Raw Fish Sashimi & Sushi: Will it Give You Tapeworms?

So recently there’s been an infestation of scary tapeworm articles on Facebook which almost turned us off raw fish forever. According to The Daily Mail, some guy in China went to his doctor with a stomach ache and itchy skin, and upon further investigation found his entire body infected with tapeworm.

Here’s a pic of what they found on the X-ray (warning: gross image coming up):

Source: dailymail.co.uk
Looks like a scene plucked out from a horror movie, eh? | Source: dailymail.co.uk

As a sushi lover, I’ve always understood the risks of eating raw fish, especially if it wasn’t fresh or stored well, but I wasn’t willing to give up delicious juicy bites of sashimi just because one guy ate bad sushi.

Instead, I decided to do some research about how this occured, and how best to avoid it.

After digging around, I realised that the article was in fact, inaccurate. According to several experts, this kind of infestation simply wasn’t possible with raw fish.

Here’s the Low Down on the Alleged Tapeworm Infestation

While there’s a definite risk of parasitic infection when eating raw fish, the photos used in the report by The Daily Mail was actually part of a case report published by the British Medical Journal [1].

The x-ray showed a 74-year old patient who suffered from disseminated cysticercosis, which is a rare form of cysticercosis where the larvae of certain tapeworms are spread throughout the body [2].

Source: wikipedia.org
Source: wikipedia.org

When he started suffering from walking abnormalities, memory loss, and disturbance of consciousness, he was admitted to the emergency department where doctors found his body riddled with these tapeworm babies.

And the interesting part of the story is that he got this tapeworm infestation not from raw fish, but from uncooked pork tainted with pork tapeworm larvae. The pork tapeworm larvae is an entirely different species than those in fish.

But is it Really Safe to Eat Raw Fish? 

Source: reddit.com
Source: reddit.com

It depends on where the fish comes from.

Most sushi and sashimi in traditional Japanese restaurants are made from marine fish like tuna, yellow tail, red snapper, salmon, and flatfish, which are usually parasite-free. (Read: safe to eat)

Of these fishes, salmon is the most probable host for a fish tapeworm called Diphyllobothrium latum. Some marine fish could be home to the Anisakis larvae, but these fishes are less commonly found served raw in Japanese restaurants (cod, herring, mackerel, squid etc).

Freshwater or brackish water fish however, are large hosts of parasites so you should avoid eating those raw [3].

Know Your Worms

The Anisakis parasite (herring worm)

Source: cdc.gov
Source: cdc.gov
  • Where is it: This little guy lives in the muscles and visceral organs of fish.
  • How you get infected: By eating raw or undercooked fish already infected with anisakis.
  • What happens: The larvae usually penetrates the gastric wall to cause you abdominal pain, nausea, and vomiting.
  • When do symptoms appear: Within minutes to hours from eating
  • How it’s diagnosed: Upper gastrointestinal endoscopic exam
  • How it’s treated: This worm cannot survive in humans and will die within a few weeks. Depending on your situation, a drug or an endoscopic exam could kill off / remove the worm.

The Diphyllobothrium latum parasite (fish tapeworm)

Source: cdc.gov
Source: cdc.gov
  • Where is it: They reside in the muscles of trout, salmon, pike, and sea bass.
  • How you get infected: By eating raw or undercooked fish already infected with d.latum.
  • What happens: It attaches to your small intestine and grow to become adult worms of about 5-10m (scary!), and its tail could sometimes pop out of your anus (even more scary!). D.latum sheds plenty of eggs daily, and these end up in your poo.
  • When do symptoms appear: Most people show no signs of infection, though a few experience vomiting, diarrhoea, and weight loss. This worm absorbs up to 80% of vitamin B-12 from your body, so in prolonged cases, you could suffer from severe vitamin B-12 deficiency.
  • How it’s diagnosed: There are a few ways to go about this. (i) through a stool sample, (ii) a routine colonoscopy, (iii) a PCR test
  • How it’s treated: This part is easy. You’ll be given a drug to get rid of the worms.

[Sources: 456]

To Eat or Not to Eat? 

Source: buzzfeed.com
Source: buzzfeed.com

According to the experts, it’s pretty rare for marine fish used in sushi restaurants to harbour these horrid parasites. Yay sushi, we’re coming for you again!

However, you still have to watch your back and choose reputable establishments that store their fish at the regulated temperatures. And stay away from ethnic sashimi made from wild boar, backyard chicken, and other things you wouldn’t normally touch with a ten foot pole.

fish oil


Will you continue eating sashimi & sushi? Let’s talk about it in the comments section below or on our Facebook page


2 thoughts on “Raw Fish Sashimi & Sushi: Will it Give You Tapeworms?”

  1. Cat

    Thanks for this informational article! I’m definitely going to eat sushi tonight! 😀

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