system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it that smallpox is stored at a “Biosafety Level 4”, yet Bubonic Plague is only kept at “Level 3” given both are very dangerous?

Why not have them both kept at the most restricted level?
gpt
Plague (*Yersinia pestis*) is comparatively less deadly by a significant amount. It is treatable with antibiotics with a very good survival rate, and not highly transmissible in the absence of disease reservoirs.  The big reservoirs for plague are wild animals, particularly rodents like prairie dogs and ground squirrels, and very few nations still have big flea problems in their human populations. It seems to be very geographically constrained (see the Plague Line on wikipedia). Also, modern day humans have evolved rather good inherent immunity, because genetic lines that were most vulnerable all ended a few hundo years ago.