Chain of Infection (U1)

Question 1

What is the chain of infection?

Answer 1

1. Etiological/infection agent
2. Reservoir
3. Portal of Exit
4. Method of transmission
5. Portal of entry
6. Susceptible host

Question 2

Etiological/infection definition?

Answer 2

Disease causing MO

Question 3

Reservoir

Answer 3

Place where MOs thrive and survive (host)
- Ex. water, food, skin

Question 4

Portal of exit definition?

Answer 4

Any way for a MO to leave the reservoir
- Ex. nose, mouth

Question 5

Method of transmission definition?

Answer 5

Way for MOs to spread (in)direct

Question 6

Portal of entry definition?

Answer 6

The place where the MO enters the body

Question 7

Susceptible host definition?

Answer 7

Person susceptible to infection
- Compromised host= increased risk

Question 8

Chain of infection definition?

Answer 8

Mode to understand how infection spreads
- Each link must be present

Question 9

What are the two methods of transmission (contact)?

Answer 9

Indirect and direct

Question 10

What are the different methods of direct transmission?

Answer 10

Person to person, animal to person and mother to unborn child

Question 11

What is person to person?

Answer 11

Direct bacteria/virus/germ from one person to another

Question 12

What is animal to person?

Answer 12

Bitten/scratched by an infected animal
- Death= extreme cases
- Animal waste can be hazardous

Question 13

What is mother to unborn child?

Answer 13

Pregnant women may pass infectious diseases onto fetus via placenta
- Can be during labour/delivery via birth canal passage

Question 14

What are the different methods of indirect transmission?

Answer 14

Inanimate object, vector, food borne, droplet transmission, airborne/particle transmission

Question 15

What is inanimate object?

Answer 15

Pathogens linger (fomites)

Question 16

What is vector?

Answer 16

Living organism, indirect carriers
- Ex. fleas

Question 17

What is food borne?

Answer 17

Infection via contaminated food
- Improper storage, handling, prep

Question 18

What is droplet transmission?

Answer 18

Through cough/sneeze, expels droplets through air
- Travels three feet, too large to stay in air
- Contacts mouth/nose/eyes
- Crowded/indoor environment can promote chance of droplet transmission

Question 19

What is airborne transmission?

Answer 19

Travels through air because they’re smaller than droplets
- Particles suspended in air extended periods of time and travel air currents
- Breathe in airborne pathogen

Question 20

What is blood borne transmission

Answer 20

Indirect- transferred via blood transfusion, needlesticks/improper sterilized equipment

Direct- contaminated blood of person contacts another person with broken skin (mucous membrane/crossing placental barrier)