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Micro BIO 220 Part 1 > Lecture 10 > Flashcards

Lecture 10 Flashcards

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1
Q

What are 4 major stages in development of an infectious disease?

A

Contact, colonization, infection, disease

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2
Q

What is the human microbiome?

A

Microbes associated with healthy humans (normal biota)

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3
Q

What is a major goal of the human microbiome project?

A

To identify microbial communities present on the human body under various conditions

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4
Q

What are some examples of sites of the body

that harbor a known normal microbiota?

A

Skin, respiratory tract, gastrointestinal tract, urethra, genitalia, vagina, eye, ear

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5
Q

What portions of the body are essentially free of microbes in a healthy human?

A

Heart, liver, kidneys and bladder, brain and spinal cord, muscles, bones, ovaries, glands, sinuses, ear, eye

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6
Q

Do all sites in the human microbiome contain the same sorts of microbes?

A

nah

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7
Q

What are the three benefits that the normal

human microbiome provides to the host?

A
  1. Protect from infection
  2. Aiding in carbohydrate digestion
  3. Production of vitamins
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8
Q

At what stages in life are humans colonized by

microbes?

A

Infant

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9
Q

What Is a pathogen?

A

A microbe whore relationship with its host is parasitic and results in infection/ disease

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10
Q

What is pathogenicity?

A

The potential to cause infection or disease

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11
Q

What is true pathogens?

A

Capable of causing disease in healthy persons with normal immune defenses

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12
Q

What is opportunistic pathogens?

A

Cause disease when the host’s defenses are compromised. PART OF NORMAL MICROBIOME OF A HEALTHY HUMAN.

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13
Q

What is virulence?

A

Ability to establish itself in a host and cause damage

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14
Q

What is a virulence factor?

A

Any characteristic of a microbe that contributes to its ability to establish itself in the host and cause damage

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15
Q

What is the infectious dose of a pathogen?

A

The minimum number of microbial pathogens necessary to cause an infection to proceed

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16
Q

Do pathogens with a high virulence have a high or low infectious dose?

A

low

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17
Q

What are 5 major steps in the progress of an infection?

A
  1. Finding a portal
  2. Attaching firmly
  3. Surviving host defenses
  4. Causing damage
  5. Exiting host
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18
Q

What are the 4 major portals of entry on a human host?

A
  1. Skin
  2. Gastrointestinal tract
  3. Respiratory tract
  4. Urogenital tract
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19
Q

Call all pathogens enter and exit any of these portals?

A

NO

20
Q

Why is adhesion or attachment usually a prerequisite for a potential pathogen to cause disease?

A

The body has many mechanisms for flushing microbes from tissues

21
Q

What are some examples of adhesion mechanisms or structures involved in adhesion?

A

In BACTERIA: fimbriae, pili, adhesive slimes or capsules, surface proteins.
Viruses attach to host cells by specialized receptors (spike proteins).
PARASITIC WORMS have suckers, hooks, and barbs for attachment.

22
Q

What are antiphagocytic factors and ways to avoid phagocytosis?

A

They are virulence factors that help pathogens avoid phagocytes.

  1. Leukocidins: kill phagocytic cells outright
  2. Slime layer/capsule: makes it hard for phagocyte to engulf pathogen
  3. Bacteria avoid digestion and survive inside the phagocyte
23
Q

What are three ways that microorganisms cause damage to their host?

A
  1. Directly through enzymes
  2. Directly through toxins
  3. Indirectly by inducing the hosts defenses to respond inappropriately
24
Q

What are exoenzymes?

A

Enzymes secreted by microbes that break down and inflict damage on tissues

25
Q

What are examples of exoenzymes?

A
  1. Mucinase: digests the protective cpating on mucous membranes
  2. Hyaluronidase: digests the substance that cements animal cells together
  3. Coagulase: causes clotting of blood or plasma
  4. Kinase: dissolves fibrin clots
26
Q

What are differences between exotoxins and endotoxins?

A 
Exotoxins:
1.	Low toxicity
2.	Specific to a cell type
3.	Small proteins
4.	Heat
5.	Can be converted to toxoid
6.	Stimulate antitoxins
7.	No fever
8.	Secreted from live cell
9.	Gram positive and negative
Endotoxins:
1.	High toxicity
2.	Systemic
3.	Lipopolysaccharide of cell wall
4.	No heat
5.	Cannot be converted
6.	Does not stimulate toxins
7.	Have fever
8.	Released by cell by shielding
9.	Gram negative
27
Q

List the definitions of these infection types.

