Derrick writes:

This is Derrick, glad I got last week’s case study correct with the case of Hematuria. Before diving into the case study, I have a quick question for the panel: how do microparasites avoid infection from viruses or bacteria? Maybe it would be more helpful to narrow the focus on schistosomes. I’m curious because after going over the structure of these parasites, and many others, there doesn’t seem to be any structure dedicated to acting as an ‘immune system’.

With that out of the way on to the case. 

I like to first break down the details to have an idea as to what I should be looking for. To make this a little more challenging I’m going to rely on ‘Color Atlas of Parasitology’ and my own undergrad notes for the most part. The following stands out to me…

Morphology; “Mobile piece of spaghetti,” Tells me we’re looking at a Cestode or Nematode/Acanthocephalans. Eosinophilia supports this assumption.

Target organ, assuming the parasite hasn’t gotten ‘lost’ the target organ is likely the Bile ducts of the liver. Secondary possibilities are the Duodenum/upper regions of the small intestine or stomach. Maybe even the gallbladder, but I haven’t heard of a parasite that targets that region as of yet given that I’m still taking an introductory class.

This pathogen also likely has a terrestrial life cycle. 

Initially, I eliminated Cestodes; most of them target the small intestine and I’m looking more specifically at parasites that target the liver bile ducts, duodenum, or gallbladder. If Nematodes don’t give me anything that specific, we’ll move back to Cestodes. Additionally, the case study does not mention the ingestion of raw/undercooked meats which seems to be the most common way Cestodes infect humans from my understanding.

The most likely culprit in my ‘Color Atlas of Parasitology’ is Capillaria hepatic as the rest seem to target the small intestine/colon, or eventually migrate to the lungs which seems irrelevant to this case. 

First, let’s check the region. A google search of “Capillaria hepatic in Uganda” yields…nothing. This parasite seems to not be endemic anywhere and is rarely found in humans. I looked into the symptoms of this nematode though, and they seem to fit (Hepatitis, fever, eosinophilia). While it seems like a longshot in an epidemiological sense, I’m going to stick with Capillaria hepatic due to the fact the symptoms and life cycle of this parasite seem to fit this case the best.

Google did suggest Ascaris lumbricoides as a likely culprit, though this parasite infecting the bile ducts seems to be the result of it being ‘lost’. Ascariasis does also seem to be much more common. So, Ascariasis is going to be my secondary, honorable mention, and it seems to me that a lot of tests (such as stool samples, and blood tests) would be inconclusive as to the differentiation of the two, and they don’t seem very morphologically different. I’d love to hear how the Twip team can tell these two infections apart. In either case, Albendazole seems to be a good treatment for both parasites.

Håkon  writes:


Håkon (“Hawk- in”)  from balmy Athens GA, currently 77 and sunny here. Having heard last month’s case about the boy in Entebbe- my guess would be ascaris lumbricoides. Given the prevalence of the parasite across Africa along with the “general nutritional deficiencies” mentioned in the last episode, this would be my smoking gun. While doing some research to confirm this theory, I came across a paper talking about the high sensitivity ultrasound gives when confirming a diagnosis of ascaris in the gallbladder- which would explain the “moving spaghetti”. Other ideas I tossed around were an individual from SE Asia who moved to Entebbe with Clonorchis or a nasty case of diphyllobothrium. Ultimately Occam’s razor had me settle on A. lumbricoides. Treatment would be an antihelminthic drug, perhaps Ivermectin, or if necessary a cholecystectomy. Looking forward to your next episode, all the best. 


3-Marcus writes:

Dear Unholy Trinity and Dixon (much like Schistosomes, you are far too delightful to ever be unholy!).

On time again! This time I may ramble on a bit, if you will indulge me. 

