chapter 6: disease challenge and strategies Flashcards
difference between emerging and re-emerging pathogens
- examples of each
emerging (new)
- a disease caused by a newly identified or previously unknown agent
- e.g. covid-19
re-emerging (coming back)
- a disease which reappears after a significant decline in its incidence
- re-emerging diseases were once controlled but have increased to a level that causes significant health issues
- e.g. monkey pox
define infectious disease
infectious diseases are transmitted from person to person through the transfer of a pathogen such as bacteria, viruses, fungi or parasites
difference between an epidemic and a pandemic
epidemic:
- widespread infectious disease in an area at a particular time
- a concern is that the disease may spread more widely and become a pandemic
pandemic:
- global outbreak of a disease
- it affects a high proportion of the population
- uncontrolled spread of the pathogen occurs across a wide geographic area
- community level outbreaks in at least two WHO regions
state the impact of European (infectious disease) arrival on Indigenous populations
European arrival caused epidemics for Aboriginal and Torres Strait Islander peoples
- prior to European arrival there was little interaction between Indigenous peoples and Europeans
- after settlement, they brought various new diseases and pathogens to populations that had no prior exposure
- through this, it places a burden on their overall health and population –> decreases their population
explain why diseases introduced by Europeans had such a large impact on Indigenous Australians
western diseases were unknown in the Indigenous population
- Indigenous populations had no immunity against them
- large numbers of susceptible individuals –> results in low herd immunity
- rapid spread of new infectious diseases and significant fatalities
describe physical methods to identify pathogens
physical methods can assist in identifying viruses based on size and shape
x-ray crystallography
- which has determined the structure of many viruses
electron microscopy
- which had given us images that distinguish various kinds of viruses
describe immunological methods to identify pathogens
immunological methods detect specific viral antigens of antibodies which allowed for the diagnosis of diseases
ELISA
- a plate has antibodies attached on the test line
- conjugated antibodies are free to move
- when the conjugated antibodies bind to their specific antigen and the attached antibodies, a colour is observed —> indicted a positive test
describe how pathogens can be transmitted between individuals
- airborne
- respiratory (droplets)
- food and water
- sexually
- animal and insect
- health care
describe control measures to prevent or limit the spread of infectious disease
- prevention – clean water, wash hands, safe sex, etc.
- vaccination – reduce the number of hosts
- medication – treat people to reduce transmission
- surveillance – monitor outbreaks to act
- modification of environment – drain ponds, mosquito nets
- improving infection control standards – sterilisation of surfaces/objects, masks, quarantine, etc.
explain why identifying the host or reservoir is important in controlling the spread
- they can also be used to help identify the correct treatment to be given to an infected
- help enable preventative measures
describe 3 ways that antibiotics work
- inhibition of cell wall synthesis –> stops cell wall from being produced
- inhibition of protein synthesis –> stops bacteria from making proteins
- cause injury to the plasma membrane
describe 3 ways that antivirals work
antivirals only act on viruses actively replicating
- block entry of the virus into host cells
- block fusion of virus with host cells
- block uncoating
- prevent replication of the viral genome
- prevent releases of new viruses
- stimulate host immune system
- stops the virus from replicating
why are antibiotics not effective in treating viral infections
viral infections happen inside of the cell, so antibodies won’t be able to get rid of the cell but rather inactivate it.
- it is also not effective because antibodies can’t reach the inside of the cell, just the outside.
what is in a vaccine
vaccines are substances that cause an immune response (active, artificial immunity)
- vaccines work because your immune system makes antibodies and memory cells (specific to the pathogen injected with)
they can be pathogens that are:
- live attenuated
- inactivate
- toxoin of bacteria
- subunits of bacteria or viruses
explain how vaccines provide long-term immunity
- memory cells remember the pathogen that has entered your body
- if a pathogen enters the body, the body would already have an immune response against it because of the memory cells
explain why booster shots are needed for some vaccines
to remind the body’s immune system about the virus it needs to defend it against
explain why diseases such as influenza need new vaccines each year
since there are mutations and the disease itself can evolve, new vaccines are needed to counterattack the new mutation of the disease
define herd immunity
a form of indirect protection of population that applies only to contagious diseases
- reduces the likelihood of infection for individuals who lack immunity
- protection is created by the presence of immune individuals
state two reasons that prevent some people from being vaccinated
- there is no medical team that can assist with getting people vaccinated (no experience with giving vaccines)
- there is not enough money to supply a place with vaccines
- under the age limit in which it is safe to be vaccinated
- immuncompromised people, elderly, pregnant people
explain how herd immunity protects the unvaccinated
protection is created by the presence of immune individuals in the population hence protection is received by unvaccinated individuals
describe monoclonal antibody
clones of antibodies that are made in a laboratory
- they are antibodies desgined to target one specific antigen
- made to help your immune system
describe how monoclonal antibodies are made
produced by cell lines or clones obtained from animals that have been immunised with the substance
- a mouse is injected with antigen X
- this activates the production of its B cells, which produce antibodies against antigen X
- to increase the concentration of these antibodies, repeat injections followed by a booster may be given
- the spleen of the mouse is removed, placed in a culture medium and its cells after separated
- mouse tumour cells that can constantly divide are added to the separated B cells. some B cells fuse with tumour cells to form new cells called hybridomas
- this produces monoclonal antibody which required antibodies against the antigen can be harvested
describe 3 ways in which monoclonal antibodies can act to treat cancer
1. stopping the growth of new blood vessels to cancers
- MAB (avastin) binds to the growth hormones released by the cancer cell, stopping the growth of new vessels
2. signalling immune cells to attack cancer
- some MABs bind to antigens on cancer cells
- act as markers that attract immune cells to attack the cancer cells
3. blocking signals for cell divisions
- MAB (herceptin) binds to these receptors, blocking them from receiving signals growth factors
- this results in slow growth or no growth
describe what an autoimmune disease is
when a person’s immune system attacks their own body
explain how monoclonal antibodies can be used to treat autoimmune disease
MABs aim to reduce the immune response
- attach to cytokines to prevent cell signalling and activation
- attach to T cells, stopping them from getting into the brain/spinal cord and attacking the myelin sheath
- bind to IgE to prevent allergies
- might be possible to stop autoimmunity by using MABs to block certain MHC-II antigens
what is cancer
uncontrolled growth to mutations in the DNA —> uncontrolled cell division
