16. Infectious Diseases Flashcards

1
Q

In what ways can an infectious disease be transmitted?

A

Human to human
Animal to human
Direct contact
Indirect contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What may diseases be caused by?

A

Micro-organisms (microbes)

Multi-cellular organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Examples of micro-organisms

A

Bacteria
Fungi
Protozoa
Viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the characteristics of micro-organisms?

A

Non-pathogenic

Pathogenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the characteristics of non-pathogenic micro-organisms?

A

Not disease causing

Many are symbiotic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the ratio of bacterial cells to human cells

A

10:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Examples of microbe relationships

A

Commensal
Mutualistic
Parasitic
Opportunistic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a commensal microbial relationship?

A

Symbiotic relationship between organisms

One benefits; the other is unaffected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Examples of commensal microbial relationships

A

Microbes on skin

Microbes in large intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a mutualistic microbial relationship?

A

Symbiotic relationship between organisms

Both benefit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Example of a mutualistic microbial relationship

A

E. coli make vit K for humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a parasitic microbial relationship?

A

Symbiotic relationship between organisms

One benefits but at the other’s expense

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Example of a parasitic microbial relationship

A

Head lice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is an opportunistic microbial relationship?

A

Symbiotic relationship between organisms

Initially commensal/mutualistic that becomes parasitic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Example of an opportunistic microbial relationship

A

Candida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What was Pasteur’s theory of microbes?

A

‘Germ theory of disease’

All germs are bad and cause disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What was Bechamp’s theory of microbes?

A

Germs are opportunistic in nature and live with us symbiotically
Terrain theory - the terrain provides the environment for bacteria to grow
Promote health through diet and exercise to promote healthy bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How can microbes be identified and characterised?

A

Cultured in lab
Light microscope
Electron microscope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which microbes can be seen under a light microscope?

A

Whole micro-organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which microbes can be seen under an electron microscope?

A

Viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the characteristics of bacteria?

A

Prokaryotic
No nucleus
No membrane-bound organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the control centre of bacteria?

A

Single loop of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What two types of cell wall can bacteria have?

A

Gram positive

Gram negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a gram positive cell wall?

A

Thick
Mesh like
Made from peptidoglycan (proteins/carbs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is a gram negative cell wall?

A

Thin

Additional outer lipid-rich membrane (fats/carbs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does the Gram staining method do?

A

Helps to understand category type of bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does the Gram staining method show?

A

Purple stain = gram positive

Pink stain = gram negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What shape is bacilli bacteria?

A

Rod-shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Example of bacilli bacteria

A

E. coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What shape is cocci bacteria?

A

Spherical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Example of cocci bacteria

A

Streptococci

Staphylococci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What shape is spirochetes bacteria?

A

Spiral-shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How do bacteria reproduce?

A

Binary fission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is binary fission?

A

Enables bacteria to reproduce in high numbers at a rapid rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is spore formation?

A

Structure extremely resistant to hostile physical and chemical conditions e.g. heat and disinfections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are invasive enzymes?

A

Enzymes produced by some bacteria to help them break down a host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are the characteristics of exotoxins?

A

Gram positive and negative
Released by a living microbe
Very toxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What are the characteristics of endotoxins?

A

Gram negative
Released after organism death from cell wall
Stimulates inflammatory cascade leading to fever, malaise
Usually less toxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Examples of an exotoxin

A

Diphtheria
E. coli
C. tetani

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Example of an endotoxin

A

Salmonella

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Where can microflora be found?

A
Skin
Nasal cavity
Mouth
Small/large intestine
Vagina
Perineum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Where is microflora absent?

A
Blood
CSF
Lungs
Stomach
Bladder/kidneys
Uterus/fallopian tubes/ovaries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What can make organisms within microflora become pathogenic?

A

If local environment changes

If immune system becomes compromised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are antibiotics?

A

Conventional drugs that destroy bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are the two groups of antibiotics?

A

Broad spectrum

Narrow spectrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What do broad spectrum antibiotics target?

A

Target any bacteria (including body’s healthy microflora)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What do narrow spectrum antibiotics target?

