Case guesses:

Mike writes:

Hola amigos,

While Daniel was reading this case I could feel Dickson itching in his seat from all the way across the Country. I hope my senses are correct. Self control is hard. I know. I was in some way wishing this woman’s problem was caused by Mobiluncus because it is such a cool name but I guess I will have to wait for it to appear on TWIM. Now the little voice in my head (we will call him Bill) is screeming “ontological parsimony”. So I’m going with my first instinct of a Trichomonal infection, but the lack of odor is rather puzzling. It’s possible in this world containing vast quantities of feminine hygiene products that this woman has been douching to control the smell. The boyfriend on the other hand may just be symptomless (clueless?). His real problem is quite likely T.gondii of the brain which could explain his obsession with ‘kitty parts’, but more study is required.

p.s. Researching this case led me to a site that said, “Trichomoniasis or a yeast infection can smell like a malt beer.” Yeah, right. There was a time in my life when I probably would have done anything for free beer but not anymore. I now know more about feminine hygiene than I ever could have hoped for, not to mention the YouTube videos that left me scarred for life. Alas.

Mike from Oregon

Tama writes:


Iosif writes:

Dear Twip Troika,

My main guess for this case would be trichomonas vaginallis. This is the most common non-viral STI in the world. Symptoms would mostly match what has been given for the case: burning with urination, redness of the vaginal walls (vaginitis) and discharge. Furthermore, symptoms are rare in males and so the partner could have had the infection and unknowingly passed it onto the patient. The reasons that I am not 100% certain of this diagnosis is that the discharge was described as non-odorous and thick while trichomoniasis usually leads to a thin odorous discharge. I would get a wet-mount slide of the vaginal epithelium to visualize the parasite. Furthermore, Dr. Griffin stated that there may be more than one thing going on so I would guess that she may be coinfected with another bacterium.

Gardnerella vaginalis – Would also give very similar symptoms as trichomonas. A wet-mount can differentiate the two, but both can be treated with metronidazole.

Candida – Would have a thick, white cheesy discharge which doesn’t seem to match our patient.

Gonorrhea/Chlamydia – Put together because these are very commonly co-infected. Gonorrhea does lead to a cloudy/yellow discharge that may be contributing to our patient’s symptoms. A culture or PCR could help with the diagnosis. A combination of azithromycin and ceftriaxone would be given to treat both conditions.

Staph. saprophyticus – Also known as honeymooner’s cystitis. There is no reason to believe that the burning from urination could also be from a UTI independent from a vaginal infection. Especially with the hypersexual nature of her partner. A urinalysis would be needed.

Overall, I believe our patient does have trichomoniasis with a contribution from one of the other infections above. Lab work could be obtained to narrow down the possible culprits and treatment could be started.


Iosif Davidov

Hofstra Nothwwell SOM

Class of 2018

Wink writes:

Dear Professors:

When you are in Manhattan and you hear hoofbeats, don’t think of zebras. I’m going to have to go with Trichomonas. I did find old reports of amebiasis, but there were ulcers of the vaginal mucosa.

Wink Weinberg


Dave writes:

Dear TWiP Trio,

I believe the 22 year old female patient in the Bronx clinic has contracted a case of Trichomonas vaginalis. While her boyfriend is does not show signs or symptoms of disease, tricomoniasis is typically asymptomatic in males but may still cause urethritis and prostatitis.

The woman’s symptoms are typical of trichomoniasis: the frothy, yellow-green discharge is usually smelly, but in this instance the case may be mild and the odor has not had time to totally develop. The redness on the inside of her vaginal walls and discomfort during urination are also textbook symptoms of trichomoniasis.

Treatment includes metronidazole, which has an extremely high rate of infection revolution: according to Workowski and Berman (2010), 95-97% of cases are resolved after 1 dose of metronidazole. However, there is evidence of metronidazole-resistant Trichomonas, so it is advisable that the patient fully complete their treatment course.


David P.

Steven writes:

Good day TWiP triumvirate!

I am a long time listener and even relisten to episodes. I regretted not submitting a guess for the case of Cimex lectulariusa few weeks back, so here is my guess for episode 113.

The patient complaining of vaginal discomfort with a milky discharge seems to be presenting with Trichomonas Vaginalis. A fairly common parasitic infection found in roughly 5% of the population. Diagnosis is simple through a vaginal swab and wet-prep slide, they often present with “clue cells”. I know because I perform them nearly nightly. I work as a medical lab technician while in an Arizona hospital.

I have my associates, nearly a bachelor’s from ASU, already planning on a master’s, but now considering a PhD thanks to your podcast. I am a firm believer that one should never stop learning and your podcast (along with the rest of the TWiX family) resonates that ideal.

Keep up the good work!

Steven Needham, MLT

David writes:

Dear Twipstars,

I had not written in quite a while as I was quite busy – and in more than one instance completely clueless.

For the young lady of twip 113’s case, my guess is trichomoniasis. All symptoms seem to match, including the green yellow color, the discomfort on urination and the itching.   I guess the odor would worsen over time.

The disease seems to be staggeringly common in the US with over 3 million people infected at any time, so that makes it all the more plausible.

Microscope examination or cell culture may reveal the parasite,  and it can then be treated with metronidazole.  I would also recommend taking a HIV test, as I read that trichomoniasis may increase the likelihood of contracting HIV.  I found it a bit worrying that this was not brought up during the podcast, so let’s hope there were no secondary infections.

Kind regards from Nicaragua where after a long and dry time it has started raining and we now have a fresh 31 C,


PS in an attempt for a differential diagnosis I looked up a number of conditions that cause vaginal discharge (e.g. but as this is TWIP, there were no real alternatives.  Furthermore, it seems like the symptoms are typical and specific enough to avoid mistakes.

