Christopher writes:

Good afternoon Twip team! 

My thought for this case is schistosomiasis infection. Sometime somewhere, our 36-year-old male patient took a dip in the shallow waters of a river or lake filled with snail hosts. The schistosomes released countless ova into his circulatory system, where some lodged in the small capillaries of the lungs, eyes, skin, and bowel. As the immune system tried to wall the eggs off, neighboring organs suffered from the collateral damage. In his case, the pulmonary vasculature was injured, leading to shortness of breath either through pulmonary hypertension or heart failure. There are no other clear signs of heart failure seen on physical exam or X-ray, but I’m wondering if his abdominal pain may be caused by congestion secondary to heart failure. The conjunctivitis, stinging pain, and abdominal cramps with bowel irregularities could also be caused by damage done by the immune system’s response to the eggs lodged in these tissues. 

The timing of these findings makes me hesitate. Unless he lives in a place where schistosomes are endemic, he might have had this infection for at least 5 years. How are multiple organ systems being simultaneously affected now and not gradually over the course of years? It is possible we aren’t finding any ova or signs of infection because the sensitivities of O&P and serologies aren’t 100%. Maybe the adult schistosomes have been dead for a while so we won’t find evidence because of a waning antibody response or cessation of egg production. 

As always, I am left pleasantly puzzled. 



Christopher Hernandez

David Geffen School of Medicine at UCLA, Medical Student 

MPH, Infectious Diseases and Vaccinology 

University of California, Berkeley

Eyal writes:

Dear Vincent and the sages of the microscopic eukaryotes.

Greetings from Sydney and the land down under where the temperature is a nice 20c as is proper for the first week of spring 🙂

For the case study this week I will have to go only by the written description of the case. As was sent in by Michelle and Alexander. Unfortunately, the sound for the podcast was cut off at exactly 1 hour and 15 minutes. So can’t use Dr. Griffin’s tone and innuendos to help my guess.

Unfortunately (for me not for the patient), the initial lab results were grossly unremarkable and a chest X-ray showed no abnormalities. Also as noted the patient’s own stool examination had no interesting results.

Based on this lack of lab results I’ve decided to try and match common Caribbean parasite disease symptoms with the patient’s reported symptoms of shortness of breath, stinging pain in different parts of his extremities, fatigue, abdominal cramps and bowel irregularities.

I’ve ruled out Schistosomiasis as fever and rash are typical symptoms but are not presented by the patient.

Lymphatic filariasis was ruled out as there is no swelling

Whipworm was ruled out as I would expect this to show in the stool examination and would not cause pain in the extremities

Paragonimiasis caused by the lung fluke was ruled out as there was no fever or hives

 Chagas disease was ruled out as the timeline is too short for major neurological damage and there are no signs of heart problems

The only disease I could find that matched the symptoms to some extent was Ascariasis. The pain in the extremities might have been caused by some duct blockage? i have no idea…

So my guess for this week is Ascaris and could be treated with albendazole/mebendazole.

On a different note. in the last week there has been an interesting case of Larva Migrans Caused by Ophidascaris robertsi Ascarid found in an Australian woman’s brain. First documented case of the Carpet Python parasite in humans.

I was wondering if you could review the case study in the coming episodes.

ANU article: 

CDC article: 

Many thanks for all that you do.


James writes:

This is an interesting one!  36 year old with a bunch of nonspecific symptoms, suspects parasite (it IS twip after all) and somewhat remote travel to Caribbean and Africa. We don’t know the patient’s home country for sure; Germany or Austria from the Vienna Passion Club?

What’s true and what’s a Red Herring in this case? Is it a tropical parasite, or is it a locally acquired one?

Stinging pain in extremities makes me wonder about B12 deficiency which CAN be related to Diphyllobothrium, also would give fatigue, confusion/depression. Also can have vision problems. He could get that tapeworm almost anywhere. I might expect the stool O and P to be positive but don’t really know the sensitivity/specificity. Labs might be expected to show a macrocytic anemia with B12 deficiency.

Let’s see…how many dozen parasites can cause bowel irregularities and abdominal cramps…ameba, Giardia, worms…long list.

Eye irritation of course brings to mind Onchocerca, but sometimes also Loa loa.

Guess I’ll go with the tapeworm and B12 deficiency…got to get back to my intro to Micro lectures!

James M. Small, MD, PhD, FCAP

Professor of Pathology and Microbiology

Director of Clinical Career Advising

Rocky Vista University

Rafid writes:


Unfortunately I had trouble downloading the last 20 minutes of the last episode so I hope that I am presenting the right case.

