Module Seven - Infectious Disease Flashcards
Causes of Infectious Disease Responses to Pathogens Prevention, Treatment and Control (183 cards)
1
Q
What is an infectious disease?
A
- They are diseases caused by pathogens
- Communicable or contagious diseases are infectious diseases that can spread from one organism to another by direct or indirect transmission.
2
Q
What is an infection?
A
It is the entry of a pathogen into body tissues and cells followed by multiplication of the organism.
3
Q
What is a pathogen?
A
- Pathogens are any organism living in or on another organism that is capable of causing disease.
4
Q
Types of pathogens: (size order)
A
- prions
- viruses
- bacteria
- protists (protozoa)
- fungi
- macroscopic parasitic animals (macroparasites)
5
Q
What are the distinguishing features of a prion?
A
- defective from of a protein molecule
- does not contain RNA or DNA
- mostly attacks brain or nerve cells
6
Q
What are the distinguishing features of a virus?
A
- non-cellular
- contains DNA, RNA and protein coat
- requires a living host cell to replicate
7
Q
What are the distinguishing features of a bacteria?
A
- prokaryotic cell
- divides quickly and/or produces toxins
8
Q
What are the distinguishing features of a protozoan?
A
- eukaryotic cell (single-celled organism)
- may have a complex life cycle
9
Q
What are the distinguishing features of a fungi?
A
- eukaryotic cell with cell wall
- spreads via spores or rapid division
- some infect external skin and nails, while others enter the host’s body
10
Q
What are the distinguishing features of a macroparasites?
A
- multicellular
- they typically don’t multiply in their final or definitive host, but instead produce transmission stages (eggs and larvae)
11
Q
What is a protist?
A
- a group of eukaryotic, unicellular or colonial organisms that include protozoa such as Amoeba.
12
Q
What is a prion?
A
- prions are infectious agents that only consist of protein
- they have no nucleic acid
- referred to as non-cellular pathogens
13
Q
What is bacteria?
A
- prokaryotic, unicellular organisms
- DNA is contained in a single loop
- some bacteria have an additional circle of genetic material called a plasmid
14
Q
What is the average size of bacteria?
A
1000 nano-meters (10^-9)
15
Q
What is the average size of viruses?
A
Their size ranges from 20 - 40 nano-meters (10^-9)
16
Q
What is the effect of prion diseases also known as transmissible spongiform encephalopathies (TSEs)?
A
- rare progressive neurodegenerative disorders that affect humans and animals.
- symptoms include spongiform changes associated with the loss of neurons (brain damage) and the inability of the body to induce inflammatory response.
- typically progress rapidly and always fatal.
17
Q
What is spongiform?
A
The post-mortem appearance of the brain with large holes that show where cells have been destroyed.
18
Q
What is a virus?
A
- microscopic pathogen
- typically a small piece of genetic material encased in a shell called a capsid.
- considered non-cellular pathogens
- while they are considered to be non-living, viruses have nucleic acid.
19
Q
How do viruses cause disease?
A
- Alone, viruses can do little harm.
- If they enter a living cell, it will begin to replicate and causes disease.
- Because they replicate at an extraordinary rate and they contain nucleic acid means that they can mutate and evolve.
20
Q
What is a plasmid?
A
- small DNA molecule found in cells (often bacterial cells)
- separate from the chromosomal DNA
- plasmid may contain genes that give the bacterium some advantage over other bacteria (eg. resistance to antibiotics)
21
Q
What are microbes?
A
micro-organisms
22
Q
What is the average size of protozoan?
A
- size varies
- most are less that 50 micrometers
23
Q
How does bacteria cause disease?
A
- by secreting toxins (chemical change)
- invading cells (physical change)
- forming bacterial colonies that disrupt normal cell function.
24
Q
How are bacteria classified according to their shape?
A
- spherical (cocci)
- rod (bacilli)
- spiral (spirilla)
- comma (vibrios)
- corkscrew (spirochaetes)
25
What is fungi?
- eukaryotic organisms
| - include yeasts, moulds and crop-destroying rusts and smuts.
26
What are macroparasites?
- macro-organisms that cause disease
- can be direct or indirectly as vectors for disease
- includes roundworms, flatworms and anthropods like ticks, mites, lice and fleas.
27
Explain what a vector is and provide an example.
