Tuesday, October 26, 2021
Tuesday, October 19, 2021
Sunday, October 17, 2021
Answer to the Parasite Case of the Week 657: Plasmodium vivax
Thanks to all of the great comments on this case! There are so many classic features of P. vivax here, that it makes for a fabulous teaching slide. Florida Fan very nicely outlined all of the diagnostic features along with his thought process for coming to the final identification:
1/ The ring is fairly large, and the infected red cell is larger than the not infected. As such, there is a predilection for reticulocytes. Either P. vivax or P. ovale.
2/ The mature trophozoites are ameboid form, showing them to be highly Vivacious. More than likely P. vivax.
3/ The schizont in the third picture demonstrates more than twelve merozoites, P. ovale does not usually have that many. (on average, 8)
4/ The gametocyte in the fourth picture is not Falciform, it occupies almost the entire red cell. Though there is a little bit of fimbriation, all evidence gathered so far including the geographic area are consistent with an identification of P. vivax.
Here is a composite image of the 4 forms shown in this case:
Tuesday, October 5, 2021
It's time for our monthly case with Idzi Potters and the Institute of Tropical Medicine, Antwerp:
The following was seen in a urine sediment from a backpacker returning to Belgium following a 2-month's trip in Northern Senegal. During his travels, he reports being bitten by insects, drinking and eating local foods, and swimming in fresh water lakes. He is asymptomatic, but is concerned that he may has picked up a parasite along the way.
How would you interpret this finding?
Monday, October 4, 2021
Answer to the Parasite Case of the Week 656: mite, probable contaminant from the environment. Not likely of human medical significance.
As several readers noted, this mite is not one of the 2 human pathogenic mites, Sarcoptes scabei or Demodex. Instead, it is likely a mite from the environment, such as Dermatophagoides, the dust mite. The presence of many squamous epithelial cells in the background would support this idea:
You can read the following posts for more information for how to differentiate the various mites found in human specimens:
Case of the Week 634: Free-living mite found in stool
Case of the Week 196: Differentiating Sarcoptes scabei from other mites
Case of the Week 601: Key identifying features of Sarcoptes scabei