Gene expression of parasitic Pseudoterranova bulbosa (Nematoda) in different tissues of its intermediate host, Atlantic cod (Gadus morhua)

Parasitic Nematoda from the Pseudoterranova decipiens complex (Ascaridoidea, Anisakidae) are common parasites of marine demersal fishes from temperate to polar regions. Their life cycles include a free larval stage, first obligatory invertebrate host, paratenic fish hosts and a species specific definitive host (Pinnipedia). Due to their human-pathogenic potential and their occurrence in food fish, e.g. Atlantic cod (Gadus morhua), Pseudoterranova spp. are relevant for food safety. The liver of the fish host is often observed as the site with the highest infection intensity. The mechanism for site preference has not yet been understood.Parasite samples of Pseudoterranova bulbosa from the liver and viscera of cod were taken during the 431. cruise of the research vessel Walther Herwig III, off the coast of Greenland. Samples were barcoded using PCR amplification of cytochrome oxidase subunit I. To reduce the influence of population specific differences we genotyped the samples using the ribosomal internal transcribed spacers and selected samples with the same genotype. A de novo transcriptome was built and gene expression patterns were compared between the infected tissues.