Chapter 1 &2 W1 Flashcards
1
Q
what is a bacterium/bacteria?
A
A prokaryotic organism that is a member of the domain
Bacteria, distinct from archaea and eukaryotes.
-cells that lack a nucleus
2
Q
what is antibiotics?
A
a chemical that kills or slows the growth of bacterial pathogens
3
Q
must of the oxygen we breathe is released by ___?
A
cyanobacteria and algae
4
Q
what is a microbe?
A
a living organism that requires a microscope to be seen- cannot be seen by the human naked eye
-ranges in size from millimetres (mm) down to 0.2 micrometer (um) and verses can sometimes be tenfolds smaller
5
Q
what is a cell?
A
a cell is the smallest unit of life composed of a membrane-enclosed compartment of water solution containing molecules that carry out metabolism
6
Q
what is a pathogen?
A
A bacterial, viral, fungal, protozoan, or helminthic agent of disease; among health professionals, pathogens typically are limited to bacteria, viruses, and fungi
- the causative agent of disease. often referred to as “germs”
- remain the cause of human morality
7
Q
what is a genome?
A
- the total DNA content of an organism
- viral genomes can be RNA or DNA
8
Q
what are prokaryotes?
A
- has no true “nucleus” or nuclear membrane
- prokaryotes include bacteria and archaea
9
Q
what is a eukaryotic?
A
a microbial cell with a nucleus
- includes fungi, protozoa, and algae
- parasitic protozoa and fungi may infect humans
10
Q
what is an algae?
A
A microbial eukaryote that contains chloroplasts and conducts photosynthesis
-overgrowth of algae causes “algal blooms” that poison fish
11
Q
what is a protozoa?
A
a motile heterotrophs (consuming organic food), usually single-celled that is not fungus
12
Q
what is fungi/fungus?
A
heterotrophic organisms that are usually nonmotile and grow by absorbing nutrients from their surroundings. fungi may grow as single cells (yeast) or as filaments (bread mold) or they may for complex structures such as mushrooms.
some fungi cause infections, esp w/ people w/ depressed immune system
13
Q
what is a parasite?
A
Any bacterium, virus, fungus, protozoan (protist), or helminth that colonizes and harms its host; the term commonly refers to protozoa and to invertebrates.
14
Q
what is a virus?
A
a noncellular microbe
-contains genetic material (DNA and RNA) that takes over the metabolism of a cell to generate more virus particles
15
Q
what is archaea?
A
nonbacterial cells that lack a nucleus (prokaryotes)
-does not cause disease
16
Q
what is spontaneous generation?
A
the theory that living microbes can arise spontaneously w/out parental organisms
17
Q
what did Lazzaro Spallanzani do?
A
showed us that microbes arise from preexisting microbes and demonstrated that heat sterilization can prevent microbial growth
18
Q
what did Rober Hooke and Antonio van Leeuwenhoek do?
A
were the first to record observations of microbes through simple microscopes
19
Q
what did Louis Pasteur do?
A
discovered the microbial basis of fermentation. he showed that supplying oxygen dose not enable spontaneous generation
20
Q
what did John Tyndall do?
A
showed us that repeated cycles of heat are necessary to eliminate spores formed by certain kinds of bacteria
21
Q
what is the germ theory of disease?
A
holds that specific diseases are caused by specific kinds of microbes
22
Q
what is chain of infection?
A
-factors that affect the spread of disease, which includes the organisms, reservoir, mode of transmission, and host
23
Q
what is a pure culture?
A
a culture grown from a single “parental” cell
24
Q
what are colonies?
A
-a visible cluster of microbes on a plate, all derived from a single founding microbe.
25
what is a petri dish?
-a round dish with vertical walls covered by an inverted dish of slightly larger diameter. The smaller dish can be filled with a substrate for growing microbes
26
what are the 4 Koch's postulates consist of?
1. the microbe is found in all cases of the disease but is absent from healthy individuals
2. the microbe is isolated from the disease host and grown in pure cultures
3. when the microbe is introduced into a healthy susceptible host, the same disease occurs
4. the same strain of microbe is obtained from the newly diseased host
27
what is an antiseptic agent?
a chemical that kills microbes on living tissues
28
who established the practice of vaccines?
Edward Jenner- inoculation of cowpox to prevent smallpox
29
what is pathogenicity?
the ability of the organism to cause disease
30
what is colonization?
-refers to the ability of the microbe to stay attached to the body surface and replicate.
31
disease occurs when?
pt develops symptoms
32
what is acute infection?
Symptoms develop and resolve rapidly.
| -The common cold, strep throat etc.
33
what is chronic infection?
- involves symptoms that develop gradually and resolve slowly.
- tuberculosis for example
34
what is a primary pathogen?
- likely to cause disease after infection in a healthy host.
- Rapidly reproduce/increase in number
- Moderate to high virulence (severity increases)
35
what is opportunistic pathogens?
