Lymphocystis virus disease

Lymphocystis disease (LCD) is a chronic self-limiting disease involving a number of teleost species throughout the world. It is caused by the lymphocystis disease virus (LCDV) and characterized by white nodules affecting the fish's skin/fins. Although LCD is frequently benign, it may be responsible for economic losses related to poor growth, nonmarketability of diseased fish, and secondary bacterial infections. Currently, no specific prevention or therapeutic methods are available, and the control is based on the application of a biosecurity program including disinfection procedures, screening and quarantine of fish stocks that have to be introduced. Recent studies showed that LCDV causes systemic infection, and surviving fish can become asymptomatic carriers, thus presenting new challenges in the control of LCD. This chapter reviews the literature providing an overview of this insidious disease, including recent insights on pathogenesis and epidemiology, available methods for the diagnosis and future prospects to improve LCD control.