Preventing and Treating Disease
Natural Active Immunity
- When T and B memory cells are produced after a primary infection, so that killer cells and antibodies can rapidly be produced upon second infection.
- Where antibodies in the mother's early milk (colostrum) provides immunity for the newborn when their immune system is too immature to produce antibodies, which are not digested by the baby and therefore give the baby the same level of immunity as its mother.
- Inoculated with a vaccine (a safe form of a pathogen) to stimulate to produce the production of antibodies.
- Antibodies are formed in one organism, then injected into the bloodstream of another organism to create temporary immunity for diseases such as rabies.
Vaccines and the Prevention of Epidemics
Medicines and Disease Management
- An epidemic is when a communicable disease spreads rapidly at a local or national level.
- A pandemic is when a communicable disease spreads rapidly at an international level.
- Vaccines provide long term immunity, so can be used at the start of a vaccination on mass to prevent spread to the wider population.
- When a significant number of people have been immunised, those without a vaccination are protected as it minimises the chance of an outbreak. This is herd immunity.
- Vaccinations in epidemics and pandemics often have to be changed frequently due to mutations leading to resistant strains.
- Flu is a disease which has caused epidemics. The A strain virus mutates regularly meaning vaccines need to be contantly modified, and people have little secondary immunity from one year to the next.
- People with compromised immune systems are vaccinated prior to an epidemic, and when an epidemic beings many more people are rapidly vaccinated to prevent spread. Free movement means people spread disease quickly, even across countries, meaning large vaccine stockpiles are in place to vaccinate multinationally if necessary.
- SARS was a flu-like disease spread from birds to people in 2012, spreading rapidly across countries. It was managed carefully, so minimised the number of deaths even without a vaccine.
- Malaria, a disease caused by protoctista. For more info, see 12.2
- HIV, a viral disease which compromises the immune system. For more info see 12.2
Medicines and Disease Management
- Medicine can be used to treat communicable and noncommunicable diseases. They alleviate symptoms and cure them. There are many sources of medicines.
Drug |
Source |
Action |
Penicillin |
Mould |
Antibiotic |
Docetaxel |
Yew trees |
Breast Cancer treatment |
Aspirin |
Willow Bark |
Painkiller, anti-coagulant, anti-pyretic, anti-inflammatory |
Prialt |
Cone snail venom |
Painkiller 1000x stronger than morphine |
Vancomycin |
Soil fungus |
Very strong antibiotic |
Digoxin |
Foxgloves |
Heart drug used to treat atrial fibrillation and failure |
Penicillin
- The first widely used effective and safe antibiotic used to cure bacterial diseases. Fleming discovered it in a mould in 1928 growing in Staphylococcus cultures. Florey and Chain developed an industrial procedure for mass extraction, saving countless lives.
- Computer modelling programmes allow scientists to build 3D models of key molecules in the body, antigens and pathogens. This allows models of potential drugs to be built up, and then ran through a database to find chemicals which may have effective action.
- Analysis of pathogenic genomes and cancer genes allows scientists to tackle disease with new drugs which attack their vulnerabilities.
- Pharmacogenetics are personalised drugs which work with an individuals genes and disease to create effective treatments. The human genome is rapidly analysed and drugs are developed to interact with the genetic basis of disease. This field of study is pharmacogenomics.
- Synthetic biology is using genetic engineering to create bacteria populations which would otherwise be too rare or expensive for use in drug production. Synthetic biology has also been used to genetically modify mammals to produce proteins in their milk.
- Nanotechnology is another strand of biotechnology where tiny non-natural particles are used e.g. to transport drugs to specific sites of a pathogen or tumour.
- As they are so effective, they were widely used, reducing child death rates due to communicable disease from 52% to 7%.
- Even in 2014 1 in 6 prescriptions are antibiotics, and are used for very minor infections. Now antibiotics are becoming less effective as mutated strains which are antibiotic resistant are naturally selected and become the most common strain.
- There are now bacteria immune to all antibiotics, and it is an evolutionary race between scientists and pathogens to beat it.
- MRSA and C. diff are examples of antibiotic resistant bacteria which can be fatal, and are particularly big problems in hospitals.
- MRSA is a bacterium carried by up to 30% of people on the skin or nose. It can lead to boils, abscesses and septicaemia. Once effectively treated with methicillin, mutation has lead to resistant strains.
- C. diff is a bacterium carried by about 5% of people in the gut. It produces toxins which damage the intestine lining leading to diarrhoea, bleeding and death. Can be fatal when commonly-used antibiotics kill off helpful gut bacteria leaving C. diff unregulated.
- Minimising the use of antibiotics
- Fully completing antibiotic courses, to ensure all bacteria are cured preventing development of resistant strains.
- Good hygiene reducing the spread of infection
- Looking for new sources of antibiotics in nature, and developing new drugs using computer modelling.