- an organism that transmits a disease-causing pathogen
- eg: mosquitoes are vectors of the malaria-causing parasitic protozoan
- a vector often carries one part of the life cycle of the pathogen from one organism to the next.
28
What is direct droplet transmission?
- droplet transmission of a pathogen to a new host over distances of one metre or less.
29
What is airborne transmission?
- the transmission of droplets containing pathogens over distances greater than one metre
30
What are fomites?
- inanimate objects that become contaminated by pathogens from an infected individual or reservoir.
31
How does direct transmission occur?
- direct contact with people (through touch, saliva, mucous, etc)
- direct droplet transmission
- pregnant women can transmit infectious diseases (eg. STDs) to unborn children via the placenta, during birth or through breastfeeding.
32
How does indirect transmission occur?
- transmission from fomites
- airborne transmission of droplets
- transmission from environmental reservoirs such as soil and water.
- transmission from contaminated food and drinking water
33
What is an epidemic?
It is an outbreak or unusually high occurrence of a disease in a population or region.
34
What is a pandemic?
It is an outbreak of a disease over a whole country or an a global scale.
35
Which pathogen can be anaerobic or aerobic?
Bacteria
36
What were Koch's postulates?
1: It must be shown that the micro-organism believed to be the cause of the disease is always present in the diseased organism.
2: The micro-organism must be isolated and grown in a pure culture; that is, a culture only containing that macro-organism.
3: Micro-organisms from the pure culture, when injected into a healthy organism without the disease, must produce the disease.
4: Micro-organisms isolated from the experimental organisms, grown in pure culture, and compared with the micro-organisms in the original culture, are shown to be identical.
37
What was the theory of spontaneous generation?
It is an obsolete idea that certain life forms could arise from dust or dead tissue.
Eg. it was believed that mould and maggots would occur spontaneously from non-living matter.
38
What idea did Koch and Pasteur both provide evidence towards?
In the 1850s their research provided evidence that many diseases were caused by micro-organisms.
39
What did Koch show? (ANS are examples)
- Koch showed that bacteria were the cause of the disease called anthrax in horses, sheep, cows and humans.
- He also demonstrated that bacteria caused tuberculosis in humans.
40
Explain Pasteur's experiment process on microbial contamination.
- Pasteur prepared a nutrient broth that was boiled to kill any micro-organism
- that broth was then poured into two swan-neck flasks
- the control flask is left alone, while the other flask's neck is broken off
- microbial growth is observed and compared.
41
How did Pasteur's conclusions change our understanding of the causes and transmission of infectious diseases?
Pasteur's conclusions led to the wide acceptance that diseases are caused by microbes and can be transmitted from one host to another.
42
What did Pasteur's work contribute to the development of?
- vaccinations for fowl cholera, anthrax and rabies
43
What are epithelial surfaces?
They are surfaces that line organs and blood vessels.
| This includes the skin and the lining of gastrointestinal, respiratory and urogenital tracts.
44
What are extracellular pathogens?
Pathogens that grow within the tissues of the body and do not need to be in a host cell for growth.
45
What are extracellular pathogens?
Pathogens that grow within the tissues of the body and do not need to be in a host cell for growth.
46
What are intracellular pathogens?
Pathogens that grow and reproduce inside the cells of a host; all viruses are intracellular pathogens.
47
Explain 'entry into a host' in terms of the pathogens actions.
- some pathogens can cause disease on the surface of the skin.
- most pathogens must enter a host to cause disease.
- microbes enter through protective barriers and can be extracellular and intracellular.
48
What are the protective barriers of plants?
- they include physical barriers: thick cell walls, thick cuticles, and the presence of a secondary cell wall or thick bark.
- chemical barriers include antimicrobial compounds
49
What are protective barriers of humans?
- skin
- mucous membranes
- cilia in the respiratory tract
- surfaces of the body covered by microbes (normal body flora)
- chemical barriers found in body fluids and secretions, and the pH of fluids
- other bodily secretions such as oil glands and fatty acids
50
How does skin function against pathogen entry?
- mechanical barrier: unbroken skin protects other tissues, and collects and holds pathogens
- if the skin is cut, the blood produces a blood clot that seals the wound and prevents pathogens from entering
51
How do the surfaces of the body covered by microbes (normal body flora) function against pathogen entry?
- these microbes act as a physical barrier; they also reduce the area available for pathogens to attach and become established.
