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Flashcards in Exam 4 Deck (296):
1

______ is the microbe establishing itself on the host. When a pathogen colonizes, it is called a _____. Why is this?

-Colonization
-Infection
-The pathogen has a parasitic relationship with the host

2

A _____ infection has mild symptoms and may even go unnoticed. However, A _____ disease has noticeable impairment with symptoms and signs.

-Subclinical
-Infectious

3

What is the difference between signs and symptoms? Give some examples.

-Signs: Objective evidence such as rash, swelling, blood count, or fever
-Symptoms: Subjective effects such as pain, nausea, and soreness

4

A ____ infection is the first one to occur. A _____ infection takes advantage of this and is an additional infection that occurs during or after treatment of the first infection due to a weakened ______ ______.

-Primary
-Secondary
-immune system

5

An example of a secondary infection is getting _____ after an upper respiratory infection.

-pneumonia

6

______ is the mechanism by which disease is caused.

Pathogenicity

7

A _____ pathogen is a microbe or virus that can overcome the immune system and cause disease in an otherwise healthy individual.

-Primary

8

A _____ pathogen is one that causes disease only when the body's immune defenses are compromised. These pathogens are often part of the body's ____ ____.

-Opportunistic
-Normal Flora

9

Give two examples of opportunistic pathogens.

1. Candida Albicans causing vulvovaginitis
2. Streptococcus Pneumonia

10

______ is the degree of pathogenicity of a microorganism. It is determined by its _____ _____.

-Virulence
-Virulence Factors

11

______ _____ are molecules that a microorganism produces that cause disease or illness.

-Virulence Factors

12

The _____ _____ is the number of microbes needed to establish infection. The ______ is the number of cells that infects 50% of the population.

-Infectious Dose
-ID50

13

Compare the ID50's of Shigellosis and Salmonellosis.

-Shigellosis is highly virulent with a low ID50 and only needs about 10-100 microbes to cause disease
-Salmonellosis needs near 1 million microbes to cause disease

14

The smaller the ID50, the _____ the incubation period.

Shorter

15

Name 2 host-related changes or factors that can lead to changes in the composition of the normal microbiota

1.Antibiotics
2.Variation of diet

16

Name 2 host-related changes or factors that can affect the length of the incubation period.

1. Age
2. Host condition

17

Name 2 microbe-related changes or factors that can affect the length of the incubation period.

1. ID50
2. Pathogen growth rate

18

What are the stages of infection? What is the prodromal phase and where does it fit in the stages of infection?

-Incubation --> illness --> Convalescence
-The prodromal phase has vague symptoms and no signs, and would be in between incubation and illness.

19

The ___ ____ is the time between infection and onset of the illness. How long can it last? What does it depend on?

-Incubation period
-A few days (common cold) to years (leprosy)
-Age, growth rate of the pathogen, host's physical condition, infectious dose

20

In the _____ period of infection, signs and symptoms of the disease are experiences.

Illness

21

The _____ period of infection has vague symptoms and is a transition period before the actual illness kicks in. It is before the ____ period.

-Prodromal
-Illness

22

The _____ period of infection includes recuperation and recovery from the infection.

-Convalescence

23

Which stage of disease are individual's contagious?

They can be contagious during any period, signs and symptoms may not be happening

24

_____ are individuals who harbor and spread an infectious agent for long periods of time in absence of signs or symptoms. A good example of this is ______.

-Carriers
-STD's

25

In _____ infections, symptoms develop quickly and last a short time. What is an example of this?

-Acute
-Strep Throat

26

_____ infections develop slowly and last for months or years.

Chronic

27

______ infections are never completely eliminated. The microbe will exist in host tissues without causing any symptoms; it is ____. What are two examples of this?

-Latent
-Dormant
-Shingles and Herpes

28

What can cause a recurrence of a latent infection?

Weakening of the immune system

29

A _____ infection occurs when the microbe is limited to a small area. What is an example of this?

-Localized
-Boils caused by S. Aureus

30

In a ____ infection, the agent is spread throughout the body. What is an example of this?

-Systemic
-Measles caused by the measles virus

31

What does the suffix -emia mean?

In the blood

32

What are the five stages for establishing an infection?

1. Adherence
2. Colonization
3. Delivering effector proteins to the host cell
4. Avoiding host defenses
5. Causing damage to the host

33

When establishing an infection, what happens during adherence?

Adhesins attach to a host cell receptor to avoid the first line of defense

34

Where are adhesins located and what do they do?

-Located on the tips of pili, capsules, or cell wall
-Exploit the host cell receptor for adherence

35

When establishing an infection, what happens during colonization?

-Growth of microorganism in biofilms
-Competing with the normal flora
- Tolerating and overcoming the host defenses

36

What five things can microorganisms do to colonize the host?

1. Produce siderophores to bind iron
2. Strip the iron bound to lactoferrin
3. Avoid host IgA by pili turnover
4. Antigenic variation
5. IgA protease synthesis that will digest IgA

37

What is pili turnover and how does it help the microbe colonize?

-The microorganism their pili and produces new pili to shed any IgA antibodies

38

What is antigenic variation and how does it help the microbe colonize?

-The microbe will change the structure of pili to avoid specific antibodies. The antibodies will no longer recognize the new pili.

39

Adhesins and siderophores are _____ _____ used to ______ the host and establish infection.

-Virulence factors
-Colonize

40

For a microorganism to establish infection in the host, there are several types of _____ ____ that deliver _____ _____.

-Secretion systems
-Effector proteins

41

Give an example of a secretion system used by microorganisms to establish infection.

