The Mediterranean Mussel (Mytilus galloprovincialis) as Intermediate Host for the Anisakid Sulcascaris sulcata (Nematoda), a Pathogen Parasite of the Mediterranean Loggerhead Turtle (Caretta caretta).

Mario Santoro,Federica Marcer,Erica Marchiori,Marialetizia Palomba,Simonetta Mattiucci,Barbara Degli Uberti

doi:10.3390/pathogens9020118

Abstract

Sulcascaris sulcata (Anisakidae), a pathogenic nematode of sea turtles, may cause ulcerous gastritis with different degrees of severity. Previous studies demonstrated a high prevalence of infection in the Mediterranean loggerhead turtle (Caretta caretta), although no data on the potential intermediate hosts of this nematode has been published thus far from the Mediterranean basin. Here, using molecular analyses, we demonstrated that the cross sections of nematode larvae observed histologically in Mediterranean mussels (Mytilus galloprovincialis) collected from a farm along the Tyrrhenian coast of southern Italy belong to S. sulcata. The BLAST analysis of sequences at the ITS2 region of rDNA and mtDNA cox2 gene loci here obtained from samples of two Mediterranean mussels containing nematode larvae showed 100% homology with those at the same gene loci from the adults of S. sulcata collected from the Mediterranean Sea and deposited in GenBank. To our knowledge, this study is the first to present data on a potential intermediate host of S. sulcata in the Mediterranean basin and to report a nematode parasite from the Mediterranean mussel.

Highlights

The anisakid nematode Sulcascaris sulcata is a pathogenic parasite of the esophagus and stomach of sea turtles being able to cause ulcerous gastritis with different degrees of severity predominantly depending on the intensity of infection
Berry and Cannon [2] demonstrated experimentally that hatchling loggerhead turtles become infected by ingesting scallops infected with fourth stage larvae S. sulcata
A total of five (1.4%) individual Mediterranean mussels collected on February, May, July, and August were histologically positive to one (n = 3), two (n = 1), and three (n = 1) cross sections of nematode larvae, respectively

Summary

Introduction

The anisakid nematode Sulcascaris sulcata is a pathogenic parasite of the esophagus and stomach of sea turtles being able to cause ulcerous gastritis with different degrees of severity predominantly depending on the intensity of infection. Berry and Cannon [2] demonstrated experimentally that hatchling loggerhead turtles become infected by ingesting scallops infected with fourth stage larvae S. sulcata. Larvae attach at the base of the esophagus where four molts occur about three weeks after infection and mature to adults in at least 5 months. Adult parasites live in the stomach of sea turtles and eggs are shed in the marine. Two molts occur in the egg until the development of the third stage larva, which spontaneously hatches and develops in bivalve and gastropod mollusks to fourth stage larva after 3–4 months. The duration of the natural cycle could be of two years [2]

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Conclusion