Title text:
Under the two-domain system, anyone who punches you is technically an Archaean pathogen.
Transcript:
[Cueball, Megan, and White Hat are standing in a lab in front of a root-like phylogeny diagram, looking at it. Behind them is a desk with a microscope on it. There is a pile of items behind it and one item in front. From the plate on the microscope where the sample is, there is a star burst and a line going up to the text said by the sample.]
Cueball: It's weird how, despite being one of the main branches of the tree of life, no Archaea species are known to cause disease in humans.
Megan: Personally, I think it's because those gross methane breathers are too weird and incompetent to figure out how to hurt us even if they wanted to.
Archaea sample: Hey![Caption below the panel:]
Bad news: After overhearing a conversation in our lab, Archaea has finally started harming humans.
Source: https://xkcd.com/3095/
But there are eukayotic parasites. They are even closer to us. This on its own is not an explanation.