozoan causes Giardiasis?
Giardia intestinalis (used to be Giardia lamblia)
118
How is Giardiasis transmitted? (give 3 specific routes)
Via a fecal - oral route
1. poor water treatment
2. lack of hygiene in daycare workers
3. drinking out of a stream while hiking.
119
What is metronidazole for?
It is used to treat severe cases of Giardiasis
120
What is the structural composition of Giardia intestinalis?
They flat and light bulb shaped. With two full-sized nuclei and 4 pairs of flagella. They have no mitochondria, or micronucleus. They have an adhesive disk on their outer surface.
121
Will Chlorinated water be likely to have Giardia intestinalis in it?
There is a large chance that it will, because Giardia intestinalis are relatively resistant to chlorine.
122
What is the morbidity rate of Giardiasis?
> 60 %
123
What is the mortality rate of Giardiasis?
< 0.1 %
124
How and where is the adhesive disk of Giardia intestinalis activated after cysts have been ingested by the host?
They are activated by trypsin in the small intestine
125
What is the incubation period of Giardiasis?
1 - 4 weeks
126
What are the symptoms of Giardiasis?
Vary from mild indigestion and nausea for a few days, up to vomiting, diarrhea, gas and stomach cramps for several weeks
127
How can Giardiasis be prevented? ( 4 ways)
1. water filtration
2. boil water for 1 min
3. add a few drops of bleach per quart of water
4. drugs available (but have side effects)
128
What does the word malaria mean?
Bad, air condition
129
What type of protozoans cause Malaria?
4 intracellular Plasmodium species, including P. vivax and P. falciparum
130
What is the morbidity rate of Malaria? What is the mortality rate?
morbidity - 25 %
| mortality - 0.2 %
131
What disease does Malaria predispose a person to?
HIV
132
How do Plasmodium sporozoites get into a human host's bloodstream?
Via the female Anopheles mosquito
133
Once inside of the human host, what do Plasmodium sporozoites do?
They enter the liver within 10 minutes and rapidly reproduce asexually into merozoites (some become dormant hypnozoites). After 1-2 weeks the liver cells rupture and the merozoites enter RBC's and become trophozoites
134
What is the cycle involving Plasmodium merozoites, RBC's and Malaria symptoms?
The merozoites enter the RBC's and become trophozoites and in 2-3 days reproduce from 1-20 trophozoites. This causes the RBC's to lyse (which is what causes the Malaria symptoms). The merozoites will then enter new RBC's and the cycle will repeat itself
135
What are the symptoms experienced with Malaria?
1. Cold and Shivering
2. High Fever (103-106)
3. Exhaustion
4. Anemia
5. Lysed or aggregated RBC's can cause blood clots
Symptoms are only exhibited when RBC's lyse, so every -3 days
136
How is it that a mosquito can pick up the Malaria infection from the human host?
Merozoites will begin to reproduce sexually and form gametocytes in the RBC's. These gametocytes will fuse to the mosquitos intestineand form diploid zygotes. Which then undergo meiosis forming haploid sporozoites and go to the salivary glands of the mosquito
137
What does ACT (artimesinin combination therapy) do?
Heme is toxic to Plasmodium trophozoites, but they have a mechanism to block heme. ACT blocks their block, so that they can be destroyed by the heme
138
What is the ACT treatment for Malaria made up of?
quinine derivatives (chloroquine and primaquine) and artemesinin
139
What are the two ways of preventing Malaria via the route of transmission?
1. pesticides to kill mosquitos
| 2. bed nets
140
What are the 3 problems in the way of a vaccine development for Malaria?
1. the protozoan is almost always intracellular
2. it changes its antigens
3. RBC's lack MHCT proteins (immune system receptors)
141
Why is irradiated sporozoites not a practical idea for a Malaria vaccine?
It would involve dissecting the salivary glands of mosquitos
142
What vaccine do we have available now for Malaria?
RTSS - sporozoite antigen produced by bacteria, the only problem with this is that it is only 35 % effective.
143
What are the parts that make up a virus?
1. tiny wisp of DNA or RNA
2. capsid (protein coat)
3. single, single, enzyme or transcription factor
4. some have a membrane (envelope)
5. spike proteins
144
Can a virus be treated with an antibiotic?
No, because viruses are not formed by the growth and division of another virus, they are entirely resistant to antibacterial antibiotics
145
How do viruses survive with so few intracellular components?
They have to obtain all other essential materials from a host cell
146
Which host cells a virus can infect depends on what two things?
1. the right receptors
| 2. access to those cells
147
How do host cells have receptors for viruses?
The spike proteins in the capsid (or envelope) of the virus are complementary to certain proteins in the plasma membrane (or cell wall) of prospective host cell.
