Initial Evidence That Gilthead Seabream (Sparus aurata L.) Is a Host for Lymphocystis Disease Virus Genotype I

Abstract

Marine and brackish water aquacultures are rapidly expanding in the Mediterranean basin. In this context, Egypt recently received a shipment of a 1.5 million juvenile gilthead seabream (Sparus aurata L.) from European Mediterranean facility. Within a few weeks of their arrival, 95% of the imported fish developed nodules on their skin and fins that lasted for several months. This study was undertaken to describe the clinical disease course, to identify the causative agent, and to investigate its origin. Preliminary diagnosis based on gross lesions and postmortem examination suggested lymphocystis disease (LCD), caused by the lymphocystis disease virus (LCDV; genus Lymphocystivirus, family Iridoviridae). Histopathological and ultrastructural features were typical of LCDV infections. PCR followed by sequencing and phylogenetic analysis of a 306-bp fragment of the major capsid protein (MCP) gene demonstrated the presence of LCDV genotype I, originally associated with LCD in Northern European countries, with 99.7% and 100% nucleotide and deduced amino acid identity values, respectively. LCDV genotype I has neither been reported in this species nor in the region. Regardless of the source of infection, findings of this study add to existing knowledge about the ecology of LCDV genotype I and its host range.

Advances in Viral Aquatic Animal Disease Knowledge: The Molecular Methods’ Contribution

“…Moreover, the sequencing and phylogenetic analysis of a 306-bp fragment of the MCP gene of an isolate detected in juvenile gilthead seabream, imported from a Mediterranean hatchery to a farm in Egypt, demonstrated the presence of LCDV1, originally associated with lymphocystis disease in Northern European countries, expanding de facto both the host and the geographical range of this virus species [ 32 ].…”

Immune response of DNA vaccinated-gilthead seabream (Sparus aurata) against LCDV-Sa infection: relevance of the inflammatory process

“…This viral disease affects a wide variety of freshwater, brackish, and marine fish species, with Lymphocystis disease virus 3 (LCDV-3, also named LCDV-Sa) being the main causative agent of LCD in gilthead seabream ( Sparus aurata ), and Senegalese sole ( Solea senegalensis ) in the Mediterranean and European South-Atlantic marine aquaculture ( 4 – 7 ). That said, recently LCDV belonging to genotype I, associated with LCD in Northern European countries, has also been reported to affect this fish species in Egypt ( 8 ). LCD lesions usually resolve one month after their appearance and are significantly influenced by water temperature.…”