Parasites of Public Health Concern (Anisakis)

Anisakis and related marine zoonotic parasites are nematode worms whose larvae encyst in the flesh and viscera of fish and squid, and which cause anisakidosis, a gastrointestinal or allergic illness in humans who eat live larvae in raw or undercooked seafood. Wild pelagic fish such as herring, mackerel, anchovy, and blue whiting carry larvae acquired from eating infected crustaceans, while farmed salmon and sea bass have very low prevalence because controlled feed and life cycle break transmission, a strong marketing argument for aquaculture. The human hazard is killed by thorough cooking, freezing at minus 20 degrees Celsius for at least 24 hours or minus 35 degrees Celsius for 15 hours in commercial practice, or validated high-pressure treatment; visual inspection and candling remove visible larvae but are not considered sufficient alone for high-risk product. Regulatory frameworks including EU Regulation 1276/2011 mandate freezing treatment for fish destined to be eaten raw or cold-smoked. Symptoms range from acute epigastric pain and nausea within hours to chronic allergic reactions, and larval antigen can trigger severe IgE-mediated allergy even after the worm is killed. For farmers and processors, control means sourcing-screening wild raw material, documenting freezing treatments, and candling and trimming lines, because a single larva in a sushi product creates illness, recall, and reputational damage disproportionate to its size.