Fascioliasis surfaces sporadically in Urmia hepatobiliary patients
Among patients referred for hepatobiliary disease in Urmia, fascioliasis was uncommon but not absent. Screening sera from 313 patients between 29 October 2024 and 26 February 2025 identified four seropositive cases, a prevalence of 1.3%. The number is small, yet the clinical message is direct: parasitic infection can still sit inside a population dominated by conventional biliary diagnoses, especially when symptoms and imaging point clinicians toward stones, obstruction, or inflammatory liver disease.
One finding carries particular bedside weight. A live adult Fasciola species was retrieved endoscopically from the common bile duct of one seropositive patient who also had eosinophilia, confirming active infection during the chronic biliary phase. In practical terms, the parasite was not just a serologic signal or a historical exposure marker. It was physically present in the biliary tree, where it can reproduce the same obstructive and inflammatory pattern that often leads to workup for gallstones or other hepatobiliary disorders.
A parasite that can hide inside routine biliary workups
The study focused on a setting where freshwater snails serve as intermediate hosts and livestock are the main definitive hosts. Human infection occurs accidentally after ingesting metacercariae on aquatic plants or in contaminated water. That transmission pattern explains why the disease can persist quietly in rural environments and then present later as a diagnostic puzzle in specialty clinics rather than as an obvious outbreak.
Three of the four seropositive patients had a history of biliary stone, and three lived in rural areas. Those are descriptive observations only, because the small number of positive cases prevented formal association testing, but the pattern fits the biology of the parasite. Fasciola migrates through the liver and settles in the biliary system, where it can provoke chronic inflammation, pain, obstruction, and laboratory abnormalities that overlap with stone disease. Eosinophilia in one confirmed case adds another clue, since helminthic infection often announces itself through eosinophilic responses before the diagnosis becomes obvious.
The geographic mapping component strengthens the clinical picture even though the dataset is limited. GIS mapping of seropositive cases showed how the infection clustered in the population examined, a useful reminder that exposure risk is not random. In parasitic disease, place matters because water sources, agricultural habits, livestock contact, and local sanitation shape the chance of accidental ingestion long before a patient reaches the hospital.
Why a low prevalence still deserves attention
A 1.3% seroprevalence may appear modest, but low prevalence does not mean low consequence. Chronic fascioliasis is easy to miss because it can imitate a range of hepatobiliary conditions, from biliary colic to unexplained cholestatic symptoms. In that setting, a missed infection can prolong symptoms, delay endoscopic or antiparasitic treatment, and keep the diagnostic pathway locked onto stones or nonspecific liver disease.
The comparison with a recent survey in the same province is also clinically useful. The prevalence here was numerically higher than the 0.33% reported in another population survey from the region. The difference does not establish a trend on its own, but it does argue against dismissing fascioliasis as a negligible local issue. Even a handful of active cases matters when the parasite can occupy the common bile duct and mimic the very conditions that trigger gastrointestinal referral.
The study design matters for interpretation. This was a cross-sectional serologic survey using anti-Fasciola hepatica IgG ELISA, which captures exposure and possible infection but does not by itself prove active disease in every seropositive patient. Serology can remain positive after prior infection, which is why the direct retrieval of an adult worm in one patient stands out so sharply. It provides an anatomic confirmation that the infection can be active and clinically relevant in this population, not merely an antibody footprint from the past.
What the serology and the worm retrieval mean at the bedside
For hepatobiliary clinicians, the diagnostic lesson is straightforward. When a patient from an endemic or exposure-prone area presents with biliary symptoms, eosinophilia, gallstone history, or unexplained hepatobiliary abnormalities, parasitic infection belongs in the differential diagnosis. The common bile duct is not an intuitive hiding place for an adult fluke unless the clinician is already thinking along parasitologic lines. Once the parasite is considered, serology, imaging, and endoscopic findings can align much more quickly.
This is also a reminder that endemic infections often survive in the spaces between routine specialties. Internal medicine, gastroenterology, parasitology, and endoscopy all intersect here. A patient may first be labeled as having stone disease, then undergo additional investigation only when the course becomes atypical or eosinophilia emerges. Direct retrieval of the organism, as in this study, removes ambiguity and validates why persistent suspicion is warranted.
The data do not support broad prevalence claims beyond the sampled population, and the small number of positive cases prevents more detailed statistical modeling. Even so, the finding is valuable because it links serology, clinical correlates, rural residence, and a directly observed adult parasite in one report. In a disease with a chronic course and a habit of masquerading as other hepatobiliary problems, that combination is enough to justify vigilance.
Local exposure patterns remain the unresolved piece
The study closes with a realistic limitation: the analysis stayed descriptive because only four patients were seropositive, so no formal tests of association were performed. The exact exposure pathways behind these cases were not mapped in a way that allows causal inference from the available data. What remains uncertain is not whether fascioliasis exists in Urmia hepatobiliary patients — it clearly does — but how often clinicians are overlooking it and which local exposures are driving continued transmission.
The work was approved and supported by Urmia University of Medical Sciences and formed part of an MSc thesis in medical parasitology. Its value lies in the clinical warning embedded in the numbers: even in a hospital population dominated by more familiar biliary diagnoses, a parasitic infection can still be the hidden cause of obstruction, eosinophilia, and chronic biliary symptoms. One worm recovered from the common bile duct is enough to keep the diagnosis on the table.