A

Only a small group of bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What are the issues with antibiotics?

A

Often overprescribed
Adverse effects
Antibiotic resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is higher antibiotic use linked to?

A

Higher risk of disease e.g. asthma, IBD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What don’t antibiotics help with?

A

Viruses e.g. cold, flu, cold sores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What are some of the adverse effects associated with antibiotic use?

A

Impaired immunity
Candida overgrowth
Diarrhoea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What are viruses?

A

Intracellular parasites that need a living host for survival and replication

53
Q

How is a virus structured?

A

Strand of DNA or RNA
Capsid (hard protein coat)
Envelope
Spikes (for attaching to specific cell surfaces)

54
Q

What is special about the capsid?

A

It’s unique for each virus

55
Q

Which are the smallest microbes?

A

Viruses

56
Q

How many virus microbes are said to fit on the head of a pin?

A

500 million

57
Q

What are the two types of viruses?

A

DNA virus

RNA virus

58
Q

Examples of DNA viruses

A

Varicella zoster
Herpes zoster
Smallpox

59
Q

Examples of RNA viruses

A

Measles
Mumps
HIV

60
Q

How do viruses reproduce?

A

By injecting their DNA/RNA strand into a living host cell and using the host cell’s apparatus for reproduction

61
Q

Can viruses infect any host cells?

A

No, they infect specific host cells due to surface spike proteins

62
Q

What happens when a virus binds with a cell?

A

It only allows entry of the genetic (DNA/RNA) material

Capsid remains outside

63
Q

What happens to the host cell once the virus leaves it?

A

It bursts (viral lysis)

64
Q

Why are viruses hard for the body and anti-viral drugs to identify and destroy?

A

They hide inside host cells
They don’t have a metabolism of their own
They don’t have many structures of their own
They are able to mutate (change their surface antigens)

65
Q

In what ways can viruses replicate?

A

Viral lysis
Viral budding
Latent stage

66
Q

What happens during viral lysis?

A

Virus particles burst out of the host cell into the extracellular space, killing the host cell

67
Q

What happens during viral budding?

A

Virus exits a cell by acquiring an envelope (outer membrane) of its own from the host cell membrane
Usually leads to host cell death

68
Q

What happens during the latent stage?

A

Disease is present but hidden and inactive

Can remain latent for years

69
Q

What are fungi?

A

Eukaryotic organisms

70
Q

What are the different ways fungi are structured?

A

Single-celled

Complex multicellular organisms

71
Q

What is found in the cell wall of fungi?

A

Melanin

72
Q

Where can fungi be found?

A

Soil
Mouldy bread
Medicine
Food

73
Q

What are filaments of fungi called?

A

Hyphae

74
Q

What is a mass of fungi filaments called?

A

Mycelium

75
Q

What are the characteristics of fungal infections?

A

Often opportunistic

Occur in immune-compromised patients e.g. HIV, diabetes mellitus

76
Q

What is a fungal infection also known as?

A

Mycosis

77
Q

What are the three types of fungi that usually cause infection?

A

Yeasts
Moulds
Dermatophytes

78
Q

What are yeasts?

A

Single-celled fungus

Reproduces through budding

79
Q

Example of a yeast

A

Candida albicans

80
Q

What are moulds?

A

Multi-cellular fungi
Some cause disease
Some are involved in the production of foods/antibiotics

81
Q

Examples of moulds

A

Aspergillus

Penicillium

82
Q

What are dermatophytes?

A

Fungi causing skin disease

83
Q

How do dermatophytes exist?

A

They obtain nutrients from keratin in skin and colonise the stratum corneum

84
Q

Examples of dermatophytes

A

Ringworm

Tinea

85
Q

What do fungi need to grow?

A

Warmth
Acidity
Rich nutrition
Moisture

86
Q

How do fungi reproduce?

A

Asexual reproduction

Sexual reproduction

87
Q

How does asexual reproduction occur among fungi?

A

Via budding

Hyphae extends containing chromatin and eventually detaches and develops into an independent organism

88
Q

How does sexual reproduction occur among fungi?

A

By forming fungal spores

89
Q

What are protozoa?