Here at 63.5 degrees North, the sun has been peaking out from behind the mountains again. Though I look forward to spring, this also means the sunlight reveals all the dirt we have collected over the winter. This meant I was cleaning the kitchen during my first listen of this month’s case, and was a bit distracted. All I heard was something about right upper quadrant pain and ultrasound, which had me thinking “Pipestem fibrosis? Schistosomiasis again?” (Brilliant plan! «Doing precisely what we have done 18 times before, is exactly the last thing they’ll expect us to do this time»; see Blackadder goes forth But no! There was a wiggly worm there!

In medical school there is an axiom that often proves true – 80-95% of diagnoses can be made on history alone (the exact number varies with the lecturer´s confidence in their own brilliance). So I went back to the start, and listened.

There is a young boy, living on a dirt floor. Now, in the same way that fresh water swimming makes me think Schistosoma, I have a near Pavlovian response to the word “dirt floor” and shout “the unholy trinity” out loud. Not Trichuris or Ancylostoma, no. A visible worm in the gallbladder had me thinking of biliary ascariasis. So let’s unpack that a bit:

Right upper quadrant pain, fevers, and what sounds like jaundice (from Daniel’s evasive answer) – that would be Charcot’s triad for ascending cholangitis. Usually caused by a stone, an obstruction would cause biliary stasis, and secondary to that ascending infection with gut bacteria, biliary colic and jaundice. However – I have never heard of multiple recurring episodes of that (being that it is fatal in 5-10% of cases when treated, and near 100% when untreated).

This being a podcast on parasitism, our patient certainly could have eosinophilic cholecystitis, where ascaris in the gallbladder is a known aetiology, but cholecystitis doesn´t cause biliary obstruction on it´s own. And with jaundice and dilated ducts, there certainly is obstruction here. So what is going on?

Now, the most important step in the treatment of cholangitis is removing the obstruction – usually by ERCP. This allows bile to flow freely out the ampulla vateri; and though we cover with amp+gent+MTZ or pip-tazo, it isn´t unlikely that source control by removing the obstruction may be enough. So I´m thinking, maybe there is some kind of variable obstruction here – either with a ball-valve effect, or something being passed out into the small bowel. This would certainly explain the periodicity, and is the case with ascaris entering ampulla vateri from the duodenum. Since this typically only happens with a very high worm burden (quite probable with his distended belly), it doesn´t seem unlikely that another worm may have made a home in the gallbladder.

As for the eosinophilia – it usually denotes helminth migration and tissue invasion; and is a common finding in biliary ascariasis.

So, there we are – biliary ascariasis. The stool exam may show ascaris eggs, and sputum may show larvae. Treatment with paralytic anthelminthics should allow for normal expulsion; and failing that, surgical or endoscopic approaches may be attempted.

Keep up the great work! I look forward to each episode,


Ps. On a slightly different note – would it be rude of me to ask whether you have considered a podcast of a similar format for more general tropical medicine? It isn’t like you already have too many projects going on!

Leon writes:

Dear TWIPers,

I am writing to you from Grenoble, France, where I am conducting structural research on the unique mechanism of mRNA editing in T. brucei. If you haven’t already heard about this fascinating topic, I highly recommend everyone looking into it. I have been a long-time listener of this podcast, and although this is only my second time writing in, I hope to improve and earn a signed copy of the book!

Now, on to the case at hand. The young boy from Uganda is likely suffering from fascioliasis, which is caused by the parasite Fasciola hepatica. The infection cycle typically begins when water plants contaminated with encysted metacercariae are ingested. Once these little buggers make their way to the small intestine, they hatch and set off on a journey to the liver and bile ducts, causing inflammation, blockage, and dilation of the bile ducts, resulting in abdominal pain, fever, and eosinophilia. The “mobile piece of spaghetti” seen on imaging is likely the adult parasite, which can grow up to 3 cm long and may migrate to the gallbladder. Diagnosis can be made by microscopic identification of eggs in the stool, particularly when adult parasites are present. The treatment of choice is Triclabendazole, administered in two doses of 10 mg/kg given 12 hours apart, in patients of this age.

