Inter-Research > DAO > v132 > n2 > p125-134  
Diseases of Aquatic Organisms

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DAO 132:125-134 (2019)  -  DOI:

Morphological and molecular identification of a new Kudoa thyrsites isolate in Mediterranean silver scabbardfish Lepidopus caudatus

Lucilla Giulietti1,*, Simonetta Mattiucci2, Michela Paoletti3, Didrik H. Grevskott1, Miguel Bao1, Paolo Cipriani1, Arne Levsen1

1Institute of Marine Research (IMR), Nordnes, Bergen 5009, Norway
2Department of Public Health and Infectious Diseases, Section of Parasitology, Sapienza-University of Rome 00185, Italy
3Department of Ecological and Biological Sciences, Tuscia University, Viterbo 01100, Italy
*Corresponding author:

ABSTRACT: Myxozoans of the genus Kudoa (Myxosporea, Multivalvulida) infect marine and estuarine fish species worldwide. Some Kudoa species are of concern to the seafood industry since they may generate macroscopic cysts in the fish host’s musculature, or cause post mortem myoliquefaction, commonly known as ‘soft flesh’. One of the economically most important species is K. thyrsites, a myoliquefactive myxosporean parasite that occurs in many wild and cultured marine fish species worldwide. Here we identified a K. thyrsites isolate as the causative agent of myoliquefaction in silver scabbardfish Lepidopus caudatus from the Alboran Sea (western Mediterranean Sea). For comparative and validation purposes, the morphological and molecular characteristics of the isolate were compared with fresh spores of a K. thyrsites isolate infecting Atlantic mackerel Scomber scombrus from the Norwegian Sea. Myxospores of both isolates shared a stellate appearance and contained 4 unequal pyriform polar capsules (1 large, 1 small and 2 intermediate). These morphological traits were consistent with all other previously described K. thyrsites isolates. Moreover, the small subunit rDNA sequences of the Mediterranean and Norwegian Sea isolates revealed 100% similarity, and matched 100% with K. thyrsites isolates previously recorded in myoliquefactive Atlantic mackerel from the North Sea and off southern England. The findings suggest that K. thyrsites is the primary cause of myoliquefaction in silver scabbardfish from the Alboran Sea. This report represents the first morphological and molecular characterization of K. thyrsites in the Mediterranean Sea. A set of new allometric characters is proposed as additional descriptors for more accurate and specific description of kudoid myxospores.

KEY WORDS: Kudoa thyrsites · Mediterranean Sea · ‘Soft flesh’ · Myoliquefaction · Lepidopus caudatus · Molecular identification · New morphological characters · Fish parasite

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Cite this article as: Giulietti L, Mattiucci S, Paoletti M, Grevskott DH, Bao M, Cipriani P, Levsen A (2019) Morphological and molecular identification of a new Kudoa thyrsites isolate in Mediterranean silver scabbardfish Lepidopus caudatus. Dis Aquat Org 132:125-134.

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