Aside from parasites, raw fish and shellfish can contain a variety of toxins that can cause gastrointestinal distress.
The Lisbon doctors who treated the man are now warning other doctors to consider diagnosing the condition to patients suffering, pain, vomiting, nausea and other complications like bowel obstruction and bleeding if they have recently eaten sushi. Doctors performed blood tests which revealed he had high presence of white blood cells, which is an indication of infection.
The Italian study added that medical professionals should be suspected of the case, patients must complain of severe abdominal pain after eating raw fish, pointing out that "no effective drug treatment is capable of killing larvae once eaten".
"The patient's symptoms resolved immediately", the medics wrote.
Infections like this are mostly seen in Asia where consuming raw fish is more common.
According to the British Medical Journal, parasitic infections are on the rise, and it's probably because we can't seem to stop stuffing our faces with sushi. According to them, sushi may pose a serious health hazard as it has parasites present in undercooked fish and seafood. So maybe the next time you're craving a slice of sashimi you better head to the river and catch your own.
Anisakiasis is a zoonotic disease caused when people consume raw or undercooked fish or seafood that is contaminated by the nematodes parasites of the genus Anisakis. According to CNN, the anisakis is a parasitic worm that lives in mackerel, squids, salmon, herring, cod, red snapper, and halibut. Laboratory analysis showed that the larva belonged to the anisakis species.
Since then, cases have appeared in many other countries, though "mainly in Japan because of the frequent ingestion of raw fish", Carmo said.
Yet recent estimates suggest that about 8,000 annual anisakiasis cases may be occurring in Spain due to consumption of raw and marinated anchovies, Bao said.
So, only cases where the parasite actually embeds in the stomach or intestine wall may actually come to light, he explained. In such cases, it is possible to cough up the worm or remove it by hand.
Raw or undercooked fish poses a risk of food poisoning if it is not prepared properly. "They're not cooking the fish so that is the only prevention method, keeping it cold", he said. The FDA says freezing fish can kill parasites, too.