-are less likely to cause disease in a healthy host.
| Low virulence
36
what dose virulence mean?
describes the level of harm caused by a pathogen following infection
-virulence can be measured by lethal dose 50% (LD50) or infectious dose (LD50)
37
what is invasion?
the entry of a pathogen into a living cell, where it then lives
38
what is invasiveness?
the ability of a bacterial pathogen to spread rapidly through tissues
39
what is host range?
refers to the animals a pathogen can infect and produce disease in.
-some organisms can infect only one type of host to produce disease
40
what is a narrow host range?
Salmonella enterica serovar Typhi infects humans only.
41
what is a broad host range?
Salmonella enterica serovar Typhimurium infects other animals in addition to humans.
42
what is a disease?
-is a disruption of the normal structure or function of any body part, organ, or system that can be recognized by a characteristic set of symptoms and signs.
43
what is infectious disease?
a disease caused by a pathogen (bacterial, viral, or parasitic) that can be transferred from one host to another
44
what is subacute disease?
infection in which symptoms take longer to develop than in an acute (rapid) infection but arise more quickly than for a chronic infection
ex. subacute bacterial endocarditis (enterococcus faecalis)
45
what is latent infection
type of infection that may occur after an acute episode; the organism is present but symptoms are not; after time, the disease can reappear
ex. cold sores d/t herpesvirus
46
what is focal infection?
initial site of infection, from which organisms can travel via the bloodstream to another area of the body
ex. boils (staphylococcus aureus)
47
what is disseminated infection?
infection caused by organisms traveling from a focal infection; when affecting several organ system, it is called "systemic infection"
ex. tularemia (Francisella tularensis)
48
what is metastatic infection?
site of infection resulting from dissemination
| ex. blastomycosis, fungal infection of the lung; can disseminate to form abscess in the extremities (arms/legs)
49
what is bactermia?
presence of bacteria in blood; usually transient, little, or no replication
ex. during dental procedures (streptococcus mutans)
50
what is septicemia?
presence and replication of bacteria in the blood (blood infection)
ex. plague (Yersinia pestis)
51
what is viremia?
presence of viruses in the blood
| ex. HIV
52
what is toxemia?
presence of toxin in the blood
| ex. dither, toxic shock syndrome`
53
what is primary infection?
infection in a previously healthy individual
| ex. syphilis (treponema pallidum)
54
what is secondary infection?
infection that follows a primary infection; damaged tissue (e.g., lung) is more susceptible to infection by a different organism
ex. bacterial infection following viral influenza (haemophilius influenza)
55
what is mixed infection?
infection caused by two or more pathogens
| ex. appendicits (bacteroides fragilis and escherichia cells)
56
what is iatrogenic infection?
infection transmitted from a HCP to a pt
| ex. some septicemias (staphylococcus aureus)
57
what is nosocomial infection?
infection acquired during hospital stay
| ex. MRSA (methicillin- resistant staphyoloccous aureus)
58
what is community acquire infection?
infection acquired by the community not the hospital
| ex. some MRSA strains, flu, HIV
59
what is a symptom?
are experienced by the person (subjective indicator of disease).
– Pain
– Fatigue
-dizziness
60
what is a sign?
can be observed by examination (objective marker of
disease).
– Fluid-filled rash
– Fever of 102°F
61
what is a syndrome?
a collection of signs and symptoms that occur together and collectively characterize a condition
62
what is a sequelae?
pathological consequences after disease resolves
ex. dysphagia after stroke, immune response to strep throat can cause heart damage weeks after the infection has resolved
63
what is morbidity?
rate of illness d/t disease
| -how many people are sick from an infectious disease
64
what is morality?
rate of death d/t disease
65
what is direct contact?
intimate interaction between two people
| ex. touching, kissing, sex (mono, gonorrhoea) or aerosolization (sneeze)
66
what is indirect contact or transmission?
transmission of an infectious agent from one person to another by an insect vector or an inanimate object
ex. mosquito (malaria), sharing a spoon (strep infection)
67
what is vehicle transmission (fomities)
form of indirect transmission whereby an infectious agent is transferred to an inanimate object (fomite) by one person touching it and then transferred to another person touching the same object, or by ingesting contaminated food or water, or by inhaling the agent in air
-ex. doorknobs, shared utensil (influenza, strep)
68
what dose vehicle mean?
means of pathogen transmission as by air, food, or liqud
| ex. air (anthrax), food (salmonella), water (leptospira)
69
what does vector mean?
living carrier of infectious organisms
| ex. mosquitoes (west nile), fleas (yersinia pests), body lice (rickettisa)
70
what does aerosol mean?
organisms in air suspension
| ex. sneezing (rhinovirus) air-conditioning or heating (legionella) water from a shower (mycobacterium avlium)
71
what is a reservoir?