148
How small are viruses in comparison to other cells?
They are approximately the size of a ribosome.
149
How much DNA does a viral genome have?
3000-250000 bases
150
What 3 shapes are possible for a virus to have?
1. helical
2. polyhedral
3. complex
151
Are viruses specific in the type of bacteria or host cell that they infect?
Yes
152
What is a complex virus made up? How do they infect host cells
A polyhedral head, pressurized nucleic acids, a tail core with a sheath, and tail fibers. They attach to the host with the tail fibers and then jab through the cell wall or membrane with the tail core and the nucleic acid which is pressurized, shoots into the cell.
153
What is the first step of viral multiplication in animal and human cells?
It's spike proteins attach to the receptor proteins on the cells PM
154
The second step of viral multiplication is penetration which can be done in what 2 ways?
1. endocytosis of the bound receptors
| 2. fusion of an enveloped virus to cells' PM
155
Once inside of the cell, what immediately happens to the viruses?
The capsid falls apart and the nucleic acid is released into the cytoplasm or nucleus.
156
How do DNA-containing viruses transcribe their DNA?
They use the host cell's RNA polymerase (DNA-dependent)
157
How many of each virus component is made during viral multiplication?
At least 10,000 of each component
158
Viral DNA is replicated using ________ polymerase
DNA
159
What is the viral mRNA (transcribed from viral DNA) used for?
It is translated by the host cell's ribosomes into new viral proteins
160
What type of virus is capable of splicing into a host cell's chromosome?
Only double-stranded DNA containing viruses
161
What occurs to ssRNA viruses?
The RNA can generally act as mRNA directly and be translated into a number of viral proteins or it will be replicated into more ssRNA to be encapsulated
162
What are endogenis retroviruses?
They are harmless viruses, that have no affect on the host cell
163
What is the enzyme used by viral DNA to splice into the host cell chromosome?
transposase
164
What are the 3 sources of DNA polymerase that a DNA virus can use to replicate itself?
1. could be available if host cell is replicating its DNA
2. the virus can force the host cell to express it, using it's transcription factor
3. the virus brings it along
165
What is the fate of a dsRNA in a host cell?
It will use reverse transposase (which they bring along) to make ssDNA which will become dsDNA using DNA polymerase. From here it can be spliced into the host using integrase. Or it will be encapsidated or be used to produce new viral proteins
166
How does the assembly of viral components to create new viruses occur?
It is spontaneous when the cytoplasm is full
167
What are the 2 ways that new virus particles are released from host cell?
1. cell membrane ruptures
| 2. by budding from the PM, acquiring an envelope in the process
168
What are the 4 causes of a lytic infection (host cell death or lysis)?
1. ruptures in the PM
2. continual inhibition of host cell RNA and protein synthesis
3. direct viral damage to host cell (nucleases and proteases)
4. attack by immune system to kill these "virus factories"
169
What are prions?
a protein, that does not contain nucleic acids, but is capable of being infectious even so
170
How are prions spread?
By ingesting prion-containing neurons or lymphocytes
171
How can prions be destroyed if they can survive cooking, digesting, and normal autoclaving?
They must be autoclaved at extremely hot temperatures or be treated with very potent chemicals
172
Why is it so much worse for prions to infect neurons as opposed to lymphocytes?
Because lymphocytes are able to be replaced, but neurons are not.
173
What type of damage do prions cause in neurons?
They induce misfolding of their own kind. They force all of the proteins in the neuron that are the same as it to bend into its shape by attaching to it. Eventually fibrils form when the altered proteins all start to stick together
174
Why are fibrils thought to be lethal in neurons?
Because they could back up protein synthesis.
175
What is the incubation period of prions?
10-20 years
176
What are the names of the different infections caused by prions in various species?
mad cow disease -cow, chronic wasting disease - deer and elk, scrapie - sheep, kuru - cannibals, variant Creutzfeld-Jakob disease - humans.
177
What are some other prion type disease?
Alzheimers, parkinsons, LouGehrigs, and other neurodegenerate diseases
178
What is the mortality rate of prion diseases?
100 %
179
There are _____________ procaryotic cells as eucaryotic cells in the body.
as many
180
Where are normal flora typically found?
on external as well as some internal body surfaces
181
Normal flora do not cause disease as long as...
they are kept in check - by maintaining them in certain locations and quantities
182
What are the 5 locations for normal flora?
1. skin 2. upper respiratory tract 3. mouth 4. large intestine 5. genito-urinary tract
183
What types of microorganisms are normal flora of the skin? How are they kept in check?
Staphylococci and Pseudomonas. By the limited nutrient supply, saltiness, acidity, pH and multiple cellular layer of the skin.