-Type III secretion system, also called injectisome
-A syringe-like structure that injects effector proteins into the the host cell
-The effector proteins cause the host cell to take the microorganism in via endocytosis

42

For invasion of a pathogen, the pathogen has to breach _____ _____. For example, _____ can block up to 80% of pathogens.

-Anatomical barriers
-Skin

43

What two ways can invasion of a pathogen occur?

-Penetrating the skin after an injury
-Penetrating a mucous membrane

44

What are two ways a microorganism can penetrate a mucous membrane during invasion?

1. Direct uptake by cells
2. Exploiting antigen-sampling processes

45

Give an example of a microorganism that uses direct uptake by cells to penetrate a mucous membrane during the invasion process.

-Salmonella adheres to a host cell and uses a type III secretion system to send effector proteins into the host cell
-The effector proteins cause membrane ruffling, which allows for bacteria uptake

46

What does membrane ruffling of a host cell involve?

Actin rearrangement

47

Give an example of a microorganism that exploits the antigen-sampling processes of host cells to penetrate a mucous membrane during the invasion process.

-Shigella uses MALT to cross the membrane through specialized MALT cells called M cells, which sample contents of the intestinal lumen
-When they are through the M cells, they use a Type III secretion system to induce uptake into epithelial cells
-In epithelial cells, they can cause host actin to polymerize, which can propel them to neighboring cells

48

What are four ways microbes have evolved mechanisms to avoid the host's defense?

1. Hiding within a host cell
2. Avoiding destruction by phagocytosis
3. Avoiding killing by complement system proteins
4. Avoiding antibodies

49

How does hiding within a host cells allow the pathogen to avoid host defenses?

It allows for avoidance of complement proteins, phagocytes, and antibodies

50

Give an example of a microorganism that avoids host defenses by hiding within a host cell. What does this allow it to do?

-Shigella is directly transferred from intestinal epithelial cells to adjacent cells by causing actin polymerization
-Because of this, Shigella can multiply in the host and cause tissue destruction, which causes diarrhea, fever, nausea, and vomiting

51

What three ways can a pathogen avoid destruction by phagocytes in an effort to avoid the host defenses?

1. Prevent encounters with phagocytes
2. Avoid recognition and attachment, thereby avoiding opsonization
3. Surviving withing the phagocytes

52

What are two ways that a pathogen prevent encounters with phagocytes? What is an example of an organism that does both?

1. Producing C5a peptidase which degrades the chemoattractant C5a
2. Produce membrane-damaging toxins that will kill phagocytes and other cells
-Streptococcus pyrogenes, which causes strep throat, can do both

53

What membrane-damaging toxin can S. Pyrogenes produce to prevent an encounter with a phagocyte which avoids the host cell defenses?

-Streptolysin O, which is a membrane-damaging exotoxin that kills phagocytes

54

What are three ways a pathogen can avoid recognition and attachment, or opsonization, in an effort to avoid destruction by phagocytes to avoid the host defenses?

1. Pathogen capsules
2. M proteins
3. Fc receptors on antibodies

55

How can a pathogen avoid opsonization, and therefore phagocytes, through their capsules? Give an example of a microorganism that does this

-The capsules interfere with opsonization and some bind host regulatory proteins that inactivate C3b
-Streptococcus Pneumonia

56

How can a pathogen avoid opsonization, and therefore phagocytes, through M proteins? Give an example of a microorganism that does this.

-The M protein produced by the microorganism binds a regulatory protein that inactivates C3b
-This prevents opsonization and activation of the alternative pathway of the complement system
-Streptococcus Pyrogenes can do this

57

How can a pathogen avoid opsonizaiton, and therefore phagocytes, through Fc receptors? Give an example of microorganisms that can do this.

-Microorganisms will bind to the Fc receptor on antibodies and invert their orientation so the phagocyte cannot bind
-Staphlococcus aureus has protein A which binds IgG
-Streptococcus pyrogenes has protein M which binds IgG

58

How does surviving within phagocytes benefit the microorganism to avoid destruction by phagocytes? What are three ways they do this?

-Some bacteria do not avoid engulfment by a phagocyte and hide from antibodies there. This allows them to be transported to other tissues
1. Escape from phagosome
2. Prevent phagosome-lysosome fusion
3. Survive withing the phagolysosome

59

How can pathogens survive within phagocytes by escaping the phagosome? Give examples of organism that can do this.

-They escape from the phagosome prior to fusion with lysosomes
-Listeria monocytogenes and Shigella cause the lysis of the phagosomal membrane

60

How can pathogens survive within phagocytes by preventing phagosome-lysosome fusion? Give an example of an organisms that does this.

-This allows them to avoid destruction
-Salmonella sense ingestion by a macrophage, and proteins a protein that blocks the phagosome-lysosome fusion process

61

How can pathogens survive within phagocytes by surviving withing the phagolysosome? Give an example of a microorganism that can do this.

-They survive the destructive environment
-Coxiella Burnetii, which causes Q fever, is able to withstand the environment by delaying phagosome-lysosme fusion, giving it time to equip itself to survive

62

______ _____ bacteria are those that can avoid being killed by complement proteins.

Serum Resistant

63

Gram ____ bacteria are more susceptible to MAC's.

Negative

64

How do serum resistant bacteria avoid killing by complement proteins?

They attract complement regulatory proteins to their surface. This hijacks the host's protection mechanism and allows the bacteria to avoid complement proteins and delay MAC formation while infection proceeds.

65

______ _____ is an example of an organism that is a serum resistant bacteria. It causes STD's.

Neisseria gonorrhoeae

66

What are three ways microorganisms avoid antibodies to avoid host defenses?

