engleski

Molecular identification of Anisakis spp. complex from gastrointestinal tract of stranded cetaceans in adriatic Sea

There is a general lack of data concerning cetacean ecology in the Adriatic Sea, moreover on migrational patterns, feeding habits and health, thus any information that might contribute to clarification of such mechanisms is important. Parasites have been considered as good biomarkers in revealing their host history, reflecting their natural ecological relationships and possibly enabling tracing of host migrational patterns. Marine mammals serve as a definitive host in lifecycle of Anisakid species, representing the only source where the parasite matures to the adult stage and reproduces. Available information indicates that as a probable result of co evolution, cetacean-Anisakis relationship is species specific. The lack of firm morphological features differentiating between members of genus Anisakis, makes molecular identification the only tool of choice for their identification. Parasites showing morphological features consistent with genus Anisakis were collected from gastric compartments of eighteen cetacean carcasses belonging to three species (Ziphius cavirostris, Stenella coeruleoalba and Tursiops truncatus), found along Croatian coastline from 2004 to 2011. In detecting possible mixed infection at least 10 parasites per dolphin were analysed by molecular identification of mtDNA. In total, DNA was isolated from 96 samples preserved in ethanol and 2 fixed in formalin, and PCR reaction amplified 500 bp fragment of COXII gene using published primers and protocol. BLAST analyses with homologous sequences in GenBank indicated the presence of three different Anisakis species in stranded cetaceans of the Adriatic Sea: Anisakis pegreffi, Anisakis simplex and Anisakis physeteris. This represents an important first geographical report of the last two species, previously recorded only in the west Mediterranean and Atlantic. Anisakis pegreffi showed the highest prevalence (94.9 %) which is in accordance with occurrence of its preferred host, bottlenose dolphin, in Adriatic. The finding of new Anisakis spp. in this area might elucidate migrational patterns of their cetacean hosts.

Anisakis pegreffii; cetacea; Adriatic Sea

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