Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Medical Microbiology > Infection, Infectious Disease, and Epidemiology > Flashcards

Infection, Infectious Disease, and Epidemiology Flashcards

Chapter 14

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards USMLE® Step 1 flashcards
1
Q

What is the word for members of a symbiotic relationship?

A

Symbionts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is symbiosis?

A

The relationship between organisms (or microorganisms)”living together”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 4 symbiotic relationships?

A

Mutualism, Commensalism, Amensalism, & Parasitism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

In what type of symbiotic relationship do both symbionts benefit from their interaction?

A

Mutualism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

True or False: Symbionts in a mutualism interaction require each other to survive. Why or why not?

A

False. Despite the benefits, not every mutualistic relationship is necessary for either symbionts survival.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Explain Commensalism

A

One symbiont benefits from the relationship without significantly affecting the other symbiont

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is it difficult to prove an absolute example of commensalism?

A

Because there may be unobserved benefits experienced by one of the symbionts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is Amensalism?

A

One symbiont is harmed by the second symbiont, but the second symbiont is not harmed or helped by the first symbiont.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain Parasitism

A

Symbiotic relationship where a parasite benefits from its host while causing harm to said host. The harm sustained by the host can vary greatly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a parasite that causes disease called?

A

A pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why might there be a coevolution towards commensalism/mutualism from an originally parasitic relationship?

A

Because there are parasites that allow their host to survive, making it more likely to spread. Similarly, some hosts better tolerate a parasite and are more likely to reproduce.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define Bioterrorism

A

The deliberate release of viruses, bacteria, or other germs to cause illness or death.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What characterizes Axenic Environments in our body?

A

places free of any microbes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the human microbiome made of?

A

Microbes that colonized our body without causing disease (normally)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

List 3 other ways to refer to the body’s microbiome

A

Normal Microbiota, Normal Flora, or Indigenous Microbiota

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What 2 main types of organisms make up the microbiome?

A

Resident microbiota & transient microbiota

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where is resident microbiota found?

A

On the skin, on mucous membranes of digestive tract, upper respiratory tract, distal urethra, and vagina.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does it mean that most resident microbiota are commensal?

A

It means that they feed on excreted cellular waste/dead cells without harming a person

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What layers of the skin are Axenic?

A

dermis & hypodermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Explain transient microbiota

A

Microbes that remain in the body for a few hours, days, before peacing out.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why can’t transient microbes persist in the body even though they are found in many of the same locations as resident microbes? (3 reasons)

A

Because of competition from other microorganisms; from being eliminated by the body’s defenses; or chemical/physical changes in the body that dislodges them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why don’t we develop a microbiome in the womb?

A

Because you are surrounded by an amniotic membrane/fluid that keeps microogranisms at bay. And the mother’s uterus also grants additional protection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When do we begin to develop a microbiome?

A

When the amniotic membrane is ruptured during birth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

When is most of our resident microbiota established?

A

During the first months of life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are 4 ways normal microbiota can become opportunistic pathogens?

A
  1. From normal microbiota being introduced into an unusual site in the body that they do not typically inhabit
  2. From immune suppression
  3. From changes in the normal microbiome
  4. From stressful conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is microbial antagonism/competition?

A

The situation in which normal microbiota function in such a way as to make it less likely for arriving pathogens to compete well enough to produce disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What sort of stressful conditions can lead to opportunistic pathogens?

A

Hormonal changes, unresolved emotional stress, abrupt diet changes, or exposure to a very large number of pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What do we call living or nonliving sources of infectious diseases?

A

Reservoirs of infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the 3 reservoirs of infection?

A
  1. Animal (or zoonotic)
  2. Human
  3. Nonliving
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What makes it more likely for a pathogen to affect human health that is originally zoonotic?

A

The more similar the animals physiology is to human physiology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are zoonoses?

A

Diseases that spread naturally from animals hosts to humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

List an example of a zoonoses

A

Anthrax, bubonic plague, rabies, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Why is it difficult to eradicate human infections with zoonoses?

A

Because of the extensive animal reservoirs involved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Why can it be challenging to control the spread of disease to humans from animals?

A

Sometimes the contact between humans and animals is extensive, making it more difficult and costly to control disease spread. Larger animal reservoirs also makes it difficult as more animals and animal types are infected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are sylvatic animals?

A

wild animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

True or false: it is no more difficult to control the spread of disease to humans from animals when both sylvatic and domesticated animals are reservoirs.

