Disease challenges and strategies Flashcards
(26 cards)
Emerging Pathogens
A previously unknown or new pathogen that has spread to new populations/locations
Eg: influenza, avian influenza and COVID-19
Re-emerging Pathogens
Pathogens that have caused disease in the past and are now reappearing into a population without immunity and increases to an epidemic proportion
Eg: measles, tuberculosis, malaria, gonorrhoea
Sporadic
If they are only seen infrequently and in small numbers of people
Eg. the occasional cases of rabies
Endemic
If they are consistently found in certain regions
Eg. malaria which is endemic to tropical regions
Epidemic
Rapid spread of the disease across a number of countries and a large number of people are affected
Eg. the Ebola outbreak in 2018 which spread across the Democratic Republic of Congo and Uganda
Pandemic
If pathogens become worldwide threats to health, huge financial burden, high mortality rate
Eg. COVID-19 pandemic starting in late 2019
European arrival on Aboriginal and Torres Strait Islander peoples
British colonisation in Australia led to the dramatic decline in populations of Australian Aboriginal peoples and Torres Strait Islander peoples due to introduction of new diseases that the population had no prior exposure to.
This included: smallpox, chickenpox syphilis, tuberculosis, influenza and measles.
These diseases devastated Aboriginal and Torres Strait Islander peoples resulting in significant fatalities.
The arrival of Europeans had an almost immediate impact.
- Land clearing for crops
- Fencing of livestock
- Water management
- Forestry for wood
- Introduction of weed species
- Hunting of native wildlife.
→ This resulted in many Aboriginal people becoming malnourished or dying of starvation.
→ After being dispossessed of their land, Aboriginal people started living much closer together in communities and this only exacerbated the spread of diseases
Physical methods
identifying pathogens based on shape and size
- X-ray crystallography- determines the structure of many viruses
- Electron microscopy - helps distinguish various kinds of viruses
Immunological methods
Detect specific viral antigens or antibodies
- Sandwich ELIZA
Antibody put at bottom of well, human serum added (with antigen), antibody with enzyme added to see if the person has the pathogen through a colour change
Genotypic and molecular methods
Methods of identifying bacteria by examining its genetic material
Phenotypically
Grow things on agar plate and add stains
Gram staining
Sterilisation
The removal or killing of the microbes from surfaces. Done by heat (methods as autoclaving) → Very effective method and relies on pressurised steam at a high temperature.
Chemical agents
Antiseptics and disinfectants
Disinfectants inhibit or kill pathogenic organisms on non-living surfaces, such as taps and door handles.
Antiseptics are used for inhibiting the growth of pathogens on living surfaces such as the skin.
Antibiotics
Class of antimicrobial drug used in the treatment and prevention of bacterial infections
Antivirals
A type of medication that is used specifically for treating viral infections.
Social strategies to control spread
Restrict movement of people
- Lockdown, work from home, quarantine for returned travellers, quarantine for conant of infected individual, travel restriction, limiting visitors at home
Prevent spread from person to person
- Social distancing, masks
Reduce chances of infection
- Public education about personal hygiene, vaccination programs
Manage illness when injected
- GPs, hospital care
How authorities can assess risk
- Testing, contact tracing, wastewater testing
Modes of transmission
- Direct transmission- such as by person to person contact→ kissing, sexual contact (eg. chickenpox, chlamydia)
- Indirect transmission:
By airborne droplets or particles (sneeze or cough)
By contact with contaminated objects (medical instruments)
By ingestion of contaminated food or water
By biological vehicles (contaminated blood or faeces)
By vectors (ticks, mites, fleas or mosquitoes)
R0
The R0 value (the basic reproduction value) is the average number of people an individual with a disease will infect.
D = duration of infection, B = how many individuals are infected by an infectious person per day
R0 = D x B
Vaccination programs
Aim of vaccination programs is to reduce the impact of vaccine-preventable infectious diseases through achieving high rates of immunisation in the community.
Herd immunity
Is the indirect protection of unvaccinated members of the population due to the vaccination of the majority of the population
Immunotherapy
Immunotherapy is a type of treatment that alters the immune response in an individual to combat diseases such as cancer and autoimmune diseases. One treatment used is monoclonal antibodies
Monoclonal antibodies
Class of drugs that are specifically designed antibodies used in the treatment of some diseases: cancer and autoimmune disease (cloned antibodies)
They are artificially produced antibodies that bind to one specific type of antigen
Produced in the laboratory by stimulating the production of B lymphocytes in mice injected with a specific type of antigen
How to make Monoclonal antibodies
- A lab mouse is injected with antigen X which activates the production of B cells, producing antibodies against antigen X.
- Stimulate artificial active immunity in mouse - plasma cells are produced against antigen X
- These cells are fused with a tumour inducing cell and become a hybridoma cell (continue cloning and creating the antigen).
*conjugated add chemotherapy drug to monoclonal antibody - will help deliver chemotherapy
Monoclonal antibodies for autoimmune diseases
- Monoclonal antibodies can be designed to act against specific cells of the immune system which cause autoimmune disease.
- There are currently no reliable and safe strategies to cure autoimmune diseases. Severe cases require cytotoxic drugs, which frequently cause serious side effects.
