Lymphocystosis (Lymphocystis Disease virus -LCDV-): Molecular diagnosis (PCR).

The virus causing the lymphocystosis (Lymphocystis Disease virus) has a worldwide distribution, causing a chronic benign disease, nonfatal, in many teleosts and affects at least 125 different species of fish belonging to about 42 families, including marine and both wild as crops (aquaculture) and ornamentals. freshwaters

This virus belongs to the family Iridoviridae genus Lymphocystivirus, including viruses with genome linear double stranded DNA (dsDNA) and icosahedral nucleocapsid about 200 ± 50 nm in diameter, with a capsid double layer, and an outer envelope and a strip of fibrillar external protrusions.

3 genotypes are currently supported:

Genotype I, corresponding to the virus causing lymphocystosis (LCDV), such as affecting seabass (Lateobrax spp.).

Genotype II, which would include viruses isolated from Japanese Flounder (Japanese Flounder) (Paralichthys olivaceous).

Genotype III, for isolated rock fish (Rockfish) (Sebastes schlegeli).

Lymphocystosis is a chronic benign disease, manifested in fish affected by clusters of very hypertrophied dermal cells in the skin and fins. The mortality rate of infected fish is low, but fish disfigurement makes them unusable. These cells are referred to as hypertrophied cells lymphocystosis and have a thick hyaline capsule and a hypertrophied nucleus with basophilic intranuclear inclusions.

Recommended diagnostic methods

Various methods have been used as insulation in susceptible cell cultures, which have the difficulty that there is little susceptible cell lines and require subsequent identification by virus neutralization tests.

Today, the recommended methods are molecular (PCR of different types), which are characterized by their sensitivity and speed.