52
How do mucous membranes function against pathogen entry?
- they occur along the alimentary canal, respiratory surfaces and urogenital surfaces (eg. bladder)
- the mucous traps pathogens
53
How do cilia in the respiratory tract function against pathogen entry?
- cilia beat in one direction to sweep mucous containing pathogens and small particles out of the lungs; coughing helps to remove materials and pathogens from the lungs.
54
How do chemical barriers function against pathogen entry?
- found in body fluids and secretions, and the pH of fluids
- low pH on the skin discourages growth of microbes
- stomach juices are highly acidic and in this acidity, along with peristaltic washing and the thick mucous lining, make it difficult for microbes to colonise the stomach
55
How do other bodily secretions such as oil from oil glands and fatty acids function against pathogen entry?
- inhibit the growth of some bacteria and fungi
| - some secretions contain antibacterial factors
56
What are cytotoxins?
- substances that are toxic and destructive to cells
57
What are the adaptations of viruses (intracellular pathogen) to facilitate entry into host cells and to change the biology of the host cell?
- after attaching to the host cell, the virus must enter to release its nucleic acid from the protective coat or lipid envelope
- viruses enter cells by either fusing with the membrane of the host cell or by forming a pore in the cell membrane of the host cell to deliver the genetic material into the cytoplasm.
58
What are the adaptations of bacteria (intracellular pathogen) to facilitate entry into host cells and to change the biology of the host cell?
- some enter host cells by phagocytosis (a function of macrophages)
- some have adapted to survive and replicate inside macrophages
- some invade cells by using adhesions, which bind them to deeper tissues (eg. alveoli)
- bacterial toxins aid invasion by breaking down specific host proteins and disrupting signalling pathways.
59
What are the adaptations of protozoans (intracellular pathogen) to facilitate entry into host cells and to change the biology of the host cell?
- intracellular parasites are much larger than bacteria, so they must expend energy to invade cells through a variety of complex pathways.
- as it moves through the cell, the protozoan secretes lipids that form a vacuole compartment in which the protozoan is protected
- from its compartment the protozoan takes up its nutrients from the host cell
60
What are the adaptations of fungi (intracellular pathogen) to facilitate entry into host cells and to change the biology of the host cell?
- some fungi enter host cells
| - meningitis can be formed by a fungi which uses white blood cells to reach the host's brain cells
61
Give an example of a disease that is directly transmissible.
Ebola Virus - transmitted though direct contact with bodily fluids of infected animals or humans.
62
Give an example of a disease that is in-directly transmissible.
Cholera - caused by bacterium and is transmitted through contaminated water
63
Give an example of a disease that is transmitted through a vector.
Malaria - is caused by a protozoan, spread through a mosquito.
64
What is a natural or innate immune response?
General, non-specific defense and response mechanisms, primed and ready to fight an infection at all times.
65
What kind of defence do plants and animals rely on for infections?
- innate immune responses and preformed defences.
(no adaptive immune system to infections)
pg. 137 and 150 contradict each other
- this needs confirmation!! if you see this Kha tu pls message me
66
What is a preformed defence?
- meaning 'made beforehand'
- they are defence mechanisms that are primed and are 'ready to go', as compared to the responses that are induced by the exposure to a pathogen/
67
Passive, preformed defence mechanisms in plants include:
- physical and chemical responses
68
What are chemical barriers in plants?
(general: stored chemical compounds that protect the plant and/or are released upon infection by a pathogen, including: plant defensins and pH)
- secretory cells, glands and ducts which secrete defensive compounds
- phenolic compounds are secreted by some plants to discourage herbivores and inhibit some plant microorganisms
69
What are physical barriers in plants?
- properties of the plant surface including: waxy leaf cuticles and thickened, tough cell walls
- the presence of secondary cell walls
70
What are defensins?
antimicrobial or anti-fungal plant peptides
71
Defence response of an Australian plant to a named pathogen
139
72
what is the active response of a plant?
139
73
What is an inflammatory response?
inflammation of the tissue in response to an infection; designed to isolate and destroy the foreign particles, it also prepares the the tissue for healing.
74
What are lysosomes?
membrane-bound cell organelles containing enzymes which break down extracellular and intracellular materials, pathogens engulfed by macrophages, virus particles and bacteria; lysosomes also play a role in the processing and secretion of inflammation signals.
75
What is phagocytosis?
