Eating sushi and raw fish can cause parasitic disease

Anisakiasis is a parasitic disease caused by the larva Anisakis, which can infect the stomach and intestine, resulting in symptoms such as severe abdominal pain, fever and nausea.

This type of parasite is usually present in contaminated fish and squid meat and, therefore, in cultures in which there is a habit of eating raw food, such as sushi in Japanese food, for example, there is a greater risk of developing the disease..

Thus, when symptoms of general malaise or abdominal pain appear a few hours after eating sushi, it is advisable to consult a general practitioner to identify if there is a presence of any larva of this parasite, initiating the appropriate treatment.

Main symptoms

The most common symptoms of this type of parasite in the body include:

• Severe abdominal pain; Nausea and vomiting; Swelling of the belly; Diarrhea; Presence of blood in the stool; Fever below 39ºC, constant.

In addition, some people may also develop symptoms typical of allergic reactions, such as itchiness and redness of the skin, swelling of the face or difficulty breathing.

How to confirm the diagnosis

The doctor may suspect anisakiasis after assessing each person's symptoms and history, especially if raw fish or sushi has been consumed. However, the only way to confirm the diagnosis is to perform an endoscopy to observe the presence of the larva inside the stomach or in the initial portion of the intestine.

During endoscopy, if larvae are identified, the doctor can remove them using a special device that reaches the stomach through the tube used during endoscopy.

How the treatment is done

In most cases, Anisakis larva infection is treated during endoscopy. For this, the doctor, after identifying the parasite, inserts a special device through the endoscope tube in order to reach the stomach and remove the larvae.

However, when this is not possible or when the larva has already spread to the intestine, it may be necessary to take a dewormer, called Albendazole, for 3 to 5 days, to kill the parasite and eliminate it in the feces.

In the most severe cases, in which anisakiasis continues to worsen after these two treatments, it may be advisable to have surgery to remove each larva individually.

In many cases, the body also ends up eliminating the larvae naturally, so many people may not even know they have been infected.

Anisakiasis biological cycle

Anisakiasis is caused by the Anisakis larva and its life cycle begins when some aquatic mammals, such as infected whales or sea lions, defecate in the sea, releasing eggs that eventually develop and form new larvae. These larvae are then eaten by crustaceans, which end up being eaten by squid and fish, and are also infected.

When these fish are caught, the larvae continue to grow in their flesh and, therefore, chaos is eaten raw, the larvae will live inside the stomach and intestine of the person who ingested the infected fish meat.

How to prevent anischiasis

The best way to avoid infection with this type of larva is to cook fish and squid at temperatures above 65º C. However, when it is necessary to consume raw fish, as in sushi, it is recommended to take some storage precautions.

To store the fish before eating it must be frozen, following the following guidelines:

• Freeze and store at - 20º C: up to 7 dais; Freeze and store at - 35ºC: for less than 15 hours; Freeze at - 35º C and store at - 20ºC: up to 25 hours.

The type of fish most affected by this larva is usually salmon, squid, cod, herring, mackerel, halibut and anchovies.

In addition, the larva usually has more than 1 cm and, therefore, can be seen in the flesh of the fish. Thus, if you are eating at a sushi restaurant, for example, you must be attentive to the pieces before eating.