I hope that the young boy has fully recovered after treatment.

All the best from France,


Ben writes:

My guess is that the patient is suffering from Ascariasis caused by Ascaris lumbricoides. 

The description matches this other case I found by Google searching several of the words from the description. The “right upper quadrant pain” was what convinced me. This other case was in Thailand, but A. lumbricoides is found across the tropics.

-Ben in DC

 (returning book winner)

Eyal writes: (eh-al)

Dear sages or microscopics eucaryotes,

Warm greetings from Sydney Australia, where the temperature is 25c. I’m writing to you on the 3rd of March which is also the 3rd day of Autumn. I guess in Australia the seasons start on the first of the month as we don’t really have different seasons anyway 🙂

First, with regard to last month’s case, boy was I wrong 🙂 Luckily the gentleman had a very competent physician and not an uneducated computer engineer!

Now to the new case: a Ugandan boy less than 10, with recurrent right upper abdominal pain, fevers, eosinophilia, and a mobile large piece of spaghetti in his gallbladder.

I started by trying to understand what intestinal parasites are typical in Ugandan children. luckily I found a PubMed article describing exactly that: Human intestinal parasites in primary school children in Kampala, Uganda by N B Kabatereine et. al. (

Going through the list of typical parasites: Trichuris trichiura (28%), Ascaris lumbricoides (17%) and hookworms (12.9%), as well as, S.mansoni, Strongyloides stercolaris, Taenia sp, Enterobius vermicularis, Giardia lamblia, Entamoeba coli and E. histolytica.

Out of the list described in the article, only 2 species are large enough to be described as a large piece of spaghetti. 

Ascaris lumbricoides – a few millimetres in width and 15-49 centimetres (with an ‘e’ :)) in length. definitely within the spaghetti size range.

Taenia saginata – normally 4-10 meters in length but could grow up to 22 meters. In my mind, it is more within the range of hand-stretched noodles than spaghetti.

with respect to the gallbladder and ducts morphology, I found an analysis of Hepatobiliary and pancreatic ascariasis in an endemic area in Kashmir, India 

( according to that article, ascariasis is responsible for 1/8 of all biliary lithiasis cases.

Based on the symptoms, prevalence and size my guess would be Ascaris lumbricoides.

Treatment, 1-3 days of Albendazole or Mebendazole for him and his close contacts/

For prevention, human feces should be properly treated. 

Best regards,


Mark writes:

Hey TWiPers,

I was chatting about this episode’s case history online at another website. Here is our joint work:

Differential diagnosis

Gallstones: Gallstones can cause similar symptoms as gallbladder ascariasis, including recurrent abdominal pain and fever. However, the presence of eosinophilia would not be expected in this condition, and the ultrasound findings would be different from those seen in gallbladder ascariasis.

Cholecystitis: Inflammation of the gallbladder, called cholecystitis, can also cause right upper abdominal pain and fever. However, eosinophilia would not typically be present, and the ultrasound findings may show thickening of the gallbladder wall rather than a mobile structure.

Hepatitis: Viral hepatitis can cause abdominal pain, fever, and elevated liver enzymes, but typically would not cause eosinophilia or the ultrasound findings seen in this case.

Parasitic infections: Parasites such as ascaris lumbricoides, liver flukes or giardiasis, may also cause similar symptoms. If flukes or Giardia then the ultrasound findings and eosinophilia would be different.

To confirm ascaris lumbricoides as the cause search for eggs in the stool of the sick boy. Their presence would indicate ascaris lumbricoides as the cause.


The description is suggestive of “gallbladder ascariasis” caused by the roundworm Ascaris lumbricoides. This parasite is common in areas with poor sanitation and hygiene practices, and is often transmitted by ingesting contaminated food or water.

In this case, the presence of eosinophilia in the blood, along with the finding of a mobile piece of spaghetti-like structure in the gallbladder on ultrasound, strongly suggest a diagnosis of gallbladder ascariasis. The dilated bile ducts may indicate obstruction caused by the parasite, leading to recurrent abdominal pain and fever.

