Sunday, September 14, 2014

Case of the Week 318

This week's case was generously donated by Florida Fan.  The following objects were seen in iodine-stained stool concentrates:



The identification was confirmed using a Modified Safranin method:


Sunday, September 7, 2014

Case of the Week 317

The following was seen on a Pap-stained endocervical smear.  Identification?

Thanks to Dr. Audrey Schuetz who donated this case!

Saturday, September 6, 2014

Answer to Case 317

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.

Sunday, August 24, 2014

Case of the Week 316

The following were found on a 10-year old boy from the northeastern United States.  Identification?

Saturday, August 23, 2014

Answer to Case 316

Answer:  Larval ticks, Ixodes species

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.

Monday, August 18, 2014

Case of the Week 315

The following structure was seen in the diaper of a 2 year old girl and sent to the lab for identification.  It is approximately 12 cm in length.

In the lab, the following eggs were expressed from the structure. They measure approximately 100 micrometers in length. Identification?

Sunday, August 17, 2014

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.