Elise writes:

Dear TWIP Trifecta

I hope this finds you all well and enjoying the last weeks of summer and about to embark upon some adventures. It is 81 degrees F (27 C) now, but the temperature has been lurching way up lately and there have been lots of thunderstorms that encourage some remarkable humidity.

I have a diagnosis for TWIP 113? Shall I offer my thoughts and then the differential?

I believe the 22 year old woman has become infected with Trichomoniasis, caused by the Trichomonas vaginalis protozoa. This is not an uncommon sexually transmitted disease, and the patient’s symptoms are absolutely consistent with those of Trichomoniasis.  She has some discomfort while urinating, a thick vaginal discharge that is yellowish or greenish and her vaginal walls are red and  irritated.

Having floated this diagnosis, I will say that it would be important to do further testing to confirm my thoughts. Not everyone with Trichomoniasis exhibits symptoms, and the symptoms the young woman has do resemble some other diseases (that are not the result of parasites).

In addition to Trichomoniasis, the patient’s also resemble those of: Chlamydia, Gonorrhea, and possibly even possibly Candidiasis or Bacterial Vaginosis (though the vaginal discharges in these last two diseases don’t classically match those of the patient). The test for Trichomoniasis involves either doing a microscopic examination of the vaginal discharge, by doing a culture from the vaginal discharge (though this can take a number of days), and with a urine test.

Because Trichomoniasis can also make people more susceptible to contracting other sexually transmitted diseases, it is recommended that patients also get tested for gonorrhea, chlamydia, HIV and pelvic inflammatory disease. The disease is most commonly treated with Metronidazole.

Treating Trichomoniasis is not difficult, but the patient’s boyfriend should also be tested for Trichomoniasis since he may have the parasite and be asymptomatic.

I hope she recovered quickly and that her discomfort didn’t last long.

As always, thank you so much for your podcast. I am looking forward to hearing your tales from the end of summer.

All best

Joanne Willey writes:

Hello Daniel, Vincent and Paul,

The case of the 4 year old boy was incredibly tough because the presentation and social history was so nonspecific.  There seemed to be two ways to go about trying to figure this out, but of course we have the distinct advantage that the case was presented on TWIP, not TWIB, TWIF, or TWIV. First, we can assume that without eosinophilia, it’s probably a protozoan.  Because the child had no travel history, one could list common protozoan parasites in the northeast (a pretty short list that starts with waterborne protozoa like Giardia, cryptosporidium, etc – definitely not a fit, but then moves onto Babesia microti – aha!) or you can start with pulmonary edema and not much else, which also led me to Babesia. This protozoan is transmitted by the Ixodes tick, the same tick that transmits the Lyme disease pathogen Borrelia burgdorferi, which is endemic if not epidemic in the northeast, so if I am correct, we can hope the little boy is suffering only from babesiosis, not babesiosis + Lyme. Babesiosis can run the spectrum of  asymptomatic to full blown crisis (like the Indian gentleman with 25% parasitemia you reviewed recently). Babesia infection is especially dangerous in patients who are aspelenic or functionally asplenic (e.g. due to sickle cell disease).

Babesia can be diagnosed by blood smear – one would look for the “maltese cross” merozoites in RBCs.  Treatment for adults is with an antimalarial like atavoquone + a protein synthesis inhibitor like azithromycin or clindamycin. No clue if it is the same for a little kid.

But this brings me to a question for Dickson: both plasmodium and babesia are susceptible (to some degree) to bacterial protein synthesis inhibitors. I have always assumed this is because they target the ribosomes in the apicoplast and mitochondria, but I can find only a few papers that actually test this idea, so I was wondering if Dickson had some greater understanding of this phenomenon that he could share. It is, if nothing else, a great example of the endosymbiotic theory of organelle origin.

Thanks for the great podcasts – my soon-to-be second year students at Hofstra Northwell SOM will be listening all summer long (at least they better be).

Best wishes,

Jo  (Iosef’s former ID prof, so I really hope i got this right or my credibility is shot)

Steve writes:

Hi Vincent, Dickson, and Daniel,

Thought you might find this recent case study on movement North (and hybridisation) of schistosomes toward Europe.

I don’t think we have to worry about wild swimming too much in the UK yet though!

Incidentally: I think I inadvertently solved‎ the current TWiP case in listening to Dickson picking an early House episode to pieces in one of your early tapeworm podcasts. I won’t count that as a personal score though. 🙂

Would be interested to hear more of parasitism beyond the field of human diseases too. I think that Dickson does have the natural history and ecological experience to branch out more, and bringing in the recent penguin case was a good idea, but the insect and plant world has its important parasitic relationships too.   Mind you, going back over the podcasts, I get the impression that we have barely scratched the surface on the human parasites, however long the episode!

Many thanks,




Anthony writes:


hey found that eggs from four species of parasitic worm (helminths) were present: roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), tapeworm (Taenia sp.), and Chinese liver fluke (Clonorchis sinensis).

Chinese liver fluke is a parasitic flatworm that causes abdominal pain, diarrhoea, jaundice and liver cancer. It requires well-watered, marshy areas to complete its life cycle. Xuanquanzhi relay station was located at the eastern end of the arid Tamrin Basin, an area that contains the fearsome Taklamakan Desert. The liver fluke could not have been endemic in this dry region.

In fact, based on the current prevalence of the Chinese liver fluke, its closest endemic area to the latrine’s location in Dunhuang is around 1,500km away, and the species is most common in Guandong Province – some 2,000km from Dunhuang.

Researchers from the University of Cambridge’s Department of Archaeology and Anthropology, who conducted the study, suggest that the traveller infected with this liver fluke must have journeyed an enormous distance, and suggest the discovery provides the first reliable evidence for long distance travel with an infectious disease along the Silk Road.

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