Treatment for this condition typically involves medication to kill the parasite, such as albendazole or mebendazole, and supportive care to manage symptoms and prevent complications. 

If this diagnosis is correct, then I pass on entering the raffle for a copy of Parasitic Diseases, 7th Edition. My PDF copy is 197MB and is way smaller and lighter than a 602 page hardbound tome. 


Christopher writes:

This is likely a case of an overly adventurous Ascaris lumbricoides worm that decided to go spelunking up the Ampulla of Vater, which is the orifice out of which products of the pancreas and bile duct are dumped into the duodenum. The nematode likely traveled up to the gallbladder with some intestinal hitchhikers, like gram-negative bacteria, which are causing cholecystitis, also known as inflammation of the gallbladder. It could have also caused physical bile duct blockage which predisposed the patient to the infection.

I wonder if similar to strongyloidiasis hyper-infection, an overt gram-negative/anaerobic bacterial infection will override the eosinophilia and cause bandemia instead.



Christopher Hernandez

David Geffen School of Medicine at UCLA, Medical Student 

MPH, Infectious Diseases and Vaccinology 

University of California, Berkeley

Josef writes:

Hello TWiP professors!

It’s a comfortable 70 degrees Fahrenheit with clear skies here in Charleston, South Carolina.

I believe that the young boy with recurrent right upper quadrant pain, fevers, and a “spaghetti”-like abnormality on abdominal ultrasound has gall bladder ascariasis resulting from infection by Ascaris lumbricoides.

When thinking about the gall bladder and potential parasites, my mind immediately went to the liver fluke Clonorchis sinensis. However, this parasite is endemic to Asia rather than Africa, and the adults are shaped more like enlarged orzo than spaghetti. The extra hints of limited living conditions/dirt floors, abdominal distension, and stunted growth led me to conclude that Ascaris lumbricoides is the causative pathogen for the patient’s symptoms. I wouldn’t be surprised if further abdominal ultrasound revealed even more helminths residing in the boy’s small intestine, which are responsible for the distension and stunted growth. A worm migrating from the small intestine through the hepatobiliary tract could have gotten stuck in the patient’s gall bladder and led to the recurrent RUQ pain and fevers. Ascaris infection can also be asymptomatic, which could explain the lack of symptoms among the boy’s multiple siblings.

There are no serologic tests available for Ascaris, however the presence of large, thick-walled eggs in the patient’s stool exam would support this diagnosis. Treatment could consist of albendazole or mebendazole, both of which kill worms by inhibiting microtubule synthesis. Ultimately, surgical removal of the gall bladder may be necessary if the debris from the dead worm blocks the bile duct and leads to cholecystitis. Should the siblings be presumed to have asymptomatic infections and treated as well?

Thank you for all that you do!


– – – – – – – – – – – – – – – – 

Josef Blaszkiewicz

MD/PhD Candidate

Medical University of South Carolina

Kevin writes:

Hello TWiP Team!

It’s a chilly, overcast, but enjoyable 46 degrees Fahrenheit, 8-ish degrees Celsius here in beautiful St. Louis, MO. I recently finished the latest episode of TWiP while walking my dog this afternoon, and decided to write in (finally) after having been a long-time listener. 

With regards to the boy in Entebbe presenting with RU Abdominal pain, fevers, and eosinophilia, my suspicion is that this is a case of Hepatobiliary Ascariasis (HPA) due to parasitic infection by the intestinal helminth Ascaris lumbricoides. The incidence of Ascaris infection is high in rural subtropical/tropical regions where sanitation is limited, which provides further support in this case, in addition to the ultrasound findings and that children tend to present with hepatobiliary symptoms more than adults with Ascaris infection. The “spaghetti” finding also suggests that this boy’s condition is due to a high worm-load and that there has been migration into the hepatobiliary tree, indicating a possible medical emergency.

