Anisakiasis

Anisakiasis is an infection of the gastrointestinal tract by the round worms Anisakis simplex, Anisakis physeteris and Pseudoterranova. Infection occurs due to ingestion of raw or inadequately cooked fish, squid, octopus etc. It is characterized by crampy abdominal pain, nausea and vomiting.

Where does it occur?

It occurs in South East Asia (sashimi/sushi), Scandinavia (gravlax, smoked or pickled fish) and South America (ceviche)

How is it transmitted?

It is transmitted primarily by eating raw or undercooked fish.

Is it contagious from person to person?

It is not contagious from person to person.

What is the risk for travelers?

Generally the risk is very low, but increased in travelers to developing nations who eat raw fish and meat.

How soon after exposure will one develop symptoms?

Symptoms can occur within a few hours with stomach pains but large and small bowel symptoms may take 1-2 weeks to develop.

What are the signs and symptoms?

Symptoms include burning to sharp pain in the upper middle abdomen with nausea, indigestion and vomiting. As the larvae migrate up the esophagus it can cause one to occasionally cough it up. As the larvae migrate down the small and large intestines it can cause abscesses with localized pain that may resemble appendicitis or diverticulitis. Rarely there can be penetration of the bowel wall with generalized abdominal pain, fever etc.

Are there any lab tests to diagnose the illness?

Blood eosinophil count can be elevated, but diagnosis is made by observing the worm on endoscopy or surgical specimens.

Is there any treatment?

Treatment is removal of worm by endoscopy or surgical removal of abscesses containing the worm.

What preventive measures can be taken?

Avoid eating raw or undercooked fish.
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