Case guesses

Mike writes:

Hi guys

I’m going to go out on a very long limb and guess this woman has Cryptosporidiosis from drinking contaminated water (cats?) leading to diarrhea, and the worms in her stool are from fruit fly larvae in the mango.

Mike in Oregon

Neeraj writes:

Hello twipanorama,

This is Neeraj from murky and rainy South San Francisco in CA. I am mailing to make a guess for lady in the case for Twip 122. Based on Dr Griffin’s reported observations, I predict the lady has a pinworm infection. This can possibly be a result of poor hygiene in her place of residence with the local people. The best way to confirm the infection would be to either look for the worms in the perianal region 2-3 hours after the person is asleep (I can imagine it would be hard to be asleep when some ID doc is scratching your posterior outlet J). A better way to diagnose, would be to do the tape test where in the perianal skin is touched with a transparent tape to collect possible pinworm eggs around the anus. If a person is infected, the eggs on the tape will be visible under a microscope. Once confirmed, the patient can be treated with mebendazole, pyrantel pamoate, or albendazole.

Btw, thanks for reading my mail in relation to the last TwiP. It was nice to hear your thoughts, especially on the malaria treatment regimen that was presented in the Science paper. Dr Racaniello, I just wanted to update you that the study in the published paper wasn’t the work of sutrovax, the company I currently work with. So unfortunately, I won’t be able to tell you the details on any phase I trial that ever gets done with this slow releasing medication. But it is certainly something interesting with respect to how people think about dealing with and controlling the spread of malaria, which is a huge societal burden. And especially the lack of good medications / vaccines for prevention, compounds the issue even more. Too many young kids in economically weak regions (especially in the sub-saharan African region), die due to lack of better preventative treatments. Talking about which, what are your thoughts about the initiatives to make transmission blocking vaccines (please see attached pdf for reference)? I think it could have a huge impact on the overall control of malaria, but then again I just might be naïve in assuming that these things can work as well as they are postulated to be. But all said, it is something I have become increasingly interested in and feel that something significant can be achieved with the present state of the art research facilities. We should certainly be able to do better than the most recently approved RTS,S vaccine ( for the treatment of the same. The efficacy for this approved treatment is just far from ideal and unfortunately this is the best we have at our disposal at the moment.

Anyhow, enough on Malaria but before I wrap, I would like to respond to Dr Despommier’s query about when was I at the Rockefeller University (as I had mentioned in my previous mail). I was there from 2004-10. 6 wonderful years in the most amazing city there is on planet earth. I don’t think people who haven’t lived in Manhattan, can ever realize, how much stuff happens there through every ticking second. It’s truly a city that never sleeps and that did help me quite a bit in my graduate life. Late night lab shifts were never a problem, especially with still seeing people around. I believe Rockefeller University has awesome student housing and it even has a bridge which connects the residential building (called scholar’s), directly to the university. Dr Racaniello, where were you staying when you were a postdoc there? I am assuming the pricing was a lot more subsidized back then, than it is now.

Finally, it’s always great to gain more knowledge through the TwiX series of podcasts and I can’t imagine a better use of my time, than listening to one of those (especially on the painfully slow commute to my home where in, a 10 mile drive takes an average of 45-60 mins).  I hope there will be a few more episodes before Christmas.



P.S: Driving to work, I saw the symbol for the gas station Valero (please see attached image) and the nerd in me reacted by thinking that the swiggly creature wrapped around the “V”, looks like Ascaris (that’s how badly vested I am with parasitology nowJ)

Neeraj Kapoor, Ph.D.

Scientist, SutroVax

South San Francisco

Shelby writes:

Hello Twipsters,

Greetings from Nashville where it’s a rainy 12°C.

It sounds like the young American mango eater of Dutch descent has hookworms, possibly Necator americanus. The papain or lupeol in the mango could have acted as a stressor to the helminths causing them to abandon ship via diarrhea. Treatment, a course of ivermectin and some comfortable shoes to hopefully reduce the risk of reinfection from fecal contaminated soil.

