Also known as Infectious agent, Germ
A pathogen is any organism capable of causing disease — a bacterium, a virus, a fungus or a parasite. The term covers the cause of an infection regardless of which kind of organism it is.
Pathogen is a category rather than a specific thing, and the category matters because treatment follows it. are living cells and can be killed by an antibiotic; a is not a cell at all and does not respond to one. Fungi and parasites each need their own class of drug again. Naming the type of pathogen is therefore the first useful step in an infection, and giving an antibiotic without it is how is driven.
| Type | What it is | Example illness |
|---|---|---|
| Bacterium | A single living cell | Urinary infection, typhoid |
| Virus | Genetic material in a protein coat | Influenza, dengue, hepatitis |
| Fungus | A yeast or mould | Thrush, ringworm |
| Parasite | An organism living on or in a host | Malaria, giardia |
Carrying a pathogen is not the same as being ill from it. Many live harmlessly on skin and in the gut and only cause disease when they reach somewhere they do not belong or when defences are weakened — which is why the same organism can be irrelevant in one person and dangerous in another.
Dermatology
Eczema is a leaky skin barrier plus an over-reactive immune system. Moisturiser is the treatment, not the afterthought — and steroid creams are safer than most people fear.
25 Aug 20269 min read
