Chapter 2: The Dynamics of Disease Transmission

Question 1

What does the epi triangle consist of?

Answer 1

Consist of host (who), agent (how), environment (where), vector/time.

Question 2

What are the factors for Host?

Answer 2

• Age
• Sex
• Race
• Occupation
• Genetics

Question 3

What are the factors for Agent?

Answer 3

• Bacteria
• Viruses
• Chemicals
• Injury

Question 4

What are the factors for Environment?

Answer 4

• Pollution
• Noise
• Overpopulation
• Safety conditions

Question 5

What are the factors for Vector/Time?

Answer 5

Vector:
- Person
- Animal
- Microorganisms
Time:
- Duration of the illness
- The amount of time person is sick before death or recovery incubation period

Question 6

What is vector (living)?

Answer 6

an invertebrate animal (tick, mosquito without a backbone) capable of transmitting an infectious agent among vertebrates (animals/humans with backbone)

Question 7

How can vectors be spread?

Answer 7

a vector can be spread from an infected animal or human to humans or animals, and through waste products, bite, body fluids or indirectly through food contamination.

Question 8

Epidemic

Answer 8

health-related state or event in a defined population above the expected over a given period of time. (Widespread occurrence of disease within a community/ region)

Question 9

Endemic

Answer 9

is the habitual presence of a disease within a given geographic area. (regularly occurrence of a given disease)

Question 10

Pandemic

Answer 10

a worldwide epidemic. (Epidemic affecting a large number of people in many countries, continents, or regions)

Question 11

Can an epidemic be stopped if the elements of the epi triangle are interfered with. True or false

Answer 11

True

Question 12

What does the chain of infection consist of

Answer 12

microorganisms, reservoir, port of exit, modes of transport, port of entry, susceptible host.

Question 13

What are disease-causing microorganisms?

Answer 13

• Bacteria
• Viruses
• Fungi
• Parasites

Question 14

Reservoirs (alive)

Answer 14

are the environments or habitats in which disease-causing agents reside, grow, and multiply.

Question 15

What are examples of reservoirs?

Answer 15

• Humans
• Animals
• Soils
• Water

Question 16

Fomite (unalive)

Answer 16

is an object capable of transmitting infectious disease, through doorknob, computer, or a computer mouse.

Question 17

Portal of exit

Answer 17

is the way through which the disease-causing agent exits or leaves the reservoir.

Question 18

Where can the disease-causing agent exit through the reserviors?

Answer 18

• Skin to skin contact
• Skin to surface contact
• Saliva
• Blood

Question 19

Modes of transport

Answer 19

are how pathogens move from reservoirs to susceptible hosts, through transport either through direct or indirect transport.

Question 20

Modes of disease transmission

Answer 20

Direct (person-to-person) ex: sexual transmitted infections
Indirect (Common vehicle: single exposure, multiple exposures, continuous exposure/ vector) ex: contaminated water or air

Question 21

Portal of entry

Answer 21

is the way through which the disease-causing agent enters the body of the susceptible host.

Question 22

What are examples of portal of entry?

Answer 22

• Mouth
• Eyes
• Urinary Tract
• Wounds

Question 23

susceptible host

Answer 23

is the person/ animal at risk for contracting a disease.

Question 24

What are factors that makes a person susceptibility?

Answer 24

• Age
• Co-morbidities
• Medications
• Immunity
• Occupations

Question 25

What is susceptibility?

Answer 25

is the predisposition, sensitivity to, or ability to resist a disease.

Question 26

Subclinical disease

Answer 26

(internally developing)- disease that is not clinically apparent and is not destined to become clinically apparent. (need further testing)

Question 27

Clinical disease

Answer 27

(externally developing) is characterized by signs and symptoms.

Question 28

Pre-clinical disease

Answer 28

disease that is not yet clinically apparent but is destined to progress to clinical disease.

Question 29

Chronic disease

Answer 29

a person fails to shake off the infection, and it persists for years, at times for life.

Question 30

Latent disease

Answer 30

an infection with no active multiplication of the agent, as when viral nucleic acid is incorporated into the nucleus of a cell as a provirus. (disease that is present within a person but is inactive/hidden)

Question 31

Carrier

Answer 31

harbors the infectious agent but does not demonstrate clinical symptoms of disease. ex: Typhoid Mary a long-time carrier who showed no symptoms but infected many.

Question 32

Incubation period

Answer 32

the period of a disease is the period that spans between when a host is infected and when they start showing signs of disease.

Question 33

Immunity

Answer 33

someone who has been immunized or developed antibodies from previously having the disease.

Question 34

Natural immunity (active immunity)

Answer 34

acquired through exposure to a disease-causing organism.

Question 35

Vaccine- induced community (active immunity)

Answer 35

acquired through the introduction of a killed or weakened form of the disease organism through vaccination.

Question 36

Passive immunity

Answer 36

acquired when a person is given antibodies rather than producing them through their own immune response.

Question 37

Passive immunity lasts only for a few weeks or month true or false?

Answer 37

True

Question 38

Active immunity is long-lasting true or false.

Answer 38

True

Question 39

It takes active immunity a month to develop true or false.

Answer 39

False it takes usually weeks to develop active immunity.

Question 40

What is herd immunity?

Answer 40

the resistance of a group of people to an attack by a disease to which a large proportion of the members of the group are immune. (makes it harder for a disease to spread within a community)