Thank you,



Dr Griffin, could you explain your pronunciation of centimeter. After googling “sonometer” I found that it was a preferred pronunciation of centimeter amongst some health care professionals but aside from that couldn’t find a more detailed answer.

David writes:

Dear TWiP Doctors,

I believe that this aid worker has contracted Dipylidium caninum from the kittens (or rather, the fleas on those kittens) she played with a month earlier. According to the 6th Edition of Parasitic Diseases (!!), within 25 days of ingestion of an infected flea, the worm begins to release gravid proglottids into the lumen of the intestine, where they can exit the body along with the feces. This fits the time frame between when she potentially contracted the worm and when she finally begins to shed the proglottids in her stool. D. caninum also causes the symptoms the young woman faced: abdominal discomfort and diarrhea. This worm is most prevalent in children younger than 8, however given that she was playing with kittens in an environment that favors growth and development of pathogens, the chances for her infection are much more likely.

The rainwater-washed mango may have been a red herring for these worms – however it is possible another pathogen helped to exacerbate the woman’s diarrheal symptoms, allowing her to more clearly see the worms. At first, I thought these could be pinworms or another worm contracted from the mango, but shedding worms/proglottids within a day of infection did not make sense. It is possible she might be harboring another pathogen (toxic E. coli perhaps?). I found an interesting article on traveler’s diarrhea spread through mangoes:  When The Mango Bites Back.

As always, thank you for the informative and entertaining podcasts. I will give the podcast and its hosts (no pun intended) a shoutout during my next Journal Club presentation.


David P.

Toni writes:

Dear “parasitophorous” doctors:

I am a long-time fan of TWIM, TWIV and of course, TWIP.

First of all, sorry for my english, I am a spanish clinical microbiologist and english is not my first language.

In relation to the TWIP 122 case study, there are several options.

  1. Because usually helminths have a first period within the human host when they are not readily detected, known as pre-patent period, I think the recent history facts have nothing to do with the moving parasite encountered in the faeces. I mean, the adquisition of the parasite must have occured some time before, probable weeks, months or even years before and has nothing to do with the mango consumption of the rainy weather.
  1. A moving-worm-like-parasite 1cm in lenght strongly sugest me Taenia spp. As Taenia solium sheds not-moving-proglotids and Taenia saginata does moving ones I would think of this later species. Taenia saginata need to shed motile proglotids, since its intermedium host, cows, are not coprophagus animals, so the proglotids need to, somehow, look for its next host. On the other hand pigs are “faeces-lovers” so, Taenia solium doesn´t need to shed motile proglotids since the intermedium host, that is, pigs, will go for “faeces hunting”. Said that, the clinical picture doesn´t fit very well with Taenia spp. infection, where diarrea is not a usual presentation. It usually causes very few syntoms if any, and usually is detected when motile proglotids are expelled withing the faeces. The proglotids are quite “squared”, whitish and around 1cm wide and long. The are not worm-like-shaped.
  1. A motile 1cm-long worm-like parasite also reminds me of Enterovius vermicularis. Adult females usually deposit the eggs around anus at nighttime or during the “siesta” or nap. But again, the clinical picture doesn´t fit exactly with the usual one. As eggs are usually not detected in the faces we need to perform a specific test, the Graham Test. From time to time you can even catch the adult female as she is in her “perianal tryp” and I even once was lucky enough to see an adult female stuck to the scotch tape. But again, diarrea is not a frequent syntom, but doesn´t rule out.
  1. Lastly. The worms encountered in the faeces could be of non-human-origin. It is not unusual for a laboratory workers to receive specimens of such type. There are worms everywhere, really everywhere. It is not unusual to earth worms to be found around or even inside faeces when theses are deposited outdoors, but this is not to say that those worms are from human origin. When a patient comes to my laboratoty bringing a worm the first question I always ask is: have you really witnessed the parasite going out with the faeces?. If it was the cae in our case study other more frequent causes could be assigned as a cause of an acute diarrhea: virus and bacterias or even protozoal parasites.

P.S.  I really enjoyed the Dr Despommier book “People, Parasites, and Plowshares: Learning From Our Body’s Most Terrifying Invaders” and as sugested in this book, the other equally fantastic book from Robert Desowtz “New Guinea Tapeworms and Jewish Grandmothers: Tales of Parasites and People”.