As a clinician, if I would have seen this patient in the emergency room with bowel irregularities,  shooting pains in his limbs and who has a list of things that they want tested my first thought would be a functional syndrome such as irritable bowel syndrome with fibromyalgia which would be the most likely diagnosis. Luckily your podcast forces me to think a little deeper. The first parasite syndrome that I think of that links dyspnea, a change in bowel habits and peripheral neurological symptoms is chronic Chagas. I’m not sure what to make of the ocular symptoms but I did find some case reports of uveitis in chronic Chagas. I would start my investigations with an echocardiogram to see if there is any evidence of cardiac involvement and I would do some stool tests for blood, fecal calprotectin to rule out inflammatory bowel disease. If the cardiac echo shows LV dysfunction i would test for Chagas. There seem to be many ELISA tests out there so I curious to know which ones the TWIP experts would choose.  

I would like to make another shout out to Michael Libman in the tropical disease department at McGill. I would highly recommend for a teaching award.

Thank you for your great work.


Reem writes:

Dear TWIPers,

Hi! My name is Reem, I am currently a sophomore in high school. I first heard of Dickson Despommier when I encountered his book (people parasites and plowshares) when organizing a huge stack of books at the Columbia university press. As payment, I was allowed to take that book (along with many others centering on biology) home! After reading the first chapter I became obsessed with parasites, only to later discover that my mum has been working with Dickson to publish his most recent book! Shortly after, I discovered the podcast and have been listening avidly since then. Sadly I’m only about 20 episodes in since the episodes are so long and I also have to focus on school. Anyway I just wanted to say thanks for making the podcasts! Also, does anyone have advice for how to get volunteering opportunities at labs? Ive tried to reach out to multiple labs hoping for opportunities, but it’s hard to be taken seriously as a 15 year old.



Paul writes:

My top guess: Toxocariasis. 


1. Unilateral eye disease

2. A parasite with worldwide distribution seems more likely given short and remote travel history. 

Paul Blanchard MD

Martha writes:

Dear TWiPers 

Again I am probably responding too late to episode 220. 

If we had been able to ask questions I would have liked to ask why the patient thought that his problem was parasitic. Has he been treated for a parasitic infection in the past or perhaps failed to take a prescribed treatment?

Nevertheless, I will jump in with a guess. He had traveled to areas where he might have acquired an interesting parasite 4-10 years ago. The life span of Wuchereria bancrofti is said to be 5-8 years. While alive the worms interfere with the hosts’ immune response. The dead and dying worms no longer exert this effect on the host resulting in an inflammatory immune response. I can imagine that the patient’s symptoms are due to this. 

I’m keeping this short. Best wishes to all.


P.S. I have already won and received a book, thanks. However I still enjoy doing the puzzle.

The University of Central Lancashire Parasitology Club writes:

Dear TWIP Professors, 

Greeting from the University of Central Lancashire Parasitology Club. 

We have been extremely busy with exams and the successful graduation for some of our group and we are now starting our 2023-24 academic year with excitement and vigour for the challenge of this new case.  

Our candidate list for case included schistosomiasis, mansonellosis and babesiosis. 

The general fatigue suggests a systemic involvement, but our interest was piqued by the involvement of the eye and the travel history to Africa and the Caribbean suggesting filariasis.  

Mansonella ozzardi is a filarial parasite transmitted by biting midges in South America, the Carribean and Central and West Africa. Infections may be asymptomatic, but case reports indicate that fatigue, respiratory symptoms, joint pains, vague abdominal symptoms. Eye involvement can lead to swelling, sometimes referred to a Ugandan or Kampala eye and this is perhaps why the patient suggested his own parasitic diagnosis.  

It would be quite funny if he wrote in to answer the case on TWIP! 

Diagnosis relies on detecting the parasites in peripheral blood or skin snips (Ta-Tang

et al., 2018) which might explain the negative finding on serology and faecal examination.  

Treatment with ivermectin appears to be effective and it is fascinating that effective treatment of mansonellosis might include doxycycline to kill the endosymbiont Wolbachia   

We pin our hopes on Mansonella and as always, we are grateful for the challenging case and the opportunity for learning 

We eagerly await the arrival of Parasitic Diseases volume 7 and will send a photo of the group when the books arrive. 

 All the Best  

Neal Vickers and Nilgun Poyraz  

Of behalf of The University of Central Lancashire Parasitology Club