Eyal (no relation) writes:

Dear Twip Professors.

Happy new year from the land down under where the weather is hot and the vacation is over.

First I would like to say that episode 227 was fascinating.

Indeed Alpha Gal syndrome (colloquially called red meat allergy here) is a very big problem here in Australia and not only in the US (especially when red meat is more of a religion than a diet here in Australia). Basically due to the very outdoorsy mentality here in Australia, half of the people are at risk of developing Mammalian Meat Allergy (MMA). It’s bad enough that kids are taught to never pull out a tick but instead to either freeze them off or to use an anti tick cream.

Well at least ticks don’t hurt you as quickly as salt water crocs, or the blue ring octopus, or the cone shaped snail, or the brown snake or the taipan, or the shaks, or mostly everything on this continent…


‘ The Australian paralysis tick (Ixodes holocyclus) is responsible for over 95% of tick bites in people in eastern Australia and for most tick-borne illnesses in Australia. The Australian paralysis tick is capable of causing severe allergic reactions, including tick anaphylaxis and MMA. The Australian paralysis tick is commonly found on the east coast of Australia which means that over 50% of the Australian population are potentially exposed to this tick.’

For the case of the 20 year old Israeli female, I will go out on a limb and say Amoebiasis.

For a differential I looked at all parasites I could find that are typical for south east asia and looked for those that would cause abdominal pain (almost all), headaches and fever (most of them) and would show up in liver CT. Here is a quick summary of my assessment:

  • Hookworm
    • Common Symptoms: Itching and a localized rash at the site of skin penetration, cough, chest pain, abdominal pain, diarrhea, and anemia.
    • Can cause abdominal pain but does not reproduce in the liver. No anemia, no itching
  • Giardia
    • Common Symptoms: Diarrhea, gas, stomach cramps, nausea, and dehydration.
    • Symptoms don’t match, no pet contact.
  • Strongyloides
    • Common Symptoms: Skin rash, abdominal pain, diarrhea, and cough.
    • Causes abdominal pain but does not reproduce in the liver. no report of rash or cough
  • Hymenolepis nana (Dwarf Tapeworm)
    • Common Symptoms: Often asymptomatic, but can include abdominal pain, diarrhea, and loss of appetite.
    • didn’t eat raw meat or eggs
  • Trichinellosis.
    • Common Symptoms: Diarrhea, abdominal pain, muscle pain, fever, swelling of the face.
    • Specifics: Causes abdominal pain, does not reproduce in the liver. No uncooked meat consumption, no swelling of the face
  • Capillariasis
    • Common Symptoms: Abdominal pain, diarrhea, weight loss, malabsorption.
    • no weight loss or malabsorption.
  • Angiostrongyliasis
    • Common Symptoms: Severe headache, stiff neck, tingling or painful feelings in the skin, low-grade fever.
    • could be contracted from eating contaminated vegetables but no report of stiff neck, tingling or painful feelings in the skin
  • Ascaris (Roundworm)
    • Common Symptoms: Abdominal pain, loss of appetite, weight loss, cough.
    • no report of weight loss of cough.
  • Trichuris (Whipworm)
    • Common Symptoms: Diarrhea, abdominal pain, rectal prolapse in severe cases.
    • fever is not a symptom, I wouldn’t think would cause eosinophilia.
  • Enterobius (Pinworm)
    • Common Symptoms: Itching around the anus, disturbed sleep, irritability.
    • Symptoms don’t match at all.
  • Cryptosporidium
    • Common Symptoms: Watery diarrhea, stomach cramps or pain, fever, nausea.
    • Symptoms are very close but I didn’t think it would show in the liver.
  • Entamoeba
    • Infection Method: Ingesting cysts from contaminated food or water (pools and sea, the cysts are not killed by chlorine).
    • Common Symptoms: Diarrhea, abdominal pain, liver abscess (here we go).
    • Causes abdominal pain and can form abscesses in the liver
  • Blastocystis
    • Infection Method: Ingesting cysts from contaminated water or food.
    • Common Symptoms: Often asymptomatic, but can include abdominal pain, diarrhea, bloating.
    • no mention of bloating and wouldn’t cause liver abscesses.

Based on the above assessment the best fit is Entamoeba.

As always, eagerly waiting for the Twip.


Sara writes:

Hello TWIP team, 

Writing to you from snowy Philadelphia. I am a recent ID fellow/new ID faculty, and relatively recent listener. Wish I knew about TWIP during fellowship! Here goes my first guess at a case. 

For the returning traveler from southeast Asia with fever, liver lesions and eosinophilia 10 weeks after travel, a few things came to mind for the differential.  

First, I considered amebic liver abscess caused by Entamoeba histolytica. The incubation period would be correct, but a few things don’t fit. Primarily, I believe this is less often associated with eosinophilia and some of the imaging findings were not consistent.

