CRASSICAUDOSIS IN FIN WHALES (BALAENOPTERA PHYSALUS) STRANDED ALONG ITALIAN COASTS

Of several known crassicaudid infections, those caused by Crassicauda boopis (Nematoda, Spirurida) in whale are especially pathogenic. The giant adult nematode grows in the vascular and ureteral system of the kidney; it can cause complete vascular occlusion and kidney failure as described in Atlantic fin whales, Balaenoptera physalus; no data are still available in literature for this host species in Mediterranean basin. Six fin whales, stranded dead along Italian coastline in the period 2006-2013, were analyzed for Crassicauda infection. The parasites were morphologically identified according to Lambertsen (1985); molecular analyses by amplification and sequencing of a portion of the 18S of the small subunit ribosomal and internal transcribed spacers 2 (ITS2) of the rRNA were carried out. Formalin-fixed tissues were routinely processed for histology. Crassicaudosis was observed in four out six examined animals. Adult C. boopis were found in three fin whales, one of which had also nematode larvae in intestinal nodules and mesenteric vessels’ wall. Another animal showed vascular lesions with ruined fragments of the nematode inside. The sequences obtained from the parasitic elements (adults, larvae and lesions) showed a high identity with each other for ITS2 region; the 18S sequences had high identity with the unique Crassicauda sequence (C. magna) registered in GenBank (Accession number: KM233410.1). Chronic vasculitis and/or thrombosis were observed in renal vessels, vena cava and mesenteric arteries, leading to almost complete occlusion of vessels lumen in three cases. Histology showed renal fibrosis, perirenal granulomas and disseminated Crassicauda eggs in renal vessels, renal pelvis and adrenal glands. This study provides data on the presence, pathology and biomolecular characterization of C. boopis in fin whale of the Mediterranean Sea.