Increasing Case Numbers and Earlier Age at Diagnosis of Alveolar Echinococcosis: Insights from a 13-Year Retrospective Swiss Study.

INTRODUCTION

Alveolar echinococcosis (AE) is a rare zoonotic infection caused by Echinococcus multilocularis. In recent years, the number of reported cases has increased across Europe, including Switzerland.

METHODS

We conducted a retrospective observational study at Lausanne University Hospital (CHUV), including all AE cases diagnosed between 2010 and 2023 within the Departments of Gastroenterology and Hepatology, Visceral Surgery, and Infectious Diseases.

RESULTS

Eighty patients with AE were identified. Half of them were male. The mean annual incidence was 0.53 cases per 100,000 population (range, 0.14-0.85), with a statistically significant increase over time in the canton of Vaud (p = 0.037). The median age at diagnosis was 61.5 years, showing a significant downward trend during the study period. At diagnosis, 45 patients (56.3%) were asymptomatic, and 17 (21.3%) were immunosuppressed. Compared with immunocompetent patients, immunosuppressed individuals more often presented asymptomatically, had significantly smaller hepatic lesions, and were more frequently seronegative.

CONCLUSIONS

This study demonstrates evolving epidemiological patterns of AE in Switzerland, characterized by increasing incidence and a high proportion of asymptomatic cases. Immunosuppressed patients tended to present with milder disease. Our findings highlight the need for strengthened surveillance and support the ongoing efforts to establish a national AE registry.