Answer to Case 642
Answer to theParasite Case of the Week 642:Plasmodiumsp. infection with relatively high (1%) parasitemia; differential diagnosis includes mixedP. falciparum/P. malariaeinfection andP. knowlesiinfection. Recommend nucleic acid amplification testing for definitive identification.PCR testing confirmed that this wasP. knowlesiinfection!This interesting case highlights the difficulty in diagnosingP. knowlesiinfection, given that many of its key morphologic features in humans overlap with those ofP. falciparumandP. malariae. LikeP. falciparum,high parasitemias may be observed, and thin delicate rings - occasionally with dou...
Source: Creepy Dreadful Wonderful Parasites - June 6, 2021 Category: Parasitology Source Type: blogs

Case of the Week 641
This week ' s case was generously donated by Dr. Alexander Fenwick and includes some beautiful images. The following objects were seen in a sputum specimen from a patient living in Eastern Kentucky. This patient was receiving corticosteroid therapy for poorly-controlled COPD. Identification?Gram stain (10x and 100x magnification)Wet mount: (Source: Creepy Dreadful Wonderful Parasites)
Source: Creepy Dreadful Wonderful Parasites - June 1, 2021 Category: Parasitology Source Type: blogs

Answer to Case 641
 Answer to theParasite Case of Week 641:Strongyloides stercoralisL3 (filariform) larvae.As mentioned in the comments, other items on the differential diagnosis include larvae of the hookworms andAscaris lumbricoides.The larvae of these nematodes are only rarely seen during the initial stage of infection, in which larvae migrate to the lung before reaching their permanent destination in the intestinal tract. For that reason, it is very rare to identify them in clinical specimens. In comparison,S. stercoralishas an ongoing autoinfection cycle in humans which results in recurrent migration of L3 larvae through the lung. ...
Source: Creepy Dreadful Wonderful Parasites - May 30, 2021 Category: Parasitology Source Type: blogs

Case of the Week 640
Here ' s a fun case for you all - submitted for arthropod identification. Thoughts? (Source: Creepy Dreadful Wonderful Parasites)
Source: Creepy Dreadful Wonderful Parasites - May 25, 2021 Category: Parasitology Source Type: blogs

Answer to Case 640
 Answer to theParasite Case of the Week 640: PseudoscorpionDespite the scary look of this arthropod ' s front pincers (enlarged pedipalps), it is not a scorpion and does not harm humans. In fact, pseudoscorpions can be helpful; Dwight Ferris pointed out that they feed on other arthropods pests that you don ' t want in your house such as carpet beetles, book lice, ants and clothes moths. The main way to tell a pseudoscorpion apart from a true scorpion is that the former is much smaller (usually< 5 mm long) and lacks a telson (venom bulb) and aculeus (stinger) at the end of their abdomen. Of note, both pseudosco...
Source: Creepy Dreadful Wonderful Parasites - May 23, 2021 Category: Parasitology Source Type: blogs

Case of the Week 639
This week ' s case was generously donated by Drs. Timothy Y. Chou and Roberta J. Seidman. The specimen is a corneal biopsy in an elderly woman who had been receiving ocular steroid treatment (but no systemic immunocompromising agents). The patient went on to develop bilateral punctate keratitis, and corneal biopsy showed the following objects:H&E, 600x and 1000xTissue Gram stain, 1000xWhat is the most likely diagnosis? What additional studies would you recommend to confirm the diagnosis? (Source: Creepy Dreadful Wonderful Parasites)
Source: Creepy Dreadful Wonderful Parasites - May 17, 2021 Category: Parasitology Source Type: blogs

Answer to Case 639
Answer to Case of the Week 639: Microsporidia spores. As many of you noted, the differential diagnosis includesToxoplasma gondiitachyzoites. Here are some of the key morphologic features:Location in the cornea. [T. gondiiis usually found in the posterior chamber of the eye (e.g., retina)]Small oval shape with well-defined contours on H&E:Unfortunately,T. gondiitachyzoites are much less defined on H&E - they can be very difficult to see. They often don ' t even have a nice crescent shape like we seen on Giemsa-stained air-dried impression smears. They often just look like little blobs in tissue.Strong Gram...
Source: Creepy Dreadful Wonderful Parasites - May 16, 2021 Category: Parasitology Source Type: blogs

