20 Pathogenic Interactions: How Microbial Diseases Spread Flashcards
Define “reservoir”
The natural habitat of a microbe that supports its growth & survival, and from where the infection begins
Name of an infected human who does NOT show signs or symptoms of a disease, but is still able to transmit the microbe.
Carrier
What kind of diseases are transmitted from animal reservoirs?
“zoonotic” diseases
3 mechanisms of transmission?
- Contact transmission
- Droplet transmission
- Airborne transmission
2 types of contact transmission?
- Direct contact transmission
2. Indirect contact transmission
Most common and important mode of transmission?
Contact transmission
What is direct contact transmission?
Direct, physical contact b/w an infected and susceptible person > microbe gets transferred
What is indirect contact transmission?
Transfer of microbe from person to an intermediate, THEN to a susceptible person
In indirect contact transmission, what is a “vehicle”?
An intermediate that is contaminated food and/or water
In indirect contact transmission, what is a “fomite”?
An intermediate that is a contaminated inanimate object (e.g. doorknob)
In indirect contact transmission, what is a “vector”?
An intermediate that is an infected animal or insect.
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?
Indirect contact transmission (via a vector)
Define “droplet” transmission:
Large drops of respiratory secretions (eg. mucus from a sneeze) that are immediately inhaled after release
How far do the large droplets of “droplet” transmission usually travel?
<1 m
Define “airborne” transmission?
Microbes released into the air can float freely, or become associated with dust particles > Dispersed by air currents
How soon do “droplets” settle onto a surface?
After a few seconds
How soon does it take for microbes of “airborne” transmission remain suspended in the air?
Hours
T or F: Airborne and droplet transmission are the same phenomenon.
F
3 ways to ctrl the spread of microbial diseases?
- Ctrl the reservoir (i.e. ctrl at the source)
- Ctrl the susceptible pop (i.e. limit number of new hosts)
- Ctrl the transmission
Why is it difficult to control human reservoirs?
Bc they can be asymptomatic carriers of a microbe
How can animal reservoirs be controlled?
- Immunization
2. Slaughter
How can environment reservoirs be ctrled?
- De-contaminate
2. Avoid contact
How can a susceptible pop be ctrled?
- Improve living conditions, general health, and nutrition > maintains strong immune sys
- Public ed. > promote vaccination, avoid high-risk behaviours, etc.
How can indirect contact be ctrled?
- Provide clean water and prevent contamination of foods
- Remove vectors
- Prevent fomite contamination (e.g. use disinfectants)
How can airborne transmission be ctrled?
Special air flow systems (“neg. pressure” rooms > air continuously flows in > infected ind’s infection can’t flow out)
How can droplet/direct contact transmission be ctrled?
- Barrier precautions (e.g. masks, gloves)
2. Cover sneeze, wash hands,e tc.
What is a “Disease Control Network”?
Network of inds and organizations who identify, track, and ctrl infectious diseases
Number 1 public health practice that’s been the most successful in decreasing the incidence of infectious diseases?
Ensuring a clean drinking water supply
List two worldwide issues associated with infectious diseases.
- First-world countries are disproportionately much better off than are third-world countries
- New infectious diseases are continuing to appear
Define “Healthcare Associated Infections” (HAIs)
Infectious diseases that are acquired during the course of delivering or receiving healthcare
What 3 things can put pts in a healthcare facility at risk for contracting Healthcare Associated Infections?
- Pt’s health status and type of medical procedure
- Characteristics of the microbe to which the pt is exposed (e.g. are biofilms produced?)
- The environment (physical surroundings and infrastructure) (e.g. improper sanitation, overcrowding, excessive movement of pts)
2 ways for healthcare providers to acquire Healthcare Associated Infections?
- from pts via airborne, droplet, contact, etc.
2. from accidental occupational exposure > pathogens present in blood and other bodily fluids
To whom are “Routine (or Standard) Precautions” applied?
to ALL pts, ALL healthcare providers, ALL the time
To whom are “Additional Precautions” applied?
to pts known or suspected to be carrying a v. contagious pathogen
3 basic elements of “Routine Precautions”
- Risk Assessment
- Risk Reduction Strategies
- Education
Additional Precautions are undertaken when…
routine precautions are not enough
Three types of precautions considered “Additional Precautions”
- Droplet
- Contact
- Airborne
This is a key strategy in all Infection Control and Prevention programs
Hand hygiene
Why wash hands? (2)
- Because they get dirty
2. Bc it’s one of the most effective ways to reduce contact transmission of microorganisms
In healthcare settings, what kind of soap should be used?
Antimicrobial soap
Which is better? Alcohol-based hand rub or antimicrobial soap?
Alcohol-based hand rub
What’s the purpose of hand washing?
To remove transient (possibly pathogenic) microbes so that they aren’t transmitted (NOT for sterilizing your hands)
