Objective: Infection with the fish-borne liver fluke Opisthorchis felineus, which is transmitted through the consumption of raw or undercooked fish, results in serious liver damage in humans. Currently, limited clinical and experimental data reveal kidney damage co-occurring with chronic opisthorchiasis. We conducted a retrospective analysis of kidney autopsy samples over a five-year period (n = 84). The aim of the study was to assess pathomorphological changes in the kidneys and evaluate whether there is an association between IgA nephropathy and liver fluke infection.

Methods: Histological analysis, immunohistochemistry, and statistical analysis were performed.

Results: In this study, we demonstrated for the first time that chronic O. felineus infection in humans was associated with tubular dystrophy, the accumulation of renal tubular casts, and glomerulosclerosis. The hypertension increases the pathomorphological changes associated with chronic opisthorchiasis. We also detected IgA and the O. felineus total antigen in glomeruli of infected people. Fisher's test showed a significant association between O. felineus infection and IgA nephropathy, as well as between O. felineus infection and glomerulosclerosis.

Conclusions: Therefore, the findings of this study highlight the importance of recognising O. felineus infection as a more than hepatobiliary disease and emphasise the need for careful, personalised monitoring of kidney function in infected individuals.