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YR 12 BIO > MODULE 7. INFECTIOUS DISEASE > Flashcards

MODULE 7. INFECTIOUS DISEASE Flashcards

1
Q

what is an infectious disease

A

INFECTIOUS DISEASE = Disease which can be transmitted from one organism to another, and are caused by pathogens.

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2
Q

what is a pathogen

A

PATHOGEN = Any organism which is capable of causing disease

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3
Q

list the types of different pathogens from smallest to largest

A 
bacteria
fungi
protozoa
virsuses
prions
parasites
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4
Q

how is bacteria characterised

A

prokaryotic unicellular organisms which don’t have membrane bound organelles and are made of one cell

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5
Q

how can bacteria cause disease

A

by releasing toxins or damaging host tissues

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6
Q

e.g. of bacteria

A

tuberculosis

- caused by mycobacterium tuberculosis that enters the lungs when a person inhales infectious droplets

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7
Q

how is fungi characterised

A
  • Eukaryotic, non-photosynthetic, heterotrophic organisms with a cell wall. Can be either unicellular or multicellular
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8
Q

how does fungi cause disease

A
  • The damage caused by fungi mostly arises from the enzymes they produce.
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9
Q

e.g. fungal disease

A

tinea
Mode of transmission = direct contact, skin to skin contact, surfaces e.g. shower floor
- The fungi lives in the outside layer of human skin, where they produce chemicals which break down keratin
- Symptoms include itchiness, inflammation and flaky skin

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10
Q

how is protozoans characterised

A
  • Unicellular microorganisms with internal membranes. Eukaryotic with a complex lifestyle.
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11
Q

e.g. protozoans

A

• E.G. MALARIA

  • Caused by plasmodium
  • Plasmodium floats freely in the blood of an infected person
  • It feeds on haemoglobin in the red blood cells causing them to pop
  • Symptoms include fever, nausea, muscle pain and headaches
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12
Q

how are viruses characterised

A
  • Non-cellular entities (not living), consisting of a single type of nucleic acid (DNA or RNA) encased in a protein coat.
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13
Q

how does viruses cause disease

A
  • Needs a host cell to reproduce  The virus attaches to a host cell, which it then penetrates. It hijacks the hots enzymes and nutrients to make its own viral proteins and nucleic acid
  • The viral materials assemble into new viruses which are released from the host cell and infects other cells
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14
Q

e.g. virus

A

influenza

covid19

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15
Q

how are prions characterised

A
  • Protein that has been altered from its normal structure and can then alter other proteins to develop more prions, so that the change spread like a chain reaction.
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16
Q

e.g. prions

A

SPONGIFORM ENCEPHALOPATHY IN CATTLE (MAD COW DISEASE)

  • Progressive, degenerative and fatal disease affecting the central nervous system in cattle
  • The human form is called Creutzfeldt-Jakob disease (vCJD)
  • Symptoms include loss of intellect and memory, changes in personality, loss of co-ordination, slurred speech, vision problems and blindness.
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17
Q

define outbreak

A

where the disease pops up temporialiy in an isolated area

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18
Q

define endemic level

A

people affected by the disease at any given time

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19
Q

define pandemic

A

an increase in the number of cases throughout a continent or across the world

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20
Q

what are the two levels that contribute to epidemics

A

pathogen level

human level

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21
Q

what are factors that contribute to epidemics at a pathogen level

A 
virulence
antibiotic resistance
toxins
genetic shift
herd immunity
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22
Q

how does virulence contribute to epidemics @ a pathogen level

A

Pathogens ability to infect or damage a host

  • The greater the virulence the greater effect it will have on the health of the host
  • Mutations increase a pathogens virulence, allowing it to evade detection in hosts
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23
Q

how does antibiotic resistance contribute to epidemics @ a pathogen level

A

Antibiotic resistant pathogens can’t be treated and are spread more easily.

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24
Q

how does toxins contribute to epidemics @ a pathogen level

A
  • Make host more susceptible to infection

- Deter other pathogens

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25
Q

how does genetic shift contribute to epidemics @ a pathogen level

A
  • Can occur if there is a loss of genetic variation or selection pressures that cause the population to lose genetic resistance
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26
Q

how does herd immunity contribute to epidemics @ a pathogen level

A
  • In populations where a significant proportion of individuals are immune, the group becomes immune
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27
Q

how does migration contribute to epidemics @ a human level

A
  • People can be disease vectors, so movement between different groups increases the chances of disease being transmitted between them
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28
Q

how does infrastructure contribute to epidemics @ a human level

A
  • When populations are densely packed together, increased exposure to pathogens is likely
  • Lack of amenities like clean running water, effective sewage systems and adequate health services promote disease survival
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29
Q

how does health care contribute to epidemics @ a human level

A
  • Disease spread is increased where people do not have access to drugs and vaccines
    1. Instructure is lacking, so clinics are not accessible
    2. High cost of medicine
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30
Q

what are the three ways to control an epidemic

A
  1. identifying the pathogen
  2. environmental management
  3. quarantine
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31
Q

how does identifying the pathogen contribute to controlling an epidemic

A

Health workers help identify disease through:

a. Clinical observation
b. Laboratory confirmation
c. Data is collected on the number of cases presented and fed into larger surveillance systems

