Anisakiasis and Gastroallergic Reactions Associated with Anisakis pegreffii Infection, Italy

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Suggested Citation

Simonetta Mattiucci

, Paolo Fazii, Alba De Rosa, Michela Paoletti, Angelo Salomone Megna, Antonio Glielmo, Maurizio De Angelis, Antonella Costa, Costantino Meucci, Vito Calvaruso, Italo Sorrentini, Giuseppe Palma, Fabrizio Bruschi, and Giuseppe Nascetti

Author affiliations: Author affiliations: Sapienza University of Rome, Rome, Italy (S. Mattiucci, A. De Rosa); Umberto I Hospital, Rome (S. Mattiucci, M. De Angelis); Hospital S. Spirito, Pescara, Italy (P. Fazii); Tuscia University, Viterbo, Italy (M. Paoletti, G. Nascetti); G. Rummo Hospital, Benevento, Italy (A. Salomone Megna, A. Glielmo, I. Sorrentini); Istituto Zooprofilattico Sperimentale della Sicilia, Palermo, Italy (A. Costa); A. Maresca Hospital, Naples, Italy (C. Meucci); F. Lotti Hospital, Pontedera, Pisa, Italy (V. Calvaruso); The National Federation of Fishery Companies, Rome (G. Palma); University of Pisa, Pisa (F. Bruschi)

Abstract

Human cases of gastric anisakiasis caused by the zoonotic parasite Anisakis pegreffii are increasing in Italy. The disease is caused by ingestion of larval nematodes in lightly cooked or raw seafood. Because symptoms are vague and serodiagnosis is difficult, the disease is often misdiagnosed and cases are understimated.

Human anisakiasis is a seafoodborne parasitic zoonosis caused by larval nematodes of the genus Anisakis. Humans are accidental hosts of the nematodes; they become infected by consuming raw or undercooked seafoods that harbor the nematode larvae in their flesh and muscle (1). The larvae do not further develop in humans; however, they can penetrate the gastrointestinal tract and form eosinophilic granulomas, often with pathologic consequences. There is a growing awareness that these parasites generate potentially life-threatening allergic reactions (2) when the live parasite attempts to penetrate the gastric mucosa. These reactions, termed gastroallergic anisakiasis, are characterized by urticaria, occurring generally on the arms and abdomen, and by angioedema or anaphylaxis (3).
The development of molecular tools for the diagnosis of human anisakiasis and greater awareness of this parasitic disease have led to an increase in the recorded number of cases of the disease during the past 20 years in many parts of the world (4). Two species of the genus Anisakis have been found to cause infections in humans: A. simplex sensu stricto and A. pegreffii (1), as has been confirmed by molecular markers (4–7). Although Anisakis spp. larvae are found in fish and squid worldwide, the prevalence of human infection is highest in countries where eating raw fish is widespread. However, the molecular identification of human cases is still scarce, especially in some European countries where allergic symptoms and hypersensitivity associated with the parasite have been reported (2).
In this study, we report several new cases of gastric anisakiasis in Italy. Identifying the etiologic agent is challenging because Anisakis spp. larvae lack morphologic features that could be used to identify them at the species level. When larvae infest humans, they can become spoiled or fragmented, making it impossible to identify them at the genus level. We performed sequencing of nuclear and mitochondrial genes to identify the parasites and to gather data on the possible association between pathologic findings of human anisakiasis and different Anisakis spp. or haplotypes. In addition, serum samples from the patients were tested for IgE reactivity against specific antigens or allergens (IgE-As) of A. pegreffii.