Case of the Week 638
This week ' s case was generously donated from Drs. Cynthia Magro and Lars Westblade. The following object was identified in an hematoxylin and eosin stained tissue section of toenail in a patient with onychomycosis. Identification? (Source: Creepy Dreadful Wonderful Parasites)
Source: Creepy Dreadful Wonderful Parasites - May 11, 2021 Category: Parasitology Source Type: blogs

Answer to Case 638
Answer to theParasite Case of the Week 638: Not a human parasite; seed.This is a small seed that likely became embedded in the nail. Botanist Dr. Mary Parker commented that " I would rule out a grass/cereal seed, as there is clearly an embryo (radicle and cotyledon) embedded in starchy endosperm, the whole surrounded by an epidermis and cuticle. The central vascular strand can be seen in the radicle, with pro-vascular cells in the cotyledon. It must be a small seed but in the absence of a scale bar, it is difficult to say more. "  I learned from Dr. Cynthia Magro who donated this case that the patient has onychomycosi...
Source: Creepy Dreadful Wonderful Parasites - May 9, 2021 Category: Parasitology Source Type: blogs

Case of the Week 637
Welcome back to the first Monday of the month! It ' s time for our monthly case from Idzi Potters and theInstitute of Tropical Medicine in Antwerp. The following structures were found in a stool specimen from a patient originally from the Democratic Republic of the Congo. He presented with long standing diarrhea (occasionally bloody), intermittent abdominal pain, decreased appetite and unintentional weight loss. They are approximately 200 micrometers long.What is the most likely identification? (Source: Creepy Dreadful Wonderful Parasites)
Source: Creepy Dreadful Wonderful Parasites - May 3, 2021 Category: Parasitology Source Type: blogs

Answer to Case 637
 Answer to Parasite Case of the Week 637:Schistosoma intercalatumThis was definitely a tricky case! The eggs strongly resemble those ofSchistosoma haematobium,but stool would be an unusual source for this parasite, and the eggs in this case are larger than what would be expected for S. haematobium(usual size is 110 to 170 micrometers long). In comparison, S. intercalatumeggs are most often found in stool and measure 140 to 240 micrometers long. They also characteristically have an equatorial bulge as seen in one of the images from this case:Of note, Schistosoma intercalatumhas a very limited geographic ...
Source: Creepy Dreadful Wonderful Parasites - May 2, 2021 Category: Parasitology Source Type: blogs

Case of the Week 636
This week ' s case was donated by one of our intrepid infectious diseases fellows, Dr. Geno Tai, who was travelling across country and found these arthropods in his lodging. Identification? Photos and video courtesy of his friend and travel-mate, Dr. Chris Hwang. (Source: Creepy Dreadful Wonderful Parasites)
Source: Creepy Dreadful Wonderful Parasites - April 26, 2021 Category: Parasitology Source Type: blogs

Answer to Case 636
 Answer to theParasite Case of the Week 636:Cimexsp. Given the location (hotel in North America), this is most likelyCimex lectularis,the common bed bug. However, we would want to have a closer examination to be sure. It looks like we have a couple of different life cycle stages here. Also, at least one squished well-fed one - nice job Geno!  Hereis a good resource for information. (Source: Creepy Dreadful Wonderful Parasites)
Source: Creepy Dreadful Wonderful Parasites - April 25, 2021 Category: Parasitology Source Type: blogs

Case of the Week 635
This week ' s case features a fun finding in a concentrated wet prep of stool stained with iodine. The case and photograph are from Blaine Mathison and Madison Sant. The object below measures approximately 35 micrometers in diameter. Identification? (Source: Creepy Dreadful Wonderful Parasites)
Source: Creepy Dreadful Wonderful Parasites - April 19, 2021 Category: Parasitology Source Type: blogs

Answer to Case 635
 Answer:Entamoeba coli,supernucleate cyst. TypicalE. colicysts have 8 nuclei, but I ' m counting at least 18 nuclei in this one. My first thought when I saw this photograph was - holy molyE. coli! Thanks again to Blaine and Madison for donating this fun case. (Source: Creepy Dreadful Wonderful Parasites)
Source: Creepy Dreadful Wonderful Parasites - April 18, 2021 Category: Parasitology Source Type: blogs