How many confirmed human cases of Eurytrema pancreaticum infection have been reported worldwide and what were their presentations?
Executive summary
Published medical literature records only a very small number of confirmed human infections with the pancreatic fluke Eurytrema pancreaticum — described in the literature as a rare, incidental or sporadic zoonosis mostly reported from Japan and a few other East Asian locales [1] [2] [3]. Case presentations range from incidental autopsy findings to symptomatic pancreatic or biliary obstruction that mimicked a tumor on imaging, but the exact global case count cannot be confidently stated from the available sources because no single comprehensive registry or review enumerates every confirmed human case [1] [4] [2].
1. What the sources actually document about case numbers
The primary peer‑reviewed case literature treats human eurytremiasis as extremely uncommon and reports only a handful of documented individual human infections; for example, the 1983 American Journal of Tropical Medicine and Hygiene report describes a 70‑year‑old Japanese woman found at autopsy with about 15 adult flukes and states that this was the “second documented case” in humans [5] [1]. parasitology">Archaeoparasitology and regional parasitology reviews note “several” modern Japanese human infections and cite earlier 20th‑century reports, but none of the sources provide a definitive worldwide tally or a contemporary total count [2] [6].
2. Geographic pattern: where confirmed human cases appear in the literature
The literature consistently places most documented human reports in East Asia, particularly Japan, and treats human infection as an incidental or accidental spillover from livestock cycles; review articles and parasitology studies emphasize that E. pancreaticum commonly infects ruminants and only “occasionally infects humans,” with Japan hosting the majority of reported human cases in modern literature [3] [7] [2]. Regional surveys such as a South Brazil review explicitly state there are no published human reports in Brazil, reinforcing the patchy geographic footprint of confirmed human cases [8].
3. Clinical presentations reported in confirmed cases
Documented human presentations fall into two broad patterns in the case literature: clinically silent/incidental detections and symptomatic pancreatic/biliary disease. The 70‑year‑old autopsy case was an incidental finding in a patient with gastric cancer and showed normal peripheral eosinophil counts despite 15 adult flukes in the pancreatic ducts [1] [5]. Conversely, a recent comprehensive imaging case describes a 43‑year‑old man who presented with obstructive jaundice and a pancreatic mass indistinguishable from a tumor on initial workup; imaging and pathology ultimately identified E. pancreaticum as the cause [4]. Other reports referenced in the literature include detection by endoscopic retrograde pancreatography, indicating that infection can produce ductal changes visible on endoscopic imaging [9].
4. How the parasite causes these findings and the likely route of human infection
Authors and experts emphasize that E. pancreaticum normally inhabits the pancreatic ducts of ruminants and that human infection appears to be accidental and foodborne — typically through ingestion of infected intermediate insect hosts such as grasshoppers or crickets — making human cases rare events tied to dietary practices rather than efficient human‑to‑human transmission [7] [10]. The parasite’s usual localization in pancreatic ducts, and occasionally bile ducts or small intestine, explains why infected humans may be asymptomatic or may present with ductal obstruction and jaundice [2] [11].
5. Limits of the reporting and the honest answer about total confirmed cases
No source in the provided corpus compiles a definitive global count; the best-supported statement from the literature is that only a very small number of confirmed human infections have been published (described as “second documented case” in 1983, “several” in Japan across historic and modern reports, plus isolated later case reports including the 43‑year‑old with obstructive jaundice), implying a total in the low single digits to low tens rather than hundreds [1] [2] [4]. Because there is no centralized registry or global review enumerating every confirmed human Eurytrema pancreaticum infection in the provided sources, a precise worldwide case number cannot be asserted from this dataset; the literature consistently characterizes human infection as rare and sporadic [3] [10].