Chronic Cholestatic Liver Disease Induced by Larval Ascariasis: Novel Insights Into Immune-Mediated Pathogenesis and Hepatic Fibrosis in Mice.

Ascariasis is a widespread helminthic infection, yet the long-term hepatic consequences of larval migration remain poorly understood. Evidence indicates that tissue damage may persist beyond parasite clearance. While chronic cholestatic liver disease is classically associated with obstructive, autoimmune, or genetic disorders, parasitic infections such as ascariasis may represent an overlooked etiology. This study investigated post-migratory hepatic effects of Ascaris suum larvae in a mouse model, evaluating dose-dependent and exposure-frequency paradigms. Female BALB/c mice were infected with A. suum eggs using low-dose (250 eggs) or high-dose (2500 eggs), administered as single or reinfection (14 days apart). Mice were euthanized at three time points, day 4 post-infection (dpi) (peak hepatic migration phase), or 35 and 100 dpi (post-hepatic clearance). Livers were analyzed for parasite burden (4 dpi), cytokine gene expression, and comprehensive histopathological analysis (35/100 dpi). Plasma was assessed for biochemical markers (AST, ALT, GGT, ALP, total bilirubin and fractions, and albumin) and cytokine quantification. Histological analysis revealed persistent hepatic inflammation and fibrotic remodeling up to 100 dpi. Biochemical assays confirmed cholestatic dysfunction with elevated ALP, GGT, and bilirubin. Gene expression analysis showed sustained inflammatory signaling. These findings establish that larval migration induces chronic hepatobiliary injury and cholestasis, independent of peak burden. Importantly, pathology occurred without adult worm-mediated biliary obstruction, identifying a novel helminth-driven hepatic disease mechanism. Our findings demonstrated that ascariasis, even at low infection intensities and in the absence of adult worm establishment, can induce persistent hepatic inflammation, fibrotic progression, and cholestatic dysfunction. This evidence challenges the prevailing paradigm that biliary obstruction by adult worms is the exclusive mechanism of hepatobiliary injury in ascariasis. Our results underscore the significant pathogenic potential of larval stages and their ability to provoke chronic liver pathology that persists well beyond parasite clearance. These observations are clinically relevant for endemic regions, where recurrent low-level exposure may lead to cumulative liver damage despite the absence of overt adult worm infection.