Lecture 36/37/38 Epidemiology

Question 1

Epidemiology

Answer 1

the study of the occurrence, distribution, and determinants of health and disease in a population and the application of this study in the control of health problems

Question 2

What do epidemiologists do?

Answer 2

trace the spread of disease to identify its origin and mode of transmission

Question 3

What types of data do epidemiologists collect on populations?

Answer 3

demographics, symptoms, history, animal vector data, medical records, etc

Question 4

When did epidemiology start?

Answer 4

mid-1880s

Question 5

Ignaz Semmelweis

Answer 5

“Savior of Mothers”; implemented handwashing wtih chlorinated lime solutions

Question 6

Florence Nightingale

Answer 6

nurse and statistician; sent to Ukraine to report conditions of infection during the war

Question 7

John Snow

Answer 7

“Father of Epidemiology”; british physician in the 1850s that pioneered epidemiological investigations and disease mapping

Question 8

Why were Nightingale’s Rose diagrams significant?

Answer 8

provided a visual that was easier to understand than charts

Question 9

Epidemic

Answer 9

when as disease occurs in an unusually high number of individuals in a population at the same time

Question 10

What did John Snow do in the 1850s?

Answer 10

traced the source of an outbreak of Cholera to a water pump on Broad St.

Question 11

Where there other people investigating this cholera outbreak at the same time?

Answer 11

Yes; for example, Edmund Cooper and the British Empire

Question 12

Endemic

Answer 12

normal rates of disease that is expected in a population

Question 13

Endemic Disease

Answer 13

constantly present, occurs at a steady low frequency with predictable changes

Question 14

Epidemic Disease

Answer 14

sudden increase in occurrence of disease above expencted levels

Question 15

Example of an endemic disease

Answer 15

the common cold

Question 16

Example of an epidemic disease

Answer 16

cholera

Question 17

Pandemic disease

Answer 17

increase in a disease through large populations and across continents

Question 18

Example of a pandemic disease

Answer 18

plague, AIDS, covid-19

Question 19

Significance of understanding the chain of infection

Answer 19

helps us develop strategies to prevent further infection and to control disease

Question 20

What is the chain of infection?

Answer 20

1) the pathogen
2) source of pathogen
3) transmission to host
4) susceptibility of the host
5) exit from host

Question 21

Etiological agent

Answer 21

the organisms that causes disease

Question 22

What do you use to identify the etiological agent?

Answer 22

Kock’s postualtes

Question 23

Examples of biological agents of disease

Answer 23

metazoans, protozoans, fungi, bacteria, viruses, prions

Question 24

Reserviours

Answer 24

the site or natural environment where the pathogen is normally found living and from which infection can occur

Question 25

What are the two types of human reservoirs?

Answer 25

acute clinical cases and carriers

Question 26

Incubatory carriers

Answer 26

just get sick and recover

Question 27

Convalescent carriers

Answer 27

recover but still shed disease

Question 28

Chronic carriers

Answer 28

sick and shed disease

Question 29

Asymptomatic

Answer 29

no symptoms and shed disease

Question 30

True or False: there are many kinds of animal reservoirs

Answer 30

True!

Question 31

Zoonotic infection

Answer 31

infectious disease originating from animals, can be transmitted from one type of animal to another and may be transmitted to humans

Question 32

Examples of zoonotic infection

Answer 32

plague, rabies, west nile, monkeypox

Question 33

Examples of environmental reservoirs

Answer 33

plants, soil, watr

Question 34

Can you easily get rid of pathogens in environmental reserviours?

Answer 34

No!

Question 35

Direct transmission

Answer 35

an infectious agent is transferred from a reservoir to a susceptible host by direct contact or droplet spread

Question 36

Indirect transmission

Answer 36

the transfer of an infectious agent from reservoir to a host by suspended air particles, inanimate objects, or animate intermediaries

Question 37

What are animate intermediaries called?

Answer 37

vectors

Question 38

What are inanimate objects called?

Answer 38

vehicles

Question 39

What four things impact host susceptibility?

Answer 39

1) genetic factors 2) general resistance factors 3) specific acquired immunity 4) host variability (timing)

Question 40

What are five things that impact host variability?

Answer 40

1) nutrition 2) stress levels 3) physical damage to tissue 4) behavioral differences 5) environmental conditions

Question 41

What are some ways in which a pathogen can exit from a host?

Answer 41

coughing, insect bite, removal of blood, skin cells, urine, feces

Question 42

What are the Cholera Stages of Disease?

Answer 42

1) incubation period 2) prodromal period 3) period of illness 4) period of decline 5) period of convalescence

Question 43

Incubation period

Answer 43

no signs or symptoms; few hours to few days

Question 44

Prodromal period

Answer 44

mild signs/symptoms; 1-2 days if any

Question 45

Period of illness

Answer 45

disease most severe; symptoms of diarrhea, nausea, vomiting

Question 46

Period of decline

Answer 46

signs and symptoms subside; decreased diarrhea; begin response to rehydration therapy and antibiotic treatment

Question 47

Period of convalescence

Answer 47

person regains strengths and the body returns to normal; some people can become reservoirs of disease for months or even years

Question 48

Who is most at risk of contracting cholera?

Answer 48

those who do not have access to piped safe water and adequate and proper sanitation

Question 49

Period of communicabiltiy

Answer 49

the time in which an infectious disease might be transferred

Question 50

What is the period of communicability for cholera?

Answer 50

the duration of the stool-positive stage; can persist for several months

Question 51

Infective dose

Answer 51

the number of pathogens required to infect a host

Question 52

Index/primary case

Answer 52

the person who first gets the disease in a population

Question 53

Common sources for infection of cholera?

Answer 53

contaminated water, contaminated foods, vegetables fertilized with human excreta, soiled hands, fish/shellfish eaten raw

Question 54

Herd immunity

Answer 54

immunity in some individuals from vaccinations or naturally acquired can protect non-immune individuals from infection

Question 55

Host variability factors for cholera

Answer 55

1) poor sanitary conditions 2) raw or undercooked shellfish 3) reduced or nonexistent stomach acid 4) household exposure 5) type O blood

Question 56

What are three epidemic control measures for cholera in Haiti?

Answer 56

1) proper sanitation 2) sterilization of waste 3) quarantine 4) destruction of domestic animal reservoirs 5) immunization 6) public health education 7) increased accessibility to treatment