Answer to Case 727

 Answer to the Parasite Case of the Week 727: Hymenolepis diminuta

As noted by Lamia Gala on LinkedIn, "The distance between the outer and the inner shell is large with no polar filaments" which is consistent with H. diminuta. This is in contrast to Rodentolepis (formerly Hymenolepis) nana, which does have polar filaments between the outer and inner shell. H. diminuta is also slightly larger than R. nana, measuring 70-85 micrometers in greatest dimension (compared to 30-50 for R. nana). Florida Fan provided the helpful memory aid that the word "diminuta" is larger in size than "nana", which also applies to their eggs (thanks FF!). Here are some of the key morphologic features:

Thanks again to Dr. Bradbury for donating this lovely case!