HUMAN ECHINOCOCCOSIS IN SWITZERLAND, 1984 -1992

In a retrospective study (1984-1992), new cases of human echinococcosi s were registered in Switzerland based on information obtained from (a ) questionnaires sent to 294 of the 300 acute hospitals in all parts o f the country and to 17 institutes of pathology (268 answers form hosp itals: 91%), and (b) from tracing back cases reported under the offici al notification system since 1 January 1988 by laboratories to the Fed eral Health Office or recorded at the Institute of Parasitology in Zur ich. Cases were regarded as verified if the diagnosis was documented b y unequivocal findings (by radiology, ultrasonography, pathomorphology etc. and often by additional detection of anti-Echimococcus antibodie s). Patients with antibodies but without reports on further findings w ere classified as suspected cases. From 1984 to 1882 (9 years), 302 ne w cases of human echinococcosis were diagnosed in Switzerland and veri fied in this study corresponding to an annual average of 34 new cases and a range between 26 and 43 cases. The total number of 302 cases inc luded 228 (75%) of cystic echinococcosis (CE) (Echinococcus granulosus ), 65 (22%) of alveolar echinococcosis (AE) (E. multilocularis), and 9 (3%) of non-specified echinococcosis (NSE) (Echinococcus sp.). Among 185 patients with CE and 60 patients with AE and known geographic orig in, the ratio of Swiss nationals to foreigners was 25% : 75% and 88% : 12% respectively. Based on a total population (Swiss nationals and fo reigners) of 6.62 million in 1988 and the case numbers of 1984-1999, t he following average annual incidence rates per 100000 inhabitants wer e calculated: 0.51 for all new cases, 0.38 for CE, 0.11 for AE and 0.0 1 for NSE. In the 37 years since 1956 there has been steady increase i n new cases of CE due to the importation of such cases by foreigners, whereas the case numbers of AE have remained nearly constant with a ra nge between 7 and 10 new cases per year. In our study 258 suspected se ropositive patients were registered but not added to the total number of cases, due to the lack of further findings.