Case of acute ileus caused by a spirurina larva

A growing body of clinical cases suggests that a kind of nematode larva, type X larva of the suborder Spirurina that inhabits firefly squids (Watasenia scintillans, or 'Hotaru-ika' in Japanese), can cause acute ileus in humans. However, the larva itself has rarely been found in the wall of the obstructed intestine. We describe here a case of acute ileus, in which a type X spirurina larva was found histologically. A 60-year-old Japanese man suffered from acute abdomen, and an emergency laparotomy revealed a marked stenosis of the ileum. Histological study of the surgically resected ileum showed severe eosinophilic enteritis and a nematode larva. The morphological features of this larva were identical to those of the type X spirurina larva. Interestingly, the larva that was found existed within a small blood vessel, suggesting that the larva migrans of type X spirurina can take place via vasculature. The patient in the present case did not recall ingesting raw squids prior to the onset of his disease. Hence, this indicates that even if the ingestion of raw firefly squids is uncertain, spirurina infection should be included in the differential diagnosis of acute ileus or eosinophilic enteritis.