How do plagues spread?

Question 1

how do religion and taboo influence ideas of disease and vice versa?

Answer 1

rise of large contemporary religions occurred during rise of cities, potentially during times of plague.
food prohibitions may have developed as strategy for reducing risk of pathogen exposure.
ex. pork is not kosher or halal- tricinosis are worms found in pork muscle and can’t be cooked out.

there is a strong correlation between disease richness and number of religions in an area

Question 2

the humoral theory of disease

Answer 2

incorrect balancing of humours led to disease
no understanding of infection
blood, phlegm, black bile and yellow bile

Question 3

miasma theory of disease

Answer 3

bad air causes disease
bad smells

Question 4

how did the scientific revolution change the theories surrounding disease?

Answer 4

Robert Koch stressed disease specificity: where one microorganism causes one disease
framework- the pathogen as the disease causing agent

Question 5

describe the germ theory of disease

Answer 5

microorganisms/pathogens/germs cause disease. these small microorganisms are too small to be seen without magnification. they can invade humans, other animals and other living hosts. their growth and reproduction within their hosts can cause disease.
Contributions made by Pasteur, Lister and Koch

Question 6

Louis Pasteur contributions

Answer 6

shows existence of microorganisms, thus demonstrating the utility of germ theory

Question 7

Joseph Lister contributions

Answer 7

applied Pasteur’s microbiology to produce antiseptics and discredit the idea of miasma causing infectious disease

Question 8

Robert Koch contributions

Answer 8

discovered cholera bacteria
Koch’s Postulates

Question 9

What are Koch’s Postulates?

Answer 9

1. the microorganism must be found in abundance in all organisms with the disease but should not be found in healthy organisms
2. the microorganism must be isolated from a diseased organism and grown in pure culture
3. the cultured microorganism should cause disease when introduced into a healthy organism
4. the microorganism must be re-isolated from the inoculated, diseased experimental host and identified as being identical to specific causative agent

Question 10

Who is the father of epidemiology?

Answer 10

John Snow
mapped the london cholera outbreak of 1848

Question 11

what is epidemiology

Answer 11

the study of patterns, causes, and effects of health and disease conditions in defined populations

Question 12

pathogen

Answer 12

anything that produces disease

Question 13

microorganism

Answer 13

living creatures (plant or animal) visible with a microscope

Question 14

microscopic

Answer 14

invisible to the eye

Question 15

macroscopic

Answer 15

visible without a microscope

Question 16

symbiotic relationship

Answer 16

microorganism and host benefit

Question 17

commensal relationship

Answer 17

one benefits without damaging the other

Question 18

parasitic relationship

Answer 18

one befits at other’s expense

Question 19

what sort of relationship is seen in disease?

Answer 19

parasitism, or commensalism gone wrong

Question 20

types of pathogenic microorganisms

Answer 20

bacteria
virus
fungi
protozoa

Question 21

bacteria

Answer 21

single celled fast growing organisms

Question 22

shapes of bacteria

Answer 22

coccus= sphere
bacillus = rod
vibrio = curved
spirillum and spirochetre = spiral

strepto__ = chain of ____

Question 23

true or false: most bacteria are pathogens

Answer 23

false

Question 24

carrier state

Answer 24

appearance of an organism of relatively high pathogenicity in the normal flora without causing disease

Question 25

how can bacterial disease come about?

Answer 25

some bacteria are entirely adapted to be pathogens and never occur in normal flora (TB, plague)

some bacteria are part of normal flora that become virulent and pathogenic (E.Coli)

some bacteria from normal flora cause disease if they gain access to deep tissues

immunocompromised patients, normal flora causes disease especially in deep tissues

Question 26

viruses

Answer 26

microscopic organisms that can infect hosts
small pieces of genetic information inside a capsid shell or envelope.
cant reproduce without a host

viruses are smaller than bacteria
have no nucleus or cell wall
have a simpler genome
antibiotics DO NOT WORK

Question 27

which of the following is enveloped: bacteriophage or influenza

Answer 27

influenza

Question 28

fungi

Answer 28

yeasts and molds
relatively few fungal diseases are pathogenic to humans

Question 29

protozoa

Answer 29

single celled with complex life cycle, many stages

Question 30

what species is greatest source of infection for humans?

Answer 30

humans

Question 31

modes of direct transmission

Answer 31

direct contact
respiratory
fecal-oral
sexual contact
forties

Question 32

direct contact transmission

Answer 32

direct person-person contact
contact with contaminated skin (hands), saliva, respiratory secretions, blood

Question 33

respiratory transmission

Answer 33

spread through droplets and inhaled via coughing, sneezing, laughing, and close contact
aerosols within + beyond 1m
droplets less than 1m

Question 34

fecal oral

Answer 34

germs found in feces of infected person are spread to another person
person touches stool of infected person, or ingests something contaminated with infected feces

Question 35

sexual contact transmission

Answer 35

STIs can be bacteria, viruses or parasites
may pass through blood, semen, vaginal or other bodily fluids

Question 36

fomites transmission

Answer 36

non living object that transmits disease
door handles, phones, desktops, buttons

Question 37

zoonosis

Answer 37

an infectious disease transmitted to humans from non human reservoir

there are often “spillover” infections. which are incidental infections that fail to produce sustained epidemics in new hosts
reservoir host: natural host in which pathogen is endemic or epidemic

Question 38

host jumping

Answer 38

when an infectious disease causes sustained infection in a novel host species

Question 39

emerging disease

Answer 39

an infectious disease whose incidence has increased precipitously in recent past

Question 40

vector

Answer 40

any intermediary agent that passes pathogens to another individual

Question 41

zoonosis stages

Answer 41

1. animal only: microbe present in animals has not been found in humans
2. primary infection: pathogen that under natural conditions can be transmitted from animal to human but not transmitted between humans (ex. rabies)
3. limited outbreak: animal pathogen can undergo few cycles of secondary transmission in humans, but occasional human outbreaks eventually die out
4. long outbreak: disease exists in animals, and can also infect humans by primary transition form animal host, and has long sequences of secondary transmission between humans without need of animal hosts
5. exclusive human agent: pathogen exclusive to humans

Question 42

what 3 things control disease emergence? describe them

Answer 42

ecological factors
- proximity of donor and recipient populations
-size/density of donor and recipient populations

genetic factors
- effectiveness of immune response in clearing pathogen
- ability to recognize and replicate in host cells
- variation and adaptability to pathogens

overall patterns
- generally, cross species transmissions are less likely among phylogenetically divergent hosts
- most cases of emergence are spillovers with no onward transmission