A

False. Both sylvatic and domesticated animals serving as a reservoir make it more difficult to control the spread of disease. Although sometimes you can take precautions like vaccinations to prevent domesticated pets from being infected by sylvatic animals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Why are humans usually dead-end hosts for zoonotic pathogens?

A

Because humans are not the optimal reservoir to reinfect animal hosts; zoonoses transmission favour movement from animals to humans but not the other way around.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What makes human reservoirs difficult to identify as infectious at times?

A

The fact that some humans can act as carriers for an infection, without ever getting sick themselves.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are examples of nonliving reservoirs?

A

Soil, water, food, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Define contamination

A

the presence of microbes in/on the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are 3 potential outcomes of contamination?

A
  1. Microbes remain and become part of resident microbiota
  2. Microbes remain for a short amount of time as part of transient microbiota
  3. Microbes invade and multiple within the body, leading to infection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

True or False: An infection results in disease

A

False. Infections may or may not adversely affect the body, so they do not always result in disease.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are portals of entry?

A

sites where pathogens can enter the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What are the 3 major portals of entry types?

A
  1. Skin
  2. Mucous membranes
  3. Placenta
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Why is the parenteral route not considered a portal of entry for pathogens?

A

Because it is not a proper portal, but rather a way for pathogens to circumvent the other usual portals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

List some portals of entry

A

the skin, placenta, conjunctiva, & mucous membranes of the respiratory, gastrointestinal, urinary, & reproductive tracts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the parenteral route of infection?

A

A puncture through the skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

How can microbes get past the skin barrier if it still appears to be intact?

A

Via hair follicles or sweat gland ducts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What lines every body cavity that is open to the outside world?

A

Mucous membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is the conjunctiva?

A

the thin membrane covering the surface of the eyeball & underside of each eyelid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Why do microbes typically find mucous membranes to be easier portals of entry than the skin?

A

Unlike skin, the mucous membrane is thin, moist, and warm in comparison.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What is the most frequently used portal of entry?

A

Respiratory tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

How do viruses enter the respiratory tract via the eyes?

A

Viruses can be introduced to the conjunctiva by contaminated fingers. The virus can then be washed into the nasal cavity with tears.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Microbes that can infect via the gastrointestinal mucous membrane are typically able to survive what?

A

The acidic pH of the stomach & the digestive juices of the intestinal tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Why is the placenta typically effective in barring most pathogens from a fetus?

A

Because, despite the close contact of the wall of the mother’s uterus and the placenta, the two blood supplies do not contact each other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What must symbionts do after they enter the body to successfully establish colonies?

A

Adhere to cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is adhesion (or attachment)?

A

The process by which microorganisms attach themselves to cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

How do pathogens accomplish adhesion? Explan.

A

Through adhesion factors; specialized structures or attachment molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Give an example of how adhesion via attachment molecules is possible, and what microbes do this

A

Viruses and some bacteria have ligands that enable them to bind to complementary receptors on host cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What are ligands?

A

lipoproteins or glycoproteins on the surface of viruses/bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Bacterial Ligands are called what?

A

Adhesins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Virus Ligands are called what?

A

Attachment proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What can be done to ligands to prevent infection?

A

Changing them or blocking them so that ligands on microbes cannot adhere to host cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What interaction can determine the specificity of pathogens for particular hosts?

A

The interaction of adhesins on microbes and host cell receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

How do some pathogens adapt to help them evade the immune system?

A

By having more than one type of adhesin or the ability to change their adhesins over time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Define avirulent in the context of microbes.

A

Microbes that are harmless because of mutations or physical/chemical agents (such as a vaccine) that have stopped that microbes ability to make ligands.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What is biofilm?

A

A community of microbes growing on a surface within a host, but that do not actually attach to host cells directly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What is dental plaque an example of?

A

Biofilm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Define Disease

A

An adverse internal condition that interferes with normal bodily functioning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What is morbidity?

A

any change from a state of health

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Define syndrome

A

a group of symptoms and signs that collectively characterize a certain disease or abnormal condition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What is another word for asymptomatic infections?

A

Subclinical infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What is etiology?

A

the study of the cause of a disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

List 2 microbiologists that helped propose the germ theory of disease?

A

Louis Pasteur & Robert Koch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What is the germ theory of disease?

A

Theory that disease is caused by infections of pathogenic microorganisms (referred to as germs at the time)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What must a scientist satisfy to prove that a given infectious agent causes a given disease?

A

They must satisfy Koch’s Postulates in order

74
Q

List Koch’s Postulates

A
  1. Suspected agent must be present in every case of the disease
  2. agent must be isolated and grown in pure culture
  3. cultured agent must cause the disease when inoculated into a healthy, susceptible experimental host
  4. Same agent should be found in the diseased experimental host
75
Q

What are some exceptions to Koch’s 2nd postulate?

