The raw seafood used in foods such as sushi and sashimi may contain parasitic worms that can cause relatively mild to severe infections in humans. Anisakis simplex is the most likely offender when it comes to parasitic infections from these now common foods.

Sushi public domain image/Luke via wikimedia commons
Sushi public domain image/Luke via wikimedia commons

Anisakis is a marine roundworm that can be found in over 200 species of fish, eel and octopus. When you eat raw seafood contaminated with this roundworm, you are ingesting live larval forms of the parasite.

From as soon as 1 hour to 2 weeks after eating the sushi, the symptoms may begin. The worms typically attached themselves to the stomach where vomiting and abdominal pain will ensue. More severe symptoms may be abdominal pains resembling appendicitis and rarely bowel obstructions.

Typically, in this country, people discover they have this parasite when they feel a tickling sensation in the throat and actually cough up the worm.

This parasite rarely achieves maturity in the human host and eventually dies in a few weeks. The dead worms however stimulate an inflammatory response, which can cause allergic type symptoms.

There is no antibiotic or other pill to take for treating Anisakis. Removing the worm surgically may be the only way to alleviate pain in very severe cases.

The good news is that this food borne illness is quite rare in the United States with only approximately 10 cases reported annually, although it is speculated that many mild cases are not reported.

How do you prevent getting this potentially painful parasite? The Food and Drug Administration recommends that all seafood intended for raw consumption be either blast frozen (-35ºC) for at least 15 hours or regularly frozen for 7 days which will kill the parasite. Go to reputable restaurants that surely follow these health and safety guidelines. Don’t prepare your own sushi from fish you caught yourself.

This disease should be considered if you‘ve had recently eaten sushi or sashimi and have symptoms of an allergic reaction with abdominal pain.