Case guesses:

Nita writes:


   Hello to the TWIP-tastic peeps! I missed Dr. Despommier on the last episode, but I had a great time listening in! For our last case 132, I did have a fun memory to share! Growing up in Taiwan during my grade school years, we would receive packets of slippets that had a target bulls-eye pattern that was sticky on one side to bring home. Every family member would stick it on their butts to essentially perform their own Scotch-tape exam, cover the sticky side with the clear plastic to keep whatever you stuck on your butt on the adhesive end, and bring them to school. Picture of what this looked like is in the link here:

   I have no idea who looks at all these packets, but I would guess someone in the health office (maybe the nurses or local doctor assigned to the school) would be the sad fellow appointed to this wriggling mess.

   Onto my guess for case 133, the young Haitian child suffering from failure to thrive with observed motile worms in feces opens the can of worms to a few possible differentials, notably, ascaris lumbricoides, hookworm, or whipworm. From this list, I think ascaris lumbricoides is probably the most likely answer. This is an intestinal parasite that clogs up the lymphatic system, which can explain our patient’s edema. It can also result in intestinal obstruction, which can manifest in the protuberant belly as this worm can multiply and grow quite large (as seen in the photographed preserved jar from the Meguro parasitological museum via my sneaky photo skills). Nutritional deficiency can result from the obstruction and the energy siphoning from the worms. The patient likely was infected through the fecal route with poor sanitary conditions. With earth floors, it is easy to track in infected dirt or with unsanitized water source, the worms may also be ingested. Usually, the worms are also found in the pulmonary system (as is the hookworm).

Diagnosis is done by stool microscopy, and I think the standard treatment can be albendazole 400mg PO or mebendazole 500mg for those older than 2 years old. Also, “everting uterus” from the pinworm made me giggle. What a great way to describe this! Thanks again for continuing the awesome podcast.

David writes:

Dear Hosts,

Judging from Daniel’s hints regarding a certain image in a book as well as adding up the factors described in the current case (abdominal discomfort, distended belly, lack of nutrition compared to her sister, long motile worm in the feces), I will venture a guess that this young girl has been infected with Ascaris lumbricoides. She most likely contracted the parasite eggs after coming into contact with soil or water contaminated with feces from her impoverished environment. I came across a link that states Ascaris is one of the most common worm infections in Haiti (, and I hope this little girl received the treatment she needed (treatment for this parasite [ascaricides] are albendazole, mebendazole, levamisole, pyrantel pamoate).

Thank you once again for the informative and entertaining podcasts

Sincerely, David P.

Molecular Helminthology Lab

Tufts Cummings School of Veterinary Medicine

Wink writes:

Dear TWIP Team,

I found the picture in your fantastic text, so I must say ascariasis with a heavy worm burden. But I was wondering if strongyloidiasis would also fit this case. I was thinking about the latter because of the edema on the abdomen and wondering if the immune-deficiency of malnutrition is sufficient to lead to hyper-infection.

Wink Weinberg (Atlanta)

Trudy writes:

Dear TWiPpers,

I think the girl is infected with Strongyloides stercoralis.  She probably contracted the parasite from the dirt floor in her home, as Strongyloides is one of the few parasites which can penetrate unbroken skin.  It could also be Strongyloides fuelleborni, but I’m going to stick to stercoralis.  

As an aside, other parasites which are capable of penetrating unbroken skin include schistosomes, cercariae, and hookworm.  I learned this from Dickson.  Thanks, Dickson!



Iosif writes:

Dear Twip Team,

My differential for this case would be that our young patient has an Ascaris infection. These large worms can live in our GI tracts and have a life cycle similar to Strongyloides, but without a reinfection. Our patient probably had food contaminated with ascaris eggs; from there the eggs would hatch within her GI system and the larvae would then spread via the blood vessels or lymphatics to her lungs where they would climb up the bronchi and then trachea and be swallowed so that they could live their adult lives in the GI system. Judging from her lack of lung symptoms and her short stature as compared to her sister, this infection is most likely a chronic one and she has thus lost a lot of nutrients over time. Thankfully it does not appear that full blown kwashiorkor or marasmus has developed, and without a painful belly I assume that there is no current GI or biliary obstruction. A stool sample could be used to look for eggs. A single dose of albendazole could be used for treatment.