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32
Q

how does environmental management contribute to controlling an epidemic

A
  1. Cleansing water supplies of disease
    - e.g. boiling, chlorinating, sealing
  2. Reducing the risk of food contamination
    - e.g. limiting food preparation, disposing of old food.
  3. Creating sanitary conditions
    - e.g. removing waste from public areas, providing sealed sewage systems
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33
Q

how does quarantine contribute to controlling an epidemic

A

A period of restricted movement and separation of people, animals and materials which may spread infectious disease
LARGE scale = travel bans, border regulation
SMALL scale = protective clothing, isolation

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34
Q

what is direct contact

A
  1. DIRECT CONTACT = physical contact between an infected organism and a susceptible organism allows the transfer of infected bodily fluids.
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35
Q

what is indirect contact

A
  1. INDIRECT CONTACT = Infectious diseases can also be spread indirectly through the air and other mechanisms.
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36
Q

what are the two ways direct contact can cause disease

A

person to person contact

droplet spread

37
Q

disease e.g.s from person to person contact

A

STDs
ring worm
needle injections

38
Q

how does person to person contact occur

A

shaking hands
touching
sex

39
Q

how does droplet spread occur

A

when a person breathes talks coughs or sneezes

40
Q

e.g. of direct contact

A

tuberculosis

41
Q

what ways can indirect contact occur

A

airborne transmission
contaminated object (fomites)
contaminated food and water (vehicular)

42
Q

how does airborne transmission occur

A

Some infectious agents can travel long distances and remain suspended in the air for an extended period of time.

43
Q

how does fomites occur

A

Some organisms can live on objects for a short time. If you touch an object, such as a door knob, soon after an infected person, you might be exposed to infection. Transmission occurs when you touch your mouth, nose, or eyes before thoroughly washing your hands.

44
Q

how can vehicular transmission occur

A

Infectious diseases can be transmitted via contaminated food and water,
E.G. E. coli is often transmitted through improperly handled produce or undercooked meat

45
Q

how does vector borne disease occur

A
  1. VECTOR BORNE DISEASE (INSECT BITES) = Infectious diseases can also be spread indirectly through the air and other mechanisms.
46
Q

e.g. of vector borne diseases

A

E.G. malaria  Caused by a protist called plasmodium. The plasmodium pathogen floats in the blood of an infected person and feeds on haemoglobin causing red blood cells to pop.
Symptoms: Fever, muscle pain, nausea, headaches, weakness
When the female mosquito bites an infected person the pathogen is taken up with the blood

47
Q

how did koch build on germ theory

A

koch isolated and grew the bacteria responsible for causing anthrax

48
Q

what did koch discover

A

kochs postulates

49
Q

what are kochs postulates

A

KOCH’s POSTULATES = list of criteria which must be met to prove that a particular organism causes a particular disease.

50
Q

list kochs postulates

A
  1. The suspected pathogen must be present in every diseased individual, and absent in healthy individuals.
  2. The suspected pathogen must be able to be isolated from the host and grown in pure culture.
  3. A healthy potential host must develop the same symptoms as the original host, when inoculated with the suspected pathogen (essentially the disease must be able to reproduced)
  4. The suspected pathogen must be re-isolated from the second host and grown in pure culture, appearing identical to the original culture (essentially, the organism must be re-isolated)
51
Q

how did louis pasteur build on the microbial fermentation theory

A
  • In 1857, Pasteur discovered that sour wine contained two types of microorganisms. One of was yeast which he discovered was responsible for fermenting sugars to make alcohol. This resulted in the idea that fermentation is caused by microbes, known as the microbial fermentation theory.
52
Q

what is pasteurisation

A

Pasteurisation was on the principle that heating liquids to 60-100oC would kill most microbes, and was so effective that Pasteur recommended the process for the sterilisation of objects as well as liquids e.g. beer, wine, milk…

53
Q

what is louis pasteurs proof on germ theory

A

Pasteur proved the germ theory of disease (which states that many diseases are caused by the presence and actions of specific microorganisms within the body) using his swan-neck flask experiment. • Swan neck flask - Broth placed in swan neck flask, boiled to get rid of micro-organisms, one flask was broken, and one was normal. Broken one had spoiled (proves that bacteria don’t just generate randomly, they come from exposure to the air)
In doing so, he disproved the theory of spontaneous generation.