A

Pathogens that have not been able to be cultured in a laboratory. I.e mycobacterium leprae which causes leprosy.

76
Q

Why might it be difficult to attribute a singular pathogen to a disease?

A

Because some diseases are a result of a combination of pathogens and cofactors; so the pathogen alone my be unable to cause disease

77
Q

What is an important ethical consideration of Koch’s postulates in regards to the 3rd postulate?

A

It is not ethical to inoculate a healthy susceptible host for diseases/pathogens that only occur in humans

78
Q

Why is it not always possible to establish a single cause for some infectious diseases? Give an example

A

Because some diseases, such as pneumonia, meningitis, hepatitis, refer to conditions that can be caused by more than one pathogen (different pathogens causing the same disease)

79
Q

How can we “know” the causative agent of a disease if we cannot apply Koch’s postulates?

A

Via epidemiological studies

80
Q

Define pathogenicity

A

The ability of an agent to cause noticeable disease

81
Q

Define virulence

A
82
Q

What are virulence factors?

A
83
Q

What are the 5 virulence factors discussed in the textbook?

A
  1. adhesion factors
  2. biofilm formation
  3. extracellular enzymes
  4. toxins
  5. antiphagocytic factors
84
Q

In the context of pathogens, what are extracellular enzymes/what do they do?

A

Enzymes that are secreted by the pathogen to dissolve structural chemicals in the body to maintain infection, invade further, and avoid the bodies defenses

85
Q

What does coagulase do? How does this impact bacteria?

A

Causes blood proteins to clot, providing a “hiding place” for bacteria within a clot

86
Q

What are toxins?

A

chemicals that harm tissues or trigger host immune responses that cause damage

87
Q

What are exotoxins?

A

toxins released by microorganisms that destroy host cells or interfere with metabolism

88
Q

What are the 3 types of exotoxins?

A
  1. Cytotoxins
  2. Neurotoxins
  3. Enterotoxins
89
Q

What exotoxin kills host cells in general or affects their function?

A

Cytotoxins

90
Q

Explain neurotoxins

A

Exotoxins that specifically interfere with nerve cell function

91
Q

Explain enterotoxins

A

Exotoxins that affect the cells lining the gastrointestinal tract

92
Q

How does the body protect itself from exotoxins?

A

With protective molecules called antibodies that bind to specific toxins & neutralize them

93
Q

Explain antitoxins

A

antibodies against toxins

94
Q

How can health care workers stimulate the production of antitoxins?

A

By administering immunizations composed of toxoids, which are treated to be non-toxic but still capable of stimulating the production of antibodies

95
Q

What do endotoxins come from? What is the specific structure that is poisonous?

A

They come from Gram-negative bacteria. Lipopolysaccharides (LPS) in the outer membrane are released upon cell death, exposing the poisonous lipid A of LPS.

96
Q

Is Lipid A the same between bacterias?

A

No. It varies between gram-negative bacteria and among bacterial strains

97
Q

Is lipid A a single molecular structure?

A

No. It is an array of similar lipid molecules.

98
Q

How are endotoxins released?

A

When gram-negative bacteria divide, die naturally, or are digested by phagocytic cells (like macrophages)

99
Q

What stimulates the body to release chemicals that cause fever, inflammation, hemorrhaging, shock, and blood coagulation when released by gram-negative bacteria?

A

The endotoxin lipid A

100
Q

Are gram-negative pathogens life threatening?

A

They are often life threatening, yes, because the endotoxin released from dead cells can produce serious systemic effects in a host

101
Q

For which toxin is toxoid formations for immunization feasible?

A

Exotoxins; not feasible for endotoxins

102
Q

What bodily structures attempt to limit the extent and duration of infections? How?

A

Phagocytic cells like white blood cells (macrophages) engulf invading pathogens and remove them

103
Q

How are the capsules of pathogenic bacteria effective virulence factors?

A

They are effective because they are composed of chemicals normally found in the body, so they do not stimulate an immune response

104
Q

Besides presenting a familiar chemical structure, how else do bacterial capsules effectively evade phagocytes?

A

The bacterial capsules are often slippery, making it difficult for phagocytes pseudopods to grip the capsule and phagocytize them

105
Q

How do some bacteria survive inside phagocytes?

A

By preventing the fusion of lysosomes with phagocytic vesicles

106
Q

What are the 5 stages of the disease process?

