I wanted to share my story in hopes it might help...
After experiencing the expected symptoms (cramps, bloody diareah, stools) my Gastroenterologist diagnosed me with at first proctitis..then colitis.
Had 2 colonoscopys, took for months medications that didnt help and caused headaches (sulfer based) The only medication that seemed to help was the cortison enema liquid.
This was over a year ago, and my symptoms have all gone away. My colitis went away by NOT riding the bus to work anymore. Now here me out, I have gone back to test my theory and have discovered the same result each time.
My case may be an isolated one, but intense, frequent vibrations (such as those from a vibrating message chair or pad, or in my case, a bus engine while stopped frequently in traffic) were causing my colitis symptoms. Since avoiding all vibrating devices..I am fine.
My digestive tract must be sensitive to constant vibrations.
I tested my theory several times by using a vibrating message cushion and/or taking the bus for several days..and the symptoms started up again. Hope this helps someone