Case guesses:

Wink writes:

My old copy of Basic Clinical Parasitology says that Enterobius vermicularis can be up to 13 mm long. I think a scared patient could round that up to an inch. Common things being common, I’m guessing pinworms in the 23 year-old female traveler. (However, I am probably wrong, because Daniel wouldn’t throw the same pitch twice!)

Wink Weinberg

Allan writes:

Dear Doctors TWIP,

Greetings from the Big Island of Hawaii, where it was a chilly 20”C when I got up this morning, but has warmed to a nice 27”C by noon.

We have our own small outbreak here. In mid October I was called in by a local clinic to diagnose a patient with a fever and a strange rash that I’m told has become our first confirmed autochthonous or locally acquired case of Dengue on our island in 70 years. I asked them to test for dengue and chikungunya since “everyone knows we don’t have dengue here.”  Now we’re up to some 215 confirmed cases of Dengue, although our State Public Health, County Civil Defense and Health Department have done a great job jumping on it quickly: a big promotion to “Fight the Bite” and reduce mosquito bites, three limited permethrin (Aqua-Reslin) sprayings for adult mosquitoes within 200 yards around a confirmed case over the 10 days or so it takes mosquitoes themselves to become infectious, since our two local aedes species that carry dengue don’t generally fly more than 150 yards; and biological control pellets (Mosquito Bits) that contain dehydrated mosquito-cidal bacteria (Bacillus thuringiensis Israelensis), which can be put in tires and other mosquito habitat difficult to otherwise eliminate. The last report is they are monitoring only one confirmed case who could still be infectious, but its the asymptomatic but infectious cases you still worry about.


I’ve twice spent 3 months working in Uganda, just south of Southern Sudan where your patient had worked.

And like your patient, I am a strong advocate of adventurous eating and love Ethiopian food!

Niter kibbeh, their spiced clarified butter is one of Ethiopia’s wonderful secrets and I have NO problem loving meat in their stir-fries (tibs) or stews (wats). But I would want the raw beef in Kitfo and Kurt to be from a very trusted food supplier and cook… an Ethiopian friend in Baltimore perhaps, but maybe not in rural Ethiopia.

As a diagnostic differential, I went down the list of human helminths:


All you need to see a Pinworm infection (Enterobius vermicularis) is a bit of sticky clear tape, but

(1) I doubt they would be described without also mentioning intense itching, and

(2) adult Pinworms would be much smaller, perhaps, 1/8 inch versus the 1 inch worm described.


I have seen many live active Ascaris lumbricoides, but usually only subsequent to having given older deworming medication and they are much larger (2-5 inches)

Whipworms Trichuris trichiura: about the right size, but you never see the actual worms unless there’s a rectal prolapse in young kids.

Hookworms: A female hookworm could be that size, but I have only seen hookworms, in kids with a prolapsed rectum, which was not described in this case.

You don’t see much threadworm (strongyloidiasis) in Africa, much more in Asia.

Flukes are round and often the size described. If the Kitfo contained ground beef liver or lungs, could a beef lung fluke or liver fluke have been ingested? Sure.

Would it still be active after passing through the human intestinal track? I don’t think so… and especially would not still be emerging a month later.

However, in Uganda, I recall seeing active white worms of about the size mentioned emerging from the stool of cattle. I was told they were Moniezia expansa, a tapeworm whose primary hosts are sheep, goats, cattle and perhaps pigs, but were more likely Monieza benedeni, who are more common in cattle.  While officially a flatworm, at this stage they appear fairly round.

While there are reported cases of human infection with Moniezia, ostensibly from food contamination, it is rare…. but that rabbit trail of thought did bring me around to Tania sergeant or beef tapeworm which can cause an ongoing human infection.

The cysts in the beef muscle could have easily found their way into minced Ethiopian Kitfo or Kurt, which is then ingested and over the next couple months the cysts become happy adult tape worms in the human intestine. In an otherwise well nourished person, the only symptom may be that of feeling bloated or having mild gastric symptoms…. until the egg carrying segments actively crawl out… which is usually accompanied by itching, which was not described, but they would be about the right length and color.

Still this fits the picture best, so my guess is Tania sergeant  with the outside possibility of Moniezia.

In the US, a single, one gram dose of Niclosamide will usually prove effective, although in Ethiopia they are more likely to use praziquantel.

Fortunately, it should be easily treated with little chance of other complications.