The active process in which phagocytic cells enclose a pathogen and digest it in their interior
76
What are macrophages?
White blood cells found in tissues and in especially large numbers in the gastrointestinal tract, lungs, liver and sleep; long-lived cells that circulate the blood.
77
What are phagocytes?
White blood cells that engulf and destroy microbes.
78
What are cytokines?
Small proteins secreted by a broad range of cells, they are signalling molecules that help cell to cell communication in infection, immune responses and inflammation response.
79
What are histamines?
A chemical compound released by special types of white blood cells (called mast and basophil cells) in response to an injury of infection by pathogens; histamines regulate both the innate and adaptive responses
80
What are neutrophils?
They are short lived, white blood cells that are abundant in blood but not in normal healthy tissue.
81
How are responses to infection initiated?
To mobilise a response the immune system must be able to distinguish self from non-self.
Non-self includes foreign particles and pathogens
82
What is the difference between 'responses to infection' and 'symptoms of disease'?
Responses to infection: the host's reaction to the invading pathogen, such as the inflammation response.
Symptoms of disease: the signs of possible infection (eg. black spots in plants or diarrhoea in humans)
83
What are chemical changes that occur in the presence of pathogens?
- specific white blood cells (phagocytes called macrophages) produce a number chemicals (eg. cytokines)
- other white blood cells produce histamine
- different types of cells of the immune system move into the site of inflammation, along with a large supply of proteins to fuel the immune response.
84
What are physical changes that occur in the presence of pathogens?
- the cytokines and histamines produced cause physical changes to cells and tissues such as dilation of blood vessels around the site of infection to allow increased blood circulation
- there is a change in the permeability of blood vessels and development of gaps in the cell membranes surrounding the infected areas to allow the larger immune cells of the blood to pass out of the bloodstream into the infected tissue.
- tissues swell due to the increased amount of blood and proteins.
- tissues become red and warmer and can be painful due to the expansion of tissues putting pressure on the nerve cells.
85
What features of the immune systems of plants and animals are shared?
- both have innate immune systems
| - both attack pathogens with bursts of superoxide, hydrogen peroxide, nitric oxide and toxic antimicrobial peptides.
86
How does the immune system of plants and animals differ?
- animals have mobile immune cells
- animals have a circulatory immune system
- responses to pathogens can be exerted throughout the whole body. Plant cells are largely responsible for its own defence
87
Physical changes that occur in animals in the presence of pathogens?
- increase in the diameter of blood vessels
- increase in permeability of blood vessels
- increase in temperature of the tissues and body temperature
- development of blood clots
88
Chemical changes that occur in animals in the presence of pathogens?
- toxic hydrogen peroxide, superoxide and nitric oxide produced by phagocytes help kill the pathogen
- production of cytokines (that set up the inflammatory response)
- secretion of adhesions during the inflammation response
- secretion of chemicals that bring about blood clotting.
89
What are the key roles of the inflammatory response in fighting infections?
(humans)
- to bring plasma proteins and phagocytes to the site of infection to help kill the pathogen
- to provide a physical barrier to prevent further spread of the infection and make the host aware of the infection
- to promote the repair of damaged tissue
90
What is an example of the immune response in plants?
- Rapid deposition of lignin following infection reinforces the cell walls of the host and increases resistance to pathogens.
- Lignin can also bind to hyphal tips and bacteria, stopping them from entering the host and restricting the diffusion of their enzymes and toxins into the cell wall.
91
What are the defences and responses of Eucalyptus to P.cinnamoni?
Preformed defences:
- Physical barriers: thick cuticle, thick bark, waxy leaves
- Chemical barriers: stored oils
Active or induced response:
- the development of periderm that separates damaged tissue from healthy tissue
- secretion of protective gums
92
What is the periderm?
a corky protective tissue that develops beneath the surface of damaged or infected tissue
93
What is a hypersensitive response?
- part of the active response to infection
- it is an immune response in plants to stop the spread of a pathogen by activating rapid cell death of the plant's cells in the area of infection.
94
What are active responses of plants against the entry of a pathogen?
- the reinforcement of the cell wall and/or secondary cell wall
- hypersensitive response
- development of an abscission layer to separate
95
How does the human immune system respond to non-self?
- innate immune system - fast acting, non-specific and broadly effective general defence
- specific adaptive immune system - specialised
96
How does the human immune system respond to non-self?