I hope that she had enough catch up growth that she could at least match her sister in height.


Iosif Davidov

PS I had forgotten that you guys asked for audio clips for our differentials so I tried to do one for this case. I was pretty nervous making this so I do apologize for any awkward pauses. If this goes well then I will try to continue using audio files.

Elise writes:

Dear TWIP Trifecta,

I hope this finds all of you well.

Look at me, back in the swing of things (I hope) writing with a diagnosis (although the last one I submitted was late).

I suspect that the little girl Dr. Griffin met in the Dominican Republic is the victim of a substantial infestation of Ascaris lumbricoides. Initially, I thought that she suffered from something a little less dramatic but when I heard the detail of the mother actually seeing a large motile worm in her daughter’s stool, I revised my thinking.

The patient and her family live in conditions that are ideal for contracting this nematode. They are in constant contact with dirt and there is poor sanitation where they live. In addition, children are more likely to become more symptomatic and more adversely impacted by a roundworm infestation because their intestines are so much smaller than those of adults. It is not uncommon for people infected with ascaris lumbricoides to experience very few symptoms unless they are hosting a lot of worms. Younger children are more likely to have symptoms and be negatively impacted by an infestation, most notably by failing to grow properly due to not being able to absorb enough nutrients (as is the case with this child).

There is another possible parasitic suspecting this case: Trichuris trichina, or whipworm. Like ascaris, this is a soil-transmitted parasite, but the symptoms of a Trichuris infection (and since this case has appeared in such a rural area and there is little access to sophisticated testing, the little girl’s symptoms seem to provide the best guide for a diagnosis) involve much more obvious stomach upset: abdominal pain, nausea, bloody diarrhea, sudden weight loss. The patient in this case seems to have much more chronic symptoms most crucially failing to grow and her distended belly, which points more towards ascaris.  

In both cases, the most common treatment appears to be with mebendazole or albendazole, however this patient’s case seems so pronounced that I wonder if she needs some surgical intervention too, to remove the worms that have proliferated so much in her body.  

Thank you so much for your work. I hope all is well.

Elise in lower Manhattan.


Elise writes:

Dear TWIP Trifecta

How are you? I hope to be reporting that I am back from beyond and that I can be a responsible TWIP contributor. It has been a pretty chilly spring in lower Manhattan and all kinds of rain is predicted for the future.

I suspect that the young mother and her son described the case from TWIP 132 have pinworm infections. The symptoms are consistent with the basic pinworm signifiers: itchy anal areas, itch gets worse at night (while the pinworms are laying their eggs). While the woman would like to suggest that her sister’s children are the vector for this infestation, and she may be right because children often share pinworms with one another, her volunteer work with lots of children also provides other opportunities for infection. (Still, her sister’s kids, since they stayed in the home for a while are the most likely suspects. What was the verdict when she asked her sister if her kids had any symptoms?)

Diagnosis can be done in a variety of ways: looking for live worms around the anus and in bedclothes, or using tape around the anus first thing in the morning to collect eggs.

If pinworms are present, the entire house will need to be cleaned and all clothing and bedclothes washed with hot water. Everyone should be treated. Some people have no symptoms even when they have a pinworm infestation and unless everyone is treated, pinworms can come back and run rampant again. Everyone in the household will need to follow the medication protocol at the same time to ensure that the pinworms have been eradicated from all hosts. Getting rid of pinworms is tricky because everyone needs to take the medication and take great care with hygiene.

Thank you so much for all of your work. I have missed being a regular contributor.

Many best wishes,

Elise in lower Manhattan

Scott writes:


There was a bit of confusion expressed in the current TWIP about the candirú, a parasitic catfish of the family Trichomycteridae and native to the Amazon basin, that was discussed at some length.  As a serious freshwater aquarist, I have been aware of this fish since first reading the account of it in Gunther Sterba’s 1966 classic, “Freshwater Fishes of the World,” which includes a drawing of it.

I would recommend a fairly complete and informative article in Wikipedia about the species, Vandellia cirrhosa, the species in the genus most commonly blamed for being a human parasite. It is interesting to say the least, and worth the time it takes to read.  Seems that it’s not as scary as one might believe, considering the Internet legends and general misinformation circulating about it.  But it is an interesting species, with an interesting lifestyle, nevertheless.



Cartago, Costa Rica

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