Scientific Opinion on risk assessment of parasites in fishery products

Abstract

Human fishery product‐borne parasitic diseases are caused by cestodes, trematodes and nematodes and are caused by infection following ingestion of viable parasites, or as allergic (hypersensitivity) reactions against parasite antigens. For allergy, the only parasite in fishery products implicated is the nematode Anisakis simplex, and sensitisation occurs via infection by live larvae. Once sensitised, response to nematode allergens can be highly aggressive and generate severe disease. In a sensitised individual, infection can provoke a concurrent A. simplex allergic episode or can be elicited by exposure to allergen alone from killed parasite: the relative epidemiological impact for each is unknown. Allergy to A. simplex is relatively common in some regions in Spain but rarely reported in other parts of Europe. Prevention of sensitisation is most likely to be effective by control of A. simplex infection. There is more information on the resistance to physical and chemical treatments by A. simplex than for other fishery parasites, and the properties of other parasites are likely to be similar. Many traditional marinating and cold smoking methods are not sufficient to kill A. simplex and freezing or heat treatments remain the most effective processes guaranteeing killing. All wild caught seawater and freshwater fish are must be considered at risk of containing any viable parasites of human health concern if these products are to be eaten raw or almost raw. For wild‐catch fish, no sea fishing grounds can be considered free of A. simplex. For farmed Atlantic salmon reared in floating cages or onshore tanks and fed on compound feedstuffs however, the current risk of infection with anisakids is negligible. Apart from farmed Atlantic salmon, sufficient monitoring data are not available for any other farmed fish therefore it is not possible to identify which fish species do not present a health hazard with respect to the presence of parasites.

Ecology and Genetic Structure of Zoonotic Anisakis spp. from Adriatic Commercial Fish Species

“…In contrast, the normal distribution of aggregating larvae was observed in chub mackerel, possibly associated with the limited life span of the parasite and the robustness of the host immune response at a specific length/age (49). We also confirmed the tendency of Anisakis larvae toward a particular organ in a specific host (2,43,44,49), which has been related to the availability of nutrients to the parasite (2), although firm evidence has never been provided. We argue that an anatomical relationship between the point of anisakid penetration through the gastrointestinal tract (related to intrinsic host factors, such as gut peristalsis or the quantity of its content) and the location of the visceral organ that is close to that point governs the predilection site in the host.…”

“…We observed a significant difference in the numbers of parasite larvae (1 to 32) in individual hosts and between species, as described previously (2,23), which underscores the necessity to monitor anisakid infections over a longer time span in order to develop an adequate risk assessment analysis for commercially important fish. Interestingly, the aggregation of the parasite varies with the host species.…”

“…Consequently, health authorities and the fishing industry have become aware of the significance of the nematode genus Anisakis Dujardin, 1845, whose members affect both human health and the commercial value of fish products. Although it is considered one of the most significant emerging food-borne zoonoses, anisakiasis in many countries is still misdiagnosed or underestimated (2).…”

Methods for Anisakis simplex detection in fish and fishery productsMethods for Anisakis simplex detection in fish and fishery products

“…Należy podkreślić, że reakcje alergiczne mogą wystąpić również w przypadku spożycia przetworzonych produktów rybnych, w których stwierdza się obecność alergenów Anisakis (2,9). Do 2010 r. na świecie zarejestrowano ponad 20 000 przypadków anisakiozy u ludzi (18). Rocznie notuje się około 2000 nowych przypadków (33).…”

Allergenic activity of Pseudoterranova decipiens (Nematoda: Anisakidae) in BALB/c mice

“…So far, Anisakis simplex (sensu lato ), i.e. Anisakis simplex (sensu stricto), Anisakis pegreffii and Anisakis berlandi are the only fishery-product associated parasites causing clinical allergic responses recognized by EFSA [9]. In fact, A. simplex ( s.l. )…”