bio 8C Flashcards
controlling pathogen spread
explain the method of identifying pathogens: physical
- Visualising pathogens using microscopes to determine their structure
explain the method of identifying pathogens: phenotypic
- Selective media (agar plates)
- Allows certain pathogens to grow and multiply to test for their presence in a sample
- Biochemical test panels
- Series of tests designed to specify a sample’s genus and species
- e.g. run a gram stain to determine if bacteria are gram-positive or negative THEN test if they are aerobic or anaerobic
- Series of tests designed to specify a sample’s genus and species
explain the method of identifying pathogens: immunological
- serology
- The diagnosis of disease based on the presence of antibodies or antigens in a person’s serum (fluid + solute component of the blood (no blood cells, platelets, and clotting factors))
○ e.g. detect the presence of pathogenic antigens through enzyme-linked immunosorbent assay (ELISA)
* Method
- Antibodies specific to a certain pathogen are attached to a plate
- The sample to be tested is applied to the place (causes pathogen antigens present to attach to antibodies)
- Second detection antibody (linked to colour-changing enzyme) is added, binding to any antibody-antigen complexes present
- Substrate is added and reacts with the enzyme on the second antibody and changing colour/emitting a signal to reveal if any pathogenic antigens are present
- The diagnosis of disease based on the presence of antibodies or antigens in a person’s serum (fluid + solute component of the blood (no blood cells, platelets, and clotting factors))
explain the method of identifying pathogens: molecular
- Hybridisation-based detection
- Labelled segments of genetic material that are complementary to a pathogen’s genetic material are added to a sample
- If a signal is generated, it means a pathogen is present
- Whole-genome sequencing
- Provides detailed information about the pathogen
- Labelled segments of genetic material that are complementary to a pathogen’s genetic material are added to a sample
explain the mode of pathogen transportation: droplet transmission
Respiratory droplets containing pathogens can remain suspended in the air for a short period of time before falling to a surface
explain the mode of pathogen transportation: airborne transmission
- Pathogens spread via small particles that stay in the air for prolonged periods of time after a person sneezes, coughs, exhales, or talks
explain the mode of pathogen transportation: direct physical contact
- Pathogens can be spread when a host physically touches another individuals
- Skin-to-skin touch
- Sharing of bodily fluids
- Oral contact
- Contact with contaminated material during medical procedures
explain the mode of pathogen transportation: indirect physical contact
- No direct host-to-host contact - spread via fomites
- Food
- Water
- Tissues
- Needles
- Vectors (mosquitoes)
explain the mode of pathogen transportation: faecal-oral transmission
- Pathogens excreted in faeces can end up being consumed by another person indirectly via contamination of food or water by infected faeces
- Can also occur via airborne or droplet routes through the aerosolization of pathogens when faeces is flushed
explain the strategy of controlling disease transmission: prevention
- Improving hygiene and sanitation via handwashing
- Sterilising hands and surfaces/tools using antiseptics and disinfectants
- Ensuring access to clean water and food
- Using personal protective equipment (PPE) such as gloves and masks when dealing with sick people
- Vaccination, if a vaccine exists for the disease in question
- Lockdown of areas/restrictions to reduce people’s movement and the chance of spreading a disease
explain the strategy of controlling disease transmission: screening
- Routine testing for the presence of disease in a population
- Allows public health workers to quickly see who in a population is affected so they can target their response
- Officials observe medication sales at pharmacies + look for changes that might indicate that the prevalence of certain symptoms or illnesses has increased
explain the strategy of controlling disease transmission: quarantine and isolation
- Once a person becomes ill or has the potential to become ill (e.g. is returning home from visiting an affected area overseas), they may be separated from healthy people to ensure they don’t spread their disease to the community
explain the strategy of controlling disease transmission: identification of the pathogen
- Scientists will attempt to identify which pathogen is present in an individual so they can initiate the appropriate responses
explain the strategy of controlling disease transmission: identify and control mode/s of transmission
- Once officials know which pathogen is present, they can take appropriate steps to mitigate its transmission
- e.g. if a respiratory pathogen is threatening to cause an outbreak, measures that reduce the risk of airborne and droplet transmission (e.g. wearing of surgical masks, social distancing) will be taken to control transmission
explain the strategy of controlling disease transmission: treating infected individuals
- Using medication (antibiotics, antivirals, fungicides) to target pathogens
- Antibiotics
○ Treat diseases caused by bacteria
§ Selectively affect bacterial cells by targeting specific biochemical pathways or components unique to bacteria (does not damage self-cells) - Antivirals
○ Treat diseases caused by viruses
§ Designed to target viruses by interfering with their ability to attach to, replicate in, and exit from a host cell - Fungicides
○ Treat diseases caused by fungi
§ Specifically targets fungal cells
- Antibiotics
