Infectious Diseases Associated With Eating Sushi and Sashimi

Sushi is a traditional Japanese food and a favorite for many in the United States. Sashimi, which is thinly sliced raw fish often served with sauces (like wasabi or soy sauce), is another popular delicacy. 

Unlike sashimi, sushi does not necessarily involve raw fish. In fact, sushi simply refers to the small balls or rolls of vinegar-flavored cooked rice. These rice rolls are then wrapped in seaweed and garnished with vegetables, egg, raw fish, cooked fish, or other foods.

That said, when enjoying sashimi or sushi that contains raw fish, it's important to be aware of the health risks. These can include consuming disease-causing bacteria or parasites.

This article discusses the types of infectious diseases that could occur from eating raw fish in sashimi or sushi. It also covers symptoms to watch for and who is most at-risk.

Anisakiasis

Human infection by Anisakiasis (herring worm) and other nematodes, or roundworms, can be caused by eating certain raw or undercooked fish.

Ingestion of this tiny worm can result in severe abdominal pain, nausea, and vomiting within hours of eating. Even more, if the worms don’t get coughed up or vomited out, they can burrow into the walls of your intestines. This can cause a localized immune response, or inflammation, in the intestine.

If this does occur, the worms eventually die and are removed by the immune system. However, in severe cases, your doctor may need to remove them to reduce the pain. This could be done by surgery or by endoscopy, a flexible tube and camera that allows the doctor to see and remove them.

Vibrio

The bacterial species Vibrio parahaemolyticus is associated with eating raw or undercooked fish and shellfish, particularly oysters.

Infection can cause symptoms like diarrhea (including bloody diarrhea), abdominal cramps, nausea, vomiting, headache, fever, and chills. It can become severe in people with weakened immune systems. 

Another Vibrio species, Vibrio vulnificus, has been found in oysters, clams, and crab. In healthy people, ingestion of this microbe may cause nausea, vomiting, watery diarrhea, abdominal cramps, and fever.

In people with liver disease or weakened immune systems, the microbe can enter the bloodstream, causing a life-threatening whole-body infection. 

In addition, the Vibrio species can cause wound infections through open sores exposed to water harboring the bacteria. Examples include scrapes when opening oysters or working on boats. Like the gastrointestinal illness, these types of wound infections are most severe in people with impaired immune systems.

Listeriosis

Listeriosis is an infection caused by the bacteria Listeria monocytogenes. This bacteria can be found in raw seafood, unpasteurized milk and dairy products, vegetables such as raw sprouts, and other foods.

The biggest risk for listeriosis is in people who are:

• Pregnant
• Newborns (the bacteria can pass through the placenta)
• Older than age 65
• Have a weakened immune system

If listeria spreads to infect the nervous system, it can lead to meningitis, which is inflammation of the membranes and fluid around the brain and spinal cord.

It could also cause meningoencephalitis—inflammation of both the brain tissue and the membranes around the brain. Nervous system infection is most common in the immunocompromised and the elderly.

If you're not pregnant, listeriosis may cause mild symptoms like fever and diarrhea. It can also cause severe symptoms, like stiff neck and confusion, if the infection has spread to the nervous system. If you are pregnant, listeriosis may lead to a miscarriage, stillbirth, premature delivery, or a serious infection in the newborn.

Salmonella

Salmonella infection causes symptoms of diarrhea, fever, and stomach cramps. Symptoms often begin within one to three days of eating the contaminated food. Infants, those with low immune function, and people over 65 are most at risk of developing a severe illness requiring hospitalization.

Bacillus Cereus

Bacillus cereus is another foodborne illness associated with eating sushi. It's linked to eating contaminated rice along with other foods like fish, vegetables, meats, and milk.

There are two types of Bacillus cereus infections: a diarrheal type and a vomiting type. The vomiting type is associated with contaminated rice products. One example might be fried rice that has been sitting at room temperature for a long period.  

Contaminated Food Handlers

If food handlers do not use good hand hygiene, other infections (like norovirus, hepatitis A, and Staphylococcus aureus) can spread. Those who handle food should always wash their hands properly and stay home from work if ill.

Summary

It's possible to get an infectious disease when eating raw fish in sushi or sashimi. These could be caused by a worm, like anisakiasis, or a bacteria, such as Salmonella or listeriosis.

Many of these infections can cause digestive symptoms, including diarrhea, nausea, and vomiting. In some cases, they can lead to more serious conditions that require hospitalization.

A Word From Verywell

Inquiring about the practices and guidelines used to prepare your food is never a bad idea. And if your gut instinct is that something is not right, follow it.

Talk to your healthcare provider if you are worried about your personal risk. Contact them if you think you may have developed an infection from eating sushi or sashimi.

Otherwise, if you are healthy and know your food is from a reputable source, you can enjoy this Japanese, nutrient-rich delight.