You were not far off. Anthrax sleeps in the soil until conditions become just right. The grazing animals drop like an ocean tide.
Wow...
I just envisioned something preserved from heat and cold, possible the buried clothes of an infected soldier, could have been wasting away in the soil...only to be foolishly unearthed by my project. I have no idea if this has any scientific merit.
I also used to be stationed at Fort Riley, and my very first day, I was required to take a fitness test. I did it on Camp Funston. Running a loop around the remnants of past barracks (probably WWII era), gulping in air, and pondering the Spanish Flu.