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Webster 1913 Edition

Noun.

[So called from its shape.]

(Zool.)

A nematode worm (

Trichocephalus dispar

) often found parasitic in the human intestine. Its body is thickened posteriorly, but is very long and threadlike anteriorly.

whip worm ‎(plural whipworms)

Trichuris trichiura, a roundworm, causing trichuriasis when it infects a human large intestine.
- 2009, January 27, “Jane E. Brody”, in Babies Know: A Little Dirt Is Good for You:
  Dr. Elliott said that in Argentina, researchers found that patients with multiple sclerosis who were infected with the human whipworm had milder cases and fewer flare-ups of their disease over a period of four and a half years.

Trichuris trichiura