DETECTION OF ANISAKIDS IN BALTIC FISH AND FISHERY PRODUCTS - PRELIMINARY RESULTS

Mirosław Różycki¹, Ewa Bilska - Zając¹, Maciej Kochanowski¹, Ewa Chmurzyńska¹, Katarzyna Nadolna - Ałtyn², Magdalena Podolska²,Tomasz Cencek¹
1- Department of Parasitology and Invasive Diseases, National Veterinary Research Institute, Al. Partyzantow 57, 24 100 Pulawy, Poland
2- Department of Fisheries Resources, National Marine Fisheries Research Institute ul. Kollataja 1, 81-332 Gdynia, Poland

In the last decades public health authorities have detected a relevant increase of seafood-borne diseases. The most hazardous helminths for human health, originated from marine fish, are anisakid nematodes. Human diseases are either caused by ingestion of viable parasites, or as an allergenic reaction. The symptoms of this disease include abdominal pain, vomiting, nausea and diarrhea. Diagnosis of anisakidosis is mainly based on endoscopy. In case of ulcerosis and necrosis of stomach wall chirurgical excision may be necessary. As there is a lack of sufficient data on the geographical distribution, prevalence and intensity of parasites of public health importance in fishery products, all wild-catch products are considered at risk of containing parasites. Parasites can affect the commercial value of fish and thus result in significant economic losses. Fish caught from fishing grounds in the Baltic Sea, may present possible health risks from: Anisakis simplex (sensu stricto), Contracaecum osculatum (sensu stricto), Pseudoterranova decipiens (sensu stricto). The A. simplex and Pseudoterranova decipiens have been found in fishery products in International Council for the Exploration of the Sea (ICES) subdivisions 22, 23, 24, 25, 26, thus the public health risks due to the presence of these parasites cannot be excluded. Part of the SeaQual project is devoted to assess the presence of Anisakids in fish from Baltic Sea. The aim of the carried study is to collect the data on the presence of parasites in wild caught fish from the Baltic Sea for further risk assessment. For the study herring (Clupea herrengus) and cod (Gadus morhua) caught in the Baltic Sea were examined. Samples were collected from the sea catch provided in April 2016 by the research vessel "Baltica" (fig.1). Totally 246 herring and 228 cod samples were collected. Fish samples were examined by candling method, candling with UV and digestion of muscle tissue (fig.2). All the methods were validated; candling and digestion were accredited by the Polish Centre for Accreditation. Overall, 14.23% of herring and 9.65% of cod were found to be positive with the use of digestion method. The prevalence in herrings varied from 2.35% (ICES 25) up to, 23% (ICES 26). For cod varied from 6% (ICES 24) up to 15% (ICES 25). From cod muscle as Anisakis simplex s.s. 20 larvae were identified and 2 larvae were classified as P. decipiens. Larvae originated from herring were identified as Anisakis simplex s.s. in 30 cases, and 5 larvae were classified as P. decipiens. Species of anisakids were identified by PCR-RFLP. As the result of the study guideline for parasitological examination of fish for Veterinary Service was elaborated. Research was supported by NCBiR under the Strategic Program Biostrateg (grant no.296211/4/NCBR/2016)