- innate immune system - fast acting, non-specific and broadly effective general defence
- specific adaptive immune system - specialised
97
What does the specific, adaptive immune system include?
- Humoral defence involving B cells, plasma cells and antibodies
- Cell-mediated defence involving T cells
98
What does the non-specific, innate immune system include?
- protective barriers on the outside of the skin
- protective barriers on membranes 'inside' the body
- bacteria killing substances
- scavenger cells - phagocytes
- complement system
- natural killer cells
99
What does the non-specific, innate immune system include in humans?
- protective barriers on the outside of the skin, epithelial surfaces
- protective barriers on membranes 'inside' the body
- bacteria killing substances
- scavenger cells - phagocytes
- complement system
- natural killer cells
100
What is the complement system?
A system of soluble proteins that activate one and other in a chain reaction to support (complement) defence mechanisms.
101
What are natural killer (NK) cells?
Cells that specialise in identifying cells that are infected by a virus or have become cancerous by looking for changes in cell surfaces.
102
What does the innate immune system consist of in the human body?
- the skin and all mucous (epithelial surfaces), which form external and internal barriers
- defence cells formed from white blood cells (leukocytes) such as phagocytes
- various substances circulating in the blood and in body fluids, such as cytokines and antimicrobial peptides (defensins)
- complement system
- natural killer
103
What are interleukins?
Cytokines that can alter the behaviour of cells; produced by white blood cells
104
What are interferons?
Produced by cells infected with viruses to inhibit viral replication and activate natural killer cells and cytotoxic T lymphocytes
105
What are antigens?
Any substance, microbe or pathogen that is usually foreign to an organism's own body and thus triggers an immune response
106
What is an antibody?
Antibodies are specialized, Y-shaped proteins that bind like a lock-and-key to the body's foreign invaders — whether they are viruses, bacteria, fungi or parasites.
107
What is an antibody?
Antibodies are proteins produced by the body in response to the presence of a specific antigen. By joining with the antigens and clumping them together the antigens can be more easily destroyed by macrophages. Some antibodies can neutralise toxins produced by antigens.
108
In what ways does an antibody work?
- neutralising the pathogen by either attaching directly to the surface through the antigen - antigen complex or by attaching to the toxins produced by bacteria
- activating other defence cells (eg. phagocytes in the tissue and mast cells)
- activating the complement system
109
What are some examples of specialised T cells?
- helper T cells
- regulatory T cells
- killer T cells (cytotoxic T cells)
- memory T cells
110
What are the functions of helper T cells?
- release certain messenger substances called lymphokines
| - stimulate the production of antibodies by B cells and their dispersal through the bloodstream
111
What are some examples of specialised T cells?
- helper T cells
- regulatory T cells (suppressor T cells)
- killer T cells (cytotoxic T cells)
- memory T cells
112
What are the functions of regulatory T cells?
- slow down the workings of the body's defence so that the immune system
113
What are the functions of regulatory T cells (also known as suppressor T cells)?
- slow down the workings of the body's defence so that the immune system 'calms down again' after the infectious agent has been destroying
- the regulatory T cells have the receptor molecule on their surface and can function together with killer T cells (known at T8 cells)
114
What are the functions of killer T cells (cytotoxic T cells)?
- can directly destroy bacteria or cells that have become infected by a virus or have become cancerous
- identify pathogens only when they are 'presented' with the help of other defence cells in the body
- when activated they release a substance that gets into the wall of the bacterium or infected cell, together with the pathogen, dying from the loss of fluids and electrolytes
115
What are the functions of memory T cells?
- remember information about the pathogen and have the ability to recognise the original invading antigen for a longer time
- they can also pass on this information immediately if their is another infection, resulting in a quick response
116
What are lymphokines?
- subset of cytokines
| - protein molecules that signal between cells to stimulate an adaptive immune response
117
Where are white blood cells produced?
Bone marrow
118
What is a localised response?
If a pathogen passes the protective barriers and begins to replicate phagocytes will immediately target the infection.
119
What are the purpose of neutrophils in fighting off an infection?
Macrophages are the first phagocytes to encounter pathogens in the tissues but are then reinforced by neutrophils. After undergoing phagocytosis they die.
120
What are the purpose of cell-surface receptors on macrophages and neutrophils?
They distinguish self from non-self.
121
How do phagocytes target pathogens?