1. IgA protease
2. Antigenic variation
3. Mimicking host molecules

67

How does IgA protease allow a pathogen to avoid antibodies and give an example of an organism that does this.

-IgA protease cleaves IgA found in mucous and secretions
-Neisseria gonorrhoeae does this

68

How does antigenic variation allow a pathogen to avoid antibodies and give an example of an organism that does this?

-Antigenic variation allows the pathogen to alter the structure of surface antigens and stay ahead of antibody production
-Neisseria gonorrhoeae varies the antigenic structure of pili

69

How does mimicking host molecules allow a pathogen to avoid antibodies and give an example of an organism that does this.

-A microorganism will cover its surface with molecules similar to those found in the host cell, causing it to appear to the host defenses as "self"
-Streptococcus pyrogenes does this by forming its capsule fro hyaluronic acid, a polysaccharide found in host tissues

70

Damage to a host can be due to _____ or _____ effects. What is the difference between the two?

-Direct
-Indirect
-Direct causes host cell destruction or tissue damage
-Indirect causes the immune system to be suppressed or overreact, and damage may help the pathogen to exit the host and spread

71

What are two things a microorganism can use to cause damage to the host?

1. Endotoxins
2. Exotoxins

72

_____ are proteins that are secreted or leak into tissues following bacterial lysis that have specific damaging effects. These are from majority gram _____ organisms.

-Exotoxins
-Positive

73

Many exotoxins are _______. Give an example of this. What does it cause?

-Foodborne
-Botulinum produced by Clostridium botulinum
-This neurotoxin is an enzyme that attacks the nervous system and causes paralysis

74

How are exotoxins commonly destroyed? What is the problem with the way the body responds to exotoxins?

-Majority are destroyed by heat
-The immune system can generate antibodies, but many exotoxins are fatal before an adequate immune response. This is why vaccination is important.

75

Give an example of an endotoxin and describe it

-Lipid A of LPS of gram-negatives
-Released upon bacterial lysis
-Heat stable and resistant

76

What does the endotoxin lipid A do?

-Lipid A of LPS triggers an inflammatory resopnse and activates innate and adaptive defenses
-It causes phagocytic cells to release enzymes for extracellular killing
-It causes overstimulation of the immune response
-It causes fever through the exogenous pyrogen interleukin, a drop in blood pressure, and sepsis

77

Endotoxins are T-________ antigens that can activate ____ cells without _____ cells.

-Independent
-B
-T

78

A _____ is the inactive form of a toxin.

Toxoid

79

What would happen if a pathogen lost its ability to produce adhesins?

-It would not attach to the surfaces of the host

80

______ is the study of disease patterns in populations?

Epidemiology

81

_____ collect and compile data about sources of disease and risk factors.

Epidemiologists

82

What is the goal of epidemiologists?

To design infection control strategies to prevent or predict the spread of disease

83

True or False: Epidemiologists are more concerned with the absolute number of disease cases than the rate of disease in the population.

False, they are more concerned with the rate

84

THe _____ ______ is the percentage of people who become ill in a population after exposure. What is the equation? What does it reflect

-Attack rate
-# of people infected / population exposed
-Reflects the infectious dose and the immune status of a population

85

The _____ ______ is the number of new cases at a specific time in a population. What does this measure? What is the equation?

-Incidence rate
-Measures the risk of an individual contracting the disease
- # of new cases / Total population

86

______ is the total number of cases at any time for a specific period in a given population. What does in reflect? What is the equation?

-Prevalence
-Reflects the overall impact of a disease on a population
-# of new and old cases / Total population

87

If the attack rate is high, the infectious dose is _____.

Low

88

______ is the incidence of disease in a defined population. What is the equation?

-Morbidity
- # of people that developed the disease / Total infected

89

Contagious diseases often have a high ____ rate.

Morbidity

90

_______ is the overall death rate in a population. What is the equation? What is it most often associated with in developed countries?

-Mortality
-# died / Total population
-Non-communicable diseases such as cancer or heart attack

91

______ - _____ ______ is the percentage of the population that dies from a specific disease. What is the equation? What disease is feared because of the high rate of this?

-Case-fatality rate
-# died / total infected
-Ebola, it has a 50% case fatality rate

92

_____ diseases have a steady presence in the population. What are examples of this in the U.S?

-Endemic
-Common cold, measles

93

_____ diseases result from an unusually large number of cases of an endemic disease or a newly introduced disease. What are examples of this?

-Epidemic
-Zika or Ebola

94

____ diseases, such as _____, result from the spread of an epidemic disease globally.

-Pandemic
-Aids

95

_____ of infection are the natural habitat where the pathogen lives. Why is the identification of this important? What are examples?

-Reserviors
-Important for disease control
-In or on an animal, human, or in the soil or water in the environment

96

True or False: Environmental reservoirs are often easier to control

False, human ones are

97

Human reservoirs of pathogens can be _____ or _____.

-Asymptomatic
-Symptomatic

98

What is an example of a disease that uses an asymptomatic human reservoir?

Up to 50% of women infected with Neisseria gonnorhoaea are asymptomatic

99

What is the chain of infection?

Reservoir of infectious agent --> portal of exit --> transmission --> portal of entry --> susceptible host

100

What two things do reservoirs of infection include?

1. Non-Human animal reservoirs
2. Environmental Reservoirs

101

Give an example of a non-human animal reservoir.

-Salmonella exists in poultry produces and is a gastrointestinal pathogen

102

_____ diseases primarily exist in animals but can be transmitted to humans. Give two examples.

-Zoonotic
-Plague, rabies

103

____ reservoirs are difficult or impossible to eliminate. Give some examples of reservoirs, and of a pathogen that lives in these.

