Human anisakiasis in Italy: A retrospective epidemiological study over two decades

A retrospective analysis on human anisakiasis in Italy since its first description in 1996 was performed by conducting a literature search. Inclusion criteria based on the presence of a larva and on parasite identification were applied. Epidemiological data and clinical features were analysed. Particular attention was paid to the source of infection. In total, 73 cases were included in the analysis, while 34 were excluded. Cases were reported from eight Italian regions, most frequently Abruzzo, Apulia and Latium. The parasite was detected by endoscopy (51.4%) or laparotomy (48.6%). The site of infection was intestinal (42.5%), gastric (43.8%), oesophageal (1.4%) or ectopic (12.3%). Most of the parasites (71.0%) were identified as Anisakis sp. or A. simplex (s.l.). However, when molecular methods were used (21 cases), A. pegreffii was always identified. In most of the patients (65.7%), the source of infection was raw or undercooked anchovies, followed by "anchovies or sardines" (15.1%), generic "raw seafood" (15.1%), and sardines (1.4%). In only 2 cases (2.7%), the source was not available. This is the first systematic analysis of Italian cases of anisakiasis. The main conclusions derived from the results are: i) attention should be given to the history, in particular when raw marinated anchovies, proven to be the main source of human anisakiasis in Italy, are consumed; ii) in order to assess correct epidemiological data, a confirmed and specific etiological identification should always be sought.