- they move by amoeboid action
- they send out a protrusion that allows them to surround the invading pathogen(s) and engulf them.
- phagocytes release digestive enzymes which break down the trapped pathogen(s).
122
Where to B cells originate from?
- they start as an unspecialised stem cells.
- the stem cells differentiate into lymphocytes.
- the lymphocytes that continue their development in the bone marrow are called B cells
(B - bone marrow)
123
Where do T cells originate from?
- they start as an unspecialised stem cells.
- the stem cells differentiate into lymphocytes.
- in an immature state they migrate from the bone marrow and continue their development in the thymus.
(T - thymus)
124
Where do all blood cells originate from?
- from the bone marrow
- all start as stem cells
- they differentiate into white blood cells, red blood cells and platelets
125
How is the role of white blood cells important for the human immune system?
- they are a critical role
- white blood cells differentiate into lymphocytes and phagocytes
- lymphocytes are receptors for antigens.
- B and T cells are the two types of lymphocytes responsible for the adaptive immune system
- white blood cells can also produce chemicals called antitoxins which can destroy the toxins bacteria produce when they invade the body.
126
Where do B cells accumulate and circulate?
- they accumulate in the spleen and lymph nodes
| - they circulate in the blood and lymphatic systems
127
Where do B and T cells accumulate and circulate?
- they accumulate in the spleen and lymph nodes
| - they circulate in the blood and lymphatic systems
128
What do plasma cells do?
Plasma cells make large amounts of specialised antibody and release them into the body.
129
What does the adaptive immune consist of?
- made of antibodies (as soluble proteins in the blood)
- B cells
- T cells
130
What is the meaning of cell-mediated?
- concerning T cells rather than antibodies
131
How do T cells differ in their function to B cells?
- they do not generate antibudy-producing plasma cells
| - they are lymphocytes that destroy antigens directly
132
What is the meaning of proliferate?
To increase rapidly in number
133
What is innate immunity?
immunity that is naturally present rather than due to prior exposure to an antigen
134
What is acquired immunity?
immunity though exposure to a specific antigen (eg. through an infection or vaccination) It can be active or passive and natural or artificial.
135
What is a vaccination?
The ingesting or injection into the body of antigens from living, dead, weakened or non-virulent strains of the micro-organisms.
136
What is the humoral immune response?
- involves B cells that recognise antigens and pathogens.
- used against extracellular infections ie. antibodies are made available for a pathogen outside the cells in the blood and in body fluids
137
What is the cell-mediated immune response?
- mostly involves T cells and does not involve antibodies
| - it involves the activation of T cells and the release of various cytokines in response to an antigen
138
hat are the steps involved in a cell-mediated immune response?
- antigens bind to T cells
- interleukins activate T cell function
- T cells proliferate, producing cytotoxic T cells which destroy the antigens
139
What are the steps involved in a cell-mediated immune response?
- antigens bind to T cells
- interleukins activate T cell function
- T cells proliferate, producing cytotoxic T cells which destroy the antigens
140
What are the steps involved in a humoral immune response?
- the antigen binds to B cells
- interleukins or helper T cells activate B cells
- B cells proliferate and produce plasma cells, which make antibodies
- antibodies are released and circulate through the body to antigens
- B cells produce memory cells
141
What are antivirals?
- manufactured drugs that either inhibit a virus's ability to replicate or strengthen the host body's immune response to the viral infection
142
What is quarantine?
- derived from the Italian word quarantina meaning 'forty days'
- refers to a range of measures that aim to control the spread of the disease (eg. isolation)
143
What is the definition of immunity?
The state of protection that occurs when a person has been vaccinated or has had an infection and recovered
144
What are fomites?
Objects or materials that carry infection
145
What is the meaning of chronic?
A wide group of conditions, illnesses and diseases, generally characterised by their long-lasting and persistent effects as distinguished from long-term, intense acute conditions
146
What is herd immunity?
When a significant proportion of individuals within a population are protected against a disease through immunisation
147
What is a vaccine?
a substance that is introduced into the body to stimulate the body's acquired
148
How can the spread of infectious diseases be controlled?
- prevention
- treatment
- control
149
What does the prevention of infectious diseases refer to?
Refers to a range of interrelated measures which reduce the risks of, and ultimately stop, infections by pathogens in the first place.
150
What is an example of the prevention of infectious disease?
