Anisakis LifecycleAnisakis


The marine roundworms (nematodes), Anisakis and Pseudoterranova species, have marine mammals and fish eating birds as final hosts, crustaceans as first intermediate host and cephalopods and saltwater fish as second intermediate hosts or paratenic hosts.

When people consume infected raw or undercooked intermediate hosts they can become accidental hosts. This can (not always) cause clinical symptoms going from mild to severe abdominal complaints and allergic reactions. The latter are caused by specific allergenic worm proteins, of which some seem to be freeze and heat resistant (Nieuwenhuizen & Lopata, 2013).

High prevalences of anisakidae have been detected in most commercial fish species (for some fish species close to 100%), with a cosmopolitan distribution (Pozio, 2013). An increased occurrence in fish and in human cases has been observed in the last decades, probably due to an increase in occurrence of marine mammals (final hosts), increase in fish consumption, increase in raw fish consumption (imported traditional dishes), but also due to an increased attention of stakeholders and improved (use of) diagnostic tools.

Besides being a public health problem, the high occurrence of viable worms in fish has led to a high number of customers complaints which in turn has a big economic impact on the fish industry (Pozio, 2013). The sector is obliged to inspect all fish for the presence of these roundworms and remove as many as possible manually. This entails a huge labour cost, and is inefficient. Even when applying these techniques, many fish fillets arrive at the consumer with viable worms, thus not eliminating the public health risk and consumers complaints.

The laboratory of foodborne parasitic zoonoses studies the occurrence of these parasites in Belgium, their impact on the fish industry, and looks into more rapid diagnostics and methods to remove larvae from the fish fillets. Additionally the laboratory studies bacterial and allergic concerns related to these parasites.

Parts of this research is done in collaboration with the Laboratory of Microbiology and the Faculty of Bioscience Engineering, Department of Food Technology, Safety and Health.


This research is conducted in the framework of three PhD projects:

  • Evelien Mercken
  • Aiyan Guan
  • Ganna Saelens