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Why You Should Never Eat Crayfish and Other Crustaceans Raw

Kristie Leong M.D. is a family practitioner who believes in the power of nutrition and a healthy lifestyle to prevent and fight illness.

Can you eat raw crayfish?

Can you eat raw crayfish?

Who can account for taste preferences? Some people find the taste of crayfish to be appealing – even when they eat them raw. Unfortunately, eating raw crayfish isn’t a smart idea from a health standpoint.

Every year, people and animals worldwide become ill from eating raw crayfish. Unlike many foods that cause illness, it’s not the crayfish itself but the tiny parasites they're exposed to that cause health issues. When this happens, people experience symptoms related to their respiratory system.

Raw Crayfish Can Harbor Parasites

Before eating raw crayfish, think and make sure you're doing it safely. These freshwater crustaceans resemble small lobsters and can harbor a parasite called Paragonimus kellicotti, also known as the lung fluke. Crayfish are omnivorous, meaning they will eat just about anything they can find. This can include other crayfish, insects, snails, and even fish.

More than 21 million people develop infections from Paragonimus kellicotti, mostly small animals, but also some humans. Infection is more common among people who live in Southeast Asia and China, where crayfish are considered a delicacy.

The Parasites in Crayfish Can Cause Lung Infections

When humans or animals eat raw crayfish infected with Paragonimus Kellicotti, the lung fluke enters the body through the digestive tract and moves to the lungs where it can cause a serious lung infection.

People who have this rare infection usually develop a cough, shortness of breath, difficulty breathing, fever, and fatigue. The symptoms of infection with the lung fluke can be severe in some cases. People infected with it can also develop fluid build-up around the lungs, a condition called pleural effusion.

Without treatment, lung flukes can cause persistent and even permanent lung damage. Rarely, the lung fluke migrates to the brain where it causes severe headaches and visual problems including temporary vision loss. But lung flukes have a propensity toward lung tissue and cause most of their damage there.

How Are Lung Flukes Treated?

Treatment for lung flukes is a drug called praziquantel. However, diagnosis can be challenging since most doctors don’t question people about whether they eat raw crayfish.

Therefore, the diagnosis is often missed or delayed. Without a high index of suspicion, the diagnosis can be quite challenging for healthcare providers. It’s also common for doctors to misdiagnose this condition as tuberculosis, another condition that affects the lungs. This can delay treatment and make the infection harder to eradicate.

Don’t Eat Raw Crayfish or Raw Crab

Raw crayfish aren’t the only source of lung fluke. Any raw crustacean can harbor Paragonimum kellicotti – particularly raw crab. That’s why it’s so important to thoroughly cook crustaceans to kill parasites. Keep raw crayfish away from furry friends too. Dogs, cats, and other mammals are susceptible to this rare infectious disease too.

An egg from a Lung Fluke Parasite

An egg from a Lung Fluke Parasite

Are There Benefits to Eating Crayfish?

If you cook crayfish thoroughly, they offer some nutritional benefits. Crayfish are a good source of protein and are low in fat. They are also rich in omega-3 fatty acids, healthy fats that are beneficial for heart health and help reduce inflammation. In addition, they contain a variety of vitamins and minerals. However, the risks of eating them raw outweigh the nutritional benefits.

Eat Crayfish Safely

If you eat crayfish and other crustaceans, do so safely by cooking them thoroughly before eating them. Crustaceans from polluted waters can be a source of other bacteria that cause food poisoning. Don’t eat them raw – and don’t let your pets have raw ones either. Keep food safety in mind when eating any kind of food.


  • Medical News Today website. "Dangerous Lung Worms Found In People Who Eat Raw Crayfish"
  • Fischer, Peter U.; Curtis, Kurt C.; Marcos, Luis A.; Weil, Gary J. (June 2011). "Molecular characterization of the North American lung fluke Paragonimus kellicotti in Missouri and its development in Mongolian gerbils". Am J Trop Med Hyg. 84 (6): 1005–11. doi:10.4269/ajtmh.2011.11-0027. PMC 3110363. PMID 21633042.
  • Baum, Stephen G. "Paragonimiasis -- Cook Those Crawdads!" Journal Watch. Infectious Diseases (2010): n. pag. ProQuest. Web. 12 Oct. 2013.
  • Johannesen E, Nguyen V. Paragonimus kellicotti: A Lung Infection in Our Own Backyard. Case Rep Pathol. 2016;2016:2107372. doi: 10.1155/2016/2107372. Epub 2016 Apr 24. PMID: 27213066; PMCID: PMC4860236.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.