The ultrasound findings may be sufficient to diagnose HPA, but a stool sample is typically used to confirm the presence of the hardy Ascaris eggs in less severe presentations of infection. I suspect this is what we will see, but one source says that stool examination may have “little diagnostic value in endemic areas” with presentations of HPA. (1)

Albendazole and Mebendazole are sufficient treatments for most cases of Ascaris infection and should be started, but due to the severity of symptoms here, I would suspect that surgical intervention will be required additionally, as this seems to be a case of biliary or intestinal obstruction.

Looking forward to more episodes!





2. Parasitic Diseases, 7th Ed. (2019)

Daniel writes:

Greetings TWiP team from sunny South Africa!

My name is Daniel.

It is a lazy, warm, clear day in Johannesburg.

I am intrigued by the case of the 10 year old boy in Entebbe, Uganda. 

On searching for parasites which can invade the hepatobiliary system and can be visualized by sonography I came across several articles which describe sonographic findings of ascariasis and fascioliasis. 

In an article by Al Absi M, et al, entitled “Biliary ascariasis: the value of ultrasound in the diagnosis and management.”, the authors state that: “The worms are often seen as one or more non-shadowing, tube-like echoic structures, which may be straight or coiled (strip sign). Overlapping coiled or aggregates of worms may have an appearance like spaghetti. Dilatation of the common bile duct with or without a distended gallbladder is the next most common finding”. These sonographic features seem to match the findings in the young boy from Entebbe whose sonar reveals “what looks like a mobile piece of spaghetti in the gallbladder with dilated ducts”.

An article by Richter J et al entitled “Fascioliasis: sonographic abnormalities of the biliary tract and evolution after treatment with triclabendazole.” describes the parasite Fasciola hepaticus as appearing crescent-shaped on sonar. According to this article dilated hepatic ducts can also be present with infection with this organism.

Ascaris lumbricoides and Fasciola hepatica and Fasciola gigantica have a wide distribution, including being found in Africa. Both can cause the recurrent abdominal pain, fever and eosinophilia seen in the patient.

Ova from both organisms can be found on stool microscopy. The ova for Fasciola species may be minimal or absent in acute infections or when there is a low parasite burden. So multiple stool samples may be required. If immunological tests are available these may be valuable in making the diagnosis of Fascioliasis. 

There is also the possibility of coinfection with both Ascaris and Fasciola.

Given that the sonographic findings seem more in keeping with Ascaris lumbricoides, Ascaris infection is my guess.

Thank you all for your entertaining and fascinating podcasts. 

Kind regards


Below are links to the above mentioned articles.

Michelle and Alexander from the First Vienna Parasitology Passion Club write:

Dear Lumbri-Co-hosts,

The case of the young boy with biliary colic is easy to narrow down by considering the visualisation of the parasites within the lumen of the gallbladder. By also taking into account the geography, the dirt floor home and prevalence, we believe we can come to a diagnosis with a good degree of certainty.

While a number of helminths can invade the liver in their life cycle, only a small number can be visualized by ultrasound within the biliary duct:

Clonorchis sinensis and Opisthorchis viverrini: While the adult flukes can sometimes be visualized in the gallbladder, they do not grow much beyond the length of 15mm, resembling Farfalline rather than Spaghetti. Both of these species are not commonly found in Uganda.

Fasciola spp.: While the adults of F. hepatica can grow up to Penne size, the morphology is not consistent with twirlable pasta. While Fasciola spp. are prevalent in cattle in Uganda, a quick search did not yield any report of zoonotic transmission to humans in the country.

Ascaris lumbricoides: This worm is morphologically, though likely not culinarily, similar to Spaghetti. It is also one of the most common helminthic infections in resource limited regions and is often responsible for growth stunting, especially when co-infections with Trichuris or hookworm species are present. As a soil-transmitted helminth, the parasite is acquired by exposure of the bare skin, mostly the feet, to soil contaminated with the larvae. 