-Environmental
-Soil, water, food
-Botulinum, tetanus

104

What are the two kinds of disease transmission?

1. Vertical
2. Horizontal

105

____ transmission happens in a pregnant woman to a fetus, a mother to an infant during childbirth, or during breastfeeding. ____ are transmitted this way.

-Vertical
-STD's

106

_____ transmission happens person to person via air, physical contact, ingestion of food or water, or a vector. What are examples of this?

-Horizontal
- Malaria
-STD's

107

____ ____ is a type of disease transmission that happens through a handshake or sexual contact. ____ ____ is important for this type of transmission. _____ is an important measure in preventing this kind of transmission. What is an example route?

-Direct contact
-Infectious dose
-Hand washing
-Fecal-oral transmission

108

_____ ____ is a type of disease transmission that occurs through things such as fomites. What are examples of fomites?

-Indirect contact
-Clothing, table tops, door knobs

109

______ transmission occurs with respiratory droplets. Where is this common? What can minimize spread?

-Droplet
-Densely populated buildings such as schools
-Spread is minimized by covering the mouth when sneezing

110

True or False: Respiratory droplets generally fall to the ground within a meter of release.

True

111

What are four ways diseases can be transmitted?

1. Direct/Indirectly
2. Food and Water
3. Air
4. Vectors

112

What are three ways food and water can become contaminated?

1. Animal products from animal's intestines
2. Cross-contamination
3. Municipal water systems that can distribute pathogens in large numbers

113

____ _____ is the transfer of a pathogen from one food to another.

Cross Contamination

114

Respiratory diseases are commonly transmitted by ____.

Air

115

How can bigger and smaller particles be transmitted through the air and cause respiratory diseases?

-Large: Trapped by mucus
-Small: can be carried into the lungs

116

Talking, laughing, singing, sneezing, and coughing can generate ____ _____, which are microbes attached to dry material that can remain suspended in the air.

Droplet nuclei

117

How can respiratory disease that are commonly transmitted through the air be controlled?

Ventilation systems such as HEPA filters

118

_____ are living organisms that carry pathogens. Give some examples.

-Vectors
-Mosquitos, flies, ticks

119

If organisms such as a fly carry a microbe on its body from one place to another, it is a ___ vector. However, if the fly participates in the life cycle of the pathogen and provides a place for it to multiply, it is a ____ vector.

-Mechanical
-Biological

120

Following a disease outbreak, the data collected is called the _____ _____. What three things are included in this?

-Descriptive study
1. Person
2. Place
3. Time

121

A _____ _____ epidemic is one that has a rapid rise in cases and suggests exposure to a single source of pathogen.

-Common-source

122

A ____ epidemic is one that has a slow rise in cases and suggests a contagious disease in a population.

Propagated

123

The first case in a disease outbreak is called the _____ _____.

Index case

124

_______ studies determine the relevancy of risk factors. What two kinds of studies are included in this? Describe them.

-Analytical
1. Retrospective, actions and events are compared
2. Prospective, looks ahead and predicts the tendency to develop disease

125

Give some examples of new emerging disease and reemerging diseases.

-Emerging: Severe Acute Respiratory Syndrome (SARS), mad cow disease, avian flu
-Reemerging: Malaria and tuberculosis

126

What three things contribute to the emergence of new diseases and reemerging of diseases?

1. Population expansion causing increased contact with disease reservoirs
2. Mass production allowing foodborne illnesses to rapidly spread
3. Climate changes causing heavy flooding

127

______ _____ infections are those that are acquired while receiving treatment in a healthcare setting.

Healthcare-Associated

128

Hospital-acquired infections are called ______ infections.

Nocosomial

129

What are three reservoirs of infectious agents in Healthcare settings?

1. Other patients
2. Invasive procedures that transmit the normal microbiota to sterile body sites that may allow infection to develop
3. Healthcare workers

130

What are three methods of transmission of infectious agents in healthcare settings?

1. Fomite: medical devices
2. Direct: healthcare worker
3. Airborne

131

In the chain of infection, what are the portals of exit or portals of entry?

Body surfaces or orifices, such as skin, intestinal tract including feces, respiratory tract including droplets and mucus, and genitals including semen and vaginal secretions

132

Vertical transmission is ____ transmission, whereas horizontal can be ____ or _____.

-Direct
-Direct or indirect

133

Give two examples of disease that are transferred through mechanical vectors.

1. Salmonella
2. Shigella

134

Give an example of a disease transferred through a biological vector

Lyme disease

135

In epidemiological studies, what three things need answered?

Who, where, and when

136

About 1/3 of all nocosomial infections occur in the urinary tract due to a ____.

Catheter

137

How could disease transmission be stoppped at the portals of entry and exit?

Entry: bandaide
Exit: Wash hands, wear a condom, cover mouth when coughing or sneezing

138

Why are diseases with long incubation periods more likely to result in an epidemic?

People are still contagious and spreading the disease even though they are asymptomatic

139

Why do influenza outbreaks in nursing homes typically have higher case-fatality rates than influenza outbreaks in a college dormitory?

The elderly have a weaker immune system

140

What are the main portals of exit from the body?

Genital, urinary, respiratory, digestive, urinogenitary, broken skin

141

True or False: A person exposed to a low dose of a pathogen may not develop the disease.

True

142

True or False: The young and the elderly are more likely to develop certain diseases.

True

143

True or False: Droplet nuclei fall quickly to the ground.

False

144

True or False: Herpes is an example of a disease that can be acquired through vertical or horizontal transmission.

True

145

Why is the rate of a nocosomial infection higher in the ER than the normal hospital?

