SEROEPIDEMIOLOGIC SCREENING OF ECHINOCOCCUS-MULTILOCULARIS INFECTION IN A EUROPEAN AREA ENDEMIC FOR ALVEOLAR ECHINOCOCCOSIS

In a serologic survey for Echinococcus multilocularis infection, we sc reened sera from 7,884 subjects from the Doubs Departement in France, an area endemic for alveolar echinococcosis (AE) of the liver. An enzy me-linked immunosorbent assay (ELISA) with a highly species-specific a ntigen (Em2) and an E. raultilocularis crude antigen (Emc) was used fo r screening. An evaluation of the cost/benefit relationship of this sc reening, followed by therapeutic management of patients, was made and compared with the actual cost of the follow-up and treatment of the di sease in symptomatic cases in this endemic area. Antibody reactions to Em2 and/or Emc made possible the detection of eight asymptomatic clin ical cases (seroprevalence averaging 1/1,000), with typical lesions of active AE revealed by abdominal ultrasonography and computed tomograp hy. All were seropositive using the Emc ELISA but two were seronegativ e using the Em2 ELISA. In five additional seropositive cases, the radi ologic investigations revealed small calcified lesions similar to the lesions of abortive AE previously found in Alaska. The cost of this se rologic screening program per screened subject and per diagnosed case averaged 50.00 French Francs (FF) (U.S. $8.60) and 60,000.00 FF (U.S. $10,909.00), respectively. The cost of diagnosis, follow-up and treatm ent of the patients was 5,086.00 FF (U.S. $929.00) per patient per mon th in the case of diseases diagnosed by the screening program and 7,08 6.00 FF (U.S. $1,288.00) per patient per month for patients with sympt omatic AE. This survey indicates a high prevalence of AE in the target area; it confirms the long latency period of the larval growth in hum an AE and shows that abortive AE is present in Europe. The use of both the Emc and Em2 ELISAs seems to be better than using the Em2 ELISA al one. The cost of the hospitalization and treatment of the eight screen ed patients would appear to be relatively high. Even though two of the m were asymptomatic, they had very severe forms of the disease. In fac t, the total cost was much lower than the actual cost of the disease w hen diagnosed from clinical symptoms.