184
What type of microorganism is considered normal flora of the upper respiratory tract? How is it kept in check?
Staphylococci, the cilia in the lining of the trachea sweep it upward so that it does not fall down towards the lungs.
185
What type of microorganism is considered normal flora of the mouth? How is it kept in check?
Streptococci, by the washing action of saliva and skin
186
What type of microorganism is considered normal flora of the large intestine? How is kept in check?
Bacteroides, by specific nutrients available, mucus lining of GI tract,
187
What type of microorganism is considered normal flora of the lower genito-urinary tract? How is kept in check?
Lactobacillus, flow of urine and its low pH.
188
What are 6 things that normal flora may do?
1. help digest complex nutrients
2. secrete vitamines
3. activate drugs
4. influence weight
5. cause allegies
6. compete with pathogenic bacteria
189
What is microbial antagonism?
competition of microorganisms for nutrients
190
What does it mean to say that many normal flora are opportunistic?
That they are potentially pathogenic (able to cause disease) if left unchecked
191
What are three ways that would cause a normal flora to become pathogenic?
1. if there is a rapid increase in population of one type
2. if they escape from their normal habitat ( e.g. getting beneath surface to a more nutritious environment
3. if they expand their habitat ( e.g. nasopharynx to sinuses to middle ear)
192
What is a reservoir?
A continual source of microorganism that provides the microorganism with conditions for growth and a means of spreading
193
What are the 2 types of human reservoirs?
1. people with the infection
| 2. carriers of the infection
194
What does it mean to say that a person is a carrier of an infection?
It means that they have the microorganism as a normal flora so they never get the infection but they are capable of transmitting it.
195
What are examples of infectious diseases transmitted from animal reservoirs?
Rabies, Toxoplasma Gondii ( toxoplasmosis )
196
What are examples of non-living reservoirs?
contaminated water or soil
197
What is an alternating reservoir?
I is when a microorganism grows in one location for awhile, then another
198
What are some examples of nosocomial infections?
pressure sores, UTI's, pneumonia, surgical wounds become infected
199
What are iatrogenic nosocomial infections?
They are infections caused as side-effects of treatment or by the accidents or incompetence of health workers
200
Which microorganisms are usually common opportunists?
S. aureus, E. coli, Pseudomonas, Candida
201
Why are many nosocomial infections antibiotic resistant?
1. gene transfer mechanisms
| 2. heavy antibiotic use in hospitals
202
What does direct contact with a reservoir include?
all kinds of touching, sneezing and coughing
203
What does indirect contact with a reservoir include?
a stationary, non-living intermediate = fomite
204
What is a vehicle?
it is a moving, but inanimate route of microorganism transmission. Such as water, food, or air.
205
What is a vector?
It is a living vehicle, like insects or health care staff.
206
What is the 5 step pattern of infectious diseases?
1. a reservoir is made available
2. MO's onto host
3. MO's into host
4 some attach to host cells
5. the MO's successfully evade the host's defenses and begin the periods of an infectious disease
207
What are the 5 periods of infections disease?
1. incubation
2. prodromal
3. peak disease
4. decline
5. convalescence
208
What is the Threshold of an infectious disease?
The critical population of a microorganism in a host for symptoms to occur.
209
What factors contribute to the time of the incubation period of an infectious disease?
1. the # of MO's
2. the generation time of the MO's
3. the host's resistance
4. the threshold required
210
What is epidemology?
The study which attempts to determine the cause, or etiology, of an infectious disease
211
According to Koch, what are the 3 rules that must be met to claim that a specific MO causes a specific disease
1. correlation between the disease and the specific MO must be found
2. the microorganism should cause the disease when given to a healthy organism
3. a plausible mechanism for how this microorganism causes the disease must be given
212
What are some specific aspects of the microorganism studied in epidemology?
1. the reservoir of the MO
2. its mode of transmission
3. its range or pattern of transmission
4. the extent of its spread
5. how best to vaccinate everyone
213
What is R0?
How many people can each infected person infect
214
How can the route of transmission of an infectious disease be determined?
Interviewing people, watching statistics
215
What types of things fall under the range or pattern of transmission of an infectious disease?
Is there a geographic, demographic, or genetic pattern? (for example)
216
What does R0 have to be in order for an infectious disease to be considered an epidemic?
> 1.5
217
How can the mortality rate of an infectious disease bet determined?
No. deaths / No. hospitalized + No. asymptomatic + No. not hospitalized + No. exposed
218
What are the 5 best ways to block the spread of an infectious disease?
1. vaccinate everyone
2. vaccinate certain people ( contacts of infected person + medical personnel)
3. prophylactic drugs
4. block the route of transmission
5. eliminate the reservoir