Staff are in a bigger rush, there's a greater chance of open skin, overcrowding in the ER

146

What is the variety of respiratory infections like.

There is an enormous variety, ranging from subclinical to fatal.

147

True or False: They eyes and ears are also part of the respiratory system.

False, but they serve as portals of entry

148

What does the upper respiratory system include? What does the lower respiratory system include?

Upper: head (nose, nasal cavity) and neck (pharynx, epiglottis)
Lower: Chest (larynx, trachea, bronchii, lungs)

149

What are the differences between upper and lower respiratory infections?

-Upper: Common, uncomfortable, not life-threatening, clear without treatment in about a week
-Lower: serious and may be fatal

150

Streptococcal pharyngitis, commonly called ____ ____, is a disease of the _____ respiratory tract caused by _____ _____.

-Strep throat
-Upper
-Streptococcus Pyrogenes

151

Streptococcus pyrogenes is gram- _____, grows in _____, and its incubation period is ___-___ days.

-Positive
-Chains
-2-5

152

What are the signs and symptoms of strep throat?

Sore throat, difficulty swallowing, fever, throat is red with patches of pus and tiny hemorrhages

153

How bad are the symptoms for strep throat and how long does it last?

-Some have mild or no symptoms
-Most patients recover within a week

154

What are seven ways streptococcus pyrogenes, which causes strep throat, avoids the host immune system?

1. Adhesins with more than 80 antigenic types
2. M protein inactivates C3b
3. Protein G is an Fc receptor for IgG
4. Produces C5a peptidase, which destroys C5a
5. Streptolysins O and S that make holes in leukocyte and erythrocyte cell membranes
6.Hyaluronic acid capsule that disguise the bacteria from the immune system
7. Produce Streptococcal pyrogenic exotoxins (SPEs) that lead to high fever

155

What is unique about he streptococcus pyrogenes, which causes strep throat, adhesins?

They have more than 80 antigenic types

156

Streptolysins O and S, produces by Streptococcus pyrogenes, are ____ hemolytic.

Beta

157

Streptococcus pyrogenes naturally only infects _____, is spread by respiratory ____ or contaminated _____, can be a source of _____ infections, and individuals can be _____ ____ for weeks.

-Humans
-Droplets
-Food
-Nocosomial
-Asymptomatic carriers

158

How is streptococcus pyrogenes treated and prevented?

-Treatment: Confirm through diagnostic tests and throat culture, treat with antibiotics, which helps prevent post-streptococcal sequelae
-Prevent: Avoid crowding, proximity, and food sharing

159

What is Post-Streptococcal Sequelae? Give an example.

-Complications that develop after streptococcal infections
-Acute Rheumatic fever

160

What is acute rheumatic fever?

Can begin 1-4 weeks after streptoccocal infection recovery, causes fever, joint pains, rash, nodules under skin, and 1/3 - 1/2 develop carditis which leads to chronic rheumatic heart disease

161

Acute rheumatic fever occurs after _____ infections and can lead to chronic ____ ____ ____.

-Streptococcal
-Rheumatic heart disease

162

Diptheria is a ____ respiratory infection and is a deadly ____ - mediated disease.

-Upper
-Toxin

163

The causative agent of diptheria is ______ ______. It is ____ in morphology, a gram _____ rod, and inhibits the ____ ____ of the upper respiratory system.

-Corynebacterium diphtheriae
-Pleomorphic
-Positive
-Normal microbiota

164

What are the signs and symptoms of diptheria as it starts, develops, and later in the disease?

-Start: Mild sore throat, slight fever, extreme fatigue, malaise
-Development: Swelling of neck, formation of pseudomembrane on the tonsils and throat
-Later: Heart and kidney failure, paralysis

165

What is the pseudomembrane that forms on the tonsils and throat of people with diptheria and what is the danger of it?

-It is a thick layer formed of dead epithelial cells and pus
-It can fall off and suffocate the patient

166

True or False: Diptheria has little invasive ability.

True

167

What does the pathogenicity of diptheria result from?

It has little invasive ability, so pathogenicity results from a potent AB toxin released by the bacteria growing in the throat and can be absorbed into the blood

168

How does the AB toxin of diptheria enter host cells and what does it do?

-The B subunit attaches to a membrane receptor on the host cell
-The toxin is taken in via endocytosis
-The A subunit detaches and enters the cytoplasm, where it prevents protein synthesis and causes host cell death

169

The ____ subunit of the AB toxin binds to the host cell receptor, and the ____ subunit is an enzyme that inactivates proteins.

-B
-A

170

____ are the primary reservoir for diptheria. It is spread by ____ and acquired via ____ or ____.

-Humans
-Air
-Inhalation
-Fomites

171

What is the case fatality rate of diptheria?

10%

172

What is the treatment and prevention for diptheria?

-Treatment: injection of antitoxin and antibiotics
-Prevention: Immunization

173

Antitoxin for diptheria is acquired from ____. What is the vaccine that is used against diptheria?

-Horses
-Diptheria Tetanus Acellular Pertussis vaccine (DTP vaccine)

174

Pertussis, also known as _____ ____, is a ____ respiratory infection caused by _____ _____.

-Whooping cough
-Lower
-Bordetella Pertussis

175

Bordetella Pertussis, which causes pertussis, is a gram-_____ rod. Is it encapsulated?

-Negative
-Yes

176

What are the three stages of illness for Pertussis?

1. Catarrhal Stage
2. Paroxysmal Stage
3. Convalescent Stage

177

What happens during the catarrhal stage of pertussis?

-Inflammation of mucous membranes
-1-2 weeks of signs resembling an upper respiratory infection

178

What happens during the Paroxysmal stage of pertussis?

