20 Pathogenic Interactions: How Microbial Diseases Spread

Question 1

Define “reservoir”

Answer 1

The natural habitat of a microbe that supports its growth & survival, and from where the infection begins

Question 2

Name of an infected human who does NOT show signs or symptoms of a disease, but is still able to transmit the microbe.

Answer 2

Carrier

Question 3

What kind of diseases are transmitted from animal reservoirs?

Answer 3

“zoonotic” diseases

Question 4

3 mechanisms of transmission?

Answer 4

1. Contact transmission
2. Droplet transmission
3. Airborne transmission

Question 5

2 types of contact transmission?

Answer 5

1. Direct contact transmission

2. Indirect contact transmission

Question 6

Most common and important mode of transmission?

Answer 6

Contact transmission

Question 7

What is direct contact transmission?

Answer 7

Direct, physical contact b/w an infected and susceptible person > microbe gets transferred

Question 8

What is indirect contact transmission?

Answer 8

Transfer of microbe from person to an intermediate, THEN to a susceptible person

Question 9

In indirect contact transmission, what is a “vehicle”?

Answer 9

An intermediate that is contaminated food and/or water

Question 10

In indirect contact transmission, what is a “fomite”?

Answer 10

An intermediate that is a contaminated inanimate object (e.g. doorknob)

Question 11

In indirect contact transmission, what is a “vector”?

Answer 11

An intermediate that is an infected animal or insect.

Question 12

Hosts of monkeypox include rodents and monkeys. If they transfer it to another animal, who then passes it on to humans, what kind of contact transmission is this?

Answer 12

Indirect contact transmission (via a vector)

Question 13

Define “droplet” transmission:

Answer 13

Large drops of respiratory secretions (eg. mucus from a sneeze) that are immediately inhaled after release

Question 14

How far do the large droplets of “droplet” transmission usually travel?

Answer 14

<1 m

Question 15

Define “airborne” transmission?

Answer 15

Microbes released into the air can float freely, or become associated with dust particles > Dispersed by air currents

Question 16

How soon do “droplets” settle onto a surface?

Answer 16

After a few seconds

Question 17

How soon does it take for microbes of “airborne” transmission remain suspended in the air?

Answer 17

Hours

Question 18

T or F: Airborne and droplet transmission are the same phenomenon.

Answer 18

F

Question 19

3 ways to ctrl the spread of microbial diseases?

Answer 19

1. Ctrl the reservoir (i.e. ctrl at the source)
2. Ctrl the susceptible pop (i.e. limit number of new hosts)
3. Ctrl the transmission

Question 20

Why is it difficult to control human reservoirs?

Answer 20

Bc they can be asymptomatic carriers of a microbe

Question 21

How can animal reservoirs be controlled?

Answer 21

1. Immunization

2. Slaughter

Question 22

How can environment reservoirs be ctrled?

Answer 22

1. De-contaminate

2. Avoid contact

Question 23

How can a susceptible pop be ctrled?

Answer 23

1. Improve living conditions, general health, and nutrition > maintains strong immune sys
2. Public ed. > promote vaccination, avoid high-risk behaviours, etc.

Question 24

How can indirect contact be ctrled?

Answer 24

1. Provide clean water and prevent contamination of foods
2. Remove vectors
3. Prevent fomite contamination (e.g. use disinfectants)

Question 25

How can airborne transmission be ctrled?

Answer 25

Special air flow systems ("neg. pressure" rooms > air continuously flows in > infected ind's infection can't flow out)

Question 26

How can droplet/direct contact transmission be ctrled?

Answer 26

1. Barrier precautions (e.g. masks, gloves) | 2. Cover sneeze, wash hands,e tc.

Question 27

What is a "Disease Control Network"?

Answer 27

Network of inds and organizations who identify, track, and ctrl infectious diseases

Question 28

Number 1 public health practice that's been the most successful in decreasing the incidence of infectious diseases?

Answer 28

Ensuring a clean drinking water supply

Question 29

List two worldwide issues associated with infectious diseases.

Answer 29

1. First-world countries are disproportionately much better off than are third-world countries 2. New infectious diseases are continuing to appear

Question 30

Define "Healthcare Associated Infections" (HAIs)

Answer 30

Infectious diseases that are acquired during the course of delivering or receiving healthcare

Question 31

What 3 things can put pts in a healthcare facility at risk for contracting Healthcare Associated Infections?

Answer 31

1. Pt's health status and type of medical procedure 2. Characteristics of the microbe to which the pt is exposed (e.g. are biofilms produced?) 3. The environment (physical surroundings and infrastructure) (e.g. improper sanitation, overcrowding, excessive movement of pts)

Question 32

2 ways for healthcare providers to acquire Healthcare Associated Infections?

Answer 32

1. from pts via airborne, droplet, contact, etc. | 2. from accidental occupational exposure > pathogens present in blood and other bodily fluids

Question 33

To whom are "Routine (or Standard) Precautions" applied?

Answer 33

to ALL pts, ALL healthcare providers, ALL the time

Question 34

To whom are "Additional Precautions" applied?

Answer 34

to pts known or suspected to be carrying a v. contagious pathogen

Question 35

3 basic elements of "Routine Precautions"

Answer 35

1. Risk Assessment 2. Risk Reduction Strategies 3. Education

Question 36

Additional Precautions are undertaken when...

Answer 36

routine precautions are not enough

Question 37

Three types of precautions considered "Additional Precautions"

Answer 37

1. Droplet 2. Contact 3. Airborne

Question 38

This is a key strategy in all Infection Control and Prevention programs

Answer 38

Hand hygiene

Question 39

Why wash hands? (2)

Answer 39

1. Because they get dirty | 2. Bc it's one of the most effective ways to reduce contact transmission of microorganisms

Question 40

In healthcare settings, what kind of soap should be used?

Answer 40

Antimicrobial soap

Question 41

Which is better? Alcohol-based hand rub or antimicrobial soap?

Answer 41

Alcohol-based hand rub

Question 42

What's the purpose of hand washing?

Answer 42

To remove transient (possibly pathogenic) microbes so that they aren't transmitted (NOT for sterilizing your hands)