Headline virus
News English often uses virus for any outbreak. Ask whether the story means a virus, a bacterium, or an unknown.
Darker cells mean a higher score for this topic on that metric.
Familiarity96
Medical weight88
Benefit25
Risk82
Research94
Live debate55
LessMore
Each bar is a 0-100 atlas score for this topic, not a timeline.
Both scores stay visible. Drag the slider to emphasize Benefit or Risk.
Benefit
Risk
Familiarity
96%
Milestones in order. This is history, not a weekly activity grid.
- Ivanovsky's filter
- Beijerinck's fluidum
- Rous sarcoma
- Stanley crystallises TMV
- Hershey–Chase
- Polio vaccine licensed (US)
- HIV identified
- SARS-CoV outbreak
Last reviewed Sources & creditsMedia creditsMethodology
Encounter route pick
Pick one encounter or route already written on this topic and reopen it next time.
Classroom literacy — not a lab result, diagnosis or outbreak alert.
Route on this page
One encounter scale
Scale literacy. Not a lab result or a diagnosis.
Quick facts
20–300 nm for most; some giant viruses exceed 400 nmTypical size
DNA or RNA, not a free-living cellGenome
1892 — Ivanovsky, tobacco mosaicFirst filterable agent
On the order of 10^31 particles in estimatesEarth abundance
None independent — host ribosomes requiredMetabolism
Do not target virions; they target bacteriaAntibiotics
Viruses are not cells. They are DNA or RNA genomes in protein coats — sometimes wrapped in a stolen membrane — that can make more of themselves only inside a living host.
That host rule explains the whole public story: vaccines train recognition, antibiotics miss the target, and most viral lineages on Earth never notice a human being.
This atlas treats viruses as a branch of the microbial world, not a synonym for 'the worst disease'. Later topics cover phages, vaccines and everyday encounters.
96FamiliarityEditorial 0–100 browsing aid within this atlas.
88Medical weightEditorial 0–100 browsing aid within this atlas.
25BenefitEditorial 0–100 browsing aid within this atlas.
82RiskEditorial 0–100 browsing aid within this atlas.
Viruses — concrete atlas depth on Tool-Lifes.
Viruses — concrete atlas depth on Tool-Lifes.
A particle, not a cell
Headline English says virus the way older copy said germ. The local job is to keep virus, variant and bacteria from collapsing.
Variant in public copy
Variant is a surveillance word, not a moral grade. See the mutation topic for how names are minted.
Public-health desks
English clinic advice repeats: antibiotics do not treat typical viral colds. That sentence is the local public-health hook.
The profile
- Familiarity96
- Medical weight88
- Benefit25
- Risk82
- Research94
- Live debate55
Risk
Packets of DNA or RNA that are not cells — they replicate only inside living hosts.
Seven ways into this topic
Related on the scale
Slide across the log scale — teaching sizes, not lab measurements.
Frequently asked questions
Where should I start with Viruses?
Read Identity → How they live → Body & health, then use compare rails.
Is this page advice for Viruses?
Public-health education — not a care plan, prescription, or outbreak briefing.
What does the local lens add?
It names everyday desks for Tree of microbes before English norms look universal.
Are the scores a ranking of Viruses?
No — editorial 0–100 browsing aids inside this atlas only.
How do I compare Viruses to neighbours?
Use related cards and best-of / quiz rails after the first three chapters.
Which chapter is densest?
How they live and Body & health carry mechanisms; skim Identity first.
Can I cite these scores externally?
Treat them as atlas orientation, not certificates or forecasts.
What should I check before acting?
Primary desks for Tree of microbes: public-health desks and lab teaching frames.
Sources & research
More in Tree of microbes
Bacteria
Single-celled prokaryotes with cell walls — the oldest widespread life form, and both partners and pathogens.
Familiarity 95Fungi
A eukaryotic kingdom of yeasts, moulds and mushrooms — chitin walls, external digestion, partners of plants.
Familiarity 80Archaea
A prokaryotic domain that is not bacteria — methanogens, extremophiles and no known human pathogens.
Familiarity 35Bacteriophages
Viruses that infect bacteria — Earth's most abundant biological entities, and a concept-level idea in medicine.
Familiarity 42Protozoa
Motile unicellular eukaryotes — a teaching grade that includes pond ciliates and a minority of serious parasites.
Familiarity 58