nonhuman animal, plant, human or environment that can harbour the organism; a reservoir may or may not exhibit disease
ex.cattle (ecoli), horses (west nile verses) alfalfa sprouts (salmonella)
72
fecal-oral route
pathogen exists the body in feces, which contaminates food, water, or fomite; pathogen is introduced into a new host by ingestion
ex. shigella, e.coli, salmonella, rotavirus
73
respiratory route transmission?
pathogens enters the body through breathing
| ex. influenza, streptococcus pneumoniae
74
what is urogenital route?
pathogen enters the body through Aretha or vagina
| ex. urinary tract infection (non sexual) syphillis (sexual contact)
75
what is parental route transmission?
pathogens enter the body through insect bite or needle injection
ex. malaria, HIV (AIDS)
76
what is an endemic?
disease (humans) is present in specific geographic location; pathogen is usually harboured in an animal or human reservoir
ex. Lyme disease, common cold
77
what is epidemic?
number of disease that exceed the endemic level
| ex. influenza, plaque
78
what is a pandemic LOL
worldwide epidemic
| ex. covid, influenza, acquired immunodeficiency syndrome (AIDS)
79
what is horizontal/direct transmission?
ccurs when the infectious agent is transferred from one person or animal to the next
80
what is vertical transmission?
occurs when the infectious agent is transferred from parent to offspring
81
what is asymptomatic carrier?
harbors the potential disease agent but does not have the disease.
• Neisseria meningitidis is an important cause of meningitis.
– It has no animal reservoir and is maintained in the human population by asymptomatic hosts.
82
what are zoonotic disease?
are infections of animals that can be transmitted to humans
- Pathogens may or may not cause the animal reservoir to have a disease.
- Transmission may be direct or indirect “spillovers” from animal to human
83
what is lyme disease?
Pathogen does not cause disease in the animal host but does cause disease when bacteria “spill over” to humans
84
what is ebola?
Virus does cause disease in the animal host and also in humans
85
what is BSL1 (biosafety level)?
low risk; basic precautions- have little to no pathogenic potential and require the lowest level of containment
- basic sterile technique
- no mouth pepetting
ex. e-coil k-12
86
what is BSL2 (biosafety level)?
human pathogens causing mild disease; barrier
precautions
-moderate potential hazard
-limited access to lab; biohazard safety cabinets used
-laminar flow hoods are required
-hepatitis vaccination recommended
ex. chlamydia, salmonella
87
what is BSL3 (biosafety level)?
human pathogens causing serious illness; separate rooms, work done in a biosafety cabinet (BSC)
agents may cause disease by inhalation route
ventilation providing directional airflow into room, exhaust air directed outdoors; restricted access to lab (no unauthorized persons)
-negative pressure rooms
ex. SARA, tuberculosis
88
what is BSL4 (biosafety level)?
high-virulence pathogens where exposure can be lethal; separate facilities
- dangerous and exotic pathogens with high risk of aerosol transmission
- must be completely isolated from other areas
- lab personnel must wear positive pressure lab suits connected to a separate air supply
ex. ebola, tick-borne encephalitis viruses
89
what are the standard precautions designed by the CDC to protect medical personnels?
1. Perform proper hand hygiene.
2. Use personal protective equipment (PPE).
3. Maintain respiratory and coughing hygiene.
4. Use safe injection practices.
5. Handle sharps safely.
6. Practice patient isolation precautions.
7. Sterilize instruments and devices.
8. Clean and disinfect environmental surfaces.
90
what is an emerging disease?
are diseases that have not previously been recognized and are the result of either newly evolved organisms or organisms that have made the “leap” from animal to human host.
91
what is the incubation period?
time after a microbe first infects a person through a portal of entry but before the first sign of disease
- depending on the disease pts may be contagious even though them appear healthy
- during this period the microbe is trying to replicate to higher and high numbers -like using a thick capsule coat to hide from the host's immune system
92
what is the prodromal phase?
short and sometimes not apparent
- involves vague symptoms like headache or malaise, that serve as a warning of more serious symptoms to come
- can spend microbe to others
93
what is the illness phase?
begins w/ typical symptoms and signs of the disease appear
- the point at which disease symptoms are most severe is called acme
- the battle between microbe and host is at its peak during this time
- fever is common here
94
max fever an adult can handle?
39.4 (103F) is the safe limit
95
max fever a child can hold? (safe)
41 (106F)
96
what is the decline phase?
begins as the symptoms subside
- host defenses have won
- fever starts to go down "breaking a fever" -blood vessels will dilate to lose heat (vasodilation) and pt will start to sweat
97
what is the convalescene period?
-period after symptoms have disappeared and the pt begins to recover normal health
98
what is insect vector?
microbes can be transmitted from animal to animal (and to humans) by insect vector
99
what is transplacental transmission?
mom can transmit organism to her fetus through the placenta
| =infected child can be delivered w/ serious congenital deformities, even can cause stillborn
100
what is reemerging disease?
are diseases that have existed but are exhibiting a recent increase in incidence or geographic location.
