Anisakis simplex allergy

Anisakis simplex belongs to the nematodes of the genus Anisakis (Anisakis simplex = herring worm). Anisakis simplex is an intestinal parasite that occurs in fish-eating marine mammals, such as dolphins and seals. Small crustaceans and fish act as intermediate hosts. The parasite is therefore found in molluscs and crustaceans. It is also found in the flesh of sea fish. Especially herrings and mackerels are often infested by anisakis, so herrings in up to 70%.

The allergic reaction may affect the skin, respiratory tract, gastrointestinal tract or circulatory system (up to and including anaphylactic shock). The following allergens have been identified:

• Ani s 1 with unknown function (serine protease inhibitor)
• Ani s 2 Paramyosin
• Ani s 3 Tropomyosin
• Ani s 4 Cysteine protease inhibitor
• Ani s 5 SXP/RAL-2 family protein
• Ani s 6 Serine protease inhibitor
• Ani s 7
• Ani s 8 SXP/RAL-2 family protein
• Ani s 9 SXP/RAL-2 family protein
• Ani s 10 Protein with unknown function
• Ani s 11-like protein (major allergen, detectable in 78% of anisakis-allergic patients)
• Ani s 12 Protein with unknown function
• Ani s 13 Haemoglobin
• Ani s 14 Larval protein with unknown function

The anisakis simplex allergy must be distinguished from the so-called anisakiasis, also known as anisakidosis or herring worm disease, a parasitosis of humans that is caused by the consumption of larval sea fish, if they are not or only insufficiently heated, weakly marinated or only insufficiently smoked. This gastro-intestinal infection therefore occurs mainly in countries where fish is often eaten raw or marinated (sushi), e.g. in Japan. Overall, infections with anisakis simplex seem to be rare in humans.

1. Caballero ML et al (2002) Specific IgE determination to Ani s 1, a major allergen from Anisakis simplex, is a useful tool for diagnosis. Ann Allergy Asthma Immunol 89:74-77.
2. del Pozo MD et al (1996) Laboratory determinations in Anisakis simplex allergy. J Allergy Clin Immunol 97:977-984.
3. González-Fernández J et al (2015) Haemoglobin, a new major allergen of Anisakis simplex. Int J Parasitol 45:399-407.
4. Kobayashi Y et al (2015) Molecular Cloning and Expression of a New Major Allergen, Ani s 14, from Anisakis simplex. Shokuhin Eiseigaku Zasshi 56:194-9.
5. Lorenzo S et al (2000) Usefulness of currently available methods for the diagnosis of Anisakis simplex allergy. Allergy 55:627-633.
6. Moreno-Ancillo A et al (1997) Allergic reactions to anisakis simplex parasitizing seafood. Ann Allergy Asthma Immunol 79:246-250.