Anisakis is the digestive disorder and allergic reaction that can be caused by the consumption of fish or cephalopods such as squid, octopus, cuttlefish, etc. affected by a parasite known as anisakis that lives in the sea. This parasite passes into our digestive system as long as the fish has been consumed raw or its preparation has not been sufficient to eliminate it.

Anisakis is a parasite that can be present in any type of fish that we usually consume whether it is raw, undercooked or subjected to treatments such as marinated or smoked dishes.

Our body’s reaction to anisakis can lead to episodes of gastroenteritis that appear 24 or 48 hours after ingesting the contaminated product:

-Stomachache

-Vomiting and nausea

-Diarrhea

– Allergy, which usually manifests itself shortly after eating fish or cephalopods, with episodes of hives that, if not treated properly, can be complicated to very serious episodes of anaphylactic shock.

The appearance of clear symptoms that affect the digestive system or the appearance of allergy episodes after eating fish allows relatively clear diagnoses. Through tests, it is possible to locate in the blood a high level of eosinophils (white blood cells very typical of worm infection and allergies).

Upper digestive endoscopy and biopsy are methods of stopping the presence of the parasite in the stomach and duodenum. Less common, although also possible, is the X-ray of the digestive tract with the use of a contrast that allows the localization of the anisakis.

Usually, symptomatic treatment of anisakis with antibiotics to stop intestinal discomfort and irritation; Antihistamines and corticosteroids for allergic symptoms (adrenaline for more severe cases) are the most effective treatment for milder cases.

It is possible, however, to resort to upper digestive endoscopy in those situations in which the parasite settles in the mucosa of the digestive tract and remains there. Specialists must resort to surgery when the case is complicated by the risk of intestinal obstruction or peritonitis due to delayed elimination of anisakis.

– Buy the fish clean and without viscera (without guts) or remove them as soon as possible, taking into account that the presence of anisakis can be high in hake, sea bream, anchovies, whiting, redfish, haddock, fresh cod, horse mackerel…

– Cooking, frying, baking or grilling are preparations that destroy the parasite, starting at a temperature of 60° C for at least one minute throughout the piece.

– With crustaceans (lobster, prawn, lobster, shrimp, shrimp, crab, crab, etc.), the same technique should be used: eat them cooked or grilled.

– Previously freeze the fish that you intend to consume raw or subjected to preparations that do not eliminate the parasite.

– For freezing, the refrigerator must reach a temperature of -20 ºC or lower. Keep the product frozen for five days. Only refrigerators rated three stars or higher reach the proper temperature. If it is not possible to do it at home, buy the fish already frozen.

The greatest prevention is to freeze any of these specialties that are usually prepared at home:

– Pickled anchovies and other pickled fish.

– Sashimi, sushi, carpaccio and other specialties based on raw fish.

– Marinated fish (ceviche).

-Raw or practically raw fish eggs.

– Herrings and other raw fish prepared in brine or lightly salted.

– Marine fish subjected to cold smoking.

They do not need to go through the freezer:

– Oysters, mussels, clams, cockles and other bivalve mollusks.

– Fish from inland waters (rivers, lakes, swamps…) and freshwater fish farms such as trout, carp, etc…

– Semi-preserved foods such as anchovies (in metal, glass or other presentations).

– Traditionally salted dried fish, such as cod or mojamas.