Wednesday, February 14, 2024

Get Ready for Filariae!

Dear Readers, I'm delighted to announce that March and April are Filariasis Months courtesy of Idzi Potters and the Institute of Tropical Medicine in Antwerp! 

Image by Blaine Mathison

You may want to brush up on your filariae/microfilariae diagnostic skills in preparation. Here are a few resources to help you:

  1.  World Health Organization Bench Aids for the Diagnosis of Filarial Infections. Available here: (see the section on filariasis near the bottom right of the page)
  2. CDC DPDx - Laboratory Identification of Parasites of Public Health Concern:
  3. Mathison, Couturier, and Pritt Diagnostic Identification and Differentiation of Microfilariae. J Clin Microbiol 2019.
Stay tuned for more!

Wednesday, February 7, 2024

Case of the Week 738

This week's case was donated by Dr. Sheldon Campbell. The following object was noted in fresh sole.   

Interestingly, it was still alive!

 What parasite is present here? 

After carefully removing the worms, the sole was breaded in cornmeal and fried. Looks delicious! 
Would you eat this?

Tuesday, February 6, 2024

Answer to Case 738

Answer to the Parasite Case of the Week 738:  Probable anisakid larva in fresh fish (sole). This is a great reminder to cook your fish well before eating! Alternatively, freeze it for 7 days at -20 C before eating it raw. The final dish that Dr. Campbell created looked quite tasty (sans worms). 

Not just a few readers noted that they might have some hesitation in eating the final product. 😂

One reader commented that generous application of lemon juice to the thawed fish prior to cooking does a great job in removing any live worms (and may result in a mass exodus!) However, this is only a good solution if you like the taste of lemon 🍋.

Thanks again to Dr. Campbell for sharing this great case!

Thursday, February 1, 2024

Case of the Week 737

 This week's case was generously donated by Dr. Richard Bradbury. The is a permanent mounted stool sample from a Gambian child with watery diarrhea. It is stained with iron haematoxylin; objects of interest are approximately 10-15 micrometers long. 

Check out the video for a 3D view and classic motility pattern!

Tuesday, January 30, 2024

Answer to Case 737

 Answer to the Parasite Case of the Week 737: Pentatrichomonas hominis trophozoites. 

P. hominis trophozoites have 5 flagella: 4 are directed anteriorly, while the 5th is directed posteriorly, forming the outer edge of an undulating membrane. This results in characteristic motility that Richard likes to describe as "a man trapped inside a plastic bag" (!)  I managed to capture a couple of still images from the video which show this phenomenon:

As noted by jebarner, P. hominis, as well as Enteromonas hominis,  Retortamonas intestinalis, and Chilomastix mesnili are non-pathogens and indicators of ingestion of fecally contaminated food or water. Therefore, the cause of this child's symptoms is unclear from this finding alone, and additional testing may be indicated.

Thanks again to Dr. Richard Bradbury for sharing this beautiful case!

Thursday, January 25, 2024

Case of the Week 736

The following arthropods were submitted to the lab for identification from a daycare center. What is your identification? What are the implications for this facility?

Wednesday, January 24, 2024

Answer to Case 736

Answer to the Parasite Case of the Week 736: Cimex sp., the human bedbug. Nymphs and an adult are present. The two species of Cimex that infest humans are C. lectularius (the common bedbug) and its tropical relative, C. hemipterus. As noted by Idzi and Florida Fan, the setae (hairs) are shorter than the width of the eye, which allows us to rule out other cimicids of birds and mammals that may temporarily infest human habitats.

Tanya Gravier provided a helpful link from the US Environmental Protection Agency on dealing with bedbug infestations in child care centers. As noted by Idzi, the risk is not with disease transmission, but rather with human bites at the center (e.g., during nap time), and with the possibility of bringing the infestation to the children's' homes.

Wednesday, January 17, 2024

Parasite Case of the Week 735

This week's case features a liver cyst (6 cm in diameter) that was removed and send to the parasitology laboratory for evaluation. The following images were taken by our fabulous Education Specialists, Felicity Norrie. Identification?


Tuesday, January 16, 2024

Answer to Case 735

 Answer to the Parasite Case of the Week 735: Echinococcus species.

The diagnosis can be made by the finding of the characteristic protoscoleces. As noted by Florida Fan, "On a closer look, the hooklets are clearly visible as well as the numerous calcareous particles. Since there is one cyst, the indication is that the agent is Echinococcus granulosis.

A Hamburg-based Oregon alumni further noted that for E. granulosus, "The liver is the most frequent location of echinococcal cysts (approx. 70% of cases). The lungs are the second most common location."

Thanks again to Felicity from my lab to taking these beautiful photos!

Wednesday, January 10, 2024

Case of the Week 734

Welcome to the first blog post of 2024! I had been particularly busy last year as I was serving as the Interim Chair of the Department of Laboratory Medicine and Pathology at Mayo Clinic. Now that the permanent Department Chair has arrived, I can go back to my 'day job' of Chair of Clinical Microbiology and Director of the Clinical Parasitology laboratory. I anticipate being able to go back to regular posting again as well. 

So without further ado, here is our case this week, courtesy of Heather Morris, the Parasitology Technical Specialist in my laboratory. The following objects were found in a concentrated wet preparation of stool, and measure approximately 20 micrometers in diameter. No patient history is available. What is your identification?