Four Stages of Infectious Disease
1. Microorganism enters body
2. Reproduces rapidly, producing more microorganisms
3. Microorganisms produce toxins (poisonous substances) damaging cells and tissues
4. Toxins cause symptoms of infection (pain, stomach cramps), immune system's reaction to infection also causes symptoms (fever)
Time between exposure to microorganism and development of symptoms is the incubation period.
Antiseptics and Antibiotics
Chemicals to destroy bacteria or stop them growing
Antiseptics used outside body to clean wounds and surfaces, prevent infection rather than treating it
Many household products contain antiseptics (bathroom cleaners), also used in hospitals and surgeries to prevent infections like MRSA
Antibiotics are drugs used inside body usually taken as pill or injection, treat already infected, can only kill bacteria, does not affect virus
Evolution of Bacteria
Random mutations in bacteria DNA leads to changes in bacteria's characteristics, less affected by antibiotics
Bacteria with these genes better at surviving and reproducing in a host being treat to get rid of infection
Leads to gene for antibiotic resistance passed on to offspring - natural selection
Gene spreads and bcomes common in population of bacteria over time
Bacteria resistant to antibiotics (MRSA) makes infections harder to treat
How to Prevent
More antibiotics used, bigger the problem of antibiotic-resistance
Only prescribe when necesary - antibiotics do not cause resistance, but create situation where naturally resistant bacteria have an advantage and so increase, if antibiotics won't do you any good, it's pointless to take them, and could harm others.
Take all antibiotics prescribed - lots of people stop taking antibiotics as soon as they feel better but can lead to risk of antibiotic resistant bacteria emerging, must complete dose.