A
  1. Incubation Period
  2. Prodromal Period
  3. Illness
  4. Decline
  5. Convalescence
107
Q

True or false; all infectious diseases follow the 5 step disease process

A

False

108
Q

What is the incubation period of an infectious disease?

A

The time between infection and the first occurence of symptoms or signs of disease

109
Q

Is the incubation period of a disease always the same?

A

Not always. Some have typical incubation periods whereas others vary considerably due to a multitude of factors, such as the strength of the hosts immune system.

110
Q

What is the prodromal period?

A

A short period of time characterized by mild symptoms that precede illness.

111
Q

What is the most severe stage of an infectious disease?

A

illness

112
Q

Will a person’s immune system have started responding to a pathogen during the illness stage?

A

Not fully

113
Q

Describe the Decline stage of disease

A

Period in which the body gradually returns to normal as the immune response and/or medical treatment destroys pathogens

114
Q

In what stage of the disease process does immune response and its products peak?

A

During the stage of Decline

115
Q

What is the convalescence stage of disease?

A

The point in which a person recovers from illness; tissues are repaired & return to normal

116
Q

What does the length of the convalescent period depend on?

A

The amount of damage, the nature of the pathogen, the site of infection, and the overall health of the person

117
Q

At what stages of disease are people infectious?

A

At likely every stage

118
Q

At what stages of disease are people often unaware that they may be infectious?

A

During incubation and convalescence; just because you are feeling better does not mean you are no longer infectious.

119
Q

How do pathogens typically exit hosts?

A

in materials secreted or excreted by the body

120
Q

What are the 3 arbitrary categories of transmission?

A

Contact, vehicle, and vector transmission

121
Q

Explain direct transmission

A

the spread of pathogens from one host to another by direct or indirect contact, or respiratory droplets

122
Q

Explain Direct contact transmission

A

person-to-person spread via bodily contact

123
Q

Transfer of pathogens from an infected mother to a developing baby across the placenta is what kind of transmission?

A

Direct contact transmission

124
Q

What sort of transmission involves any form of touching, intercourse, scratching, etc.?

A

Direct contact transmission

125
Q

Explain indirect contact transmission

A

the spread of pathogens via fomites

126
Q

Define fomites

A

inanimate objects that can carry and transmit a pathogen between hosts

127
Q

Contaminated needles represent what kind of transmission?

A

Indirect contact transmission via fomites

128
Q

Explain droplet transmission

A

A type of contact transmission in which pathogens are transmitted within droplet nuclei when exhaling, coughing, and sneezing

129
Q

What are droplet nuclei?

A

droplets of mucus

130
Q

What distinguishes droplet transmission from airborne transmission?

A

droplet transmission occurs when pathogens travel less than a meter via respiratory droplets; if they travel more than 1 meter, it is considered airborne transmission

131
Q

What type of transmission is characterized by the spread of pathogens via air, drinking water, food, and bodily fluids handled outside the body?

A

Vehicle transmission

132
Q

Explain airborne transmission

A

the spread of pathogens beyond 1 meter to a new host via an aerosol

133
Q

Actions such as sweeping, changing clothes, flaming inoculating loops in a lab and air-conditioning systems can results in what sort of transmission?

A

Airborne transmission

134
Q

What can transmit staphylococcus, streptococcus, and hantavirus?

A

Dust particles

135
Q

How is the measles virus and tuberculosis bacilli transmitted?

A

airborne droplets

136
Q

Explain foodborne transmission

A

pathogens in and on foods that are inadequately processed, undercooked, or poorly refrigerated leading to transmission of pathogens

137
Q

Arthropods that transmit disease are called what?

A

Vectors

138
Q

What are the two types of vector transmission?

A

Biological and Mechanical

139
Q

What is the difference between biological and mechanical vectors?

A

Both transmit pathogens but biological vectors can also be hosts for the multiplication of a pathogen, whereas mechanical vectors are not needed to host pathogens

140
Q

What are the 4 vehicle transmission types?

A
  1. Airborne
  2. Foodborne
  3. Waterborne
  4. Bodily fluid
141
Q

Classification of disease in which disease develops rapidly but last a short time

A

Acute disease

142
Q

Classification of disease in which disease develops more slowly and usually with less severe symptoms

A

Chronic disease

143
Q

What is the classification of disease that has durations & severities somewhere between acute and chronic?

A

Subacute disease

144
Q

Explain Latent Diseases

A

Diseases in which a pathogen remains inactive for a long time before becoming active

145
Q

What are the classifications of disease according to longevity & severity?

