Bzzzzzzt! Wrong!
A 'human' can actually 'tolerate' 8,000 to 10,000 spores in his system - BEFORE his system is overtaken (overwhelmed) by Anthrax that is ...
See post #77 (per TomB) ...
I'm okay with anthrax being in my nose but I don't want it in my lungs. I might even get the cutaneous kind on purpose if anthrax gets common enough around here just so I'll have antibodies in my system against it.