Biology (school) · Part 04
Health and disease
How germs make us ill and how the body and medicine fight back.
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- PathogenA microorganism that causes disease. The main types are bacteria, viruses, fungi and protists.
- Communicable diseaseA disease that can pass from one person or animal to another. Non-communicable diseases cannot.
- VectorAn animal that carries a pathogen from one host to another without usually being harmed itself.
- Immune systemThe body's defence against pathogens, based mostly on white blood cells.
- AntibodyA protein made by white blood cells that locks onto a particular pathogen and helps destroy it.
- VaccinationGiving a harmless form of a pathogen so the body learns to make antibodies before meeting the real thing.
- Herd immunityWhen enough people are vaccinated that a disease cannot spread easily, which protects even those who are not vaccinated.
- AntibioticA medicine that kills bacteria or stops them growing. It does not work against viruses.
- Antibiotic resistanceWhen bacteria evolve so that an antibiotic no longer kills them.
- Non-communicable diseaseAn illness that is not caused by a pathogen and cannot be passed on, such as heart disease or most cancers.