Anisakiosis, also known as Anisakis larvae infestation, is an increasing parasitic infestation due to the worldwide spread of raw fish and shellfish consumption habits. We present a rare presentation of intestinal intussusception as a preoperative diagnosis and noticed it postoperatively due to Anisakis larvae. A 43-year-old man presented to the emergency department with abdominal pain around the umbilicus and vomiting for several hours. On physical examination at presentation, he had tenderness in the lower abdomen. His radiological studies showed a right-sided pseudo-kidney sign and ileo-colonic intussusception on ultrasound echography. His computed tomography images added findings of submucosal edema and wall thickening in the terminal ileum, swollen regional lymph nodes, and ascites. An urgent laparotomy was performed for ileo-colonic intussusception of an unknown cause. During the laparotomy, the ileocecal intussusception was manually reduced after dissecting the adhesion due to the previous appendectomy, and a partial ileotomy was undertaken using the Endo-GIA automatic anastomosis device. At the resected ileal wall surface, the presence of Anisakis larvae was noticed, and anisakidosis was diagnosed. The dietary history taken post-operatively revealed that he had eaten salmon, bonito, and squid sashimi four days prior to his emergency department visit. His postoperative course was uneventful, and he was discharged from the hospital on the fifth day postoperatively. Anisakiosis must be in the differential diagnosis of intussusception, and eating history seems like a cue to diagnose, and it might be meaningful to clinicians.

Consumption of raw and mildly processed seafood, in the context of modern Western world eating trends, is recognized as a major driver for human fish-borne infections. However, these zoonoses and their unfamiliar risks remain neglected and underappreciated among European diagnosticians. In contemporary Europe anisakidosis is one of the most important fish-borne zoonoses. It is caused by ingesting the third-stage infective larvae of the nematode parasites that belong to the family Anisakidae. The case described herein, is an intestinal and ectopic form of anisakiosis (Anisakis spp.), causing symptoms of subacute abdomen and masquerading as an intraperitoneal malignancy. It is the first anisakidosis case reported in Greece, affecting a young patient who had been repeatedly exposed to the parasite by consuming homemade raw fish. Right hemicolectomy, omentectomy and excision of a descending colon nodule were uneventfully performed. The pathology report confirmed granulomatous tissue with eosinophilic infiltration and parasites that were morphologically and molecularly identified as Anisakis spp. Although challenging, acquiring an accurate diagnosis of anisakidosis can prevent unnecessary surgery, as the infection typically is self-resolving, and if treatment is deemed necessary, it can be limited to antiparasitic medication. However, in rare cases, extra-gastrointestinal migration of larvae can cause severe damage with practically unknown risks, posing a diagnostic and therapeutic dilemma. In such a clinical case scenario, surgical exploration can decisively contribute to a definitive diagnosis and early identification of intraabdominal complications necessitating surgical intervention.

Members of the genera Anisakis and Pseudoterranova are the main causative agents of human anisakidosis: the disease is worldwide distributed, with major impact in countries with a large consumption of raw fish. Because of unspecific symptoms and limited diagnostic tools, incidence and burden of disease are probably underestimated. In Italy, all human infestations where the etiological agent has been properly identified, have been associated to the parasitic species Anisakis pegreffii, the most frequent anisakid in the Mediterranean area. Here, an invasive human case of pseudoterranoviasis is described for the first time in Italy: in 2015, a woman was found infected during a colonoscopy scheduled after the occurrence of nonspecific clinical symptoms. The nematode was found penetrating the ascending colon. The identification was performed by sequencing the mitochondrial region cox2 and by comparison to GenBank retrieved material using the BLAST search tool. The sample showed a 99% identity with Pseudoterranova decipiens sensu stricto. The record underlines the potential risk due to the consumption of raw or undercooked imported fishes.