Monday, February 2, 2009
Case of the Week 56
The following microscopic organisms were identified in water from a large African lake. They measure between 100-150 microns in length. Many of the residents who use this lake for bathing and drinking have enlarged abdomens. Identification?
Sunday, February 1, 2009
Answer to Case 56
Great answers to this week's case! All were correct:
"I think these itchy creatures are Schistosome cercaria - probably S. mansoni based on the [presumably] hepatomegalic abdomens of local bathers"
"I agree - they are the cercariae of S. mansoni (transmitted by the Biomphlaria Spp snail. "
Thank you to everyone who wrote in - both online and off.
These are indeed cercariae of Schistosoma spp. With the history I gave, you are correct in assuming that these belong to S. mansoni. However, it is important to remember that S. haematobium is also present in many parts of Africa. To my knowledge, you can not tell the cercariae of different species apart morphologically at this level.
The CDC has a nice map showing the distribution of S. haematobium (aka urinary schistosomiasis), S. mansoni (aka African hepatic/intestinal schistosomiasis), and where they overlap:
Click here for CDC Map
You'll notice from the map that much of Africa's population is at risk for schistosomiasis.
"I think these itchy creatures are Schistosome cercaria - probably S. mansoni based on the [presumably] hepatomegalic abdomens of local bathers"
"I agree - they are the cercariae of S. mansoni (transmitted by the Biomphlaria Spp snail. "
Thank you to everyone who wrote in - both online and off.
These are indeed cercariae of Schistosoma spp. With the history I gave, you are correct in assuming that these belong to S. mansoni. However, it is important to remember that S. haematobium is also present in many parts of Africa. To my knowledge, you can not tell the cercariae of different species apart morphologically at this level.
The CDC has a nice map showing the distribution of S. haematobium (aka urinary schistosomiasis), S. mansoni (aka African hepatic/intestinal schistosomiasis), and where they overlap:
Click here for CDC Map
You'll notice from the map that much of Africa's population is at risk for schistosomiasis.
Tuesday, January 27, 2009
Case of the Week 55
The following object was removed from the common bile duct during endoscopy. It is approximately 20 mm in length. Identification?
Monday, January 26, 2009
Answer to Case 55
Clonorchis sinensis (a.k.a. Oriental liver fluke) adult fluke.
Congratulations to everyone who wrote in with the correct answer!
The keys to identification of this fluke is its small size (10-25 mm long), characteristic gut bifurcation (arrows), and identification of 30 um eggs within the uterus (arrow head).
In this location, you would also want to exclude Fasciola hepatica. This fluke is larger than Clonorchis (30 mm long), has a much more complex gut branching system, and has much larger eggs.
Congratulations to everyone who wrote in with the correct answer!
The keys to identification of this fluke is its small size (10-25 mm long), characteristic gut bifurcation (arrows), and identification of 30 um eggs within the uterus (arrow head).
In this location, you would also want to exclude Fasciola hepatica. This fluke is larger than Clonorchis (30 mm long), has a much more complex gut branching system, and has much larger eggs.
Monday, January 19, 2009
Answer to Case 54
Answer: Cimex lectularis, the common bedbug.
Seen in this movie is an adult, several nymphs, and a single egg (bottom left corner).
Congratulations to Chris who got this one right away!
Seen in this movie is an adult, several nymphs, and a single egg (bottom left corner).
Congratulations to Chris who got this one right away!
Monday, January 12, 2009
Case of the Week 53
Shown is an iron-hematoxylin stain of a concentrated fecal preparation. What are the organisms shown and what is the significance of finding them?
Answer to Case 53
Answer: Iodamoeba butschlii
The key to identification of this ameba is the presence of the large dark nuclear karysome and the characteristic cytoplasmic vacuole.
Although this ameba is non-pathogenic in humans, its presence indicates that the patient has been exposed to fecally contaminated food or water. Therefore, a parasitic cause should not be exluded if it fits with the clinical presentation, and additional stool samples should be obtained for examination.
The key to identification of this ameba is the presence of the large dark nuclear karysome and the characteristic cytoplasmic vacuole.
Although this ameba is non-pathogenic in humans, its presence indicates that the patient has been exposed to fecally contaminated food or water. Therefore, a parasitic cause should not be exluded if it fits with the clinical presentation, and additional stool samples should be obtained for examination.
Monday, January 5, 2009
Case of the Week 52
Brain biopsy from an adult male with mental status changes. The 2 images are from the same microscopic field at different planes of focus, to demonstrate the range of findings. Identification? (CLICK ON IMAGES TO ENLARGE)
Sunday, January 4, 2009
Answer to Case 52
Answer: Toxoplasma gondii cyst and free tachyzoites. Congratulations to Alasdair, Kathryn, and the path resident who had the answer to this case! Notice the free tachyzoites that become clear as you focus up and down (arrow). One has a classic arc or 'banana' shape, diagnostic for this organism. CLICK ON IMAGE TO ENLARGE.
Subscribe to:
Posts (Atom)
