Imported human Schistosoma japonicum: A report on two cases in Filipino migrants present in Italy and a systematic review of literature

Background: Schistosoma japonicum is endemic in the Philippines, China, and Indonesia, and is the third-most common schistosoma species. The infection can be asymptomatic for years but, if left untreated, can lead to irreversible complications. Method: We report the results of a systematic review of the literature on imported S. japonicum infection and describe two previously unpublished cases diagnosed in Filipino migrants in Italy. Results: Twenty-five imported cases of S. japonicum schistosomiasis were retrieved. All patients but one were migrants. Most subjects acquired the infection in Philippines (n = 18, 72%). Median age at diagnosis was 46 years. Median period of residence in non-endemic countries before diagnosis was 14.5 years. Cases of prevalent hepatosplenic involvement were 10 (40%), those with prevalent intestinal involvement were 10 (40%), whereas five (20%) had overlapping manifestations. Ten patients suffered from cirrhosis; two underwent liver transplantation. Three patients presented with acute abdomen due to intestinal complications, leading to explorative laparotomy. In all cases, but one, the diagnosis was based on a histological examination of biopsy specimen, revealing S. japonicum ova. Seventeen patients were treated with praziquantel, and in three of them, possible treatment failures occurred. Conclusions: S. japonicum infection is uncommonly reported in non-endemic areas, but is probably underestimated because of a low threshold awareness of clinicians and unavailability of specific diagnostic tools. Viable S. japonicum adults may persist for decades, indicating that migrants or travellers previously exposed in areas with high-risk areas can harbour viable worms and deserve treatment.