-Repeated sudden attacks of violent coughing, forceful inhalation of air, and "whoop" sound

179

What happens during the convlescent stage of pertussis?

-Non-contagious and coughing decrease

180

What is the pathogenesis of Bordetella Pertussis?

-Cells are inhaled nad attach to ciliated cells of respiratory epithelium
-The bacteria colonize the nasopharynx, trachea, bronchi, and bronchioles, leading to areas of collapsed lung
-The bacteria release 3 different exotoxins which are responsible for disease progression such as inhibiting phagocytes and NK cells, inducing the release of interleukins, and ciliated epithelial cell death

181

What is the chief cause of death when infected with bordetella pertussis?

-The secondary infection, pneumonia

182

Pertussis is highly ____ and spread via _____. Patients are most contagious during the _____ stage.

-Contagious
-droplets
-catarrhal

183

Pertussis is classically a disease in _____, but adults help in ____. Caregivers are _____.

-Infants
-transmission
-Reservoirs

184

What are the treatment and prevention strategies for Pertussis?

-Treatment: Antibiotics are effective in the catarrhal stage, but not in the paroxysmal stage
-Prevention: Vaccine

185

Diptheria has ____ toxin(s), pertussis has _____.

-1
-3

186

How is croup different from whooping cough?

Croup is viral

187

Influenza is a _____ respiratory tract infection. It is a _____ ____ with three major types based on the ____ ____.

-Lower
-RNA virus
-Protein coat

188

What are the differences in the three causative agents of the Flu?

-Type A: causes the most serious disease
-Type B: less extensive with less severe disease
-Type C: Minor importance

189

Influenza A is in the _______ family. It is an _____ virus, with ______ ____ embedded in the envelope.

-Orthomyxovirus
-Enveloped
-Glycoprotein spikes

190

What are the glycoprotein spikes embedded in the flu virus envelope and what do they do?

-Hemagglutinin antigen (HA): attaches to receptors on ciliated host epithelial cells
-Neuraminidase Antigen (NA): Releases newly formed virions from the host cell

191

Subtypes of the influenza virus is based on the _____ ____ variations.

Glycoprotein spike

192

Influenza has a ___ day incubation period. What are the signs and symptoms?

-2
-Headache, fever, soar throat, muscle pain that peak at 6-12 hours
-dry cough develops and worsens over a few days
-Acute systems last 1 week
-lingering cough, fatigue, weakness last additional days or weeks

193

What is the pathogenesis of Influenza?

-Droplets are inhaled or transferred to the eyes and nose via fomites
-Virions attach to the receptors of respiratory epithelial cells via hemagglutinin antigen
-virions enter cells via endocytosis and synthesize more RNA and proteins
-Within 6 hours, the mature virions bud from the host cell via neuraminidase antigen and spread
-Infected cells die, slough off, and destroy the mucociliary escalator

194

What is the treatment and prevention of influenza?

-Treatment: antiviral drug and vaccination protect exposed people until the vaccine successfully induces immunity
-Prevention: Mutlivalent vaccine against the three most important strains in circulation

195

Why is a new flu shot needed each year?

Antigenic drift causes rapid mutation of the virus

196

True or False: A large percentage of people infected with influenza die each year.

False, only a small percentage die

197

Most deaths from influenza are due to _____ infections, such as _____. Epidemics occur _____, and pandemics occur ______.

-Secondary
-Pneumonia
-Annually
-Periodically

198

______ _____ causes minor mutations in the henagglutinin antigen and neuraminidase antigen genes, often as a result of a single amino acid change. It is responsible for _____ influenza.

-Antigenic drift
-Seasonal

199

____ ____ is the uncommon simultaneous infection with two different influenza viruses allowing the mixture of the RNA segments. This causes ______ influenza.

-Antigenic shift
-Pandemic

200

True or False: Rheumatic fever is an autoimmune reaction that results from molecular mimicry of S. pyrogenes.

True

201

True or False: Common cold is a viral infectious disease of the lower respiratory system causing valley fever.

False, it is an upper respiratory disease

202

True or False: Cocciidioidomycosis is a bacterial infection of the upper respiratory system causing valley fever.

False, it is a fungal infection of the lower respiratory system

203

True or False: Tuberculosis is highly contagious but not that easy to catch.

True

204

True or False: Rheumatic heart disease is the inflammation of the heart valves, resulting in damage, leak and heart murmur.

True

205

True or False: The incidence of whooping cough rises promptly when pertussis immunizations are stopped because unrecognized adult carriers transmit the infection to infants.

True

206

Why are there no vaccines against S. pyrogenes?

Because there are over 80 antigenic types

207

Which virulence factor is responsible for S. pyrogenes' beta hemolytic property?

Streptolysins O and S

208

How does diptheria toxin kill cells?

It is an AB exotoxin that denatures ribosomes

209

Why are there so many deaths from influenza?

Secondary infections

210

Can contamination of the eye lead to upper respiratory infection?

Yes, organisms can be carried through the nasolacrimal duct

211

What is the source of the virus that causes hantavirus pulmonary syndrome?

Rodents

212

How do alcoholism and cigarette smoking predispose a person to pneumonia?

-Compromised/weakened immune system
-Mucociliary escalator is impaired

213

During convalescence, the person is in _____, however they may still be ______.

-Recovery
-Contagious

214

What four things affect the length of the convalescence period?

1. Amount of damage
2. Nature of the pathogen/ infectious dose
3. Site of infection
4. Overall health of the patient

215

What is the function and structure of the digestive system?

-Function: to convert food into a source of energy and raw materials for growth
-Structure: A hollow tube extending from the mouth to the anus

216

What does the gastrointestinal tract refer to?