- vaccination
- good hygiene practices
- health campaigns
- genetic engineering
151
What does the treatment of infectious diseases refer to?
Defends on a range of factors, including the type of pathogen, its virulence, the incubation period, the severity of the disease and the treatment drugs available.
152
What is an example of the treatment of infectious disease?
- antibiotics
| - antivirals
153
What does the control of infectious diseases refer to?
Refers to the procedures employed to contain and stop the spread of disease.
154
What is an example of the control of infectious disease?
- surveillance and early detection
- quarantine methods
- vector control
155
What factors are important to be understood in limiting the spread of an infectious disease?
- the main mode of transmission
- how the pathogen reproduces or replicates
- the type of setting where spread is most likely to occur
- individual and population susceptibility to the disease
- transmission at different stages of infection
- seasonality of infection
156
What are some factors limiting the spread at the local level?
- personal hygiene
157
What are some factors limiting the spread at the local level?
- personal hygiene
| - public health responses
158
What are some factors limiting the spread at the regional level?
- surveillance
| - area quarantining
159
What are some factors limiting the spread at the global level?
- global surveillance
- trade restrictions
- travel warnings
160
How do hygiene practices reduce the spread of disease?
hygiene practices can reduce the risk of objects, materials or food from being contaminated and infectious disease being contracted
161
How does the procedure, quarantine, prevent the spread of disease?
quarantine rules limit or control human mobility through travel restrictions and impede the introduction of disease through surveillance, border security and screening.
162
How is the procedure, public health campaigns, used to prevent the spread of disease?
public health campaigns include health promotion information, immunisation campaigns and disease prevention programs.
163
How does the procedure of using pesticides prevent the spread of disease?
Pesticides can prevent and control disease vectors, such as mosquitoes, and control insect infestations and plant diseases in agriculture.
resistance of insects to pesticides is now one of the greatest problems impacting on the global control of vector-borne diseases.
164
How is the procedure, genetic engineering, prevent the spread of disease?
it makes it possible to engineer the genes of vectors such as mosquitoes in order to control the spread of diseases such as malaria, dengue and Zika virus.
165
How can passive immunity be provided?
It can be provided when a person is given antibiotics. Can occur through: Mother to child through the placenta, breast feeding or antibody serum injection
166
What are the subsections of adaptive immunity?
```
Naturally acquired immunity:
- passive: antibodies received naturally
- active: result of exposure to a pathogen
Artificially acquired immunity:
- active: vaccinations
```
167
Are vaccinations effective?
They are effective in stopping infections, which reduces the need for antibiotics and therefore helps limit the spread of antibiotic resistance.
168
What are the two major ingredients in vaccinations?
- antigens
| - adjuvants
169
How do adjuvants function in vaccinations?
Adjuvants amplify immune responses by targeting the defence cells and chemicals of the innate defence system
170
How do adjuvants function in vaccinations?
Adjuvants amplify immune responses by targeting the defence cells and chemicals of the innate defence system
171
How do antigens function in vaccinations?
antigens cause the immune system to produce antibodies and/or T cells against a specific pathogen or its toxin.
172
What is morbidity?
the rate of disease in a population
173
What is mortality?
the number of deaths in a population
174
What are antibiotics?
manufactured drugs that either kill bacteria or stop them from growing so that the immune system can more easily destroy them
175
What are pharmaceuticals?
manufactured compounds used as medicinal drugs
176
What do antivirals target?
- they treat a narrow range of viruses
| - includes treatment of influenza, HIV, herpes, hepatitis B and C
177
What do antibiotics target?
- they target bacterial pathogens
| - do not work against viral infections like the cold or influenza
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What is the first priority of when a disease occurs?
- must be identified, contained and controlled at its source as quickly as possible.
179
What is the incidence rate?
it is the number of new cases of a disease at a given time
180
What is the prevalence?
the number or proportion of cases of a disease at a given time
181
What is malaria caused by?
it is a disease caused by protozoa
182
Identify two chemical responses to pathogens in humans:
- Histamine- increases permeability of blood vessel walls
| - Pyrogens- causing fever, stops viruses from replicating
183
What is a pyrogen?
Pyrogens are substances that induce fever. They act on the hypothalamic thermoregulatory centre. They inhibit the heat-sensing neurons while stimulating the cold-sensing neurons, thus, resulting in the hypothalamus increasing body temperature above the normal range.
