Concepts of Disease Occurrence and the Natural History and Spectrum of Disease

Question 1

agent

Answer 1

referred to an infectious microorganism or pathogen a virus bacterium, parasite or other microbe, chemical and physical causes of diseas

basically anythiing that can couse disease

Question 2

pathogenicity

Answer 2

ability to cause disease

Question 3

host

Answer 3

the human who can get the disease

Question 4

environment

Answer 4

extrinsic (external) factors that affect the agent and the opportunity for exposure

physical factors (geology and climate)
biologic factors (insects that transmit the agent)
socieconomic factors

Question 5

Causal pies WHO? WHEN?

Answer 5

Rothman 1976

Question 6

causal pies

Answer 6

made up of component causes, when it comes together you can get a disease

Question 7

the complete pie

Answer 7

called a causal pathway or a sufficient cause

can have multiple causal pathways

Question 8

necessary cause

Answer 8

appears in every pie or pathway, without disease does not occur

Question 9

Natural history of disease

Answer 9

refers to the progression of a disease process in an individual over time, IN THE ABSENCE OF TREATMENT

Question 10

Step 1 in Natural History

Answer 10

exposure to accumulation of factors

Question 11

Step 2 in Natural History of a Disease

Answer 11

Incubation/Latency Period

• pathological changes without the individual being aware
• the time of exposure to onset of disease symptoms

Question 12

incubation period is for

Answer 12

infectious disaeses

Question 13

latency period for

Answer 13

chronic diseases

Question 14

What is Step 3 in Natural History

Answer 14

Onset of Symptoms

• transition from subclinical to clinical disease
• most diagnoses are made during this stage

Question 15

spectrum of disease

Answer 15

the severity of disease mild to severely fatal

Question 16

3 possible endings of a disease

Answer 16

• recovery
• disability
• death

Question 17

Infectivity

Answer 17

proportion of exposed persons who became infected

Question 18

pathogenicity

Answer 18

proportion of infected individuals who develop clinically apparent disease

Question 19

virulence

Answer 19

the proportion of clinicaly apparent cases that are severe or fatal

Question 20

carriers

Answer 20

people who are infectious but have subclinical disease are called carriers

Question 21

Asymptomatic , passive, or healthy

Answer 21

those who never experience symptoms despite being infected

Question 22

incubatory carriers

Answer 22

those who can transmit the agent during the incubation period before clinical illness begins

Question 23

convalescent carriers

Answer 23

those who have been recovered from their illness but remain capable of transmitting to others

Question 24

Chronic carriers

Answer 24

those who continue to harbour a pathogen for months or even years after their initial infection

Question 26

Hosa id

Answer 26

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