Case guesses:

Topher writes:

Greeting TWiPsids,

I’m not a professional in any way, just a curious science enthusiast, so I’ll keep my guess general and brief.

1) Rhino should clear up on its own

2) Salmonella could account for most of not all symptoms, antibiotics seemed to clear it up.

3) The three suspects found later, from what I remember, don’t generally cause any problems.

With the exception of maybe Blastocystis. Considering it’s questioned status as a known pathogen, and the relief  of symptoms after antibiotics, I would go ahead and Occam’s razor this bad boy and go with Salmonella being the cause of symptoms.

Ruling out an immunodeficiency disorder, I would imagine I too would be comfortable discharging her. (On follow up I might do another white count.)

I’m not a medical or science professional in any way, so I usually don’t guess, but I thought I’d throw my hat in the ring for the book! (Can’t win if ya don’t play!)



Nicolas writes:

Dear Doctors,

Congratulations for such an amazing podcast. I’ve been hearing it for some years and this is my first time writing to you.

I suspect that this case involves the clever and convenient use of a common treatment to tackle the 3 parasites at once. A fast search on google revealed that indeed metronidazole is an effective drug against this 3 organisms. If these parasites were not described as “rare” I would not suggest any treatment. After all, they are frequently found in stool samples in asymptomatic patients.

My area of expertise in parasitology lies in the medical entomology branch so I can not give a more extense answer. I suspect that there is something else I am missing here, but I hope that this guess is right. and in time for the next episode.


Rio de Janeiro

Connor writes:

Hello doctors mighty,

Firstly loud shout out to all my classmates at Tulane School of Public Health and Tropical Medicine for finishing up medical helminthology last week.

I am still primed to helminth related information, at least I hope so, so my guess may have a bias.

Gut reaction when hearing septicemia by gram negative organism, leukocytosis with eosinophils cleared, must be strongyloidiasis (Strongyloides stercoralis), Rx: Ivermectin and maybe repeat at 2 weeks out. Very good she didn’t get any corticosteroids and didn’t have HTLV-1 (I’m guessing)

SS may not have shown up on O&P because in low concentrations or I am incorrect in my guess.

I wanted to do more of a differential and throw in some neoplasms, other parasites, and maybe even fungi because of the potential for one of those 7th ed. books burning a hole in your pockets. Then I realized I should get back to a Rickettsial Diseases assignment and summarize some medical protozoology lectures.

Hope the my gut didn’t lead me astray.

Dan writes:

Dear TWiP troika

I have been tempted back by the chance to win a signed textbook. Sorry to hear about the loss of the ads – I hope this leads more people to support on Patreon.

This was a nice case. I had to convert “103 degrees” to Celsius but that’s pretty high. The clinical and lab findings point to enteric fever caused by Salmonella enterica serovar Typhi or Paratyphi. Respiratory symptoms are common and the positive test for rhinovirus was falsely reassuring.

Migrants returning to their country of origin are often at higher risk of typhoid fever, being less likely to observe food and water precautions or to receive travel vaccines.

Moving on to the protozoa, Entamoeba coli and Endolimax nana are commensal organisms: passengers not pathogens. Blastocystis – as we know – is ‘mostly harmless’. None require treatment. At the follow-up visit I’d request a stool culture to exclude asymptomatic carriage of typhoid bacteria.  

Best regards


Mike writes:

Hi guys

I’m guessing the woman’s symptoms were due to the salmonella, and the antibiotic took care of that. The results of the O&P showing Entamoeba coli, Endolimax nana, and Blastocystis hominis are generally considered of low or non-pathogenicity in immunocompetent individuals , and since the patient is non-symptomatic I would say she doesn’t need any further treatment.

Mike in Oregon

Chris writes:

Dear TWiPsters

In Athens, GA it’s a rainy 54F (12C), but at least fall has finally arrived. I was thrown off by this case at first, as there’s a lot going on here, but after getting my bearings I think it all makes sense now.

The most relevant finding in this case is probably the Salmonella cultured from the patient’s blood, and typhoid fever can account for all of her symptoms. According to the CDC 5,700 cases occur in the US each year, and a majority of those are acquired while traveling abroad. Her contact with animals in Guatemala may just be one of those red herrings, as there is no animal reservoir for Salmonella Typhi. Instead, it is transmitted by fecal contamination, and is more common in areas with poor sanitation. After being ingested, they can invade the bloodstream and cause fever. Infection is serious, and as many as 20% of cases are fatal.

The three parasites identified in the patient’s stool (Entamoeba coli, Endolimax nana, and Blastocystis hominis) are generally considered nonpathogenic commensals. While symptomatic infection is possible in each case, the symptoms do not align well with what we’d expect, and these protozoans are most likely of little clinical concern.

Even as the patient’s symptoms alleviate, she may still be shedding Salmonella. To ensure treatment was successful, a stool culture was likely performed prior to discharge, and again 2 weeks later in clinic. If both cultures are negative for Salmonella, this is encouraging evidence that she no longer harbors the infection. And as long as the intestinal protozoans are causing no problems, I don’t see treatment being recommended for those.

Yours commensally,


TONI from Spain writes:

Dear friends:

Here is another interesting case and this is my guess.

