Anisakiasis Symptoms Causes Treatment and Prevention
What is Anisakiasis?
Anisakiasis or herring worm disease (анизакидоз, أنيساكيدا) is a parasitic disease caused by ingestion of parasitic nematodes of the the genus Anisakis (worms). Anisakid nematodes (anisakis larvae) can invade the gastrointestinal wall of humans.
Ascaridoidea or herringworm have a life cycle involving marine mammals and fish.
The disease occurs mainly in Japan, northwest europe (the Netherlands and Scandinavia) and Latin America where people commonly eat uncooked and inadequately treated saltwater fish, squid or octopus (salted, frozen, marinated, or smoked).
Individuals who eat sushi, sashimi, herring, gravlax, or ceviche are at increased risk of developing anisakiasis.
What are the signs and symptoms of Anisakiasis?
Gastric symptoms such as severe abdominal pain, nausea, vomiting, and diarrhea may develop within a few hours after ingestion. However, severe bowel symptoms such as abdominal distention, bloody diarrhea, mucus and blood in stool with abdominal pain and mild fever occur within a few days or weeks, depending on the location and size of anisakis larvae. Parasites induced skin allergy with itchy rash, and less commonly, anaphylaxis, can also develop.
What are the causes of anisakiasis?
Anisakiasis is caused by ingestion of parasitic nematodes of the the genus Anisakis (worms) that invade the gastrointestinal wall of humans and attach to the inner lining of the esophagus, stomach or intestines.
How to diagnose anisakiasis?
Diagnosis can be made by:
1- History disease and Case study
Enteric anisakiasis is difficult to suspect; however, an accurate history of having eaten raw or undercooked fish before the onset of symptoms can be used to help confirm diagnosis.
2- Endoscopy and Histopathology
Gastroscopy or upper gastrointestinal endoscopy is a procedure where an endoscope is used to examine inside the esophagus, stomach and duodenum. It is performed to detect and remove larvae.
Biopsy and histological assessment of tissue samples removed during endoscopy.
How to treat anisakiasis?
The treatment of choice for anisakiasis require endoscopic or surgical removal of the worm from the body.
How can anisakis be prevented?
The optimal way to prevent anisakis is to avoid eating raw or undercooked fish or seafood.
Clean and eviscerate fish directly after catching them and adequately freeze them for seven days at -4°F (-20°C) or freeze them for 15 hours at -31°F (-35°C) or below and adequately cook fish and seafood at 149° F (65° C) before eating; However, adequate freezing or cooking can kill all of the infectious larvae, but it will not protect sensitized patients from allergen exposure.
Verified by: Dr.Diab (December 19, 2023)
Citation: Dr.Diab. (December 19, 2023). Anisakiasis Symptoms Causes Treatment and Prevention. Medcoi Journal of Medicine, 15(2). urn:medcoi:article18042.