The stomach and intestines

217

Carb digestion starts in the ____ with the enzyme ____. Protein digestion starts with the enzyme ____ in the ______. Fat digestion starts in the ______.

-Mouth
-Amylase
-Pepsin
-Stomach
-Duodenum

218

What four things comprise the upper digestive system?

1. Mouth
2. Salivary glands
3. Esophagus
4. Stomach

219

After food passes through the upper digestive system, it is called _____.

-Chyme

220

What happens in the mouth and salivary glands to food? What kinds of immunity are present here?

-Physical digestion (chewing) and chemical digestion (amylase)
-IgA, lysozyme, lactoferrin

221

What can poor saliva production lead to?

Tooth decay

222

The esophagus connects the ____ to the ____. ____ pushes the food through. Mucus and saliva containing secretory ____ bathes the lining.

-Mouth
-Stomach
-Peristalsis
-IgA

223

The ____ is an elastic, muscular wall that breaks down food. It is highly ____ with gastric juices to denature and digest proteins.

-Stomach
-Acidic

224

What does the lower digestive system include?

The small intestine, pancreas, liver, and large intestine

225

Alkaline fluids such as ____ are secreted from the live an pancreas to neutralize the acidic ____ from the stomach. This helps break down _____.

-Bile
-Chyme
-Fat

226

What is the main function of the large intestine?

To absorb water and vitamins

227

Microbes make up about ____ of fecal weight.

-1/3

228

What do normal microbiota do in the large intestine?

Help with digestion of fiber, prevent pathogen colonization, and produce vitamins

229

Gastritis is a _____ infection of the _____ digestive system. It is caused by ______ _____, a gram _____ organism.

-Bacterial
-Upper
-Helicobacter Pylori
-Negative

230

What are the signs and symptoms of Gastritis?

-Peptic ulcers of the stomach, duodenum may cause abdominal pain, bleeding

231

Most gastritis infections are ______. Stomach ____ can develop from gastritis.

-asymptomatic
-Cancer

232

What kinds of things increase the chances of developing a stomach ulcer?

Alcohol, chronic vomiting, medication, diet such as salt, and smoking increases chances 17X

233

What four things are involved in the pathogenesis of Helicobacter pylori?

1. It survives the acidic environment of the stomach
2. It produces effector protein CagA (cytotoxin-associated gene), which it injects into host cells to interfere with signaling
3.It produces exotoxin VacA (vacuolating cytotoxin) that damages mucus-producing epithelial cells
4. Causes damage to epithelial cells and the inflammatory response results in decreased mucus production

234

What does the decreased mucus production caused by Helicobacter pylori cause?

Peptic ulcer

235

How does Helicobacter pylori survive the acidic environment of the stomach?

-Converts urea to ammonia by producing urease, and ammonia neutralizes stomach acid
-Uses flagella to burrow withing the mucus layer and get to epithelial cells, which have a more neutral pH

236

How many adults in the US are infected with Helicobacter pylori?

1 in 5, or 20%

237

How is Helicobacter pylori transmitted?

Through the fecal-oral route, flies may transmit from feces, or the bacteria may be found in well water

238

How is gastritis treated and prevented?

-Antibiotics and medication inhibit acid production

239

Mumps is a ___ disease of the ___ digestive system caused by ____ ____.

-Viral
-Upper
-Mumps virus

240

What are signs and symptoms of mumps?

Onset is marked by fever, loss of appetite, and headache, and followed by painful swelling of one or both parotid glands. Spasms of underlying muscle makes talking and chewing hard.

241

What is the pathogenesis of mumps?

The virus is inhaled via droplets, spreads via the bloodstream, and multiplies in parotid salivary glands
-Inflammation yields swelling and pain
-Incubation time is 15-21 days

242

_____ are the only natural host for mumps, and because there is ____ antigen, infection results in lifelong immunity.

-Humans
-One

243

Is mumps common in the U.S?

-It used to be prior to the MMR vaccine
-Now it is rare but outbreaks to occur due to waning immunity in college students and other young adults. This is due to close living space. A third vaccination is recommended.

244

What is the treatment and prevention for mumps?

-No treatment
-MMR vaccine for prevention

245

True or False: Mumps is a good candidate for eradication.

True

246

A general name for bacterial infections of the lower digestive tract is ____, or Stomach ____.

-Gastroenteritis
-Flue

247

What are general symptoms of bacterial infections in the small and large intestines?

-Small: copious watery diarrhea
-Large: smaller amounts of diarrhea containing mucus, pus, and sometimes blood

248

_____ refers to illnesses with blood or pus in the feces.

Dysentery

249

How are bacterial infections of the lower digestive tract generally transmitted? What control measures should be taken?

-Through the fecal-oral route
-Sewage treatment, handwashing, chlorinating water

250

Bile is produced in the ____ and stored in the _____.

-Liver
-Gallbladder

251

How many organisms populate the flora of the human mouth?

600

252

What is the function of saliva?

Aids in softening food, contains antimicrobial agents (IgA, lysozyme, lactoferrin), and aids in digesting carbs

253

At least _____ unrelated viruses can cause hepatitis.

5

254

______ is irreversible damage to the liver.

Cirrhosis

255

Cholera is a ____ disease of the ____ digestive system caused by _____ ____. It can grow in both ___ and ____ conditions.

-Bacterial
-Lower
-Vibrio cholerae
-Saltine and Alkaline

256

What are the signs and symptoms and what are the dangers of these in Cholera?

-Severe watery diarrhea
-Can cause severe dehydration, leading to organ failure and death

257

Vibro cholerae has several _____ ____, is sensitive to _____, has a large ______, and the incubation time is ____ hours to ____ days.

