How many confirmed human cases of Eurytrema pancreaticum are published, and where are they located?
Executive summary
Human infections with the pancreatic fluke Eurytrema pancreaticum are exceptionally rare in the published literature: historically there were at least two formally documented human cases by 1983, and subsequent scattered case reports—mostly from East Asia—bring the total to a small handful, with the strongest body of published evidence coming from Japan and neighboring East Asian locations [1] [2] [3]. Available sources do not provide a single, comprehensive global tally, and several reviews stress that human eurytremiasis is usually an incidental, sporadic finding rather than a well-documented clinical series [4] [5].
1. Historical baseline: "two documented cases" by early reports
Early literature framed human Eurytrema pancreaticum infection as vanishingly uncommon; the 1983 paper by Ishii and colleagues describes an autopsy in Fukuoka Prefecture, Japan, with about 15 adult flukes and explicitly calls that presentation "the second documented case of eurytremiasis in man," establishing that by that date at least two confirmed human infections had been published [1]. Citations and archival reviews collected in bibliographies and review chapters reiterate that early mid‑20th century reports (e.g., Kasahara & Iwamoto and Chang & Li) are foundational references for human occurrences, underscoring that human cases were known but very rare in the historical record [2].
2. Modern pattern: concentrated reports in Japan and East Asia
Subsequent reporting and literature reviews consistently identify Japan and East Asia as the main source of published human Eurytrema pancreaticum cases: several modern Japanese case reports and endoscopic detections are cited across parasitology reviews and regional case compilations, and archaeological finds of Eurytrema eggs point to historical East Asian presence of the parasite [3] [6] [7]. Reviews and molecular studies note that E. pancreaticum is primarily an animal parasite of ruminants across Asia (and parts of South America), and human infections are characterized as accidental or incidental—most published human detections have therefore come from regions where zoonotic exposure and traditional insect‑eating behaviors are documented, notably parts of East Asia [8] [9] [5].
3. Recent single‑case reports and ambiguity in totals
More recent literature cites isolated human case reports, including an Abdominal Radiology paper and other case notes, but none of the provided sources attempts a definitive global count; reviewers and fact‑checks describe "very few cases recorded in humans" and cite scattered modern Japanese reports plus singular later case reports [10] [4]. The CDC diagnostic resource remarks on the parasite’s rarity in human biliary/pancreatic sites and warns that eggs can be nearly identical to other trematodes, complicating definitive stool‑based diagnosis and contributing to uncertainty in case numbers [11]. Because some detections may represent incidental passage of eggs after eating infected offal or insects rather than true established infection, the literature preserves caution about treating every egg report as a confirmed, growing human case count [3].
4. Geographic negatives: where published human cases have not been documented
Multiple sources explicitly note the absence of published human cases in many regions: a systematic regional review of South Brazil states there are no published human reports from Brazil despite veterinary prevalence in animals and hypothesizes under‑detection in humans [4], while a fact‑check and expert commentary report no awareness of confirmed human cases in North America or Europe [12]. These negative statements signal where surveillance and dietary practices make human infection unlikely or undetected, but they do not constitute exhaustive proof that no human cases exist outside East Asia.
5. Bottom line and reporting limits
The honest bottom line is that published, confirmed human cases of Eurytrema pancreaticum number only a very small handful—historically at least two documented by 1983 with subsequent isolated reports concentrated in Japan and East Asia and occasional later single‑case publications—yet the exact global tally cannot be firmly stated from the provided sources because no single review compiles every published human case and diagnostic ambiguity (egg misidentification, incidental egg passage) complicates case confirmation [1] [2] [3] [11]. Where publications do exist, they place human infections primarily in Japan and neighboring East Asian locales, with reviews noting veterinary prevalence across Asia and parts of South America but no clear, confirmed human clusters outside East Asia in the available literature [8] [4] [12].