What documented human cases of eurytremiasis exist and what treatments were used?
Executive summary
Human eurytremiasis—infection of people by the pancreatic fluke Eurytrema pancreaticum—is exceedingly rare but documented in the medical literature by a handful of case reports spanning Japan and more recently a surgically resected case described in 2019; treatment approaches reported include surgical resection when the infection mimicked pancreatic tumor and antiparasitic drug therapy, most often praziquantel in published reviews [1] [2] [3]. Consensus in parasitology reviews is that praziquantel 25 mg/kg three times in one day is the most commonly used regimen for human eurytremiasis, while some related trematode infections have also been treated with triclabendazole [3] [4].
1. Documented cases—what the literature actually records
The earliest and most-cited human reports come from Japan in the early 1980s: an autopsy of a 70‑year‑old woman found about 15 adult Eurytrema pancreaticum worms in dilated pancreatic ducts (reported in PubMed indexed work) and a contemporaneous surgical report demonstrated adult pancreatic flukes in a resected pancreas (Takaoka et al.) [1] [5] [6]. Several other case reports and small series from Asia reviewed across the decades (including Ishii et al.) document only about a dozen human infections historically, emphasizing that human cases are rare compared with high prevalence in ruminant hosts [7] [8]. The most recent detailed imaging and pathological report describes a 43‑year‑old man who presented with obstructive jaundice and a presumed pancreatic tumor and underwent subtotal stomach‑preserving pancreaticoduodenectomy; multifocal granulomatous lesions and numerous parasite eggs on histology led to the final diagnosis of pancreatic eurytremiasis [2] [9]. Review articles and book chapters reiterate these as the bulk of documented human presentations and note occasional detections by endoscopic pancreatography [9] [10].
2. How patients presented and how diagnoses were established
Reported human infections have ranged from incidental autopsy findings to symptomatic presentations mimicking pancreatic neoplasm with obstructive jaundice; in the surgical 43‑year‑old case, liver enzymes were elevated and imaging suggested a pancreatic tumor before histology revealed parasite eggs and granulomas [2]. Other diagnostic pathways in older reports included endoscopic retrograde pancreatography and resection specimens that directly showed adult flukes in pancreatic ducts [9] [11]. Reviews stress that routine stool tests may miss infections and that cases can be subclinical or mistaken for other pancreatic disease, which complicates detection [7].
3. Treatments used and the evidence base
Antiparasitic therapy recommended in parasitology reviews for human eurytremiasis most commonly cites praziquantel 25 mg/kg three times in one day as the successful regimen reported in case-level treatments; triclabendazole (10 mg/kg single dose) is documented as effective for related fluke dicrocoeliasis and has been used in single-case contexts for trematode infections, but praziquantel is the drug most often mentioned for eurytremiasis specifically [3] [4]. In contrast, some published human cases were managed surgically—either because the lesion was presumed neoplastic preoperatively or because diagnosis was established only on resection specimens—illustrated by the 43‑year‑old who underwent pancreaticoduodenectomy [2]. Older autopsy cases, by definition, received no antemortem antiparasitic therapy [1].
4. Limits, controversies and practical takeaways
Parasitologists caution that human infections are accidental, rare, and likely tied to unusual exposures such as ingestion of infected insects in regions where entomophagy occurs; consequently, the zoonotic risk is considered extremely low in most countries and the absence of reported cases in places like Brazil is debated but argued by some experts to reflect life‑cycle constraints rather than only underdetection [7] [8]. The evidence for optimal pharmacologic treatment in humans is necessarily limited to small numbers and extrapolations from related trematodes; while praziquantel is the most frequently cited successful agent in reviews, randomized or comparative data do not exist for human eurytremiasis [3] [4]. Reporting gaps mean firm, universal treatment algorithms cannot be drawn from the current literature.