A

Single cell

Eukaryotic organisms

90
Q

What are the characteristics of protozoa?

A

Single-celled
No cell wall
Just a membrane

91
Q

Where can you find protozoa?

A

Moist environments such as:
Fresh water
Soils
Ocean

92
Q

How can protozoa move?

A

Flagella
Cilia
Vector

93
Q

How do protozoa reproduce?

A

Binary fission
Budding
Sexual reproduction
Cysts

94
Q

What are helminths?

A

Parasitic worms

95
Q

What are the characteristics of helminths?

A

Eukaryotic
Macroscopic
Multi-cellular

96
Q

What is the lifecycle of a helminth?

A

Egg
Larva
Adult

97
Q

Where can helminths live?

A

Blood
Intestines
Tissue

98
Q

Examples of helminths

A

Pinworm
Roundworm
Tapeworm

99
Q

What are most helminths?

A

Intestinal parasites

100
Q

Definition of ‘infection’

A

Invasion of a host by a pathogen causing disease

101
Q

What are the categories of where infections may occur?

A

Single individuals
Large groups
Worldwide
Restricted to an area

102
Q

What is an infection in large groups called?

A

Epidemic

103
Q

What is an infection worldwide called?

A

Pandemic

104
Q

What is an infection restricted to an area called?

A

Endemic

105
Q

What is a reservoir?

A

Location where the pathogen exists, reproduces and spreads to new hosts

106
Q

What is a carrier?

A

Infected individuals who are asymptomatic

107
Q

What is a vector?

A

Intermediate carrier, transporting pathogens from reservoir to host e.g. mosquito with malaria

108
Q

What is a host?

A

Infected person or animal e.g. mosquito

109
Q

How can infections be transmitted?

A
Droplets
Direct contact
Indirect contact
Vectors
Nosocomial
110
Q

Examples of droplet transmission

A

Coughing with flu, COVID, scarlet fever

111
Q

Examples of direct contact

A

Faeces

Another individual

112
Q

Examples of indirect contact

A

Food
Public transport
Toys

113
Q

Examples of nosocomial

A

Hospital setting

Care facility

114
Q

How can infections be acquired?

A
Ingestion
Direct to blood stream e.g. injection, open wound
Sexual intercourse
Inhalation
Touch
Placental
115
Q

What are the four stages of infection?

A

Incubation period
Prodromal period
Acute period
Chronic infection

116
Q

What is the incubation period?

A

Time interval between initial exposure to the infecting organism and the appearance of the first signs or symptoms

117
Q

What is the prodromal period?

A

Interval between non-specific symptoms (malaise, fever, fatigue) to more specific acute symptoms

118
Q

What is the acute period?

A

Pathogen peaks in population

Very pronounced symptoms specific to the disease

119
Q

What is a chronic infection?

A

Infection with insidious or slow onset of long duration

120
Q

How does a host resist an infection?

A
Intact skin and mucous membranes
Body secretions - stomach acid, tears, saliva
Phagocytosis
Interferon production
Effective inflammatory response
Effective immune system
121
Q

How does a microbe infect a host?

A
Production of invasive enzymes
Production of endo- or exo- toxins
Spore formation
Forming colonies
Presence of bacterial capsule and pili
Mutation
122
Q

What ways can be used to control infection?

A
Reduce the reservoir
Stop droplet transmission - cover mouth
Block the method of transmission - wash hands, gloves
Kill the organism
Sterilisation
123
Q

What are the best forms of reducing the number of organisms?

A

Sterilisation
Disinfectants
Antiseptics
Pasteurisation

124
Q

What is sterilisation and what does it do?

A

All micro-organisms and spores are destroyed

Hot air: 30 mins at 180C

125
Q

What does disinfectant do?

A

Destroys pathogenic microbes

Not spores

126
Q

What does antiseptic do?

A

Reduces number of organisms on the skin

Not spores

127
Q

What is pasteurisation and what does it do?

A

Kills most pathogenic microbes
Not spores
71.7C for 15-20 secs

128
Q

What are natural forms of infection control?

A
Tea tree oil
Eucalyptus oil
Neem oil
Calendula
Colloidal silver