[Echinococcosis: the threat of the urban fox].

The incidence of alveolar echinococcosis in Switzerland is on the rise, probably due to the proliferation of foxes observed between 1980 and 1995 in both urban and rural areas. This is nevertheless a rare disease as humans are not a natural host for the parasite. Hepatic tumor-like lesions discovered during a workup for jaundice or abdominal pain is the most frequent mode of presentation. In the presence of typical radiological features (echography, CT-Scan, MRI), diagnostic confirmation can be made by serology. If diagnosis remains doubtful, a biopsy of the lesion with histopathological examination and PCR is indicated. Curative radical surgery is possible in only 25 to 35% of cases. In non-operable cases, long standing antiparasitic therapy allows to stop the progression of lesions.