Answer to Case 315

Answer:  Moniliformis moniliformis, one of the principle agents of acanthocephaliasis.

The adult worm has a very characteristic morphologic appearance, which Heather A. aptly describes as resembling a "bendy straw" (see Here for information about bendy straws). Not shown here (since it was retracted into the worm) is the hooked proboscis from which the acanthocephalans get their name (Acanth is Greek for spiny or thorny).

The eggs are also characteristic, with a relatively large size (90-120 micrometers long) and internal larva with rostellar hooks.

Humans are accidental hosts, usually acquiring infection via ingestion of an infected insect such as a cockroach or beetle.  Moniliformis moniliformis does not always mature in humans, and when it does, it seldom produces eggs.  Therefore, this case is interesting in that a mature and gravid female was identified.