A
  1. Acute
  2. Subacute
  3. Chronic
  4. Latent
146
Q

What is a communicable disease?

A

An infectious disease that comes from another infected host, either directly or indirectly

147
Q

How do we refer to a communicable disease that is easily transmitted between hosts?

A

Contagious disease

148
Q

Explain noncommunicable diseases

A

Diseases that are not spread from one host to another but arise either from outside a host or the resident microbiome

149
Q

What is a local infection?

A

an infection confined to a small region of a body

150
Q

What do we call a widespread infection in many systems of the body that often travels in the blood or lymph?

A

Systemic infection

151
Q

What is a focal infection?

A

an infection site that serves as a source of pathogens for infections at other sites in the body

152
Q

What is a primary infection?

A

Initial infection within a person

153
Q

What is a secondary infection?

A

Infections that follow a primary infection; often by opportunistic pathogens

154
Q

What is epidemiology?

A

The study of the distribution and determinants of disease & death within human populations

155
Q

What is incidence?

A

The number of new cases of a disease in a certain area/population during a given time period

156
Q

What is prevalence?

A

The total number of cases (new and old) in a given area/population during a given period of time

157
Q

What is an endemic?

A

a disease that occurs continually (at moderately regular intervals) at a stable incidence within a population or geographical area

158
Q

When do we consider a disease to be sporadic?

A

When only a few scattered cases occur within an area/population

159
Q

What is an epidemic?

A

When a disease occurs at a higher frequency than is usual for an area/population

160
Q

What is a common misconception about what can be considered an epidemic?

A

That a disease must infect thousands or millions to be considered an epidemic

161
Q

What do we call an epidemic that occurs simultaneously on more than one continent?

A

A pandemic

162
Q

What are the 3 approaches to epidemiology?

A
  1. Descriptive
  2. Analytical
  3. Experimental
163
Q

What is an index case?

A

The first case of a disease in a given area or population

164
Q

Why might it be difficult or even impossible to identify an index case?

A

Because sometimes the index case has recovered already, moved, or even died.

165
Q

The time course and chains of transmission of a disease are important to what type of epi?

A

Descriptive Epi

166
Q

When was the earliest descriptive epi study, who conducted it and why?

A

In 1854 by John Snow who studied a cholera outbreak in London.

167
Q

When it is not ethical to apply Koch’s postulates what else might we use?

A

Analytical Epi

168
Q

Analytical epi is used to investigate a disease in detail to determine what? (3 things)

A
  1. The probable cause of a disease
  2. The mode of transmission
  3. Possible preventions of the disease
169
Q

What does experimental epi do?

A

Test a hypothesis concerning the cause of a disease

170
Q

What are healthcare-associated infections? (HAIs)

A

Infections acquired by patients/health care workers while they are in health care facilities

171
Q

What is another word for healthcare-associated infections?

A

Nosocomial infections

172
Q

What are exogenous HAIs?

A

infections caused by pathogens acquired from a health care environment

173
Q

What are endogenous HAIs?

A

Infections that arise from normal microbiota within a patient which become pathogenic because of factors within the health care setting

174
Q

Opportunistic pathogens caused by hospital related care such as medical treatments are referred to as what?

A

Endogenous HAIs

175
Q

What are iatrogenic infections?

A

Subset of HAIs caused by modern medical procedures

176
Q

What are some procedures that can lead to iatrogenic infections?

A

Surgery, catheters, invasive diagnostic procedures, etc.

177
Q

What are superinfections and what causes them?

A

Superinfections result from antimicrobial drugs that inhibit some resident microbiota, allowing others to thrive due to lack of competition

178
Q

C Diff (Clostridium Difficile) is an example of what?

A

A superinfection

179
Q

What are 3 factors influencing HAIs?

A
  1. Microorganisms present in hospital environment
  2. Immunocompromised persons
    3.Transmission of pathogens between staff and patients
180
Q

What is the ssingle most effective way to reduce HAIs?

A

Effective hand washing by medical and support staff

181
Q

What 2 processes are used to reduce the number of pathogens in water supplies?

A

Filtration and chlorination

182
Q

What sort of diseases are particularly difficult for public health officials to control?

A

Diseases that are transmitted sexually and through the air

183
Q

Give an example of mutualism

A

bacteria in the human colon

184
Q

Give an example of amensalism

A

The fungus penicillium inhibits nearby bacteria but is not affected by the bacteria

185
Q

Give an example of parasitism

A

Tuberculosis bacteria in the human lung

186
Q

Give an example of commensalism

A

Hair follicle mites that live on human skin

Medical Microbiology (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions