Title: Archaea | Microbiology
Headings: Archaea
Archaea
Learning Objectives
Crenarchaeota
Think about It
Euryarchaeota
Think about It
Finding a Link Between Archaea and Disease
Key Concepts and Summary
Multiple Choice
Fill in the Blank
Think about It

Content: Many genera and species of Archaea are mesophiles, so they can live in human and animal microbiomes, although they rarely do. As we have learned, some methanogens exist in the human gastrointestinal tract. Yet we have no reliable evidence pointing to any archaean as the causative agent of any human disease. Still, scientists have attempted to find links between human disease and archaea. For example, in 2004, Lepp et al. presented evidence that an archaean called Methanobrevibacter oralis inhabits the gums of patients with periodontal disease. The authors suggested that the activity of these methanogens causes the disease. [ 6] However, it was subsequently shown that there was no causal relationship between M. oralis and periodontitis. It seems more likely that periodontal disease causes an enlargement of anaerobic regions in the mouth that are subsequently populated by M. oralis. [ 7]
There remains no good answer as to why archaea do not seem to be pathogenic, but scientists continue to speculate and hope to find the answer.