Welcome back to the Parasite Case of the Week! I post a new case every Monday, along with the answer to the previous week’s case. Here is our new case for this week.
A patient who recently returned from the Philippines presented with recurrent fevers, chills, and sweating. A peripheral blood smear showed the following (Giemsa stain, 1000x original magnification, oil immersion). Identification?
Parasite Case of the Week 11 can be seen HERE.
Answer: acanthocephales (thorny-headed worms) / phylum Acanthocephala
Congratulations to DrJ, “Anonymous” and Alasdair who got this correct right away. In the words of Alasdair “Acanthocephales, and such a beautiful parasite (if I may say so!)”.
It definitely is a striking appearing parasite, as the thorny head is quite apparent.
Acanthocephala are parasites of fish, as Alasdair mentioned, but they are also parasites of other vertebrates, including pigs, rats, and (rarely), humans. The most common ones to parasitize humans are Moniliformis moniliformis and Macracanthorhynchus birudinaceus.
Humans acquire this infection through ingestion of various beetles and cockroaches which are the intermediate host for these parasites. DrJ had some VERY good advice – this is another reason to avoid reality TV shows!
Thanks for writing in with your comments.
Informative video on how digital pathology is being used for medical student education at the University of New South Wales.
Welcome back to the Parasite Case of the Week! I post a new case every Monday, along with the answer to the previous week’s case. Here is our new case for this week.
The following helminth is a rare intestinal pathogen of humans. It embeds its spiny proboscis into the mucosa of the small intestinal, typically causing severe cramping and abdominal pain. Other symptoms include fever, nausea, vomiting, anorexia, weight loss, diarrhea, constipation or bloody stools. The morphology of the adult worm is classic:
Parasite Case of the Week 10 can be found HERE.
Answer: Trichuris trichiura otherwise known as the “whipworm” due to its whip-like shape. Notice that this example is a gravid female, with clearly identifiable eggs inside the uterus. Congratulations to all of the viewers who wrote in – either on the blog or via email.
The second part of the question was a bit tricky, but DrJ got it correct:
“the whip is the anterior end, which seems backwards to me because I always thought of it as a tail.” Most people get this wrong, since they tend to think of a worm body decreasing in diameter rather than increasing. However, it makes sense if you understand the life cycle of the adult female. The head is threaded into the mucosa of the large intestine, allowing the worm to feed on tissue secretions (best accomplished with a narrow anterior end). The posterior end is larger because it contains the gravid uterus, packed full of eggs. The adult female produces 2,000-20,000 eggs daily! Note that the posterior opening is wide enough to easily accommodate the release of these eggs. The images below nicely illustrate the anterior and posterior ends:
Shocking and tragic and you wonder how systems break down within a hospital to lead to these types of problems.
Having both worked and received care at VA hospitals in the past I have always found decent health care once you obtain access to the system and waited for an appointment.
Our veterans deserve better.
The CBS Evening News (6/16, story 5, 2:35, Glor) reported, “Capitol Hill is famous for holding hearings, but rarely have members of Congress been as shocked as they were” Tuesday, when “they got the results of a new report with this startling headline: More than 10,000 veterans who went in for checkups at several Southeast VA hospitals may have been exposed to HIV or other blood diseases.” According to CBS, over “10,000 veterans have now received letters warning them that the equipment the VA used for their colonoscopies may not have been properly sterilized. So far, six of those” vets “have tested positive for HIV, 13 for hepatitis B, and 34 for hepatitis C.”
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