Gut methanogens
They keep hydrogen low so fermenting bacteria can keep working on fibre. Breath methane tests are research tools, not self-diagnosis.
Methanobrevibacter smithii is a common human-gut archaeon that consumes hydrogen and makes methane. That chemistry can shift how bacteria ferment fibre — ecology, not an infection label.
Detecting archaeal DNA on skin or in hospitals usually means environmental cells or reagents, not an outbreak of 'archaeal plague'.
Body interfaces
Rumen partners
Cows and other ruminants host dense methanogens. That alliance feeds people and also emits methane — a climate trade.
No pathogen list
Unlike bacteria, viruses and protozoa, archaea have no established infectious-disease chapter in textbooks.
Extremophile enzymes
Heat-stable polymerases from Thermococcus and relatives powered PCR after bacterial Taq. Concept only — not a protocol.
Sample confusion
Archaea in a clinical swab may be contaminants. Over-interpreting 16S hits wastes fear.
Livestock methane
Inhibiting rumen methanogens is a climate research topic. Diet and animal welfare sit in the same conversation.
Human relevance is methane, microbiome ecology and industrial enzymes from extremophiles — not a germ-theory villain.
Keep exploring
More in Tree of microbes
Bacteria
Single-celled prokaryotes with cell walls ? the oldest widespread life form, and both partners and pathogens.
Familiarity 95Viruses
Packets of DNA or RNA that are not cells — they replicate only inside living hosts.
Familiarity 96Fungi
A eukaryotic kingdom of yeasts, moulds and mushrooms — chitin walls, external digestion, partners of plants.
Familiarity 80Bacteriophages
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