54
Q

what are the causes of plant diseases

A

infectious agents

abiotic factors

55
Q

what are the effects of plant diseases

A

o Infectious diseases impede a plants ability to function normally and therefore has a significant impact on the yield and quality
o Plant diseases cost millions each year and impacts our ability to trade (locally and internationally)
o It is estimated that pathogens cause 12.5% crop loss globally
o Significant social impacts (potato famine of 1845-1849)
o Adverse effect on biodiversity in natural ecosystems.

56
Q

what are causes of disease in animals

A

infectious agents

57
Q

effects of animal diseases

A

economic - food security…

health risks - potenial risk to infect humans

58
Q

prevention control and treatment: what does local factors refer to

A

usually related to a neighbourhood, town or city

59
Q

what are hygiene practices used for

A

prevention

60
Q

what does hygiene practices entail

A

personal level
government regulations
safe food practices

61
Q

hygiene pracitces at a personal level

A

cleaning:

  • yourself
  • clothing
  • surroundings
  • using contraceptives
62
Q

hygiene: gov regulations

A
  • collection and disposal of waste

- the provision of access to clean water (filtered, chlorinated, tested)

63
Q

hygiene practices: safe food practices

A
  • wearing gloves

- properly cleaning surfaces when preparing food

64
Q

what is quarantine

A

a period of isolation used to control the spread of infectious disease

65
Q

what scales does quarantine involve

A

small scale

large scale

66
Q

quarantine: small scale

A

confining patients

  • to their homes
  • to their hospital beds
67
Q

quarantine: large scale

A

o Confining whole communities
- Schools and work places closed
- Borders cut off and patrolled with strict exit/entry criteria based on health
o Goods and transport
- Banning the movement of fruits across borders to protect against fruit flies

68
Q

what does vaccines provide individuals with

A

artificial active immunity

69
Q

why are vaccines used

A

prevent

70
Q

why is quarantine used

A

to control

71
Q

why are public health campaigns used

A

prevention and control

72
Q

what are pesticides

A

substances which control pest

73
Q

what is the human benefit of using pesticides

A 
o	Protecting against:
-	Vector-borne diseases
-	Crop 
-	Livestock
o	Defends the health of communities by sustain their food source
74
Q

dangers of using pesticides

A

Biomagnification: Pesticide accumulates in the body tissues of organisms in the food chain in increasing amounts of higher trophic levels.
Resistance: Overuse of pesticides promotes the selection of naturally resistant strains

75
Q

why is genetic engineering used

A

to modify the genetic structure of an organism

76
Q

why is genetic engineering used to prevent disease

A

Used to produce plants and animals which are resistant to pests and disease

  1. To disable vectors from spreading disease
  2. To modify animals to produce biomedical products.
77
Q

what are antivirals

A

drugs that treat viral infections

78
Q

how are antivirals used

A
  1. Prevent viruses entering host cells by binding to receptors
  2. Inhibiting enzymes which catalyse the reproduction of the viral genome(preventing viral replication)
  3. Blocking transcription and translation of viral proteins – since they don’t have ribosomes, viruses need to use the ribosomes of a host cell to make their protein coat
  4. Preventing a virus from leaving the cell
  5. Grabbing the virus whilst outside the cell by targeting capsid proteins
79
Q

what are antibiotics

A

drugs that treat bacterial infections

80
Q

what are ways antibiotics work

A

killing bacteria causing the disease

slowing of the growth bacteria, giving the immune system a greater change of being able to remvoe it

81
Q

e.g. of antibiotics

A

penicillin

82
Q

how does penicillin work

A

o Causes the bacterial cell walls to weaken, resulting in the death of the cell

83
Q

how does antibiotic resitance happen

A

through mutation

84
Q

what is dengue fever

A

mosquito borne tropical disease caused by dengue virus

85
Q

incidence of dengue fever

A

390 mil/year - globally

86
Q

mortality of dengue fever

A

22mil/year - globally

87
Q

define bush medicine

A

• A term used to describe the skills and practices used to maintain health, based on indigenous beliefs and practices.

88
Q

e.g. of bush medicine

A

tea tree oil

eucalptus oil

YR 12 BIO (10 decks)

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