I will be delighted to be proven wrong as I have learned so much from your podcast.

What a great 100th podcast and start of another year of TWIP!

Keep up the great work. You are an inspiration and make my commute now downright enjoyable. After listening to your podcast with my girls this morning on the way to school, my 12 year old announced tonight at dinner that she wants to do her upcoming science fair poster on possible CRISPR / CAS applications on dengue mosquitoes!

Best regards,

Allan Robbins

Kailua-Kona, Hawaii

Venkat writes:

Hello Twippees,

I think the girl who returned from Sudan could have acquired Ascaris lumbricoides when she was serving refugees in Sudan. It is very common in such areas of poor sanitation. I don’t think it could have been anything to do with her swimming in the waters or eating local food.

Thanks to your inspiring podcast series, my friend (a public health postgraduate) and I (trainee in clinical infec disease) are planning to start our own podcast in my native language, Tamil, which is spoken in southern India. Although we are not experts in the field like you people, we figured this will be a great learning experience for us as well as our audience, if we could find some 🙂

Dr Vincent, I read your articles in ASM journals about the benefits of podcasting. I was wondering how managed to set the whole thing up at the beginning? Did you pay someone to do it, or by yourselves? I would be glad if you come provide some tips regarding this.

Again, thanks to you all for being such an inspiration.

Congratulations to TWiP for the 100th episode. I wish a long life to TWiP, TWiM and TWiV!


Mike writes:

I’m going for Trichuriasis (Trichuris trichiura) commonly known as human whipworm.

I’ve got to break my losing streak.

Mike from Orygun

Anne writes:

I am venturing a diagnosis of Taenia saginata infection. The description of the wriggling parasites sounded very much like that of cats with the ‘flea tapeworm’ Dipylidium caninum although larger. ‘Crawling rice grains’ is the usual description from pet owners. I consulted Dickson’s Parasitic Diseases (3rd edition) but was unable to determine proglottid size. The description of the proglottids crawling down the patient’s thigh, producing a tickling sensation was somewhat unnerving.


Beaverton, Oregon

Robin writes:

One inch adult enteric nematodes are Oesophagostomum, Ternidens diminutus and Strongyloides, none of which present as adults in a relatively benign fashion in human stool.

While there may well be yet another (wild) enteric nematode that presents benignly as one inch adults in human stool, a large load of immature Ascaris could also conceivably do so, if possible wild ones are excluded. It would also be consistent with the report of “up to” two inches.

NAACP is – or maybe was – the standard mnemonic for causes of eosinophilia: neoplasm, Addison’s, allergy, connective tissue disease and parasites.


Robin writes:

5cm nematodes passed in stool

While Trichuris is not usually passed spontaneously in the stool, treatment with non-prescription anthelminthics might cause this.

Tejas writes:

Hello doctors namaste and congratulations on episode 100 of TWiP. I am a microbiology undergrad and have been an audience to this great podcast for about an year now, but this would be the first time writing in for me. The weather here in Mumbai is weird and fluctuating a lot and as a result I am down with the common cold. I have barely scratched the surface of the micro world and it has grabbed my interest like nothing else before and TWiP is just helping with that. This trio really entertains as well as enlightens me every time I tune into TWiP. As all always thank you Dr Griffin for another great case and my guess for this one would be Taenia saginata as its infection is pretty common in Africa and with the ingestion of kitfo which is essentially raw beef, this would explain a lot and the infection is essentially asymptomatic unless it is just way too much in which case it presents with some severe symptoms. The diagnosis is via examination of the stool, in addition to this the body of the worm is also white in colour. It might be worthwhile to point out that this is a tapeworm though. I am not sure of this diagnosis but it is definitely worth the try. Keep twipping away. I hope you continue the podcast for as long as you can.

Ramon writes:

Sugested pick of the week:

Ramón Canet, MD

Internal Medicine dept

Hospital Can Misses. Ibiza. Spain

David writes:

About the 53 year old woman visiting from bolivia I believe that she has a fasciola fluke infection. What amazes me however is that her eosinophils are getting a reading. From what I have read the eosinophils simply don’t activate due to the flukes ability to disable the dendritic presentation of the antigens. I would prescribe a round of triclabendazole to help this patient after the ultrasounds. Most radiologists don’t know how to diagnose and infection anyways so I would prescribe the medicine and see if she eliminates the flukes.


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