Stool examination should reveal the eggs of A. lumbricoides. The sample should also be examined carefully for the presence of other soil-transmitted helminths. Treatment with a single dose of albendazole or ivermectin should be sufficient. The most important steps to prevent re-infection are effective waste disposal and wearing shoes while walking on soil; both require resources often lacking in rural areas.

Thank you for this great case. All the best, 

Michelle and Alexander from the First Vienna Parasitology Passion Club

Martha writes:

Dear TWiPers all

I always enjoy episodes of TWiP and always learn something from researching  the problem. I listen intently to the case presentation for hints. Surely I was not the only person yelling at the screen: “it’s vermicelli !!” when Dr. Despommier asked what sort of spaghetti  was in the gallbladder. 

My research suggests it was not vermicelli. In the USA vermicelli is thinner than ordinary spaghetti at 1.5 mm diameter. In Italy vermicelli is thicker than spaghetti at 2.1-2.3mm diameter. However the adult male Ascaris lumbricoides has a diameter of 2-4mm, so that the pasta most closely resembling it would be bucatini with a diameter of 3mm with a hollow interior similar to the worm’s gut.

Of course the question is not what sort of pasta most resembles the parasite, but what should be done for this patient.

It is known that A. lumbricoides will enter the bile ducts and gallbladder. This is more likely to occur if there is a heavy parasite burden, which is hinted at by the remark that the child’s abdomen is distended. This can result in RUQ pain, acalculous cholecystitis, jaundice and pancreatitis. Although his siblings are without similar complaints, they may well harbor A. lumbricoides as the infection can be relatively asymptomatic.

Treatment depends on how ill this child is. If the child is stable enough then a trial of conservative management could be attempted. This would involve observation while the child is given IV hydration, an anthelmintic agent and kept NPO while awaiting expulsion of the worm from the gallbladder. Should conservative management not succeed, then, if available, attempt ERCP (Endoscopic Retrograde CholangioPancreatography) for extraction of the worm. Cholecystectomy is more invasive but will prevent recurrent episodes. 

Since I suspect other family members are also infected, I would suggest testing and treating them as well.

I look forward to the next episode. 

Best wishes to you all

10-Kimona writes:

Dear TWiP team!

 The tubular shaped pasta product seen in the gallbladder of this young boy on ultrasound could be a case of hepatobiliary ascariasis (HBA). Ascaris lumbricoides is a non-segmented roundworm, belonging to the phylum Nematoda. Eggs are ingested, hatch in the small intestine and the larvae travel in the circulation to the lungs where they ascend the bronchial tree and are again swallowed, usually ending up in the jejunum. Here they mature, find a mate, and females can shed ~200,000 eggs/day – making it likely that eggs were seen on this boy’s stool exam. Large worm burden is more prevalent in children (likely from continuous reinfections) and their sheer bulk can lead to intestinal obstruction. This bulk is also believed to alter gut motility, now locating the worms further proximally in the duodenum, where they have a natural inclination to seek out small orifices. Any type of stressor, such as a simple fever, may trigger migration into one of the ducts/orifices of the biliary tree.

 Treatment of HBA may involve albendazole or mebendazole, the former often used in school deworming programs. Once a worm migrates into a duct such as the common bile duct (CBD), it can cause symptoms of intermittent biliary cholic as it blocks the cystic duct. This boy’s right upper abdominal pain was recurrent, possibly suggesting this. Treatment seems to vary from simply waiting for the worm to exit, giving a vermicidal, or using antibiotics and endoscopy or surgery – especially if there is any sign of acute cholangitis such as this boy’s fever. A few articles referenced concern that vermicidals may kill the worm but then render it stuck within the biliary tree. Gallbladder ascariasis (as in this boy) is less common than bile duct ascariasis and seems often to necessitate cholecystectomy.

