Answer: Not a Parasite; most consistent with a fiber containing proteinaceous deposits. One reader suggested obtaining additional information such as whether the patient was using an IUD or tampon. We can say with confidence that it is not a fungus or other microorganism.
Thank you all for writing in. I think that everyone recognized this as a non-parasite, and it was very interesting to hear the different hypotheses on what it actually is.
These little guys were a bit hard to make out due to their small size, but you can nicely see several characteristic features, including 6 legs (versus the 8 legs of nymphs and adults), and - if you squint - a U-shaped anal groove, consistent with Ixodes species.
As mentioned by FP in Burlington, VT, Borrelia burgdorferi, the agent of Lyme disease,is not transmitted tranovarially from mother to larva. Therefore, larvae are not infected and cannot transmit this bacterium to humans. Larvae can become infected when they take their first blood meal, after which they molt into nymphs. Therefore, unlike larvae, nymphs ARE capable of transmitting B. burgdorferi to humans, and present a particular hazard due to their small size which makes them easy to overlook.
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 Not shown here (since it was retracted into the worm) is the hooked proboscis from which the acanthocephalans get their name (Acanth is Greek for spiny or thorny).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.
Every week I will post a new Case, along with the answer to the previous case. Please feel free to write in with your answers, comments, and questions. Enjoy!
The Fine Print: Please note that all opinions expressed here are mine and not my employer. Information provided here is for medical education only. It is not intended as and does not substitute for medical advice. I do not accept medical consults from patients.