Long-term seropositivity against Echinococcus multilocularis in an epidemiological follow-up study in southwestern Germany (Romerstein)

Background: Out of 2,560 participants in an epidemiological survey of alveolar echinococcosis (AE) performed in 1996 in southwestern Germany, 47 participants had tested seropositive in one of two crude antigen screening ELISAs and were inconspicuous on hepatic ultrasound. Patients and Methods: Out of these 47 seroreactors, 36 attended a follow-up examination 30 months after the primary examination, including ultrasound and serology with various Echinococcus multilocularis-specific antigens. Results: No lesion suspicious for AE was detected in any participant. Serology showed only minor changes as compared to the earlier results. Conclusion: Persistent seropositivity without detectable hepatic lesions could be interpreted as an early sign of sonographically not yet detectable AE, immunity to E. multilocularis or unspecific serological reactivity. For seropositive and clinically inconspicuous inhabitants of areas endemic for AE follow-up examinations at intervals of 2-3 years seem to be adequate.