By Lovey
Tyne And Wear,
United Kingdom 
after spreading horse manure on the garden i realised it is alive with 10 centimeter silver /see through worms/or whatever they are thickness of thread does any one know what they are ? are they harmful what treatment would you recommend grateful for any advice concerned thanks for your response
13 Nov, 2012
Answers
they sound like nematode worms and whilst I often find 5cm long ones in the soil naturally I've not seen any that long. Is the manure fresh ie straight from the horse or is it well rotted down? If fresh manure then they sound like parasites like MG says. if old manure then I suspect there will be no problems and they are a natural part of the natural recycling process.
14 Nov, 2012
Good point SBG - I was thinking of fresh horse manure.
14 Nov, 2012
thanks for your input much appreciated
14 Nov, 2012
I don't know but suspect these are parasitic worms that were passed in the horses faeces.
14 Nov, 2012