Human infestations with Fasciola hepatica in Austria between 1955 and 2025: data from a low-incidence country

Although rare, human Fasciola hepatica (FH) infestations represent a clinically relevant parasitosis that can cause significant clinical manifestations and functional limitations, particularly affecting the liver. Laboratory tests typically reveal elevated white blood cell counts and absolute or relative eosinophilia. The Department of Medical Parasitology at the Institute for Specific Prophylaxis and Tropical Medicine, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, is the national reference center for FH infestations in Austria. In this study, we assessed all confirmed human FH infestation cases between 1955 and 2025 and retrospectively analyzed their demographic, clinical, laboratory, and imaging data. In all, 64 human FH infestations were recorded. Although some patients were asymptomatic, most had fever, abdominal pain, hepatosplenomegaly, and elevated liver parameters. Pancreatitis, diarrhea, pulmonary symptoms, weight loss, or skin lesions, mainly urticaria, were present in a few cases. During the observation period, the diagnosed cases gradually increased decade by decade, largely due to improved diagnostic tests for FH. However, during the last 10 years, a decline in new diagnosed cases has been observed. Until the 1980s, cases concerned only individuals born in Austria. Since the 1990s, there have been case reports concerning people with a migration background, reflecting demographic changes. The distribution of FH cases within Austria was found to be unequal, with certain regions reporting higher incidence (Salzburg, Upper Austria, and Vorarlberg). Fasciola hepatica infestation is a rare parasitosis in Austria. However, it should be considered as a differential diagnosis, especially among migrants and travelers returning from endemic regions presenting with eosinophilia and abdominal pain.