Possible Clues:

• Tiny worm
• A roundworm or threadworm
• Worm, harmless coiling round, getting into knot
• Long thin worm such as threadworm
• Parasite changes name to Mark Back from Spain
• It's tricky to demean a worm
• Make up name to give to Germany for parasite
• Worm that's harmless written up in dictionary
• Made note after chopping up worm
• Wheatworm, e.g.