Second, I considered liver flukes. She was traveling in areas where Clonorchis and Opisthorchis are endemic, and the clinical scenario could potentially fit with these. However, it was stated that she didn’t eat any fish. She did eat local street foods, so perhaps there was some fish consumed unknowingly. 

One thing that stands out in the case is the radiographic finding of track marks on the CT. This makes me think of Fascioliasis, such as with Fasciola hepatica or Fasciola gigantica, which migrate through the liver parenchyma. This is acquired by eating aquatic vegetation, classically watercress, a common salad ingredient. So overall, I think Fascioliasis is my best guess. 

A stool O&P exam (or several) may be of use here. 



Hakon writes:

Hello from cloudy athens- a tad brisk at 15 degrees F when I got up. This week’s case was quite interesting as given her history of eating salads and street food in SE Asia it seems like it could be a myriad of things. Given the liver involvement I originally went to a schistosome, but later put it lower on my list based on her only swimming in chlorinated pools. The famous ascaris suis case came to mind with the salad tidbit, but ultimately the liver lesions described seemed less likely to be ascarid migration than trematode. Ultimately, thinking back to a recent Pro-Med email where there were major case numbers in parts of Russia with tourists eating street food consisting of salted fish and developing clonorchis, that was ultimately where I decided to cast my suspicions. Especially given its prevalence in parts of Asia. Thanks for another interesting case. Best,


Margaret writes:


No need to check the weather, it’s winter in the Willamette Valley so it’s 45-55 F and drizzling.

Thank you for all that you do! So excited to submit a guess for the case report on TWIP 227! It’s like being on a gameshow but for introverts 😀


Guess: Fascioliasis due to Fasciola hepatica

Eosinophilia is similar the range reported in Saba et al 2004 Human Fascioliasis (thank you for the references in your *free* online textbook!)

Linear tracts in the liver are consistent with this organism, and the right-sided pleural effusion has been reported as well.

It is too soon to see eggs in the stool, so circulating antigen testing is probably the next step to confirm. But I have questions that I don’t have time to answer this week: can you get triclobendazole in Israel? If you can but you can’t get the serology, does this drug cover differential diagnoses with acceptable risks to the patient? Looks like Nitoxanide is a distant second choice, but what would that mean for the patient? Would they have more side effects from more extended treatment? Would they be ill for a longer period of time?

Can’t wait for the next episode.

Margaret in Oregon

I pressed send too soon – sorry

PS –

The patient didn’t think she had freshwater exposure, but some of her salads did.

Justin writes:

Hello all,

The case details made me think first of schistosomiasis. However, she denies any swimming in freshwater. Perhaps the pool was a sufficient source if the water was under treated.

Another potential I thought of would be opisthorchis, but she denies raw fish consumption making that unlikely.

And so, my guess this time will be schistosomiasis.

Thanks for a wonderful podcast as always,



Felix writes:

Dear hosts,

greetings from snowy Germany! 

Amebiasis would fit the symptoms quite well but the elevated eosinophils lead me more towards liver fluke or an ascaris. My final answer is fasciola infection since she might have enjoyed some seagrass in her salad. 

Thanks for the great podcasts 


Inge writes:

Dear professors of TWiP, 

It’s an overcast day with an unparticular average of 9 degrees Celsius in the Netherlands. As unexciting as the weather, all the more exciting the case has me, because it reminds me of a patient I treated in my year as junior doctor in which I suspected a parasitic cause of her liver abscess, but sadly it proved not to be so. The case you presented is of a 20-year old traveller to South-East Asia, with liver hypodense liver lesions with ring enhancement RUQ abdominal pain and intermittent high fever. The liver lesions described immediately make me think of an abscess, intermittent high fever would fit with this as well. Multiple parasites could cause this, for example: entamoeba histolytica, echinococcus spp., fasciola spp., toxoplasmosis and schistosomiasis. Knowing that our patient avoided swimming in freshwater makes schistosomiasis and fasciola less likely. Knowing she avoided raw and undercooked meats is suspected to have an adequate immune system, makes toxoplasmosis less likely. This makes me think of either an amoebic abscess or echinococcosis. The first being more likely to cause fevers and being more prevalent in South-East Asia, would be my guess. It would also explain an early episode of diarrhea. The distinction between the two may be important, as in the case of an amoebic abscess, one may aspirate the abscess and in echinococcosis this is contraindicated. Confirming the diagnosis could be done with stool antigen tests or stool microscopy, as well as serodiagnosis. Treatment for entamoeba histolytica would be recommended with metronidazole.

Looking forward to learning more about parasitology every time.

