The A-Word

Let’s be honest, everyone feels at least a little uneasy on their first time trying sushi. More specifically, raw sushi.

While some forms of sushi don’t contain any raw fish, many others contain uncooked tuna, salmon, or yellowtail meat. While rare, the chances of contacting a food borne illness is always a possibility with raw fish.

I still remember when I watched Monsters Inside Me, a show on the Animal Planet channel detailing accounts of when different parasites got inside a human’s body and caused severe illnesses. While many episodes did nothing more than intrigue me, one episode stood out: in it, a woman suffered a severe parasite infection from eating a plate of sushi. Unfortunately, that scared me.

I have always been a sushi-lover. Growing up in a family of seafood-enthusiasts, I have relished in fish, crab, shellfish, and even the occasional exotic dish such as shark-fin soup, for as long as I can remember. Unlike my parents however, I also preferred seafood raw. Sushi satisfied that desire.

The show I watched that day dealt with a certain parasite – Anisakis simplex – or more correctly, a nematode (a worm). Its life cycle revolves around fish and marine animals, starting off with a seal. Eugene Kaplan explains in his work It Hardly Ever Happens, “the seal’s feces contain hundreds of tiny glassy-shelled eggs. They are ingested by various microscopic filter-feeders like our ubiquitous copepods. These are eaten by small fishes, which are eaten by bigger fishes, and so on. By the time the next seal eats the biggest fish in the food chain, the number of worms in the fish’s body is magnified…the seal gets a mouthful of juvenile worms.” The life cycle of Anisakis simplex continues to repeat after that, revolving between seal and fish.

The life cycle of the nematode presents a challenge for raw-fish enthusiasts. When the nematode finds its way onto a plate of sushi, and subsequently, into a human’s stomach, it will cause trouble. Fortunately, most of the time, the parasites, even if ingested, will pass through the human body without causing harm. Rarely will juveniles penetrate the stomach or intestinal wall, causing a deadly infection known as anisakiasis, a condition leading to appendicitis-like pain, and sometimes even death.

While anisakiasis is rare, it does happen, even with all the precautions taken with sushi-grade fish. Sushi-grade fish are treated differently from the raw fish sitting on ice one may find at the supermarket. Wild-catches are immediately gutted and flash-frozen to prevent bacteria from migrating into the meat if the fish is meant to be consumed raw. However, this along with other methods, are not enough to 100% ensure parasite-free meat.

Luckily, the chances are only 1:128,000 for contracting a serious infection.

Anisakiasis is frightening, but it has not been enough to curb my interest in seafood. Certainly, it is something that passes through my mind each time I take a bite at my favorite sushi restaurant. But is it really something to worry about it? In my opinion, not at all.

So go out and enjoy sushi, and stop worrying about the “what if.” You’ll enjoy life more.


Citation: Kaplan, Eugene H. “It Hardly Ever Happens.” What’s Eating You? Princeton: Princeton UP, 2010. 75-81. Print.

imagesAnisakis simplex


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