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!

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?

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.

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?

 

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!

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?

Answer to Case 734

 Answer to the Parasite Case of the Week 734: Entamoeba coli cysts. 

As noted by Florida Fan and Mary Lois Smorenburg noted, these cysts can be easily recognized by their large size and number of nuclei (>4). These are the most definitive features of this organism and allow it to be differentiated from similar-appearing Entamoeba spp. such as E. histolytica. Other supportive features pointed out by Mary Lois Smorenburg and Dr. Satishkumar Krishnan are the eccentric karyosome within each nucleus is and the irregular splinter shaped chromatoid body.

Thanks again to Heather Morris for donating our first case of 2024!