A

Localized infection: Microbes establish infection but remain confined to a specific tissue Systemic

infection: Infection spreads to multiple tissues/sites within the body Mixed or

Polymicrobial infection: Several distinct microbial pathogens establish themselves simultaneously at the infection site

Primary infection: The initial infection

Secondary infection: A second infection caused by a different microbe that complicates recovery/treatment from the primary infection.

Acute infection: Infection comes on rapidly, with severe but short-lived effects

Chronic infection: Infection that progresses and persists over a long period of time.

Asymptomatic infection: Infection occurs, but no outward signs are apparent, and patient does not notice symptoms.

28
Q

What are portals of exit and why is it important for a pathogen to exit the host?

A

It is a specific avenue by which pathogens to exist. It is necessary for the pathogen to infect other hosts.

29
Q

What is the difference between signs and symptoms of infection?

A

A SIGN is objective evidence of disease as noted by an observer. A SYMPTOM is a subjective evidence of disease as sensed by the patient.

30
Q

What occurs during the incubation period, the prodromal stage, and the convalescent period of infection?

A

INCUBATION:
1. Microbe is multiplying at the portal of entry but has not caused enough damage to elicit symptoms
PRODROMAL:
1. 1-2 day period when the earliest notable symptoms of infection appear
INFECTION:
1. Infectious agent multiplies at high levels, exhibits greatest toxicity, becomes well established in host tissue

31
Q

What is meant by the reservoir of a pathogen?

A

The primary habitat in the natural world from which a pathogen originates

32
Q

What is meant by carrier?

A

An individual who shelters a pathogen, spreads it to others and who may not have experienced a disease due to the microbe

33
Q

What is the difference between a biological and a mechanical vector?

A

BIOLOGICAL: actively participates in a pathogen’s life cycle
MECHANICAL: carries the microbe accidentally on its body parts

34
Q

What is a zoonosis?

A

Infectious indigenous to animals but transmissible to humans

35
Q

What are the distinctions between communicable, contagious, and noncommunicable infectious diseases?

A

COMMUNICABLE: an infected hose can transmit the infectious agent to another host and establish infection
CONTAGIOUS: highly communicable through direct contact
NONCOMMUNICABLE: disease that does not typically arise through transmission of the infectious agent from host to host

36
Q

What is latency?

A

Dormant state of microbes in certain chronic infectious diseases where the microbe is present in the host but signs of disease have not developed

37
Q

What are nosocomial infections?

A

Infections developed during a hospital stay

38
Q

What are the factors?

A
  1. Compromised hosts (patients often have weakened immune systems)
  2. Collection point for pathogens
  3. Lowered defenses permit normal biota to enter the body
  4. Infections acquired directly or indirectly from fomites, medical equipment, other patients, medical personnel, visitors, air, and water
39
Q

What is the most common type?

A

URINARY TRACT

40
Q

What are Koch’s postulates?

A
  1. The pathogen must be present in all cases of the disease, and typically absent (or not abundant) in healthy hosts
  2. The pathogen must be isolated from a diseased host and identified
  3. The isolated pathogen must cause disease when introduced to a new host
  4. The pathogen must be re-isolated from the new host
41
Q

What are 3 reasons why it cannot be applied to every pathogen or infectious disease?

A
  1. Some infectious agents cannot be readily isolated or grown in the lab
  2. Some infections cannot be elicited in animals, and experiments cannot be done in humans for ethical reasons
  3. Difficult to determine causation in polymicrobial diseases caused by more than one microbe
42
Q

What is epidemiology?

A

Study of frequency and distribution of disease and other health-related factors in defined populations

43
Q

What is meant by prevalence, incidence, and mortality rate?

A
  1. Prevalence: Total number of existing cases with respect to the entire population
  2. Incidence: Measures the number of new cases over a certain time period
  3. Mortality rate: Number of deaths in a year due to a given disease
44
Q

What is reportable or notifiable diseases?

A

must be reported to authorities

45
Q

What are these epidemiological terms?

A
  1. Endemic: An infectious disease that exhibits a relatively steady frequency over a long time period in a particular geographic locale
  2. Sporadic: Occasional cases are reported at irregular intervals at random locales
  3. Epidemic: When statistics indicate that the prevalence of an endemic or sporadic disease is increasing beyond what is expected for a population Time period is not defined; can be measured in hours to years Exact percentage of increase needed before an outbreak qualified as an epidemic is also not defined
  4. Pandemic: Spread across of an epidemic across continents

Micro BIO 220 Part 1 (18 decks)

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