-Antigen serotypes
-Acid
-ID50
-12
-4

258

A general name for bacterial infections of the lower digestive tract is ____, or Stomach ____.

-Gastroenteritis
-Flue

259

What are general symptoms of bacterial infections in the small and large intestines?

-Small: copious watery diarrhea
-Large: smaller amounts of diarrhea containing mucus, pus, and sometimes blood

260

_____ refers to illnesses with blood or pus in the feces.

Dysentery

261

How are bacterial infections of the lower digestive tract generally transmitted? What control measures should be taken?

-Through the fecal-oral route
-Sewage treatment, handwashing, chlorinating water

262

Bile is produced in the ____ and stored in the _____.

-Liver
-Gallbladder

263

How many organisms populate the flora of the human mouth?

600

264

What is the function of saliva?

Aids in softening food, contains antimicrobial agents (IgA, lysozyme, lactoferrin), and aids in digesting carbs

265

At least _____ unrelated viruses can cause hepatitis.

5

266

______ is irreversible damage to the liver.

Cirrhosis

267

Cholera is a ____ disease of the ____ digestive system caused by _____ ____. It can grow in both ___ and ____ conditions.

-Bacterial
-Lower
-Vibrio cholerae
-Saltine and Alkaline

268

What are the signs and symptoms and what are the dangers of these in Cholera?

-Severe watery diarrhea
-Can cause severe dehydration, leading to organ failure and death

269

Vibrio cholerae has several _____ ____, is sensitive to _____, has a large ______, and the incubation time is ____ hours to ____ days.

-Antigen serotypes
-Acid
-ID50
-12
-4

270

How does vibrio cholerae infect its host?

-It adheres to epithelial cells of the small intestine, establishes infection, and produces cholera toxin, an AB exotoxin
-The B subunit of the toxin attaches to receptors of microvilli
-A portion of the toxin enters cells and causes them to secrete chloride ions. Sodium ions and water follow.
-The volume of fluid secreted from the microvilli is too much to be absorbed, causing diarrhea

271

How is vibrio cholerae normally transmitted, and what is the most common source?

-Fecal-oral route
-Fecally contaminated water is the most common source

272

What is the risk of Vibrio cholerae O139 strand?

-It is a new strand with an acquired capsule that even infects people with immunity to the pandemic strain

273

What are the treatment and prevention strategies for vibrio cholerae?

-Treatment: Replacement of fluids and electrolytes
-Prevention: Sanitation and safe water supplies and two vaccines are available

274

The causative agent of Shigellosis is _____ species of _____. The most virulent of these is _____ _____.

-Four
-Shigella
-Shigella dysenteriae

275

Why is Shigella dysenteriae the most virulent species that cause Shigellosis?

-It produces 1000X more shigella toxin

276

What are signs and symptoms of Shigellosis?

-Dysentery, headache, vomiting, fever, stiff neck, convulsions, joint pain

277

Who is Shigellosis often fatal for?

Infants in developing countries

278

Describe the pathogenesis of Shigella.

-M cells take up Shigella cells and transport them across the epithelium
-Shigella is taken up by macrophages, multiplies, and exits the macrophage, which kills the macrophage
-They induce epithelial cells to take them in, where they multiply more
-Cause actin to polymerize in the host cell forming an "actin tail" that can propel them to neighboring cells
-Infected cells slough off, leading to inflammation

279

Some strains of Shigella produce potent ____ toxin, an ___ toxin. This toxin is carried in _____.

-Shiga
-AB
-Cattle

280

Shigella is a disease of _____, transmitted via the __- ____ route. It has a _____ infectious dose because it is not easily killed by _____ _____.

-Humans
-Fecal-oral
-low
-Stomach acid

281

True or False: In populations with poor sanitation, Shigella spreads rapidly

True

282

What are the treatment and prevention strategies for Shigellosis?

-Treatment: Replace lost fluids and salt
-Prevention: sanitation, no vaccine available

283

Which of these four can be considered virulence factors: adhesins, capsules, endotoxins, proteases

All four

284

True or False: Adhesins are found on host cells.

False, they are on pili of bacteria

285

In general, what are the stages of disease?

1. Transmission
2.Adherence
3. Colonization
4. Invasion (induce inflammation or produce toxins)

286

______ occurs when bacteria overcome host defenses and the host is overwhelmed by the dose and virulence.

-Infection

287

Higher dose, and ____ ID50, both pose a ____ risk of disease.

-Lower
-Greater

288

Mary Typhoid is an example of a ____ of typhoid fever.

-Carrier

289

Can bacteria lacking pili cause disease?

No, they cannot attach to the body and are swept away

290

How are bioflims an advantage for bacterial survival?

In a biofilm the bacteria can avoid phagocytosis and antibodies

291

Why are capsules considered a virulence factor?

They block opsonization and MACs

292

Tuberculosis results form invasion of ______ _____. It is a ______ infection of the _____ respiratory tract.

-Mycobacterium tuberculosis
-bacterial
-lower

293

Hantavirus causes _____ _____ _____ and is spread by _____. It is a _____ infection of the ____ respiratory tract.

-Hantavirus pulmonary syndrome
-Rodents
-Viral
-Lower

294

Coccidiomycosis, also called ______ _____, has an _____ reservoir. It is a ____ infection of the respiratory tract.

-Valley Fever
-Environmental
-fungal

295

The common cold is caused by ______. It is a _____ infection of the ______ respiratory tract.

-Rhinovirus
-Viral
-upper

296

What is the treatment for measles?

There is no treatment, just bed rest, fluid and fever control