As I was raking and cleaning my bark covered hosta gardens

today I uncovered several little "colonies" of small(about one inch), thin grey worms. There were hundreds in each little colony. They lay just under the decomposing bark I had raked over. It was only about 48 degrees. They didn't move until I disturbed them a bit. Then some crawled under the bark.I'm worried about what kind of worms these are. They are in an area where there were many piles of wild rabbit dropping last spring. I'm concerned they could be a parasite that could infect my dogs..or even me! Does anyone have an idea what they could be?