Finally can I do a suggestion for future episodes?. I suggest you could treat the very interesting theme of Hygiene hypothesis, the relationship between parasites and autoimmune disordes and the medical use of parasites for autoimmune and other inflamatory diseases.

Congratulations for your excellent program and keep on doing it!!

Bjorn writes:


I’ll venture a diagnosis on the 23 year old female  aid worker in the DR. The relevant facts of this case  seems to be:

  *  She’s got diarrhea.

  *  She’s eaten a mango washed in water of dubious provenance.

  *  She’s eaten many kinds of food, been in contact with many species of animals including cats, dogs and chicken.

  *  She’s not taken many precautions against possible infections.

  *  She’s observed some larvae-like, motile things in her diarrhea.

      –  The toilet she observes this is is not one she’s using every day, since she’s out travelling to a border town.

So from this, it’s actually very difficult to come up with a certain diagnosis, here is a number of plausible explanations that all end up explaining the observable signs:

*   The larvae-like things in her stool should of course be examined, but my guess is that  they are insect larvae of some kind that  originated in the toilet, not her intestines, and only got mixed with her stool when she defecated.  Also, nothing she ate the day before would have had time to develop this far in just a day or so.

*  From the story as it was told  I would be suspicious of the water used to wash the mango:  That water could have been contaminated with bird poop, rat poop, mouse poop, bat poop, cat poop, dog poop, human poop and lots of other things that could make you sick.  Nothing definitive here however.

*  The diarrhea could be caused by a really long list of agents,  but bacterial or viral gastroenteritis would both  be high on my list of differentials. Norovirus, rotavirus, salmonella would be three, but I’m sure there are plenty more.   If the water used to wash the mango was the source of the infection, then some  bacterial/viral  infections could have had time to develop into disease even if it’s only a few hours since exposure.

* Her contact with chicken would also represent a risk for salmonella, so that is a possibility.

* Malaria.  Can cause diarrhea, and there is certainly malaria in DR. She doesn’t report chills or fever, but that doesn’t mean she doesn’t have it.  Does she take malaria medication?

* Cats and dogs => hookworm

* However, since this is TWIP we also have to include (at least) giardia,  cryptosporidiu  and entamoeba histolytica in our list of differentials.  Again, ample possible sources of possible infection in  her lifestyle.   She doesn’t report foul smell from her stool so giardia therefore isn’t high on the list, crypto certainly is possible.   Entamoeba histolytica tend to produce bloody stool (dysentery), but perhaps only diarrhea the first day before it’s had time to fully develop?

*  … & so on.    There are just too many candidates  to list  here, and none seem to be much more obvious than any others.  🙂


    *  Temperature (fever)/CRP, antibody tests etc. to confirm/rule out viral/bacterial gastroenteritis?  Perhaps PCR of stool?

    *  PCR/microscopy of stool to look for giardia/crypto,  helminths, entamoeba histolytica.

    *  Malaria antibody test/blood smear.

    *  Microscopy/magnifying glass, tweezers,  scalpel  and a good text on entomology to  identify (or not) the larvae-like entities.

Hopefully she recovered in one way or another, and in addition got some instructions on how to perhaps have somewhat lower risk profile for infections, and perhaps even some deworming medication, just in case 🙂

My guess on the theme Dr. Griffin was alluding to:   Perhaps “this is really hard because we don’t know enough and what we know is confusing”.  I would guess that is a rather common situation in the field.

I Love your podcasts.  I’m a telecom/computer engineer that has been listening to TWIx  since I took Vincent’s virology course on coursera in 2013, which I did for no other reason than Vincent being very enthusiastic in his lectures 🙂  You guys are an inspiration.

Best wishes


Tamera writes:

I need help with figuring out all of my true infestations.  I have been sick for several yrs. I recently was diagnosed with this strongyloides or a cross over other type of worm. I see them in my eyes. I’m not sure I had a treatment for a different mite problem. Now the Dr that found the serology positive doesn’t want to test anymore. Yet I’ve had pneumonia countless times. I was given steroids. My thyroid has a nodule and so does my vocal chords. I need to know where I can go that actually has experience. Thank u.


