Anisakid Nematodes and Potential Risk of Human Anisakiasis through the Consumption of Hake, Merluccius spp., Sold Fresh in Spanish Supermarkets

Abstract

Nematode parasite species belonging to the Anisakis simplex complex are the most important cause of human anisakiasis through the consumption of (mainly) undercooked, previously not frozen, or conveniently treated fish. In Spain, the consumption of hake has been recognized as an important source of this parasitosis. With the aim of shedding light on the risk factors that can influence the potential risk of human anisakiasis in Spain through the consumption of fresh hake sold by nationwide supermarket chains, a total of 536 small hake specimens belonging to the species Merluccius bilinearis caught off the Northeast American coasts and Merluccius merluccius caught in the Northeast Atlantic and Mediterranean waters was analysed. Anisakids morphologically identified as Anisakis type I were found as the most prevalent and the most abundant species and were considered the main potential cause of human anisakiasis. Intrinsic and extrinsic factors concerning the hake, such as its origin and season of capture, its size, as well as the days passed between its capture and consumption, should be taken into account to avoid this human parasitosis. It is essential that consumers have access to fish label information which should include, as regulated by the European Commission, traceability data.

Nematode Parasites of the European Pilchard, Sardina pilchardus (Walbaum, 1792): A Genuine Human Hazard?

“…The influence of the fish size (length and weight) has previously been reported in the sardine [ 5 , 24 , 29 , 41 ] as well as in other fish species, showing that the youngest sardines, less parasitized, preferably feed on phytoplankton [ 46 ], and the older ones, more parasitized, have changed their feeding habits and also accumulate parasites throughout their lives. On the other hand, the generally lower rate of migration of larvae to the flesh will explain the lack of correlation between this parameter with the number of days passed since the capture of the fish until their analysis (potential consumption), contrary to what has been demonstrated in other fish species such as the blue whiting [ 25 , 51 ], the mackerel [ 25 , 52 ] and the European hake [ 25 , 53 ]. Another explanation could be that, as suggested in other previous studies in the European pilchard [ 29 ] and anchovy [ 54 ], larvae migrate to the flesh even intra vitam, and consequently, the days passed before consumption may not be as decisive in larval migration in the case of sardines.…”

Anisakiasis and Anisakidae

“…In this Special Issue of Pathogens , 12 articles have been collected, among which those dedicated to food safety (six papers) predominate. These articles focus on the study of the presence of anisakids in various marine fish of commercial interest, such as Merluccius spp., Conger conger or Mullus barbatus , flatfish such as Dicologlossa cuneata and Citharus linguatula , and freshwater fish such as the Prussian carp ( Carassius gibelio ) [ 19 , 20 , 21 , 22 , 23 , 24 ].…”