Preventing and treating disease Flashcards
(23 cards)
What are the 2 types of immunity?
- active
- passive
What is active immunity?
Immunity developed when immune system makes its own antibodies after exposure to pathogen’s antigens
Describe active immunity?
It takes a while to become immune to disease but provides long-term protection because memory cells are produced
What is passive immunity?
Immunity developed when an individual is given antibodies made by a different organism (individual’s immune system doesn’t make antibodies)
Describe passive immunity?
Provides immediate immunity to disease but short-term protection due to no memory cells being produced
What are vaccines?
Introduce pathogen’s antigens into body via injection which stimulates body to produce immune response to pathogen
What may vaccines contain?
- dead or inactivated pathogens
- attenuated (weakened) pathogen strains
- harmless version of toxin
- isolated antigen from pathogen
- genetically engineered antigen
Outline the main stages of vaccination?
1) vaccine containing antigen injected into blood
2) stimulates primary immune response producing antibodies against pathogen
3) memory cells capable of recognising antigens produced
4) on 2nd exposure to pathogen memory cells rapidly divide into plasma cells
5) plasma cells rapidly produce antibodies against the pathogen
6) pathogen destroyed before symptoms experienced
What factors affect successfulness of a vaccine?
Availability = vaccines must be affordable and available in large amounts for mass immunisation
Minimal side effects = fewer the side effects means better public acceptance
Infrastructure = resources for producing storing and transporting vaccine are essential
Administration = proper timely vaccine administration is important (healthcare workers)
Herd immunity = majority of population need vaccine
What is herd immunity?
When majority of a population is vaccinated so even those not vaccinated have some protection
What happens when only a few individuals are vaccinated?
Most of population susceptible to disease, can be infected and transmit the pathogen onto others
results in many infected individuals
What happens when many individuals are vaccinated?
Most people immune to disease and can’t transmit the pathogen onto others
reduces chance of non-vaccinated individuals coming into contact with pathogen and fewer individuals infected
What factors prevent disease elimination via vaccines?
Individual immunity failures = people with weak immune systems (babies and elderly) may not withstand vaccines
Pre-immunity infection = individuals might contract disease post-vaccination before immunity develops becoming disease reservoirs
Pathogen mutation = rapid antigenic changes due to frequent mutations can make vaccines ineffective as the immune system can’t recognise pathogen’s new antigens
Pathogen variety = sheer number of pathogen variants can make developing universal effective vaccines difficult
Pathogen hiding = some pathogens can evade immune system by ‘hiding’ inside cells or inhabiting hard-to-reach body regions like intestines
Vaccine objections = personal, religious, ethical, or medical objections to vaccination can hinder disease eradication
What is antigenic variability and what does it mean?
When pathogens change their antigens
Makes it difficult to develop vaccines against some pathogens because if antigens change enough they will no longer be recognised by immune system
meaning memory cells produced from vaccination against one strain will not recognise antigens from another strain
How do antibiotics work?
Kill or inhibit bacterial growth by targeting bacterial enzymes and ribosomes used in metabolic reactions
this means they don’t damage human cells
What are some examples of how antibiotics affect bacteria?
- prevent synthesis of bacterial cell walls
- disrupt protein activity in cell membrane
- disrupt enzyme action
- prevent DNA synthesis
- prevent protein synthesis
Outline how antibiotic resistance develops via natural selection?
1) genetic mutations occur making some bacteria resistant to an antibiotic
2) when infection is treated with antibiotics resistant bacteria able to survive
3) resistant bacteria reproduce, passing antibiotic resistant allele to offspring
How can we reduce development of antibiotic resistant bacteria?
Choose appropriate antibiotic treatment = can be tested against bacterium strains to make sure they are effective in treating disease
Using only when needed = should only be prescribed for bacterial infections not viral
Avoiding wide-spectrum use = narrow-spectrum antibiotics (antibiotics specific to infection) is less likely to lead to antibiotic resistance
Ensuring patients complete course = ensures all bacteria are killed and so doesn’t give them chance to develop resistance
Avoid use in farming = reduces chance of bacteria becoming resistant
What are some examples of medicine?
Penicillin = antibiotic extracted from type of mould
Aspirin = painkiller based on compounds from willow bark
Digitalis = heart drug derived from foxglove plant
Why does medicine provide an argument for maintaining biodiversity?
Scientists haven’t yet discovered/analysed all organisms on earth so may be organisms that can provide treatments to currently incurable diseases
potential sources of new medicines need to be protected by maintaining biodiversity
What are 2 possible future medicine developments?
- personalised medicines
- synthetic biology
Describe personalised medicines?
Medicines tailored to individual’s DNA meaning patient’s genome is analysed before they are given any treatment and so drugs given are more likely to be effective and less likely to cause side effects.
Describe synthetic biology?
Involves use of genetic engineering to develop artificial proteins, cells, and microorganisms meaning bacteria or mammals can be modified to produce therapeutic drugs to treat certain diseases
