Dear Readers, I can't believe that I am celebrating my 700th post! In honor of this day, I am featuring the image that started it all - my 'mascot' of sorts. Can anyone tell me what this is?
Saturday, October 29, 2022
Answer: Shown here is the head and front legs of Pediculus humanus, the human body/head louse. It's very hard to tell the gender from just the portion that I showed you, so here is an image of the complete body. As you can tell from the pointed posterior, this is a male rather than a female. Thanks to all who hazarded a guess!
Thank you all for the kind words of support for reaching this milestone as well. I couldn't do it without you. Your comments, contributed cases and support over the year continue to inspire me, and I always learn something from each case.
Tuesday, October 25, 2022
Greetings from South Korea! This week's case shows an important parasite in this country, shown to be found in up to 8.4% of residents living along 5 major rivers in South Korea in a recent survey. What parasite is shown here?
Bonus questions: what are the potential health implications for patients with long-standing infection with this parasite?
Sunday, October 23, 2022
Answer: Clonorchis sinensis/Opisthorchis eggs. The location (South Korea) is consistent with C. sinensis.
As noted by Sam, "Both eggs have an abopercular knob and an obvious operculum. So these could be eggs of either Clonorchis sinensis or Opisthorchis species (both liver flukes). We can't differentiate based on morphology, but based on the patient being from/living in South Korea, we can likely narrow the identification down to Clonorchis sinensis, as Korea is an endemic region for this parasite. Whereas Opisthorichis viverrini is endemic to South East Asia (i.e, Vietnam, Cambodia, Laos, Thailand). Biliary complications can arise from long term Clonorchis sinensis infections, including cholangiocarcinoma." Other complications, as noted by Eddy Martinez, are cholangitis, cholelithiasis, cholecystitis, and pancreatitis. The shouldered operculum and small size of the eggs (around 30 micrometers long) are nicely appreciated in this case:
The eggs of Metagonimus yokogawai and Heterophyes heterophyes also have a similar appearance and should be considered in the differential diagnosis. They are not found in South Korea, however, and can be excluded in this case.
Tuesday, October 11, 2022
This week's case is from Dr. Richard Bradbury and his colleague. The following "worms" were removed from the buttocks and left thigh of a 4 year old girl in The Gambia, West Africa. Identification?
Sunday, October 9, 2022
Answer to Parasite Case of the Week 698: Cutaneous/furuncular myiasis due to Cordylobia anthropophaga (a.k.a. the tumbu or mango fly). As nicely described by Florida Fan, the spiny body, sinuous posterior slits without distinguishable peritreme, and the geographic location all are consistent with C. anthropophaga. Idzi P. added that "the evenly distributed and pigmented cuticular spines are also supportive of this identification." The presence of 3 slits indicates that this is a third stage larva, which allows for identification using commonly-available identification keys.
Here is a closer view of the posterior spiracles, showing the characteristic posterior slits:
Cordylobia anthropophaga has a fascinating life cycle. The adult female fly lays 500-700 eggs at a time in dry soil contaminated with urine and feces. They have also been known to lay their eggs on clothing that are hung out to dry. Larvae hatch from the eggs and can remain alive in the environment for up to 2 weeks, residing just below the surface of the soil . When the soil is disturbed by a potential host, the larvae quickly emerge, and each can penetrate the skin of the host and create a cavity in which to live, feed, and mature. The posterior end of the larva faces outward within the resultant furuncle to allow for respiration through the posterior spiracles. Larvae go through 3 stages (referred to as L1, L2, L3) over a period of 8 or more days, and will then drop from the host and pupate in the environment. In warm climates, the adult fly hatches after 10-11 days.
I will always remember the story from a family member who went on a lavish African safari several decades ago and was somewhat embarrassed when the housekeeper insisted on ironing her undergarments after they had been hanging on the line to dry. When she told the housekeeper not to bother, she was very quickly informed why this was necessary - in very graphic detail! (You can see a rather disturbing case of furuncular myiasis of the breast HERE).
Thanks again to Dr. Richard Bradbury for donating this fascinating case.
Monday, October 3, 2022
It's time for our monthly case from Idzi Potters and the Institute of Tropical Medicine, Antwerp!
The following structure was seen in a lugol-stained wet preparation of concentrated feces.
The corresponding iron hematoxylin stained fecal smear showed the following:
Sunday, October 2, 2022
Answer to Parasite Case of the Week 697: Entamoeba hartmanni cyst and trophozoite.
As noted by Florida Fan, Clinton White, TheOracle, and many others, the trophozoite has the classic Entamoeba-type chromatin pattern (peripheral ring of condensed chromatin and a central dot-like karyosome), whereas the size of the troph and cyst are characteristic of Entamoeba hartmanni. Thanks again to Idzi Potters for donation of another excellent case!