Anisakis is a parasitic disease caused by Anisakis larvae , which can infect the stomach and intestines, resulting in symptoms such as severe abdominal pain, fever and nausea.
This type of parasite is usually present in the contaminated meat of fish and squid and therefore in crops where there is a habit of eating raw food, as in Japanese food sushi, for example, there is a greater risk of developing the disease .
Thus, when symptoms of general malaise or abdominal pain occur a few hours after eating sushi, it is advisable to consult a general practitioner to identify if there is any larvae of this parasite, starting 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 faeces;
- Fever below 39ºC, constant.
In addition, some people may also develop typical symptoms of allergic reactions such as itching and redness in the skin, swelling of the face or difficulty breathing.
How to confirm the diagnosis
The doctor may suspect anisachiasis after assessing the symptoms and history of each person, especially if there has been consumption of raw fish or sushi. However, the only way to confirm the diagnosis is to do an endoscopy to look for 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 is the treatment done?
In most cases, Anisakis larva infection is treated during endoscopy. To do this, the doctor, after identifying the parasite, inserts a special device through the tube of the endoscope so as to reach the stomach and remove the larvae.
However, when this is not possible or when the larva has already spread to the gut, it may be necessary to take a vermifuge, called Albendazole, for 3 to 5 days to kill the parasite and eliminate it in the feces.
In the more severe cases, where anisachiasis continues to worsen after these two treatments, it may be advisable to have surgery to remove each larvae individually.
In many cases, the body also ends up killing the larvae naturally, so many people may not even know they have been infected.
Biological cycle of anisachiasis
Anisakis is caused by Anisakis larvae and their life cycle begins when some aquatic mammals, such as whales or infected sea lions, defecate in the sea, releasing eggs that eventually develop and form new larvae. These larvae are then ingested by crustaceans, which end up being eaten by squid and fish, also becoming infectaphos.
When these fish are caught, the larvae continue to grow in their flesh and therefore chaos are eaten raw, the larvae will live inside the stomach and intestine of the person who ingested the infected fish meat.
How to avoid anisachiasis
The best way to avoid infection by this type of larva is to cook the fish and the calamari at temperatures above 65º C. However, when it is necessary to consume the raw fish, as in sushi, it is recommended to have some storage precautions.
To store the fish before eating it should be frozen, following the following guidelines:
- Freeze and store at -20º C : up to 7 dais;
- Freeze and store at - 35 ° C : for less than 15 hours;
- Freeze at -35 ° C and store at -20 ° C : 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 observed in the meat of the fish. That way, if you are eating at a sushi restaurant, for example, you should be aware of the pieces before eating.