The presence of Salmonella in the blood is sometimes found in cases of gastroenteritis (about 5%).  Salmonella can also be considered a “sentinel” microorganism for certain diseases. Its presence in the blood could reflect an still-undetected-impairment in the cellular immune response, as it is observed in lymphoma, and HIV infection. Also, salmonella septicaemia may present as a complication in some parasitic diseases. Schistosoma is one such example and Salmonella can remain stuck onto the wall of adult blood flukes.  As a consequence recurrent episodes of salmonella-sepsis can occur. Another case is Strongyloides. Strongyloides is in many ways a fascinating parasite. It is one of a few ones that can complete its life cycle inside its host. This is achieved by an auto-infection route where L3 larvae migrate through the intestinal blood vessels to the lungs and from there climb the respiratory tract and is diluted till it reaches to the intestinal tract again. While migrating Strongyloides can transport bacteria on its tegument or alternatively bacteria can pass through the small ulcers in the mucosa and gain access to the blood stream. As a  consequence many patients with disseminated strongyloidiasis die from bacterial sepsis. As Guatemala is not on the Schistosomiasis-World Health Organization list my top guess would be Strongyloidiasis. Serology is very sensible but in this case could be less specific because cross reactions with other nematodes. Several faecal samples must be requested (until 12 in some cases!) since the number of larvae excreted could be extremely low. By the way, this infection is probably not acute and she must have been infected some time ago, walking barefoot. And the fresh eggs could well have been the source of her salmonella infection. The fever, cough, muscle aches, fatigue and chills could represent an episode of migrating larvae (auto infection cycle).

Thanks again and waiting for the next episode.

P.S. Dr. Despommier, what about the historical heroes? No more episodes? I really liked a lot.


Allan writes:

Drug combination targeting wolbachia.

May really reduce treatment times of Lymphatic filariasis and onchocerciasis:


Allan Robbins, DIH, MPH

University of the Nations

Global Health Training


Kailua-Kona, HI

Peter writes:

Dear TWiP team.

I would like to bring to your attention to an interesting item about African trypanosomiasis, I heard on the BBC Radio 5 Live Science podcast of 5 November 2017. The hosts talk to Dr Annette MacLeod of The University of Glasgow who explains how African trypanosomiasis can exist for years as a largely asymptomatic skin infection with the parasites undetectable by blood smears. Such asymptomatic individuals can act as a human reservoir for the disease, hindering its elimination.

Working with Professor Duncan Graham of the University of Strathclyde, they are developing a handheld noninvasive diagnostic tool able to detect the trypanosomes in the skin using laser Raman spectroscopy.

Link to programme

The item starts at 33:30

The programme details do not provide links to any research papers, I found contact details for Dr Annette MacLeod, should you want to interview her for TWiP:,additionalinformation

At the start of that podcast there is an item relevant to TWiM about how the efficacy of melanoma immunotherapy is influenced by the gut microbiome.

Anthony writes:

Bill Gates on mass drug administration


The village I visited was participating in what’s known as a mass drug administration campaign, which seeks to treat everyone against a disease—even if they are not actually infected or show any symptoms. Typically, of course, the sick are the ones who get treated, not the people who are healthy. But when it comes to combating some diseases, like lymphatic filariasis, it’s critical for health workers to try to treat the entire at-risk population to break the cycle of transmission. If not, the disease could continue to be spread by those who are not aware they are infected.



Vintage photo of portrait of Cyril Garnham

While doing my regular search on Amazon to see if some interesting titles might be available, I came across the listing above.

I do have to wonder what the market is for this item.


Chris writes:

Hello Dr. Racaniello and Dr. Despommier,

My name is Chris I have been studying parasite ecology for the last 4 years at Rutgers and I am currently in the process of interviewing for graduate schools in parasitology. I  started listening to TWIP earlier this year after a professor mentioned TWIV and TWIP during a lecture. I am emailing you to thank you for making such a interesting and educational podcast. I am presently on episode 42 in TWIP and episode 6 in TWIV and I feel like I have truly grown my scientific knowledge in disease ecology.  These two podcasts are just fantastic and are helping to fill a void I have in disease ecology because  the last 4 years I have spent all my time learning fish parasites and had very little time to learn about human ones.  

I think the best quality about these podcasts, besides the interesting stories you tell,  is that you repeat everything. You two always seem to bring up points from past episodes which reinforce the details. I love this due to the fact  that I mainly listen to these podcasts while at work or doing other activities so I occasionally miss a detail, but due to you two repeating everything so much I get the reinforcement I need to retain the information. So please keep on bringing things up from the past.

Onc suggestion I have for the show is that you make a few micro episodes. By this I mean quick episodes where you do a quick review of a small subject or possibly even update on subjects past? Just a few quick episodes that don’t need an hour plus commitment to finish. You guys have been doing these podcasts for almost ten years so there are bound to be some updates you could do a quick review on. Once again I do have a large backlog of episodes so you may have already started doing this, if so please ignore my suggestion.

Please keep it up I love the shows and Dr. Despommier is there any chance I will be able to find you at ASP this year, or the helminthological society of Washington (held at Penn State this year) I would love to say hi in person?

One last thing, I am currently writing this in the truck at my job on my phone so please don’t judge my grammar and spelling so harshly.

Looking forward to catching up on the over 500 episodes I have left.

Warm regards,