 I also found reference to a female:male ratio of 3:1 for hepatobiliary ascariasis, as well as a decreased incidence in children, possibly due to the small caliber of their biliary system. Perhaps this young boy’s presentation is a bit unusual?

 Staring gloomily out the window at over 3 feet of fresh snow! It just doesn’t seem fair…..

“Warm” regards, Kimona

University of Central Lancashire Parasitology Club writes:

Dear Professors

Easter greetings from the University of Central Lancashire Parasitology Club in the wonderful Northwest of Britain.

The weather cannot make its mind up, we have had snow for two days and then sunshine the next day, however in Britain we are used to such strange weather.

We have three soil transmitted helminths in our differential diagnosis.  Ascaris lumbricoides (Roundworm), Trichuris trichiura (Whipworm) and Ancylostoma duodenale (Hookworm) which are a common cause of morbidity in Ugandan children (Ojja et al., 2018)

Trichuris trichiura, the human whipworm, could be a possibility based on the living conditions, and eosinophilia is commonly seen in people with whipworm infection. However, infection is typically associated with chronic and persistent diarrhea which is not in the patient history.

Hookworm infection is­­­­­ predominantly marked by iron deficiency anaemia (Despommier et al, 2019). Both whipworms and hookworms are a quite slender and between 1-3cm in length and may not be visible on ultrasound examination.

We believe that this boy is heavily infected with Ascaris lumbricoides through repeated ingestion of ova via the faecal-oral route due to poor domestic sanitation and likely little access to clean water for washing produce (Ojja et al., 2018). According to Das (2014), larval invasion of blood leads to increase in peripheral eosinophilia and stool examination is often carried out to detect Ascaris eggs.

Ascaris lumbricoides migrates and infests in the biliary tree and gallbladder creating complications such as biliary obstruction (Rujeerapaiboon and Kaewdech, 2021). In biliary fascioliasis and ascariasis, adult worms are visualized in the dilated bile ducts and gallbladder (Lim et al., 2007).

Adult ascarid worms measure between 13-18cm in length (Despommier et al, 2019) and perhaps more likely to resemble spaghetti on ultrasound imaging.

Thank you again for this interesting case about a boy with a spaghetti like structure in his belly and we hope that our letter does not arrive pasta the date to be read on the next show!

David on behalf of:

The Parasitology Club of the University of Central Lancashire.


Das, A. (2014). Hepatic and biliary ascariasis. Journal of Global Infectious Diseases, 6(2), p.65.

Despommier, D.D., Griffin, D.O., Gwadz, R.W., Hotez, P.J., Knirsch, C.A. and Katz, M. (2019). Parasitic diseases. New York: Parasites Without Borders. 

Lim, J.H., Kim, S.Y. and Park, C.M. (2007) Parasitic diseases of the biliary tract, American Journal of Roentgenology, 188(6), pp. 1596–1603. Available at:

Ojja, S., Kisaka, S., Ediau, M. et al. (2018) Prevalence, intensity and factors associated with soil-transmitted helminths infections among preschool-age children in Hoima district, rural western Uganda. BMC Infect Dis 18, 408.

Rujeerapaiboon N, Kaewdech A (2021) Massive biliary ascariasis: an unusual cause of acute cholangitis. BMJ Case Reports CP 2021;14: e239784.

Jason writes:

Greetings TWiP hosts!

It is a cool 7 degrees C in Seattle as I put pen to paper on the TWiP 214 case study. For our Ugandan patient, it would seem that all roads point toward infection with Ascaris lumbricoides, the giant intestinal roundworm. While this nematode usually dwells in the intestinal lumen, it is not unheard of for it to present ectopically in locations such as the gallbladder. The adult stages of this widespread geohelminth are large enough to appear on ultrasound – as they do in this case – and the stunted growth of the child coupled with eosinophilia makes a strong case for a presumptive diagnosis of ascariasis. The next step would be to obtain laboratory confirmation via a stool ova and parasite exam, followed by treatment with albendazole or mebendazole.

Worm regards,