Kind regards, 


Jay writes:

Dear TWiPsters,

A 20 year-old female was in her otherwise good state of health until she developed fever to 39.3 degrees Celsius (101.3 degrees Fahrenheit), headache, and right upper quadrant pain about 10 weeks after returning from a two-month trip to SE and South Asia. She ate street food and salads while traveling but avoided swimming in fresh water. Labs showed a high eosinophil count, mild anemia, and mildly elevated liver enzymes. A CT scan was done showing several clustered hypodense lesions with ring enhancement, retroperitoneal lymphadenopathy, and a right pleural effusion.

Her symptoms persisted, so a CT scan was repeated two weeks later. The liver lesions progressed and now showed hypodense track marks.

I suspect this is fascioliasis, due to the liver fluke Fasciola gigantica (found in the areas of the world where she had traveled) or Fasciola hepatica (found throughout the temperate world). Herbivorous animals such as sheep or goats are the definitive hosts of this parasitic trematode. The animals release the eggs into the environment when they defecate. The eggs embryonate in fresh water, infect snails (the intermediate host), and undergo several developmental stages within the snail. Those stages eventually lead to an encysted form called the metacercariae. The metacercariae attach to the leaves of aquatic plants such watercress and water lettuce and are then eaten by humans, including our 20 year-old salad-eating world traveler. She then became the incidental host.

Roughly 6 – 12 weeks later, the acute phase of infection begins, manifesting as fever, right upper quadrant pain, and marked eosinophilia.  The hypodense tortuous tracks seen in the second CT scan are caused by migration of the fluke through the liver.

Diagnosis can be confirmed by liver biopsy or direct observation of the flatworm through ERCP. Serology can also be useful for making the diagnosis as well as tracking response to therapy. Eggs are not yet released into the stool in the acute phase, so stool studies will not help with the diagnosis at this time. Treatment is usually with triclabendazole.

It’s fun and helpful to cast a wide net when thinking about other possible causes of her symptoms. Toxocara and malaria were considered but were negative. Other parasitic and non-parasitic causes are possible. Sexual history was left out of the case description, but hopefully it was obtained. RUQ pain and fever can be seen in perihepatitis or the Fitz-Hugh Curtis Syndrome. And never forget the great mimicker, syphilis. It can also lead to fever and a “luetic jaundice” (aka syphilitic hepatitis). 

Thank you for this most interesting and challenging case, TWiPsters. Please keep ‘em coming.


Jay Gladstein, M.D. | Chief Medical Officer

APLA Health & Wellness

Olympic Medical Clinic | 5901 W. Olympic Blvd, Suite 310 | Los Angeles, CA 90036

Michelle and Alexander write:

Dear Be-Livers in Science,

 The 20 year old patient who returned from a trip to south east asia presents with a number of different symptoms and signs. By prioritizing the signs which are most specific, we can quickly come to a diagnosis.

 While eosinophilia, fever and elevated liver tests point towards a parasitic infection of the liver, this still leaves a large number of possible etiologies to test for, from schistosoma to echinococcus and from strongyloides to toxocara. The findings of the CT of the liver help narrow the differential down considerably: While a number of infections can cause ring-enhancing lesions, the tracks seen in this case are indicative of only one helminthic infection: Fasciolosis.

 This infection is most commonly caused by the trematode Fasciola hepatica, which is endemic in southeast asia and other parts of the world. The infection is acquired by eating uncooked water plants like watercress or morning glory, which harbor the parasite. The worm migrates out of the gut and into the liver, where the immature worms can cause the track marks described in the case by feeding on the liver (foie gras d’homme). Later on, the adult worms reside in the biliary tract where they can cause chronic inflammation or obstruction. The species Fasciola gigantica can also cause the disease and can often only be distinguished with NAAT.

 Symptoms in patients with Fasciola hepatica infection can include abdominal pain, nausea, vomiting and jaundice. Although the diagnosis can be tricky, antibody detection via serological testing, stool examination, ultrasound of the liver and a CT scan of the abdomen can be helpful. Stool examinations tend to be negative until the parasite has reached the biliary system. Commonly seen findings on ultrasound in later stages of the disease may include hepatomegaly, widened biliary ducts caused by inflammation and, if you’re lucky, live fluke movement through said ducts. On CT scan, hypodense lesions in the liver and periportal tracking strongly suggest Fasciola hepatica infection.

 The primary treatment for fascioliasis is the antihelmintic drug triclabendazole, which is effective against mature and immature flukes and usually given in two oral doses 12 hours apart. If necessary, medications to treat concomitant symptoms such as pain and inflammation may be prescribed as well. 

Thank you for this great case. All the best, 

Michelle and Alexander from the First Vienna Parasitology Passion Club

David writes: (Central Lancashire Parasitology Club)

Dear Vincent,

Thank you so much for the books – we are delighted to receive them and put them to good use trying to solve TWIP 227.

I have attached a picture of the current team clutching the precious volumes.

We are proud to participate in your wonderful show.

We appreciate the support you have given by providing extra books too.

Best wishes