Answer to Parasite Case of the Week 4
You can view the Parasite Case of the Week 4 here.
Answer: Paragonimus spp.
As one writer points out, this specimen is on the smaller end of the spectrum, being just 5 mm in length (typical size 6-10 mm), but it otherwise has all of the characteristic features of a Paragonimus adult fluke. It is typically described grossly as a “coffee bean,” and has 2 suckers (as do all human flukes) – 1 ventral and 1 anterior. I’ve attempted to show the anterior sucker in the close-up image, but it’s a bit hard to make out. I’ve also given you a big hint with the history of hemoptysis. Paragonimus is the lung fluke, and creates cystic cavities in the lung parenchyma.
Kenny points out that 5mm (5,000,000 um) is pretty huge for a parasite egg, thus excluding this from the differential. In fact, the largest parasite eggs found in humans are those of the related flukes Fasciola and Fasciolopsis – however, they are less than 200 um in largest dimension – much smaller than the adults.
Thank you to all of the viewers who wrote in with their comments. Keep the comments coming!
No Comments Yet