NAVLE Multisystemic

Aquatics Lymphocystis Study Guide

Lymphocystis disease (LCD) is a chronic viral disease of freshwater and marine teleost fish caused by Lymphocystis disease virus (LCDV), a member of the family Iridoviridae, genus Lymphocystivirus.

Overview and Clinical Importance

Lymphocystis disease (LCD) is a chronic viral disease of freshwater and marine teleost fish caused by Lymphocystis disease virus (LCDV), a member of the family Iridoviridae, genus Lymphocystivirus. The disease is characterized by distinctive wart-like or cauliflower-like nodules on the skin, fins, and occasionally gills. While generally self-limiting and non-fatal, LCD has significant economic implications in aquaculture due to reduced marketability.

LCD affects over 125 different fish species from 34 different families worldwide. Importantly, it does NOT affect cyprinids (goldfish, koi, barbs), catfish, or salmonids - a critical diagnostic consideration.

High-YieldLymphocystis is the MOST COMMON viral disease of aquarium fish. If you see wart-like nodules on a cichlid or clownfish, think lymphocystis. If on a goldfish or koi, think epitheliocystis instead!
Species Primary Host Genome Size
LCDV-1 European flounder 102-108 kbp
LCDV-2 Japanese flounder 186 kbp
LCDV-3 Gilthead seabream 208 kbp
LCDV-4 White croaker 211 kbp

Etiology and Viral Classification

Causative Agent

Lymphocystis disease is caused by Lymphocystis disease virus (LCDV), a large, icosahedral, double-stranded DNA virus:

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