Vic writes:

Dear TWiP Team,

In TWiP 122, you received a listener email which described a new drug delivery system which was being tested in pigs.  This was a capsule which expanded in the pig’s stomach and allowed drugs contained in the casing of the capsule to be slowly delivered through the digestive system. You all seemed slightly sceptical that this would work.  The story that follows bears out your scepticism.

In the early 1970’s my dad owned several livestock markets in Nebraska.  As a result, we often had hundreds of feeder calves (feeder calves are calves that have been weaned from their mothers and usually weigh between 500 and 600 pounds) that we had to feed for a few days between sales. Feeding those calves was a very expensive proposition, and my dad was always looking for ways to economise on his grain and hay expenditures.

My uncle David was a veterinarian who had left private practice and gone to work for the Eli Lilly pharmaceutical company in the early 1960’s.  By the early ’70’s he was in charge of the Agricultural Division of Eli Lilly.  Uncle Dave had lots of ideas.  One of those ideas was that hay, which, although it has some nutritional value, was much more important as a digestive stimulant. This is because in the largest of the animal’s stomachs, the rumen, hay scratches the walls of the stomach, which aids and improves some of the digestive processes.  Additionally, hay helps to abrade grains which are then more efficiently absorbed.  The problem is that the hay also gets digested and is passed out of the system and then needs to be replaced.  So…if instead of scratchy hay, you could use a scratchy plastic that would remain undigested in the rumen, you could potentially eliminate the need to constantly replace that expensive hay.  Who knows?  It might work.

Consequently, Uncle Dave had his lab create plastic boluses, which were about the size of a charcoal brickett.  You could shoot these down the throat of a calf with a bolus gun.  The boluses would enter the rumen where they would pop open and become about the size of a softball, a softball with a very spiny, scratchy surface.  Because they were plastic, they were supposed to float in the liquid of the rumen, scratching the walls and abrading the grain, and because they were the size of a softball, they would not be able to pass through the rest of the calf’s complicated digestive system.  No need for hay…problem solved, money saved, everybody happy!

Well, we ran 75 calves through the chute and gave each of them about ten of the magic boluses. No one was really sure how many we should use, but ten seemed like a good number to start with.  This was not the first time we had worked with Uncle Dave to test materials and methods, so we were used to a fairly ad hoc system of testing.  More about that in another email that I will someday get around to writing to you guys at the Urban Agriculture podcast concerning how American agriculture became what it has become…but I digress.

Each calf got 10 boluses.  We fed them their daily grain ration, and went home.  We assumed that it would take a day, or two, for the magic to begin to work, but confidence was high that we had entered a brave, new, hay-free, world.

The next morning we all gathered at my dad’s “Republican Valley Livestock Market” in Franklin, Nebraska to check on our 75 calves.  We were pretty sure that they would be happily munching their corn and oats and not missing hay at all.  They were, indeed, happily munching their corn and oats while standing in hundreds of piles of what appeared to be huge, black, spiny, plastic, softball sized, spiders.  We didn’t count them, but it seemed a fair bet that there were around 750 on the ground.

I guess Uncle Dave, as a scientist and researcher, was used to unexpected results.  He just shrugged, and probably was already thinking of another problem to be solved.  We, on the other hand, were pretty shocked.  I, as a teenager who was regularly tasked with cleaning out the pens at the market, was dismayed to realise that I was going to be the one who had to deal with this spiny plastic mess.  The calves did not seem to mind at all.  They were just looking forward to getting their trough filled with hay.

I certainly wish the folks that are testing the palm sized gizmos that will slowly deliver drugs to those pigs the very best of luck.  I do, however, feel sorry for the kid who is going to be scooping out the pig barn.

Med Venlig Hilsen,


P.S.  I am the Ship’s Agent from Kristiansand, Norway who has written to you a couple of times on TWiV.  Sorry to sandbag you a bit, but I have lived in Europe for 25 years, 16 of them here in Norway.

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